Refactor error to use dynamic dispatch and traits

This is in preperation for dynamic import (#1789), which is more easily
implemented when errors are dynamic.

cli/compiler.rs

@@ -1,6 +1,4 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
-use crate::deno_error::err_check;
-use crate::deno_error::DenoError;
 use crate::diagnostics::Diagnostic;
 use crate::msg;
 use crate::resources;
@@ -9,6 +7,7 @@ use crate::state::*;
 use crate::tokio_util;
 use crate::worker::Worker;
 use deno::Buf;
+use deno::ErrBox;
 use deno::ModuleSpecifier;
 use futures::Future;
 use futures::Stream;
@@ -96,7 +95,7 @@ pub fn bundle_async(
   state: ThreadSafeState,
   module_name: String,
   out_file: String,
-) -> impl Future<Item = (), Error = DenoError> {
+) -> impl Future<Item = (), Error = ErrBox> {
   debug!(
     "Invoking the compiler to bundle. module_name: {}",
     module_name
@@ -116,9 +115,9 @@ pub fn bundle_async(
     // as was done previously.
     state.clone(),
   );
-  err_check(worker.execute("denoMain()"));
+  worker.execute("denoMain()").unwrap();
-  err_check(worker.execute("workerMain()"));
+  worker.execute("workerMain()").unwrap();
-  err_check(worker.execute("compilerMain()"));
+  worker.execute("compilerMain()").unwrap();
 
   let resource = worker.state.resource.clone();
   let compiler_rid = resource.rid;
@@ -144,7 +143,7 @@ pub fn bundle_async(
         let json_str = std::str::from_utf8(&msg).unwrap();
         debug!("Message: {}", json_str);
         if let Some(diagnostics) = Diagnostic::from_emit_result(json_str) {
-          return Err(DenoError::from(diagnostics));
+          return Err(ErrBox::from(diagnostics));
         }
       }
 
@@ -156,7 +155,7 @@ pub fn bundle_async(
 pub fn compile_async(
   state: ThreadSafeState,
   module_meta_data: &ModuleMetaData,
-) -> impl Future<Item = ModuleMetaData, Error = DenoError> {
+) -> impl Future<Item = ModuleMetaData, Error = ErrBox> {
   let module_name = module_meta_data.module_name.clone();
 
   debug!(
@@ -178,9 +177,9 @@ pub fn compile_async(
     // as was done previously.
     state.clone(),
   );
-  err_check(worker.execute("denoMain()"));
+  worker.execute("denoMain()").unwrap();
-  err_check(worker.execute("workerMain()"));
+  worker.execute("workerMain()").unwrap();
-  err_check(worker.execute("compilerMain()"));
+  worker.execute("compilerMain()").unwrap();
 
   let compiling_job = state.progress.add("Compile", &module_name);
 
@@ -211,7 +210,7 @@ pub fn compile_async(
         let json_str = std::str::from_utf8(&msg).unwrap();
         debug!("Message: {}", json_str);
         if let Some(diagnostics) = Diagnostic::from_emit_result(json_str) {
-          return Err(DenoError::from(diagnostics));
+          return Err(ErrBox::from(diagnostics));
         }
       }
 
@@ -242,7 +241,7 @@ pub fn compile_async(
 pub fn compile_sync(
   state: ThreadSafeState,
   module_meta_data: &ModuleMetaData,
-) -> Result<ModuleMetaData, DenoError> {
+) -> Result<ModuleMetaData, ErrBox> {
   tokio_util::block_on(compile_async(state, module_meta_data))
 }
 

cli/deno_dir.rs

@@ -1,9 +1,8 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
 use crate::compiler::ModuleMetaData;
-use crate::deno_error;
 use crate::deno_error::DenoError;
-use crate::deno_error::DenoResult;
 use crate::deno_error::ErrorKind;
+use crate::deno_error::GetErrorKind;
 use crate::fs as deno_fs;
 use crate::http_util;
 use crate::msg;
@@ -11,6 +10,7 @@ use crate::progress::Progress;
 use crate::source_maps::SourceMapGetter;
 use crate::tokio_util;
 use crate::version;
+use deno::ErrBox;
 use deno::ModuleSpecifier;
 use dirs;
 use futures::future::{loop_fn, Either, Loop};
@@ -20,8 +20,6 @@ use ring;
 use serde_json;
 use std;
 use std::collections::HashSet;
-use std::fmt;
-use std::fmt::Display;
 use std::fmt::Write;
 use std::fs;
 use std::path::Path;
@@ -34,36 +32,6 @@ use std::sync::Mutex;
 use url;
 use url::Url;
 
-// TODO: DenoDirError is temporary solution, should be upgraded during rewrite
-#[derive(Debug, PartialEq)]
-pub enum DenoDirErrorKind {
-  UnsupportedFetchScheme,
-}
-
-#[derive(Debug)]
-pub struct DenoDirError {
-  pub message: String,
-  pub kind: DenoDirErrorKind,
-}
-
-impl DenoDirError {
-  pub fn new(message: String, kind: DenoDirErrorKind) -> Self {
-    DenoDirError { message, kind }
-  }
-}
-
-impl std::error::Error for DenoDirError {
-  fn description(&self) -> &str {
-    &*self.message
-  }
-}
-
-impl Display for DenoDirError {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-    writeln!(f, "{}", self.message)
-  }
-}
-
 const SUPPORTED_URL_SCHEMES: [&str; 3] = ["http", "https", "file"];
 
 fn normalize_path(path: &Path) -> PathBuf {
@@ -198,13 +166,13 @@ impl DenoDir {
     specifier: &ModuleSpecifier,
     use_cache: bool,
     no_fetch: bool,
-  ) -> impl Future<Item = ModuleMetaData, Error = deno_error::DenoError> {
+  ) -> impl Future<Item = ModuleMetaData, Error = ErrBox> {
     let module_url = specifier.as_url().to_owned();
     debug!("fetch_module_meta_data. specifier {} ", &module_url);
 
     let result = self.url_to_deps_path(&module_url);
     if let Err(err) = result {
-      return Either::A(futures::future::err(DenoError::from(err)));
+      return Either::A(futures::future::err(err));
     }
     let deps_filepath = result.unwrap();
 
@@ -223,20 +191,17 @@ impl DenoDir {
         use_cache,
         no_fetch,
       ).then(move |result| {
-        let mut out = match result {
+        let mut out = result.map_err(|err| {
-          Ok(out) => out,
-          Err(err) => {
           if err.kind() == ErrorKind::NotFound {
             // For NotFound, change the message to something better.
-              return Err(deno_error::new(
+            DenoError::new(
               ErrorKind::NotFound,
               format!("Cannot resolve module \"{}\"", module_url.to_string()),
-              ));
+            ).into()
           } else {
-              return Err(err);
+            err
           }
-          }
+        })?;
-        };
 
         if out.source_code.starts_with(b"#!") {
           out.source_code = filter_shebang(out.source_code);
@@ -290,7 +255,7 @@ impl DenoDir {
     specifier: &ModuleSpecifier,
     use_cache: bool,
     no_fetch: bool,
-  ) -> Result<ModuleMetaData, deno_error::DenoError> {
+  ) -> Result<ModuleMetaData, ErrBox> {
     tokio_util::block_on(
       self.fetch_module_meta_data_async(specifier, use_cache, no_fetch),
     )
@@ -303,20 +268,17 @@ impl DenoDir {
   ///
   /// For specifier starting with `http://` and `https://` it returns
   /// path to DenoDir dependency directory.
-  pub fn url_to_deps_path(
+  pub fn url_to_deps_path(self: &Self, url: &Url) -> Result<PathBuf, ErrBox> {
-    self: &Self,
-    url: &Url,
-  ) -> Result<PathBuf, DenoDirError> {
     let filename = match url.scheme() {
       "file" => url.to_file_path().unwrap(),
       "https" => get_cache_filename(self.deps_https.as_path(), &url),
       "http" => get_cache_filename(self.deps_http.as_path(), &url),
       scheme => {
         return Err(
-          DenoDirError::new(
+          DenoError::new(
+            ErrorKind::UnsupportedFetchScheme,
             format!("Unsupported scheme \"{}\" for module \"{}\". Supported schemes: {:#?}", scheme, url, SUPPORTED_URL_SCHEMES),
-            DenoDirErrorKind::UnsupportedFetchScheme
+          ).into()
-          )
         );
       }
     };
@@ -389,7 +351,7 @@ fn get_source_code_async(
   filepath: PathBuf,
   use_cache: bool,
   no_fetch: bool,
-) -> impl Future<Item = ModuleMetaData, Error = DenoError> {
+) -> impl Future<Item = ModuleMetaData, Error = ErrBox> {
   let filename = filepath.to_str().unwrap().to_string();
   let module_name = module_url.to_string();
   let url_scheme = module_url.scheme();
@@ -425,23 +387,23 @@ fn get_source_code_async(
   // If not remote file stop here!
   if !is_module_remote {
     debug!("not remote file stop here");
-    return Either::A(futures::future::err(DenoError::from(
+    return Either::A(futures::future::err(
       std::io::Error::new(
         std::io::ErrorKind::NotFound,
         format!("cannot find local file '{}'", filename),
-      ),
+      ).into(),
-    )));
+    ));
   }
 
   // If remote downloads are not allowed stop here!
   if no_fetch {
     debug!("remote file with no_fetch stop here");
-    return Either::A(futures::future::err(DenoError::from(
+    return Either::A(futures::future::err(
       std::io::Error::new(
         std::io::ErrorKind::NotFound,
         format!("cannot find remote file '{}' in cache", filename),
-      ),
+      ).into(),
-    )));
+    ));
   }
 
   debug!("is remote but didn't find module");
@@ -456,10 +418,12 @@ fn get_source_code_async(
           download_cache.mark(&module_name);
           Ok(output)
         }
-        None => Err(DenoError::from(std::io::Error::new(
+        None => Err(
+          std::io::Error::new(
             std::io::ErrorKind::NotFound,
             format!("cannot find remote file '{}'", filename),
-        ))),
+          ).into(),
+        ),
       },
     ),
   )
@@ -474,7 +438,7 @@ fn get_source_code(
   filepath: PathBuf,
   use_cache: bool,
   no_fetch: bool,
-) -> DenoResult<ModuleMetaData> {
+) -> Result<ModuleMetaData, ErrBox> {
   tokio_util::block_on(get_source_code_async(
     deno_dir, module_url, filepath, use_cache, no_fetch,
   ))
@@ -595,7 +559,7 @@ fn save_module_code_and_headers(
   source: &str,
   maybe_content_type: Option<String>,
   maybe_initial_filepath: Option<PathBuf>,
-) -> DenoResult<()> {
+) -> Result<(), ErrBox> {
   match filepath.parent() {
     Some(ref parent) => fs::create_dir_all(parent),
     None => Ok(()),
@@ -636,7 +600,7 @@ fn fetch_remote_source_async(
   deno_dir: &DenoDir,
   module_url: &Url,
   filepath: &Path,
-) -> impl Future<Item = Option<ModuleMetaData>, Error = DenoError> {
+) -> impl Future<Item = Option<ModuleMetaData>, Error = ErrBox> {
   use crate::http_util::FetchOnceResult;
 
   let download_job = deno_dir.progress.add("Download", &module_url.to_string());
@@ -664,11 +628,13 @@ fn fetch_remote_source_async(
     )| {
       let module_uri = url_into_uri(&module_url);
       // Single pass fetch, either yields code or yields redirect.
-      http_util::fetch_string_once(module_uri).and_then(move |fetch_once_result| {
+      http_util::fetch_string_once(module_uri).and_then(
+        move |fetch_once_result| {
           match fetch_once_result {
             FetchOnceResult::Redirect(uri) => {
               // If redirects, update module_name and filename for next looped call.
-            let new_module_url = Url::parse(&uri.to_string()).expect("http::uri::Uri should be parseable as Url");
+              let new_module_url = Url::parse(&uri.to_string())
+                .expect("http::uri::Uri should be parseable as Url");
               let new_filepath = dir.url_to_deps_path(&new_module_url)?;
 
               if maybe_initial_module_name.is_none() {
@@ -716,9 +682,11 @@ fn fetch_remote_source_async(
               Ok(Loop::Break(Some(module_meta_data)))
             }
           }
-      })
         },
-  ).then(move |r| {
+      )
+    },
+  )
+  .then(move |r| {
     // Explicit drop to keep reference alive until future completes.
     drop(download_job);
     r
@@ -731,7 +699,7 @@ fn fetch_remote_source(
   deno_dir: &DenoDir,
   module_url: &Url,
   filepath: &Path,
-) -> DenoResult<Option<ModuleMetaData>> {
+) -> Result<Option<ModuleMetaData>, ErrBox> {
   tokio_util::block_on(fetch_remote_source_async(
     deno_dir, module_url, filepath,
   ))
@@ -751,7 +719,7 @@ fn fetch_local_source(
   module_url: &Url,
   filepath: &Path,
   module_initial_source_name: Option<String>,
-) -> DenoResult<Option<ModuleMetaData>> {
+) -> Result<Option<ModuleMetaData>, ErrBox> {
   let source_code_headers = get_source_code_headers(&filepath);
   // If source code headers says that it would redirect elsewhere,
   // (meaning that the source file might not exist; only .headers.json is present)
@@ -907,7 +875,7 @@ fn save_source_code_headers(
 
 // TODO(bartlomieju): this method should be moved, it doesn't belong to deno_dir.rs
 //  it's a general utility
-pub fn resolve_from_cwd(path: &str) -> Result<(PathBuf, String), DenoError> {
+pub fn resolve_from_cwd(path: &str) -> Result<(PathBuf, String), ErrBox> {
   let candidate_path = Path::new(path);
 
   let resolved_path = if candidate_path.is_absolute() {
@@ -1669,8 +1637,8 @@ mod tests {
     for &test in test_cases.iter() {
       let url = Url::parse(test).unwrap();
       assert_eq!(
-        deno_dir.url_to_deps_path(&url).unwrap_err().kind,
+        deno_dir.url_to_deps_path(&url).unwrap_err().kind(),
-        DenoDirErrorKind::UnsupportedFetchScheme
+        ErrorKind::UnsupportedFetchScheme
       );
     }
   }

cli/deno_error.rs

@@ -1,76 +1,128 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
-use crate::deno_dir;
+use crate::diagnostics::Diagnostic;
-use crate::diagnostics;
+use crate::fmt_errors::JSError;
-use crate::fmt_errors::JSErrorColor;
+use crate::import_map::ImportMapError;
-use crate::import_map;
 pub use crate::msg::ErrorKind;
-use crate::resolve_addr::ResolveAddrError;
+use deno::AnyError;
-use crate::source_maps::apply_source_map;
+use deno::ErrBox;
-use crate::source_maps::SourceMapGetter;
-use deno::JSError;
 use deno::ModuleResolutionError;
+use http::uri;
 use hyper;
-#[cfg(unix)]
-use nix::{errno::Errno, Error as UnixError};
 use std;
+use std::error::Error;
 use std::fmt;
 use std::io;
-use std::str;
 use url;
 
-pub type DenoResult<T> = std::result::Result<T, DenoError>;
-
 #[derive(Debug)]
 pub struct DenoError {
-  repr: Repr,
+  kind: ErrorKind,
-}
+  msg: String,
-
-#[derive(Debug)]
-enum Repr {
-  Simple(ErrorKind, String),
-  IoErr(io::Error),
-  UrlErr(url::ParseError),
-  HyperErr(hyper::Error),
-  ImportMapErr(import_map::ImportMapError),
-  ModuleResolutionErr(ModuleResolutionError),
-  Diagnostic(diagnostics::Diagnostic),
-  JSError(JSError),
-  DenoDirErr(deno_dir::DenoDirError),
-}
-
-/// Create a new simple DenoError.
-pub fn new(kind: ErrorKind, msg: String) -> DenoError {
-  DenoError {
-    repr: Repr::Simple(kind, msg),
-  }
 }
 
 impl DenoError {
-  fn url_error_kind(err: url::ParseError) -> ErrorKind {
+  pub fn new(kind: ErrorKind, msg: String) -> Self {
-    use url::ParseError::*;
+    Self { kind, msg }
-    match err {
-      EmptyHost => ErrorKind::EmptyHost,
-      IdnaError => ErrorKind::IdnaError,
-      InvalidPort => ErrorKind::InvalidPort,
-      InvalidIpv4Address => ErrorKind::InvalidIpv4Address,
-      InvalidIpv6Address => ErrorKind::InvalidIpv6Address,
-      InvalidDomainCharacter => ErrorKind::InvalidDomainCharacter,
-      RelativeUrlWithoutBase => ErrorKind::RelativeUrlWithoutBase,
-      RelativeUrlWithCannotBeABaseBase => {
-        ErrorKind::RelativeUrlWithCannotBeABaseBase
-      }
-      SetHostOnCannotBeABaseUrl => ErrorKind::SetHostOnCannotBeABaseUrl,
-      Overflow => ErrorKind::Overflow,
   }
 }
 
