255 lines
10 KiB
C++
255 lines
10 KiB
C++
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BASE_PLATFORM_FILE_H_
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#define BASE_PLATFORM_FILE_H_
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#include "build/build_config.h"
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#if defined(OS_WIN)
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#include <windows.h>
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#endif
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#include <string>
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#include "base/base_export.h"
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#include "base/basictypes.h"
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#include "base/files/file_path.h"
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#include "base/time/time.h"
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namespace base {
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// PLATFORM_FILE_(OPEN|CREATE).* are mutually exclusive. You should specify
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// exactly one of the five (possibly combining with other flags) when opening
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// or creating a file.
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// PLATFORM_FILE_(WRITE|APPEND) are mutually exclusive. This is so that APPEND
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// behavior will be consistent with O_APPEND on POSIX.
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enum PlatformFileFlags {
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PLATFORM_FILE_OPEN = 1 << 0, // Opens a file, only if it exists.
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PLATFORM_FILE_CREATE = 1 << 1, // Creates a new file, only if it
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// does not already exist.
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PLATFORM_FILE_OPEN_ALWAYS = 1 << 2, // May create a new file.
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PLATFORM_FILE_CREATE_ALWAYS = 1 << 3, // May overwrite an old file.
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PLATFORM_FILE_OPEN_TRUNCATED = 1 << 4, // Opens a file and truncates it,
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// only if it exists.
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PLATFORM_FILE_READ = 1 << 5,
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PLATFORM_FILE_WRITE = 1 << 6,
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PLATFORM_FILE_APPEND = 1 << 7,
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PLATFORM_FILE_EXCLUSIVE_READ = 1 << 8, // EXCLUSIVE is opposite of Windows
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// SHARE
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PLATFORM_FILE_EXCLUSIVE_WRITE = 1 << 9,
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PLATFORM_FILE_ASYNC = 1 << 10,
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PLATFORM_FILE_TEMPORARY = 1 << 11, // Used on Windows only
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PLATFORM_FILE_HIDDEN = 1 << 12, // Used on Windows only
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PLATFORM_FILE_DELETE_ON_CLOSE = 1 << 13,
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PLATFORM_FILE_WRITE_ATTRIBUTES = 1 << 14, // Used on Windows only
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PLATFORM_FILE_ENUMERATE = 1 << 15, // May enumerate directory
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PLATFORM_FILE_SHARE_DELETE = 1 << 16, // Used on Windows only
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PLATFORM_FILE_TERMINAL_DEVICE = 1 << 17, // Serial port flags
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PLATFORM_FILE_BACKUP_SEMANTICS = 1 << 18, // Used on Windows only
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PLATFORM_FILE_EXECUTE = 1 << 19, // Used on Windows only
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};
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// PLATFORM_FILE_ERROR_ACCESS_DENIED is returned when a call fails because of
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// a filesystem restriction. PLATFORM_FILE_ERROR_SECURITY is returned when a
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// browser policy doesn't allow the operation to be executed.
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enum PlatformFileError {
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PLATFORM_FILE_OK = 0,
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PLATFORM_FILE_ERROR_FAILED = -1,
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PLATFORM_FILE_ERROR_IN_USE = -2,
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PLATFORM_FILE_ERROR_EXISTS = -3,
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PLATFORM_FILE_ERROR_NOT_FOUND = -4,
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PLATFORM_FILE_ERROR_ACCESS_DENIED = -5,
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PLATFORM_FILE_ERROR_TOO_MANY_OPENED = -6,
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PLATFORM_FILE_ERROR_NO_MEMORY = -7,
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PLATFORM_FILE_ERROR_NO_SPACE = -8,
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PLATFORM_FILE_ERROR_NOT_A_DIRECTORY = -9,
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PLATFORM_FILE_ERROR_INVALID_OPERATION = -10,
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PLATFORM_FILE_ERROR_SECURITY = -11,
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PLATFORM_FILE_ERROR_ABORT = -12,
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PLATFORM_FILE_ERROR_NOT_A_FILE = -13,
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PLATFORM_FILE_ERROR_NOT_EMPTY = -14,
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PLATFORM_FILE_ERROR_INVALID_URL = -15,
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PLATFORM_FILE_ERROR_IO = -16,
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// Put new entries here and increment PLATFORM_FILE_ERROR_MAX.
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PLATFORM_FILE_ERROR_MAX = -17
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};
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// This explicit mapping matches both FILE_ on Windows and SEEK_ on Linux.
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enum PlatformFileWhence {
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PLATFORM_FILE_FROM_BEGIN = 0,
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PLATFORM_FILE_FROM_CURRENT = 1,
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PLATFORM_FILE_FROM_END = 2
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};
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// Used to hold information about a given file.
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// If you add more fields to this structure (platform-specific fields are OK),
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// make sure to update all functions that use it in file_util_{win|posix}.cc
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// too, and the ParamTraits<base::PlatformFileInfo> implementation in
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// chrome/common/common_param_traits.cc.
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struct BASE_EXPORT PlatformFileInfo {
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PlatformFileInfo();
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~PlatformFileInfo();
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// The size of the file in bytes. Undefined when is_directory is true.
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int64 size;
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// True if the file corresponds to a directory.
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bool is_directory;
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// True if the file corresponds to a symbolic link.
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bool is_symbolic_link;
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// The last modified time of a file.
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base::Time last_modified;
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// The last accessed time of a file.
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base::Time last_accessed;
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// The creation time of a file.
