WindowServer: Move the CPU monitor thingy to its own class.

Servers/WindowServer/WSCPUMonitor.cpp

@@ -0,0 +1,74 @@
+#include <WindowServer/WSCPUMonitor.h>
+#include <WindowServer/WSMessageLoop.h>
+#include <WindowServer/WSWindowManager.h>
+#include <unistd.h>
+#include <stdio.h>
+
+WSCPUMonitor::WSCPUMonitor()
+{
+    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);
+}
+
+void WSCPUMonitor::get_cpu_usage(unsigned& busy, unsigned& idle)
+{
+    busy = 0;
+    idle = 0;
+
+    FILE* fp = fopen("/proc/all", "r");
+    if (!fp) {
+        perror("failed to open /proc/all");
+        ASSERT_NOT_REACHED();
+    }
+    for (;;) {
+        char buf[BUFSIZ];
+        char* ptr = fgets(buf, sizeof(buf), fp);
+        if (!ptr)
+            break;
+        auto parts = String(buf, Chomp).split(',');
+        if (parts.size() < 17)
+            break;
+        bool ok;
+        pid_t pid = parts[0].to_uint(ok);
+        ASSERT(ok);
+        unsigned nsched = parts[1].to_uint(ok);
+        ASSERT(ok);
+
+        if (pid == 0)
+            idle += nsched;
+        else
+            busy += nsched;
+    }
+    int rc = fclose(fp);
+    ASSERT(rc == 0);
+}
+
+void WSCPUMonitor::paint(Painter& painter, const Rect& rect)
+{
+    painter.fill_rect(rect, Color::Black);
+    int i = m_cpu_history.capacity() - m_cpu_history.size();
+    for (auto cpu_usage : m_cpu_history) {
+        painter.draw_line(
+            { rect.x() + i, rect.bottom() },
+            { rect.x() + i, (int)(rect.y() + (rect.height() - (cpu_usage * (float)rect.height()))) },
+            Color::from_rgb(0xaa6d4b)
+        );
+        ++i;
+    }
+}