-  pub fn kind(&self) -> ErrorKind {
+impl Error for DenoError {}
-    match self.repr {
+
-      Repr::Simple(kind, ref _msg) => kind,
+impl fmt::Display for DenoError {
-      // Repr::Simple(kind) => kind,
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-      Repr::IoErr(ref err) => {
+    f.pad(self.msg.as_str())
-        use std::io::ErrorKind::*;
+  }
-        match err.kind() {
+}
+
+#[derive(Debug)]
+struct StaticError(ErrorKind, &'static str);
+
+impl Error for StaticError {}
+
+impl fmt::Display for StaticError {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+    f.pad(self.1)
+  }
+}
+
+pub fn bad_resource() -> ErrBox {
+  StaticError(ErrorKind::BadResource, "bad resource id").into()
+}
+
+pub fn permission_denied() -> ErrBox {
+  StaticError(ErrorKind::PermissionDenied, "permission denied").into()
+}
+
+pub fn op_not_implemented() -> ErrBox {
+  StaticError(ErrorKind::OpNotAvailable, "op not implemented").into()
+}
+
+pub fn no_buffer_specified() -> ErrBox {
+  StaticError(ErrorKind::InvalidInput, "no buffer specified").into()
+}
+
+pub fn no_async_support() -> ErrBox {
+  StaticError(ErrorKind::NoAsyncSupport, "op doesn't support async calls")
+    .into()
+}
+
+pub fn no_sync_support() -> ErrBox {
+  StaticError(ErrorKind::NoSyncSupport, "op doesn't support sync calls").into()
+}
+
+pub fn invalid_address_syntax() -> ErrBox {
+  StaticError(ErrorKind::InvalidInput, "invalid address syntax").into()
+}
+
+pub trait GetErrorKind {
+  fn kind(&self) -> ErrorKind;
+}
+
+impl GetErrorKind for DenoError {
+  fn kind(&self) -> ErrorKind {
+    self.kind
+  }
+}
+
+impl GetErrorKind for StaticError {
+  fn kind(&self) -> ErrorKind {
+    self.0
+  }
+}
+
+impl GetErrorKind for JSError {
+  fn kind(&self) -> ErrorKind {
+    ErrorKind::JSError
+  }
+}
+
+impl GetErrorKind for Diagnostic {
+  fn kind(&self) -> ErrorKind {
+    ErrorKind::Diagnostic
+  }
+}
+
+impl GetErrorKind for ImportMapError {
+  fn kind(&self) -> ErrorKind {
+    ErrorKind::ImportMapError
+  }
+}
+
+impl GetErrorKind for ModuleResolutionError {
+  fn kind(&self) -> ErrorKind {
+    use ModuleResolutionError::*;
+    match self {
+      InvalidUrl(ref err) | InvalidBaseUrl(ref err) => err.kind(),
+      InvalidPath => ErrorKind::InvalidPath,
+      ImportPrefixMissing => ErrorKind::ImportPrefixMissing,
+    }
+  }
+}
+
+impl GetErrorKind for io::Error {
+  fn kind(&self) -> ErrorKind {
+    use io::ErrorKind::*;
+    match self.kind() {
       NotFound => ErrorKind::NotFound,
       PermissionDenied => ErrorKind::PermissionDenied,
       ConnectionRefused => ErrorKind::ConnectionRefused,
@@ -87,260 +139,101 @@ impl DenoError {
       TimedOut => ErrorKind::TimedOut,
       Interrupted => ErrorKind::Interrupted,
       WriteZero => ErrorKind::WriteZero,
-          Other => ErrorKind::Other,
       UnexpectedEof => ErrorKind::UnexpectedEof,
-          _ => unreachable!(),
+      _ => ErrorKind::Other,
-        }
-      }
-      Repr::UrlErr(err) => Self::url_error_kind(err),
-      Repr::HyperErr(ref err) => {
-        // For some reason hyper::errors::Kind is private.
-        if err.is_parse() {
-          ErrorKind::HttpParse
-        } else if err.is_user() {
-          ErrorKind::HttpUser
-        } else if err.is_canceled() {
-          ErrorKind::HttpCanceled
-        } else if err.is_closed() {
-          ErrorKind::HttpClosed
-        } else {
-          ErrorKind::HttpOther
-        }
-      }
-      Repr::ImportMapErr(ref _err) => ErrorKind::ImportMapError,
-      Repr::ModuleResolutionErr(err) => {
-        use ModuleResolutionError::*;
-        match err {
-          InvalidUrl(err) | InvalidBaseUrl(err) => Self::url_error_kind(err),
-          InvalidPath => ErrorKind::InvalidPath,
-          ImportPrefixMissing => ErrorKind::ImportPrefixMissing,
-        }
-      }
-      Repr::Diagnostic(ref _err) => ErrorKind::Diagnostic,
-      Repr::JSError(ref _err) => ErrorKind::JSError,
-      Repr::DenoDirErr(ref _err) => ErrorKind::DenoDirError,
-    }
-  }
-
-  pub fn apply_source_map<G: SourceMapGetter>(self, getter: &G) -> Self {
-    if let Repr::JSError(js_error) = self.repr {
-      return DenoError {
-        repr: Repr::JSError(apply_source_map(&js_error, getter)),
-      };
-    } else {
-      panic!("attempt to apply source map an unremappable error")
     }
   }
 }
 
-impl fmt::Display for DenoError {
+impl GetErrorKind for uri::InvalidUri {
-  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+  fn kind(&self) -> ErrorKind {
-    match self.repr {
+    // The http::uri::ErrorKind exists and is similar to url::ParseError.
-      Repr::Simple(_kind, ref err_str) => f.pad(err_str),
+    // However it is also private, so we can't get any details out.
-      Repr::IoErr(ref err) => err.fmt(f),
+    ErrorKind::InvalidUri
-      Repr::UrlErr(ref err) => err.fmt(f),
+  }
-      Repr::HyperErr(ref err) => err.fmt(f),
+}
-      Repr::ImportMapErr(ref err) => f.pad(&err.msg),
+
-      Repr::ModuleResolutionErr(ref err) => err.fmt(f),
+impl GetErrorKind for url::ParseError {
-      Repr::Diagnostic(ref err) => err.fmt(f),
+  fn kind(&self) -> ErrorKind {
-      Repr::JSError(ref err) => JSErrorColor(err).fmt(f),
+    use url::ParseError::*;
-      Repr::DenoDirErr(ref err) => err.fmt(f),
+    match self {
+      EmptyHost => ErrorKind::EmptyHost,
+      IdnaError => ErrorKind::IdnaError,
+      InvalidDomainCharacter => ErrorKind::InvalidDomainCharacter,
+      InvalidIpv4Address => ErrorKind::InvalidIpv4Address,
+      InvalidIpv6Address => ErrorKind::InvalidIpv6Address,
+      InvalidPort => ErrorKind::InvalidPort,
+      Overflow => ErrorKind::Overflow,
+      RelativeUrlWithCannotBeABaseBase => {
+        ErrorKind::RelativeUrlWithCannotBeABaseBase
+      }
+      RelativeUrlWithoutBase => ErrorKind::RelativeUrlWithoutBase,
+      SetHostOnCannotBeABaseUrl => ErrorKind::SetHostOnCannotBeABaseUrl,
     }
   }
 }
 
-impl std::error::Error for DenoError {
+impl GetErrorKind for hyper::Error {
-  fn description(&self) -> &str {
+  fn kind(&self) -> ErrorKind {
-    match self.repr {
+    match self {
-      Repr::Simple(_kind, ref msg) => msg.as_str(),
+      e if e.is_canceled() => ErrorKind::HttpCanceled,
-      Repr::IoErr(ref err) => err.description(),
+      e if e.is_closed() => ErrorKind::HttpClosed,
-      Repr::UrlErr(ref err) => err.description(),
+      e if e.is_parse() => ErrorKind::HttpParse,
-      Repr::HyperErr(ref err) => err.description(),
+      e if e.is_user() => ErrorKind::HttpUser,
-      Repr::ImportMapErr(ref err) => &err.msg,
+      _ => ErrorKind::HttpOther,
-      Repr::ModuleResolutionErr(ref err) => err.description(),
-      Repr::Diagnostic(ref err) => &err.items[0].message,
-      Repr::JSError(ref err) => &err.description(),
-      Repr::DenoDirErr(ref err) => err.description(),
-    }
-  }
-
-  fn cause(&self) -> Option<&dyn std::error::Error> {
-    match self.repr {
-      Repr::Simple(_kind, ref _msg) => None,
-      Repr::IoErr(ref err) => Some(err),
-      Repr::UrlErr(ref err) => Some(err),
-      Repr::HyperErr(ref err) => Some(err),
-      Repr::ImportMapErr(ref _err) => None,
-      Repr::ModuleResolutionErr(ref err) => err.source(),
-      Repr::Diagnostic(ref _err) => None,
-      Repr::JSError(ref err) => Some(err),
-      Repr::DenoDirErr(ref err) => Some(err),
-    }
-  }
-}
-
-impl From<io::Error> for DenoError {
-  #[inline]
-  fn from(err: io::Error) -> Self {
-    Self {
-      repr: Repr::IoErr(err),
-    }
-  }
-}
-
-impl From<url::ParseError> for DenoError {
-  #[inline]
-  fn from(err: url::ParseError) -> Self {
-    Self {
-      repr: Repr::UrlErr(err),
-    }
-  }
-}
-
-impl From<hyper::Error> for DenoError {
-  #[inline]
-  fn from(err: hyper::Error) -> Self {
-    Self {
-      repr: Repr::HyperErr(err),
-    }
-  }
-}
-
-impl From<ResolveAddrError> for DenoError {
-  fn from(e: ResolveAddrError) -> Self {
-    match e {
-      ResolveAddrError::Syntax => Self {
-        repr: Repr::Simple(
-          ErrorKind::InvalidInput,
-          "invalid address syntax".to_string(),
-        ),
-      },
-      ResolveAddrError::Resolution(io_err) => Self {
-        repr: Repr::IoErr(io_err),
-      },
     }
   }
 }
 
 #[cfg(unix)]
-impl From<UnixError> for DenoError {
+mod unix {
-  fn from(e: UnixError) -> Self {
+  use super::{ErrorKind, GetErrorKind};
-    match e {
+  use nix::errno::Errno::*;
-      UnixError::Sys(Errno::EPERM) => Self {
+  pub use nix::Error;
-        repr: Repr::Simple(
+  use nix::Error::Sys;
-          ErrorKind::PermissionDenied,
+
-          Errno::EPERM.desc().to_owned(),
+  impl GetErrorKind for Error {
-        ),
+    fn kind(&self) -> ErrorKind {
-      },
+      match self {
-      UnixError::Sys(Errno::EINVAL) => Self {
+        Sys(EPERM) => ErrorKind::PermissionDenied,
-        repr: Repr::Simple(
+        Sys(EINVAL) => ErrorKind::InvalidInput,
-          ErrorKind::InvalidInput,
+        Sys(ENOENT) => ErrorKind::NotFound,
-          Errno::EINVAL.desc().to_owned(),
+        Sys(_) => ErrorKind::UnixError,
-        ),
+        _ => ErrorKind::Other,
-      },
+      }
-      UnixError::Sys(Errno::ENOENT) => Self {
-        repr: Repr::Simple(
-          ErrorKind::NotFound,
-          Errno::ENOENT.desc().to_owned(),
-        ),
-      },
-      UnixError::Sys(err) => Self {
-        repr: Repr::Simple(ErrorKind::UnixError, err.desc().to_owned()),
-      },
-      _ => Self {
-        repr: Repr::Simple(ErrorKind::Other, format!("{}", e)),
-      },
     }
   }
 }
 
-impl From<import_map::ImportMapError> for DenoError {
+impl GetErrorKind for dyn AnyError {
-  fn from(err: import_map::ImportMapError) -> Self {
+  fn kind(&self) -> ErrorKind {
-    Self {
+    use self::GetErrorKind as Get;
-      repr: Repr::ImportMapErr(err),
+
-    }
+    #[cfg(unix)]
-  }
+    fn unix_error_kind(err: &dyn AnyError) -> Option<ErrorKind> {
+      err.downcast_ref::<unix::Error>().map(Get::kind)
     }
 
-impl From<deno_dir::DenoDirError> for DenoError {
+    #[cfg(not(unix))]
-  fn from(err: deno_dir::DenoDirError) -> Self {
+    fn unix_error_kind(_: &dyn AnyError) -> Option<ErrorKind> {
-    Self {
+      None
-      repr: Repr::DenoDirErr(err),
-    }
-  }
     }
 
-impl From<ModuleResolutionError> for DenoError {
+    None
-  fn from(err: ModuleResolutionError) -> Self {
+      .or_else(|| self.downcast_ref::<DenoError>().map(Get::kind))
-    Self {
+      .or_else(|| self.downcast_ref::<Diagnostic>().map(Get::kind))
-      repr: Repr::ModuleResolutionErr(err),
+      .or_else(|| self.downcast_ref::<hyper::Error>().map(Get::kind))
-    }
+      .or_else(|| self.downcast_ref::<ImportMapError>().map(Get::kind))
-  }
+      .or_else(|| self.downcast_ref::<io::Error>().map(Get::kind))
-}
+      .or_else(|| self.downcast_ref::<JSError>().map(Get::kind))
-
+      .or_else(|| self.downcast_ref::<ModuleResolutionError>().map(Get::kind))
-impl From<diagnostics::Diagnostic> for DenoError {
+      .or_else(|| self.downcast_ref::<StaticError>().map(Get::kind))
-  fn from(diagnostic: diagnostics::Diagnostic) -> Self {
+      .or_else(|| self.downcast_ref::<uri::InvalidUri>().map(Get::kind))
-    Self {
+      .or_else(|| self.downcast_ref::<url::ParseError>().map(Get::kind))
-      repr: Repr::Diagnostic(diagnostic),
+      .or_else(|| unix_error_kind(self))
-    }
+      .unwrap_or_else(|| {
-  }
+        panic!("Can't get ErrorKind for {:?}", self);
-}
+      })
-
-impl From<JSError> for DenoError {
-  fn from(err: JSError) -> Self {
-    Self {
-      repr: Repr::JSError(err),
-    }
-  }
-}
-
-pub fn bad_resource() -> DenoError {
-  new(ErrorKind::BadResource, String::from("bad resource id"))
-}
-
-pub fn permission_denied() -> DenoError {
-  new(
-    ErrorKind::PermissionDenied,
-    String::from("permission denied"),
-  )
-}
-
-pub fn op_not_implemented() -> DenoError {
-  new(
-    ErrorKind::OpNotAvailable,
-    String::from("op not implemented"),
-  )
-}
-
-pub fn worker_init_failed() -> DenoError {
-  // TODO(afinch7) pass worker error data through here
-  new(
-    ErrorKind::WorkerInitFailed,
-    String::from("worker init failed"),
-  )
-}
-
-pub fn no_buffer_specified() -> DenoError {
-  new(ErrorKind::InvalidInput, String::from("no buffer specified"))
-}
-
-pub fn no_async_support() -> DenoError {
-  new(
-    ErrorKind::NoAsyncSupport,
-    String::from("op doesn't support async calls"),
-  )
-}
-
-pub fn no_sync_support() -> DenoError {
-  new(
-    ErrorKind::NoSyncSupport,
-    String::from("op doesn't support sync calls"),
-  )
-}
-
-pub fn err_check<R>(r: Result<R, DenoError>) {
-  if let Err(e) = r {
-    panic!(e.to_string());
   }
 }
 
@@ -348,16 +241,15 @@ pub fn err_check<R>(r: Result<R, DenoError>) {
 mod tests {
   use super::*;
   use crate::ansi::strip_ansi_codes;
-  use crate::deno_dir::DenoDirError;
-  use crate::deno_dir::DenoDirErrorKind;
   use crate::diagnostics::Diagnostic;
   use crate::diagnostics::DiagnosticCategory;
   use crate::diagnostics::DiagnosticItem;
-  use crate::import_map::ImportMapError;
+  use deno::ErrBox;
   use deno::StackFrame;
+  use deno::V8Exception;
 
   fn js_error() -> JSError {
-    JSError {
+    JSError::new(V8Exception {
       message: "Error: foo bar".to_string(),
       source_line: None,
       script_resource_name: None,
@@ -396,7 +288,7 @@ mod tests {
           is_wasm: false,
         },
       ],
-    }
+    })
   }
 
   fn diagnostic() -> Diagnostic {
@@ -436,22 +328,6 @@ mod tests {
     }
   }
 
-  struct MockSourceMapGetter {}
-
-  impl SourceMapGetter for MockSourceMapGetter {
-    fn get_source_map(&self, _script_name: &str) -> Option<Vec<u8>> {
-      Some(vec![])
-    }
-
-    fn get_source_line(
-      &self,
-      _script_name: &str,
-      _line: usize,
-    ) -> Option<String> {
-      None
-    }
-  }
-
   fn io_error() -> io::Error {
     io::Error::from(io::ErrorKind::NotFound)
   }
@@ -466,30 +342,24 @@ mod tests {
     }
   }
 
-  fn deno_dir_error() -> DenoDirError {
-    DenoDirError::new(
-      "a deno dir error".to_string(),
-      DenoDirErrorKind::UnsupportedFetchScheme,
-    )
-  }
-
   #[test]
   fn test_simple_error() {
-    let err = new(ErrorKind::NoError, "foo".to_string());
+    let err =
+      ErrBox::from(DenoError::new(ErrorKind::NoError, "foo".to_string()));
     assert_eq!(err.kind(), ErrorKind::NoError);
     assert_eq!(err.to_string(), "foo");
   }
 
