Binder.cpp revision c5b2c0bf8007562536b822eb060fc54a01f8e08b 
1/*
2 * Copyright (C) 2005 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#include <binder/Binder.h>
18
19#include <utils/Atomic.h>
20#include <binder/BpBinder.h>
21#include <binder/IInterface.h>
22#include <binder/Parcel.h>
23
24#include <stdio.h>
25
26namespace android {
27
28// ---------------------------------------------------------------------------
29
30sp<IInterface>  IBinder::queryLocalInterface(const String16& descriptor)
31{
32    return NULL;
33}
34
35BBinder* IBinder::localBinder()
36{
37    return NULL;
38}
39
40BpBinder* IBinder::remoteBinder()
41{
42    return NULL;
43}
44
45bool IBinder::checkSubclass(const void* /*subclassID*/) const
46{
47    return false;
48}
49
50// ---------------------------------------------------------------------------
51
52class BBinder::Extras
53{
54public:
55    Mutex mLock;
56    BpBinder::ObjectManager mObjects;
57};
58
59// ---------------------------------------------------------------------------
60
61BBinder::BBinder()
62    : mExtras(NULL)
63{
64}
65
66bool BBinder::isBinderAlive() const
67{
68    return true;
69}
70
71status_t BBinder::pingBinder()
72{
73    return NO_ERROR;
74}
75
76String16 BBinder::getInterfaceDescriptor() const
77{
78    LOGW("reached BBinder::getInterfaceDescriptor (this=%p)", this);
79    return String16();
80}
81
82status_t BBinder::transact(
83    uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
84{
85    data.setDataPosition(0);
86
87    status_t err = NO_ERROR;
88    switch (code) {
89        case PING_TRANSACTION:
90            reply->writeInt32(pingBinder());
91            break;
92        default:
93            err = onTransact(code, data, reply, flags);
94            break;
95    }
96
97    if (reply != NULL) {
98        reply->setDataPosition(0);
99    }
100
101    return err;
102}
103
104status_t BBinder::linkToDeath(
105    const sp<DeathRecipient>& recipient, void* cookie, uint32_t flags)
106{
107    return INVALID_OPERATION;
108}
109
110status_t BBinder::unlinkToDeath(
111    const wp<DeathRecipient>& recipient, void* cookie, uint32_t flags,
112    wp<DeathRecipient>* outRecipient)
113{
114    return INVALID_OPERATION;
115}
116
117status_t BBinder::dump(int fd, const Vector<String16>& args)
118{
119    return NO_ERROR;
120}
121
122void BBinder::attachObject(
123    const void* objectID, void* object, void* cleanupCookie,
124    object_cleanup_func func)
125{
126    Extras* e = mExtras;
127
128    if (!e) {
129        e = new Extras;
130        if (android_atomic_cmpxchg(0, reinterpret_cast<int32_t>(e),
131                reinterpret_cast<volatile int32_t*>(&mExtras)) != 0) {
132            delete e;
133            e = mExtras;
134        }
135        if (e == 0) return; // out of memory
136    }
137
138    AutoMutex _l(e->mLock);
139    e->mObjects.attach(objectID, object, cleanupCookie, func);
140}
141
142void* BBinder::findObject(const void* objectID) const
143{
144    Extras* e = mExtras;
145    if (!e) return NULL;
146
147    AutoMutex _l(e->mLock);
148    return e->mObjects.find(objectID);
149}
150
151void BBinder::detachObject(const void* objectID)
152{
153    Extras* e = mExtras;
154    if (!e) return;
155
156    AutoMutex _l(e->mLock);
157    e->mObjects.detach(objectID);
158}
159
160BBinder* BBinder::localBinder()
161{
162    return this;
163}
164
165BBinder::~BBinder()
166{
167    if (mExtras) delete mExtras;
168}
169
170
171status_t BBinder::onTransact(
172    uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
173{
174    switch (code) {
175        case INTERFACE_TRANSACTION:
176            reply->writeString16(getInterfaceDescriptor());
177            return NO_ERROR;
178
179        case DUMP_TRANSACTION: {
180            int fd = data.readFileDescriptor();
181            int argc = data.readInt32();
182            Vector<String16> args;
183            for (int i = 0; i < argc && data.dataAvail() > 0; i++) {
184               args.add(data.readString16());
185            }
186            return dump(fd, args);
187        }
188        default:
189            return UNKNOWN_TRANSACTION;
190    }
191}
192
193// ---------------------------------------------------------------------------
194
195enum {
196    // This is used to transfer ownership of the remote binder from
197    // the BpRefBase object holding it (when it is constructed), to the
198    // owner of the BpRefBase object when it first acquires that BpRefBase.
199    kRemoteAcquired = 0x00000001
200};
201
202BpRefBase::BpRefBase(const sp<IBinder>& o)
203    : mRemote(o.get()), mRefs(NULL), mState(0)
204{
205    extendObjectLifetime(OBJECT_LIFETIME_WEAK);
206
207    if (mRemote) {
208        mRemote->incStrong(this);           // Removed on first IncStrong().
209        mRefs = mRemote->createWeak(this);  // Held for our entire lifetime.
210    }
211}
212
213BpRefBase::~BpRefBase()
214{
215    if (mRemote) {
216        if (!(mState&kRemoteAcquired)) {
217            mRemote->decStrong(this);
218        }
219        mRefs->decWeak(this);
220    }
221}
222
223void BpRefBase::onFirstRef()
224{
225    android_atomic_or(kRemoteAcquired, &mState);
226}
227
228void BpRefBase::onLastStrongRef(const void* id)
229{
230    if (mRemote) {
231        mRemote->decStrong(this);
232    }
233}
234
235bool BpRefBase::onIncStrongAttempted(uint32_t flags, const void* id)
236{
237    return mRemote ? mRefs->attemptIncStrong(this) : false;
238}
239
240// ---------------------------------------------------------------------------
241
242}; // namespace android
243