/* mbed Microcontroller Library
 * Copyright (c) 2006-2013 ARM Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef MBED_DIRHANDLE_H
#define MBED_DIRHANDLE_H

#include <stdint.h>
#include "platform/platform.h"

#include "FileHandle.h"

namespace mbed {
/** \addtogroup drivers */
/** @{*/

/** Represents a directory stream. Objects of this type are returned
 *  by a FileSystemLike's opendir method. Implementations must define
 *  at least closedir, readdir and rewinddir.
 *
 *  If a FileSystemLike class defines the opendir method, then the
 *  directories of an object of that type can be accessed by
 *  DIR *d = opendir("/example/directory") (or opendir("/example")
 *  to open the root of the filesystem), and then using readdir(d) etc.
 *
 *  The root directory is considered to contain all FileLike and
 *  FileSystemLike objects, so the DIR* returned by opendir("/") will
 *  reflect this.
 *
 *  @Note Synchronization level: Set by subclass
 */
class DirHandle {
public:
    MBED_DEPRECATED_SINCE("mbed-os-5.4",
        "The mbed 2 filesystem classes have been superseeded by the FileSystem api, "
        "Replaced by File")
    DirHandle() {}

    /** Closes the directory.
     *
     *  @returns
     *    0 on success,
     *   -1 on error.
     */
    virtual int closedir()=0;

    /** Return the directory entry at the current position, and
     *  advances the position to the next entry.
     *
     * @returns
     *  A pointer to a dirent structure representing the
     *  directory entry at the current position, or NULL on reaching
     *  end of directory or error.
     */
    virtual struct dirent *readdir()=0;

    /** Resets the position to the beginning of the directory.
     */
    virtual void rewinddir()=0;

    /** Returns the current position of the DirHandle.
     *
     * @returns
     *   the current position,
     *  -1 on error.
     */
    virtual off_t telldir() { return -1; }

    /** Sets the position of the DirHandle.
     *
     *  @param location The location to seek to. Must be a value returned by telldir.
     */
    virtual void seekdir(off_t location) { (void)location;}

    virtual ~DirHandle() {}

protected:

    /** Acquire exclusive access to this object.
     */
    virtual void lock() {
        // Stub
    }

    /** Release exclusive access to this object.
     */
    virtual void unlock() {
        // Stub
    }

protected:
    /** Internal-only constructor to work around deprecated notices when not used
     *. due to nested deprecations and difficulty of compilers finding their way around
     *  the class hierarchy
     */
    friend class FileSystemLike;
    DirHandle(int) {}
};

} // namespace mbed

#endif /* MBED_DIRHANDLE_H */

/** @}*/
