IBinder.h revision b0343a94fc1a573b1ecb1e92f2fcf1987ad7bbfe 
1/*
2 * Copyright (C) 2008 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#ifndef ANDROID_IBINDER_H
18#define ANDROID_IBINDER_H
19
20#include <utils/Errors.h>
21#include <utils/RefBase.h>
22#include <utils/String16.h>
23#include <utils/Vector.h>
24
25
26// linux/binder.h already defines this, but we can't just include it from there
27// because there are host builds that include this file.
28#ifndef B_PACK_CHARS
29#define B_PACK_CHARS(c1, c2, c3, c4) \
30    ((((c1)<<24)) | (((c2)<<16)) | (((c3)<<8)) | (c4))
31#endif  // B_PACK_CHARS
32
33// ---------------------------------------------------------------------------
34namespace android {
35
36class BBinder;
37class BpBinder;
38class IInterface;
39class Parcel;
40
41/**
42 * Base class and low-level protocol for a remotable object.
43 * You can derive from this class to create an object for which other
44 * processes can hold references to it.  Communication between processes
45 * (method calls, property get and set) is down through a low-level
46 * protocol implemented on top of the transact() API.
47 */
48class IBinder : public virtual RefBase
49{
50public:
51    enum {
52        FIRST_CALL_TRANSACTION  = 0x00000001,
53        LAST_CALL_TRANSACTION   = 0x00ffffff,
54
55        PING_TRANSACTION        = B_PACK_CHARS('_','P','N','G'),
56        DUMP_TRANSACTION        = B_PACK_CHARS('_','D','M','P'),
57        INTERFACE_TRANSACTION   = B_PACK_CHARS('_', 'N', 'T', 'F'),
58        SYSPROPS_TRANSACTION    = B_PACK_CHARS('_', 'S', 'P', 'R'),
59
60        // Corresponds to TF_ONE_WAY -- an asynchronous call.
61        FLAG_ONEWAY             = 0x00000001
62    };
63
64                          IBinder();
65
66    /**
67     * Check if this IBinder implements the interface named by
68     * @a descriptor.  If it does, the base pointer to it is returned,
69     * which you can safely static_cast<> to the concrete C++ interface.
70     */
71    virtual sp<IInterface>  queryLocalInterface(const String16& descriptor);
72
73    /**
74     * Return the canonical name of the interface provided by this IBinder
75     * object.
76     */
77    virtual const String16& getInterfaceDescriptor() const = 0;
78
79    virtual bool            isBinderAlive() const = 0;
80    virtual status_t        pingBinder() = 0;
81    virtual status_t        dump(int fd, const Vector<String16>& args) = 0;
82
83    virtual status_t        transact(   uint32_t code,
84                                        const Parcel& data,
85                                        Parcel* reply,
86                                        uint32_t flags = 0) = 0;
87
88    class DeathRecipient : public virtual RefBase
89    {
90    public:
91        virtual void binderDied(const wp<IBinder>& who) = 0;
92    };
93
94    /**
95     * Register the @a recipient for a notification if this binder
96     * goes away.  If this binder object unexpectedly goes away
97     * (typically because its hosting process has been killed),
98     * then DeathRecipient::binderDied() will be called with a reference
99     * to this.
100     *
101     * The @a cookie is optional -- if non-NULL, it should be a
102     * memory address that you own (that is, you know it is unique).
103     *
104     * @note You will only receive death notifications for remote binders,
105     * as local binders by definition can't die without you dying as well.
106     * Trying to use this function on a local binder will result in an
107     * INVALID_OPERATION code being returned and nothing happening.
108     *
109     * @note This link always holds a weak reference to its recipient.
110     *
111     * @note You will only receive a weak reference to the dead
112     * binder.  You should not try to promote this to a strong reference.
113     * (Nor should you need to, as there is nothing useful you can
114     * directly do with it now that it has passed on.)
115     */
116    virtual status_t        linkToDeath(const sp<DeathRecipient>& recipient,
117                                        void* cookie = NULL,
118                                        uint32_t flags = 0) = 0;
119
120    /**
121     * Remove a previously registered death notification.
122     * The @a recipient will no longer be called if this object
123     * dies.  The @a cookie is optional.  If non-NULL, you can
124     * supply a NULL @a recipient, and the recipient previously
125     * added with that cookie will be unlinked.
126     */
127    virtual status_t        unlinkToDeath(  const wp<DeathRecipient>& recipient,
128                                            void* cookie = NULL,
129                                            uint32_t flags = 0,
130                                            wp<DeathRecipient>* outRecipient = NULL) = 0;
131
132    virtual bool            checkSubclass(const void* subclassID) const;
133
134    typedef void (*object_cleanup_func)(const void* id, void* obj, void* cleanupCookie);
135
136    virtual void            attachObject(   const void* objectID,
137                                            void* object,
138                                            void* cleanupCookie,
139                                            object_cleanup_func func) = 0;
140    virtual void*           findObject(const void* objectID) const = 0;
141    virtual void            detachObject(const void* objectID) = 0;
142
143    virtual BBinder*        localBinder();
144    virtual BpBinder*       remoteBinder();
145
146protected:
147    virtual          ~IBinder();
148
149private:
150};
151
152}; // namespace android
153
154// ---------------------------------------------------------------------------
155
156#endif // ANDROID_IBINDER_H
157