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mbed 2

This is the mbed 2 library. If you'd like to learn about Mbed OS please see the mbed-os docs.

platform/FileHandle.h@172:65be27845400, 2019-02-20 (annotated)

Committer:
AnnaBridge
Date:
Wed Feb 20 20:53:29 2019 +0000
Revision:
172:65be27845400
Parent:
171:3a7713b1edbc 
mbed library release version 165

Who changed what in which revision?

UserRevisionLine numberNew contents of line
AnnaBridge 156:ff21514d8981 1 /* mbed Microcontroller Library
AnnaBridge 156:ff21514d8981 2 * Copyright (c) 2017 ARM Limited
AnnaBridge 172:65be27845400 3 * SPDX-License-Identifier: Apache-2.0
AnnaBridge 156:ff21514d8981 4 *
AnnaBridge 156:ff21514d8981 5 * Licensed under the Apache License, Version 2.0 (the "License");
AnnaBridge 156:ff21514d8981 6 * you may not use this file except in compliance with the License.
AnnaBridge 156:ff21514d8981 7 * You may obtain a copy of the License at
AnnaBridge 156:ff21514d8981 8 *
AnnaBridge 156:ff21514d8981 9 * http://www.apache.org/licenses/LICENSE-2.0
AnnaBridge 156:ff21514d8981 10 *
AnnaBridge 156:ff21514d8981 11 * Unless required by applicable law or agreed to in writing, software
AnnaBridge 156:ff21514d8981 12 * distributed under the License is distributed on an "AS IS" BASIS,
AnnaBridge 156:ff21514d8981 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
AnnaBridge 156:ff21514d8981 14 * See the License for the specific language governing permissions and
AnnaBridge 156:ff21514d8981 15 * limitations under the License.
AnnaBridge 156:ff21514d8981 16 */
AnnaBridge 156:ff21514d8981 17 #ifndef MBED_FILEHANDLE_H
AnnaBridge 156:ff21514d8981 18 #define MBED_FILEHANDLE_H
AnnaBridge 156:ff21514d8981 19
AnnaBridge 156:ff21514d8981 20 typedef int FILEHANDLE;
AnnaBridge 156:ff21514d8981 21
AnnaBridge 156:ff21514d8981 22 #include <cstdio>
AnnaBridge 156:ff21514d8981 23 #include "Callback.h"
AnnaBridge 156:ff21514d8981 24 #include "platform/mbed_poll.h"
AnnaBridge 156:ff21514d8981 25 #include "platform/platform.h"
AnnaBridge 156:ff21514d8981 26 #include "platform/NonCopyable.h"
AnnaBridge 156:ff21514d8981 27
AnnaBridge 156:ff21514d8981 28 namespace mbed {
AnnaBridge 156:ff21514d8981 29 /** \addtogroup platform */
AnnaBridge 158:1c57384330a6 30 /** @{*/
AnnaBridge 158:1c57384330a6 31 /**
AnnaBridge 158:1c57384330a6 32 * \defgroup platform_FileHandle FileHandle functions
AnnaBridge 158:1c57384330a6 33 * @{
AnnaBridge 158:1c57384330a6 34 */
AnnaBridge 156:ff21514d8981 35
AnnaBridge 156:ff21514d8981 36
AnnaBridge 156:ff21514d8981 37 /** Class FileHandle
AnnaBridge 156:ff21514d8981 38 *
AnnaBridge 156:ff21514d8981 39 * An abstract interface that represents operations on a file-like
AnnaBridge 171:3a7713b1edbc 40 * object. The core functions are read, write and seek, but only
AnnaBridge 156:ff21514d8981 41 * a subset of these operations can be provided.
