Current File : //proc/self/root/usr/src/node-v0.10.4/src/slab_allocator.cc
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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#include "v8.h"
#include "node.h"
#include "node_buffer.h"
#include "slab_allocator.h"
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
using v8::Handle;
using v8::HandleScope;
using v8::Integer;
using v8::Local;
using v8::Null;
using v8::Object;
using v8::Persistent;
using v8::String;
using v8::Value;
using v8::V8;
namespace node {
SlabAllocator::SlabAllocator(unsigned int size) {
size_ = ROUND_UP(size ? size : 1, 8192);
initialized_ = false;
}
SlabAllocator::~SlabAllocator() {
if (!initialized_) return;
if (V8::IsDead()) return;
slab_sym_.Dispose();
slab_sym_.Clear();
slab_.Dispose();
slab_.Clear();
}
void SlabAllocator::Initialize() {
HandleScope scope;
char sym[256];
snprintf(sym, sizeof(sym), "slab_%p", this); // namespace object key
offset_ = 0;
last_ptr_ = NULL;
initialized_ = true;
slab_sym_ = Persistent<String>::New(String::New(sym));
}
static Local<Object> NewSlab(unsigned int size) {
HandleScope scope;
Local<Value> arg = Integer::NewFromUnsigned(ROUND_UP(size, 16));
Local<Object> buf = Buffer::constructor_template
->GetFunction()
->NewInstance(1, &arg);
return scope.Close(buf);
}
char* SlabAllocator::Allocate(Handle<Object> obj, unsigned int size) {
HandleScope scope;
assert(!obj.IsEmpty());
if (size == 0) return NULL;
if (!initialized_) Initialize();
if (size > size_) {
Local<Object> buf = NewSlab(size);
obj->SetHiddenValue(slab_sym_, buf);
return Buffer::Data(buf);
}
if (slab_.IsEmpty() || offset_ + size > size_) {
slab_.Dispose();
slab_.Clear();
slab_ = Persistent<Object>::New(NewSlab(size_));
offset_ = 0;
last_ptr_ = NULL;
}
obj->SetHiddenValue(slab_sym_, slab_);
last_ptr_ = Buffer::Data(slab_) + offset_;
offset_ += size;
return last_ptr_;
}
Local<Object> SlabAllocator::Shrink(Handle<Object> obj,
char* ptr,
unsigned int size) {
HandleScope scope;
Local<Value> slab_v = obj->GetHiddenValue(slab_sym_);
obj->SetHiddenValue(slab_sym_, Null());
assert(!slab_v.IsEmpty());
assert(slab_v->IsObject());
Local<Object> slab = slab_v->ToObject();
assert(ptr != NULL);
if (ptr == last_ptr_) {
last_ptr_ = NULL;
offset_ = ptr - Buffer::Data(slab) + ROUND_UP(size, 16);
}
return scope.Close(slab);
}
} // namespace node
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