handles.cc.svn-base

Google浏览器V8内核代码

// Copyright 2006-2008 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
//       disclaimer in the documentation and/or other materials provided
//       with the distribution.
//     * Neither the name of Google Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "v8.h"

#include "accessors.h"
#include "api.h"
#include "bootstrapper.h"
#include "compiler.h"
#include "debug.h"
#include "execution.h"
#include "global-handles.h"
#include "natives.h"
#include "runtime.h"

namespace v8 { namespace internal {

#define CALL_GC(RESULT)                                             \
  {                                                                 \
    Failure* __failure__ = Failure::cast(RESULT);                   \
    if (!Heap::CollectGarbage(__failure__->requested(),             \
                              __failure__->allocation_space())) {   \
       /* TODO(1181417): Fix this. */                               \
       V8::FatalProcessOutOfMemory("Handles");                      \
    }                                                               \
  }


Handle<FixedArray> AddKeysFromJSArray(Handle<FixedArray> content,
                                      Handle<JSArray> array) {
  CALL_HEAP_FUNCTION(content->AddKeysFromJSArray(*array), FixedArray);
}


Handle<FixedArray> UnionOfKeys(Handle<FixedArray> first,
                               Handle<FixedArray> second) {
  CALL_HEAP_FUNCTION(first->UnionOfKeys(*second), FixedArray);
}


Handle<JSGlobalObject> ReinitializeJSGlobalObject(
    Handle<JSFunction> constructor,
    Handle<JSGlobalObject> global) {
  CALL_HEAP_FUNCTION(Heap::ReinitializeJSGlobalObject(*constructor, *global),
                     JSGlobalObject);
}


void SetExpectedNofProperties(Handle<JSFunction> func, int nof) {
  func->shared()->set_expected_nof_properties(nof);
  if (func->has_initial_map()) {
    Handle<Map> new_initial_map =
        Factory::CopyMapDropTransitions(Handle<Map>(func->initial_map()));
    new_initial_map->set_unused_property_fields(nof);
    func->set_initial_map(*new_initial_map);
  }
}


void SetPrototypeProperty(Handle<JSFunction> func, Handle<JSObject> value) {
  CALL_HEAP_FUNCTION_VOID(func->SetPrototype(*value));
}


void SetExpectedNofPropertiesFromEstimate(Handle<SharedFunctionInfo> shared,
                                          int estimate) {
  // TODO(1231235): We need dynamic feedback to estimate the number
  // of expected properties in an object. The static hack below
  // is barely a solution.
  shared->set_expected_nof_properties(estimate + 2);
}


void SetExpectedNofPropertiesFromEstimate(Handle<JSFunction> func,
                                          int estimate) {
  // TODO(1231235): We need dynamic feedback to estimate the number
  // of expected properties in an object. The static hack below
  // is barely a solution.
  SetExpectedNofProperties(func, estimate + 2);
}


void NormalizeProperties(Handle<JSObject> object) {
  CALL_HEAP_FUNCTION_VOID(object->NormalizeProperties());
}


void NormalizeElements(Handle<JSObject> object) {
  CALL_HEAP_FUNCTION_VOID(object->NormalizeElements());
}


void TransformToFastProperties(Handle<JSObject> object,
                               int unused_property_fields) {
  CALL_HEAP_FUNCTION_VOID(
      object->TransformToFastProperties(unused_property_fields));
}


void FlattenString(Handle<String> string) {
  if (string->IsFlat()) return;
  CALL_HEAP_FUNCTION_VOID(String::cast(*string)->Flatten());
  ASSERT(string->IsFlat());
}


Handle<Object> SetPrototype(Handle<JSFunction> function,
                            Handle<Object> prototype) {
  CALL_HEAP_FUNCTION(Accessors::FunctionSetPrototype(*function,
                                                     *prototype,
                                                     NULL),
                     Object);
}


void AddProperty(Handle<JSObject> object,
                 Handle<String> key,
                 Handle<Object> value,
                 PropertyAttributes attributes) {
  CALL_HEAP_FUNCTION_VOID(object->AddProperty(*key, *value, attributes));
}

Handle<Object> SetProperty(Handle<JSObject> object,
                           Handle<String> key,
                           Handle<Object> value,
                           PropertyAttributes attributes) {
  CALL_HEAP_FUNCTION(object->SetProperty(*key, *value, attributes), Object);
}


