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/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.gecko;
import org.mozilla.gecko.db.BrowserDB;
import org.mozilla.gecko.gfx.BitmapUtils;
import org.mozilla.gecko.gfx.IntSize;
import org.mozilla.gecko.mozglue.DirectBufferAllocator;
import android.graphics.Bitmap;
import android.util.Log;
import java.nio.ByteBuffer;
import java.util.LinkedList;
import java.util.concurrent.atomic.AtomicInteger;
/**
* Helper class to generate thumbnails for tabs.
* Internally, a queue of pending thumbnails is maintained in mPendingThumbnails.
* The head of the queue is the thumbnail that is currently being processed; upon
* completion of the current thumbnail the next one is automatically processed.
* Changes to the thumbnail width are stashed in mPendingWidth and the change is
* applied between thumbnail processing. This allows a single thumbnail buffer to
* be used for all thumbnails.
*/
public final class ThumbnailHelper {
private static final String LOGTAG = "GeckoThumbnailHelper";
public static final float THUMBNAIL_ASPECT_RATIO = 0.714f; // this is a 5:7 ratio (as per UX decision)
// static singleton stuff
private static ThumbnailHelper sInstance;
public static synchronized ThumbnailHelper getInstance() {
if (sInstance == null) {
sInstance = new ThumbnailHelper();
}
return sInstance;
}
// instance stuff
private final LinkedList<Tab> mPendingThumbnails; // synchronized access only
private AtomicInteger mPendingWidth;
private int mWidth;
private int mHeight;
private ByteBuffer mBuffer;
private ThumbnailHelper() {
mPendingThumbnails = new LinkedList<Tab>();
mPendingWidth = new AtomicInteger((int)GeckoAppShell.getContext().getResources().getDimension(R.dimen.tab_thumbnail_width));
mWidth = -1;
mHeight = -1;
}
public void getAndProcessThumbnailFor(Tab tab) {
if ("about:home".equals(tab.getURL())) {
tab.updateThumbnail(null);
return;
}
if (tab.getState() == Tab.STATE_DELAYED) {
String url = tab.getURL();
if (url != null) {
byte[] thumbnail = BrowserDB.getThumbnailForUrl(GeckoAppShell.getContext().getContentResolver(), url);
if (thumbnail != null) {
setTabThumbnail(tab, null, thumbnail);
}
}
return;
}
synchronized (mPendingThumbnails) {
if (mPendingThumbnails.lastIndexOf(tab) > 0) {
// This tab is already in the queue, so don't add it again.
// Note that if this tab is only at the *head* of the queue,
// (i.e. mPendingThumbnails.lastIndexOf(tab) == 0) then we do
// add it again because it may have already been thumbnailed
// and now we need to do it again.
return;
}
mPendingThumbnails.add(tab);
if (mPendingThumbnails.size() > 1) {
// Some thumbnail was already being processed, so wait
// for that to be done.
return;
}
}
requestThumbnailFor(tab);
}
public void setThumbnailWidth(int width) {
mPendingWidth.set(IntSize.nextPowerOfTwo(width));
}
private void updateThumbnailSize() {
// Apply any pending width updates
mWidth = mPendingWidth.get();
mWidth &= ~0x1; // Ensure the width is always an even number (bug 776906)
mHeight = Math.round(mWidth * THUMBNAIL_ASPECT_RATIO);
int capacity = mWidth * mHeight * 2; // Multiply by 2 for 16bpp
if (mBuffer == null || mBuffer.capacity() != capacity) {
if (mBuffer != null) {
mBuffer = DirectBufferAllocator.free(mBuffer);
}
try {
mBuffer = DirectBufferAllocator.allocate(capacity);
} catch (IllegalArgumentException iae) {
Log.w(LOGTAG, iae.toString());
} catch (OutOfMemoryError oom) {
Log.w(LOGTAG, "Unable to allocate thumbnail buffer of capacity " + capacity);
}
// If we hit an error above, mBuffer will be pointing to null, so we are in a sane state.
}
}
private void requestThumbnailFor(Tab tab) {
updateThumbnailSize();
if (mBuffer == null) {
// Buffer allocation may have failed. In this case we can't send the
// event requesting the screenshot which means we won't get back a response
// and so our queue will grow unboundedly. Handle this scenario by clearing
// the queue (no point trying more thumbnailing right now since we're likely
// low on memory). We will try again normally on the next call to
// getAndProcessThumbnailFor which will hopefully be when we have more free memory.
synchronized (mPendingThumbnails) {
mPendingThumbnails.clear();
}
return;
}
GeckoEvent e = GeckoEvent.createThumbnailEvent(tab.getId(), mWidth, mHeight, mBuffer);
GeckoAppShell.sendEventToGecko(e);
}
/* This method is invoked by JNI once the thumbnail data is ready. */
public static void notifyThumbnail(ByteBuffer data, int tabId, boolean success) {
Tab tab = Tabs.getInstance().getTab(tabId);
ThumbnailHelper helper = ThumbnailHelper.getInstance();
if (success && tab != null) {
helper.handleThumbnailData(tab, data);
}
helper.processNextThumbnail(tab);
}
private void processNextThumbnail(Tab tab) {
Tab nextTab = null;
synchronized (mPendingThumbnails) {
if (tab != null && tab != mPendingThumbnails.peek()) {
Log.e(LOGTAG, "handleThumbnailData called with unexpected tab's data!");
// This should never happen, but recover gracefully by processing the
// unexpected tab that we found in the queue
} else {
mPendingThumbnails.remove();
}
nextTab = mPendingThumbnails.peek();
}
if (nextTab != null) {
requestThumbnailFor(nextTab);
}
}
private void handleThumbnailData(Tab tab, ByteBuffer data) {
if (data != mBuffer) {
// This should never happen, but log it and recover gracefully
Log.e(LOGTAG, "handleThumbnailData called with an unexpected ByteBuffer!");
}
if (shouldUpdateThumbnail(tab)) {
processThumbnailData(tab, data);
}
}
private void processThumbnailData(Tab tab, ByteBuffer data) {
Bitmap b = tab.getThumbnailBitmap(mWidth, mHeight);
data.position(0);
b.copyPixelsFromBuffer(data);
setTabThumbnail(tab, b, null);
}
private void setTabThumbnail(Tab tab, Bitmap bitmap, byte[] compressed) {
if (bitmap == null) {
if (compressed == null) {
Log.w(LOGTAG, "setTabThumbnail: one of bitmap or compressed must be non-null!");
return;
}
bitmap = BitmapUtils.decodeByteArray(compressed);
}
tab.updateThumbnail(bitmap);
}
private boolean shouldUpdateThumbnail(Tab tab) {
return (Tabs.getInstance().isSelectedTab(tab) || (GeckoAppShell.getGeckoInterface() != null && GeckoAppShell.getGeckoInterface().areTabsShown()));
}
}
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