1/*
2 * Copyright (C) 2013 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
17package android.print;
18
19import android.annotation.NonNull;
20import android.annotation.Nullable;
21import android.content.Context;
22import android.content.pm.ParceledListSlice;
23import android.os.Handler;
24import android.os.Looper;
25import android.os.Message;
26import android.os.RemoteException;
27import android.util.ArrayMap;
28import android.util.Log;
29
30import java.lang.ref.WeakReference;
31import java.util.ArrayList;
32import java.util.Collections;
33import java.util.LinkedHashMap;
34import java.util.List;
35
36/**
37 * @hide
38 */
39public final class PrinterDiscoverySession {
40
41    private static final String LOG_TAG ="PrinterDiscoverySession";
42
43    private static final int MSG_PRINTERS_ADDED = 1;
44    private static final int MSG_PRINTERS_REMOVED = 2;
45
46    private final LinkedHashMap<PrinterId, PrinterInfo> mPrinters =
47            new LinkedHashMap<PrinterId, PrinterInfo>();
48
49    private final IPrintManager mPrintManager;
50
51    private final int mUserId;
52
53    private final Handler mHandler;
54
55    private IPrinterDiscoveryObserver mObserver;
56
57    private OnPrintersChangeListener mListener;
58
59    private boolean mIsPrinterDiscoveryStarted;
60
61    public static interface OnPrintersChangeListener {
62        public void onPrintersChanged();
63    }
64
65    PrinterDiscoverySession(IPrintManager printManager, Context context, int userId) {
66        mPrintManager = printManager;
67        mUserId = userId;
68        mHandler = new SessionHandler(context.getMainLooper());
69        mObserver = new PrinterDiscoveryObserver(this);
70        try {
71            mPrintManager.createPrinterDiscoverySession(mObserver, mUserId);
72        } catch (RemoteException re) {
73            Log.e(LOG_TAG, "Error creating printer discovery session", re);
74        }
75    }
76
77    public final void startPrinterDiscovery(@Nullable List<PrinterId> priorityList) {
78        if (isDestroyed()) {
79            Log.w(LOG_TAG, "Ignoring start printers discovery - session destroyed");
80            return;
81        }
82        if (!mIsPrinterDiscoveryStarted) {
83            mIsPrinterDiscoveryStarted = true;
84            try {
85                mPrintManager.startPrinterDiscovery(mObserver, priorityList, mUserId);
86            } catch (RemoteException re) {
87                Log.e(LOG_TAG, "Error starting printer discovery", re);
88            }
89        }
90    }
91
92    public final void stopPrinterDiscovery() {
93        if (isDestroyed()) {
94            Log.w(LOG_TAG, "Ignoring stop printers discovery - session destroyed");
95            return;
96        }
97        if (mIsPrinterDiscoveryStarted) {
98            mIsPrinterDiscoveryStarted = false;
99            try {
100                mPrintManager.stopPrinterDiscovery(mObserver, mUserId);
101            } catch (RemoteException re) {
102                Log.e(LOG_TAG, "Error stopping printer discovery", re);
103            }
104        }
105    }
106
107    public final void startPrinterStateTracking(@NonNull PrinterId printerId) {
108        if (isDestroyed()) {
109            Log.w(LOG_TAG, "Ignoring start printer state tracking - session destroyed");
110            return;
111        }
112        try {
113            mPrintManager.startPrinterStateTracking(printerId, mUserId);
114        } catch (RemoteException re) {
115            Log.e(LOG_TAG, "Error starting printer state tracking", re);
116        }
117    }
118
119    public final void stopPrinterStateTracking(@NonNull PrinterId printerId) {
120        if (isDestroyed()) {
121            Log.w(LOG_TAG, "Ignoring stop printer state tracking - session destroyed");
122            return;
123        }
124        try {
125            mPrintManager.stopPrinterStateTracking(printerId, mUserId);
126        } catch (RemoteException re) {
127            Log.e(LOG_TAG, "Error stopping printer state tracking", re);
128        }
129    }
130
131    public final void validatePrinters(List<PrinterId> printerIds) {
132        if (isDestroyed()) {
133            Log.w(LOG_TAG, "Ignoring validate printers - session destroyed");
134            return;
135        }
136        try {
137            mPrintManager.validatePrinters(printerIds, mUserId);
138        } catch (RemoteException re) {
139            Log.e(LOG_TAG, "Error validating printers", re);
140        }
141    }
142
143    public final void destroy() {
144        if (isDestroyed()) {
145            Log.w(LOG_TAG, "Ignoring destroy - session destroyed");
146        }
147        destroyNoCheck();
148    }
149
150    public final List<PrinterInfo> getPrinters() {
151        if (isDestroyed()) {
152            Log.w(LOG_TAG, "Ignoring get printers - session destroyed");
153            return Collections.emptyList();
154        }
155        return new ArrayList<PrinterInfo>(mPrinters.values());
156    }
157
158    public final boolean isDestroyed() {
159        throwIfNotCalledOnMainThread();
160        return isDestroyedNoCheck();
161    }
162
163    public final boolean isPrinterDiscoveryStarted() {
164        throwIfNotCalledOnMainThread();
165        return mIsPrinterDiscoveryStarted;
166    }
167
168    public final void setOnPrintersChangeListener(OnPrintersChangeListener listener) {
169        throwIfNotCalledOnMainThread();
170        mListener = listener;
171    }
172
173    @Override
174    protected final void finalize() throws Throwable {
175        if (!isDestroyedNoCheck()) {
176            Log.e(LOG_TAG, "Destroying leaked printer discovery session");
177            destroyNoCheck();
178        }
179        super.finalize();
180    }
181
182    private boolean isDestroyedNoCheck() {
183        return (mObserver == null);
184    }
185
186    private void destroyNoCheck() {
187        stopPrinterDiscovery();
188        try {
189            mPrintManager.destroyPrinterDiscoverySession(mObserver, mUserId);
190        } catch (RemoteException re) {
191            Log.e(LOG_TAG, "Error destroying printer discovery session", re);
192        } finally {
193            mObserver = null;
194            mPrinters.clear();
195        }
196    }
197
198    private void handlePrintersAdded(List<PrinterInfo> addedPrinters) {
199        if (isDestroyed()) {
200            return;
201        }
202
203        // No old printers - do not bother keeping their position.
