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.hardware.camera2.utils;
18
19import static android.hardware.camera2.CameraAccessException.CAMERA_DISABLED;
20import static android.hardware.camera2.CameraAccessException.CAMERA_DISCONNECTED;
21import static android.hardware.camera2.CameraAccessException.CAMERA_IN_USE;
22import static android.hardware.camera2.CameraAccessException.CAMERA_ERROR;
23import static android.hardware.camera2.CameraAccessException.MAX_CAMERAS_IN_USE;
24import static android.hardware.camera2.CameraAccessException.CAMERA_DEPRECATED_HAL;
25
26import android.os.DeadObjectException;
27import android.os.RemoteException;
28
29import java.lang.reflect.Method;
30
31/**
32 * Translate camera device status_t return values into exceptions.
33 *
34 * @see android.hardware.camera2.utils.CameraBinderDecorator#newInstance
35 * @hide
36 */
37public class CameraBinderDecorator {
38
39    public static final int NO_ERROR = 0;
40    public static final int PERMISSION_DENIED = -1;
41    public static final int ALREADY_EXISTS = -17;
42    public static final int BAD_VALUE = -22;
43    public static final int DEAD_OBJECT = -32;
44    public static final int INVALID_OPERATION = -38;
45    public static final int TIMED_OUT = -110;
46
47    /**
48     * TODO: add as error codes in Errors.h
49     * - POLICY_PROHIBITS
50     * - RESOURCE_BUSY
51     * - NO_SUCH_DEVICE
52     * - NOT_SUPPORTED
53     * - TOO_MANY_USERS
54     */
55    public static final int EACCES = -13;
56    public static final int EBUSY = -16;
57    public static final int ENODEV = -19;
58    public static final int EOPNOTSUPP = -95;
59    public static final int EUSERS = -87;
60
61
62    static class CameraBinderDecoratorListener implements Decorator.DecoratorListener {
63
64        @Override
65        public void onBeforeInvocation(Method m, Object[] args) {
66        }
67
68        @Override
69        public void onAfterInvocation(Method m, Object[] args, Object result) {
70            // int return type => status_t => convert to exception
71            if (m.getReturnType() == Integer.TYPE) {
72                int returnValue = (Integer) result;
73                throwOnError(returnValue);
74            }
75        }
76
77        @Override
78        public boolean onCatchException(Method m, Object[] args, Throwable t) {
79
80            if (t instanceof DeadObjectException) {
81                throw new CameraRuntimeException(CAMERA_DISCONNECTED,
82                        "Process hosting the camera service has died unexpectedly",
83                        t);
84            } else if (t instanceof RemoteException) {
85                throw new UnsupportedOperationException("An unknown RemoteException was thrown" +
86                        " which should never happen.", t);
87            }
88
89            return false;
90        }
91
92        @Override
93        public void onFinally(Method m, Object[] args) {
94        }
95
96    }
97
98    /**
99     * Throw error codes returned by the camera service as exceptions.
100     *
101     * @param errorFlag error to throw as an exception.
102     */
103    public static void throwOnError(int errorFlag) {
104        switch (errorFlag) {
105            case NO_ERROR:
106                return;
107            case PERMISSION_DENIED:
108                throw new SecurityException("Lacking privileges to access camera service");
109            case ALREADY_EXISTS:
110                // This should be handled at the call site. Typically this isn't bad,
111                // just means we tried to do an operation that already completed.
112                return;
113            case BAD_VALUE:
114                throw new IllegalArgumentException("Bad argument passed to camera service");
115            case DEAD_OBJECT:
116                throw new CameraRuntimeException(CAMERA_DISCONNECTED);
117            case TIMED_OUT:
118                throw new CameraRuntimeException(CAMERA_ERROR,
119                        "Operation timed out in camera service");
120            case EACCES:
121                throw new CameraRuntimeException(CAMERA_DISABLED);
122            case EBUSY:
123                throw new CameraRuntimeException(CAMERA_IN_USE);
124            case EUSERS:
125                throw new CameraRuntimeException(MAX_CAMERAS_IN_USE);
126            case ENODEV:
127                throw new CameraRuntimeException(CAMERA_DISCONNECTED);
128            case EOPNOTSUPP:
129                throw new CameraRuntimeException(CAMERA_DEPRECATED_HAL);
130            case INVALID_OPERATION:
131                throw new CameraRuntimeException(CAMERA_ERROR,
132                        "Illegal state encountered in camera service.");
133        }
134
135        /**
136         * Trap the rest of the negative return values. If we have known
137         * error codes i.e. ALREADY_EXISTS that aren't really runtime
138         * errors, then add them to the top switch statement
139         */
140        if (errorFlag < 0) {
141            throw new UnsupportedOperationException(String.format("Unknown error %d",
142                    errorFlag));
143        }
144    }
145
146    /**
147     * <p>
148     * Wraps the type T with a proxy that will check 'status_t' return codes
149     * from the native side of the camera service, and throw Java exceptions
150     * automatically based on the code.
151     * </p>
152     * <p>
153     * In addition it also rewrites binder's RemoteException into either a
154     * CameraAccessException or an UnsupportedOperationException.
155     * </p>
156     * <p>
157     * As a result of calling any method on the proxy, RemoteException is
158     * guaranteed never to be thrown.
159     * </p>
160     *
161     * @param obj object that will serve as the target for all method calls
162     * @param <T> the type of the element you want to wrap. This must be an interface.
163     * @return a proxy that will intercept all invocations to obj
164     */
165    public static <T> T newInstance(T obj) {
166        return Decorator.<T> newInstance(obj, new CameraBinderDecoratorListener());
167    }
168}
169