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Anna Henningsen
b0404047c1
Logic is added to the `MessagePort` mechanism that attaches hidden objects to those instances when they are transferred that track their lifetime and maintain a reference count, to make sure that memory is freed at the appropriate times. Thanks to Stephen Belanger for reviewing this change in its original PR. Refs: https://github.com/ayojs/ayo/pull/106 PR-URL: https://github.com/nodejs/node/pull/20876 Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com> Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com> Reviewed-By: Shingo Inoue <leko.noor@gmail.com> Reviewed-By: Matteo Collina <matteo.collina@gmail.com> Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com> Reviewed-By: John-David Dalton <john.david.dalton@gmail.com> Reviewed-By: Gus Caplan <me@gus.host>
68 lines
2.3 KiB
C++
68 lines
2.3 KiB
C++
#ifndef SRC_SHAREDARRAYBUFFER_METADATA_H_
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#define SRC_SHAREDARRAYBUFFER_METADATA_H_
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#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
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#include "node.h"
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#include <memory>
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namespace node {
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namespace worker {
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class SharedArrayBufferMetadata;
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// This is an object associated with a SharedArrayBuffer, which keeps track
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// of a cross-thread reference count. Once a SharedArrayBuffer is transferred
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// for the first time (or is attempted to be transferred), one of these objects
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// is created, and the SharedArrayBuffer is moved from internalized mode into
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// externalized mode (i.e. the JS engine no longer frees the memory on its own).
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//
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// This will always be referred to using a std::shared_ptr, since it keeps
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// a reference count and is guaranteed to be thread-safe.
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typedef std::shared_ptr<SharedArrayBufferMetadata>
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SharedArrayBufferMetadataReference;
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class SharedArrayBufferMetadata
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: public std::enable_shared_from_this<SharedArrayBufferMetadata> {
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public:
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static SharedArrayBufferMetadataReference ForSharedArrayBuffer(
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Environment* env,
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v8::Local<v8::Context> context,
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v8::Local<v8::SharedArrayBuffer> source);
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~SharedArrayBufferMetadata();
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// Create a SharedArrayBuffer object for a specific Environment and Context.
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// The created SharedArrayBuffer will be in externalized mode and has
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// a hidden object attached to it, during whose lifetime the reference
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// count is increased by 1.
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v8::MaybeLocal<v8::SharedArrayBuffer> GetSharedArrayBuffer(
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Environment* env, v8::Local<v8::Context> context);
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SharedArrayBufferMetadata(SharedArrayBufferMetadata&& other) = delete;
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SharedArrayBufferMetadata& operator=(
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SharedArrayBufferMetadata&& other) = delete;
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SharedArrayBufferMetadata& operator=(
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const SharedArrayBufferMetadata&) = delete;
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SharedArrayBufferMetadata(const SharedArrayBufferMetadata&) = delete;
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private:
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explicit SharedArrayBufferMetadata(void* data, size_t size);
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// Attach a lifetime tracker object with a reference count to `target`.
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v8::Maybe<bool> AssignToSharedArrayBuffer(
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Environment* env,
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v8::Local<v8::Context> context,
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v8::Local<v8::SharedArrayBuffer> target);
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void* data = nullptr;
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size_t size = 0;
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};
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} // namespace worker
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} // namespace node
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#endif // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
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#endif // SRC_SHAREDARRAYBUFFER_METADATA_H_
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