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 #if defined(__ARMCC_VERSION) || defined(__ICCARM__)
00020 #   define NAME_MAX 255
00021 typedef int mode_t;
00022 
00023 #else
00024 #   include <sys/syslimits.h>
00025 #endif
00026 
00027 #include "FileHandle.h"
00028 
00029 struct dirent {
00030     char d_name[NAME_MAX+1];
00031 };
00032 
00033 namespace mbed {
00034 /** \addtogroup drivers */
00035 /** @{*/
00036 
00037 /** Represents a directory stream. Objects of this type are returned
00038  *  by a FileSystemLike's opendir method. Implementations must define
00039  *  at least closedir, readdir and rewinddir.
00040  *
00041  *  If a FileSystemLike class defines the opendir method, then the
00042  *  directories of an object of that type can be accessed by
00043  *  DIR *d = opendir("/example/directory") (or opendir("/example")
00044  *  to open the root of the filesystem), and then using readdir(d) etc.
00045  *
00046  *  The root directory is considered to contain all FileLike and
00047  *  FileSystemLike objects, so the DIR* returned by opendir("/") will
00048  *  reflect this.
00049  *
00050  *  @Note Synchronization level: Set by subclass
00051  */
00052 class DirHandle {
00053 
00054 public:
00055     /** Closes the directory.
00056      *
00057      *  @returns
00058      *    0 on success,
00059      *   -1 on error.
00060      */
00061     virtual int closedir()=0;
00062 
00063     /** Return the directory entry at the current position, and
00064      *  advances the position to the next entry.
00065      *
00066      * @returns
00067      *  A pointer to a dirent structure representing the
00068      *  directory entry at the current position, or NULL on reaching
00069      *  end of directory or error.
00070      */
00071     virtual struct dirent *readdir()=0;
00072 
00073     /** Resets the position to the beginning of the directory.
00074      */
00075     virtual void rewinddir()=0;
00076 
00077     /** Returns the current position of the DirHandle.
00078      *
00079      * @returns
00080      *   the current position,
00081      *  -1 on error.
00082      */
00083     virtual off_t telldir() { return -1; }
00084 
00085     /** Sets the position of the DirHandle.
00086      *
00087      *  @param location The location to seek to. Must be a value returned by telldir.
00088      */
00089     virtual void seekdir(off_t location) { (void)location;}
00090 
00091     virtual ~DirHandle() {}
00092 
00093 protected:
00094 
00095     /** Acquire exclusive access to this object.
00096      */
00097     virtual void lock() {
00098         // Stub
00099     }
00100 
00101     /** Release exclusive access to this object.
00102      */
00103     virtual void unlock() {
00104         // Stub
00105     }
00106 };
00107 
00108 } // namespace mbed
00109 
00110 typedef mbed::DirHandle DIR;
00111 
00112 extern "C" {
00113     DIR *opendir(const char*);
00114     struct dirent *readdir(DIR *);
00115     int closedir(DIR*);
00116     void rewinddir(DIR*);
00117     long telldir(DIR*);
00118     void seekdir(DIR*, long);
00119     int mkdir(const char *name, mode_t n);
00120 };
00121 
00122 #endif /* MBED_DIRHANDLE_H */
00123 
00124 /** @}*/