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      1 /*
      2  * Copyright 2012, 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 MEDIA_CODEC_LIST_WRITER_H_
     18 
     19 #define MEDIA_CODEC_LIST_WRITER_H_
     20 
     21 #include <media/stagefright/foundation/ABase.h>
     22 #include <media/stagefright/MediaCodecListWriter.h>
     23 #include <media/MediaCodecInfo.h>
     24 
     25 #include <utils/Errors.h>
     26 #include <utils/StrongPointer.h>
     27 
     28 namespace android {
     29 
     30 /**
     31  * This class is to be used by a `MediaCodecListBuilderBase` instance to add
     32  * information to the destination `MediaCodecList` object.
     33  */
     34 struct MediaCodecListWriter {
     35     /**
     36      * Add a key-value pair to a `MediaCodecList`'s global settings.
     37      *
     38      * @param key Key.
     39      * @param value Value.
     40      */
     41     void addGlobalSetting(const char* key, const char* value);
     42     /**
     43      * Create an add a new `MediaCodecInfo` object for a `MediaCodecList`, and
     44      * return a `MediaCodecInfoWriter` object associated with the newly added
     45      * `MediaCodecInfo`.
     46      *
     47      * @return The `MediaCodecInfoWriter` object associated with the newly
     48      * added `MediaCodecInfo` object.
     49      */
     50     std::unique_ptr<MediaCodecInfoWriter> addMediaCodecInfo();
     51     /**
     52      * Find an existing `MediaCodecInfo` object for a codec name and return a
     53      * `MediaCodecInfoWriter` object associated with the found added `MediaCodecInfo`.
     54      *
     55      * @return The `MediaCodecInfoWriter` object if found, or nullptr if not found.
     56      */
     57     std::unique_ptr<MediaCodecInfoWriter> findMediaCodecInfo(const char *codecName);
     58 private:
     59     MediaCodecListWriter() = default;
     60 
     61     void writeGlobalSettings(const sp<AMessage> &globalSettings) const;
     62     void writeCodecInfos(std::vector<sp<MediaCodecInfo>> *codecInfos) const;
     63 
     64     std::vector<std::pair<std::string, std::string>> mGlobalSettings;
     65     std::vector<sp<MediaCodecInfo>> mCodecInfos;
     66 
     67     friend struct MediaCodecList;
     68 };
     69 
     70 /**
     71  * This interface is to be used by `MediaCodecList` to fill its members with
     72  * appropriate information. `buildMediaCodecList()` will be called from a
     73  * `MediaCodecList` object during its construction.
     74  */
     75 struct MediaCodecListBuilderBase {
     76     /**
     77      * Build the `MediaCodecList` via the given `MediaCodecListWriter` interface.
     78      *
     79      * @param writer The writer interface.
     80      * @return The status of the construction. `NO_ERROR` means success.
     81      */
     82     virtual status_t buildMediaCodecList(MediaCodecListWriter* writer) = 0;
     83 
     84     /**
     85      * The default destructor does nothing.
     86      */
     87     virtual ~MediaCodecListBuilderBase() = default;
     88 
     89     typedef MediaCodecListBuilderBase *(*CreateBuilderFunc)(void);
     90 };
     91 
     92 }  // namespace android
     93 
     94 #endif  // MEDIA_CODEC_LIST_WRITER_H_
     95 
     96