WindowServer: Port threading to LibThread

Author: https://github.com/bugaevc
Commit: https://github.com/SerenityOS/serenity/commit/8d59b100225
Pull-request: https://github.com/SerenityOS/serenity/pull/486
Reviewed-by: https://github.com/awesomekling

Servers/WindowServer/Makefile

@@ -26,7 +26,7 @@ DEFINES += -DUSERLAND
 all: $(APP)
 
 $(APP): $(OBJS)
-	$(LD) -o $(APP) $(LDFLAGS) $(OBJS) -lc -lcore -ldraw
+	$(LD) -o $(APP) $(LDFLAGS) $(OBJS) -lc -lcore -ldraw -lthread
 
 .cpp.o:
 	@echo "CXX $<"; $(CXX) $(CXXFLAGS) -o $@ -c $<

Servers/WindowServer/WSCPUMonitor.cpp

@@ -9,26 +9,31 @@
 #include <unistd.h>
 
 WSCPUMonitor::WSCPUMonitor()
+    : m_thread([this] {
+        monitor();
+        return 0;
+    })
 {
-    create_thread([](void* context) -> int {
-        auto& monitor = *(WSCPUMonitor*)context;
-        for (;;) {
-            static unsigned last_busy;
-            static unsigned last_idle;
-            unsigned busy;
-            unsigned idle;
-            monitor.get_cpu_usage(busy, idle);
-            unsigned busy_diff = busy - last_busy;
-            unsigned idle_diff = idle - last_idle;
-            last_busy = busy;
-            last_idle = idle;
-            float cpu = (float)busy_diff / (float)(busy_diff + idle_diff);
-            monitor.m_cpu_history.enqueue(cpu);
-            monitor.m_dirty = true;
-            sleep(1);
-        }
-    },
-        this);
+    m_thread.start();
+}
+
+void WSCPUMonitor::monitor()
+{
+    for (;;) {
+        static unsigned last_busy;
+        static unsigned last_idle;
+        unsigned busy;
+        unsigned idle;
+        get_cpu_usage(busy, idle);
+        unsigned busy_diff = busy - last_busy;
+        unsigned idle_diff = idle - last_idle;
+        last_busy = busy;
+        last_idle = idle;
+        float cpu = (float)busy_diff / (float)(busy_diff + idle_diff);
+        m_cpu_history.enqueue(cpu);
+        m_dirty = true;
+        sleep(1);
+    }
 }
 
 void WSCPUMonitor::get_cpu_usage(unsigned& busy, unsigned& idle)

Servers/WindowServer/WSCPUMonitor.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <AK/CircularQueue.h>
+#include <LibThread/Thread.h>
 #include <stdio.h>
 
 class Painter;
@@ -16,8 +17,11 @@ public:
     void paint(Painter&, const Rect&);
 
 private:
+    void monitor();
+
     void get_cpu_usage(unsigned& busy, unsigned& idle);
 
     CircularQueue<float, 30> m_cpu_history;
     bool m_dirty { false };
+    LibThread::Thread m_thread;
 };

Servers/WindowServer/WSCompositor.cpp

@@ -7,6 +7,7 @@
 #include <LibDraw/Font.h>
 #include <LibDraw/PNGLoader.h>
 #include <LibDraw/Painter.h>
+#include <LibThread/BackgroundAction.h>
 
 // #define COMPOSITOR_DEBUG
 
@@ -265,43 +266,24 @@ void WSCompositor::invalidate(const Rect& a_rect)
 
 bool WSCompositor::set_wallpaper(const String& path, Function<void(bool)>&& callback)
 {
-    struct Context {
-        String path;
-        RefPtr<GraphicsBitmap> bitmap;
-        Function<void(bool)> callback;
-    };
-    auto context = make<Context>();
-    context->path = path;
-    context->callback = move(callback);
+    LibThread::BackgroundAction<RefPtr<GraphicsBitmap>>::create(
+        [path] {
+            return load_png(path);
+        },
 
-    int rc = create_thread([](void* ctx) -> int {
-        OwnPtr<Context> context((Context*)ctx);
-        context->bitmap = load_png(context->path);
-        if (!context->bitmap) {
-            context->callback(false);
-            exit_thread(0);
-            return 0;
-        }
-        the().deferred_invoke([context = move(context)](auto&) {
-            the().finish_setting_wallpaper(context->path, *context->bitmap);
-            context->callback(true);
+        [this, path, callback = move(callback)](RefPtr<GraphicsBitmap> bitmap) {
+            if (!bitmap) {
+                callback(false);
+                return;
+            }
+            m_wallpaper_path = path;
+            m_wallpaper = move(bitmap);
+            invalidate();
+            callback(true);
         });
-        exit_thread(0);
-        return 0;
-    },
-        context.leak_ptr());
-    ASSERT(rc > 0);
-
     return true;
 }
 
-void WSCompositor::finish_setting_wallpaper(const String& path, NonnullRefPtr<GraphicsBitmap>&& bitmap)
-{
-    m_wallpaper_path = path;
-    m_wallpaper = move(bitmap);
-    invalidate();
-}
-
 void WSCompositor::flip_buffers()
 {
     ASSERT(m_screen_can_set_buffer);

Servers/WindowServer/WSCompositor.h

@@ -43,7 +43,6 @@ private:
     void draw_cursor();
     void draw_geometry_label();
     void draw_menubar();
-    void finish_setting_wallpaper(const String& path, NonnullRefPtr<GraphicsBitmap>&&);
 
     unsigned m_compose_count { 0 };
     unsigned m_flush_count { 0 };