AnnaBridge 156:ff21514d8981 42 *
AnnaBridge 156:ff21514d8981 43 * @note to create a file, @see File
AnnaBridge 156:ff21514d8981 44 * @note Synchronization level: Set by subclass
AnnaBridge 156:ff21514d8981 45 */
AnnaBridge 156:ff21514d8981 46 class FileHandle : private NonCopyable<FileHandle> {
AnnaBridge 156:ff21514d8981 47 public:
AnnaBridge 156:ff21514d8981 48 virtual ~FileHandle() {}
AnnaBridge 156:ff21514d8981 49
AnnaBridge 156:ff21514d8981 50 /** Read the contents of a file into a buffer
AnnaBridge 156:ff21514d8981 51 *
AnnaBridge 156:ff21514d8981 52 * Devices acting as FileHandles should follow POSIX semantics:
AnnaBridge 156:ff21514d8981 53 *
AnnaBridge 171:3a7713b1edbc 54 * * if no data is available, and nonblocking set, return -EAGAIN
Anna Bridge 160:5571c4ff569f 55 * * if no data is available, and blocking set, wait until some data is available
AnnaBridge 156:ff21514d8981 56 * * If any data is available, call returns immediately
AnnaBridge 156:ff21514d8981 57 *
AnnaBridge 156:ff21514d8981 58 * @param buffer The buffer to read in to
AnnaBridge 156:ff21514d8981 59 * @param size The number of bytes to read
AnnaBridge 156:ff21514d8981 60 * @return The number of bytes read, 0 at end of file, negative error on failure
AnnaBridge 156:ff21514d8981 61 */
AnnaBridge 156:ff21514d8981 62 virtual ssize_t read(void *buffer, size_t size) = 0;
AnnaBridge 156:ff21514d8981 63
AnnaBridge 156:ff21514d8981 64 /** Write the contents of a buffer to a file
AnnaBridge 156:ff21514d8981 65 *
Anna Bridge 160:5571c4ff569f 66 * Devices acting as FileHandles should follow POSIX semantics:
Anna Bridge 160:5571c4ff569f 67 *
Anna Bridge 160:5571c4ff569f 68 * * if blocking, block until all data is written
AnnaBridge 171:3a7713b1edbc 69 * * if no data can be written, and nonblocking set, return -EAGAIN
AnnaBridge 171:3a7713b1edbc 70 * * if some data can be written, and nonblocking set, write partial
Anna Bridge 160:5571c4ff569f 71 *
AnnaBridge 156:ff21514d8981 72 * @param buffer The buffer to write from
AnnaBridge 170:e95d10626187 73 * @param size The number of bytes to write
AnnaBridge 156:ff21514d8981 74 * @return The number of bytes written, negative error on failure
AnnaBridge 156:ff21514d8981 75 */
AnnaBridge 156:ff21514d8981 76 virtual ssize_t write(const void *buffer, size_t size) = 0;
AnnaBridge 156:ff21514d8981 77
AnnaBridge 156:ff21514d8981 78 /** Move the file position to a given offset from from a given location
AnnaBridge 156:ff21514d8981 79 *
AnnaBridge 156:ff21514d8981 80 * @param offset The offset from whence to move to
AnnaBridge 156:ff21514d8981 81 * @param whence The start of where to seek
AnnaBridge 156:ff21514d8981 82 * SEEK_SET to start from beginning of file,
AnnaBridge 156:ff21514d8981 83 * SEEK_CUR to start from current position in file,
AnnaBridge 156:ff21514d8981 84 * SEEK_END to start from end of file
AnnaBridge 156:ff21514d8981 85 * @return The new offset of the file, negative error code on failure
AnnaBridge 156:ff21514d8981 86 */
AnnaBridge 156:ff21514d8981 87 virtual off_t seek(off_t offset, int whence = SEEK_SET) = 0;
AnnaBridge 156:ff21514d8981 88
AnnaBridge 156:ff21514d8981 89 /** Close a file
AnnaBridge 156:ff21514d8981 90 *
AnnaBridge 156:ff21514d8981 91 * @return 0 on success, negative error code on failure
AnnaBridge 156:ff21514d8981 92 */
AnnaBridge 156:ff21514d8981 93 virtual int close() = 0;
AnnaBridge 156:ff21514d8981 94
