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