DirHandle.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2013 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 #ifndef MBED_DIRHANDLE_H
00017 #define MBED_DIRHANDLE_H
00018 
00019 #include <stdint.h>
00020 #include "platform/platform.h"
00021 
00022 #include "FileHandle.h"
00023 
00024 namespace mbed {
00025 /** \addtogroup drivers */
00026 /** @{*/
00027 
00028 /** Represents a directory stream. Objects of this type are returned
00029  *  by a FileSystemLike's opendir method. Implementations must define
00030  *  at least closedir, readdir and rewinddir.
00031  *
00032  *  If a FileSystemLike class defines the opendir method, then the
00033  *  directories of an object of that type can be accessed by
00034  *  DIR *d = opendir("/example/directory") (or opendir("/example")
00035  *  to open the root of the filesystem), and then using readdir(d) etc.
00036  *
00037  *  The root directory is considered to contain all FileLike and
00038  *  FileSystemLike objects, so the DIR* returned by opendir("/") will
00039  *  reflect this.
00040  *
00041  *  @Note Synchronization level: Set by subclass
00042  */
00043 class DirHandle {
00044 public:
00045     MBED_DEPRECATED_SINCE("mbed-os-5.4",
00046         "The mbed 2 filesystem classes have been superseeded by the FileSystem api, "
00047         "Replaced by File")
00048     DirHandle() {}
00049 
00050     /** Closes the directory.
00051      *
00052      *  @returns
00053      *    0 on success,
00054      *   -1 on error.
00055      */
00056     virtual int closedir()=0;
00057 
00058     /** Return the directory entry at the current position, and
00059      *  advances the position to the next entry.
00060      *
00061      * @returns
00062      *  A pointer to a dirent structure representing the
00063      *  directory entry at the current position, or NULL on reaching
00064      *  end of directory or error.
00065      */
00066     virtual struct dirent *readdir()=0;
00067 
00068     /** Resets the position to the beginning of the directory.
00069      */
00070     virtual void rewinddir()=0;
00071 
00072     /** Returns the current position of the DirHandle.
00073      *
00074      * @returns
00075      *   the current position,
00076      *  -1 on error.
00077      */
00078     virtual off_t telldir() { return -1; }
00079 
00080     /** Sets the position of the DirHandle.
00081      *
00082      *  @param location The location to seek to. Must be a value returned by telldir.
00083      */
00084     virtual void seekdir(off_t location) { (void)location;}
00085 
00086     virtual ~DirHandle() {}
00087 
00088 protected:
00089 
00090     /** Acquire exclusive access to this object.
00091      */
00092     virtual void lock() {
00093         // Stub
00094     }
00095 
00096     /** Release exclusive access to this object.
00097      */
00098     virtual void unlock() {
00099         // Stub
00100     }
00101 
00102 protected:
00103     /** Internal-only constructor to work around deprecated notices when not used
00104      *. due to nested deprecations and difficulty of compilers finding their way around
00105      *  the class hierarchy
00106      */
00107     friend class FileSystemLike;
00108     DirHandle(int) {}
00109 };
00110 
00111 } // namespace mbed
00112 
00113 #endif /* MBED_DIRHANDLE_H */
00114 
00115 /** @}*/