feat(dca): add DCA direct component access

Signed-off-by: pingkai <pingkai010@gmail.com>

framework/base/IDCA.h

@@ -0,0 +1,35 @@
+//
+// Created by moqi on 2020/6/24.
+//
+
+#ifndef CICADAMEDIA_IDCA_H
+#define CICADAMEDIA_IDCA_H
+#include <string>
+// direct component access
+namespace Cicada {
+    class IDCAObserver {
+    public:
+        virtual void onEvent(int level, const std::string &content) = 0;
+    };
+    class IDCA {
+    public:
+        void setDCAObserver(IDCAObserver *observer)
+        {
+            mObserver = observer;
+        }
+        virtual int invoke(int cmd, const std::string &content) = 0;
+        virtual ~IDCA() = default;
+
+    protected:
+        void sendEvent(int level, const std::string &content)
+        {
+            if (mObserver) {
+                mObserver->onEvent(level, content);
+            }
+        };
+
+    private:
+        IDCAObserver *mObserver{nullptr};
+    };
+}// namespace Cicada
+#endif//CICADAMEDIA_IDCA_H

framework/demuxer/IDemuxer.h

@@ -9,15 +9,16 @@
 #include "utils/AFMediaType.h"
 #include "play_list/playList.h"
 
+#include "DemuxerMetaInfo.h"
+#include <base/IDCA.h>
+#include <base/OptionOwner.h>
+#include <base/media/IAFPacket.h>
+#include <data_source/IDataSource.h>
 #include <functional>
 #include <string>
 #include <utility>
 #include <utils/CicadaType.h>
-#include <base/media/IAFPacket.h>
 #include <utils/mediaTypeInternal.h>
-#include <base/OptionOwner.h>
-#include <data_source/IDataSource.h>
-#include "DemuxerMetaInfo.h"
 
 namespace Cicada {
     typedef enum demuxer_type {
@@ -28,7 +29,7 @@ namespace Cicada {
     } demuxer_type;
 
 
-    class CICADA_CPLUS_EXTERN IDemuxer : public OptionOwner {
+    class CICADA_CPLUS_EXTERN IDemuxer : public OptionOwner, public IDCA {
     public:
 
 
@@ -165,6 +166,11 @@ namespace Cicada {
             return false;
         }
 
+        int invoke(int cmd, const std::string &content) override
+        {
+            return 0;
+        }
+
     protected:
         demuxer_callback_read mReadCb{nullptr};
         demuxer_callback_seek mSeekCb{nullptr};