first commit

nodes/vp_meta_publisher.cpp

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+
+
+#include "vp_meta_publisher.h"
+
+namespace vp_nodes {
+    vp_meta_publisher::vp_meta_publisher(/* args */) {
+
+    }
+
+    vp_meta_publisher::~vp_meta_publisher() {
+
+    }
+
+    void vp_meta_publisher::add_subscriber(std::shared_ptr<vp_meta_subscriber> subscriber) {
+        std::lock_guard<std::mutex> guard(this->subscribers_lock);
+        this->subscribers.push_back(subscriber);
+    }
+
+    void vp_meta_publisher::remove_subscriber(std::shared_ptr<vp_meta_subscriber> subscriber) {
+        std::lock_guard<std::mutex> guard(this->subscribers_lock);
+        for (auto i = this->subscribers.begin(); i != this->subscribers.end();) {
+            if(*i == subscriber) {
+                i = this->subscribers.erase(i);
+            }
+            else {
+                i++;
+            }
+        }     
+    }
+
+    // by default, we push meta to next nodes indiscriminately, each next node has the same meta pointer.
+    // in some situations, we need push meta depend on condition, refer to vp_split_node which would push meta by channel index or push a deep copy pf meta(new pointer to new memory). 
+    void vp_meta_publisher::push_meta(std::shared_ptr<vp_objects::vp_meta> meta) {
+        std::lock_guard<std::mutex> guard(this->subscribers_lock);
+        for (auto i = this->subscribers.begin(); i != this->subscribers.end(); i++) {
+            (*i)->meta_flow(meta);
+        }
+    }
+}