SQLCallbackWrapper.h [plain text]
#ifndef SQLCallbackWrapper_h
#define SQLCallbackWrapper_h
#if ENABLE(SQL_DATABASE)
#include "ScriptExecutionContext.h"
#include <wtf/ThreadingPrimitives.h>
namespace WebCore {
template<typename T> class SQLCallbackWrapper {
public:
SQLCallbackWrapper(PassRefPtr<T> callback, ScriptExecutionContext* scriptExecutionContext)
: m_callback(callback)
, m_scriptExecutionContext(m_callback ? scriptExecutionContext : 0)
{
ASSERT(!m_callback || (m_scriptExecutionContext.get() && m_scriptExecutionContext->isContextThread()));
}
~SQLCallbackWrapper()
{
clear();
}
void clear()
{
ScriptExecutionContext* context;
T* callback;
{
MutexLocker locker(m_mutex);
if (!m_callback) {
ASSERT(!m_scriptExecutionContext);
return;
}
if (m_scriptExecutionContext->isContextThread()) {
m_callback = 0;
m_scriptExecutionContext = 0;
return;
}
context = m_scriptExecutionContext.release().leakRef();
callback = m_callback.release().leakRef();
}
context->postTask(SafeReleaseTask::create(callback));
}
PassRefPtr<T> unwrap()
{
MutexLocker locker(m_mutex);
ASSERT(!m_callback || m_scriptExecutionContext->isContextThread());
m_scriptExecutionContext = 0;
return m_callback.release();
}
bool hasCallback() const { return m_callback; }
private:
class SafeReleaseTask : public ScriptExecutionContext::Task {
public:
static PassOwnPtr<SafeReleaseTask> create(T* callbackToRelease)
{
return adoptPtr(new SafeReleaseTask(callbackToRelease));
}
virtual void performTask(ScriptExecutionContext* context)
{
ASSERT(m_callbackToRelease && context && context->isContextThread());
m_callbackToRelease->deref();
context->deref();
}
virtual bool isCleanupTask() const { return true; }
private:
SafeReleaseTask(T* callbackToRelease)
: m_callbackToRelease(callbackToRelease)
{
}
T* m_callbackToRelease;
};
Mutex m_mutex;
RefPtr<T> m_callback;
RefPtr<ScriptExecutionContext> m_scriptExecutionContext;
};
}
#endif // ENABLE(SQL_DATABASE)
#endif // SQLCallbackWrapper_h