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Adam Lesinski282e1812014-01-23 18:17:42 -08001//
2// Copyright 2011 The Android Open Source Project
3//
4// Cache manager for pre-processed PNG files.
5// Contains code for managing which PNG files get processed
6// at build time.
7//
8
9#ifndef CRUNCHCACHE_H
10#define CRUNCHCACHE_H
11
12#include <utils/KeyedVector.h>
13#include <utils/String8.h>
14#include "FileFinder.h"
15#include "CacheUpdater.h"
16
17using namespace android;
18
19/** CrunchCache
20 * This class is a cache manager which can pre-process PNG files and store
21 * them in a mirror-cache. It's capable of doing incremental updates to its
22 * cache.
23 *
24 * Usage:
25 * Create an instance initialized with the root of the source tree, the
26 * root location to store the cache files, and an instance of a file finder.
27 * Then update the cache by calling crunch.
28 */
29class CrunchCache {
30public:
31 // Constructor
32 CrunchCache(String8 sourcePath, String8 destPath, FileFinder* ff);
33
34 // Nobody should be calling the default constructor
35 // So this space is intentionally left blank
36
37 // Default Copy Constructor and Destructor are fine
38
39 /** crunch is the workhorse of this class.
40 * It goes through all the files found in the sourcePath and compares
41 * them to the cached versions in the destPath. If the optional
42 * argument forceOverwrite is set to true, then all source files are
43 * re-crunched even if they have not been modified recently. Otherwise,
44 * source files are only crunched when they needUpdating. Afterwards,
45 * we delete any leftover files in the cache that are no longer present
46 * in source.
47 *
48 * PRECONDITIONS:
49 * No setup besides construction is needed
50 * POSTCONDITIONS:
51 * The cache is updated to fully reflect all changes in source.
52 * The function then returns the number of files changed in cache
53 * (counting deletions).
54 */
55 size_t crunch(CacheUpdater* cu, bool forceOverwrite=false);
56
57private:
58 /** loadFiles is a wrapper to the FileFinder that places matching
59 * files into mSourceFiles and mDestFiles.
60 *
61 * POSTCONDITIONS
62 * mDestFiles and mSourceFiles are refreshed to reflect the current
63 * state of the files in the source and dest directories.
64 * Any previous contents of mSourceFiles and mDestFiles are cleared.
65 */
66 void loadFiles();
67
68 /** needsUpdating takes a file path
69 * and returns true if the file represented by this path is newer in the
70 * sourceFiles than in the cache (mDestFiles).
71 *
72 * PRECONDITIONS:
73 * mSourceFiles and mDestFiles must be initialized and filled.
74 * POSTCONDITIONS:
75 * returns true if and only if source file's modification time
76 * is greater than the cached file's mod-time. Otherwise returns false.
77 *
78 * USAGE:
79 * Should be used something like the following:
80 * if (needsUpdating(filePath))
81 * // Recrunch sourceFile out to destFile.
82 *
83 */
84 bool needsUpdating(String8 relativePath) const;
85
86 // DATA MEMBERS ====================================================
87
88 String8 mSourcePath;
89 String8 mDestPath;
90
91 Vector<String8> mExtensions;
92
93 // Each vector of paths contains one entry per PNG file encountered.
94 // Each entry consists of a path pointing to that PNG.
95 DefaultKeyedVector<String8,time_t> mSourceFiles;
96 DefaultKeyedVector<String8,time_t> mDestFiles;
97
98 // Pointer to a FileFinder to use
99 FileFinder* mFileFinder;
100};
101
102#endif // CRUNCHCACHE_H