The bindings/ directory

bindings/ contains code for V8-DOM bindings. bindings/ is a layer that implements high-performance C++ bindings between V8 and DOM per the Web IDL spec.

Directory structure

bindings/ consists of the following directories:

• Source/bindings/scripts/ implements the IDLCompiler.md in Python. The IDL compiler is responsible for auto-generating C++ bindings code for all Web IDL files per the Web IDL spec.

• Source/bindings/templates/ is a set of Jinja templates used by the IDL compiler.

• //out/*/gen/blink/bindings/ is a directory where the auto-generated code is generated.

• Source/bindings/tests/ is a set of tests for the IDL compiler. You can run the tests by tools/run_bindings_tests.py.

• Source/platform/bindings/, Source/bindings/core/ and Source/bindings/modules/ provide a bunch of utility classes that encapsulate the complexity of bare V8 APIs. Utility classes that purely depend on V8 APIs go to Source/platform/bindings/. Utility classes that depend on Source/core/ go to Source/bindings/core/. Utility classes that depend on Source/modules/ go to Source/bindings/modules/. Since V8 APIs are low-level and error-prone, Souce/core/ and Source/modules/ are encouraged to use the utility classes instead of directly using the bare V8 APIs. If a class in Source/core/ or Source/modules/ is using a bunch of bare V8 APIs, consider moving the class to Source/bindings/core/ and Source/bindings/modules/. The point is that we should put all the complexity around V8 APIs into Source/bindings/ so that the code ie kept under control of the binding team.

Resources

• IDLCompiler.md explains the IDL compiler.

• V8BindingDesign.md explains basic concepts of the bindings architecture; e.g., Isolate, Context, World, wrapper objects etc.

• TraceWrapperReference.md explains how the lifetime of wrapper objects is maintained by the V8 GC.

• IDLExtendedAttributes.md explains all extended IDL attributes used in Web IDL files in Blink. If you have any question about IDL files, see this document.

• IDLUnionTypes.md explains how to use IDL union types.

• v8.h defines V8 APIs with good documentation.

When you use V8 APIs, ask blink-reviews-bindings@ for review!

V8 APIs are sometimes hard to use. It's easy to use a wrong v8::Context, it's easy to leak window objects, it's easy to ignore exceptions incorrectly etc. It is not disallowed to use bare V8 APIs in Source/core/ and Source/modules/ but when you use V8 APIs, please ask blink-reviews-bindings@chromium.org for review.

Contact

If you have any question, ask blink-reviews-bindings@chromium.org.