Handle<Object> SetProperty(Handle<Object> object,
                           Handle<Object> key,
                           Handle<Object> value,
                           PropertyAttributes attributes) {
  CALL_HEAP_FUNCTION(Runtime::SetObjectProperty(object, key, value, attributes),
                     Object);
}


Handle<Object> SetPropertyWithInterceptor(Handle<JSObject> object,
                                          Handle<String> key,
                                          Handle<Object> value,
                                          PropertyAttributes attributes) {
  CALL_HEAP_FUNCTION(object->SetPropertyWithInterceptor(*key,
                                                        *value,
                                                        attributes),
                     Object);
}


Handle<Object> GetProperty(Handle<JSObject> obj,
                           const char* name) {
  Handle<String> str = Factory::LookupAsciiSymbol(name);
  CALL_HEAP_FUNCTION(obj->GetProperty(*str), Object);
}


Handle<Object> GetProperty(Handle<Object> obj,
                           Handle<Object> key) {
  CALL_HEAP_FUNCTION(Runtime::GetObjectProperty(obj, key), Object);
}


Handle<Object> GetPropertyWithInterceptor(Handle<JSObject> receiver,
                                          Handle<JSObject> holder,
                                          Handle<String> name,
                                          PropertyAttributes* attributes) {
  CALL_HEAP_FUNCTION(holder->GetPropertyWithInterceptor(*receiver,
                                                        *name,
                                                        attributes),
                     Object);
}


Handle<Object> GetPrototype(Handle<Object> obj) {
  Handle<Object> result(obj->GetPrototype());
  return result;
}


Handle<Object> DeleteElement(Handle<JSObject> obj,
                             uint32_t index) {
  CALL_HEAP_FUNCTION(obj->DeleteElement(index), Object);
}


Handle<Object> DeleteProperty(Handle<JSObject> obj,
                              Handle<String> prop) {
  CALL_HEAP_FUNCTION(obj->DeleteProperty(*prop), Object);
}


Handle<Object> LookupSingleCharacterStringFromCode(uint32_t index) {
  CALL_HEAP_FUNCTION(Heap::LookupSingleCharacterStringFromCode(index), Object);
}


Handle<String> SubString(Handle<String> str, int start, int end) {
  CALL_HEAP_FUNCTION(str->Slice(start, end), String);
}


Handle<Object> SetElement(Handle<JSObject> object,
                          uint32_t index,
                          Handle<Object> value) {
  CALL_HEAP_FUNCTION(object->SetElement(index, *value), Object);
}


Handle<JSObject> Copy(Handle<JSObject> obj, PretenureFlag pretenure) {
  CALL_HEAP_FUNCTION(obj->Copy(pretenure), JSObject);
}


// Wrappers for scripts are kept alive and cached in weak global
// handles referred from proxy objects held by the scripts as long as
// they are used. When they are not used anymore, the garbage
// collector will call the weak callback on the global handle
// associated with the wrapper and get rid of both the wrapper and the
// handle.
static void ClearWrapperCache(Persistent<v8::Object> handle, void*) {
  Handle<Object> cache = Utils::OpenHandle(*handle);
  JSValue* wrapper = JSValue::cast(*cache);
  Proxy* proxy = Script::cast(wrapper->value())->wrapper();
  ASSERT(proxy->proxy() == reinterpret_cast<Address>(cache.location()));
  proxy->set_proxy(0);
  GlobalHandles::Destroy(cache.location());
  Counters::script_wrappers.Decrement();
}


Handle<JSValue> GetScriptWrapper(Handle<Script> script) {
  Handle<Object> cache(reinterpret_cast<Object**>(script->wrapper()->proxy()));
  if (!cache.is_null()) {
    // Return the script wrapper directly from the cache.
    return Handle<JSValue>(JSValue::cast(*cache));
  }

  // Construct a new script wrapper.
  Counters::script_wrappers.Increment();
  Handle<JSFunction> constructor = Top::script_function();
  Handle<JSValue> result =
      Handle<JSValue>::cast(Factory::NewJSObject(constructor));
  result->set_value(*script);

  // Create a new weak global handle and use it to cache the wrapper
  // for future use. The cache will automatically be cleared by the
  // garbage collector when it is not used anymore.
  Handle<Object> handle = GlobalHandles::Create(*result);
  GlobalHandles::MakeWeak(handle.location(), NULL, &ClearWrapperCache);
  script->wrapper()->set_proxy(reinterpret_cast<Address>(handle.location()));
  return result;
}