aboutsummaryrefslogtreecommitdiff
path: root/common/fs.h
blob: e6f2fe18fe862d7b6bc1791b2af4e9044a4ce671 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * 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.
 *
 */

#ifndef COMMON_FS_H
#define COMMON_FS_H

#include "common/array.h"
#include "common/archive.h"
#include "common/hash-str.h"
#include "common/hashmap.h"
#include "common/ptr.h"
#include "common/str.h"

class AbstractFSNode;

namespace Common {

class FSNode;
class SeekableReadStream;
class WriteStream;

/**
 * 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.
 */
class FSList : public Array<FSNode> {};

/**
 * FSNode, short for "File System Node", provides an abstraction for file
 * paths, allowing for portable file system browsing. This means for example,
 * that 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.
 */
class FSNode : public ArchiveMember {
private:
	SharedPtr<AbstractFSNode>	_realNode;

public:
    FSNode(AbstractFSNode *realNode);

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

	/**
	 * Create a new pathless FSNode. Since there's no path associated
	 * with this node, path-related operations (i.e. exists(), isDirectory(),
	 * getPath()) will always return false or raise an assertion.
	 */
	FSNode();

	/**
	 * Create a new FSNode 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).
	 */
	explicit FSNode(const String &path);

	virtual ~FSNode() {}

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

	/**
	 * Indicates whether the object referred by this node exists in the filesystem or not.
	 *
	 * @return bool true if the node exists, false otherwise.
	 */
	bool exists() const;

	/**
	 * Create a new node referring to a child node of the current node, which
	 * must be a directory node (otherwise an invalid node is returned).
	 * If a child matching the name exists, a normal node for it is returned.
	 * If no child with the name exists, a node for it is still returned,
	 * but exists() will return 'false' for it. This node can however be used
	 * to create a new file using the createWriteStream() method.
	 *
	 * @todo If createWriteStream() (or a hypothetical future mkdir() method) is used,
	 *       this should affect what exists/isDirectory/isReadable/isWritable return
	 *       for existing nodes. However, this is not the case for many existing
	 *       FSNode implementations. Either fix those, or document that FSNodes
	 *       can become 'stale'...
	 *
	 * @param name	the name of a child of this directory
	 * @return the node referring to the child with the given name
	 */
	FSNode getChild(const String &name) const;

	/**
	 * Return a list of all child nodes of this directory node. If called on a node
	 * that does not represent a directory, false is returned.
	 *
	 * @return true if successful, false otherwise (e.g. when the directory does not exist).
	 */
	bool getChildren(FSList &fslist, ListMode mode = kListDirectoriesOnly, bool hidden = false) 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 getDisplayName() const;

	/**
	 * Return a string representation of the name of the file. This can be
	 * used e.g. by detection code that relies on matching the name of a given
	 * file. But it is *not* suitable for use with fopen / File::open, nor
	 * should it be archived.
	 *
	 * @return the file name
	 */
	virtual String getName() const;

	/**
	 * Return a string representation of the file which 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 meets
	 * the above criterions. What a 'path' is differs greatly from system to
	 * system anyway.
	 *
	 * @note Do not assume that this string contains (back)slashes or any
	 *       other kind of 'path separators'.
	 *
	 * @return the 'path' represented by this filesystem node
	 */
	String getPath() const;

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

	/**
	 * Indicates whether the node refers to a directory or not.
	 *
	 * @todo Currently we assume that a node that is not a directory
	 * automatically is a file (ignoring things like symlinks or pipes).
	 * That might actually be OK... but we could still add an isFile method.
	 * Or even replace isDirectory by a getType() method that can return values like
	 * kDirNodeType, kFileNodeType, kInvalidNodeType.
	 */
	bool isDirectory() const;

	/**
	 * Indicates whether the object referred by this node can be read from or not.
	 *
	 * If the node refers to a directory, readability implies being able to read
	 * and list the directory entries.
	 *
	 * If the node refers to a file, readability implies being able to read the
	 * contents of the file.
	 *
	 * @return true if the object can be read, false otherwise.
	 */
	bool isReadable() const;

	/**
	 * Indicates whether the object referred by this node can be written to or not.
	 *
	 * If the node refers to a directory, writability implies being able to modify
	 * the directory entry (i.e. rename the directory, remove it or write files inside of it).
	 *
	 * If the node refers to a file, writability implies being able to write data
	 * to the file.
	 *
	 * @return true if the object can be written to, false otherwise.
	 */
	bool isWritable() const;

	/**
	 * Creates a SeekableReadStream instance corresponding to the file
	 * referred by this node. This assumes that the node actually refers
	 * to a readable file. If this is not the case, 0 is returned.
	 *
	 * @return pointer to the stream object, 0 in case of a failure
	 */
	virtual SeekableReadStream *createReadStream() const;

