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denoland-deno/core/lib.rs
Luca Casonato 3b6b75bb46
feat(core): improve resource read & write traits (#16115)
This commit introduces two new buffer wrapper types to `deno_core`. The
main benefit of these new wrappers is that they can wrap a number of
different underlying buffer types. This allows for a more flexible read
and write API on resources that will require less copying of data
between different buffer representations.

- `BufView` is a read-only view onto a buffer. It can be backed by
`ZeroCopyBuf`, `Vec<u8>`, and `bytes::Bytes`.
- `BufViewMut` is a read-write view onto a buffer. It can be cheaply
converted into a `BufView`. It can be backed by `ZeroCopyBuf` or
`Vec<u8>`.

Both new buffer views have a cursor. This means that the start point of
the view can be constrained to write / read from just a slice of the
view. Only the start point of the slice can be adjusted. The end point
is fixed. To adjust the end point, the underlying buffer needs to be
truncated.

Readable resources have been changed to better cater to resources that
do not support BYOB reads. The basic `read` method now returns a
`BufView` instead of taking a `ZeroCopyBuf` to fill. This allows the
operation to return buffers that the resource has already allocated,
instead of forcing the caller to allocate the buffer. BYOB reads are
still very useful for resources that support them, so a new `read_byob`
method has been added that takes a `BufViewMut` to fill. `op_read`
attempts to use `read_byob` if the resource supports it, which falls
back to `read` and performs an additional copy if it does not. For
Rust->JS reads this change should have no impact, but for Rust->Rust
reads, this allows the caller to avoid an additional copy in many
scenarios. This combined with the support for `BufView` to be backed by
`bytes::Bytes` allows us to avoid one data copy when piping from a
`fetch` response into an `ext/http` response.

Writable resources have been changed to take a `BufView` instead of a
`ZeroCopyBuf` as an argument. This allows for less copying of data in
certain scenarios, as described above. Additionally a new
`Resource::write_all` method has been added that takes a `BufView` and
continually attempts to write the resource until the entire buffer has
been written. Certain resources like files can override this method to
provide a more efficient `write_all` implementation.
2022-10-09 14:49:25 +00:00

153 lines
4.5 KiB
Rust

// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
mod async_cancel;
mod async_cell;
mod bindings;
pub mod error;
mod error_codes;
mod extensions;
mod flags;
mod gotham_state;
mod inspector;
mod io;
mod module_specifier;
mod modules;
mod normalize_path;
mod ops;
mod ops_builtin;
mod ops_builtin_v8;
mod ops_metrics;
mod resources;
mod runtime;
mod source_map;
// Re-exports
pub use anyhow;
pub use futures;
pub use parking_lot;
pub use serde;
pub use serde_json;
pub use serde_v8;
pub use serde_v8::ByteString;
pub use serde_v8::DetachedBuffer;
pub use serde_v8::StringOrBuffer;
pub use serde_v8::U16String;
pub use serde_v8::ZeroCopyBuf;
pub use sourcemap;
pub use url;
pub use v8;
pub use crate::async_cancel::CancelFuture;
pub use crate::async_cancel::CancelHandle;
pub use crate::async_cancel::CancelTryFuture;
pub use crate::async_cancel::Cancelable;
pub use crate::async_cancel::Canceled;
pub use crate::async_cancel::TryCancelable;
pub use crate::async_cell::AsyncMut;
pub use crate::async_cell::AsyncMutFuture;
pub use crate::async_cell::AsyncRef;
pub use crate::async_cell::AsyncRefCell;
pub use crate::async_cell::AsyncRefFuture;
pub use crate::async_cell::RcLike;
pub use crate::async_cell::RcRef;
pub use crate::extensions::Extension;
pub use crate::extensions::ExtensionBuilder;
pub use crate::extensions::OpDecl;
pub use crate::extensions::OpMiddlewareFn;
pub use crate::flags::v8_set_flags;
pub use crate::inspector::InspectorMsg;
pub use crate::inspector::InspectorMsgKind;
pub use crate::inspector::InspectorSessionProxy;
pub use crate::inspector::JsRuntimeInspector;
pub use crate::inspector::LocalInspectorSession;
pub use crate::io::BufMutView;
pub use crate::io::BufView;
pub use crate::io::WriteOutcome;
pub use crate::module_specifier::resolve_import;
pub use crate::module_specifier::resolve_path;
pub use crate::module_specifier::resolve_url;
pub use crate::module_specifier::resolve_url_or_path;
pub use crate::module_specifier::ModuleResolutionError;
pub use crate::module_specifier::ModuleSpecifier;
pub use crate::module_specifier::DUMMY_SPECIFIER;
pub use crate::modules::FsModuleLoader;
pub use crate::modules::ModuleId;
pub use crate::modules::ModuleLoader;
pub use crate::modules::ModuleSource;
pub use crate::modules::ModuleSourceFuture;
pub use crate::modules::ModuleType;
pub use crate::modules::NoopModuleLoader;
pub use crate::normalize_path::normalize_path;
pub use crate::ops::Op;
pub use crate::ops::OpAsyncFuture;
pub use crate::ops::OpCall;
pub use crate::ops::OpError;
pub use crate::ops::OpFn;
pub use crate::ops::OpId;
pub use crate::ops::OpResult;
pub use crate::ops::OpState;
pub use crate::ops::PromiseId;
pub use crate::ops_builtin::op_close;
pub use crate::ops_builtin::op_print;
pub use crate::ops_builtin::op_resources;
pub use crate::ops_builtin::op_void_async;
pub use crate::ops_builtin::op_void_sync;
pub use crate::ops_metrics::OpsTracker;
pub use crate::resources::AsyncResult;
pub use crate::resources::Resource;
pub use crate::resources::ResourceId;
pub use crate::resources::ResourceTable;
pub use crate::runtime::CompiledWasmModuleStore;
pub use crate::runtime::CrossIsolateStore;
pub use crate::runtime::GetErrorClassFn;
pub use crate::runtime::JsErrorCreateFn;
pub use crate::runtime::JsRealm;
pub use crate::runtime::JsRuntime;
pub use crate::runtime::RuntimeOptions;
pub use crate::runtime::SharedArrayBufferStore;
pub use crate::runtime::Snapshot;
pub use crate::runtime::V8_WRAPPER_OBJECT_INDEX;
pub use crate::runtime::V8_WRAPPER_TYPE_INDEX;
pub use crate::source_map::SourceMapGetter;
pub use deno_ops::op;
pub fn v8_version() -> &'static str {
v8::V8::get_version()
}
/// An internal module re-exporting funcs used by the #[op] (`deno_ops`) macro
#[doc(hidden)]
pub mod _ops {
pub use super::bindings::throw_type_error;
pub use super::error_codes::get_error_code;
pub use super::ops::to_op_result;
pub use super::ops::OpCtx;
pub use super::runtime::queue_async_op;
pub use super::runtime::V8_WRAPPER_OBJECT_INDEX;
pub use super::runtime::V8_WRAPPER_TYPE_INDEX;
}
/// A helper macro that will return a call site in Rust code. Should be
/// used when executing internal one-line scripts for JsRuntime lifecycle.
///
/// Returns a string in form of: "`[deno:<filename>:<line>:<column>]`"
#[macro_export]
macro_rules! located_script_name {
() => {
format!(
"[deno:{}:{}:{}]",
std::file!(),
std::line!(),
std::column!()
);
};
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_v8_version() {
assert!(v8_version().len() > 3);
}
}