Added Caching for PreProcessed PNGs

Added a cache management system for pre-processed PNG files
along with unit tests. The cache system will be used if
the --no-crunch flag is passed to AAPT during the package
phase. The cache can be updated by a call to 'aapt crunch'
(see usage statement). Also put in benchmarking code.

Change-Id: I58271fb2ee2f5f9075fd74d4ff6f15e7afabd05c

1 files changed, 78 insertions, 0 deletions

diff --git a/tools/aapt/FileFinder.h b/tools/aapt/FileFinder.h
new file mode 100644
index 000000000000..3f87aba0a084
--- /dev/null
+++ b/tools/aapt/FileFinder.h
@@ -0,0 +1,78 @@
+//
+// Copyright 2011 The Android Open Source Project
+//
+
+// File Finder.
+// This is a collection of useful functions for finding paths and modification
+// times of files that match an extension pattern in a directory tree.
+// and finding files in it.
+
+#ifndef FILEFINDER_H
+#define FILEFINDER_H
+
+#include <utils/Vector.h>
+#include <utils/KeyedVector.h>
+#include <utils/String8.h>
+
+#include "DirectoryWalker.h"
+
+using namespace android;
+
+// Abstraction to allow for dependency injection. See MockFileFinder.h
+// for the testing implementation.
+class FileFinder {
+public:
+    virtual bool findFiles(String8 basePath, Vector<String8>& extensions,
+                           KeyedVector<String8,time_t>& fileStore,
+                           DirectoryWalker* dw) = 0;
+};
+
+class SystemFileFinder : public FileFinder {
+public:
+
+    /* findFiles takes a path, a Vector of extensions, and a destination KeyedVector
+     *           and places path/modification date key/values pointing to
+     *          all files with matching extensions found into the KeyedVector
+     * PRECONDITIONS
+     *     path is a valid system path
+     *     extensions should include leading "."
+     *                This is not necessary, but the comparison directly
+     *                compares the end of the path string so if the "."
+     *                is excluded there is a small chance you could have
+     *                a false positive match. (For example: extension "png"
+     *                would match a file called "blahblahpng")
+     *
+     * POSTCONDITIONS
+     *     fileStore contains (in no guaranteed order) paths to all
+     *                matching files encountered in subdirectories of path
+     *                as keys in the KeyedVector. Each key has the modification time
+     *                of the file as its value.
+     *
+     * Calls checkAndAddFile on each file encountered in the directory tree
+     * Recursively descends into subdirectories.
+     */
+    virtual bool findFiles(String8 basePath, Vector<String8>& extensions,
+                           KeyedVector<String8,time_t>& fileStore,
+                           DirectoryWalker* dw);
+
+private:
+    /**
+     * checkAndAddFile looks at a single file path and stat combo
+     * to determine whether it is a matching file (by looking at
+     * the extension)
+     *
+     * PRECONDITIONS
+     *    no setup is needed
+     *
+     * POSTCONDITIONS
+     *    If the given file has a matching extension then a new entry
+     *    is added to the KeyedVector with the path as the key and the modification
+     *    time as the value.
+     *
+     */
+    static void checkAndAddFile(String8 path, const struct stat* stats,
+                                Vector<String8>& extensions,
+                                KeyedVector<String8,time_t>& fileStore);
+
+};
+#endif // FILEFINDER_H