AnnaBridge 156:ff21514d8981 95 /** Flush any buffers associated with the file
AnnaBridge 156:ff21514d8981 96 *
AnnaBridge 156:ff21514d8981 97 * @return 0 on success, negative error code on failure
AnnaBridge 156:ff21514d8981 98 */
AnnaBridge 156:ff21514d8981 99 virtual int sync()
AnnaBridge 156:ff21514d8981 100 {
AnnaBridge 156:ff21514d8981 101 return 0;
AnnaBridge 156:ff21514d8981 102 }
AnnaBridge 156:ff21514d8981 103
AnnaBridge 156:ff21514d8981 104 /** Check if the file in an interactive terminal device
AnnaBridge 156:ff21514d8981 105 *
AnnaBridge 156:ff21514d8981 106 * @return True if the file is a terminal
AnnaBridge 156:ff21514d8981 107 * @return False if the file is not a terminal
AnnaBridge 156:ff21514d8981 108 * @return Negative error code on failure
AnnaBridge 156:ff21514d8981 109 */
AnnaBridge 156:ff21514d8981 110 virtual int isatty()
AnnaBridge 156:ff21514d8981 111 {
AnnaBridge 156:ff21514d8981 112 return false;
AnnaBridge 156:ff21514d8981 113 }
AnnaBridge 156:ff21514d8981 114
AnnaBridge 156:ff21514d8981 115 /** Get the file position of the file
AnnaBridge 156:ff21514d8981 116 *
AnnaBridge 156:ff21514d8981 117 * @note This is equivalent to seek(0, SEEK_CUR)
AnnaBridge 156:ff21514d8981 118 *
AnnaBridge 156:ff21514d8981 119 * @return The current offset in the file, negative error code on failure
AnnaBridge 156:ff21514d8981 120 */
AnnaBridge 156:ff21514d8981 121 virtual off_t tell()
AnnaBridge 156:ff21514d8981 122 {
AnnaBridge 156:ff21514d8981 123 return seek(0, SEEK_CUR);
AnnaBridge 156:ff21514d8981 124 }
AnnaBridge 156:ff21514d8981 125
AnnaBridge 156:ff21514d8981 126 /** Rewind the file position to the beginning of the file
AnnaBridge 156:ff21514d8981 127 *
AnnaBridge 156:ff21514d8981 128 * @note This is equivalent to seek(0, SEEK_SET)
AnnaBridge 156:ff21514d8981 129 */
AnnaBridge 156:ff21514d8981 130 virtual void rewind()
AnnaBridge 156:ff21514d8981 131 {
AnnaBridge 156:ff21514d8981 132 seek(0, SEEK_SET);
AnnaBridge 156:ff21514d8981 133 }
AnnaBridge 156:ff21514d8981 134
AnnaBridge 156:ff21514d8981 135 /** Get the size of the file
AnnaBridge 156:ff21514d8981 136 *
AnnaBridge 156:ff21514d8981 137 * @return Size of the file in bytes
AnnaBridge 156:ff21514d8981 138 */
AnnaBridge 156:ff21514d8981 139 virtual off_t size();
AnnaBridge 156:ff21514d8981 140
AnnaBridge 156:ff21514d8981 141 /** Move the file position to a given offset from a given location.
AnnaBridge 156:ff21514d8981 142 *
AnnaBridge 156:ff21514d8981 143 * @param offset The offset from whence to move to
AnnaBridge 156:ff21514d8981 144 * @param whence SEEK_SET for the start of the file, SEEK_CUR for the
AnnaBridge 156:ff21514d8981 145 * current file position, or SEEK_END for the end of the file.
AnnaBridge 156:ff21514d8981 146 *
AnnaBridge 156:ff21514d8981 147 * @returns
AnnaBridge 156:ff21514d8981 148 * new file position on success,
AnnaBridge 156:ff21514d8981 149 * -1 on failure or unsupported
AnnaBridge 167:84c0a372a020 150 * @deprecated Replaced by `off_t FileHandle::seek(off_t offset, int whence = SEEK_SET)'
AnnaBridge 167:84c0a372a020 151 *
AnnaBridge 156:ff21514d8981 152 */
AnnaBridge 156:ff21514d8981 153 MBED_DEPRECATED_SINCE("mbed-os-5.4", "Replaced by FileHandle::seek")
AnnaBridge 156:ff21514d8981 154 virtual off_t lseek(off_t offset, int whence)
AnnaBridge 156:ff21514d8981 155 {
AnnaBridge 156:ff21514d8981 156 return seek(offset, whence);
AnnaBridge 156:ff21514d8981 157 }
AnnaBridge 156:ff21514d8981 158
