Binder.cpp revision 83c0446f27b9542d6c2e724817b2b2d8d1f55085 
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
30IBinder::IBinder()
31    : RefBase()
32{
33}
34
35IBinder::~IBinder()
36{
37}
38
39// ---------------------------------------------------------------------------
40
41sp<IInterface>  IBinder::queryLocalInterface(const String16& descriptor)
42{
43    return NULL;
44}
45
46BBinder* IBinder::localBinder()
47{
48    return NULL;
49}
50
51BpBinder* IBinder::remoteBinder()
52{
53    return NULL;
54}
55
56bool IBinder::checkSubclass(const void* /*subclassID*/) const
57{
58    return false;
59}
60
61// ---------------------------------------------------------------------------
62
63class BBinder::Extras
64{
65public:
66    Mutex mLock;
67    BpBinder::ObjectManager mObjects;
68};
69
70// ---------------------------------------------------------------------------
71
72String16 BBinder::sEmptyDescriptor;
73
74BBinder::BBinder()
75    : mExtras(NULL)
76{
77}
78
79bool BBinder::isBinderAlive() const
80{
81    return true;
82}
83
84status_t BBinder::pingBinder()
85{
86    return NO_ERROR;
87}
88
89const String16& BBinder::getInterfaceDescriptor() const
90{
91    LOGW("reached BBinder::getInterfaceDescriptor (this=%p)", this);
92    return sEmptyDescriptor;
93}
94
95status_t BBinder::transact(
96    uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
97{
98    data.setDataPosition(0);
99
100    status_t err = NO_ERROR;
101    switch (code) {
102        case PING_TRANSACTION:
103            reply->writeInt32(pingBinder());
104            break;
105        default:
106            err = onTransact(code, data, reply, flags);
107            break;
108    }
109
110    if (reply != NULL) {
111        reply->setDataPosition(0);
112    }
113
114    return err;
115}
116
117status_t BBinder::linkToDeath(
118    const sp<DeathRecipient>& recipient, void* cookie, uint32_t flags)
119{
120    return INVALID_OPERATION;
121}
122
123status_t BBinder::unlinkToDeath(
124    const wp<DeathRecipient>& recipient, void* cookie, uint32_t flags,
125    wp<DeathRecipient>* outRecipient)
126{
127    return INVALID_OPERATION;
128}
129
130status_t BBinder::dump(int fd, const Vector<String16>& args)
131{
132    return NO_ERROR;
133}
134
135void BBinder::attachObject(
136    const void* objectID, void* object, void* cleanupCookie,
137    object_cleanup_func func)
138{
139    Extras* e = mExtras;
140
141    if (!e) {
142        e = new Extras;
143        if (android_atomic_cmpxchg(0, reinterpret_cast<int32_t>(e),
144                reinterpret_cast<volatile int32_t*>(&mExtras)) != 0) {
145            delete e;
146            e = mExtras;
147        }
148        if (e == 0) return; // out of memory
149    }
150
151    AutoMutex _l(e->mLock);
152    e->mObjects.attach(objectID, object, cleanupCookie, func);
153}
154
155void* BBinder::findObject(const void* objectID) const
156{
157    Extras* e = mExtras;
158    if (!e) return NULL;
159
160    AutoMutex _l(e->mLock);
161    return e->mObjects.find(objectID);
162}
163
164void BBinder::detachObject(const void* objectID)
165{
166    Extras* e = mExtras;
167    if (!e) return;
168
169    AutoMutex _l(e->mLock);
170    e->mObjects.detach(objectID);
171}
172
173BBinder* BBinder::localBinder()
174{
175    return this;
176}
177
178BBinder::~BBinder()
179{
180    if (mExtras) delete mExtras;
181}
182
183
184status_t BBinder::onTransact(
185    uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
186{
187    switch (code) {
188        case INTERFACE_TRANSACTION:
189            reply->writeString16(getInterfaceDescriptor());
190            return NO_ERROR;
191
192        case DUMP_TRANSACTION: {
193            int fd = data.readFileDescriptor();
194            int argc = data.readInt32();
195            Vector<String16> args;
196            for (int i = 0; i < argc && data.dataAvail() > 0; i++) {
197               args.add(data.readString16());
198            }
199            return dump(fd, args);
200        }
201        default:
202            return UNKNOWN_TRANSACTION;
203    }
204}
205
206// ---------------------------------------------------------------------------
207
208enum {
209    // This is used to transfer ownership of the remote binder from
210    // the BpRefBase object holding it (when it is constructed), to the
211    // owner of the BpRefBase object when it first acquires that BpRefBase.
212    kRemoteAcquired = 0x00000001
213};
214
215BpRefBase::BpRefBase(const sp<IBinder>& o)
216    : mRemote(o.get()), mRefs(NULL), mState(0)
217{
218    extendObjectLifetime(OBJECT_LIFETIME_WEAK);
219
220    if (mRemote) {
221        mRemote->incStrong(this);           // Removed on first IncStrong().
222        mRefs = mRemote->createWeak(this);  // Held for our entire lifetime.
223    }
224}
225
226BpRefBase::~BpRefBase()
227{
228    if (mRemote) {
229        if (!(mState&kRemoteAcquired)) {
230            mRemote->decStrong(this);
231        }
232        mRefs->decWeak(this);
233    }
234}
235
236void BpRefBase::onFirstRef()
237{
238    android_atomic_or(kRemoteAcquired, &mState);
239}
240
241void BpRefBase::onLastStrongRef(const void* id)
242{
243    if (mRemote) {
244        mRemote->decStrong(this);
245    }
246}
247
248bool BpRefBase::onIncStrongAttempted(uint32_t flags, const void* id)
249{
250    return mRemote ? mRefs->attemptIncStrong(this) : false;
251}
252
253// ---------------------------------------------------------------------------
254
255}; // namespace android
256