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
diff --git a/tools/aapt/FileFinder.cpp b/tools/aapt/FileFinder.cpp
new file mode 100644
index 0000000..a1f64d0
--- /dev/null
+++ b/tools/aapt/FileFinder.cpp
@@ -0,0 +1,92 @@
+//
+// Copyright 2011 The Android Open Source Project
+//
+
+// File Finder implementation.
+// Implementation for the functions declared and documented in FileFinder.h
+
+#include <utils/Vector.h>
+#include <utils/String8.h>
+#include <utils/KeyedVector.h>
+
+
+#include <iostream>
+
+#include "DirectoryWalker.h"
+#include "FileFinder.h"
+
+//#define DEBUG
+
+using android::String8;
+using std::cout;
+using std::endl;
+
+bool SystemFileFinder::findFiles(String8 basePath, Vector<String8>& extensions,
+                                 KeyedVector<String8,time_t>& fileStore,
+                                 DirectoryWalker* dw)
+{
+    // Scan the directory pointed to by basePath
+    // check files and recurse into subdirectories.
+    if (!dw->openDir(basePath)) {
+        return false;
+    }
+#ifdef DEBUG
+    cout << "FileFinder looking in " << basePath << endl;
+#endif // DEBUG
+    /*
+     *  Go through all directory entries. Check each file using checkAndAddFile
+     *  and recurse into sub-directories.
+     */
+    struct dirent* entry;
+    while ((entry = dw->nextEntry()) != NULL) {
+        String8 entryName(entry->d_name);
+        if (entry->d_name[0] == '.') // Skip hidden files and directories
+            continue;
+
+        String8 fullPath = basePath.appendPathCopy(entryName);
+        // If this entry is a directory we'll recurse into it
+        if (entry->d_type == DT_DIR) {
+            DirectoryWalker* copy = dw->clone();
+            findFiles(fullPath, extensions, fileStore,copy);
+            delete copy;
+        }
+
+        // If this entry is a file, we'll pass it over to checkAndAddFile
+        if (entry->d_type == DT_REG) {
+            checkAndAddFile(fullPath,dw->entryStats(),extensions,fileStore);
+        }
+    }
+
+    // Clean up
+    dw->closeDir();
+
+    return true;
+}
+
+void SystemFileFinder::checkAndAddFile(String8 path, const struct stat* stats,
+                                       Vector<String8>& extensions,
+                                       KeyedVector<String8,time_t>& fileStore)
+{
+#ifdef DEBUG
+    cout << "Checking file " << path << "...";
+#endif // DEBUG
+    // Loop over the extensions, checking for a match
+    bool done = false;
+    String8 ext(path.getPathExtension());
+    ext.toLower();
+    for (size_t i = 0; i < extensions.size() && !done; ++i) {
+        String8 ext2 = extensions[i].getPathExtension();
+        ext2.toLower();
+        // Compare the extensions. If a match is found, add to storage.
+        if (ext == ext2) {
+#ifdef DEBUG
+            cout << "Match";
+#endif // DEBUG
+            done = true;
+            fileStore.add(path,stats->st_mtime);
+        }
+    }
+#ifdef DEBUG
+    cout << endl;
+#endif //DEBUG
+}
\ No newline at end of file