1 files changed, 106 insertions, 0 deletions
diff --git a/src/com/android/camera/data/PanoramaMetadataLoader.java b/src/com/android/camera/data/PanoramaMetadataLoader.java
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+++ b/src/com/android/camera/data/PanoramaMetadataLoader.java
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+/*
+ * 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.camera.data;
+
+import android.content.Context;
+import android.net.Uri;
+
+import com.android.gallery3d.util.LightCycleHelper;
+import com.android.gallery3d.util.LightCycleHelper.PanoramaMetadata;
+
+import java.util.ArrayList;
+
+/**
+ * This class breaks out the off-thread panorama support.
+ */
+public class PanoramaMetadataLoader {
+    /**
+     * Classes implementing this interface can get information about loaded
+     * photo sphere metadata.
+     */
+    public static interface PanoramaMetadataCallback {
+        /**
+         * Called with the loaded metadata or <code>null</code>.
+         */
+        public void onPanoramaMetadataLoaded(PanoramaMetadata metadata);
+    }
+
+    private PanoramaMetadata mPanoramaMetadata;
+    private ArrayList<PanoramaMetadataCallback> mCallbacksWaiting;
+    private Uri mMediaUri;
+
+    /**
+     * Instantiated the meta data loader for the image resource with the given
+     * URI.
+     */
+    public PanoramaMetadataLoader(Uri uri) {
+        mMediaUri = uri;
+    }
+
+    /**
+     * Asynchronously extract and return panorama metadata from the item with
+     * the given URI.
+     * <p>
+     * NOTE: This call is backed by a cache to speed up successive calls, which
+     * will return immediately. Use {@link #clearCachedValues()} is called.
+     */
+    public synchronized void getPanoramaMetadata(final Context context,
+            PanoramaMetadataCallback callback) {
+        if (mPanoramaMetadata != null) {
+            // Return the cached data right away, no need to fetch it again.
+            callback.onPanoramaMetadataLoaded(mPanoramaMetadata);
+        } else {
+            if (mCallbacksWaiting == null) {
+                mCallbacksWaiting = new ArrayList<PanoramaMetadataCallback>();
+
+                // TODO: Don't create a new thread each time, use a pool or
+                // single instance.
+                (new Thread() {
+                    @Override
+                    public void run() {
+                        onLoadingDone(LightCycleHelper.getPanoramaMetadata(context,
+                                mMediaUri));
+                    }
+                }).start();
+            }
+            mCallbacksWaiting.add(callback);
+        }
+    }
+
+    /**
+     * Clear cached value and stop all running loading threads.
+     */
+    public synchronized void clearCachedValues() {
+        if (mPanoramaMetadata != null) {
+            mPanoramaMetadata = null;
+        }
+
+        // TODO: Cancel running loading thread if active.
+     }
+
+    private synchronized void onLoadingDone(PanoramaMetadata metadata) {
+        mPanoramaMetadata = metadata;
+        if (mPanoramaMetadata == null) {
+            // Error getting panorama data from file. Treat as not panorama.
+            mPanoramaMetadata = LightCycleHelper.NOT_PANORAMA;
+        }
+        for (PanoramaMetadataCallback cb : mCallbacksWaiting) {
+            cb.onPanoramaMetadataLoaded(mPanoramaMetadata);
+        }
+        mCallbacksWaiting = null;
+    }
+}