/*
* Copyright (C) 2011 Google Inc. 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.
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* 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
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef V8RecursionScope_h
#define V8RecursionScope_h
#include "bindings/v8/V8PerIsolateData.h"
#include "core/dom/ExecutionContext.h"
#include "wtf/Noncopyable.h"
namespace WebCore {
// C++ calls into script contexts which are "owned" by WebKit (created in a
// process where WebKit.cpp initializes v8) must declare their type:
//
// 1. Calls into page/author script from a frame
// 2. Calls into page/author script from a worker
// 3. Calls into internal script (typically setup/teardown work)
//
// Debug-time checking of this is enforced via this class.
//
// Calls of type (1) should generally go through ScriptController, as inspector
// instrumentation is needed. ScriptController allocates V8RecursionScope for you.
// Calls of type (2) should always stack-allocate a V8RecursionScope in the same
// block as the call into script. Calls of type (3) should stack allocate a
// V8RecursionScope::MicrotaskSuppression -- this skips work that is spec'd to
// happen at the end of the outer-most script stack frame of calls into page script:
//
// http://www.whatwg.org/specs/web-apps/current-work/#perform-a-microtask-checkpoint
class V8RecursionScope {
WTF_MAKE_NONCOPYABLE(V8RecursionScope);
public:
V8RecursionScope(v8::Isolate* isolate, ExecutionContext* context)
: m_isolate(isolate)
, m_isDocumentContext(context && context->isDocument())
{
V8PerIsolateData::from(m_isolate)->incrementRecursionLevel();
}
~V8RecursionScope()
{
if (!V8PerIsolateData::from(m_isolate)->decrementRecursionLevel())
didLeaveScriptContext();
}
static int recursionLevel(v8::Isolate* isolate)
{
return V8PerIsolateData::from(isolate)->recursionLevel();
}
#ifndef NDEBUG
static bool properlyUsed(v8::Isolate* isolate)
{
return recursionLevel(isolate) > 0 || V8PerIsolateData::from(isolate)->internalScriptRecursionLevel() > 0;
}
#endif
class MicrotaskSuppression {
public:
MicrotaskSuppression(v8::Isolate* isolate)
#ifndef NDEBUG
: m_isolate(isolate)
#endif
{
#ifndef NDEBUG
V8PerIsolateData::from(m_isolate)->incrementInternalScriptRecursionLevel();
#endif
}
~MicrotaskSuppression()
{
#ifndef NDEBUG
V8PerIsolateData::from(m_isolate)->decrementInternalScriptRecursionLevel();
#endif
}
private:
#ifndef NDEBUG
v8::Isolate* m_isolate;
#endif
};
private:
void didLeaveScriptContext();
v8::Isolate* m_isolate;
bool m_isDocumentContext;
};
} // namespace WebCore
#endif // V8RecursionScope_h