1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef BASE_PLATFORM_FILE_H_ 6 #define BASE_PLATFORM_FILE_H_ 7 8 #include "build/build_config.h" 9 #if defined(OS_WIN) 10 #include <windows.h> 11 #endif 12 13 #include <string> 14 15 #include "base/base_export.h" 16 #include "base/basictypes.h" 17 #include "base/files/file_path.h" 18 #include "base/time/time.h" 19 20 namespace base { 21 22 // PLATFORM_FILE_(OPEN|CREATE).* are mutually exclusive. You should specify 23 // exactly one of the five (possibly combining with other flags) when opening 24 // or creating a file. 25 // PLATFORM_FILE_(WRITE|APPEND) are mutually exclusive. This is so that APPEND 26 // behavior will be consistent with O_APPEND on POSIX. 27 enum PlatformFileFlags { 28 PLATFORM_FILE_OPEN = 1 << 0, // Opens a file, only if it exists. 29 PLATFORM_FILE_CREATE = 1 << 1, // Creates a new file, only if it 30 // does not already exist. 31 PLATFORM_FILE_OPEN_ALWAYS = 1 << 2, // May create a new file. 32 PLATFORM_FILE_CREATE_ALWAYS = 1 << 3, // May overwrite an old file. 33 PLATFORM_FILE_OPEN_TRUNCATED = 1 << 4, // Opens a file and truncates it, 34 // only if it exists. 35 PLATFORM_FILE_READ = 1 << 5, 36 PLATFORM_FILE_WRITE = 1 << 6, 37 PLATFORM_FILE_APPEND = 1 << 7, 38 PLATFORM_FILE_EXCLUSIVE_READ = 1 << 8, // EXCLUSIVE is opposite of Windows 39 // SHARE 40 PLATFORM_FILE_EXCLUSIVE_WRITE = 1 << 9, 41 PLATFORM_FILE_ASYNC = 1 << 10, 42 PLATFORM_FILE_TEMPORARY = 1 << 11, // Used on Windows only 43 PLATFORM_FILE_HIDDEN = 1 << 12, // Used on Windows only 44 PLATFORM_FILE_DELETE_ON_CLOSE = 1 << 13, 45 46 PLATFORM_FILE_WRITE_ATTRIBUTES = 1 << 14, // Used on Windows only 47 PLATFORM_FILE_ENUMERATE = 1 << 15, // May enumerate directory 48 49 PLATFORM_FILE_SHARE_DELETE = 1 << 16, // Used on Windows only 50 51 PLATFORM_FILE_TERMINAL_DEVICE = 1 << 17, // Serial port flags 52 PLATFORM_FILE_BACKUP_SEMANTICS = 1 << 18, // Used on Windows only 53 54 PLATFORM_FILE_EXECUTE = 1 << 19, // Used on Windows only 55 }; 56 57 // PLATFORM_FILE_ERROR_ACCESS_DENIED is returned when a call fails because of 58 // a filesystem restriction. PLATFORM_FILE_ERROR_SECURITY is returned when a 59 // browser policy doesn't allow the operation to be executed. 60 enum PlatformFileError { 61 PLATFORM_FILE_OK = 0, 62 PLATFORM_FILE_ERROR_FAILED = -1, 63 PLATFORM_FILE_ERROR_IN_USE = -2, 64 PLATFORM_FILE_ERROR_EXISTS = -3, 65 PLATFORM_FILE_ERROR_NOT_FOUND = -4, 66 PLATFORM_FILE_ERROR_ACCESS_DENIED = -5, 67 PLATFORM_FILE_ERROR_TOO_MANY_OPENED = -6, 68 PLATFORM_FILE_ERROR_NO_MEMORY = -7, 69 PLATFORM_FILE_ERROR_NO_SPACE = -8, 70 PLATFORM_FILE_ERROR_NOT_A_DIRECTORY = -9, 71 PLATFORM_FILE_ERROR_INVALID_OPERATION = -10, 72 PLATFORM_FILE_ERROR_SECURITY = -11, 73 PLATFORM_FILE_ERROR_ABORT = -12, 74 PLATFORM_FILE_ERROR_NOT_A_FILE = -13, 75 PLATFORM_FILE_ERROR_NOT_EMPTY = -14, 76 PLATFORM_FILE_ERROR_INVALID_URL = -15, 77 PLATFORM_FILE_ERROR_IO = -16, 78 // Put new entries here and increment PLATFORM_FILE_ERROR_MAX. 79 PLATFORM_FILE_ERROR_MAX = -17 80 }; 81 82 // This explicit mapping matches both FILE_ on Windows and SEEK_ on Linux. 