	/**
	 * Creates a WriteStream instance corresponding to the file
	 * referred by this node. This assumes that the node actually refers
	 * to a readable file. If this is not the case, 0 is returned.
	 *
	 * @return pointer to the stream object, 0 in case of a failure
	 */
	WriteStream *createWriteStream() const;
};

/**
 * FSDirectory models a directory tree from the filesystem and allows users
 * to access it through the Archive interface. Searching is case-insensitive,
 * since the intended goal is supporting retrieval of game data.
 *
 * FSDirectory can represent a single directory, or a tree with specified depth,
 * depending on the value passed to the 'depth' parameter in the constructors.
 * In the default mode, filenames are cached with their relative path,
 * with elements separated by slashes, e.g.:
 *
 * c:\my\data\file.ext
 *
 * would be cached as 'data/file.ext' if FSDirectory was created on 'c:/my' with
 * depth > 1. If depth was 1, then the 'data' subdirectory would have been
 * ignored, instead.
 * Again, only SLASHES are used as separators independently from the
 * underlying file system.
 *
 * Relative paths can be specified when calling matching functions like createReadStreamForMember(),
 * hasFile(), listMatchingMembers() and listMembers(). Please see the function
 * specific comments for more information.
 *
 * If the 'flat' argument to the constructor is true, files in subdirectories
 * are cached without the relative path, so in the example above
 * c:\my\data\file.ext would be cached as file.ext.
 *
 * Client code can customize cache by using the constructors with the 'prefix'
 * parameter. In this case, the prefix is prepended to each entry in the cache,
 * and effectively treated as a 'virtual' parent subdirectory. FSDirectory adds
 * a trailing slash to prefix if needed. Following on with the previous example
 * and using 'your' as prefix, the cache entry would have been 'your/data/file.ext'.
 * This is done both in non-flat and flat mode.
 *
 */
class FSDirectory : public Archive {
	FSNode	_node;

	String	_prefix;	// string that is prepended to each cache item key
	void setPrefix(const String &prefix);

	// Caches are case insensitive, clashes are dealt with when creating
	// Key is stored in lowercase.
	typedef HashMap<String, FSNode, IgnoreCase_Hash, IgnoreCase_EqualTo> NodeCache;
	mutable NodeCache	_fileCache, _subDirCache;
	mutable bool _cached;
	mutable int	_depth;
	mutable bool _flat;

	// look for a match
	FSNode *lookupCache(NodeCache &cache, const String &name) const;

	// cache management
	void cacheDirectoryRecursive(FSNode node, int depth, const String& prefix) const;

	// fill cache if not already cached
	void ensureCached() const;

public:
	/**
	 * Create a FSDirectory representing a tree with the specified depth. Will result in an
	 * unbound FSDirectory if name is not found on the filesystem or if the node is not a
	 * valid directory.
	 */
	FSDirectory(const String &name, int depth = 1, bool flat = false);
	FSDirectory(const FSNode &node, int depth = 1, bool flat = false);

	/**
	 * Create a FSDirectory representing a tree with the specified depth. The parameter
	 * prefix is prepended to the keys in the cache. See class comment.
	 */
	FSDirectory(const String &prefix, const String &name, int depth = 1,
	            bool flat = false);
	FSDirectory(const String &prefix, const FSNode &node, int depth = 1,
	            bool flat = false);

	virtual ~FSDirectory();

	/**
	 * This return the underlying FSNode of the FSDirectory.
	 */
	FSNode getFSNode() const;

	/**
	 * Create a new FSDirectory pointing to a sub directory of the instance. See class comment
	 * for an explanation of the prefix parameter.
	 * @return a new FSDirectory instance
	 */
	FSDirectory *getSubDirectory(const String &name, int depth = 1, bool flat = false);
	FSDirectory *getSubDirectory(const String &prefix, const String &name, int depth = 1, bool flat = false);

	/**
	 * Checks for existence in the cache. A full match of relative path and filename is needed
	 * for success.
	 */
	virtual bool hasFile(const String &name) const;

	/**
	 * Returns a list of matching file names. Pattern can use GLOB wildcards.
	 */
	virtual int listMatchingMembers(ArchiveMemberList &list, const String &pattern) const;

	/**
	 * Returns a list of all the files in the cache.
	 */
	virtual int listMembers(ArchiveMemberList &list) const;

	/**
	 * Get a ArchiveMember representation of the specified file. A full match of relative
	 * path and filename is needed for success.
	 */
	virtual const ArchiveMemberPtr getMember(const String &name) const;

	/**
	 * Open the specified file. A full match of relative path and filename is needed
	 * for success.
	 */
	virtual SeekableReadStream *createReadStreamForMember(const String &name) const;
};


} // End of namespace Common

#endif //COMMON_FS_H