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, 107 insertions, 0 deletions

diff --git a/tools/aapt/CacheUpdater.h b/tools/aapt/CacheUpdater.h
new file mode 100644
index 0000000..0e65589
--- /dev/null
+++ b/tools/aapt/CacheUpdater.h
@@ -0,0 +1,107 @@
+//
+// Copyright 2011 The Android Open Source Project
+//
+// Abstraction of calls to system to make directories and delete files and
+// wrapper to image processing.
+
+#ifndef CACHE_UPDATER_H
+#define CACHE_UPDATER_H
+
+#include <utils/String8.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdio.h>
+#include "Images.h"
+
+using namespace android;
+
+/** CacheUpdater
+ *  This is a pure virtual class that declares abstractions of functions useful
+ *  for managing a cache files. This manager is set up to be used in a
+ *  mirror cache where the source tree is duplicated and filled with processed
+ *  images. This class is abstracted to allow for dependency injection during
+ *  unit testing.
+ *  Usage:
+ *      To update/add a file to the cache, call processImage
+ *      To remove a file from the cache, call deleteFile
+ */
+class CacheUpdater {
+public:
+    // Make sure all the directories along this path exist
+    virtual void ensureDirectoriesExist(String8 path) = 0;
+
+    // Delete a file
+    virtual void deleteFile(String8 path) = 0;
+
+    // Process an image from source out to dest
+    virtual void processImage(String8 source, String8 dest) = 0;
+private:
+};
+
+/** SystemCacheUpdater
+ * This is an implementation of the above virtual cache updater specification.
+ * This implementations hits the filesystem to manage a cache and calls out to
+ * the PNG crunching in images.h to process images out to its cache components.
+ */
+class SystemCacheUpdater : public CacheUpdater {
+public:
+    // Constructor to set bundle to pass to preProcessImage
+    SystemCacheUpdater (Bundle* b)
+        : bundle(b) { };
+
+    // Make sure all the directories along this path exist
+    virtual void ensureDirectoriesExist(String8 path)
+    {
+        // Check to see if we're dealing with a fully qualified path
+        String8 existsPath;
+        String8 toCreate;
+        String8 remains;
+        struct stat s;
+
+        // Check optomistically to see if all directories exist.
+        // If something in the path doesn't exist, then walk the path backwards
+        // and find the place to start creating directories forward.
+        if (stat(path.string(),&s) == -1) {
+            // Walk backwards to find place to start creating directories
+            existsPath = path;
+            do {
+                // As we remove the end of existsPath add it to
+                // the string of paths to create.
+                toCreate = existsPath.getPathLeaf().appendPath(toCreate);
+                existsPath = existsPath.getPathDir();
+            } while (stat(existsPath.string(),&s) == -1);
+
+            // Walk forwards and build directories as we go
+            do {
+                // Advance to the next segment of the path
+                existsPath.appendPath(toCreate.walkPath(&remains));
+                toCreate = remains;
+#ifdef HAVE_MS_C_RUNTIME
+                _mkdir(existsPath.string());
+#else
+                mkdir(existsPath.string(), S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IXGRP);
+#endif
+            } while (remains.length() > 0);
+        } //if
+    };
+
+    // Delete a file
+    virtual void deleteFile(String8 path)
+    {
+        if (remove(path.string()) != 0)
+            fprintf(stderr,"ERROR DELETING %s\n",path.string());
+    };
+
+    // Process an image from source out to dest
+    virtual void processImage(String8 source, String8 dest)
+    {
+        // Make sure we're trying to write to a directory that is extant
+        ensureDirectoriesExist(dest.getPathDir());
+
+        preProcessImageToCache(bundle, source, dest);
+    };
+private:
+    Bundle* bundle;
+};
+
+#endif // CACHE_UPDATER_H
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