   #[test]
   fn test_io_error() {
-    let err = DenoError::from(io_error());
+    let err = ErrBox::from(io_error());
     assert_eq!(err.kind(), ErrorKind::NotFound);
     assert_eq!(err.to_string(), "entity not found");
   }
 
   #[test]
   fn test_url_error() {
-    let err = DenoError::from(url_error());
+    let err = ErrBox::from(url_error());
     assert_eq!(err.kind(), ErrorKind::EmptyHost);
     assert_eq!(err.to_string(), "empty host");
   }
@@ -498,32 +368,25 @@ mod tests {
 
   #[test]
   fn test_diagnostic() {
-    let err = DenoError::from(diagnostic());
+    let err = ErrBox::from(diagnostic());
     assert_eq!(err.kind(), ErrorKind::Diagnostic);
     assert_eq!(strip_ansi_codes(&err.to_string()), "error TS2322: Example 1\n\n► deno/tests/complex_diagnostics.ts:19:3\n\n19   values: o => [\n     ~~~~~~\n\nerror TS2000: Example 2\n\n► /foo/bar.ts:129:3\n\n129   values: undefined,\n      ~~~~~~\n\n\nFound 2 errors.\n");
   }
 
   #[test]
   fn test_js_error() {
-    let err = DenoError::from(js_error());
+    let err = ErrBox::from(js_error());
     assert_eq!(err.kind(), ErrorKind::JSError);
     assert_eq!(strip_ansi_codes(&err.to_string()), "error: Error: foo bar\n    at foo (foo_bar.ts:5:17)\n    at qat (bar_baz.ts:6:21)\n    at deno_main.js:2:2");
   }
 
   #[test]
   fn test_import_map_error() {
-    let err = DenoError::from(import_map_error());
+    let err = ErrBox::from(import_map_error());
     assert_eq!(err.kind(), ErrorKind::ImportMapError);
     assert_eq!(err.to_string(), "an import map error");
   }
 
-  #[test]
-  fn test_deno_dir_error() {
-    let err = DenoError::from(deno_dir_error());
-    assert_eq!(err.kind(), ErrorKind::DenoDirError);
-    assert_eq!(err.to_string(), "a deno dir error\n");
-  }
-
   #[test]
   fn test_bad_resource() {
     let err = bad_resource();
@@ -545,13 +408,6 @@ mod tests {
     assert_eq!(err.to_string(), "op not implemented");
   }
 
-  #[test]
-  fn test_worker_init_failed() {
-    let err = worker_init_failed();
-    assert_eq!(err.kind(), ErrorKind::WorkerInitFailed);
-    assert_eq!(err.to_string(), "worker init failed");
-  }
-
   #[test]
   fn test_no_buffer_specified() {
     let err = no_buffer_specified();
@@ -572,20 +428,4 @@ mod tests {
     assert_eq!(err.kind(), ErrorKind::NoSyncSupport);
     assert_eq!(err.to_string(), "op doesn't support sync calls");
   }
-
-  #[test]
-  #[should_panic]
-  fn test_apply_source_map_invalid() {
-    let getter = MockSourceMapGetter {};
-    let err = new(ErrorKind::NotFound, "not found".to_string());
-    err.apply_source_map(&getter);
-  }
-
-  #[test]
-  #[should_panic]
-  fn test_err_check() {
-    err_check(
-      Err(new(ErrorKind::NotFound, "foo".to_string())) as Result<(), DenoError>
-    );
-  }
 }

cli/diagnostics.rs

@@ -7,6 +7,7 @@ use crate::fmt_errors::format_maybe_source_name;
 use crate::fmt_errors::DisplayFormatter;
 use serde_json;
 use serde_json::value::Value;
+use std::error::Error;
 use std::fmt;
 
 #[derive(Debug, PartialEq, Clone)]
@@ -66,6 +67,12 @@ impl fmt::Display for Diagnostic {
   }
 }
 
+impl Error for Diagnostic {
+  fn description(&self) -> &str {
+    &self.items[0].message
+  }
+}
+
 #[derive(Debug, PartialEq, Clone)]
 pub struct DiagnosticItem {
   /// The top level message relating to the diagnostic item.

cli/dispatch_minimal.rs

@@ -127,10 +127,11 @@ mod ops {
   use crate::deno_error;
   use crate::resources;
   use crate::tokio_write;
+  use deno::ErrBox;
   use deno::PinnedBuf;
   use futures::Future;
 
-  type MinimalOp = dyn Future<Item = i32, Error = deno_error::DenoError> + Send;
+  type MinimalOp = dyn Future<Item = i32, Error = ErrBox> + Send;
 
   pub fn read(rid: i32, zero_copy: Option<PinnedBuf>) -> Box<MinimalOp> {
     debug!("read rid={}", rid);
@@ -144,7 +145,7 @@ mod ops {
       None => Box::new(futures::future::err(deno_error::bad_resource())),
       Some(resource) => Box::new(
         tokio::io::read(resource, zero_copy)
-          .map_err(deno_error::DenoError::from)
+          .map_err(ErrBox::from)
           .and_then(move |(_resource, _buf, nread)| Ok(nread as i32)),
       ),
     }
@@ -162,7 +163,7 @@ mod ops {
       None => Box::new(futures::future::err(deno_error::bad_resource())),
       Some(resource) => Box::new(
         tokio_write::write(resource, zero_copy)
-          .map_err(deno_error::DenoError::from)
+          .map_err(ErrBox::from)
           .and_then(move |(_resource, _buf, nwritten)| Ok(nwritten as i32)),
       ),
     }

cli/fmt_errors.rs

@@ -1,8 +1,12 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
 //! This mod provides DenoError to unify errors across Deno.
 use crate::ansi;
-use deno::JSError;
+use crate::source_maps::apply_source_map;
+use crate::source_maps::SourceMapGetter;
+use deno::ErrBox;
 use deno::StackFrame;
+use deno::V8Exception;
+use std::error::Error;
 use std::fmt;
 
 /// A trait which specifies parts of a diagnostic like item needs to be able to
@@ -104,10 +108,50 @@ pub fn format_error_message(msg: String) -> String {
   format!("{} {}", preamble, msg)
 }
 
-/// Wrapper around JSError which provides color to_string.
+fn format_stack_frame(frame: &StackFrame) -> String {
-pub struct JSErrorColor<'a>(pub &'a JSError);
+  // Note when we print to string, we change from 0-indexed to 1-indexed.
+  let function_name = ansi::italic_bold(frame.function_name.clone());
+  let source_loc =
+    format_source_name(frame.script_name.clone(), frame.line, frame.column);
 
-impl<'a> DisplayFormatter for JSErrorColor<'a> {
+  if !frame.function_name.is_empty() {
+    format!("    at {} ({})", function_name, source_loc)
+  } else if frame.is_eval {
+    format!("    at eval ({})", source_loc)
+  } else {
+    format!("    at {}", source_loc)
+  }
+}
+
+/// Wrapper around V8Exception which provides color to_string.
+#[derive(Debug)]
+pub struct JSError(V8Exception);
+
+impl JSError {
+  pub fn new(v8_exception: V8Exception) -> Self {
+    Self(v8_exception)
+  }
+
+  pub fn from_json(
+    json_str: &str,
+    source_map_getter: &impl SourceMapGetter,
+  ) -> ErrBox {
+    let unmapped_exception = V8Exception::from_json(json_str).unwrap();
+    Self::from_v8_exception(unmapped_exception, source_map_getter)
+  }
+
+  pub fn from_v8_exception(
+    unmapped_exception: V8Exception,
+    source_map_getter: &impl SourceMapGetter,
+  ) -> ErrBox {
+    let mapped_exception =
+      apply_source_map(&unmapped_exception, source_map_getter);
+    let js_error = Self(mapped_exception);
+    ErrBox::from(js_error)
+  }
+}
+
+impl DisplayFormatter for JSError {
   fn format_category_and_code(&self) -> String {
     "".to_string()
   }
@@ -136,7 +180,7 @@ impl<'a> DisplayFormatter for JSErrorColor<'a> {
   }
 
   fn format_source_name(&self) -> String {
-    let e = self.0;
+    let e = &self.0;
     if e.script_resource_name.is_none() {
       return "".to_string();
     }
@@ -152,7 +196,7 @@ impl<'a> DisplayFormatter for JSErrorColor<'a> {
   }
 }
 
-impl<'a> fmt::Display for JSErrorColor<'a> {
+impl fmt::Display for JSError {
   fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
     write!(
       f,
@@ -163,39 +207,21 @@ impl<'a> fmt::Display for JSErrorColor<'a> {
     )?;
 
     for frame in &self.0.frames {
-      write!(f, "\n{}", StackFrameColor(&frame).to_string())?;
+      write!(f, "\n{}", format_stack_frame(&frame))?;
     }
     Ok(())
   }
 }
 
-struct StackFrameColor<'a>(&'a StackFrame);
+impl Error for JSError {}
-
-impl<'a> fmt::Display for StackFrameColor<'a> {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-    let frame = self.0;
-    // Note when we print to string, we change from 0-indexed to 1-indexed.
-    let function_name = ansi::italic_bold(frame.function_name.clone());
-    let script_line_column =
-      format_source_name(frame.script_name.clone(), frame.line, frame.column);
-
-    if !frame.function_name.is_empty() {
-      write!(f, "    at {} ({})", function_name, script_line_column)
-    } else if frame.is_eval {
-      write!(f, "    at eval ({})", script_line_column)
-    } else {
-      write!(f, "    at {}", script_line_column)
-    }
-  }
-}
 
 #[cfg(test)]
 mod tests {
   use super::*;
   use crate::ansi::strip_ansi_codes;
 
-  fn error1() -> JSError {
+  fn error1() -> V8Exception {
-    JSError {
+    V8Exception {
       message: "Error: foo bar".to_string(),
       source_line: None,
       script_resource_name: None,
@@ -240,7 +266,7 @@ mod tests {
   #[test]
   fn js_error_to_string() {
     let e = error1();
-    assert_eq!("error: Error: foo bar\n    at foo (foo_bar.ts:5:17)\n    at qat (bar_baz.ts:6:21)\n    at deno_main.js:2:2", strip_ansi_codes(&JSErrorColor(&e).to_string()));
+    assert_eq!("error: Error: foo bar\n    at foo (foo_bar.ts:5:17)\n    at qat (bar_baz.ts:6:21)\n    at deno_main.js:2:2", strip_ansi_codes(&JSError(e).to_string()));
   }
 
   #[test]

cli/fs.rs

@@ -5,6 +5,7 @@ use std::io::ErrorKind;
 use std::io::Write;
 use std::path::{Path, PathBuf};
 
+use deno::ErrBox;
 use rand;
 use rand::Rng;
 
@@ -15,8 +16,6 @@ use std::os::unix::fs::DirBuilderExt;
 #[cfg(any(unix))]
 use std::os::unix::fs::PermissionsExt;
 
-use crate::deno_error::DenoResult;
-
 pub fn write_file<T: AsRef<[u8]>>(
   filename: &Path,
   data: T,
@@ -114,18 +113,16 @@ pub fn normalize_path(path: &Path) -> String {
 }
 
 #[cfg(unix)]
-pub fn chown(path: &str, uid: u32, gid: u32) -> DenoResult<()> {
+pub fn chown(path: &str, uid: u32, gid: u32) -> Result<(), ErrBox> {
-  use crate::deno_error::DenoError;
   let nix_uid = Uid::from_raw(uid);
   let nix_gid = Gid::from_raw(gid);
   unix_chown(path, Option::Some(nix_uid), Option::Some(nix_gid))
-    .map_err(DenoError::from)
+    .map_err(ErrBox::from)
 }
 
 #[cfg(not(unix))]
-pub fn chown(_path: &str, _uid: u32, _gid: u32) -> DenoResult<()> {
+pub fn chown(_path: &str, _uid: u32, _gid: u32) -> Result<(), ErrBox> {
   // Noop
   // TODO: implement chown for Windows
-  use crate::deno_error;
+  Err(crate::deno_error::op_not_implemented())
-  Err(deno_error::op_not_implemented())
 }

cli/http_util.rs

@@ -1,6 +1,7 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
 use crate::deno_error;
 use crate::deno_error::DenoError;
+use deno::ErrBox;
 #[cfg(test)]
 use futures::future::{loop_fn, Loop};
 use futures::{future, Future, Stream};
@@ -57,13 +58,13 @@ fn resolve_uri_from_location(base_uri: &Uri, location: &str) -> Uri {
   }
 }
 
-#[cfg(test)]
-use crate::deno_error::DenoResult;
 #[cfg(test)]
 use crate::tokio_util;
 #[cfg(test)]
 /// Synchronously fetchs the given HTTP URL. Returns (content, media_type).
-pub fn fetch_sync_string(module_name: &str) -> DenoResult<(String, String)> {
+pub fn fetch_sync_string(
+  module_name: &str,
+) -> Result<(String, String), ErrBox> {
   tokio_util::block_on(fetch_string(module_name))
 }
 
@@ -80,15 +81,15 @@ pub enum FetchOnceResult {
 /// yields Redirect(url).
 pub fn fetch_string_once(
   url: http::uri::Uri,
-) -> impl Future<Item = FetchOnceResult, Error = DenoError> {
+) -> impl Future<Item = FetchOnceResult, Error = ErrBox> {
   type FetchAttempt = (Option<String>, Option<String>, Option<FetchOnceResult>);
   let client = get_client();
   client
     .get(url.clone())
-    .map_err(DenoError::from)
+    .map_err(ErrBox::from)
     .and_then(
       move |response| -> Box<
-        dyn Future<Item = FetchAttempt, Error = DenoError> + Send,
+        dyn Future<Item = FetchAttempt, Error = ErrBox> + Send,
       > {
         if response.status().is_redirection() {
           let location_string = response
@@ -108,10 +109,10 @@ pub fn fetch_string_once(
         } else if response.status().is_client_error()
           || response.status().is_server_error()
         {
-          return Box::new(future::err(deno_error::new(
+          return Box::new(future::err(DenoError::new(
             deno_error::ErrorKind::Other,
             format!("Import '{}' failed: {}", &url, response.status()),
-          )));
+          ).into()));
         }
         let content_type = response
           .headers()
@@ -121,7 +122,7 @@ pub fn fetch_string_once(
           .into_body()
           .concat2()
           .map(|body| String::from_utf8(body.to_vec()).ok())
-          .map_err(DenoError::from);
+          .map_err(ErrBox::from);
         Box::new(body.join3(future::ok(content_type), future::ok(None)))
       },
     )
@@ -142,7 +143,7 @@ pub fn fetch_string_once(
 /// Asynchronously fetchs the given HTTP URL. Returns (content, media_type).
 pub fn fetch_string(
   module_name: &str,
-) -> impl Future<Item = (String, String), Error = DenoError> {
+) -> impl Future<Item = (String, String), Error = ErrBox> {
   let url = module_name.parse::<Uri>().unwrap();
   let client = get_client();
   // TODO(kevinkassimo): consider set a max redirection counter
@@ -150,7 +151,7 @@ pub fn fetch_string(
   loop_fn((client, url), |(client, url)| {
     client
       .get(url.clone())
-      .map_err(DenoError::from)
+      .map_err(ErrBox::from)
       .and_then(move |response| {
         if response.status().is_redirection() {
           let location_string = response
@@ -165,10 +166,12 @@ pub fn fetch_string(
           return Ok(Loop::Continue((client, new_url)));
         }
         if !response.status().is_success() {
-          return Err(deno_error::new(
+          return Err(
+            DenoError::new(
               deno_error::ErrorKind::NotFound,
               "module not found".to_string(),
-          ));
+            ).into(),
+          );
         }
         Ok(Loop::Break(response))
       })
@@ -181,7 +184,7 @@ pub fn fetch_string(
       .into_body()
       .concat2()
       .map(|body| String::from_utf8(body.to_vec()).unwrap())
-      .map_err(DenoError::from);
+      .map_err(ErrBox::from);
     body.join(future::ok(content_type))
   }).and_then(|(body_string, maybe_content_type)| {
     future::ok((body_string, maybe_content_type.unwrap()))

cli/import_map.rs

@@ -3,6 +3,8 @@ use indexmap::IndexMap;
 use serde_json::Map;
 use serde_json::Value;
 use std::cmp::Ordering;
+use std::error::Error;
+use std::fmt;
 use std::fs;
 use url::Url;
 
@@ -19,6 +21,14 @@ impl ImportMapError {
   }
 }
 
+impl fmt::Display for ImportMapError {
+  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    f.pad(&self.msg)
+  }
+}
+
+impl Error for ImportMapError {}
+
 // NOTE: here is difference between deno and reference implementation - deno currently
 //  can't resolve URL with other schemes (eg. data:, about:, blob:)
 const SUPPORTED_FETCH_SCHEMES: [&str; 3] = ["http", "https", "file"];

cli/main.rs

@@ -46,11 +46,11 @@ pub mod version;
 pub mod worker;
 
 use crate::compiler::bundle_async;
-use crate::deno_error::DenoError;
 use crate::progress::Progress;
 use crate::state::ThreadSafeState;
 use crate::worker::Worker;
 use deno::v8_set_flags;
+use deno::ErrBox;
 use deno::ModuleSpecifier;
 use flags::DenoFlags;
 use flags::DenoSubcommand;
@@ -86,17 +86,14 @@ impl log::Log for Logger {
   fn flush(&self) {}
 }
 
