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 
~FileFinder()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(const String8& path, const struct stat* stats,
76                                 Vector<String8>& extensions,
77                                 KeyedVector<String8,time_t>& fileStore);
78 
79 };
80 #endif // FILEFINDER_H
81