Owen Lin | 666ea1b | 2009-10-14 22:34:47 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2009 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package com.android.camera; |
| 18 | |
Owen Lin | 8aa3fbc | 2009-10-22 20:24:04 -0700 | [diff] [blame] | 19 | import android.content.ContentResolver; |
Owen Lin | 666ea1b | 2009-10-14 22:34:47 -0700 | [diff] [blame] | 20 | import android.graphics.Bitmap; |
| 21 | import android.graphics.BitmapFactory; |
Owen Lin | 8aa3fbc | 2009-10-22 20:24:04 -0700 | [diff] [blame] | 22 | import android.provider.MediaStore.Images; |
| 23 | import android.provider.MediaStore.Video; |
Owen Lin | 666ea1b | 2009-10-14 22:34:47 -0700 | [diff] [blame] | 24 | import android.util.Log; |
| 25 | |
| 26 | import java.io.FileDescriptor; |
| 27 | import java.util.WeakHashMap; |
| 28 | |
| 29 | /** |
| 30 | * This class provides several utilities to cancel bitmap decoding. |
| 31 | * |
| 32 | * The function decodeFileDescriptor() is used to decode a bitmap. During |
| 33 | * decoding if another thread wants to cancel it, it calls the function |
| 34 | * cancelThreadDecoding() specifying the Thread which is in decoding. |
| 35 | * |
| 36 | * cancelThreadDecoding() is sticky until allowThreadDecoding() is called. |
| 37 | */ |
| 38 | public class BitmapManager { |
| 39 | private static final String TAG = "BitmapManager"; |
| 40 | private static enum State {CANCEL, ALLOW} |
| 41 | private static class ThreadStatus { |
| 42 | public State mState = State.ALLOW; |
| 43 | public BitmapFactory.Options mOptions; |
Owen Lin | 8aa3fbc | 2009-10-22 20:24:04 -0700 | [diff] [blame] | 44 | public boolean mThumbRequesting; |
Owen Lin | 666ea1b | 2009-10-14 22:34:47 -0700 | [diff] [blame] | 45 | @Override |
| 46 | public String toString() { |
| 47 | String s; |
| 48 | if (mState == State.CANCEL) { |
| 49 | s = "Cancel"; |
| 50 | } else if (mState == State.ALLOW) { |
| 51 | s = "Allow"; |
| 52 | } else { |
| 53 | s = "?"; |
| 54 | } |
| 55 | s = "thread state = " + s + ", options = " + mOptions; |
| 56 | return s; |
| 57 | } |
| 58 | } |
| 59 | |
| 60 | private final WeakHashMap<Thread, ThreadStatus> mThreadStatus = |
| 61 | new WeakHashMap<Thread, ThreadStatus>(); |
| 62 | |
| 63 | private static BitmapManager sManager = null; |
| 64 | |
| 65 | private BitmapManager() { |
| 66 | } |
| 67 | |
| 68 | /** |
| 69 | * Get thread status and create one if specified. |
| 70 | */ |
| 71 | private synchronized ThreadStatus getOrCreateThreadStatus(Thread t) { |
| 72 | ThreadStatus status = mThreadStatus.get(t); |
| 73 | if (status == null) { |
| 74 | status = new ThreadStatus(); |
| 75 | mThreadStatus.put(t, status); |
| 76 | } |
| 77 | return status; |
| 78 | } |
| 79 | |
| 80 | /** |
| 81 | * The following three methods are used to keep track of |
| 82 | * BitmapFaction.Options used for decoding and cancelling. |
| 83 | */ |
| 84 | private synchronized void setDecodingOptions(Thread t, |
| 85 | BitmapFactory.Options options) { |
| 86 | getOrCreateThreadStatus(t).mOptions = options; |
| 87 | } |
| 88 | |
| 89 | synchronized void removeDecodingOptions(Thread t) { |
| 90 | ThreadStatus status = mThreadStatus.get(t); |
| 91 | status.mOptions = null; |
| 92 | } |
| 93 | |
| 94 | /** |
| 95 | * The following three methods are used to keep track of which thread |
| 96 | * is being disabled for bitmap decoding. |
| 97 | */ |
| 98 | public synchronized boolean canThreadDecoding(Thread t) { |
