mirror of
https://github.com/classilla/tenfourfox.git
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215 lines
6.6 KiB
C++
215 lines
6.6 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_FileUtils_h
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#define mozilla_FileUtils_h
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#include "nscore.h" // nullptr
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#if defined(XP_UNIX)
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# include <unistd.h>
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#elif defined(XP_WIN)
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# include <io.h>
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#endif
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#include "prio.h"
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#include "mozilla/Scoped.h"
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#include "nsIFile.h"
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#include <errno.h>
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#include <limits.h>
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namespace mozilla {
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#if defined(XP_WIN)
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typedef void* filedesc_t;
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typedef const wchar_t* pathstr_t;
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#else
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typedef int filedesc_t;
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typedef const char* pathstr_t;
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#endif
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/**
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* ScopedCloseFD is a RAII wrapper for POSIX file descriptors
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*
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* Instances |close()| their fds when they go out of scope.
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*/
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struct ScopedCloseFDTraits
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{
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typedef int type;
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static type empty() { return -1; }
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static void release(type aFd)
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{
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if (aFd != -1) {
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while (close(aFd) == -1 && errno == EINTR) {
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}
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}
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}
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};
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typedef Scoped<ScopedCloseFDTraits> ScopedClose;
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#if !defined(XPCOM_GLUE)
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/**
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* AutoFDClose is a RAII wrapper for PRFileDesc.
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*
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* Instances |PR_Close| their fds when they go out of scope.
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**/
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struct ScopedClosePRFDTraits
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{
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typedef PRFileDesc* type;
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static type empty() { return nullptr; }
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static void release(type aFd)
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{
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if (aFd) {
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PR_Close(aFd);
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}
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}
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};
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typedef Scoped<ScopedClosePRFDTraits> AutoFDClose;
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/* RAII wrapper for FILE descriptors */
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struct ScopedCloseFileTraits
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{
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typedef FILE* type;
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static type empty() { return nullptr; }
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static void release(type aFile)
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{
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if (aFile) {
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fclose(aFile);
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}
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}
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};
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typedef Scoped<ScopedCloseFileTraits> ScopedCloseFile;
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/**
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* Fallocate efficiently and continuously allocates files via fallocate-type APIs.
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* This is useful for avoiding fragmentation.
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* On sucess the file be padded with zeros to grow to aLength.
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*
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* @param aFD file descriptor.
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* @param aLength length of file to grow to.
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* @return true on success.
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*/
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bool fallocate(PRFileDesc* aFD, int64_t aLength);
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/**
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* Use readahead to preload shared libraries into the file cache before loading.
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* WARNING: This function should not be used without a telemetry field trial
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* demonstrating a clear performance improvement!
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*
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* @param aFile nsIFile representing path to shared library
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*/
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void ReadAheadLib(nsIFile* aFile);
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/**
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* Use readahead to preload a file into the file cache before reading.
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* WARNING: This function should not be used without a telemetry field trial
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* demonstrating a clear performance improvement!
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*
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* @param aFile nsIFile representing path to shared library
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* @param aOffset Offset into the file to begin preloading
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* @param aCount Number of bytes to preload (SIZE_MAX implies file size)
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* @param aOutFd Pointer to file descriptor. If specified, ReadAheadFile will
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* return its internal, opened file descriptor instead of closing it.
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*/
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void ReadAheadFile(nsIFile* aFile, const size_t aOffset = 0,
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const size_t aCount = SIZE_MAX,
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filedesc_t* aOutFd = nullptr);
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#endif // !defined(XPCOM_GLUE)
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/**
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* Use readahead to preload shared libraries into the file cache before loading.
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* WARNING: This function should not be used without a telemetry field trial
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* demonstrating a clear performance improvement!
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*
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* @param aFilePath path to shared library
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*/
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void ReadAheadLib(pathstr_t aFilePath);
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/**
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* Use readahead to preload a file into the file cache before loading.
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* WARNING: This function should not be used without a telemetry field trial
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* demonstrating a clear performance improvement!
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*
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* @param aFilePath path to shared library
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* @param aOffset Offset into the file to begin preloading
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* @param aCount Number of bytes to preload (SIZE_MAX implies file size)
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* @param aOutFd Pointer to file descriptor. If specified, ReadAheadFile will
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* return its internal, opened file descriptor instead of closing it.
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*/
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void ReadAheadFile(pathstr_t aFilePath, const size_t aOffset = 0,
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const size_t aCount = SIZE_MAX,
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filedesc_t* aOutFd = nullptr);
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/**
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* Use readahead to preload a file into the file cache before reading.
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* When this function exits, the file pointer is guaranteed to be in the same
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* position it was in before this function was called.
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* WARNING: This function should not be used without a telemetry field trial
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* demonstrating a clear performance improvement!
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*
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* @param aFd file descriptor opened for read access
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* (on Windows, file must be opened with FILE_FLAG_SEQUENTIAL_SCAN)
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* @param aOffset Offset into the file to begin preloading
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* @param aCount Number of bytes to preload (SIZE_MAX implies file size)
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*/
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void ReadAhead(filedesc_t aFd, const size_t aOffset = 0,
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const size_t aCount = SIZE_MAX);
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#if defined(MOZ_WIDGET_GONK) || defined(XP_UNIX)
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#define MOZ_TEMP_FAILURE_RETRY(exp) (__extension__({ \
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typeof (exp) _rc; \
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do { \
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_rc = (exp); \
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} while (_rc == -1 && errno == EINTR); \
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_rc; \
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}))
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#endif
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/* Define ReadSysFile() only on GONK to avoid unnecessary lubxul bloat.
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Also define it in debug builds, so that unit tests for it can be written
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and run in non-GONK builds. */
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#if (defined(MOZ_WIDGET_GONK) || defined(DEBUG)) && defined(XP_UNIX)
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#ifndef ReadSysFile_PRESENT
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#define ReadSysFile_PRESENT
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#endif /* ReadSysFile_PRESENT */
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/**
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* Read the contents of a file.
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* This function is intended for reading a single-lined text files from
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* /sys/. If the file ends with a newline ('\n') then it will be discarded.
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* The output buffer will always be '\0'-terminated on successful completion.
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* If aBufSize == 0, then this function will return true if the file exists
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* and is readable (it will not attempt to read anything from it).
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* On failure the contents of aBuf after this call will be undefined and the
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* value of the global variable errno will be set accordingly.
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* @return true on success, notice that less than requested bytes could have
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* been read if the file was smaller
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*/
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bool ReadSysFile(const char* aFilename, char* aBuf, size_t aBufSize);
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/**
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* Parse the contents of a file, assuming it contains a decimal integer.
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* @return true on success
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*/
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bool ReadSysFile(const char* aFilename, int* aVal);
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/**
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* Parse the contents of a file, assuming it contains a boolean value
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* (either 0 or 1).
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* @return true on success
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*/
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bool ReadSysFile(const char* aFilename, bool* aVal);
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#endif /* (MOZ_WIDGET_GONK || DEBUG) && XP_UNIX */
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} // namespace mozilla
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#endif
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