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      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 
     26 namespace android {
     27 
     28 struct ABuffer;
     29 struct AHandler;
     30 struct AString;
     31 class Parcel;
     32 
     33 struct AReplyToken : public RefBase {
     34     AReplyToken(const sp<ALooper> &looper)
     35         : mLooper(looper),
     36           mReplied(false) {
     37     }
     38 
     39 private:
     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 
     61 struct AMessage : public RefBase {
     62     AMessage();
     63     AMessage(uint32_t what, const sp<const AHandler> &handler);
     64 
     65     static sp<AMessage> FromParcel(const Parcel &parcel);
     66     void writeToParcel(Parcel *parcel) const;
     67 
     68     void setWhat(uint32_t what);
     69     uint32_t what() const;
     70 
     71     void setTarget(const sp<const AHandler> &handler);
     72 
     73     void clear();
     74 
     75     void setInt32(const char *name, int32_t value);
     76     void setInt64(const char *name, int64_t value);
     77     void setSize(const char *name, size_t value);
     78     void setFloat(const char *name, float value);
     79     void setDouble(const char *name, double value);
     80     void setPointer(const char *name, void *value);
     81     void setString(const char *name, const char *s, ssize_t len = -1);
     82     void setString(const char *name, const AString &s);
     83     void setObject(const char *name, const sp<RefBase> &obj);
     84     void setBuffer(const char *name, const sp<ABuffer> &buffer);
     85     void setMessage(const char *name, const sp<AMessage> &obj);
     86 
     87     void setRect(
     88             const char *name,
     89             int32_t left, int32_t top, int32_t right, int32_t bottom);
     90 
     91     bool contains(const char *name) const;
     92 
     93     bool findInt32(const char *name, int32_t *value) const;
     94     bool findInt64(const char *name, int64_t *value) const;
     95     bool findSize(const char *name, size_t *value) const;
     96     bool findFloat(const char *name, float *value) const;
     97     bool findDouble(const char *name, double *value) const;
     98     bool findPointer(const char *name, void **value) const;
     99     bool findString(const char *name, AString *value) const;
    100     bool findObject(const char *name, sp<RefBase> *obj) const;
    101     bool findBuffer(const char *name, sp<ABuffer> *buffer) const;
    102     bool findMessage(const char *name, sp<AMessage> *obj) const;
    103 
    104     bool findRect(
    105             const char *name,
    106             int32_t *left, int32_t *top, int32_t *right, int32_t *bottom) const;
    107 
    108     status_t post(int64_t delayUs = 0);
    109 
    110     // Posts the message to its target and waits for a response (or error)
    111     // before returning.
    112     status_t postAndAwaitResponse(sp<AMessage> *response);
    113 
    114     // If this returns true, the sender of this message is synchronously
    115     // awaiting a response and the reply token is consumed from the message
    116     // and stored into replyID. The reply token must be used to send the response
    117     // using "postReply" below.
    118     bool senderAwaitsResponse(sp<AReplyToken> *replyID);
    119 
    120     // Posts the message as a response to a reply token.  A reply token can
    121     // only be used once. Returns OK if the response could be posted; otherwise,
    122     // an error.
    123     status_t postReply(const sp<AReplyToken> &replyID);
    124 
    125     // Performs a deep-copy of "this", contained messages are in turn "dup'ed".
    126     // Warning: RefBase items, i.e. "objects" are _not_ copied but only have
    127     // their refcount incremented.
    128     sp<AMessage> dup() const;
    129 
    130     AString debugString(int32_t indent = 0) const;
    131 
    132     enum Type {
    133         kTypeInt32,
    134         kTypeInt64,
    135         kTypeSize,
    136         kTypeFloat,
    137         kTypeDouble,
    138         kTypePointer,
    139         kTypeString,
    140         kTypeObject,
    141         kTypeMessage,
    142         kTypeRect,
    143         kTypeBuffer,
    144     };
    145 
    146     size_t countEntries() const;
    147     const char *getEntryNameAt(size_t index, Type *type) const;
    148 
    149 protected:
    150     virtual ~AMessage();
    151 
    152 private:
    153     friend struct ALooper; // deliver()
    154 
    155     uint32_t mWhat;
    156 
    157     // used only for debugging
    158     ALooper::handler_id mTarget;
    159 
    160     wp<AHandler> mHandler;
    161     wp<ALooper> mLooper;
    162 
    163     struct Rect {
    164         int32_t mLeft, mTop, mRight, mBottom;
    165     };
    166 
    167     struct Item {
    168         union {
    169             int32_t int32Value;
    170             int64_t int64Value;
    171             size_t sizeValue;
    172             float floatValue;
    173             double doubleValue;
    174             void *ptrValue;
    175             RefBase *refValue;
    176             AString *stringValue;
    177             Rect rectValue;
    178         } u;
    179         const char *mName;
    180         size_t      mNameLength;
    181         Type mType;
    182         void setName(const char *name, size_t len);
    183     };
    184 
    185     enum {
    186         kMaxNumItems = 64
    187     };
    188     Item mItems[kMaxNumItems];
    189     size_t mNumItems;
    190 
    191     Item *allocateItem(const char *name);
    192     void freeItemValue(Item *item);
    193     const Item *findItem(const char *name, Type type) const;
    194 
    195     void setObjectInternal(
    196             const char *name, const sp<RefBase> &obj, Type type);
    197 
    198     size_t findItemIndex(const char *name, size_t len) const;
    199 
    200     void deliver();
    201 
    202     DISALLOW_EVIL_CONSTRUCTORS(AMessage);
    203 };
    204 
    205 }  // namespace android
    206 
    207 #endif  // A_MESSAGE_H_
    208