AudioServer: Persist audio settings with a config file

AudioServer loads its settings, currently volume and mute state, from a
user config file "Audio.ini". Additionally, the current settings are
stored every ten seconds, if necessary. This allows for persistent audio
settings in between boots.

Userland/Services/AudioServer/Mixer.cpp

@@ -1,21 +1,25 @@
 /*
  * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2021, kleines Filmröllchen <malu.bertsch@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include "Mixer.h"
 #include <AK/Array.h>
 #include <AK/MemoryStream.h>
 #include <AK/NumericLimits.h>
 #include <AudioServer/ClientConnection.h>
 #include <AudioServer/Mixer.h>
+#include <LibCore/ConfigFile.h>
+#include <LibCore/Timer.h>
 #include <pthread.h>
 
 namespace AudioServer {
 
 u8 Mixer::m_zero_filled_buffer[4096];
 
-Mixer::Mixer()
+Mixer::Mixer(NonnullRefPtr<Core::ConfigFile> config)
     : m_device(Core::File::construct("/dev/audio", this))
     , m_sound_thread(Threading::Thread::construct(
           [this] {
@@ -23,6 +27,7 @@ Mixer::Mixer()
               return 0;
           },
           "AudioServer[mixer]"))
+    , m_config(move(config))
 {
     if (!m_device->open(Core::OpenMode::WriteOnly)) {
         dbgln("Can't open audio device: {}", m_device->error_string());
@@ -32,6 +37,9 @@ Mixer::Mixer()
     pthread_mutex_init(&m_pending_mutex, nullptr);
     pthread_cond_init(&m_pending_cond, nullptr);
 
+    m_muted = m_config->read_bool_entry("Master", "Mute", false);
+    m_main_volume = m_config->read_num_entry("Master", "Volume", 100);
+
     m_sound_thread->start();
 }
 
@@ -119,6 +127,10 @@ void Mixer::set_main_volume(int volume)
         m_main_volume = 200;
     else
         m_main_volume = volume;
+
+    m_config->write_num_entry("Master", "Volume", volume);
+    request_setting_sync();
+
     ClientConnection::for_each([&](ClientConnection& client) {
         client.did_change_main_mix_volume({}, m_main_volume);
     });
@@ -129,11 +141,28 @@ void Mixer::set_muted(bool muted)
     if (m_muted == muted)
         return;
     m_muted = muted;
+
+    m_config->write_bool_entry("Master", "Mute", m_muted);
+    request_setting_sync();
+
     ClientConnection::for_each([muted](ClientConnection& client) {
         client.did_change_muted_state({}, muted);
     });
 }
 
+void Mixer::request_setting_sync()
+{
+    if (m_config_write_timer.is_null() || !m_config_write_timer->is_active()) {
+        m_config_write_timer = Core::Timer::create_single_shot(
+            AUDIO_CONFIG_WRITE_INTERVAL,
+            [this] {
+                m_config->sync();
+            },
+            this);
+        m_config_write_timer->start();
+    }
+}
+
 BufferQueue::BufferQueue(ClientConnection& client)
     : m_client(client)
 {

Userland/Services/AudioServer/Mixer.h

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2021, kleines Filmröllchen <malu.bertsch@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -16,6 +17,7 @@
 #include <AK/WeakPtr.h>
 #include <LibAudio/Buffer.h>
 #include <LibCore/File.h>
+#include <LibCore/Timer.h>
 #include <LibThreading/Mutex.h>
 #include <LibThreading/Thread.h>
 
@@ -93,7 +95,7 @@ private:
 class Mixer : public Core::Object {
     C_OBJECT(Mixer)
 public:
-    Mixer();
+    Mixer(NonnullRefPtr<Core::ConfigFile> config);
     virtual ~Mixer() override;
 
     NonnullRefPtr<BufferQueue> create_queue(ClientConnection&);
@@ -105,6 +107,8 @@ public:
     void set_muted(bool);
 
 private:
+    void request_setting_sync();
+
     Vector<NonnullRefPtr<BufferQueue>> m_pending_mixing;
     Atomic<bool> m_added_queue { false };
     pthread_mutex_t m_pending_mutex;
@@ -117,8 +121,15 @@ private:
     bool m_muted { false };
     int m_main_volume { 100 };
 
+    NonnullRefPtr<Core::ConfigFile> m_config;
+    RefPtr<Core::Timer> m_config_write_timer;
+
     static u8 m_zero_filled_buffer[4096];
 
     void mix();
 };
+
+// Interval in ms when the server tries to save its configuration to disk.
+constexpr unsigned AUDIO_CONFIG_WRITE_INTERVAL = 2000;
+
 }

Userland/Services/AudioServer/main.cpp

@@ -1,10 +1,13 @@
 /*
  * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2021, kleines Filmröllchen <malu.bertsch@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #include "Mixer.h"
+#include <LibCore/ConfigFile.h>
+#include <LibCore/File.h>
 #include <LibCore/LocalServer.h>
 
 int main(int, char**)
@@ -14,8 +17,19 @@ int main(int, char**)
         return 1;
     }
 
+    auto config = Core::ConfigFile::get_for_app("Audio");
+    if (unveil(config->filename().characters(), "rwc") < 0) {
+        perror("unveil");
+        return 1;
+    }
+    if (unveil("/dev/audio", "wc") < 0) {
+        perror("unveil");
+        return 1;
+    }
+    unveil(nullptr, nullptr);
+
     Core::EventLoop event_loop;
-    AudioServer::Mixer mixer;
+    AudioServer::Mixer mixer { config };
 
     auto server = Core::LocalServer::construct();
     bool ok = server->take_over_from_system_server();
@@ -31,7 +45,7 @@ int main(int, char**)
         IPC::new_client_connection<AudioServer::ClientConnection>(client_socket.release_nonnull(), client_id, mixer);
     };
 
-    if (pledge("stdio recvfd thread accept", nullptr) < 0) {
+    if (pledge("stdio recvfd thread accept cpath rpath wpath", nullptr) < 0) {
         perror("pledge");
         return 1;
     }