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1f1a373df0
Store the full information we have on a given `SharedArrayBuffer`, and use the deleter provided by the JS engine to free the memory when that is needed. This fixes memory lifetime management for WASM buffers that are passed through a `MessageChannel` (e.g. between threads). PR-URL: https://github.com/nodejs/node/pull/25307 Reviewed-By: Gus Caplan <me@gus.host> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
67 lines
2.4 KiB
C++
67 lines
2.4 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(const v8::SharedArrayBuffer::Contents&);
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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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v8::SharedArrayBuffer::Contents contents_;
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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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