-fn print_err_and_exit(err: DenoError) {
+fn print_err_and_exit(err: ErrBox) {
   eprintln!("{}", err.to_string());
   std::process::exit(1);
 }
 
-fn js_check<E>(r: Result<(), E>)
+fn js_check(r: Result<(), ErrBox>) {
-where
-  E: Into<DenoError>,
-{
   if let Err(err) = r {
-    print_err_and_exit(err.into());
+    print_err_and_exit(err);
   }
 }
 
@@ -264,7 +261,7 @@ fn xeval_command(flags: DenoFlags, argv: Vec<String>) {
       .then(|result| {
         js_check(result);
         Ok(())
-      }).map_err(|(err, _worker): (DenoError, Worker)| print_err_and_exit(err))
+      }).map_err(print_err_and_exit)
   });
   tokio_util::run(main_future);
 }
@@ -277,10 +274,10 @@ fn bundle_command(flags: DenoFlags, argv: Vec<String>) {
   let out_file = state.argv[2].clone();
   debug!(">>>>> bundle_async START");
   let bundle_future = bundle_async(state, main_module.to_string(), out_file)
-    .map_err(|e| {
+    .map_err(|err| {
       debug!("diagnostics returned, exiting!");
-      eprintln!("\n{}", e.to_string());
+      eprintln!("");
-      std::process::exit(1);
+      print_err_and_exit(err);
     }).and_then(move |_| {
       debug!(">>>>> bundle_async END");
       Ok(())
@@ -299,7 +296,7 @@ fn run_repl(flags: DenoFlags, argv: Vec<String>) {
       .then(|result| {
         js_check(result);
         Ok(())
-      }).map_err(|(err, _worker): (DenoError, Worker)| print_err_and_exit(err))
+      }).map_err(|(err, _worker): (ErrBox, Worker)| print_err_and_exit(err))
   });
   tokio_util::run(main_future);
 }

cli/msg.fbs

@@ -102,7 +102,6 @@ enum ErrorKind: byte {
   WouldBlock,
   InvalidInput,
   InvalidData,
-  InvalidPath,
   TimedOut,
   Interrupted,
   WriteZero,
@@ -142,8 +141,9 @@ enum ErrorKind: byte {
   NoAsyncSupport,
   NoSyncSupport,
   ImportMapError,
+  InvalidPath,
   ImportPrefixMissing,
-  DenoDirError,
+  UnsupportedFetchScheme,
 
   // other kinds
   Diagnostic,

cli/msg_util.rs

@@ -1,9 +1,7 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
 // Helpers for serialization.
-use crate::deno_error;
-use crate::deno_error::DenoResult;
 use crate::msg;
-
+use deno::ErrBox;
 use flatbuffers;
 use http::header::HeaderName;
 use http::uri::Uri;
@@ -97,14 +95,13 @@ pub fn serialize_http_response<'bldr>(
 pub fn deserialize_request(
   header_msg: msg::HttpHeader<'_>,
   body: Body,
-) -> DenoResult<Request<Body>> {
+) -> Result<Request<Body>, ErrBox> {
   let mut r = Request::new(body);
 
   assert!(header_msg.is_request());
 
   let u = header_msg.url().unwrap();
-  let u = Uri::from_str(u)
+  let u = Uri::from_str(u).map_err(ErrBox::from)?;
-    .map_err(|e| deno_error::new(msg::ErrorKind::InvalidUri, e.to_string()))?;
   *r.uri_mut() = u;
 
   if let Some(method) = header_msg.method() {

cli/ops.rs

@@ -3,12 +3,12 @@ use atty;
 use crate::ansi;
 use crate::deno_dir::resolve_from_cwd;
 use crate::deno_error;
-use crate::deno_error::err_check;
 use crate::deno_error::DenoError;
-use crate::deno_error::DenoResult;
 use crate::deno_error::ErrorKind;
+use crate::deno_error::GetErrorKind;
 use crate::dispatch_minimal::dispatch_minimal;
 use crate::dispatch_minimal::parse_min_record;
+use crate::fmt_errors::JSError;
 use crate::fs as deno_fs;
 use crate::http_util;
 use crate::msg;
@@ -28,7 +28,7 @@ use crate::version;
 use crate::worker::Worker;
 use deno::Buf;
 use deno::CoreOp;
-use deno::JSError;
+use deno::ErrBox;
 use deno::Loader;
 use deno::ModuleSpecifier;
 use deno::Op;
@@ -65,7 +65,7 @@ use std::os::unix::fs::PermissionsExt;
 #[cfg(unix)]
 use std::os::unix::process::ExitStatusExt;
 
-type CliOpResult = OpResult<DenoError>;
+type CliOpResult = OpResult<ErrBox>;
 
 type CliDispatchFn =
   fn(state: &ThreadSafeState, base: &msg::Base<'_>, data: Option<PinnedBuf>)
@@ -132,7 +132,7 @@ pub fn dispatch_all_legacy(
     }
     Ok(Op::Async(fut)) => {
       let result_fut = Box::new(
-        fut.or_else(move |err: DenoError| -> Result<Buf, ()> {
+        fut.or_else(move |err: ErrBox| -> Result<Buf, ()> {
           debug!("op err {}", err);
           // No matter whether we got an Err or Ok, we want a serialized message to
           // send back. So transform the DenoError into a Buf.
@@ -410,11 +410,9 @@ fn op_format_error(
 ) -> CliOpResult {
   assert!(data.is_none());
   let inner = base.inner_as_format_error().unwrap();
-  let orig_error = String::from(inner.error().unwrap());
+  let json_str = inner.error().unwrap();
-
+  let error = JSError::from_json(json_str, &state.dir);
-  let js_error = JSError::from_v8_exception(&orig_error).unwrap();
+  let error_string = error.to_string();
-  let error_mapped = DenoError::from(js_error).apply_source_map(&state.dir);
-  let error_string = error_mapped.to_string();
 
   let mut builder = FlatBufferBuilder::new();
   let new_error = builder.create_string(&error_string);
@@ -495,10 +493,10 @@ fn op_cache(
 
   if extension == ".map" {
     debug!("cache {:?}", source_map_path);
-    fs::write(source_map_path, contents).map_err(DenoError::from)?;
+    fs::write(source_map_path, contents).map_err(ErrBox::from)?;
   } else if extension == ".js" {
     debug!("cache {:?}", js_cache_path);
-    fs::write(js_cache_path, contents).map_err(DenoError::from)?;
+    fs::write(js_cache_path, contents).map_err(ErrBox::from)?;
   } else {
     unreachable!();
   }
@@ -735,16 +733,15 @@ fn op_fetch(
 
   let req = msg_util::deserialize_request(header, body)?;
 
-  let url_ = url::Url::parse(url).map_err(DenoError::from)?;
+  let url_ = url::Url::parse(url).map_err(ErrBox::from)?;
   state.check_net_url(url_)?;
 
   let client = http_util::get_client();
 
   debug!("Before fetch {}", url);
-  let future =
+  let future = client
-    client
     .request(req)
-      .map_err(DenoError::from)
+    .map_err(ErrBox::from)
     .and_then(move |res| {
       let builder = &mut FlatBufferBuilder::new();
       let header_off = msg_util::serialize_http_response(builder, &res);
@@ -778,9 +775,9 @@ fn op_fetch(
 
 // This is just type conversion. Implement From trait?
 // See https://github.com/tokio-rs/tokio/blob/ffd73a64e7ec497622b7f939e38017afe7124dc4/tokio-fs/src/lib.rs#L76-L85
-fn convert_blocking<F>(f: F) -> Poll<Buf, DenoError>
+fn convert_blocking<F>(f: F) -> Poll<Buf, ErrBox>
 where
-  F: FnOnce() -> DenoResult<Buf>,
+  F: FnOnce() -> Result<Buf, ErrBox>,
 {
   use futures::Async::*;
   match tokio_threadpool::blocking(f) {
@@ -793,7 +790,7 @@ where
 
 fn blocking<F>(is_sync: bool, f: F) -> CliOpResult
 where
-  F: 'static + Send + FnOnce() -> DenoResult<Buf>,
+  F: 'static + Send + FnOnce() -> Result<Buf, ErrBox>,
 {
   if is_sync {
     let result_buf = f()?;
@@ -981,10 +978,8 @@ fn op_open(
     }
   }
 
-  let op = open_options
+  let op = open_options.open(filename).map_err(ErrBox::from).and_then(
-    .open(filename)
+    move |fs_file| {
-    .map_err(DenoError::from)
-    .and_then(move |fs_file| {
       let resource = resources::add_fs_file(fs_file);
       let builder = &mut FlatBufferBuilder::new();
       let inner =
@@ -998,7 +993,8 @@ fn op_open(
           ..Default::default()
         },
       ))
-    });
+    },
+  );
   if base.sync() {
     let buf = op.wait()?;
     Ok(Op::Sync(buf))
@@ -1076,7 +1072,7 @@ fn op_read(
     None => Err(deno_error::bad_resource()),
     Some(resource) => {
       let op = tokio::io::read(resource, data.unwrap())
-        .map_err(DenoError::from)
+        .map_err(ErrBox::from)
         .and_then(move |(_resource, _buf, nread)| {
           let builder = &mut FlatBufferBuilder::new();
           let inner = msg::ReadRes::create(
@@ -1119,7 +1115,7 @@ fn op_write(
     None => Err(deno_error::bad_resource()),
     Some(resource) => {
       let op = tokio_write::write(resource, data.unwrap())
-        .map_err(DenoError::from)
+        .map_err(ErrBox::from)
         .and_then(move |(_resource, _buf, nwritten)| {
           let builder = &mut FlatBufferBuilder::new();
           let inner = msg::WriteRes::create(
@@ -1219,10 +1215,10 @@ fn op_copy_file(
     // See https://github.com/rust-lang/rust/issues/54800
     // Once the issue is reolved, we should remove this workaround.
     if cfg!(unix) && !from.is_file() {
-      return Err(deno_error::new(
+      return Err(
-        ErrorKind::NotFound,
+        DenoError::new(ErrorKind::NotFound, "File not found".to_string())
-        "File not found".to_string(),
+          .into(),
-      ));
+      );
     }
 
     fs::copy(&from, &to)?;
@@ -1431,10 +1427,9 @@ fn op_symlink(
   state.check_write(&newname_)?;
   // TODO Use type for Windows.
   if cfg!(windows) {
-    return Err(deno_error::new(
+    return Err(
-      ErrorKind::Other,
+      DenoError::new(ErrorKind::Other, "Not implemented".to_string()).into(),
-      "Not implemented".to_string(),
+    );
-    ));
   }
   blocking(base.sync(), move || {
     debug!("op_symlink {} {}", oldname.display(), newname.display());
@@ -1621,7 +1616,7 @@ fn op_listen(
   ok_buf(response_buf)
 }
 
-fn new_conn(cmd_id: u32, tcp_stream: TcpStream) -> DenoResult<Buf> {
+fn new_conn(cmd_id: u32, tcp_stream: TcpStream) -> Result<Buf, ErrBox> {
   let tcp_stream_resource = resources::add_tcp_stream(tcp_stream);
   // TODO forward socket_addr to client.
 
@@ -1658,7 +1653,7 @@ fn op_accept(
     None => Err(deno_error::bad_resource()),
     Some(server_resource) => {
       let op = tokio_util::accept(server_resource)
-        .map_err(DenoError::from)
+        .map_err(ErrBox::from)
         .and_then(move |(tcp_stream, _socket_addr)| {
           new_conn(cmd_id, tcp_stream)
         });
@@ -1686,12 +1681,9 @@ fn op_dial(
 
   state.check_net(&address)?;
 
-  let op =
+  let op = resolve_addr(address).and_then(move |addr| {
-    resolve_addr(address)
-      .map_err(DenoError::from)
-      .and_then(move |addr| {
     TcpStream::connect(&addr)
-          .map_err(DenoError::from)
+      .map_err(ErrBox::from)
       .and_then(move |tcp_stream| new_conn(cmd_id, tcp_stream))
   });
   if base.sync() {
@@ -1858,7 +1850,7 @@ fn op_run(
   }
 
   // Spawn the command.
-  let child = c.spawn_async().map_err(DenoError::from)?;
+  let child = c.spawn_async().map_err(ErrBox::from)?;
 
   let pid = child.id();
   let resources = resources::add_child(child);
@@ -1977,8 +1969,8 @@ fn op_worker_get_message(
   let op = GetMessageFuture {
     state: state.clone(),
   };
-  let op = op.map_err(move |_| -> DenoError { unimplemented!() });
+  let op = op.map_err(move |_| -> ErrBox { unimplemented!() });
-  let op = op.and_then(move |maybe_buf| -> DenoResult<Buf> {
+  let op = op.and_then(move |maybe_buf| -> Result<Buf, ErrBox> {
     debug!("op_worker_get_message");
     let builder = &mut FlatBufferBuilder::new();
 
@@ -2015,7 +2007,7 @@ fn op_worker_post_message(
   };
   tx.send(d)
     .wait()
-    .map_err(|e| deno_error::new(ErrorKind::Other, e.to_string()))?;
+    .map_err(|e| DenoError::new(ErrorKind::Other, e.to_string()))?;
   let builder = &mut FlatBufferBuilder::new();
 
   ok_buf(serialize_response(
@@ -2051,8 +2043,8 @@ fn op_create_worker(
 
   let mut worker =
     Worker::new(name, startup_data::deno_isolate_init(), child_state);
-  err_check(worker.execute("denoMain()"));
+  worker.execute("denoMain()").unwrap();
-  err_check(worker.execute("workerMain()"));
+  worker.execute("workerMain()").unwrap();
 
   let module_specifier = ModuleSpecifier::resolve_url_or_path(specifier)?;
 
@@ -2132,8 +2124,8 @@ fn op_host_get_message(
   let rid = inner.rid();
 
   let op = resources::get_message_from_worker(rid);
-  let op = op.map_err(move |_| -> DenoError { unimplemented!() });
+  let op = op.map_err(move |_| -> ErrBox { unimplemented!() });
-  let op = op.and_then(move |maybe_buf| -> DenoResult<Buf> {
+  let op = op.and_then(move |maybe_buf| -> Result<Buf, ErrBox> {
     let builder = &mut FlatBufferBuilder::new();
 
     let data = maybe_buf.as_ref().map(|buf| builder.create_vector(buf));
@@ -2168,7 +2160,7 @@ fn op_host_post_message(
 
   resources::post_message_to_worker(rid, d)
     .wait()
-    .map_err(|e| deno_error::new(ErrorKind::Other, e.to_string()))?;
+    .map_err(|e| DenoError::new(ErrorKind::Other, e.to_string()))?;
   let builder = &mut FlatBufferBuilder::new();
 
   ok_buf(serialize_response(

cli/permissions.rs

@@ -1,11 +1,9 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
-use atty;
-
-use crate::flags::DenoFlags;
-
 use ansi_term::Style;
+use atty;
 use crate::deno_error::permission_denied;
-use crate::deno_error::DenoResult;
+use crate::flags::DenoFlags;
+use deno::ErrBox;
 use log;
 use std::collections::HashSet;
 use std::fmt;
@@ -160,7 +158,7 @@ impl DenoPermissions {
     }
   }
 
-  pub fn check_run(&self) -> DenoResult<()> {
+  pub fn check_run(&self) -> Result<(), ErrBox> {
     let msg = "access to run a subprocess";
 
     match self.allow_run.get_state() {
@@ -181,7 +179,7 @@ impl DenoPermissions {
     }
   }
 
-  pub fn check_read(&self, filename: &str) -> DenoResult<()> {
+  pub fn check_read(&self, filename: &str) -> Result<(), ErrBox> {
     let msg = &format!("read access to \"{}\"", filename);
     match self.allow_read.get_state() {
       PermissionAccessorState::Allow => {
@@ -213,7 +211,7 @@ impl DenoPermissions {
     }
   }
 
-  pub fn check_write(&self, filename: &str) -> DenoResult<()> {
+  pub fn check_write(&self, filename: &str) -> Result<(), ErrBox> {
     let msg = &format!("write access to \"{}\"", filename);
     match self.allow_write.get_state() {
       PermissionAccessorState::Allow => {
@@ -245,7 +243,7 @@ impl DenoPermissions {
     }
   }
 
-  pub fn check_net(&self, host_and_port: &str) -> DenoResult<()> {
+  pub fn check_net(&self, host_and_port: &str) -> Result<(), ErrBox> {
     let msg = &format!("network access to \"{}\"", host_and_port);
     match self.allow_net.get_state() {
       PermissionAccessorState::Allow => {
@@ -276,7 +274,7 @@ impl DenoPermissions {
     }
   }
 