| 99 | ThreadStatus status = mThreadStatus.get(t); |
| 100 | if (status == null) { |
| 101 | // allow decoding by default |
| 102 | return true; |
| 103 | } |
| 104 | |
| 105 | boolean result = (status.mState != State.CANCEL); |
| 106 | return result; |
| 107 | } |
| 108 | |
| 109 | public synchronized void allowThreadDecoding(Thread t) { |
| 110 | getOrCreateThreadStatus(t).mState = State.ALLOW; |
| 111 | } |
| 112 | |
Owen Lin | 8aa3fbc | 2009-10-22 20:24:04 -0700 | [diff] [blame] | 113 | public synchronized void cancelThreadDecoding(Thread t, ContentResolver cr) { |
Owen Lin | 666ea1b | 2009-10-14 22:34:47 -0700 | [diff] [blame] | 114 | ThreadStatus status = getOrCreateThreadStatus(t); |
| 115 | status.mState = State.CANCEL; |
| 116 | if (status.mOptions != null) { |
| 117 | status.mOptions.requestCancelDecode(); |
| 118 | } |
| 119 | |
| 120 | // Wake up threads in waiting list |
| 121 | notifyAll(); |
Owen Lin | 8aa3fbc | 2009-10-22 20:24:04 -0700 | [diff] [blame] | 122 | |
| 123 | // Since our cancel request can arrive MediaProvider earlier than getThumbnail request, |
| 124 | // we use mThumbRequesting flag to make sure our request does cancel the request. |
| 125 | try { |
| 126 | synchronized (status) { |
| 127 | while (status.mThumbRequesting) { |
| 128 | Images.Thumbnails.cancelThumbnailRequest(cr, -1, t.getId()); |
| 129 | Video.Thumbnails.cancelThumbnailRequest(cr, -1, t.getId()); |
| 130 | status.wait(200); |
| 131 | } |
| 132 | } |
| 133 | } catch (InterruptedException ex) { |
| 134 | // ignore it. |
| 135 | } |
| 136 | } |
| 137 | |
| 138 | public Bitmap getThumbnail(ContentResolver cr, long origId, int kind, |
| 139 | BitmapFactory.Options options, boolean isVideo) { |
| 140 | Thread t = Thread.currentThread(); |
| 141 | ThreadStatus status = getOrCreateThreadStatus(t); |
| 142 | |
| 143 | if (!canThreadDecoding(t)) { |
| 144 | Log.d(TAG, "Thread " + t + " is not allowed to decode."); |
| 145 | return null; |
| 146 | } |
| 147 | |
| 148 | try { |
| 149 | synchronized (status) { |
| 150 | status.mThumbRequesting = true; |
| 151 | } |
| 152 | if (isVideo) { |
| 153 | return Video.Thumbnails.getThumbnail(cr, origId, t.getId(), |
| 154 | kind, null); |
| 155 | } else { |
| 156 | return Images.Thumbnails.getThumbnail(cr, origId, t.getId(), |
| 157 | kind, null); |
| 158 | } |
| 159 | } finally { |
| 160 | synchronized (status) { |
| 161 | status.mThumbRequesting = false; |
| 162 | status.notifyAll(); |
| 163 | } |
| 164 | } |
Owen Lin | 666ea1b | 2009-10-14 22:34:47 -0700 | [diff] [blame] | 165 | } |
| 166 | |
| 167 | public static synchronized BitmapManager instance() { |
| 168 | if (sManager == null) { |
| 169 | sManager = new BitmapManager(); |
| 170 | } |
| 171 | return sManager; |
| 172 | } |
| 173 | |
| 174 | /** |
| 175 | * The real place to delegate bitmap decoding to BitmapFactory. |
| 176 | */ |
| 177 | public Bitmap decodeFileDescriptor(FileDescriptor fd, |
| 178 | BitmapFactory.Options options) { |
| 179 | if (options.mCancel) { |
| 180 | return null; |
| 181 | } |
| 182 | |
| 183 | Thread thread = Thread.currentThread(); |
| 184 | if (!canThreadDecoding(thread)) { |
| 185 | Log.d(TAG, "Thread " + thread + " is not allowed to decode."); |
| 186 | return null; |
| 187 | } |
| 188 | |
| 189 | setDecodingOptions(thread, options); |
| 190 | Bitmap b = BitmapFactory.decodeFileDescriptor(fd, null, options); |
| 191 | |
| 192 | removeDecodingOptions(thread); |
| 193 | return b; |
| 194 | } |
| 195 | } |