first commit

nodes/vp_stream_status_hookable.h

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+#pragma once
+
+#include <functional>
+#include <mutex>
+#include <string>
+#include <memory>
+
+namespace vp_nodes {
+    // stream status created by des nodes.
+    struct vp_stream_status {
+        int channel_index = -1;  // channel index
+        int frame_index = -1;    // latest frame index
+        int latency = 0;         // latency(ms) relative to src node
+
+        float fps = 0;           // output fps of stream, maybe it is not equal to original_fps
+        int width = 0;           // output width of stream, maybe it is not equal to original_width
+        int height = 0;          // output height of stream, maybe it is not equal to original_height
+        std::string direction;   // where the stream goes to
+    };
+
+    // callback when stream is going out of pipe, happens in des nodes. MUST not be blocked.
+    typedef std::function<void(std::string, vp_stream_status)> vp_stream_status_hooker;
+
+    // allow hookers attached to the pipe (des nodes specifically), hookers get notified when stream is going out of pipe.
+    // this class is inherited by vp_des_node only.
+    class vp_stream_status_hookable
+    {
+    private:
+        /* data */
+    protected:
+        std::mutex stream_status_hooker_lock;
+        vp_stream_status_hooker stream_status_hooker;
+    public:
+        vp_stream_status_hookable(/* args */) {}
+        ~vp_stream_status_hookable() {}
+        
+        void set_stream_status_hooker(vp_stream_status_hooker stream_status_hooker) {
+            std::lock_guard<std::mutex> guard(stream_status_hooker_lock);
+            this->stream_status_hooker = stream_status_hooker;
+        }
+
+        void invoke_stream_status_hooker(std::string node_name, vp_stream_status stream_status) {
+            std::lock_guard<std::mutex> guard(stream_status_hooker_lock);
+            if (this->stream_status_hooker) {
+                this->stream_status_hooker(node_name, stream_status);
+            }
+        }
+    };
+}