83 enum PlatformFileWhence { 84 PLATFORM_FILE_FROM_BEGIN = 0, 85 PLATFORM_FILE_FROM_CURRENT = 1, 86 PLATFORM_FILE_FROM_END = 2 87 }; 88 89 // Used to hold information about a given file. 90 // If you add more fields to this structure (platform-specific fields are OK), 91 // make sure to update all functions that use it in file_util_{win|posix}.cc 92 // too, and the ParamTraits<base::PlatformFileInfo> implementation in 93 // chrome/common/common_param_traits.cc. 94 struct BASE_EXPORT PlatformFileInfo { 95 PlatformFileInfo(); 96 ~PlatformFileInfo(); 97 98 // The size of the file in bytes. Undefined when is_directory is true. 99 int64 size; 100 101 // True if the file corresponds to a directory. 102 bool is_directory; 103 104 // True if the file corresponds to a symbolic link. 105 bool is_symbolic_link; 106 107 // The last modified time of a file. 108 base::Time last_modified; 109 110 // The last accessed time of a file. 111 base::Time last_accessed; 112 113 // The creation time of a file. 114 base::Time creation_time; 115 }; 116 117 #if defined(OS_WIN) 118 typedef HANDLE PlatformFile; 119 const PlatformFile kInvalidPlatformFileValue = INVALID_HANDLE_VALUE; 120 PlatformFileError LastErrorToPlatformFileError(DWORD saved_errno); 121 #elif defined(OS_POSIX) 122 typedef int PlatformFile; 123 const PlatformFile kInvalidPlatformFileValue = -1; 124 PlatformFileError ErrnoToPlatformFileError(int saved_errno); 125 #endif 126 127 // Creates or opens the given file. If |created| is provided, it will be set to 128 // true if a new file was created [or an old one truncated to zero length to 129 // simulate a new file, which can happen with PLATFORM_FILE_CREATE_ALWAYS], and 130 // false otherwise. |error| can be NULL. 131 // 132 // This function fails with 'access denied' if the |name| contains path 133 // traversal ('..') components. 134 BASE_EXPORT PlatformFile CreatePlatformFile(const FilePath& name, 135 int flags, 136 bool* created, 137 PlatformFileError* error); 138 139 // Same as CreatePlatformFile but allows paths with traversal (like \..\) 140 // components. Use only with extreme care. 141 BASE_EXPORT PlatformFile CreatePlatformFileUnsafe(const FilePath& name, 142 int flags, 143 bool* created, 144 PlatformFileError* error); 145 146 BASE_EXPORT FILE* FdopenPlatformFile(PlatformFile file, const char* mode); 147 148 // Closes a file handle. Returns |true| on success and |false| otherwise. 149 BASE_EXPORT bool ClosePlatformFile(PlatformFile file); 150 151 // Changes current position in the file to an |offset| relative to an origin 152 // defined by |whence|. Returns the resultant current position in the file 153 // (relative to the start) or -1 in case of error. 154 BASE_EXPORT int64 SeekPlatformFile(PlatformFile file, 155 PlatformFileWhence whence, 156 int64 offset); 157 158 // Reads the given number of bytes (or until EOF is reached) starting with the 159 // given offset. Returns the number of bytes read, or -1 on error. Note that 160 // this function makes a best effort to read all data on all platforms, so it is 161 // not intended for stream oriented files but instead for cases when the normal 162 // expectation is that actually |size| bytes are read unless there is an error. 163 BASE_EXPORT int ReadPlatformFile(PlatformFile file, int64 offset, 164 char* data, int size); 165 166 // Same as above but without seek. 167 BASE_EXPORT int ReadPlatformFileAtCurrentPos(PlatformFile file, 168 char* data, int size); 169 170 // Reads the given number of bytes (or until EOF is reached) starting with the 171 // given offset, but does not make any effort to read all data on all platforms. 