204        if (mPrinters.isEmpty()) {
205            final int printerCount = addedPrinters.size();
206            for (int i = 0; i < printerCount; i++) {
207                PrinterInfo printer = addedPrinters.get(i);
208                mPrinters.put(printer.getId(), printer);
209            }
210            notifyOnPrintersChanged();
211            return;
212        }
213
214        // Add the printers to a map.
215        ArrayMap<PrinterId, PrinterInfo> addedPrintersMap =
216                new ArrayMap<PrinterId, PrinterInfo>();
217        final int printerCount = addedPrinters.size();
218        for (int i = 0; i < printerCount; i++) {
219            PrinterInfo printer = addedPrinters.get(i);
220            addedPrintersMap.put(printer.getId(), printer);
221        }
222
223        // Update printers we already have.
224        for (PrinterId oldPrinterId : mPrinters.keySet()) {
225            PrinterInfo updatedPrinter = addedPrintersMap.remove(oldPrinterId);
226            if (updatedPrinter != null) {
227                mPrinters.put(oldPrinterId, updatedPrinter);
228            }
229        }
230
231        // Add the new printers, i.e. what is left.
232        mPrinters.putAll(addedPrintersMap);
233
234        // Announce the change.
235        notifyOnPrintersChanged();
236    }
237
238    private void handlePrintersRemoved(List<PrinterId> printerIds) {
239        if (isDestroyed()) {
240            return;
241        }
242        boolean printersChanged = false;
243        final int removedPrinterIdCount = printerIds.size();
244        for (int i = 0; i < removedPrinterIdCount; i++) {
245            PrinterId removedPrinterId = printerIds.get(i);
246            if (mPrinters.remove(removedPrinterId) != null) {
247                printersChanged = true;
248            }
249        }
250        if (printersChanged) {
251            notifyOnPrintersChanged();
252        }
253    }
254
255    private void notifyOnPrintersChanged() {
256        if (mListener != null) {
257            mListener.onPrintersChanged();
258        }
259    }
260
261    private static void throwIfNotCalledOnMainThread() {
262        if (!Looper.getMainLooper().isCurrentThread()) {
263            throw new IllegalAccessError("must be called from the main thread");
264        }
265    }
266
267    private final class SessionHandler extends Handler {
268
269        public SessionHandler(Looper looper) {
270            super(looper, null, false);
271        }
272
273        @Override
274        @SuppressWarnings("unchecked")
275        public void handleMessage(Message message) {
276            switch (message.what) {
277                case MSG_PRINTERS_ADDED: {
278                    List<PrinterInfo> printers = (List<PrinterInfo>) message.obj;
279                    handlePrintersAdded(printers);
280                } break;
281
282                case MSG_PRINTERS_REMOVED: {
283                    List<PrinterId> printerIds = (List<PrinterId>) message.obj;
284                    handlePrintersRemoved(printerIds);
285                } break;
286            }
287        }
288    }
289
290    public static final class PrinterDiscoveryObserver extends IPrinterDiscoveryObserver.Stub {
291
292        private final WeakReference<PrinterDiscoverySession> mWeakSession;
293
294        public PrinterDiscoveryObserver(PrinterDiscoverySession session) {
295            mWeakSession = new WeakReference<PrinterDiscoverySession>(session);
296        }
297
298        @Override
299        @SuppressWarnings("rawtypes")
300        public void onPrintersAdded(ParceledListSlice printers) {
301            PrinterDiscoverySession session = mWeakSession.get();
302            if (session != null) {
303                session.mHandler.obtainMessage(MSG_PRINTERS_ADDED,
304                        printers.getList()).sendToTarget();
305            }
306        }
307
308        @Override
309        @SuppressWarnings("rawtypes")
310        public void onPrintersRemoved(ParceledListSlice printerIds) {
311            PrinterDiscoverySession session = mWeakSession.get();
312            if (session != null) {
313                session.mHandler.obtainMessage(MSG_PRINTERS_REMOVED,
314                        printerIds.getList()).sendToTarget();
315            }
316        }
317    }
318}
319