-  pub fn check_net_url(&self, url: url::Url) -> DenoResult<()> {
+  pub fn check_net_url(&self, url: url::Url) -> Result<(), ErrBox> {
     let msg = &format!("network access to \"{}\"", url);
     match self.allow_net.get_state() {
       PermissionAccessorState::Allow => {
@@ -311,7 +309,7 @@ impl DenoPermissions {
     &self,
     state: PermissionAccessorState,
     prompt_str: &str,
-  ) -> DenoResult<()> {
+  ) -> Result<(), ErrBox> {
     match state {
       PermissionAccessorState::Ask => {
         match self.try_permissions_prompt(prompt_str) {
@@ -329,7 +327,7 @@ impl DenoPermissions {
     }
   }
 
-  pub fn check_env(&self) -> DenoResult<()> {
+  pub fn check_env(&self) -> Result<(), ErrBox> {
     let msg = "access to environment variables";
     match self.allow_env.get_state() {
       PermissionAccessorState::Allow => {
@@ -351,7 +349,10 @@ impl DenoPermissions {
 
   /// Try to present the user with a permission prompt
   /// will error with permission_denied if no_prompts is enabled
-  fn try_permissions_prompt(&self, message: &str) -> DenoResult<PromptResult> {
+  fn try_permissions_prompt(
+    &self,
+    message: &str,
+  ) -> Result<PromptResult, ErrBox> {
     if self.no_prompts.load(Ordering::SeqCst) {
       return Err(permission_denied());
     }
@@ -396,31 +397,31 @@ impl DenoPermissions {
     self.allow_hrtime.is_allow()
   }
 
-  pub fn revoke_run(&self) -> DenoResult<()> {
+  pub fn revoke_run(&self) -> Result<(), ErrBox> {
     self.allow_run.revoke();
     Ok(())
   }
 
-  pub fn revoke_read(&self) -> DenoResult<()> {
+  pub fn revoke_read(&self) -> Result<(), ErrBox> {
     self.allow_read.revoke();
     Ok(())
   }
 
-  pub fn revoke_write(&self) -> DenoResult<()> {
+  pub fn revoke_write(&self) -> Result<(), ErrBox> {
     self.allow_write.revoke();
     Ok(())
   }
 
-  pub fn revoke_net(&self) -> DenoResult<()> {
+  pub fn revoke_net(&self) -> Result<(), ErrBox> {
     self.allow_net.revoke();
     Ok(())
   }
 
-  pub fn revoke_env(&self) -> DenoResult<()> {
+  pub fn revoke_env(&self) -> Result<(), ErrBox> {
     self.allow_env.revoke();
     Ok(())
   }
-  pub fn revoke_hrtime(&self) -> DenoResult<()> {
+  pub fn revoke_hrtime(&self) -> Result<(), ErrBox> {
     self.allow_hrtime.revoke();
     Ok(())
   }
@@ -437,7 +438,7 @@ pub enum PromptResult {
 
 impl PromptResult {
   /// If value is any form of deny this will error with permission_denied
-  pub fn check(&self) -> DenoResult<()> {
+  pub fn check(&self) -> Result<(), ErrBox> {
     match self {
       PromptResult::DenyOnce => Err(permission_denied()),
       PromptResult::DenyAlways => Err(permission_denied()),
@@ -457,7 +458,7 @@ impl fmt::Display for PromptResult {
   }
 }
 
-fn permission_prompt(message: &str) -> DenoResult<PromptResult> {
+fn permission_prompt(message: &str) -> Result<PromptResult, ErrBox> {
   let msg = format!("️{}  Deno requests {}. Grant? [a/y/n/d (a = allow always, y = allow once, n = deny once, d = deny always)] ", PERMISSION_EMOJI, message);
   // print to stderr so that if deno is > to a file this is still displayed.
   eprint!("{}", Style::new().bold().paint(msg));

cli/repl.rs

@@ -1,12 +1,7 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
-use rustyline;
-
-use crate::msg::ErrorKind;
-use std::error::Error;
-
 use crate::deno_dir::DenoDir;
-use crate::deno_error::new as deno_error;
+use deno::ErrBox;
-use crate::deno_error::DenoResult;
+use rustyline;
 use std::path::PathBuf;
 
 #[cfg(not(windows))]
@@ -78,25 +73,25 @@ impl Repl {
       .unwrap_or(())
   }
 
-  fn save_history(&mut self) -> DenoResult<()> {
+  fn save_history(&mut self) -> Result<(), ErrBox> {
     self
       .editor
       .save_history(&self.history_file.to_str().unwrap())
       .map(|_| debug!("Saved REPL history to: {:?}", self.history_file))
       .map_err(|e| {
         eprintln!("Unable to save REPL history: {:?} {}", self.history_file, e);
-        deno_error(ErrorKind::Other, e.description().to_string())
+        ErrBox::from(e)
       })
   }
 
-  pub fn readline(&mut self, prompt: &str) -> DenoResult<String> {
+  pub fn readline(&mut self, prompt: &str) -> Result<String, ErrBox> {
     self
       .editor
       .readline(&prompt)
       .map(|line| {
         self.editor.add_history_entry(line.clone());
         line
-      }).map_err(|e| deno_error(ErrorKind::Other, e.description().to_string()))
+      }).map_err(ErrBox::from)
     // Forward error to TS side for processing
   }
 }

cli/resolve_addr.rs

@@ -1,10 +1,9 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
-
+use crate::deno_error;
+use deno::ErrBox;
 use futures::Async;
 use futures::Future;
 use futures::Poll;
-use std::error::Error;
-use std::fmt;
 use std::net::SocketAddr;
 use std::net::ToSocketAddrs;
 
@@ -21,46 +20,23 @@ pub fn resolve_addr(address: &str) -> ResolveAddrFuture {
   }
 }
 
-#[derive(Debug)]
-pub enum ResolveAddrError {
-  Syntax,
-  Resolution(std::io::Error),
-}
-
-impl fmt::Display for ResolveAddrError {
-  fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
-    fmt.write_str(self.description())
-  }
-}
-
-impl Error for ResolveAddrError {
-  fn description(&self) -> &str {
-    match self {
-      ResolveAddrError::Syntax => "invalid address syntax",
-      ResolveAddrError::Resolution(e) => e.description(),
-    }
-  }
-}
-
 pub struct ResolveAddrFuture {
   address: String,
 }
 
 impl Future for ResolveAddrFuture {
   type Item = SocketAddr;
-  type Error = ResolveAddrError;
+  type Error = ErrBox;
 
   fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
     // The implementation of this is not actually async at the moment,
     // however we intend to use async DNS resolution in the future and
     // so we expose this as a future instead of Result.
     match split(&self.address) {
-      None => Err(ResolveAddrError::Syntax),
+      None => Err(deno_error::invalid_address_syntax()),
       Some(addr_port_pair) => {
         // I absolutely despise the .to_socket_addrs() API.
-        let r = addr_port_pair
+        let r = addr_port_pair.to_socket_addrs().map_err(ErrBox::from);
-          .to_socket_addrs()
-          .map_err(ResolveAddrError::Resolution);
 
         r.and_then(|mut iter| match iter.next() {
           Some(a) => Ok(Async::Ready(a)),

cli/resources.rs

@@ -10,13 +10,12 @@
 
 use crate::deno_error;
 use crate::deno_error::bad_resource;
-use crate::deno_error::DenoError;
-use crate::deno_error::DenoResult;
 use crate::http_body::HttpBody;
 use crate::repl::Repl;
 use crate::state::WorkerChannels;
 
 use deno::Buf;
+use deno::ErrBox;
 
 use futures;
 use futures::Future;
@@ -216,14 +215,14 @@ impl Resource {
     }
   }
 
-  pub fn shutdown(&mut self, how: Shutdown) -> Result<(), DenoError> {
+  pub fn shutdown(&mut self, how: Shutdown) -> Result<(), ErrBox> {
     let mut table = RESOURCE_TABLE.lock().unwrap();
     let maybe_repr = table.get_mut(&self.rid);
     match maybe_repr {
       None => panic!("bad rid"),
       Some(repr) => match repr {
         Repr::TcpStream(ref mut f) => {
-          TcpStream::shutdown(f, how).map_err(DenoError::from)
+          TcpStream::shutdown(f, how).map_err(ErrBox::from)
         }
         _ => panic!("Cannot shutdown"),
       },
@@ -366,15 +365,13 @@ pub struct WorkerReceiver {
 // Invert the dumbness that tokio_process causes by making Child itself a future.
 impl Future for WorkerReceiver {
   type Item = Option<Buf>;
-  type Error = DenoError;
+  type Error = ErrBox;
 
-  fn poll(&mut self) -> Poll<Option<Buf>, DenoError> {
+  fn poll(&mut self) -> Poll<Option<Buf>, ErrBox> {
     let mut table = RESOURCE_TABLE.lock().unwrap();
     let maybe_repr = table.get_mut(&self.rid);
     match maybe_repr {
-      Some(Repr::Worker(ref mut wc)) => wc.1.poll().map_err(|err| {
+      Some(Repr::Worker(ref mut wc)) => wc.1.poll().map_err(ErrBox::from),
-        deno_error::new(deno_error::ErrorKind::Other, err.to_string())
-      }),
       _ => Err(bad_resource()),
     }
   }
@@ -391,15 +388,13 @@ pub struct WorkerReceiverStream {
 // Invert the dumbness that tokio_process causes by making Child itself a future.
 impl Stream for WorkerReceiverStream {
   type Item = Buf;
-  type Error = DenoError;
+  type Error = ErrBox;
 
-  fn poll(&mut self) -> Poll<Option<Buf>, DenoError> {
+  fn poll(&mut self) -> Poll<Option<Buf>, ErrBox> {
     let mut table = RESOURCE_TABLE.lock().unwrap();
     let maybe_repr = table.get_mut(&self.rid);
     match maybe_repr {
-      Some(Repr::Worker(ref mut wc)) => wc.1.poll().map_err(|err| {
+      Some(Repr::Worker(ref mut wc)) => wc.1.poll().map_err(ErrBox::from),
-        deno_error::new(deno_error::ErrorKind::Other, err.to_string())
-      }),
       _ => Err(bad_resource()),
     }
   }
@@ -462,19 +457,19 @@ pub struct ChildStatus {
 // Invert the dumbness that tokio_process causes by making Child itself a future.
 impl Future for ChildStatus {
   type Item = ExitStatus;
-  type Error = DenoError;
+  type Error = ErrBox;
 
-  fn poll(&mut self) -> Poll<ExitStatus, DenoError> {
+  fn poll(&mut self) -> Poll<ExitStatus, ErrBox> {
     let mut table = RESOURCE_TABLE.lock().unwrap();
     let maybe_repr = table.get_mut(&self.rid);
     match maybe_repr {
-      Some(Repr::Child(ref mut child)) => child.poll().map_err(DenoError::from),
+      Some(Repr::Child(ref mut child)) => child.poll().map_err(ErrBox::from),
       _ => Err(bad_resource()),
     }
   }
 }
 
-pub fn child_status(rid: ResourceId) -> DenoResult<ChildStatus> {
+pub fn child_status(rid: ResourceId) -> Result<ChildStatus, ErrBox> {
   let mut table = RESOURCE_TABLE.lock().unwrap();
   let maybe_repr = table.get_mut(&rid);
   match maybe_repr {
@@ -483,7 +478,7 @@ pub fn child_status(rid: ResourceId) -> DenoResult<ChildStatus> {
   }
 }
 
-pub fn get_repl(rid: ResourceId) -> DenoResult<Arc<Mutex<Repl>>> {
+pub fn get_repl(rid: ResourceId) -> Result<Arc<Mutex<Repl>>, ErrBox> {
   let mut table = RESOURCE_TABLE.lock().unwrap();
   let maybe_repr = table.get_mut(&rid);
   match maybe_repr {
@@ -494,7 +489,7 @@ pub fn get_repl(rid: ResourceId) -> DenoResult<Arc<Mutex<Repl>>> {
 
 // TODO: revamp this after the following lands:
 // https://github.com/tokio-rs/tokio/pull/785
-pub fn get_file(rid: ResourceId) -> DenoResult<std::fs::File> {
+pub fn get_file(rid: ResourceId) -> Result<std::fs::File, ErrBox> {
   let mut table = RESOURCE_TABLE.lock().unwrap();
   // We take ownership of File here.
   // It is put back below while still holding the lock.
@@ -516,7 +511,7 @@ pub fn get_file(rid: ResourceId) -> DenoResult<std::fs::File> {
       table.insert(rid, Repr::FsFile(tokio_fs::File::from_std(std_file)));
 
       if maybe_std_file_copy.is_err() {
-        return Err(DenoError::from(maybe_std_file_copy.unwrap_err()));
+        return Err(ErrBox::from(maybe_std_file_copy.unwrap_err()));
       }
 
       let std_file_copy = maybe_std_file_copy.unwrap();
@@ -537,23 +532,25 @@ pub fn seek(
   resource: Resource,
   offset: i32,
   whence: u32,
-) -> Box<dyn Future<Item = (), Error = DenoError> + Send> {
+) -> Box<dyn Future<Item = (), Error = ErrBox> + Send> {
   // Translate seek mode to Rust repr.
   let seek_from = match whence {
     0 => SeekFrom::Start(offset as u64),
     1 => SeekFrom::Current(i64::from(offset)),
     2 => SeekFrom::End(i64::from(offset)),
     _ => {
-      return Box::new(futures::future::err(deno_error::new(
+      return Box::new(futures::future::err(
+        deno_error::DenoError::new(
           deno_error::ErrorKind::InvalidSeekMode,
           format!("Invalid seek mode: {}", whence),
-      )));
+        ).into(),
+      ));
     }
   };
 
   match get_file(resource.rid) {
     Ok(mut file) => Box::new(futures::future::lazy(move || {
-      let result = file.seek(seek_from).map(|_| {}).map_err(DenoError::from);
+      let result = file.seek(seek_from).map(|_| {}).map_err(ErrBox::from);
       futures::future::result(result)
     })),
     Err(err) => Box::new(futures::future::err(err)),

cli/shell.rs

@@ -10,11 +10,10 @@ use std::fmt;
 use std::io::prelude::*;
 
 use atty;
+use deno::ErrBox;
 use termcolor::Color::{Cyan, Green, Red, Yellow};
 use termcolor::{self, Color, ColorSpec, StandardStream, WriteColor};
 
-use crate::deno_error::DenoResult;
-
 /// The requested verbosity of output.
 #[derive(Debug, Clone, Copy, PartialEq)]
 pub enum Verbosity {
@@ -116,7 +115,7 @@ impl Shell {
     message: Option<&dyn fmt::Display>,
     color: Color,
     justified: bool,
-  ) -> DenoResult<()> {
+  ) -> Result<(), ErrBox> {
     match self.verbosity {
       Verbosity::Quiet => Ok(()),
       _ => {
@@ -171,7 +170,7 @@ impl Shell {
   }
 
   /// Shortcut to right-align and color green a status message.
-  pub fn status<T, U>(&mut self, status: T, message: U) -> DenoResult<()>
+  pub fn status<T, U>(&mut self, status: T, message: U) -> Result<(), ErrBox>
   where
     T: fmt::Display,
     U: fmt::Display,
@@ -179,7 +178,7 @@ impl Shell {
     self.print(&status, Some(&message), Green, false)
   }
 
-  pub fn status_header<T>(&mut self, status: T) -> DenoResult<()>
+  pub fn status_header<T>(&mut self, status: T) -> Result<(), ErrBox>
   where
     T: fmt::Display,
   {
@@ -192,7 +191,7 @@ impl Shell {
     status: T,
     message: U,
     color: Color,
-  ) -> DenoResult<()>
+  ) -> Result<(), ErrBox>
   where
     T: fmt::Display,
     U: fmt::Display,
@@ -201,9 +200,9 @@ impl Shell {
   }
 
   /// Runs the callback only if we are in verbose mode.
-  pub fn verbose<F>(&mut self, mut callback: F) -> DenoResult<()>
+  pub fn verbose<F>(&mut self, mut callback: F) -> Result<(), ErrBox>
   where
-    F: FnMut(&mut Shell) -> DenoResult<()>,
+    F: FnMut(&mut Shell) -> Result<(), ErrBox>,
   {
     match self.verbosity {
       Verbosity::Verbose => callback(self),
@@ -212,9 +211,9 @@ impl Shell {
   }
 
   /// Runs the callback if we are not in verbose mode.
-  pub fn concise<F>(&mut self, mut callback: F) -> DenoResult<()>
+  pub fn concise<F>(&mut self, mut callback: F) -> Result<(), ErrBox>
   where
-    F: FnMut(&mut Shell) -> DenoResult<()>,
+    F: FnMut(&mut Shell) -> Result<(), ErrBox>,
   {
     match self.verbosity {
       Verbosity::Verbose => Ok(()),
@@ -223,12 +222,12 @@ impl Shell {
   }
 
   /// Prints a red 'error' message.
-  pub fn error<T: fmt::Display>(&mut self, message: T) -> DenoResult<()> {
+  pub fn error<T: fmt::Display>(&mut self, message: T) -> Result<(), ErrBox> {
     self.print(&"error:", Some(&message), Red, false)
   }
 
