fix: put fslock around entire build process (#1525)

build.rs

@@ -96,6 +96,11 @@ fn main() {
     false
   };
 
+  // Cargo likes to run multiple build scripts at once sometimes.
+  // Nothing that follows is safe to run multiple times at once,
+  // because we store everything in a parent directory of OUT_DIR.
+  let _lockfile = acquire_lock();
+
   // Build from source
   if env_bool("V8_FROM_SOURCE") {
     if is_asan && std::env::var_os("OPT_LEVEL").unwrap_or_default() == "0" {
@@ -113,8 +118,10 @@ fn main() {
 
   print_prebuilt_src_binding_path();
 
-  // utilize a lockfile to prevent linking of
-  // only partially downloaded static library.
+  download_static_lib_binaries();
+}
+
+fn acquire_lock() -> LockFile {
   let root = env::current_dir().unwrap();
   let out_dir = env::var_os("OUT_DIR").unwrap();
   let lockfilepath = root
@@ -123,13 +130,12 @@ fn main() {
     .unwrap()
     .parent()
     .unwrap()
-    .join("lib_download.fslock");
-  println!("download lockfile: {:?}", &lockfilepath);
+    .join("v8.fslock");
   let mut lockfile = LockFile::open(&lockfilepath)
     .expect("Couldn't open lib download lockfile.");
-  lockfile.lock().expect("Couldn't get lock");
-  download_static_lib_binaries();
-  lockfile.unlock().expect("Couldn't unlock lockfile");
+  lockfile.lock_with_pid().expect("Couldn't get lock");
+  println!("lockfile: {:?}", &lockfilepath);
+  lockfile
 }
 
 fn build_binding() {

src/data.rs

@@ -158,10 +158,12 @@ macro_rules! impl_try_from {
         // Not dead: `cast()` is sometimes used in the $check expression.
         #[allow(dead_code)]
         fn cast<T>(l: Local<$source>) -> Local<T> {
-          unsafe { transmute(l) }
+          unsafe { transmute::<Local<$source>, Local<T>>(l) }
         }
         match l {
-          $value if $check => Ok(unsafe { transmute(l) }),
+          $value if $check => Ok(unsafe {
+            transmute::<Local<'s, $source>, Local<'s, $target>>(l)
+          }),
           _ => Err(DataError::bad_type::<$target, $source>())
         }
       }

src/string.rs

@@ -425,8 +425,8 @@ impl String {
         self,
         scope,
         buffer.as_mut_ptr(),
-        start.try_into().unwrap_or(int::max_value()),
-        buffer.len().try_into().unwrap_or(int::max_value()),
+        start.try_into().unwrap_or(int::MAX),
+        buffer.len().try_into().unwrap_or(int::MAX),
         options,
       ) as usize
     }
@@ -447,8 +447,8 @@ impl String {
         self,
         scope,
         buffer.as_mut_ptr(),
-        start.try_into().unwrap_or(int::max_value()),
-        buffer.len().try_into().unwrap_or(int::max_value()),
+        start.try_into().unwrap_or(int::MAX),
+        buffer.len().try_into().unwrap_or(int::MAX),
         options,
       ) as usize
     }
@@ -469,8 +469,8 @@ impl String {
         self,
         scope,
         buffer.as_mut_ptr() as *mut u8,
-        start.try_into().unwrap_or(int::max_value()),
-        buffer.len().try_into().unwrap_or(int::max_value()),
+        start.try_into().unwrap_or(int::MAX),
+        buffer.len().try_into().unwrap_or(int::MAX),
         options,
       ) as usize
     }
@@ -513,7 +513,7 @@ impl String {
         self,
         scope,
         buffer.as_mut_ptr() as *mut char,
-        buffer.len().try_into().unwrap_or(int::max_value()),
+        buffer.len().try_into().unwrap_or(int::MAX),
         &mut nchars_ref_int,
         options,
       )

src/support.rs

@@ -501,6 +501,7 @@ impl From<Option<bool>> for MaybeBool {
 #[repr(transparent)]
 pub struct CxxVTable(pub *const Opaque);
 
+#[allow(unused)]
 #[derive(Copy, Clone, Debug)]
 pub struct RustVTable<DynT>(pub *const Opaque, pub PhantomData<DynT>);