CrunchCache.cpp

   1 //
   2 // Copyright 2011 The Android Open Source Project
   3 //
   4 // Implementation file for CrunchCache
   5 // This file defines functions laid out and documented in
   6 // CrunchCache.h
   7
   8 #include <utils/Vector.h>
   9 #include <utils/String8.h>
  10
  11 #include "DirectoryWalker.h"
  12 #include "FileFinder.h"
  13 #include "CacheUpdater.h"
  14 #include "CrunchCache.h"
  15
  16 using namespace android;
  17
  18 CrunchCache::CrunchCache(String8 sourcePath, String8 destPath, FileFinder* ff)
  19     : mSourcePath(sourcePath), mDestPath(destPath), mSourceFiles(0), mDestFiles(0), mFileFinder(ff)
  20 {
  21     // We initialize the default value to return to 0 so if a file doesn't exist
  22     // then all files are automatically "newer" than it.
  23
  24     // Set file extensions to look for. Right now just pngs.
  25     mExtensions.push(String8(".png"));
  26
  27     // Load files into our data members
  28     loadFiles();
  29 }
  30
  31 size_t CrunchCache::crunch(CacheUpdater* cu, bool forceOverwrite)
  32 {
  33     size_t numFilesUpdated = 0;
  34
  35     // Iterate through the source files and compare to cache.
  36     // After processing a file, remove it from the source files and
  37     // from the dest files.
  38     // We're done when we're out of files in source.
  39     String8 relativePath;
  40     while (mSourceFiles.size() > 0) {
  41         // Get the full path to the source file, then convert to a c-string
  42         // and offset our beginning pointer to the length of the sourcePath
  43         // This efficiently strips the source directory prefix from our path.
  44         // Also, String8 doesn't have a substring method so this is what we've
  45         // got to work with.
  46         const char* rPathPtr = mSourceFiles.keyAt(0).string()+mSourcePath.length();
  47         // Strip leading slash if present
  48         int offset = 0;
  49         if (rPathPtr[0] == OS_PATH_SEPARATOR)
  50             offset = 1;
  51         relativePath = String8(rPathPtr + offset);
  52
  53         if (forceOverwrite || needsUpdating(relativePath)) {
  54             cu->processImage(mSourcePath.appendPathCopy(relativePath),
  55                              mDestPath.appendPathCopy(relativePath));
  56             numFilesUpdated++;
  57             // crunchFile(relativePath);
  58         }
  59         // Delete this file from the source files and (if it exists) from the
  60         // dest files.
  61         mSourceFiles.removeItemsAt(0);
  62         mDestFiles.removeItem(mDestPath.appendPathCopy(relativePath));
  63     }
  64
  65     // Iterate through what's left of destFiles and delete leftovers
  66     while (mDestFiles.size() > 0) {
  67         cu->deleteFile(mDestFiles.keyAt(0));
  68         mDestFiles.removeItemsAt(0);
  69     }
  70
  71     // Update our knowledge of the files cache
  72     // both source and dest should be empty by now.
  73     loadFiles();
  74
  75     return numFilesUpdated;
  76 }
  77
  78 void CrunchCache::loadFiles()
  79 {
  80     // Clear out our data structures to avoid putting in duplicates
  81     mSourceFiles.clear();
  82     mDestFiles.clear();
  83
  84     // Make a directory walker that points to the system.
  85     DirectoryWalker* dw = new SystemDirectoryWalker();
  86
  87     // Load files in the source directory
  88     mFileFinder->findFiles(mSourcePath, mExtensions, mSourceFiles,dw);
  89
  90     // Load files in the destination directory
  91     mFileFinder->findFiles(mDestPath,mExtensions,mDestFiles,dw);
  92
  93     delete dw;
  94 }
  95
  96 bool CrunchCache::needsUpdating(String8 relativePath) const
  97 {
  98     // Retrieve modification dates for this file entry under the source and
  99     // cache directory trees. The vectors will return a modification date of 0
 100     // if the file doesn't exist.
 101     time_t sourceDate = mSourceFiles.valueFor(mSourcePath.appendPathCopy(relativePath));
 102     time_t destDate = mDestFiles.valueFor(mDestPath.appendPathCopy(relativePath));
 103     return sourceDate > destDate;
 104 }