MemoryPressureHandler.h [plain text]
#ifndef MemoryPressureHandler_h
#define MemoryPressureHandler_h
#include <time.h>
#include <wtf/FastAllocBase.h>
#if PLATFORM(IOS)
#include <wtf/ThreadingPrimitives.h>
#endif
namespace WebCore {
#if PLATFORM(IOS)
enum MemoryPressureReason
{
MemoryPressureReasonNone = 0,
MemoryPressureReasonVMPressure = 0x1,
MemoryPressureReasonVMStatus = 0x2
};
#endif
typedef void (*LowMemoryHandler)(bool critical);
class MemoryPressureHandler {
WTF_MAKE_FAST_ALLOCATED;
public:
friend MemoryPressureHandler& memoryPressureHandler();
void install();
void setLowMemoryHandler(LowMemoryHandler handler)
{
ASSERT(!m_installed);
m_lowMemoryHandler = handler;
}
private:
void uninstall();
void holdOff(unsigned);
MemoryPressureHandler();
~MemoryPressureHandler();
void respondToMemoryPressure();
static void releaseMemory(bool critical);
bool m_installed;
time_t m_lastRespondTime;
LowMemoryHandler m_lowMemoryHandler;
#if PLATFORM(IOS)
public:
void installMemoryReleaseBlock(void (^releaseMemoryBlock)(), bool clearPressureOnMemoryRelease = true);
void setReceivedMemoryPressure(MemoryPressureReason reason);
bool hasReceivedMemoryPressure();
void clearMemoryPressure();
bool shouldWaitForMemoryClearMessage();
void respondToMemoryPressureIfNeeded();
private:
uint32_t m_receivedMemoryPressure;
uint32_t m_memoryPressureReason;
bool m_clearPressureOnMemoryRelease;
void (^m_releaseMemoryBlock)();
CFRunLoopObserverRef m_observer;
Mutex m_observerMutex;
#endif
};
MemoryPressureHandler& memoryPressureHandler();
}
#endif // MemoryPressureHandler_h