AnnaBridge 156:ff21514d8981 159 /** Flush any buffers associated with the FileHandle, ensuring it
AnnaBridge 156:ff21514d8981 160 * is up to date on disk
AnnaBridge 156:ff21514d8981 161 *
AnnaBridge 156:ff21514d8981 162 * @returns
AnnaBridge 156:ff21514d8981 163 * 0 on success or un-needed,
AnnaBridge 156:ff21514d8981 164 * -1 on error
AnnaBridge 167:84c0a372a020 165 * @deprecated Replaced by `int FileHandle::sync()'
AnnaBridge 156:ff21514d8981 166 */
AnnaBridge 156:ff21514d8981 167 MBED_DEPRECATED_SINCE("mbed-os-5.4", "Replaced by FileHandle::sync")
AnnaBridge 156:ff21514d8981 168 virtual int fsync()
AnnaBridge 156:ff21514d8981 169 {
AnnaBridge 156:ff21514d8981 170 return sync();
AnnaBridge 156:ff21514d8981 171 }
AnnaBridge 156:ff21514d8981 172
AnnaBridge 156:ff21514d8981 173 /** Find the length of the file
AnnaBridge 156:ff21514d8981 174 *
AnnaBridge 156:ff21514d8981 175 * @returns
AnnaBridge 156:ff21514d8981 176 * Length of the file
AnnaBridge 167:84c0a372a020 177 * @deprecated Replaced by `off_t FileHandle::size()'
AnnaBridge 156:ff21514d8981 178 */
AnnaBridge 156:ff21514d8981 179 MBED_DEPRECATED_SINCE("mbed-os-5.4", "Replaced by FileHandle::size")
AnnaBridge 156:ff21514d8981 180 virtual off_t flen()
AnnaBridge 156:ff21514d8981 181 {
AnnaBridge 156:ff21514d8981 182 return size();
AnnaBridge 156:ff21514d8981 183 }
AnnaBridge 156:ff21514d8981 184
AnnaBridge 171:3a7713b1edbc 185 /** Set blocking or nonblocking mode of the file operation like read/write.
AnnaBridge 171:3a7713b1edbc 186 * Definition depends on the subclass implementing FileHandle.
AnnaBridge 156:ff21514d8981 187 * The default is blocking.
AnnaBridge 156:ff21514d8981 188 *
AnnaBridge 171:3a7713b1edbc 189 * @param blocking true for blocking mode, false for nonblocking mode.
AnnaBridge 156:ff21514d8981 190 *
AnnaBridge 156:ff21514d8981 191 * @return 0 on success
AnnaBridge 156:ff21514d8981 192 * @return Negative error code on failure
AnnaBridge 156:ff21514d8981 193 */
AnnaBridge 156:ff21514d8981 194 virtual int set_blocking(bool blocking)
AnnaBridge 156:ff21514d8981 195 {
Anna Bridge 169:a7c7b631e539 196 return blocking ? 0 : -ENOTTY;
Anna Bridge 169:a7c7b631e539 197 }
Anna Bridge 169:a7c7b631e539 198
AnnaBridge 171:3a7713b1edbc 199 /** Check current blocking or nonblocking mode for file operations.
Anna Bridge 169:a7c7b631e539 200 *
AnnaBridge 171:3a7713b1edbc 201 * @return true for blocking mode, false for nonblocking mode.
Anna Bridge 169:a7c7b631e539 202 */
Anna Bridge 169:a7c7b631e539 203 virtual bool is_blocking() const
Anna Bridge 169:a7c7b631e539 204 {
Anna Bridge 169:a7c7b631e539 205 return true;
AnnaBridge 156:ff21514d8981 206 }
AnnaBridge 156:ff21514d8981 207
AnnaBridge 156:ff21514d8981 208 /** Check for poll event flags
AnnaBridge 171:3a7713b1edbc 209 * You can use or ignore the input parameter. You can return all events
AnnaBridge 171:3a7713b1edbc 210 * or check just the events listed in events.
AnnaBridge 171:3a7713b1edbc 211 * Call is nonblocking - returns instantaneous state of events.
AnnaBridge 156:ff21514d8981 212 * Whenever an event occurs, the derived class should call the sigio() callback).
AnnaBridge 156:ff21514d8981 213 *
AnnaBridge 156:ff21514d8981 214 * @param events bitmask of poll events we're interested in - POLLIN/POLLOUT etc.
AnnaBridge 156:ff21514d8981 215 *
AnnaBridge 156:ff21514d8981 216 * @returns bitmask of poll events that have occurred.
