1 files changed, 187 insertions, 0 deletions
diff --git a/src/com/android/gallery3d/app/SlideshowDataAdapter.java b/src/com/android/gallery3d/app/SlideshowDataAdapter.java
new file mode 100644
index 000000000..6f9b98e8e
--- /dev/null
+++ b/src/com/android/gallery3d/app/SlideshowDataAdapter.java
@@ -0,0 +1,187 @@
+/*
+ * Copyright (C) 2010 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.gallery3d.app;
+
+import com.android.gallery3d.app.SlideshowPage.Slide;
+import com.android.gallery3d.data.ContentListener;
+import com.android.gallery3d.data.MediaItem;
+import com.android.gallery3d.data.MediaObject;
+import com.android.gallery3d.util.Future;
+import com.android.gallery3d.util.FutureListener;
+import com.android.gallery3d.util.ThreadPool;
+import com.android.gallery3d.util.ThreadPool.Job;
+import com.android.gallery3d.util.ThreadPool.JobContext;
+
+import android.graphics.Bitmap;
+
+import java.util.LinkedList;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+public class SlideshowDataAdapter implements SlideshowPage.Model {
+    @SuppressWarnings("unused")
+    private static final String TAG = "SlideshowDataAdapter";
+
+    private static final int IMAGE_QUEUE_CAPACITY = 3;
+
+    public interface SlideshowSource {
+        public void addContentListener(ContentListener listener);
+        public void removeContentListener(ContentListener listener);
+        public long reload();
+        public MediaItem getMediaItem(int index);
+    }
+
+    private final SlideshowSource mSource;
+
+    private int mLoadIndex = 0;
+    private int mNextOutput = 0;
+    private boolean mIsActive = false;
+    private boolean mNeedReset;
+    private boolean mDataReady;
+
+    private final LinkedList<Slide> mImageQueue = new LinkedList<Slide>();
+
+    private Future<Void> mReloadTask;
+    private final ThreadPool mThreadPool;
+
+    private long mDataVersion = MediaObject.INVALID_DATA_VERSION;
+    private final AtomicBoolean mNeedReload = new AtomicBoolean(false);
+    private final SourceListener mSourceListener = new SourceListener();
+
+    public SlideshowDataAdapter(GalleryContext context, SlideshowSource source, int index) {
+        mSource = source;
+        mLoadIndex = index;
+        mNextOutput = index;
+        mThreadPool = context.getThreadPool();
+    }
+
+    public MediaItem loadItem() {
+        if (mNeedReload.compareAndSet(true, false)) {
+            long v = mSource.reload();
+            if (v != mDataVersion) {
+                mDataVersion = v;
+                mNeedReset = true;
+                return null;
+            }
+        }
+        return mSource.getMediaItem(mLoadIndex);
+    }
+
+    private class ReloadTask implements Job<Void> {
+        public Void run(JobContext jc) {
+            while (true) {
+                synchronized (SlideshowDataAdapter.this) {
+                    while (mIsActive && (!mDataReady
+                            || mImageQueue.size() >= IMAGE_QUEUE_CAPACITY)) {
+                        try {
+                            SlideshowDataAdapter.this.wait();
+                        } catch (InterruptedException ex) {
+                            // ignored.
+                        }
+                        continue;
+                    }
+                }
+                if (!mIsActive) return null;
+                mNeedReset = false;
+
+                MediaItem item = loadItem();
+
+                if (mNeedReset) {
+                    synchronized (SlideshowDataAdapter.this) {
+                        mImageQueue.clear();
+                        mLoadIndex = mNextOutput;
+                    }
+                    continue;
+                }
+
+                if (item == null) {
+                    synchronized (SlideshowDataAdapter.this) {
+                        if (!mNeedReload.get()) mDataReady = false;
+                        SlideshowDataAdapter.this.notifyAll();
+                    }
+                    continue;
+                }
+
+                Bitmap bitmap = item
+                        .requestImage(MediaItem.TYPE_THUMBNAIL)
+                        .run(jc);
+
+                if (bitmap != null) {
+                    synchronized (SlideshowDataAdapter.this) {
+                        mImageQueue.addLast(
+                                new Slide(item, mLoadIndex, bitmap));
+                        if (mImageQueue.size() == 1) {
+                            SlideshowDataAdapter.this.notifyAll();
+                        }
+                    }
+                }
+                ++mLoadIndex;
+            }
+        }
+    }
+
+    private class SourceListener implements ContentListener {
+        public void onContentDirty() {
+            synchronized (SlideshowDataAdapter.this) {
+                mNeedReload.set(true);
+                mDataReady = true;
+                SlideshowDataAdapter.this.notifyAll();
+            }
+        }
+    }
+
+    private synchronized Slide innerNextBitmap() {
+        while (mIsActive && mDataReady && mImageQueue.isEmpty()) {
+            try {
+                wait();
+            } catch (InterruptedException t) {
+                throw new AssertionError();
+            }
+        }
+        if (mImageQueue.isEmpty()) return null;
+        mNextOutput++;
+        this.notifyAll();
+        return mImageQueue.removeFirst();
+    }
+
+    public Future<Slide> nextSlide(FutureListener<Slide> listener) {
+        return mThreadPool.submit(new Job<Slide>() {
+            public Slide run(JobContext jc) {
+                jc.setMode(ThreadPool.MODE_NONE);
+                return innerNextBitmap();
+            }
+        }, listener);
+    }
+
+    public void pause() {
+        synchronized (this) {
+            mIsActive = false;
+            notifyAll();
+        }
+        mSource.removeContentListener(mSourceListener);
+        mReloadTask.cancel();
+        mReloadTask.waitDone();
+        mReloadTask = null;
+    }
+
+    public synchronized void resume() {
+        mIsActive = true;
+        mSource.addContentListener(mSourceListener);
+        mNeedReload.set(true);
+        mDataReady = true;
+        mReloadTask = mThreadPool.submit(new ReloadTask());
+    }
+}