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base::Time creation_time;
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};
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#if defined(OS_WIN)
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typedef HANDLE PlatformFile;
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const PlatformFile kInvalidPlatformFileValue = INVALID_HANDLE_VALUE;
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PlatformFileError LastErrorToPlatformFileError(DWORD saved_errno);
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#elif defined(OS_POSIX)
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typedef int PlatformFile;
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const PlatformFile kInvalidPlatformFileValue = -1;
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PlatformFileError ErrnoToPlatformFileError(int saved_errno);
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#endif
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// Creates or opens the given file. If |created| is provided, it will be set to
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// true if a new file was created [or an old one truncated to zero length to
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// simulate a new file, which can happen with PLATFORM_FILE_CREATE_ALWAYS], and
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// false otherwise. |error| can be NULL.
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//
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// This function fails with 'access denied' if the |name| contains path
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// traversal ('..') components.
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BASE_EXPORT PlatformFile CreatePlatformFile(const FilePath& name,
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int flags,
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bool* created,
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PlatformFileError* error);
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// Same as CreatePlatformFile but allows paths with traversal (like \..\)
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// components. Use only with extreme care.
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BASE_EXPORT PlatformFile CreatePlatformFileUnsafe(const FilePath& name,
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int flags,
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bool* created,
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PlatformFileError* error);
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BASE_EXPORT FILE* FdopenPlatformFile(PlatformFile file, const char* mode);
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// Closes a file handle. Returns |true| on success and |false| otherwise.
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BASE_EXPORT bool ClosePlatformFile(PlatformFile file);
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// Changes current position in the file to an |offset| relative to an origin
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// defined by |whence|. Returns the resultant current position in the file
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// (relative to the start) or -1 in case of error.
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BASE_EXPORT int64 SeekPlatformFile(PlatformFile file,
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PlatformFileWhence whence,
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int64 offset);
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// Reads the given number of bytes (or until EOF is reached) starting with the
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// given offset. Returns the number of bytes read, or -1 on error. Note that
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// this function makes a best effort to read all data on all platforms, so it is
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// not intended for stream oriented files but instead for cases when the normal
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// expectation is that actually |size| bytes are read unless there is an error.
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BASE_EXPORT int ReadPlatformFile(PlatformFile file, int64 offset,
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char* data, int size);
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// Same as above but without seek.
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BASE_EXPORT int ReadPlatformFileAtCurrentPos(PlatformFile file,
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char* data, int size);
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// Reads the given number of bytes (or until EOF is reached) starting with the
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// given offset, but does not make any effort to read all data on all platforms.
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// Returns the number of bytes read, or -1 on error.
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BASE_EXPORT int ReadPlatformFileNoBestEffort(PlatformFile file, int64 offset,
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char* data, int size);
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// Same as above but without seek.
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BASE_EXPORT int ReadPlatformFileCurPosNoBestEffort(PlatformFile file,
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char* data, int size);
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// Writes the given buffer into the file at the given offset, overwritting any
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// data that was previously there. Returns the number of bytes written, or -1
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// on error. Note that this function makes a best effort to write all data on
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// all platforms.
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// Ignores the offset and writes to the end of the file if the file was opened
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// with PLATFORM_FILE_APPEND.
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BASE_EXPORT int WritePlatformFile(PlatformFile file, int64 offset,
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const char* data, int size);
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// Save as above but without seek.
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BASE_EXPORT int WritePlatformFileAtCurrentPos(PlatformFile file,
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const char* data, int size);
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// Save as above but does not make any effort to write all data on all
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// platforms. Returns the number of bytes written, or -1 on error.
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BASE_EXPORT int WritePlatformFileCurPosNoBestEffort(PlatformFile file,
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const char* data, int size);
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// Truncates the given file to the given length. If |length| is greater than
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// the current size of the file, the file is extended with zeros. If the file
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// doesn't exist, |false| is returned.
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BASE_EXPORT bool TruncatePlatformFile(PlatformFile file, int64 length);
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// Flushes the buffers of the given file.
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BASE_EXPORT bool FlushPlatformFile(PlatformFile file);
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// Touches the given file.
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BASE_EXPORT bool TouchPlatformFile(PlatformFile file,
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const Time& last_access_time,
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const Time& last_modified_time);
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// Returns some information for the given file.
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BASE_EXPORT bool GetPlatformFileInfo(PlatformFile file, PlatformFileInfo* info);
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// Use this class to pass ownership of a PlatformFile to a receiver that may or
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// may not want to accept it. This class does not own the storage for the
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// PlatformFile.
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//
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// EXAMPLE:
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//
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// void MaybeProcessFile(PassPlatformFile pass_file) {
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// if (...) {
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// PlatformFile file = pass_file.ReleaseValue();
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// // Now, we are responsible for closing |file|.
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// }
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// }
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//
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// void OpenAndMaybeProcessFile(const FilePath& path) {
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// PlatformFile file = CreatePlatformFile(path, ...);
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// MaybeProcessFile(PassPlatformFile(&file));
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// if (file != kInvalidPlatformFileValue)
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// ClosePlatformFile(file);
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// }
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//
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class BASE_EXPORT PassPlatformFile {
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public:
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explicit PassPlatformFile(PlatformFile* value) : value_(value) {
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}
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// Called to retrieve the PlatformFile stored in this object. The caller
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// gains ownership of the PlatformFile and is now responsible for closing it.
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// Any subsequent calls to this method will return an invalid PlatformFile.
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PlatformFile ReleaseValue() {
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PlatformFile temp = *value_;
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*value_ = kInvalidPlatformFileValue;
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return temp;
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}
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private:
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PlatformFile* value_;
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};
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} // namespace base
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#endif // BASE_PLATFORM_FILE_H_
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