cecb08f0c8For http2 (and eventually QUIC) we have a struct that is backed
by a v8::BackingStore and exposed to the JavaScript side as an
ArrayBuffer and TypedArray. This is similar to AliasedBuffer
except that it is fronted by a struct on the C++ side.
```c++
struct foo {
uint32_t ex1;
uint32_t ex2;
};
AliasedStruct<foo> foo_;
foo_->ex1 = 1;
foo_->ex2 = 2;
foo_.GetArrayBuffer();
```
Signed-off-by: James M Snell <jasnell@gmail.com>
PR-URL: https://github.com/nodejs/node/pull/32778
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Gerhard Stöbich <deb2001-github@yahoo.de>
63 lines
1.4 KiB
C++
63 lines
1.4 KiB
C++
#ifndef SRC_ALIASED_STRUCT_H_
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#define SRC_ALIASED_STRUCT_H_
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#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
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#include "node_internals.h"
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#include "v8.h"
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#include <memory>
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namespace node {
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// AliasedStruct is a utility that allows uses a V8 Backing Store
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// to be exposed to the C++/C side as a struct and to the
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// JavaScript side as an ArrayBuffer to efficiently share
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// data without marshalling. It is similar in nature to
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// AliasedBuffer.
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//
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// struct Foo { int x; }
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//
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// AliasedStruct<Foo> foo;
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// foo->x = 1;
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//
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// Local<ArrayBuffer> ab = foo.GetArrayBuffer();
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template <typename T>
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class AliasedStruct final {
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public:
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template <typename... Args>
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explicit AliasedStruct(v8::Isolate* isolate, Args&&... args);
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inline AliasedStruct(const AliasedStruct& that);
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inline ~AliasedStruct();
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inline AliasedStruct& operator=(AliasedStruct&& that) noexcept;
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v8::Local<v8::ArrayBuffer> GetArrayBuffer() const {
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return buffer_.Get(isolate_);
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}
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const T* Data() const { return ptr_; }
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T* Data() { return ptr_; }
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const T& operator*() const { return *ptr_; }
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T& operator*() { return *ptr_; }
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const T* operator->() const { return ptr_; }
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T* operator->() { return ptr_; }
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private:
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v8::Isolate* isolate_;
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std::shared_ptr<v8::BackingStore> store_;
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T* ptr_;
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v8::Global<v8::ArrayBuffer> buffer_;
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};
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} // namespace node
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#endif // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
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#endif // SRC_ALIASED_STRUCT_H_
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