Add example project for h264 and opus streaming

examples/streamer/dispatchqueue.cpp

@@ -0,0 +1,94 @@
+/*
+ * libdatachannel streamer example
+ * Copyright (c) 2020 Filip Klembara (in2core)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+#include "dispatchqueue.hpp"
+
+DispatchQueue::DispatchQueue(std::string name, size_t threadCount) :
+    name{std::move(name)}, threads(threadCount) {
+    for(size_t i = 0; i < threads.size(); i++)
+    {
+        threads[i] = std::thread(&DispatchQueue::dispatchThreadHandler, this);
+    }
+}
+
+DispatchQueue::~DispatchQueue() {
+    // Signal to dispatch threads that it's time to wrap up
+    std::unique_lock<std::mutex> lock(lockMutex);
+    quit = true;
+    lock.unlock();
+    condition.notify_all();
+
+    // Wait for threads to finish before we exit
+    for(size_t i = 0; i < threads.size(); i++)
+    {
+        if(threads[i].joinable())
+        {
+            threads[i].join();
+        }
+    }
+}
+
+void DispatchQueue::removePending() {
+    std::unique_lock<std::mutex> lock(lockMutex);
+    queue = {};
+}
+
+void DispatchQueue::dispatch(const fp_t& op) {
+    std::unique_lock<std::mutex> lock(lockMutex);
+    queue.push(op);
+
+    // Manual unlocking is done before notifying, to avoid waking up
+    // the waiting thread only to block again (see notify_one for details)
+    lock.unlock();
+    condition.notify_one();
+}
+
+void DispatchQueue::dispatch(fp_t&& op) {
+    std::unique_lock<std::mutex> lock(lockMutex);
+    queue.push(std::move(op));
+
+    // Manual unlocking is done before notifying, to avoid waking up
+    // the waiting thread only to block again (see notify_one for details)
+    lock.unlock();
+    condition.notify_one();
+}
+
+void DispatchQueue::dispatchThreadHandler(void) {
+    std::unique_lock<std::mutex> lock(lockMutex);
+    do {
+        //Wait until we have data or a quit signal
+        condition.wait(lock, [this]{
+            return (queue.size() || quit);
+        });
+
+        //after wait, we own the lock
+        if(!quit && queue.size())
+        {
+            auto op = std::move(queue.front());
+            queue.pop();
+
+            //unlock now that we're done messing with the queue
+            lock.unlock();
+
+            op();
+
+            lock.lock();
+        }
+    } while (!quit);
+}