1/*
2 * Copyright (C) 2010 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 A_MESSAGE_H_
18
19#define A_MESSAGE_H_
20
21#include <media/stagefright/foundation/ABase.h>
22#include <media/stagefright/foundation/ALooper.h>
23#include <utils/KeyedVector.h>
24#include <utils/RefBase.h>
25
26namespace android {
27
28struct ABuffer;
29struct AHandler;
30struct AString;
31class Parcel;
32
33struct AReplyToken : public RefBase {
34    AReplyToken(const sp<ALooper> &looper)
35        : mLooper(looper),
36          mReplied(false) {
37    }
38
39private:
40    friend struct AMessage;
41    friend struct ALooper;
42    wp<ALooper> mLooper;
43    sp<AMessage> mReply;
44    bool mReplied;
45
46    sp<ALooper> getLooper() const {
47        return mLooper.promote();
48    }
49    // if reply is not set, returns false; otherwise, it retrieves the reply and returns true
50    bool retrieveReply(sp<AMessage> *reply) {
51        if (mReplied) {
52            *reply = mReply;
53            mReply.clear();
54        }
55        return mReplied;
56    }
57    // sets the reply for this token. returns OK or error
58    status_t setReply(const sp<AMessage> &reply);
59};
60
61struct AMessage : public RefBase {
62    AMessage();
63    AMessage(uint32_t what, const sp<const AHandler> &handler);
64
65    // Construct an AMessage from a parcel.
66    // nestingAllowed determines how many levels AMessage can be nested inside
67    // AMessage. The default value here is arbitrarily set to 255.
68    // FromParcel() returns NULL on error, which occurs when the input parcel
69    // contains
70    // - an AMessage nested deeper than maxNestingLevel; or
71    // - an item whose type is not recognized by this function.
72    // Types currently recognized by this function are:
73    //   Item types      set/find function suffixes
74    //   ==========================================
75    //     int32_t                Int32
76    //     int64_t                Int64
77    //     size_t                 Size
78    //     float                  Float
79    //     double                 Double
80    //     AString                String
81    //     AMessage               Message
82    static sp<AMessage> FromParcel(const Parcel &parcel,
83                                   size_t maxNestingLevel = 255);
84
85    // Write this AMessage to a parcel.
86    // All items in the AMessage must have types that are recognized by
87    // FromParcel(); otherwise, TRESPASS error will occur.
88    void writeToParcel(Parcel *parcel) const;
89
90    void setWhat(uint32_t what);
91    uint32_t what() const;
92
93    void setTarget(const sp<const AHandler> &handler);
94
95    void clear();
96
97    void setInt32(const char *name, int32_t value);
98    void setInt64(const char *name, int64_t value);
99    void setSize(const char *name, size_t value);
100    void setFloat(const char *name, float value);
101    void setDouble(const char *name, double value);
102    void setPointer(const char *name, void *value);
103    void setString(const char *name, const char *s, ssize_t len = -1);
104    void setString(const char *name, const AString &s);
105    void setObject(const char *name, const sp<RefBase> &obj);
106    void setBuffer(const char *name, const sp<ABuffer> &buffer);
107    void setMessage(const char *name, const sp<AMessage> &obj);
108
109    void setRect(
110            const char *name,
111            int32_t left, int32_t top, int32_t right, int32_t bottom);
112
113    bool contains(const char *name) const;
114
115    bool findInt32(const char *name, int32_t *value) const;
116    bool findInt64(const char *name, int64_t *value) const;
117    bool findSize(const char *name, size_t *value) const;
118    bool findFloat(const char *name, float *value) const;
119    bool findDouble(const char *name, double *value) const;
120    bool findPointer(const char *name, void **value) const;
121    bool findString(const char *name, AString *value) const;
122    bool findObject(const char *name, sp<RefBase> *obj) const;
123    bool findBuffer(const char *name, sp<ABuffer> *buffer) const;
124    bool findMessage(const char *name, sp<AMessage> *obj) const;
125
126    bool findRect(
127            const char *name,
128            int32_t *left, int32_t *top, int32_t *right, int32_t *bottom) const;
129
130    status_t post(int64_t delayUs = 0);
131
132    // Posts the message to its target and waits for a response (or error)
133    // before returning.
134    status_t postAndAwaitResponse(sp<AMessage> *response);
135
136    // If this returns true, the sender of this message is synchronously
137    // awaiting a response and the reply token is consumed from the message
138    // and stored into replyID. The reply token must be used to send the response
139    // using "postReply" below.
140    bool senderAwaitsResponse(sp<AReplyToken> *replyID);
141
142    // Posts the message as a response to a reply token.  A reply token can
143    // only be used once. Returns OK if the response could be posted; otherwise,
144    // an error.
145    status_t postReply(const sp<AReplyToken> &replyID);
146
147    // Performs a deep-copy of "this", contained messages are in turn "dup'ed".
148    // Warning: RefBase items, i.e. "objects" are _not_ copied but only have
149    // their refcount incremented.
150    sp<AMessage> dup() const;
151
152    // Performs a shallow or deep comparison of |this| and |other| and returns
153    // an AMessage with the differences.
154    // Warning: RefBase items, i.e. "objects" are _not_ copied but only have
155    // their refcount incremented.
156    // This is true for AMessages that have no corresponding AMessage equivalent in |other|.
157    // (E.g. there is no such key or the type is different.) On the other hand, changes in
158    // the AMessage (or AMessages if deep is |false|) are returned in new objects.
159    sp<AMessage> changesFrom(const sp<const AMessage> &other, bool deep = false) const;
160
161    AString debugString(int32_t indent = 0) const;
162
163    enum Type {
164        kTypeInt32,
165        kTypeInt64,
166        kTypeSize,
167        kTypeFloat,
168        kTypeDouble,
169        kTypePointer,
170        kTypeString,
171        kTypeObject,
172        kTypeMessage,
173        kTypeRect,
174        kTypeBuffer,
175    };
176
177    size_t countEntries() const;
178    const char *getEntryNameAt(size_t index, Type *type) const;
179
180protected:
181    virtual ~AMessage();
182
183private:
184    friend struct ALooper; // deliver()
185
186    uint32_t mWhat;
187
188    // used only for debugging
189    ALooper::handler_id mTarget;
190
191    wp<AHandler> mHandler;
192    wp<ALooper> mLooper;
193
194    struct Rect {
195        int32_t mLeft, mTop, mRight, mBottom;
196    };
197
198    struct Item {
199        union {
200            int32_t int32Value;
201            int64_t int64Value;
202            size_t sizeValue;
203            float floatValue;
204            double doubleValue;
205            void *ptrValue;
206            RefBase *refValue;
207            AString *stringValue;
208            Rect rectValue;
209        } u;
210        const char *mName;
211        size_t      mNameLength;
212        Type mType;
213        void setName(const char *name, size_t len);
214    };
215
216    enum {
217        kMaxNumItems = 64
218    };
219    Item mItems[kMaxNumItems];
220    size_t mNumItems;
221
222    Item *allocateItem(const char *name);
223    void freeItemValue(Item *item);
224    const Item *findItem(const char *name, Type type) const;
225
226    void setObjectInternal(
227            const char *name, const sp<RefBase> &obj, Type type);
228
229    size_t findItemIndex(const char *name, size_t len) const;
230
231    void deliver();
232
233    DISALLOW_EVIL_CONSTRUCTORS(AMessage);
234};
235
236}  // namespace android
237
238#endif  // A_MESSAGE_H_
239