From c3029a6a1f51bd5876eabc8bc386dcca174fc9ab Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Thu, 5 Dec 2019 19:38:08 +0100
Subject: [PATCH] MenuApplets: Add CPUGraph, our first menu applet :^)

This implements the WSCPUMonitor functionality in a separate process.
---
 Kernel/build-root-filesystem.sh |  1 +
 Kernel/makeall.sh               |  2 +
 MenuApplets/CPUGraph/.gitignore |  1 +
 MenuApplets/CPUGraph/Makefile   |  7 +++
 MenuApplets/CPUGraph/main.cpp   | 87 +++++++++++++++++++++++++++++++++
 MenuApplets/Makefile.common     | 14 ++++++
 6 files changed, 112 insertions(+)
 create mode 100644 MenuApplets/CPUGraph/.gitignore
 create mode 100755 MenuApplets/CPUGraph/Makefile
 create mode 100644 MenuApplets/CPUGraph/main.cpp
 create mode 100755 MenuApplets/Makefile.common

diff --git a/Kernel/build-root-filesystem.sh b/Kernel/build-root-filesystem.sh
index 5618d2351a3..c513e10b429 100755
--- a/Kernel/build-root-filesystem.sh
+++ b/Kernel/build-root-filesystem.sh
@@ -108,6 +108,7 @@ cp ../Servers/TTYServer/TTYServer mnt/bin/TTYServer
 cp ../Servers/TelnetServer/TelnetServer mnt/bin/TelnetServer
 cp ../Servers/ProtocolServer/ProtocolServer mnt/bin/ProtocolServer
 cp ../Shell/Shell mnt/bin/Shell
+cp ../MenuApplets/CPUGraph/CPUGraph.MenuApplet mnt/bin/
 echo "done"
 
 printf "installing shortcuts... "
diff --git a/Kernel/makeall.sh b/Kernel/makeall.sh
index 6d6321a9790..309aafac437 100755
--- a/Kernel/makeall.sh
+++ b/Kernel/makeall.sh
@@ -92,6 +92,8 @@ build_targets="$build_targets ../Shell"
 
 build_targets="$build_targets ../Userland"
 
+build_targets="$build_targets ../MenuApplets/CPUGraph"
+
 build_targets="$build_targets ." # the kernel
 
 (cd ../AK/Tests && $make_cmd clean)
diff --git a/MenuApplets/CPUGraph/.gitignore b/MenuApplets/CPUGraph/.gitignore
new file mode 100644
index 00000000000..699bfb17aa5
--- /dev/null
+++ b/MenuApplets/CPUGraph/.gitignore
@@ -0,0 +1 @@
+CPUGraph.MenuApplet
diff --git a/MenuApplets/CPUGraph/Makefile b/MenuApplets/CPUGraph/Makefile
new file mode 100755
index 00000000000..b90b7103a53
--- /dev/null
+++ b/MenuApplets/CPUGraph/Makefile
@@ -0,0 +1,7 @@
+include ../../Makefile.common
+
+OBJS = main.o 
+
+APP = CPUGraph.MenuApplet
+
+include ../Makefile.common
diff --git a/MenuApplets/CPUGraph/main.cpp b/MenuApplets/CPUGraph/main.cpp
new file mode 100644
index 00000000000..8190c9aec00
--- /dev/null
+++ b/MenuApplets/CPUGraph/main.cpp
@@ -0,0 +1,87 @@
+#include <AK/CircularQueue.h>
+#include <LibCore/CProcessStatisticsReader.h>
+#include <LibCore/CTimer.h>
+#include <LibDraw/GraphicsBitmap.h>
+#include <LibGUI/GApplication.h>
+#include <LibGUI/GPainter.h>
+#include <LibGUI/GWindowServerConnection.h>
+
+NonnullRefPtr<GraphicsBitmap> create_shared_bitmap(const Size& size)
+{
+    ASSERT(GWindowServerConnection::the().server_pid());
+    ASSERT(!size.is_empty());
+    size_t pitch = round_up_to_power_of_two(size.width() * sizeof(RGBA32), 16);
+    size_t size_in_bytes = size.height() * pitch;
+    auto shared_buffer = SharedBuffer::create_with_size(size_in_bytes);
+    ASSERT(shared_buffer);
+    shared_buffer->share_with(GWindowServerConnection::the().server_pid());
+    return GraphicsBitmap::create_with_shared_buffer(GraphicsBitmap::Format::RGBA32, *shared_buffer, size);
+}
+
+static void get_cpu_usage(unsigned& busy, unsigned& idle)
+{
+    busy = 0;
+    idle = 0;
+
+    auto all_processes = CProcessStatisticsReader::get_all();
+
+    for (auto& it : all_processes) {
+        for (auto& jt : it.value.threads) {
+            if (it.value.pid == 0)
+                idle += jt.times_scheduled;
+            else
+                busy += jt.times_scheduled;
+        }
+    }
+}
+
+int main(int argc, char** argv)
+{
+    GApplication app(argc, argv);
+
+    Size applet_size(30, 16);
+    Rect applet_rect({}, applet_size);
+
+    CircularQueue<float, 30> cpu_history;
+
+    i32 applet_id = GWindowServerConnection::the().send_sync<WindowServer::CreateMenuApplet>(applet_size)->applet_id();
+    auto bitmap = create_shared_bitmap(applet_size);
+
+    GWindowServerConnection::the().send_sync<WindowServer::SetMenuAppletBackingStore>(applet_id, bitmap->shared_buffer_id());
+
+    unsigned last_busy = 0;
+    unsigned last_idle = 0;
+
+    auto repaint = [&] {
+        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);
+        cpu_history.enqueue(cpu);
+
+        GPainter painter(*bitmap);
+        painter.fill_rect(applet_rect, Color::Black);
+        int i = cpu_history.capacity() - cpu_history.size();
+        for (auto cpu_usage : cpu_history) {
+            painter.draw_line(
+                { applet_rect.x() + i, applet_rect.bottom() },
+                { applet_rect.x() + i, (int)(applet_rect.y() + (applet_rect.height() - (cpu_usage * (float)applet_rect.height()))) },
+                Color::from_rgb(0xaa6d4b));
+            ++i;
+        }
+
+        GWindowServerConnection::the().send_sync<WindowServer::InvalidateMenuAppletRect>(applet_id, applet_rect);
+    };
+
+    repaint();
+
+    auto timer = CTimer::construct(1000, [&] {
+        repaint();
+    });
+
+    return app.exec();
+}
diff --git a/MenuApplets/Makefile.common b/MenuApplets/Makefile.common
new file mode 100755
index 00000000000..23628b6a21e
--- /dev/null
+++ b/MenuApplets/Makefile.common
@@ -0,0 +1,14 @@
+DEFINES += -DUSERLAND
+
+all: $(APP)
+
+$(APP): $(OBJS)
+	$(LD) -o $(APP) $(LDFLAGS) $(OBJS) -laudio -lgui -lipc -ldraw -lthread -lpthread -lcore -lc
+
+.cpp.o:
+	@echo "CXX $<"; $(CXX) $(CXXFLAGS) -o $@ -c $<
+
+-include $(OBJS:%.o=%.d)
+
+clean:
+	@echo "CLEAN"; rm -f $(APP) $(OBJS) *.d