SoundPlayer: Added playback controls

The playback of a file can now be paused, stopped, continued and the
user can seek to any part of the file.

Applications/SoundPlayer/PlaybackManager.cpp

@@ -0,0 +1,134 @@
+#include "PlaybackManager.h"
+
+PlaybackManager::PlaybackManager(NonnullRefPtr<AClientConnection> connection, AWavLoader& loader)
+    : m_loader(loader)
+    , m_connection(connection)
+{
+    m_total_length = loader.total_samples() / static_cast<float>(loader.sample_rate());
+    m_timer = CTimer::construct(100, [&]() { next_buffer(); });
+    pause();
+}
+
+PlaybackManager::~PlaybackManager()
+{
+}
+
+void PlaybackManager::stop()
+{
+    set_paused(true);
+    m_connection->clear_buffer(true);
+    m_buffers.clear();
+    m_loader.reset();
+    m_last_seek = 0;
+    m_next_buffer = nullptr;
+    m_current_buffer = nullptr;
+    m_next_ptr = 0;
+}
+
+void PlaybackManager::play()
+{
+    set_paused(false);
+}
+
+void PlaybackManager::seek(const int position)
+{
+    m_last_seek = position;
+    bool paused_state = m_paused;
+    set_paused(true);
+
+    m_connection->clear_buffer(true);
+    m_next_buffer = nullptr;
+    m_current_buffer = nullptr;
+    m_next_ptr = 0;
+    m_buffers.clear();
+    m_loader.seek(position);
+
+    if (!paused_state)
+        set_paused(false);
+}
+
+void PlaybackManager::pause()
+{
+    set_paused(true);
+}
+
+void PlaybackManager::remove_dead_buffers()
+{
+    int id = m_connection->get_playing_buffer();
+    int current_id = -1;
+    if (m_current_buffer)
+        current_id = m_current_buffer->shared_buffer_id();
+
+    if (id >= 0 && id != current_id) {
+        while (!m_buffers.is_empty()) {
+            --m_next_ptr;
+            auto buffer = m_buffers.take_first();
+
+            if (buffer->shared_buffer_id() == id) {
+                m_current_buffer = buffer;
+                break;
+            }
+        }
+    }
+}
+
+void PlaybackManager::load_next_buffer()
+{
+    if (m_buffers.size() < 10) {
+        for (int i = 0; i < 20 && m_loader.loaded_samples() < m_loader.total_samples(); i++) {
+            auto buffer = m_loader.get_more_samples(PLAYBACK_MANAGER_BUFFER_SIZE);
+            if (buffer)
+                m_buffers.append(buffer);
+        }
+    }
+
+    if (m_next_ptr < m_buffers.size()) {
+        m_next_buffer = m_buffers.at(m_next_ptr++);
+    } else {
+        m_next_buffer = nullptr;
+    }
+}
+
+void PlaybackManager::set_paused(bool paused)
+{
+    if (!m_next_buffer)
+        load_next_buffer();
+
+    m_paused = paused;
+    m_connection->set_paused(paused);
+}
+
+bool PlaybackManager::toggle_pause()
+{
+    if (m_paused) {
+        play();
+    } else {
+        pause();
+    }
+    return m_paused;
+}
+
+void PlaybackManager::next_buffer()
+{
+    if (on_update)
+        on_update();
+
+    if (m_paused)
+        return;
+
+    remove_dead_buffers();
+    if (!m_next_buffer) {
+        if (!m_connection->get_remaining_samples() && !m_paused) {
+            dbg() << "Exhausted samples :^)";
+            stop();
+        }
+
+        return;
+    }
+
+    bool enqueued = m_connection->try_enqueue(*m_next_buffer);
+    if (!enqueued)
+        return;
+
+    load_next_buffer();
+}