   /// Prints an amber 'warning' message.
-  pub fn warn<T: fmt::Display>(&mut self, message: T) -> DenoResult<()> {
+  pub fn warn<T: fmt::Display>(&mut self, message: T) -> Result<(), ErrBox> {
     match self.verbosity {
       Verbosity::Quiet => Ok(()),
       _ => self.print(&"warning:", Some(&message), Yellow, false),
@@ -246,7 +245,10 @@ impl Shell {
   }
 
   /// Updates the color choice (always, never, or auto) from a string..
-  pub fn set_color_choice(&mut self, color: Option<&str>) -> DenoResult<()> {
+  pub fn set_color_choice(
+    &mut self,
+    color: Option<&str>,
+  ) -> Result<(), ErrBox> {
     if let ShellOut::Stream {
       ref mut stream,
       ref mut color_choice,
@@ -291,7 +293,7 @@ impl Shell {
   }
 
   /// Prints a message and translates ANSI escape code into console colors.
-  pub fn print_ansi(&mut self, message: &[u8]) -> DenoResult<()> {
+  pub fn print_ansi(&mut self, message: &[u8]) -> Result<(), ErrBox> {
     if self.needs_clear {
       self.err_erase_line();
     }
@@ -323,7 +325,7 @@ impl ShellOut {
     message: Option<&dyn fmt::Display>,
     color: Color,
     justified: bool,
-  ) -> DenoResult<()> {
+  ) -> Result<(), ErrBox> {
     match *self {
       ShellOut::Stream { ref mut stream, .. } => {
         stream.reset()?;

cli/signal.rs

@@ -1,19 +1,15 @@
+use deno::ErrBox;
+
 #[cfg(unix)]
+pub fn kill(pid: i32, signo: i32) -> Result<(), ErrBox> {
   use nix::sys::signal::{kill as unix_kill, Signal};
-#[cfg(unix)]
   use nix::unistd::Pid;
-
-use crate::deno_error::DenoResult;
-
-#[cfg(unix)]
-pub fn kill(pid: i32, signo: i32) -> DenoResult<()> {
-  use crate::deno_error::DenoError;
   let sig = Signal::from_c_int(signo)?;
-  unix_kill(Pid::from_raw(pid), Option::Some(sig)).map_err(DenoError::from)
+  unix_kill(Pid::from_raw(pid), Option::Some(sig)).map_err(ErrBox::from)
 }
 
 #[cfg(not(unix))]
-pub fn kill(_pid: i32, _signal: i32) -> DenoResult<()> {
+pub fn kill(_pid: i32, _signal: i32) -> Result<(), ErrBox> {
   // NOOP
   // TODO: implement this for windows
   Ok(())

cli/source_maps.rs

@@ -1,7 +1,7 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
-//! This mod provides functions to remap a deno::JSError based on a source map
+//! This mod provides functions to remap a deno::V8Exception based on a source map
-use deno::JSError;
 use deno::StackFrame;
+use deno::V8Exception;
 use serde_json;
 use source_map_mappings::parse_mappings;
 use source_map_mappings::Bias;
@@ -90,36 +90,36 @@ fn builtin_source_map(script_name: &str) -> Option<Vec<u8>> {
   }
 }
 
-/// Apply a source map to a JSError, returning a JSError where the filenames,
+/// Apply a source map to a V8Exception, returning a V8Exception where the filenames,
 /// the lines and the columns point to their original source location, not their
 /// transpiled location if applicable.
 pub fn apply_source_map<G: SourceMapGetter>(
-  js_error: &JSError,
+  v8_exception: &V8Exception,
   getter: &G,
-) -> JSError {
+) -> V8Exception {
   let mut mappings_map: CachedMaps = HashMap::new();
 
   let mut frames = Vec::<StackFrame>::new();
-  for frame in &js_error.frames {
+  for frame in &v8_exception.frames {
     let f = frame_apply_source_map(&frame, &mut mappings_map, getter);
     frames.push(f);
   }
 
   let (script_resource_name, line_number, start_column) =
     get_maybe_orig_position(
-      js_error.script_resource_name.clone(),
+      v8_exception.script_resource_name.clone(),
-      js_error.line_number,
+      v8_exception.line_number,
-      js_error.start_column,
+      v8_exception.start_column,
       &mut mappings_map,
       getter,
     );
   // It is better to just move end_column to be the same distance away from
   // start column because sometimes the code point is not available in the
   // source file map.
-  let end_column = match js_error.end_column {
+  let end_column = match v8_exception.end_column {
     Some(ec) => {
       if start_column.is_some() {
-        Some(ec - (js_error.start_column.unwrap() - start_column.unwrap()))
+        Some(ec - (v8_exception.start_column.unwrap() - start_column.unwrap()))
       } else {
         None
       }
@@ -128,22 +128,22 @@ pub fn apply_source_map<G: SourceMapGetter>(
   };
   // if there is a source line that we might be different in the source file, we
   // will go fetch it from the getter
-  let source_line = if js_error.source_line.is_some()
+  let source_line = if v8_exception.source_line.is_some()
     && script_resource_name.is_some()
     && line_number.is_some()
   {
     getter.get_source_line(
-      &js_error.script_resource_name.clone().unwrap(),
+      &v8_exception.script_resource_name.clone().unwrap(),
       line_number.unwrap() as usize,
     )
   } else {
-    js_error.source_line.clone()
+    v8_exception.source_line.clone()
   };
 
-  JSError {
+  V8Exception {
-    message: js_error.message.clone(),
+    message: v8_exception.message.clone(),
     frames,
-    error_level: js_error.error_level,
+    error_level: v8_exception.error_level,
     source_line,
     script_resource_name,
     line_number,
@@ -151,8 +151,8 @@ pub fn apply_source_map<G: SourceMapGetter>(
     end_column,
     // These are difficult to map to their original position and they are not
     // currently used in any output, so we don't remap them.
-    start_position: js_error.start_position,
+    start_position: v8_exception.start_position,
-    end_position: js_error.end_position,
+    end_position: v8_exception.end_position,
   }
 }
 
@@ -297,8 +297,8 @@ mod tests {
     }
   }
 
-  fn error1() -> JSError {
+  fn error1() -> V8Exception {
-    JSError {
+    V8Exception {
       message: "Error: foo bar".to_string(),
       source_line: None,
       script_resource_name: None,
@@ -341,11 +341,11 @@ mod tests {
   }
 
   #[test]
-  fn js_error_apply_source_map_1() {
+  fn v8_exception_apply_source_map_1() {
     let e = error1();
     let getter = MockSourceMapGetter {};
     let actual = apply_source_map(&e, &getter);
-    let expected = JSError {
+    let expected = V8Exception {
       message: "Error: foo bar".to_string(),
       source_line: None,
       script_resource_name: None,
@@ -389,8 +389,8 @@ mod tests {
   }
 
   #[test]
-  fn js_error_apply_source_map_2() {
+  fn v8_exception_apply_source_map_2() {
-    let e = JSError {
+    let e = V8Exception {
       message: "TypeError: baz".to_string(),
       source_line: None,
       script_resource_name: None,
@@ -419,8 +419,8 @@ mod tests {
   }
 
   #[test]
-  fn js_error_apply_source_map_line() {
+  fn v8_exception_apply_source_map_line() {
-    let e = JSError {
+    let e = V8Exception {
       message: "TypeError: baz".to_string(),
       source_line: Some("foo".to_string()),
       script_resource_name: Some("foo_bar.ts".to_string()),

cli/state.rs

@@ -2,8 +2,6 @@
 use crate::compiler::compile_async;
 use crate::compiler::ModuleMetaData;
 use crate::deno_dir;
-use crate::deno_error::DenoError;
-use crate::deno_error::DenoResult;
 use crate::flags;
 use crate::global_timer::GlobalTimer;
 use crate::import_map::ImportMap;
@@ -16,6 +14,7 @@ use crate::resources::ResourceId;
 use crate::worker::Worker;
 use deno::Buf;
 use deno::CoreOp;
+use deno::ErrBox;
 use deno::Loader;
 use deno::ModuleSpecifier;
 use deno::PinnedBuf;
@@ -118,7 +117,7 @@ impl ThreadSafeState {
 pub fn fetch_module_meta_data_and_maybe_compile_async(
   state: &ThreadSafeState,
   module_specifier: &ModuleSpecifier,
-) -> impl Future<Item = ModuleMetaData, Error = DenoError> {
+) -> impl Future<Item = ModuleMetaData, Error = ErrBox> {
   let state_ = state.clone();
   let use_cache =
     !state_.flags.reload || state_.has_compiled(&module_specifier.to_string());
@@ -150,14 +149,12 @@ pub fn fetch_module_meta_data_and_maybe_compile_async(
 }
 
 impl Loader for ThreadSafeState {
-  type Error = DenoError;
-
   fn resolve(
     &self,
     specifier: &str,
     referrer: &str,
     is_root: bool,
-  ) -> Result<ModuleSpecifier, Self::Error> {
+  ) -> Result<ModuleSpecifier, ErrBox> {
     if !is_root {
       if let Some(import_map) = &self.import_map {
         let result = import_map.resolve(specifier, referrer)?;
@@ -167,15 +164,14 @@ impl Loader for ThreadSafeState {
       }
     }
 
-    ModuleSpecifier::resolve_import(specifier, referrer)
+    ModuleSpecifier::resolve_import(specifier, referrer).map_err(ErrBox::from)
-      .map_err(DenoError::from)
   }
 
   /// Given an absolute url, load its source code.
   fn load(
     &self,
     module_specifier: &ModuleSpecifier,
-  ) -> Box<deno::SourceCodeInfoFuture<Self::Error>> {
+  ) -> Box<deno::SourceCodeInfoFuture> {
     self.metrics.resolve_count.fetch_add(1, Ordering::SeqCst);
     Box::new(
       fetch_module_meta_data_and_maybe_compile_async(self, module_specifier)
@@ -324,32 +320,32 @@ impl ThreadSafeState {
   }
 
   #[inline]
-  pub fn check_read(&self, filename: &str) -> DenoResult<()> {
+  pub fn check_read(&self, filename: &str) -> Result<(), ErrBox> {
     self.permissions.check_read(filename)
   }
 
   #[inline]
-  pub fn check_write(&self, filename: &str) -> DenoResult<()> {
+  pub fn check_write(&self, filename: &str) -> Result<(), ErrBox> {
     self.permissions.check_write(filename)
   }
 
   #[inline]
-  pub fn check_env(&self) -> DenoResult<()> {
+  pub fn check_env(&self) -> Result<(), ErrBox> {
     self.permissions.check_env()
   }
 
   #[inline]
-  pub fn check_net(&self, host_and_port: &str) -> DenoResult<()> {
+  pub fn check_net(&self, host_and_port: &str) -> Result<(), ErrBox> {
     self.permissions.check_net(host_and_port)
   }
 
   #[inline]
-  pub fn check_net_url(&self, url: url::Url) -> DenoResult<()> {
+  pub fn check_net_url(&self, url: url::Url) -> Result<(), ErrBox> {
     self.permissions.check_net_url(url)
   }
 
   #[inline]
-  pub fn check_run(&self) -> DenoResult<()> {
+  pub fn check_run(&self) -> Result<(), ErrBox> {
     self.permissions.check_run()
   }
 

cli/worker.rs

@@ -1,8 +1,9 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
-use crate::deno_error::DenoError;
+use crate::fmt_errors::JSError;
 use crate::state::ThreadSafeState;
 use crate::tokio_util;
 use deno;
+use deno::ErrBox;
 use deno::ModuleSpecifier;
 use deno::StartupData;
 use futures::Async;
@@ -24,19 +25,23 @@ impl Worker {
     startup_data: StartupData,
     state: ThreadSafeState,
   ) -> Worker {
-    let state_ = state.clone();
     let isolate = Arc::new(Mutex::new(deno::Isolate::new(startup_data, false)));
     {
       let mut i = isolate.lock().unwrap();
+      let state_ = state.clone();
       i.set_dispatch(move |control_buf, zero_copy_buf| {
         state_.dispatch(control_buf, zero_copy_buf)
       });
+      let state_ = state.clone();
+      i.set_js_error_create(move |v8_exception| {
+        JSError::from_v8_exception(v8_exception, &state_.dir)
+      })
     }
     Self { isolate, state }
   }
 
   /// Same as execute2() but the filename defaults to "<anonymous>".
-  pub fn execute(&mut self, js_source: &str) -> Result<(), DenoError> {
+  pub fn execute(&mut self, js_source: &str) -> Result<(), ErrBox> {
     self.execute2("<anonymous>", js_source)
   }
 
@@ -46,12 +51,9 @@ impl Worker {
     &mut self,
     js_filename: &str,
     js_source: &str,
-  ) -> Result<(), DenoError> {
+  ) -> Result<(), ErrBox> {
     let mut isolate = self.isolate.lock().unwrap();
-    match isolate.execute(js_filename, js_source) {
+    isolate.execute(js_filename, js_source)
-      Ok(_) => Ok(()),
-      Err(err) => Err(DenoError::from(err)),
-    }
   }
 
   /// Executes the provided JavaScript module.
@@ -59,9 +61,8 @@ impl Worker {
     &mut self,
     module_specifier: &ModuleSpecifier,
     is_prefetch: bool,
-  ) -> impl Future<Item = (), Error = DenoError> {
+  ) -> impl Future<Item = (), Error = ErrBox> {
     let worker = self.clone();
-    let worker_ = worker.clone();
     let loader = self.state.clone();
     let isolate = self.isolate.clone();
     let modules = self.state.modules.clone();
@@ -71,28 +72,13 @@ impl Worker {
       isolate,
       modules,
     );
-    recursive_load
+    recursive_load.and_then(move |id| -> Result<(), ErrBox> {
-      .and_then(move |id| -> Result<(), deno::JSErrorOr<DenoError>> {
       worker.state.progress.done();
       if is_prefetch {
         Ok(())
       } else {
         let mut isolate = worker.isolate.lock().unwrap();
-          let result = isolate.mod_evaluate(id);
+        isolate.mod_evaluate(id)
-          if let Err(err) = result {
-            Err(deno::JSErrorOr::JSError(err))
-          } else {
-            Ok(())
-          }
-        }
-      }).map_err(move |err| {
-        worker_.state.progress.done();
-        // Convert to DenoError AND apply_source_map.
-        match err {
-          deno::JSErrorOr::JSError(err) => {
-            worker_.apply_source_map(DenoError::from(err))
-          }
-          deno::JSErrorOr::Other(err) => err,
       }
     })
   }
@@ -102,32 +88,24 @@ impl Worker {
     &mut self,
     module_specifier: &ModuleSpecifier,
     is_prefetch: bool,
-  ) -> Result<(), DenoError> {
+  ) -> Result<(), ErrBox> {
     tokio_util::block_on(self.execute_mod_async(module_specifier, is_prefetch))
   }
-
-  /// Applies source map to the error.
-  fn apply_source_map(&self, err: DenoError) -> DenoError {
-    err.apply_source_map(&self.state.dir)
-  }
 }
 
 impl Future for Worker {
   type Item = ();
-  type Error = DenoError;
+  type Error = ErrBox;
 
-  fn poll(&mut self) -> Result<Async<()>, Self::Error> {
+  fn poll(&mut self) -> Result<Async<()>, ErrBox> {
     let mut isolate = self.isolate.lock().unwrap();
-    isolate
+    isolate.poll()
-      .poll()
-      .map_err(|err| self.apply_source_map(DenoError::from(err)))
   }
 }
 
 #[cfg(test)]
 mod tests {
   use super::*;
-  use crate::deno_error::err_check;
   use crate::flags;
   use crate::ops::op_selector_std;
   use crate::progress::Progress;
@@ -210,7 +188,7 @@ mod tests {
         startup_data::deno_isolate_init(),
         state,
       );
-      err_check(worker.execute("denoMain()"));
+      worker.execute("denoMain()").unwrap();
       let result = worker.execute_mod(&module_specifier, false);
       if let Err(err) = result {
         eprintln!("execute_mod err {:?}", err);
@@ -231,8 +209,8 @@ mod tests {
     ]);
     let mut worker =
       Worker::new("TEST".to_string(), startup_data::deno_isolate_init(), state);
-    err_check(worker.execute("denoMain()"));
+    worker.execute("denoMain()").unwrap();
-    err_check(worker.execute("workerMain()"));
+    worker.execute("workerMain()").unwrap();
     worker
   }
 
