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The official Mbed 2 C/C++ SDK provides the software platform and libraries to build your applications.

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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@157:e7ca05fa8600, 2017-11-09 (annotated)

Committer:
AnnaBridge
Date:
Thu Nov 09 11:14:10 2017 +0000
Revision:
157:e7ca05fa8600
Parent:
156:ff21514d8981
Child:
158:1c57384330a6
Release 155 of the mbed library.

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