172 // Returns the number of bytes read, or -1 on error. 173 BASE_EXPORT int ReadPlatformFileNoBestEffort(PlatformFile file, int64 offset, 174 char* data, int size); 175 176 // Same as above but without seek. 177 BASE_EXPORT int ReadPlatformFileCurPosNoBestEffort(PlatformFile file, 178 char* data, int size); 179 180 // Writes the given buffer into the file at the given offset, overwritting any 181 // data that was previously there. Returns the number of bytes written, or -1 182 // on error. Note that this function makes a best effort to write all data on 183 // all platforms. 184 // Ignores the offset and writes to the end of the file if the file was opened 185 // with PLATFORM_FILE_APPEND. 186 BASE_EXPORT int WritePlatformFile(PlatformFile file, int64 offset, 187 const char* data, int size); 188 189 // Save as above but without seek. 190 BASE_EXPORT int WritePlatformFileAtCurrentPos(PlatformFile file, 191 const char* data, int size); 192 193 // Save as above but does not make any effort to write all data on all 194 // platforms. Returns the number of bytes written, or -1 on error. 195 BASE_EXPORT int WritePlatformFileCurPosNoBestEffort(PlatformFile file, 196 const char* data, int size); 197 198 // Truncates the given file to the given length. If |length| is greater than 199 // the current size of the file, the file is extended with zeros. If the file 200 // doesn't exist, |false| is returned. 201 BASE_EXPORT bool TruncatePlatformFile(PlatformFile file, int64 length); 202 203 // Flushes the buffers of the given file. 204 BASE_EXPORT bool FlushPlatformFile(PlatformFile file); 205 206 // Touches the given file. 207 BASE_EXPORT bool TouchPlatformFile(PlatformFile file, 208 const Time& last_access_time, 209 const Time& last_modified_time); 210 211 // Returns some information for the given file. 212 BASE_EXPORT bool GetPlatformFileInfo(PlatformFile file, PlatformFileInfo* info); 213 214 // Use this class to pass ownership of a PlatformFile to a receiver that may or 215 // may not want to accept it. This class does not own the storage for the 216 // PlatformFile. 217 // 218 // EXAMPLE: 219 // 220 // void MaybeProcessFile(PassPlatformFile pass_file) { 221 // if (...) { 222 // PlatformFile file = pass_file.ReleaseValue(); 223 // // Now, we are responsible for closing |file|. 224 // } 225 // } 226 // 227 // void OpenAndMaybeProcessFile(const FilePath& path) { 228 // PlatformFile file = CreatePlatformFile(path, ...); 229 // MaybeProcessFile(PassPlatformFile(&file)); 230 // if (file != kInvalidPlatformFileValue) 231 // ClosePlatformFile(file); 232 // } 233 // 234 class BASE_EXPORT PassPlatformFile { 235 public: 236 explicit PassPlatformFile(PlatformFile* value) : value_(value) { 237 } 238 239 // Called to retrieve the PlatformFile stored in this object. The caller 240 // gains ownership of the PlatformFile and is now responsible for closing it. 241 // Any subsequent calls to this method will return an invalid PlatformFile. 242 PlatformFile ReleaseValue() { 243 PlatformFile temp = *value_; 244 *value_ = kInvalidPlatformFileValue; 245 return temp; 246 } 247 248 private: 249 PlatformFile* value_; 250 }; 251 252 } // namespace base 253 254 #endif // BASE_PLATFORM_FILE_H_ 255
