Class to simplify use of GalleryBitmapPool for decoding Bitmaps.

 Bug 8446191
 Required for I86cfa59f448daa4e7b9fd7ea9ada2d69357e1f63

Change-Id: Ia9b2ced0bfd9c9c1b969c77bc89eaa0fa87687bb

diff --git a/src/com/android/photos/data/BitmapDecoder.java b/src/com/android/photos/data/BitmapDecoder.java
new file mode 100644 (file)
index 0000000..a0ab410
--- /dev/null
+++ b/src/com/android/photos/data/BitmapDecoder.java
@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.photos.data;
+
+import android.graphics.Bitmap;
+import android.graphics.Bitmap.Config;
+import android.graphics.BitmapFactory;
+import android.util.Log;
+import android.util.Pools.Pool;
+import android.util.Pools.SynchronizedPool;
+
+import com.android.gallery3d.common.Utils;
+
+import java.io.BufferedInputStream;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * BitmapDecoder keeps a pool of temporary storage to reuse for decoding
+ * bitmaps. It also simplifies the multi-stage decoding required to efficiently
+ * use GalleryBitmapPool. The static methods decode and decodeFile can be used
+ * to decode a bitmap from GalleryBitmapPool. The bitmap may be returned
+ * directly to GalleryBitmapPool or use the put method here when the bitmap is
+ * ready to be recycled.
+ */
+public class BitmapDecoder {
+    private static final String TAG = BitmapDecoder.class.getSimpleName();
+    private static final int POOL_SIZE = 4;
+    private static final int TEMP_STORAGE_SIZE_BYTES = 16 * 1024;
+    private static final int HEADER_MAX_SIZE = 16 * 1024;
+
+    private static final Pool<BitmapFactory.Options> sOptions =
+            new SynchronizedPool<BitmapFactory.Options>(POOL_SIZE);
+
+    public static Bitmap decode(InputStream in) {
+        BitmapFactory.Options opts = getOptions();
+        try {
+            if (!in.markSupported()) {
+                in = new BufferedInputStream(in);
+            }
+            opts.inJustDecodeBounds = true;
+            in.mark(HEADER_MAX_SIZE);
+            BitmapFactory.decodeStream(in, null, opts);
+            in.reset();
+            opts.inJustDecodeBounds = false;
+            GalleryBitmapPool pool = GalleryBitmapPool.getInstance();
+            Bitmap reuseBitmap = pool.get(opts.outWidth, opts.outHeight);
+            opts.inBitmap = reuseBitmap;
+            Bitmap decodedBitmap = BitmapFactory.decodeStream(in, null, opts);
+            if (reuseBitmap != null && decodedBitmap != reuseBitmap) {
+                pool.put(reuseBitmap);
+            }
+            return decodedBitmap;
+        } catch (IOException e) {
+            Log.e(TAG, "Could not decode stream to bitmap", e);
+            return null;
+        } finally {
+            Utils.closeSilently(in);
+            release(opts);
+        }
+    }
+
+    public static Bitmap decode(File in) {
+        return decodeFile(in.toString());
+    }
+
+    public static Bitmap decodeFile(String in) {
+        BitmapFactory.Options opts = getOptions();
+        try {
+            opts.inJustDecodeBounds = true;
+            BitmapFactory.decodeFile(in, opts);
+            opts.inJustDecodeBounds = false;
+            GalleryBitmapPool pool = GalleryBitmapPool.getInstance();
+            Bitmap reuseBitmap = pool.get(opts.outWidth, opts.outHeight);
+            opts.inBitmap = reuseBitmap;
+            Bitmap decodedBitmap = BitmapFactory.decodeFile(in, opts);
+            if (reuseBitmap != null && decodedBitmap != reuseBitmap) {
+                pool.put(reuseBitmap);
+            }
+            return decodedBitmap;
+        } finally {
+            release(opts);
+        }
+    }
+
+    public static void put(Bitmap bitmap) {
+        GalleryBitmapPool.getInstance().put(bitmap);
+    }
+
+    private static BitmapFactory.Options getOptions() {
+        BitmapFactory.Options opts = sOptions.acquire();
+        if (opts == null) {
+            opts = new BitmapFactory.Options();
+            opts.inMutable = true;
+            opts.inPreferredConfig = Config.ARGB_8888;
+            opts.inSampleSize = 1;
+            opts.inTempStorage = new byte[TEMP_STORAGE_SIZE_BYTES];
+        }
+
+        return opts;
+    }
+
+    private static void release(BitmapFactory.Options opts) {
+        opts.inBitmap = null;
+        opts.inJustDecodeBounds = false;
+        sOptions.release(opts);
+    }
+}