gecko-dev/xpcom/build/PoisonIOInterposer.h
Gerald Squelart f3b8c9b60a Bug 1529610 - LRU cache of Windows filenames in WinIOAutoObservation - r=canaltinova,florian
Caching filenames in 32-entry LRU array covers >95% of calls, and makes the average `Filename()` call 5 to 10 times cheaper.

browser_start_content_mainthreadio.js needed to be updated to handle operations that now have a filename thanks to the cache.

Since `ClearPoisonIOInterposer()` is never called (see bug 1647107), during Firefox shutdown we put LRUCache in a shutdown mode, which bypasses the cache in case it is still used at that time.

Differential Revision: https://phabricator.services.mozilla.com/D79767
2020-07-06 23:42:38 +00:00

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 mozilla_PoisonIOInterposer_h
#define mozilla_PoisonIOInterposer_h
#include "mozilla/Types.h"
#include <stdio.h>
MOZ_BEGIN_EXTERN_C
/** Register file handle to be ignored by poisoning IO interposer. This function
* and the corresponding UnRegister function are necessary for exchange of
* handles between binaries not using the same CRT on Windows (which happens
* when one of them links the static CRT). In such cases, giving file
* descriptors or FILEs
* doesn't work because _get_osfhandle fails with "invalid parameter". */
void MozillaRegisterDebugHandle(intptr_t aHandle);
/** Register file descriptor to be ignored by poisoning IO interposer */
void MozillaRegisterDebugFD(int aFd);
/** Register file to be ignored by poisoning IO interposer */
void MozillaRegisterDebugFILE(FILE* aFile);
/** Unregister file handle from being ignored by poisoning IO interposer */
void MozillaUnRegisterDebugHandle(intptr_t aHandle);
/** Unregister file descriptor from being ignored by poisoning IO interposer */
void MozillaUnRegisterDebugFD(int aFd);
/** Unregister file from being ignored by poisoning IO interposer */
void MozillaUnRegisterDebugFILE(FILE* aFile);
MOZ_END_EXTERN_C
#if defined(XP_MACOSX) || defined(XP_WIN)
# ifdef __cplusplus
namespace mozilla {
/**
* Check if a file is registered as a debug file.
*/
bool IsDebugFile(intptr_t aFileID);
/**
* Initialize IO poisoning, this is only safe to do on the main-thread when no
* other threads are running.
*
* Please, note that this probably has performance implications as all
*/
void InitPoisonIOInterposer();
# ifdef XP_MACOSX
/**
* Check that writes are dirty before reporting I/O (Mac OS X only)
* This is necessary for late-write checks on Mac OS X, but reading the buffer
* from file to see if we're writing dirty bits is expensive, so we don't want
* to do this for everything else that uses
*/
void OnlyReportDirtyWrites();
# endif /* XP_MACOSX */
/**
* Clear IO poisoning, this is only safe to do on the main-thread when no other
* threads are running.
* Never called! See bug 1647107.
*/
void ClearPoisonIOInterposer();
} // namespace mozilla
# endif /* __cplusplus */
#else /* defined(XP_MACOSX) || defined(XP_WIN) */
# ifdef __cplusplus
namespace mozilla {
inline bool IsDebugFile(intptr_t aFileID) { return true; }
inline void InitPoisonIOInterposer() {}
inline void ClearPoisonIOInterposer() {}
# ifdef XP_MACOSX
inline void OnlyReportDirtyWrites() {}
# endif /* XP_MACOSX */
} // namespace mozilla
# endif /* __cplusplus */
#endif /* XP_WIN || XP_MACOSX */
#endif // mozilla_PoisonIOInterposer_h