1 // 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 17 using 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 */ 29 class CrunchCache { 30 public: 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 57 private: 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 103