AnnaBridge 156:ff21514d8981 217 */
AnnaBridge 156:ff21514d8981 218 virtual short poll(short events) const
AnnaBridge 156:ff21514d8981 219 {
AnnaBridge 156:ff21514d8981 220 // Possible default for real files
AnnaBridge 156:ff21514d8981 221 return POLLIN | POLLOUT;
AnnaBridge 156:ff21514d8981 222 }
AnnaBridge 156:ff21514d8981 223
AnnaBridge 171:3a7713b1edbc 224 /** Definition depends on the subclass implementing FileHandle.
AnnaBridge 156:ff21514d8981 225 * For example, if the FileHandle is of type Stream, writable() could return
AnnaBridge 156:ff21514d8981 226 * true when there is ample buffer space available for write() calls.
AnnaBridge 156:ff21514d8981 227 *
AnnaBridge 156:ff21514d8981 228 * @returns true if the FileHandle is writable.
AnnaBridge 156:ff21514d8981 229 */
AnnaBridge 156:ff21514d8981 230 bool writable() const
AnnaBridge 156:ff21514d8981 231 {
AnnaBridge 156:ff21514d8981 232 return poll(POLLOUT) & POLLOUT;
AnnaBridge 156:ff21514d8981 233 }
AnnaBridge 156:ff21514d8981 234
AnnaBridge 171:3a7713b1edbc 235 /** Definition depends on the subclass implementing FileHandle.
AnnaBridge 156:ff21514d8981 236 * For example, if the FileHandle is of type Stream, readable() could return
AnnaBridge 156:ff21514d8981 237 * true when there is something available to read.
AnnaBridge 156:ff21514d8981 238 *
AnnaBridge 156:ff21514d8981 239 * @returns true when there is something available to read.
AnnaBridge 156:ff21514d8981 240 */
AnnaBridge 156:ff21514d8981 241 bool readable() const
AnnaBridge 156:ff21514d8981 242 {
AnnaBridge 156:ff21514d8981 243 return poll(POLLIN) & POLLIN;
AnnaBridge 156:ff21514d8981 244 }
AnnaBridge 156:ff21514d8981 245
AnnaBridge 156:ff21514d8981 246 /** Register a callback on state change of the file.
AnnaBridge 156:ff21514d8981 247 *
AnnaBridge 156:ff21514d8981 248 * The specified callback will be called on state changes such as when
AnnaBridge 156:ff21514d8981 249 * the file can be written to or read from.
AnnaBridge 156:ff21514d8981 250 *
AnnaBridge 156:ff21514d8981 251 * The callback may be called in an interrupt context and should not
AnnaBridge 156:ff21514d8981 252 * perform expensive operations.
AnnaBridge 156:ff21514d8981 253 *
AnnaBridge 171:3a7713b1edbc 254 * Note! This is not intended as an attach-like asynchronous API, but rather
AnnaBridge 171:3a7713b1edbc 255 * as a building block for constructing such functionality.
AnnaBridge 156:ff21514d8981 256 *
AnnaBridge 156:ff21514d8981 257 * The exact timing of when the registered function
AnnaBridge 171:3a7713b1edbc 258 * is called is not guaranteed and is susceptible to change. It should be used
AnnaBridge 156:ff21514d8981 259 * as a cue to make read/write/poll calls to find the current state.
AnnaBridge 156:ff21514d8981 260 *
AnnaBridge 156:ff21514d8981 261 * @param func Function to call on state change
AnnaBridge 156:ff21514d8981 262 */
AnnaBridge 156:ff21514d8981 263 virtual void sigio(Callback<void()> func)
AnnaBridge 156:ff21514d8981 264 {
AnnaBridge 156:ff21514d8981 265 //Default for real files. Do nothing for real files.
AnnaBridge 156:ff21514d8981 266 }
AnnaBridge 156:ff21514d8981 267 };
AnnaBridge 156:ff21514d8981 268
AnnaBridge 158:1c57384330a6 269 /**@}*/
AnnaBridge 158:1c57384330a6 270
AnnaBridge 158:1c57384330a6 271 /**@}*/
AnnaBridge 158:1c57384330a6 272
AnnaBridge 158:1c57384330a6 273
AnnaBridge 156:ff21514d8981 274 } // namespace mbed
AnnaBridge 156:ff21514d8981 275
AnnaBridge 156:ff21514d8981 276 #endif