gecko/tools/profiler/NSPRInterposer.h

101 lines
2.8 KiB
C++

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef NSPRINTERPOSER_H_
#define NSPRINTERPOSER_H_
#ifdef MOZ_ENABLE_PROFILER_SPS
#include "IOInterposer.h"
#include "mozilla/Atomics.h"
#include "mozilla/TimeStamp.h"
#include "prio.h"
namespace mozilla {
/**
* This class provides main thread I/O interposing for NSPR file reads, writes,
* and fsyncs. Most methods must be called from the main thread, except for:
* Enable
* Read
* Write
* FSync
*/
class NSPRInterposer MOZ_FINAL : public IOInterposerModule
{
public:
static IOInterposerModule* GetInstance(IOInterposeObserver* aObserver,
IOInterposeObserver::Operation aOpsToInterpose);
/**
* This function must be called from the main thread, and furthermore
* it must be called when no other threads are executing in Read, Write,
* or FSync. Effectivly this restricts us to calling it only after all other
* threads have been stopped during shutdown.
*/
static void ClearInstance();
~NSPRInterposer();
void Enable(bool aEnable);
private:
NSPRInterposer();
bool Init(IOInterposeObserver* aObserver,
IOInterposeObserver::Operation aOpsToInterpose);
static PRInt32 PR_CALLBACK Read(PRFileDesc* aFd, void* aBuf, PRInt32 aAmt);
static PRInt32 PR_CALLBACK Write(PRFileDesc* aFd, const void* aBuf,
PRInt32 aAmt);
static PRStatus PR_CALLBACK FSync(PRFileDesc* aFd);
static StaticAutoPtr<NSPRInterposer> sSingleton;
friend class NSPRAutoTimer;
IOInterposeObserver* mObserver;
PRIOMethods* mFileIOMethods;
Atomic<uint32_t,ReleaseAcquire> mEnabled;
PRReadFN mOrigReadFn;
PRWriteFN mOrigWriteFn;
PRFsyncFN mOrigFSyncFn;
};
/**
* RAII class for timing the duration of an NSPR I/O call and reporting the
* result to the IOInterposeObserver.
*/
class NSPRAutoTimer
{
public:
NSPRAutoTimer(IOInterposeObserver::Operation aOp)
:mOp(aOp),
mShouldObserve(NSPRInterposer::sSingleton->mEnabled && NS_IsMainThread())
{
if (mShouldObserve) {
mStart = mozilla::TimeStamp::Now();
}
}
~NSPRAutoTimer()
{
if (mShouldObserve) {
double duration = (mozilla::TimeStamp::Now() - mStart).ToMilliseconds();
NSPRInterposer::sSingleton->mObserver->Observe(mOp, duration,
sModuleInfo);
}
}
private:
IOInterposeObserver::Operation mOp;
bool mShouldObserve;
mozilla::TimeStamp mStart;
static const char* sModuleInfo;
};
} // namespace mozilla
#endif // MOZ_ENABLE_PROFILER_SPS
#endif // NSPRINTERPOSER_H_