FileSystemLike.cpp

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 #include "drivers/FileSystemLike.h"
00017 
00018 namespace mbed {
00019 
00020 class BaseDirHandle : public DirHandle {
00021 public:
00022     /*
00023       We keep track of our current location as the n'th object in the
00024       FileSystemLike list. Using a Base* instead would cause problems if that
00025       object were to be destroyed between readdirs.
00026       Using this method does mean though that destroying/creating objects can
00027       give unusual results from readdir.
00028     */
00029     off_t n;
00030     struct dirent cur_entry;
00031 
00032     BaseDirHandle() : DirHandle(0), n(0), cur_entry() {
00033     }
00034 
00035     virtual int closedir() {
00036         // No lock can be used in destructor
00037         delete this;
00038         return 0;
00039     }
00040 
00041     virtual struct dirent *readdir() {
00042         lock();
00043         FileBase *ptr = FileBase::get(n);
00044         if (ptr == NULL) {
00045             unlock();
00046             return NULL;
00047         }
00048 
00049         /* Increment n, so next readdir gets the next item */
00050         n++;
00051 
00052         /* Setup cur entry and return a pointer to it */
00053         std::strncpy(cur_entry.d_name, ptr->getName(), NAME_MAX);
00054         unlock();
00055         return &cur_entry;
00056     }
00057 
00058     virtual off_t telldir() {
00059         lock();
00060         off_t offset = n;
00061         unlock();
00062         return offset;
00063     }
00064 
00065     virtual void seekdir(off_t offset) {
00066         lock();
00067         n = offset;
00068         unlock();
00069     }
00070 
00071     virtual void rewinddir() {
00072         lock();
00073         n = 0;
00074         unlock();
00075     }
00076 
00077 protected:
00078     PlatformMutex _mutex;
00079 
00080     virtual void lock() {
00081         _mutex.lock();
00082     }
00083 
00084     virtual void unlock() {
00085         _mutex.unlock();
00086     }
00087 };
00088 
00089 FileSystemLike::FileSystemLike(const char *name) : FileBase(name, FileSystemPathType) {
00090 
00091 }
00092 
00093 FileSystemLike::~FileSystemLike() {
00094 
00095 }
00096 
00097 DirHandle *FileSystemLike::opendir() {
00098     return new BaseDirHandle();
00099 }
00100 
00101 } // namespace mbed