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      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
     81