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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@160:5571c4ff569f, 2018-01-17 (annotated)

Committer:
Anna Bridge
Date:
Wed Jan 17 16:13:02 2018 +0000
Revision:
160:5571c4ff569f
Parent:
158:1c57384330a6
Child:
165:d1b4690b3f8b
mbed library. Release version 158

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