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fs.h

/* ScummVM - Scumm Interpreter
 * Copyright (C) 2002-2006 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * $URL: https://svn.sourceforge.net/svnroot/scummvm/scummvm/tags/release-0-9-1/backends/fs/fs.h $
 * $Id: fs.h 22424 2006-05-12 21:41:54Z fingolfin $
 */

#ifndef BACKENDS_FS_H
#define BACKENDS_FS_H

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

class FilesystemNode;
class AbstractFilesystemNode;


/**
 * List of multiple file system nodes. E.g. the contents of a given directory.
 * This is subclass instead of just a typedef so that we can use forward
 * declarations of it in other places.
 */
00037 class FSList : public Common::Array<FilesystemNode> {};


/*
 * FilesystemNode provides an abstraction for file pathes, allowing for portable
 * file system browsing. 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.
 */
class FilesystemNode {
      typedef Common::String String;
private:
      AbstractFilesystemNode *_realNode;
      int *_refCount;

      FilesystemNode(AbstractFilesystemNode *realNode);

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

      /**
       * Create a new invalid FilesystemNode. In other words, isValid() for that
       * node returns false, and if you try to get it's path, an assert is
       * triggered.
       */
      FilesystemNode();

      /**
       * Create a new FilesystemNode referring to the specified path. This is
       * the counterpart to the path() method.
       *
       * If path is empty or equals ".", then a node representing the "current
       * directory" will be created. If that is not possible (since e.g. the
       * operating system doesn't support the concept), some other directory is
       * used (usually the root directory).
       */
      FilesystemNode(const String &path);

      /**
       * Copy constructor.
       */
      FilesystemNode(const FilesystemNode &node);
      
      /**
       * Destructor.
       */
      virtual ~FilesystemNode();

      /**
       * Copy operator.
       */
      FilesystemNode &operator  =(const FilesystemNode &node);

      /**
       * Get the parent node of this node. If this node has no parent node,
       * then it returns a duplicate of this node.
       */
      FilesystemNode getParent() const;

      /**
       * Fetch a child node of this node, with the given name. Only valid for
       * directory nodes (an assertion is triggered otherwise). If no no child
       * node with the given name exists, an invalid node is returned.
       */
      FilesystemNode getChild(const String &name) const;

      /**
       * Return a list of child nodes of this directory node. If called on a node
       * that does not represent a directory, false is returned.
       * @return true if succesful, false otherwise (e.g. when the directory does not exist).
       * @todo Rename this to listChildren or getChildren.
       */
      virtual bool listDir(FSList &fslist, ListMode mode = kListDirectoriesOnly) const;

      /**
       * Return a human readable string for this node, usable for display (e.g.
       * in the GUI code). Do *not* rely on it being usable for anything else,
       * like constructing paths!
       * @return the display name
       */
      virtual String displayName() const;

      /**
       * Is this node pointing to a directory?
       * @todo Currently we assume that a valid node that is not a directory
       * automatically is a file (ignoring things like symlinks). That might
       * actually be OK... but we could still add an isFile method. Or even replace
       * isValid and isDirectory by a getType() method that can return values like
       * kDirNodeType, kFileNodeType, kInvalidNodeType.
       */
      virtual bool isDirectory() const;

      /**
       * Return a string representation of the file which can be passed to fopen(),
       * and is suitable for archiving (i.e. writing to the config file).
       * This will usually be a 'path' (hence the name of the method), but can
       * be anything that fulfilly the above criterions.
       */
      virtual String path() const;

      /**
       * Compare the name of this node to the name of another. Directories
       * go before normal files.
       */
      bool operator< (const FilesystemNode& node) const;

protected:
      void decRefCount();
};


#endif

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