FileFinder.h

   1 //
   2 // Copyright 2011 The Android Open Source Project
   3 //
   4
   5 // File Finder.
   6 // This is a collection of useful functions for finding paths and modification
   7 // times of files that match an extension pattern in a directory tree.
   8 // and finding files in it.
   9
  10 #ifndef FILEFINDER_H
  11 #define FILEFINDER_H
  12
  13 #include <utils/Vector.h>
  14 #include <utils/KeyedVector.h>
  15 #include <utils/String8.h>
  16
  17 #include "DirectoryWalker.h"
  18
  19 using namespace android;
  20
  21 // Abstraction to allow for dependency injection. See MockFileFinder.h
  22 // for the testing implementation.
  23 class FileFinder {
  24 public:
  25     virtual bool findFiles(String8 basePath, Vector<String8>& extensions,
  26                            KeyedVector<String8,time_t>& fileStore,
  27                            DirectoryWalker* dw) = 0;
  28
  29     virtual ~FileFinder() {};
  30 };
  31
  32 class SystemFileFinder : public FileFinder {
  33 public:
  34
  35     /* findFiles takes a path, a Vector of extensions, and a destination KeyedVector
  36      *           and places path/modification date key/values pointing to
  37      *          all files with matching extensions found into the KeyedVector
  38      * PRECONDITIONS
  39      *     path is a valid system path
  40      *     extensions should include leading "."
  41      *                This is not necessary, but the comparison directly
  42      *                compares the end of the path string so if the "."
  43      *                is excluded there is a small chance you could have
  44      *                a false positive match. (For example: extension "png"
  45      *                would match a file called "blahblahpng")
  46      *
  47      * POSTCONDITIONS
  48      *     fileStore contains (in no guaranteed order) paths to all
  49      *                matching files encountered in subdirectories of path
  50      *                as keys in the KeyedVector. Each key has the modification time
  51      *                of the file as its value.
  52      *
  53      * Calls checkAndAddFile on each file encountered in the directory tree
  54      * Recursively descends into subdirectories.
  55      */
  56     virtual bool findFiles(String8 basePath, Vector<String8>& extensions,
  57                            KeyedVector<String8,time_t>& fileStore,
  58                            DirectoryWalker* dw);
  59
  60 private:
  61     /**
  62      * checkAndAddFile looks at a single file path and stat combo
  63      * to determine whether it is a matching file (by looking at
  64      * the extension)
  65      *
  66      * PRECONDITIONS
  67      *    no setup is needed
  68      *
  69      * POSTCONDITIONS
  70      *    If the given file has a matching extension then a new entry
  71      *    is added to the KeyedVector with the path as the key and the modification
  72      *    time as the value.
  73      *
  74      */
  75     static void checkAndAddFile(String8 path, const struct stat* stats,
  76                                 Vector<String8>& extensions,
  77                                 KeyedVector<String8,time_t>& fileStore);
  78
  79 };
  80 #endif // FILEFINDER_H