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
19using namespace android;
20
21// Abstraction to allow for dependency injection. See MockFileFinder.h
22// for the testing implementation.
23class FileFinder {
24public:
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
32class SystemFileFinder : public FileFinder {
33public:
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
60private:
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