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src: simplify AliasedBuffer lifetime management

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Rely on the V8 garbage collector to take care of managing
the lifetime of the underlying memory of an `AliasedBuffer`.

PR-URL: https://github.com/nodejs/node/pull/26196
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Minwoo Jung <minwoo@nodesource.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
This commit is contained in:
Anna Henningsen
2019-02-18 22:28:17 +01:00
parent 6fb7baf935
commit d1011f6bbf
1 changed files with 15 additions and 30 deletions
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45
src/aliased_buffer.h
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@@ -30,19 +30,17 @@ class AliasedBuffer {
AliasedBuffer(v8::Isolate* isolate, const size_t count)
: isolate_(isolate),
count_(count),
byte_offset_(0),
free_buffer_(true) {
byte_offset_(0) {
CHECK_GT(count, 0);
const v8::HandleScope handle_scope(isolate_);
const size_t size_in_bytes = sizeof(NativeT) * count;
// allocate native buffer
buffer_ = Calloc<NativeT>(count);
const size_t size_in_bytes =
MultiplyWithOverflowCheck(sizeof(NativeT), count);
// allocate v8 ArrayBuffer
v8::Local<v8::ArrayBuffer> ab = v8::ArrayBuffer::New(
isolate_, buffer_, size_in_bytes);
isolate_, size_in_bytes);
buffer_ = static_cast<NativeT*>(ab->GetContents().Data());
// allocate v8 TypedArray
v8::Local<V8T> js_array = V8T::New(ab, byte_offset_, count);
@@ -65,8 +63,7 @@ class AliasedBuffer {
v8::Uint8Array>& backing_buffer)
: isolate_(isolate),
count_(count),
byte_offset_(byte_offset),
free_buffer_(false) {
byte_offset_(byte_offset) {
const v8::HandleScope handle_scope(isolate_);
v8::Local<v8::ArrayBuffer> ab = backing_buffer.GetArrayBuffer();
@@ -74,7 +71,8 @@ class AliasedBuffer {
// validate that the byte_offset is aligned with sizeof(NativeT)
CHECK_EQ(byte_offset & (sizeof(NativeT) - 1), 0);
// validate this fits inside the backing buffer
CHECK_LE(sizeof(NativeT) * count, ab->ByteLength() - byte_offset);
CHECK_LE(MultiplyWithOverflowCheck(sizeof(NativeT), count),
ab->ByteLength() - byte_offset);
buffer_ = reinterpret_cast<NativeT*>(
const_cast<uint8_t*>(backing_buffer.GetNativeBuffer() + byte_offset));
@@ -87,25 +85,16 @@ class AliasedBuffer {
: isolate_(that.isolate_),
count_(that.count_),
byte_offset_(that.byte_offset_),
buffer_(that.buffer_),
free_buffer_(false) {
buffer_(that.buffer_) {
js_array_ = v8::Global<V8T>(that.isolate_, that.GetJSArray());
}
~AliasedBuffer() {
if (free_buffer_ && buffer_ != nullptr) {
free(buffer_);
}
js_array_.Reset();
}
AliasedBuffer& operator=(AliasedBuffer&& that) noexcept {
this->~AliasedBuffer();
isolate_ = that.isolate_;
count_ = that.count_;
byte_offset_ = that.byte_offset_;
buffer_ = that.buffer_;
free_buffer_ = that.free_buffer_;
js_array_.Reset(isolate_, that.js_array_.Get(isolate_));
@@ -231,20 +220,19 @@ class AliasedBuffer {
void reserve(size_t new_capacity) {
DCHECK_GE(new_capacity, count_);
DCHECK_EQ(byte_offset_, 0);
DCHECK(free_buffer_);
const v8::HandleScope handle_scope(isolate_);
const size_t old_size_in_bytes = sizeof(NativeT) * count_;
const size_t new_size_in_bytes = sizeof(NativeT) * new_capacity;
// allocate new native buffer
NativeT* new_buffer = Calloc<NativeT>(new_capacity);
// copy old content
memcpy(new_buffer, buffer_, old_size_in_bytes);
// allocate v8 new ArrayBuffer
v8::Local<v8::ArrayBuffer> ab = v8::ArrayBuffer::New(
isolate_, new_buffer, new_size_in_bytes);
isolate_, new_size_in_bytes);
// allocate new native buffer
NativeT* new_buffer = static_cast<NativeT*>(ab->GetContents().Data());
// copy old content
memcpy(new_buffer, buffer_, old_size_in_bytes);
// allocate v8 TypedArray
v8::Local<V8T> js_array = V8T::New(ab, byte_offset_, new_capacity);
@@ -252,8 +240,6 @@ class AliasedBuffer {
// move over old v8 TypedArray
js_array_ = std::move(v8::Global<V8T>(isolate_, js_array));
// Free old buffer and set new values
free(buffer_);
buffer_ = new_buffer;
count_ = new_capacity;
}
@@ -264,7 +250,6 @@ class AliasedBuffer {
size_t byte_offset_;
NativeT* buffer_;
v8::Global<V8T> js_array_;
bool free_buffer_;
};
} // namespace node