gecko/tools/profiler/NSPRInterposer.cpp

140 lines
4.4 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/. */
#include "NSPRInterposer.h"
#include "private/pprio.h"
using namespace mozilla;
StaticAutoPtr<NSPRInterposer> NSPRInterposer::sSingleton;
const char* NSPRAutoTimer::sModuleInfo = "NSPR";
/* static */ IOInterposerModule*
NSPRInterposer::GetInstance(IOInterposeObserver* aObserver,
IOInterposeObserver::Operation aOpsToInterpose)
{
// We can't actually use this assertion because we initialize this code
// before XPCOM is initialized, so NS_IsMainThread() always returns false.
// MOZ_ASSERT(NS_IsMainThread());
if (!sSingleton) {
nsAutoPtr<NSPRInterposer> newObj(new NSPRInterposer());
if (!newObj->Init(aObserver, aOpsToInterpose)) {
return nullptr;
}
sSingleton = newObj.forget();
}
return sSingleton;
}
/* static */ void
NSPRInterposer::ClearInstance()
{
// We can't actually use this assertion because we execute this code
// after XPCOM is shut down, so NS_IsMainThread() always returns false.
// MOZ_ASSERT(NS_IsMainThread());
sSingleton = nullptr;
}
NSPRInterposer::NSPRInterposer()
:mObserver(nullptr),
mFileIOMethods(nullptr),
mEnabled(false),
mOrigReadFn(nullptr),
mOrigWriteFn(nullptr),
mOrigFSyncFn(nullptr)
{
}
NSPRInterposer::~NSPRInterposer()
{
// We can't actually use this assertion because we execute this code
// after XPCOM is shut down, so NS_IsMainThread() always returns false.
// MOZ_ASSERT(NS_IsMainThread());
Enable(false);
mFileIOMethods->read = mOrigReadFn;
mFileIOMethods->write = mOrigWriteFn;
mFileIOMethods->fsync = mOrigFSyncFn;
sSingleton = nullptr;
}
bool
NSPRInterposer::Init(IOInterposeObserver* aObserver,
IOInterposeObserver::Operation aOpsToInterpose)
{
// We can't actually use this assertion because we initialize this code
// before XPCOM is initialized, so NS_IsMainThread() always returns false.
// MOZ_ASSERT(NS_IsMainThread());
if (!aObserver || !(aOpsToInterpose & IOInterposeObserver::OpAll)) {
return false;
}
mObserver = aObserver;
// Yes, this is not very kosher; now show me an example of function
// interposing an unsuspecting target that /is/.
mFileIOMethods = const_cast<PRIOMethods*>(PR_GetFileMethods());
if (!mFileIOMethods) {
return false;
}
mOrigReadFn = mFileIOMethods->read;
mOrigWriteFn = mFileIOMethods->write;
mOrigFSyncFn = mFileIOMethods->fsync;
if (!mOrigReadFn || !mOrigWriteFn || !mOrigFSyncFn) {
return false;
}
if (aOpsToInterpose & IOInterposeObserver::OpRead) {
mFileIOMethods->read = &NSPRInterposer::Read;
}
if (aOpsToInterpose & IOInterposeObserver::OpWrite) {
mFileIOMethods->write = &NSPRInterposer::Write;
}
if (aOpsToInterpose & IOInterposeObserver::OpFSync) {
mFileIOMethods->fsync = &NSPRInterposer::FSync;
}
return true;
}
void
NSPRInterposer::Enable(bool aEnable)
{
mEnabled = aEnable ? 1 : 0;
}
int32_t PR_CALLBACK
NSPRInterposer::Read(PRFileDesc* aFd, void* aBuf, int32_t aAmt)
{
// If we don't have valid pointers, something is very wrong.
NS_ASSERTION(sSingleton, "NSPRInterposer::sSingleton not available!");
NS_ASSERTION(sSingleton->mOrigReadFn, "mOrigReadFn not available!");
NS_ASSERTION(sSingleton->mObserver, "NSPRInterposer not initialized!");
NSPRAutoTimer timer(IOInterposeObserver::OpRead);
return sSingleton->mOrigReadFn(aFd, aBuf, aAmt);
}
int32_t PR_CALLBACK
NSPRInterposer::Write(PRFileDesc* aFd, const void* aBuf, int32_t aAmt)
{
// If we don't have valid pointers, something is very wrong.
NS_ASSERTION(sSingleton, "NSPRInterposer::sSingleton not available!");
NS_ASSERTION(sSingleton->mOrigWriteFn, "mOrigWriteFn not available!");
NS_ASSERTION(sSingleton->mObserver, "NSPRInterposer not initialized!");
NSPRAutoTimer timer(IOInterposeObserver::OpWrite);
return sSingleton->mOrigWriteFn(aFd, aBuf, aAmt);
}
PRStatus PR_CALLBACK
NSPRInterposer::FSync(PRFileDesc* aFd)
{
// If we don't have valid pointers, something is very wrong.
NS_ASSERTION(sSingleton, "NSPRInterposer::sSingleton not available!");
NS_ASSERTION(sSingleton->mOrigFSyncFn, "mOrigFSyncFn not available!");
NS_ASSERTION(sSingleton->mObserver, "NSPRInterposer not initialized!");
NSPRAutoTimer timer(IOInterposeObserver::OpFSync);
return sSingleton->mOrigFSyncFn(aFd);
}