@@ -253,7 +231,7 @@ mod tests {
           console.log("after postMessage");
         }
         "#;
-      err_check(worker.execute(source));
+      worker.execute(source).unwrap();
 
       let resource = worker.state.resource.clone();
       let resource_ = resource.clone();
@@ -261,7 +239,7 @@ mod tests {
       tokio::spawn(lazy(move || {
         worker.then(move |r| -> Result<(), ()> {
           resource_.close();
-          err_check(r);
+          r.unwrap();
           Ok(())
         })
       }));
@@ -291,9 +269,9 @@ mod tests {
   fn removed_from_resource_table_on_close() {
     tokio_util::init(|| {
       let mut worker = create_test_worker();
-      err_check(
+      worker
-        worker.execute("onmessage = () => { delete window.onmessage; }"),
+        .execute("onmessage = () => { delete window.onmessage; }")
-      );
+        .unwrap();
 
       let resource = worker.state.resource.clone();
       let rid = resource.rid;
@@ -302,7 +280,7 @@ mod tests {
         .then(move |r| -> Result<(), ()> {
           resource.close();
           println!("workers.rs after resource close");
-          err_check(r);
+          r.unwrap();
           Ok(())
         }).shared();
 

core/any_error.rs

@@ -0,0 +1,68 @@
+use std::any::{Any, TypeId};
+use std::convert::From;
+use std::error::Error;
+use std::fmt;
+use std::ops::Deref;
+
+// The Send and Sync traits are required because deno is multithreaded and we
+// need to beable to handle errors across threads.
+pub trait AnyError: Any + Error + Send + Sync + 'static {}
+impl<T> AnyError for T where T: Any + Error + Send + Sync + Sized + 'static {}
+
+#[derive(Debug)]
+pub struct ErrBox(Box<dyn AnyError>);
+
+impl dyn AnyError {
+  pub fn downcast_ref<T: AnyError>(&self) -> Option<&T> {
+    if Any::type_id(self) == TypeId::of::<T>() {
+      let target = self as *const Self as *const T;
+      let target = unsafe { &*target };
+      Some(target)
+    } else {
+      None
+    }
+  }
+}
+
+impl ErrBox {
+  pub fn downcast<T: AnyError>(self) -> Result<T, Self> {
+    if Any::type_id(&*self.0) == TypeId::of::<T>() {
+      let target = Box::into_raw(self.0) as *mut T;
+      let target = unsafe { Box::from_raw(target) };
+      Ok(*target)
+    } else {
+      Err(self)
+    }
+  }
+}
+
+impl AsRef<dyn AnyError> for ErrBox {
+  fn as_ref(&self) -> &dyn AnyError {
+    self.0.as_ref()
+  }
+}
+
+impl Deref for ErrBox {
+  type Target = Box<AnyError>;
+  fn deref(&self) -> &Self::Target {
+    &self.0
+  }
+}
+
+impl<T: AnyError> From<T> for ErrBox {
+  fn from(error: T) -> Self {
+    Self(Box::new(error))
+  }
+}
+
+impl From<Box<dyn AnyError>> for ErrBox {
+  fn from(boxed: Box<dyn AnyError>) -> Self {
+    Self(boxed)
+  }
+}
+
+impl fmt::Display for ErrBox {
+  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    self.0.fmt(f)
+  }
+}

core/examples/http_bench.rs

@@ -310,7 +310,7 @@ fn op_write(rid: i32, zero_copy_buf: Option<PinnedBuf>) -> Box<HttpBenchOp> {
   )
 }
 
-fn js_check(r: Result<(), JSError>) {
+fn js_check(r: Result<(), ErrBox>) {
   if let Err(e) = r {
     panic!(e.to_string());
   }

core/isolate.rs

@@ -4,7 +4,9 @@
 // isolate to keep the Isolate struct from becoming too bloating for users who
 // do not need asynchronous module loading.
 
-use crate::js_errors::JSError;
+use crate::any_error::ErrBox;
+use crate::js_errors::CoreJSError;
+use crate::js_errors::V8Exception;
 use crate::libdeno;
 use crate::libdeno::deno_buf;
 use crate::libdeno::deno_dyn_import_id;
@@ -81,6 +83,8 @@ type CoreDispatchFn = dyn Fn(&[u8], Option<PinnedBuf>) -> CoreOp;
 pub type DynImportFuture = Box<dyn Future<Item = deno_mod, Error = ()> + Send>;
 type DynImportFn = dyn Fn(&str, &str) -> DynImportFuture;
 
+type JSErrorCreateFn = dyn Fn(V8Exception) -> ErrBox;
+
 /// Wraps DynImportFuture to include the deno_dyn_import_id, so that it doesn't
 /// need to be exposed.
 struct DynImport {
@@ -114,6 +118,7 @@ pub struct Isolate {
   shared_libdeno_isolate: Arc<Mutex<Option<*const libdeno::isolate>>>,
   dispatch: Option<Arc<CoreDispatchFn>>,
   dyn_import: Option<Arc<DynImportFn>>,
+  js_error_create: Arc<JSErrorCreateFn>,
   needs_init: bool,
   shared: SharedQueue,
   pending_ops: FuturesUnordered<CoreOpAsyncFuture>,
@@ -178,6 +183,7 @@ impl Isolate {
       shared_libdeno_isolate: Arc::new(Mutex::new(Some(libdeno_isolate))),
       dispatch: None,
       dyn_import: None,
+      js_error_create: Arc::new(CoreJSError::from_v8_exception),
       shared,
       needs_init,
       pending_ops: FuturesUnordered::new(),
@@ -204,6 +210,16 @@ impl Isolate {
     self.dyn_import = Some(Arc::new(f));
   }
 
+  /// Allows a callback to be set whenever a V8 exception is made. This allows
+  /// the caller to wrap the V8Exception into an error. By default this callback
+  /// is set to CoreJSError::from_v8_exception.
+  pub fn set_js_error_create<F>(&mut self, f: F)
+  where
+    F: Fn(V8Exception) -> ErrBox + 'static,
+  {
+    self.js_error_create = Arc::new(f);
+  }
+
   /// Get a thread safe handle on the isolate.
   pub fn shared_isolate_handle(&mut self) -> IsolateHandle {
     IsolateHandle {
@@ -307,11 +323,16 @@ impl Isolate {
     self as *const _ as *const c_void
   }
 
+  /// Executes traditional JavaScript code (traditional = not ES modules)
+  ///
+  /// ErrBox can be downcast to a type that exposes additional information about
+  /// the V8 exception. By default this type is CoreJSError, however it may be a
+  /// different type if Isolate::set_js_error_create() has been used.
   pub fn execute(
     &mut self,
     js_filename: &str,
     js_source: &str,
-  ) -> Result<(), JSError> {
+  ) -> Result<(), ErrBox> {
     self.shared_init();
     let filename = CString::new(js_filename).unwrap();
     let source = CString::new(js_source).unwrap();
@@ -323,22 +344,20 @@ impl Isolate {
         source.as_ptr(),
       )
     };
-    if let Some(err) = self.last_exception() {
+    self.check_last_exception()
-      return Err(err);
-    }
-    Ok(())
   }
 
-  fn last_exception(&self) -> Option<JSError> {
+  fn check_last_exception(&self) -> Result<(), ErrBox> {
     let ptr = unsafe { libdeno::deno_last_exception(self.libdeno_isolate) };
     if ptr.is_null() {
-      None
+      Ok(())
     } else {
+      let js_error_create = &*self.js_error_create;
       let cstr = unsafe { CStr::from_ptr(ptr) };
-      let v8_exception = cstr.to_str().unwrap();
+      let json_str = cstr.to_str().unwrap();
-      debug!("v8_exception\n{}\n", v8_exception);
+      let v8_exception = V8Exception::from_json(json_str).unwrap();
-      let js_error = JSError::from_v8_exception(v8_exception).unwrap();
+      let js_error = js_error_create(v8_exception);
-      Some(js_error)
+      Err(js_error)
     }
   }
 
@@ -348,7 +367,7 @@ impl Isolate {
     }
   }
 
-  fn respond(&mut self, maybe_buf: Option<&[u8]>) -> Result<(), JSError> {
+  fn respond(&mut self, maybe_buf: Option<&[u8]>) -> Result<(), ErrBox> {
     let buf = match maybe_buf {
       None => deno_buf::empty(),
       Some(r) => deno_buf::from(r),
@@ -356,11 +375,7 @@ impl Isolate {
     unsafe {
       libdeno::deno_respond(self.libdeno_isolate, self.as_raw_ptr(), buf)
     }
-    if let Some(err) = self.last_exception() {
+    self.check_last_exception()
-      Err(err)
-    } else {
-      Ok(())
-    }
   }
 
   /// Low-level module creation.
@@ -369,7 +384,7 @@ impl Isolate {
     main: bool,
     name: &str,
     source: &str,
-  ) -> Result<deno_mod, JSError> {
+  ) -> Result<deno_mod, ErrBox> {
     let name_ = CString::new(name.to_string()).unwrap();
     let name_ptr = name_.as_ptr() as *const libc::c_char;
 
@@ -379,12 +394,11 @@ impl Isolate {
     let id = unsafe {
       libdeno::deno_mod_new(self.libdeno_isolate, main, name_ptr, source_ptr)
     };
-    if let Some(js_error) = self.last_exception() {
-      assert_eq!(id, 0);
-      return Err(js_error);
-    }
 
-    Ok(id)
+    self.check_last_exception().map(|_| id).map_err(|err| {
+      assert_eq!(id, 0);
+      err
+    })
   }
 
   pub fn mod_get_imports(&self, id: deno_mod) -> Vec<String> {
@@ -402,23 +416,29 @@ impl Isolate {
     out
   }
 
-  pub fn snapshot(&self) -> Result<Snapshot1<'static>, JSError> {
+  /// Takes a snapshot. The isolate should have been created with will_snapshot
+  /// set to true.
+  ///
+  /// ErrBox can be downcast to a type that exposes additional information about
+  /// the V8 exception. By default this type is CoreJSError, however it may be a
+  /// different type if Isolate::set_js_error_create() has been used.
+  pub fn snapshot(&self) -> Result<Snapshot1<'static>, ErrBox> {
     let snapshot = unsafe { libdeno::deno_snapshot_new(self.libdeno_isolate) };
-    if let Some(js_error) = self.last_exception() {
+    match self.check_last_exception() {
+      Ok(..) => Ok(snapshot),
+      Err(err) => {
         assert_eq!(snapshot.data_ptr, null());
         assert_eq!(snapshot.data_len, 0);
-      return Err(js_error);
+        Err(err)
+      }
     }
-    assert_ne!(snapshot.data_ptr, null());
-    assert_ne!(snapshot.data_len, 0);
-    Ok(snapshot)
   }
 
   fn dyn_import_done(
     &self,
     id: libdeno::deno_dyn_import_id,
     mod_id: deno_mod,
-  ) -> Result<(), JSError> {
+  ) -> Result<(), ErrBox> {
     debug!("dyn_import_done {} {}", id, mod_id);
     unsafe {
       libdeno::deno_dyn_import(
@@ -428,11 +448,10 @@ impl Isolate {
         mod_id,
       )
     };
-    if let Some(js_error) = self.last_exception() {
+    self.check_last_exception().map_err(|err| {
       assert_eq!(id, 0);
-      return Err(js_error);
+      err
-    }
+    })
-    Ok(())
   }
 }
 
@@ -458,11 +477,16 @@ impl<'a> ResolveContext<'a> {
 }
 
 impl Isolate {
+  /// Instanciates a ES module
+  ///
+  /// ErrBox can be downcast to a type that exposes additional information about
+  /// the V8 exception. By default this type is CoreJSError, however it may be a
+  /// different type if Isolate::set_js_error_create() has been used.
   pub fn mod_instantiate(
     &mut self,
     id: deno_mod,
     resolve_fn: &mut ResolveFn,
-  ) -> Result<(), JSError> {
+  ) -> Result<(), ErrBox> {
     let libdeno_isolate = self.libdeno_isolate;
     let mut ctx = ResolveContext { resolve_fn };
     unsafe {
@@ -473,11 +497,7 @@ impl Isolate {
         Self::resolve_cb,
       )
     };
-
+    self.check_last_exception()
-    if let Some(js_error) = self.last_exception() {
-      return Err(js_error);
-    }
-    Ok(())
   }
 
   /// Called during mod_instantiate() only.
@@ -494,15 +514,17 @@ impl Isolate {
     resolve_fn(specifier, referrer)
   }
 
-  pub fn mod_evaluate(&mut self, id: deno_mod) -> Result<(), JSError> {
+  /// Evaluates an already instantiated ES module.
+  ///
+  /// ErrBox can be downcast to a type that exposes additional information about
+  /// the V8 exception. By default this type is CoreJSError, however it may be a
+  /// different type if Isolate::set_js_error_create() has been used.
+  pub fn mod_evaluate(&mut self, id: deno_mod) -> Result<(), ErrBox> {
     self.shared_init();
     unsafe {
       libdeno::deno_mod_evaluate(self.libdeno_isolate, self.as_raw_ptr(), id)
     };
-    if let Some(js_error) = self.last_exception() {
+    self.check_last_exception()
-      return Err(js_error);
-    }
-    Ok(())
   }
 }
 
@@ -525,9 +547,9 @@ impl Drop for LockerScope {
 
 impl Future for Isolate {
   type Item = ();
-  type Error = JSError;
+  type Error = ErrBox;
 
-  fn poll(&mut self) -> Poll<(), JSError> {
+  fn poll(&mut self) -> Poll<(), ErrBox> {
     // Lock the current thread for V8.
     let _locker = LockerScope::new(self.libdeno_isolate);
 
@@ -579,9 +601,7 @@ impl Future for Isolate {
     }
 
     self.check_promise_errors();
-    if let Some(err) = self.last_exception() {
+    self.check_last_exception()?;
-      return Err(err);
-    }
 
     // We're idle if pending_ops is empty.
     if self.pending_ops.is_empty() {
@@ -616,7 +636,7 @@ impl IsolateHandle {
   }
 }
 
-pub fn js_check(r: Result<(), JSError>) {
+pub fn js_check(r: Result<(), ErrBox>) {
   if let Err(e) = r {
     panic!(e.to_string());
   }
@@ -814,7 +834,7 @@ pub mod tests {
         "#,
       ));
       assert_eq!(dispatch_count.load(Ordering::Relaxed), 1);
-      assert_eq!(Ok(Async::Ready(())), isolate.poll());
+      assert_eq!(Async::Ready(()), isolate.poll().unwrap());
       assert_eq!(dispatch_count.load(Ordering::Relaxed), 1);
       js_check(isolate.execute(
         "check2.js",
@@ -825,11 +845,11 @@ pub mod tests {
         "#,
       ));
       assert_eq!(dispatch_count.load(Ordering::Relaxed), 2);
-      assert_eq!(Ok(Async::Ready(())), isolate.poll());
+      assert_eq!(Async::Ready(()), isolate.poll().unwrap());
       js_check(isolate.execute("check3.js", "assert(nrecv == 2)"));
       assert_eq!(dispatch_count.load(Ordering::Relaxed), 2);
       // We are idle, so the next poll should be the last.
-      assert_eq!(Ok(Async::Ready(())), isolate.poll());
+      assert_eq!(Async::Ready(()), isolate.poll().unwrap());
     });
   }
 
@@ -865,7 +885,7 @@ pub mod tests {
         "#,
       ));
       assert_eq!(dispatch_count.load(Ordering::Relaxed), 2);
-      assert_eq!(Ok(Async::Ready(())), isolate.poll());
+      assert_eq!(Async::Ready(()), isolate.poll().unwrap());
       js_check(isolate.execute("send1.js", "assert(nrecv === 2);"));
     });
   }
@@ -949,9 +969,9 @@ pub mod tests {
       ));
 
       assert_eq!(count.load(Ordering::Relaxed), 1);
-      assert_eq!(Ok(Ready(())), isolate.poll());
+      assert_eq!(Ready(()), isolate.poll().unwrap());
       assert_eq!(count.load(Ordering::Relaxed), 2);
-      assert_eq!(Ok(Ready(())), isolate.poll());
+      assert_eq!(Ready(()), isolate.poll().unwrap());
       assert_eq!(count.load(Ordering::Relaxed), 2);
     })
   }
@@ -1090,7 +1110,7 @@ pub mod tests {
         "#,
       ));
       assert_eq!(dispatch_count.load(Ordering::Relaxed), 1);
-      assert_eq!(Ok(Async::Ready(())), isolate.poll());
+      assert_eq!(Async::Ready(()), isolate.poll().unwrap());
       js_check(isolate.execute("check.js", "assert(asyncRecv == 1);"));
     });
   }
@@ -1118,7 +1138,7 @@ pub mod tests {
         "#,
       ));
       assert_eq!(dispatch_count.load(Ordering::Relaxed), 1);
-      assert_eq!(Ok(()), poll_until_ready(&mut isolate, 3));
+      poll_until_ready(&mut isolate, 3).unwrap();
       js_check(isolate.execute("check.js", "assert(asyncRecv == 1);"));
     });
   }
@@ -1149,7 +1169,7 @@ pub mod tests {
         "#,
       ));
       assert_eq!(dispatch_count.load(Ordering::Relaxed), 2);
-      assert_eq!(Ok(()), poll_until_ready(&mut isolate, 3));
+      poll_until_ready(&mut isolate, 3).unwrap();
       js_check(isolate.execute("check.js", "assert(asyncRecv == 2);"));
     });
   }
@@ -1164,7 +1184,7 @@ pub mod tests {
           include_str!("shared_queue_test.js"),
         ),
       );
-      assert_eq!(Ok(Async::Ready(())), isolate.poll());
+      assert_eq!(Async::Ready(()), isolate.poll().unwrap());
     });
   }
 

core/js_errors.rs

@@ -9,8 +9,10 @@
 //   console.log(err.stack);
 // It would require calling into Rust from Error.prototype.prepareStackTrace.
 
