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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef ScriptState_h
#define ScriptState_h
#include "bindings/core/v8/ScopedPersistent.h"
#include "bindings/core/v8/V8PerContextData.h"
#include "wtf/RefCounted.h"
#include "wtf/Vector.h"
#include <v8.h>
namespace blink {
class LocalDOMWindow;
class DOMWrapperWorld;
class ExecutionContext;
class LocalFrame;
class ScriptValue;
// ScriptState is created when v8::Context is created.
// ScriptState is destroyed when v8::Context is garbage-collected and
// all V8 proxy objects that have references to the ScriptState are destructed.
class ScriptState : public RefCounted<ScriptState> {
WTF_MAKE_NONCOPYABLE(ScriptState);
public:
class Scope {
public:
// You need to make sure that scriptState->context() is not empty before creating a Scope.
explicit Scope(ScriptState* scriptState)
: m_handleScope(scriptState->isolate())
, m_context(scriptState->context())
{
ASSERT(scriptState->contextIsValid());
m_context->Enter();
}
~Scope()
{
m_context->Exit();
}
private:
v8::HandleScope m_handleScope;
v8::Handle<v8::Context> m_context;
};
static PassRefPtr<ScriptState> create(v8::Handle<v8::Context>, PassRefPtr<DOMWrapperWorld>);
virtual ~ScriptState();
static ScriptState* current(v8::Isolate* isolate)
{
return from(isolate->GetCurrentContext());
}
static ScriptState* from(v8::Handle<v8::Context> context)
{
ASSERT(!context.IsEmpty());
ScriptState* scriptState = static_cast<ScriptState*>(context->GetAlignedPointerFromEmbedderData(v8ContextPerContextDataIndex));
// ScriptState::from() must not be called for a context that does not have
// valid embedder data in the embedder field.
RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(scriptState);
RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(scriptState->context() == context);
return scriptState;
}
static ScriptState* forMainWorld(LocalFrame*);
v8::Isolate* isolate() const { return m_isolate; }
DOMWrapperWorld& world() const { return *m_world; }
LocalDOMWindow* domWindow() const;
virtual ExecutionContext* executionContext() const;
virtual void setExecutionContext(ExecutionContext*);
// This can return an empty handle if the v8::Context is gone.
v8::Handle<v8::Context> context() const { return m_context.newLocal(m_isolate); }
bool contextIsValid() const { return !m_context.isEmpty() && !m_globalObjectDetached; }
void detachGlobalObject();
void clearContext() { return m_context.clear(); }
V8PerContextData* perContextData() const { return m_perContextData.get(); }
void disposePerContextData();
class Observer {
public:
virtual ~Observer() { }
virtual void willDisposeScriptState(ScriptState*) = 0;
};
void addObserver(Observer*);
void removeObserver(Observer*);
bool evalEnabled() const;
void setEvalEnabled(bool);
ScriptValue getFromGlobalObject(const char* name);
protected:
ScriptState(v8::Handle<v8::Context>, PassRefPtr<DOMWrapperWorld>);
private:
v8::Isolate* m_isolate;
// This persistent handle is weak.
ScopedPersistent<v8::Context> m_context;
// This RefPtr doesn't cause a cycle because all persistent handles that DOMWrapperWorld holds are weak.
RefPtr<DOMWrapperWorld> m_world;
// This OwnPtr causes a cycle:
// V8PerContextData --(Persistent)--> v8::Context --(RefPtr)--> ScriptState --(OwnPtr)--> V8PerContextData
// So you must explicitly clear the OwnPtr by calling disposePerContextData()
// once you no longer need V8PerContextData. Otherwise, the v8::Context will leak.
OwnPtr<V8PerContextData> m_perContextData;
bool m_globalObjectDetached;
Vector<Observer*> m_observers;
};
class ScriptStateForTesting : public ScriptState {
public:
static PassRefPtr<ScriptStateForTesting> create(v8::Handle<v8::Context>, PassRefPtr<DOMWrapperWorld>);
virtual ExecutionContext* executionContext() const override;
virtual void setExecutionContext(ExecutionContext*) override;
private:
ScriptStateForTesting(v8::Handle<v8::Context>, PassRefPtr<DOMWrapperWorld>);
ExecutionContext* m_executionContext;
};
// ScriptStateProtectingContext keeps the context associated with the ScriptState alive.
// You need to call clear() once you no longer need the context. Otherwise, the context will leak.
class ScriptStateProtectingContext {
WTF_MAKE_NONCOPYABLE(ScriptStateProtectingContext);
public:
ScriptStateProtectingContext(ScriptState* scriptState)
: m_scriptState(scriptState)
{
if (m_scriptState)
m_context.set(m_scriptState->isolate(), m_scriptState->context());
}
ScriptState* operator->() const { return m_scriptState.get(); }
ScriptState* get() const { return m_scriptState.get(); }
void clear()
{
m_scriptState = nullptr;
m_context.clear();
}
private:
RefPtr<ScriptState> m_scriptState;
ScopedPersistent<v8::Context> m_context;
};
}
#endif // ScriptState_h
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