Igor Murashkin | e363fbb | 2013-06-25 20:26:06 +0000 | [diff] [blame] | 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 | |
| 17 | package android.hardware.photography.utils; |
| 18 | |
| 19 | import static android.hardware.photography.CameraAccessException.CAMERA_DISABLED; |
| 20 | import static android.hardware.photography.CameraAccessException.CAMERA_DISCONNECTED; |
| 21 | import static android.hardware.photography.CameraAccessException.CAMERA_IN_USE; |
| 22 | |
| 23 | import android.os.DeadObjectException; |
| 24 | import android.os.RemoteException; |
| 25 | |
| 26 | import java.lang.reflect.Method; |
| 27 | |
| 28 | /** |
| 29 | * Translate camera service status_t return values into exceptions. |
| 30 | * |
| 31 | * @see android.hardware.photography.utils.CameraBinderDecorator#newInstance |
| 32 | * @hide |
| 33 | */ |
| 34 | public class CameraBinderDecorator { |
| 35 | |
| 36 | public static final int NO_ERROR = 0; |
| 37 | public static final int PERMISSION_DENIED = -1; |
| 38 | public static final int ALREADY_EXISTS = -17; |
| 39 | public static final int BAD_VALUE = -22; |
| 40 | public static final int DEAD_OBJECT = -32; |
| 41 | |
| 42 | /** |
| 43 | * TODO: add as error codes in Errors.h |
| 44 | * - POLICY_PROHIBITS |
| 45 | * - RESOURCE_BUSY |
| 46 | * - NO_SUCH_DEVICE |
| 47 | */ |
| 48 | public static final int EACCES = -13; |
| 49 | public static final int EBUSY = -16; |
| 50 | public static final int ENODEV = -19; |
| 51 | |
| 52 | private static class CameraBinderDecoratorListener implements Decorator.DecoratorListener { |
| 53 | |
| 54 | @Override |
| 55 | public void onBeforeInvocation(Method m, Object[] args) { |
| 56 | } |
| 57 | |
| 58 | @Override |
| 59 | public void onAfterInvocation(Method m, Object[] args, Object result) { |
| 60 | // int return type => status_t => convert to exception |
| 61 | if (m.getReturnType() == Integer.TYPE) { |
| 62 | int returnValue = (Integer) result; |
| 63 | |
| 64 | switch (returnValue) { |
| 65 | case NO_ERROR: |
| 66 | return; |
| 67 | case PERMISSION_DENIED: |
| 68 | throw new SecurityException("Lacking privileges to access camera service"); |
| 69 | case ALREADY_EXISTS: |
Igor Murashkin | 7072550 | 2013-06-25 20:27:06 +0000 | [diff] [blame^] | 70 | // This should be handled at the call site. Typically this isn't bad, |
| 71 | // just means we tried to do an operation that already completed. |
Igor Murashkin | e363fbb | 2013-06-25 20:26:06 +0000 | [diff] [blame] | 72 | return; |
| 73 | case BAD_VALUE: |
| 74 | throw new IllegalArgumentException("Bad argument passed to camera service"); |
| 75 | case DEAD_OBJECT: |
| 76 | UncheckedThrow.throwAnyException(new CameraRuntimeException( |
| 77 | CAMERA_DISCONNECTED)); |
| 78 | // TODO: Camera service (native side) should return |
| 79 | // EACCES error |
| 80 | // when there's a policy manager disabled causing this |
| 81 | case EACCES: |
| 82 | UncheckedThrow.throwAnyException(new CameraRuntimeException( |
| 83 | CAMERA_DISABLED)); |
| 84 | case EBUSY: |
| 85 | UncheckedThrow.throwAnyException(new CameraRuntimeException( |
| 86 | CAMERA_IN_USE)); |
| 87 | case ENODEV: |
| 88 | UncheckedThrow.throwAnyException(new CameraRuntimeException( |
| 89 | CAMERA_DISCONNECTED)); |
| 90 | } |
| 91 | |
| 92 | /** |
| 93 | * Trap the rest of the negative return values. If we have known |
| 94 | * error codes i.e. ALREADY_EXISTS that aren't really runtime |
| 95 | * errors, then add them to the top switch statement |
| 96 | */ |
| 97 | if (returnValue < 0) { |
| 98 | throw new UnsupportedOperationException(String.format("Unknown error %d", |
| 99 | returnValue)); |
| 100 | } |
| 101 | } |
| 102 | } |
| 103 | |
| 104 | @Override |
| 105 | public boolean onCatchException(Method m, Object[] args, Throwable t) { |
| 106 | |
| 107 | if (t instanceof DeadObjectException) { |
| 108 | UncheckedThrow.throwAnyException(new CameraRuntimeException( |
| 109 | CAMERA_DISCONNECTED, |
| 110 | "Process hosting the camera service has died unexpectedly", |
| 111 | t)); |
| 112 | } else if (t instanceof RemoteException) { |
| 113 | throw new UnsupportedOperationException("An unknown RemoteException was thrown" + |
| 114 | " which should never happen.", t); |
| 115 | } |
| 116 | |
| 117 | return false; |
| 118 | } |
| 119 | |
| 120 | @Override |
| 121 | public void onFinally(Method m, Object[] args) { |
| 122 | } |
| 123 | |
| 124 | } |
| 125 | |
| 126 | /** |
| 127 | * <p> |
| 128 | * Wraps the type T with a proxy that will check 'status_t' return codes |
| 129 | * from the native side of the camera service, and throw Java exceptions |
| 130 | * automatically based on the code. |
| 131 | * </p> |
| 132 | * <p> |
| 133 | * In addition it also rewrites binder's RemoteException into either a |
| 134 | * CameraAccessException or an UnsupportedOperationException. |
| 135 | * </p> |
| 136 | * <p> |
| 137 | * As a result of calling any method on the proxy, RemoteException is |
| 138 | * guaranteed never to be thrown. |
| 139 | * </p> |
| 140 | * |
| 141 | * @param obj object that will serve as the target for all method calls |
| 142 | * @param <T> the type of the element you want to wrap. This must be an interface. |
| 143 | * @return a proxy that will intercept all invocations to obj |
| 144 | */ |
| 145 | public static <T> T newInstance(T obj) { |
| 146 | return Decorator.<T> newInstance(obj, new CameraBinderDecoratorListener()); |
| 147 | } |
| 148 | } |