+use crate::any_error::ErrBox;
 use serde_json;
 use serde_json::value::Value;
+use std::error::Error;
 use std::fmt;
 use std::str;
 
@@ -26,7 +28,7 @@ pub struct StackFrame {
 }
 
 #[derive(Debug, PartialEq, Clone)]
-pub struct JSError {
+pub struct V8Exception {
   pub message: String,
 
   pub source_line: Option<String>,
@@ -41,77 +43,8 @@ pub struct JSError {
   pub frames: Vec<StackFrame>,
 }
 
-impl std::error::Error for JSError {
+#[derive(Debug, PartialEq, Clone)]
-  fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+pub struct CoreJSError(V8Exception);
-    None
-  }
-}
-
-impl fmt::Display for StackFrame {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-    // Note when we print to string, we change from 0-indexed to 1-indexed.
-    let function_name = self.function_name.clone();
-    let script_line_column =
-      format_script_line_column(&self.script_name, self.line, self.column);
-
-    if !self.function_name.is_empty() {
-      write!(f, "    at {} ({})", function_name, script_line_column)
-    } else if self.is_eval {
-      write!(f, "    at eval ({})", script_line_column)
-    } else {
-      write!(f, "    at {}", script_line_column)
-    }
-  }
-}
-
-fn format_script_line_column(
-  script_name: &str,
-  line: i64,
-  column: i64,
-) -> String {
-  // TODO match this style with how typescript displays errors.
-  let line = (1 + line).to_string();
-  let column = (1 + column).to_string();
-  let script_name = script_name.to_string();
-  format!("{}:{}:{}", script_name, line, column)
-}
-
-impl fmt::Display for JSError {
-  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-    if self.script_resource_name.is_some() {
-      let script_resource_name = self.script_resource_name.as_ref().unwrap();
-      if self.line_number.is_some() && self.start_column.is_some() {
-        assert!(self.line_number.is_some());
-        assert!(self.start_column.is_some());
-        let script_line_column = format_script_line_column(
-          script_resource_name,
-          self.line_number.unwrap() - 1,
-          self.start_column.unwrap() - 1,
-        );
-        write!(f, "{}", script_line_column)?;
-      }
-      if self.source_line.is_some() {
-        write!(f, "\n{}\n", self.source_line.as_ref().unwrap())?;
-        let mut s = String::new();
-        for i in 0..self.end_column.unwrap() {
-          if i >= self.start_column.unwrap() {
-            s.push('^');
-          } else {
-            s.push(' ');
-          }
-        }
-        writeln!(f, "{}", s)?;
-      }
-    }
-
-    write!(f, "{}", self.message.clone())?;
-
-    for frame in &self.frames {
-      write!(f, "\n{}", &frame.to_string())?;
-    }
-    Ok(())
-  }
-}
 
 impl StackFrame {
   // TODO Maybe use serde_derive?
@@ -186,9 +119,9 @@ impl StackFrame {
   }
 }
 
-impl JSError {
+impl V8Exception {
-  /// Creates a new JSError by parsing the raw exception JSON string from V8.
+  /// Creates a new V8Exception by parsing the raw exception JSON string from V8.
-  pub fn from_v8_exception(json_str: &str) -> Option<Self> {
+  pub fn from_json(json_str: &str) -> Option<Self> {
     let v = serde_json::from_str::<serde_json::Value>(json_str);
     if v.is_err() {
       return None;
@@ -236,7 +169,7 @@ impl JSError {
       }
     }
 
-    Some(JSError {
+    Some(V8Exception {
       message,
       source_line,
       script_resource_name,
@@ -251,12 +184,79 @@ impl JSError {
   }
 }
 
+impl CoreJSError {
+  pub fn from_v8_exception(v8_exception: V8Exception) -> ErrBox {
+    let error = Self(v8_exception);
+    ErrBox::from(error)
+  }
+}
+
+fn format_source_loc(script_name: &str, line: i64, column: i64) -> String {
+  // TODO match this style with how typescript displays errors.
+  let line = line + 1;
+  let column = column + 1;
+  format!("{}:{}:{}", script_name, line, column)
+}
+
+fn format_stack_frame(frame: &StackFrame) -> String {
+  // Note when we print to string, we change from 0-indexed to 1-indexed.
+  let source_loc =
+    format_source_loc(&frame.script_name, frame.line, frame.column);
+
+  if !frame.function_name.is_empty() {
+    format!("    at {} ({})", frame.function_name, source_loc)
+  } else if frame.is_eval {
+    format!("    at eval ({})", source_loc)
+  } else {
+    format!("    at {}", source_loc)
+  }
+}
+
+impl fmt::Display for CoreJSError {
+  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+    if self.0.script_resource_name.is_some() {
+      let script_resource_name = self.0.script_resource_name.as_ref().unwrap();
+      if self.0.line_number.is_some() && self.0.start_column.is_some() {
+        assert!(self.0.line_number.is_some());
+        assert!(self.0.start_column.is_some());
+        let source_loc = format_source_loc(
+          script_resource_name,
+          self.0.line_number.unwrap() - 1,
+          self.0.start_column.unwrap() - 1,
+        );
+        write!(f, "{}", source_loc)?;
+      }
+      if self.0.source_line.is_some() {
+        write!(f, "\n{}\n", self.0.source_line.as_ref().unwrap())?;
+        let mut s = String::new();
+        for i in 0..self.0.end_column.unwrap() {
+          if i >= self.0.start_column.unwrap() {
+            s.push('^');
+          } else {
+            s.push(' ');
+          }
+        }
+        writeln!(f, "{}", s)?;
+      }
+    }
+
+    write!(f, "{}", self.0.message)?;
+
+    for frame in &self.0.frames {
+      write!(f, "\n{}", format_stack_frame(frame))?;
+    }
+    Ok(())
+  }
+}
+
+impl Error for CoreJSError {}
+
 #[cfg(test)]
 mod tests {
   use super::*;
 
-  fn error1() -> JSError {
+  fn error1() -> V8Exception {
-    JSError {
+    V8Exception {
       message: "Error: foo bar".to_string(),
       source_line: None,
       script_resource_name: None,
@@ -344,8 +344,8 @@ mod tests {
   }
 
   #[test]
-  fn js_error_from_v8_exception() {
+  fn v8_exception_from_json() {
-    let r = JSError::from_v8_exception(
+    let r = V8Exception::from_json(
       r#"{
         "message":"Uncaught Error: bad",
         "frames":[
@@ -387,8 +387,8 @@ mod tests {
   }
 
   #[test]
-  fn js_error_from_v8_exception2() {
+  fn v8_exception_from_json_2() {
-    let r = JSError::from_v8_exception(
+    let r = V8Exception::from_json(
       "{\"message\":\"Error: boo\",\"sourceLine\":\"throw Error('boo');\",\"scriptResourceName\":\"a.js\",\"lineNumber\":3,\"startPosition\":8,\"endPosition\":9,\"errorLevel\":8,\"startColumn\":6,\"endColumn\":7,\"isSharedCrossOrigin\":false,\"isOpaque\":false,\"frames\":[{\"line\":3,\"column\":7,\"functionName\":\"\",\"scriptName\":\"a.js\",\"isEval\":false,\"isConstructor\":false,\"isWasm\":false}]}"
     );
     assert!(r.is_some());
@@ -405,16 +405,9 @@ mod tests {
     assert_eq!(e.frames.len(), 1);
   }
 
-  #[test]
-  fn stack_frame_to_string() {
-    let e = error1();
-    assert_eq!("    at foo (foo_bar.ts:5:17)", &e.frames[0].to_string());
-    assert_eq!("    at qat (bar_baz.ts:6:21)", &e.frames[1].to_string());
-  }
-
   #[test]
   fn js_error_to_string() {
-    let e = error1();
+    let e = CoreJSError(error1());
     let expected = "Error: foo bar\n    at foo (foo_bar.ts:5:17)\n    at qat (bar_baz.ts:6:21)\n    at deno_main.js:2:2";
     assert_eq!(expected, &e.to_string());
   }

core/lib.rs

@@ -4,6 +4,7 @@ extern crate log;
 extern crate futures;
 extern crate libc;
 
+mod any_error;
 mod flags;
 mod isolate;
 mod js_errors;
@@ -12,6 +13,7 @@ mod module_specifier;
 mod modules;
 mod shared_queue;
 
+pub use crate::any_error::*;
 pub use crate::flags::v8_set_flags;
 pub use crate::isolate::*;
 pub use crate::js_errors::*;

core/modules.rs

@@ -6,8 +6,8 @@
 // small and simple for users who do not use modules or if they do can load them
 // synchronously. The isolate.rs module should never depend on this module.
 
+use crate::any_error::ErrBox;
 use crate::isolate::Isolate;
-use crate::js_errors::JSError;
 use crate::libdeno::deno_mod;
 use crate::module_specifier::ModuleSpecifier;
 use futures::Async;
@@ -15,7 +15,6 @@ use futures::Future;
 use futures::Poll;
 use std::collections::HashMap;
 use std::collections::HashSet;
-use std::error::Error;
 use std::fmt;
 use std::marker::PhantomData;
 use std::sync::Arc;
@@ -34,12 +33,10 @@ pub struct SourceCodeInfo {
   pub code: String,
 }
 
-pub type SourceCodeInfoFuture<E> =
+pub type SourceCodeInfoFuture =
-  dyn Future<Item = SourceCodeInfo, Error = E> + Send;
+  dyn Future<Item = SourceCodeInfo, Error = ErrBox> + Send;
 
 pub trait Loader: Send + Sync {
-  type Error: std::error::Error + 'static;
-
   /// Returns an absolute URL.
   /// When implementing an spec-complaint VM, this should be exactly the
   /// algorithm described here:
@@ -49,19 +46,19 @@ pub trait Loader: Send + Sync {
     specifier: &str,
     referrer: &str,
     is_root: bool,
-  ) -> Result<ModuleSpecifier, Self::Error>;
+  ) -> Result<ModuleSpecifier, ErrBox>;
 
   /// Given ModuleSpecifier, load its source code.
   fn load(
     &self,
     module_specifier: &ModuleSpecifier,
-  ) -> Box<SourceCodeInfoFuture<Self::Error>>;
+  ) -> Box<SourceCodeInfoFuture>;
 }
 
-struct PendingLoad<E: Error> {
+struct PendingLoad {
   url: String,
   is_root: bool,
-  source_code_info_future: Box<SourceCodeInfoFuture<E>>,
+  source_code_info_future: Box<SourceCodeInfoFuture>,
 }
 
 /// This future is used to implement parallel async module loading without
@@ -71,7 +68,7 @@ pub struct RecursiveLoad<L: Loader> {
   loader: L,
   isolate: Arc<Mutex<Isolate>>,
   modules: Arc<Mutex<Modules>>,
-  pending: Vec<PendingLoad<L::Error>>,
+  pending: Vec<PendingLoad>,
   is_pending: HashSet<String>,
   phantom: PhantomData<L>,
   // TODO(ry) The following can all be combined into a single enum State type.
@@ -106,7 +103,7 @@ impl<L: Loader> RecursiveLoad<L> {
     specifier: &str,
     referrer: &str,
     parent_id: Option<deno_mod>,
-  ) -> Result<String, L::Error> {
+  ) -> Result<String, ErrBox> {
     let is_root = parent_id.is_none();
     let module_specifier = self.loader.resolve(specifier, referrer, is_root)?;
     let module_name = module_specifier.to_string();
@@ -142,22 +139,16 @@ impl<L: Loader> RecursiveLoad<L> {
   }
 }
 
-#[derive(Debug, PartialEq)]
-pub enum JSErrorOr<E> {
-  JSError(JSError),
-  Other(E),
-}
-
 impl<L: Loader> Future for RecursiveLoad<L> {
   type Item = deno_mod;
-  type Error = JSErrorOr<L::Error>;
+  type Error = ErrBox;
 
   fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
     if self.root.is_none() && self.root_specifier.is_some() {
       let s = self.root_specifier.take().unwrap();
       match self.add(&s, ".", None) {
         Err(err) => {
-          return Err(JSErrorOr::Other(err));
+          return Err(err);
         }
         Ok(root) => {
           self.root = Some(root);
@@ -172,7 +163,7 @@ impl<L: Loader> Future for RecursiveLoad<L> {
       let pending = &mut self.pending[i];
       match pending.source_code_info_future.poll() {
         Err(err) => {
-          return Err(JSErrorOr::Other(err));
+          return Err(err);
         }
         Ok(Async::NotReady) => {
           i += 1;
@@ -200,18 +191,15 @@ impl<L: Loader> Future for RecursiveLoad<L> {
           if !is_module_registered {
             let module_name = &source_code_info.module_name;
 
-            let result = {
+            let mod_id = {
               let isolate = self.isolate.lock().unwrap();
               isolate.mod_new(
                 completed.is_root,
                 module_name,
                 &source_code_info.code,
               )
-            };
+            }?;
-            if let Err(err) = result {
+
-              return Err(JSErrorOr::JSError(err));
-            }
-            let mod_id = result.unwrap();
             if completed.is_root {
               assert!(self.root_id.is_none());
               self.root_id = Some(mod_id);
@@ -235,9 +223,7 @@ impl<L: Loader> Future for RecursiveLoad<L> {
             };
             let referrer = module_name;
             for specifier in imports {
-              self
+              self.add(&specifier, referrer, Some(mod_id))?;
-                .add(&specifier, referrer, Some(mod_id))
-                .map_err(JSErrorOr::Other)?;
             }
           } else if need_alias {
             let mut modules = self.modules.lock().unwrap();
@@ -252,9 +238,8 @@ impl<L: Loader> Future for RecursiveLoad<L> {
     }
 
     let root_id = self.root_id.unwrap();
-    let result = {
+
-      let mut resolve_cb =
+    let mut resolve_cb = |specifier: &str, referrer_id: deno_mod| -> deno_mod {
-        |specifier: &str, referrer_id: deno_mod| -> deno_mod {
       let modules = self.modules.lock().unwrap();
       let referrer = modules.get_name(referrer_id).unwrap();
       // this callback is only called for non-root modules
@@ -270,13 +255,9 @@ impl<L: Loader> Future for RecursiveLoad<L> {
     };
 
     let mut isolate = self.isolate.lock().unwrap();
-      isolate.mod_instantiate(root_id, &mut resolve_cb)
+    isolate
-    };
+      .mod_instantiate(root_id, &mut resolve_cb)
-
+      .map(|_| Async::Ready(root_id))
-    match result {
-      Err(err) => Err(JSErrorOr::JSError(err)),
-      Ok(()) => Ok(Async::Ready(root_id)),
-    }
   }
 }
 
@@ -537,6 +518,7 @@ mod tests {
   use super::*;
   use crate::isolate::js_check;
   use crate::isolate::tests::*;
+  use std::error::Error;
   use std::fmt;
 
   struct MockLoader {
@@ -607,9 +589,9 @@ mod tests {
 
   impl Future for DelayedSourceCodeFuture {
     type Item = SourceCodeInfo;
-    type Error = MockError;
+    type Error = ErrBox;
 
-    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
+    fn poll(&mut self) -> Poll<Self::Item, ErrBox> {
       self.counter += 1;
       if self.url == "file:///never_ready.js"
         || (self.url == "file:///slow.js" && self.counter < 2)
@@ -621,20 +603,18 @@ mod tests {
           code: src.0.to_owned(),
           module_name: src.1.to_owned(),
         })),
-        None => Err(MockError::LoadErr),
+        None => Err(MockError::LoadErr.into()),
       }
     }
   }
 
   impl Loader for MockLoader {
-    type Error = MockError;
-
     fn resolve(
       &self,
       specifier: &str,
       referrer: &str,
       _is_root: bool,
-    ) -> Result<ModuleSpecifier, Self::Error> {
+    ) -> Result<ModuleSpecifier, ErrBox> {
       let referrer = if referrer == "." {
         "file:///"
       } else {
@@ -646,20 +626,20 @@ mod tests {
       let output_specifier =
         match ModuleSpecifier::resolve_import(specifier, referrer) {
           Ok(specifier) => specifier,
-          Err(..) => return Err(MockError::ResolveErr),
+          Err(..) => return Err(MockError::ResolveErr.into()),
         };
 
       if mock_source_code(&output_specifier.to_string()).is_some() {
         Ok(output_specifier)
       } else {
-        Err(MockError::ResolveErr)
+        Err(MockError::ResolveErr.into())
       }
     }
 
     fn load(
       &self,
       module_specifier: &ModuleSpecifier,
-    ) -> Box<SourceCodeInfoFuture<Self::Error>> {
+    ) -> Box<SourceCodeInfoFuture> {
       let mut loads = self.loads.lock().unwrap();
       loads.push(module_specifier.to_string());
       let url = module_specifier.to_string();
@@ -962,8 +942,11 @@ mod tests {
       RecursiveLoad::new("/bad_import.js", loader, isolate, modules);
     let result = recursive_load.poll();
     assert!(result.is_err());
-    let either_err = result.err().unwrap();
+    let err = result.err().unwrap();
-    assert_eq!(either_err, JSErrorOr::Other(MockError::ResolveErr));
+    assert_eq!(
+      err.downcast_ref::<MockError>().unwrap(),
+      &MockError::ResolveErr
+    );
   }
 
   #[test]