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fs.h

/* ScummVM - Scumm Interpreter
 * Copyright (C) 2002-2004 The ScummVM project
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * $Header: /cvsroot/scummvm/scummvm/backends/fs/fs.h,v 1.24.2.2 2004/12/18 02:37:16 fingolfin Exp $
 */

#ifndef FS_H
#define FS_H

/*
 * The API described in this header is meant to allow for file system browsing in a
 * portable fashions. To this ends, multiple or single roots have to be supported
 * (compare Unix with a single root, Windows with multiple roots C:, D:, ...).
 *
 * To this end, we abstract away from paths; implementations can be based on
 * paths (and it's left to them whether / or \ or : is the path separator :-);
 * but it is also possible to use inodes or vrefs (MacOS 9) or anything else.
 *
 * NOTE: Backends still have to provide a way to extract a path from a FSIntern
 *
 * You may ask now: "isn't this cheating? Why do we go through all this when we use
 * a path in the end anyway?!?".
 * Well, for once as long as we don't provide our own file open/read/write API, we
 * still have to use fopen(). Since all our targets already support fopen(), it should
 * be possible to get a fopen() compatible string for any file system node.
 *
 * Secondly, with this abstraction layer, we still avoid a lot of complications based on
 * differences in FS roots, different path separators, or even systems with no real
 * paths (MacOS 9 doesn't even have the notion of a "current directory").
 * And if we ever want to support devices with no FS in the classical sense (Palm...),
 * we can build upon this.
 */
 
/* 
 * TODO - Instead of starting with getRoot(), we should rather add a getDefaultDir()
 * call that on Unix might return the current dir or the users home dir...
 * i.e. the root dir is usually not the best starting point for browsing.
 */

#include "common/array.h"
#include "common/str.h"

class FilesystemNode;


/**
 * List of multiple file system nodes. E.g. the contents of a given directory.
 */
00063 class FSList : public Common::Array<FilesystemNode> {
public:
      void sort();
};


/**
 * File system node.
 */
00072 class AbstractFilesystemNode {
protected:
      friend class FilesystemNode;
      typedef Common::String String;

      /**
       * The parent node of this directory.
       * The parent of the root is the root itself.
       */
      virtual AbstractFilesystemNode *parent() const = 0;

      /**
       * This method is a rather ugly hack which is used internally by the 
       * actual node implementions to wrap up raw nodes inside FilesystemNode
       * objects. We probably want to get rid of this eventually and replace it
       * with a cleaner / more elegant solution, but for now it works.
       * @note This takes over ownership of node. Do not delete it yourself,
       *       else you'll get ugly crashes. You've been warned!
       */
      static FilesystemNode wrap(AbstractFilesystemNode *node);

public:

      /**
       * Flag to tell listDir() which kind of files to list.
       */
00098       typedef enum {
            kListFilesOnly = 1,
            kListDirectoriesOnly = 2,
            kListAll = 3
      } ListMode;

      virtual ~AbstractFilesystemNode() {}

      /**
       * Return display name, used by e.g. the GUI to present the file in the file browser.
       * @return the display name
       */
      virtual String displayName() const = 0;

      /**
       * Is this node valid (i.e. referring to an actual FS object)?
       */
      virtual bool isValid() const = 0;

      /**
       * Is this node a directory or not?
       */
      virtual bool isDirectory() const = 0;

      /**
       * A path representation suitable for use with fopen()
       */
      virtual String path() const = 0;

      /**
       * List the content of this directory node.
       * If this node is not a directory, throw an exception or call error().
       */
      virtual FSList listDir(ListMode mode = kListDirectoriesOnly) const = 0;

      /**
       * Compare the name of this node to the name of another.
       */
00136       virtual bool operator< (const AbstractFilesystemNode& node) const
      {
            return scumm_stricmp(displayName().c_str(), node.displayName().c_str()) < 0;
      }


      /* TODO:
      bool exists();

      bool isDirectory();
      bool isFile();

      bool isReadable();
      bool isWriteable();
      */
};

class FilesystemNode : public AbstractFilesystemNode {
      friend class AbstractFilesystemNode;

      typedef Common::String String;
private:
      AbstractFilesystemNode *_realNode;
      int *_refCount;

      /**
       * Returns a special node representing the FS root. The starting point for
       * any file system browsing.
       * On Unix, this will be simply the node for / (the root directory).
       * On Windows, it will be a special node which "contains" all drives (C:, D:, E:).
       */
      static AbstractFilesystemNode *getRoot();

#ifdef MACOSX
      /*
       * Construct a node based on a path; the path is in the same format as it
       * would be for calls to fopen().
       *
       * I.e. getNodeForPath(oldNode.path()) should create a new node identical to oldNode.
       */
      static AbstractFilesystemNode *getNodeForPath(const String &path);
#endif


public:
      FilesystemNode();
      FilesystemNode(const FilesystemNode &node);
#ifdef MACOSX
      FilesystemNode(const String &path);
#endif
      ~FilesystemNode();

      FilesystemNode &operator  =(const FilesystemNode &node);

      FilesystemNode getParent() const;


      virtual String displayName() const { return _realNode->displayName(); }
      virtual bool isValid() const { return _realNode->isValid(); }
      virtual bool isDirectory() const { return _realNode->isDirectory(); }
      virtual String path() const { return _realNode->path(); }

      virtual FSList listDir(ListMode mode = kListDirectoriesOnly) const { return _realNode->listDir(mode); }

protected:
      void decRefCount();

      virtual AbstractFilesystemNode *parent() const { return 0; }
};


#endif

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