ui/cocoa.m: add Speed menu

Programs running inside of QEMU can sometimes use more CPU time than is really
needed. To solve this problem, we just need to throttle the virtual CPU. This
feature will stop laptops from burning up.

This patch adds a menu called Speed that has menu items from 100% to 1% that
represent the speed options. 100% is full speed and 1% is slowest.

Signed-off-by: John Arbuckle <programmingkidx@gmail.com>
Message-id: D6FAAABF-064D-49C0-B572-C73679F34052@gmail.com
[PMM: Moved "mark 100% menu item as checked initially" code to
 after menu item is allocated, not before it]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

ui/cocoa.m

@@ -35,6 +35,7 @@
 #include "sysemu/blockdev.h"
 #include "qemu-version.h"
 #include <Carbon/Carbon.h>
+#include "qom/cpu.h"
 
 #ifndef MAC_OS_X_VERSION_10_5
 #define MAC_OS_X_VERSION_10_5 1050
@@ -893,6 +894,7 @@ QemuCocoaView *cocoaView;
 - (void)openDocumentation:(NSString *)filename;
 - (IBAction) do_about_menu_item: (id) sender;
 - (void)make_about_window;
+- (void)adjustSpeed:(id)sender;
 @end
 
 @implementation QemuCocoaAppController
@@ -1299,6 +1301,34 @@ QemuCocoaView *cocoaView;
     [superView addSubview: copyright_label];
 }
 
+/* Used by the Speed menu items */
+- (void)adjustSpeed:(id)sender
+{
+    int throttle_pct; /* throttle percentage */
+    NSMenu *menu;
+
+    menu = [sender menu];
+    if (menu != nil)
+    {
+        /* Unselect the currently selected item */
+        for (NSMenuItem *item in [menu itemArray]) {
+            if (item.state == NSOnState) {
+                [item setState: NSOffState];
+                break;
+            }
+        }
+    }
+
+    // check the menu item
+    [sender setState: NSOnState];
+
+    // get the throttle percentage
+    throttle_pct = [sender tag];
+
+    cpu_throttle_set(throttle_pct);
+    COCOA_DEBUG("cpu throttling at %d%c\n", cpu_throttle_get_percentage(), '%');
+}
+
 @end
 
 
@@ -1381,6 +1411,32 @@ int main (int argc, const char * argv[]) {
     [menuItem setSubmenu:menu];
     [[NSApp mainMenu] addItem:menuItem];
 
+    // Speed menu
+    menu = [[NSMenu alloc] initWithTitle:@"Speed"];
+
+    // Add the rest of the Speed menu items
+    int p, percentage, throttle_pct;
+    for (p = 10; p >= 0; p--)
+    {
+        percentage = p * 10 > 1 ? p * 10 : 1; // prevent a 0% menu item
+
+        menuItem = [[[NSMenuItem alloc]
+                   initWithTitle: [NSString stringWithFormat: @"%d%%", percentage] action:@selector(adjustSpeed:) keyEquivalent:@""] autorelease];
+
+        if (percentage == 100) {
+            [menuItem setState: NSOnState];
+        }
+
+        /* Calculate the throttle percentage */
+        throttle_pct = -1 * percentage + 100;
+
+        [menuItem setTag: throttle_pct];
+        [menu addItem: menuItem];
+    }
+    menuItem = [[[NSMenuItem alloc] initWithTitle:@"Speed" action:nil keyEquivalent:@""] autorelease];
+    [menuItem setSubmenu:menu];
+    [[NSApp mainMenu] addItem:menuItem];
+
     // Window menu
     menu = [[NSMenu alloc] initWithTitle:@"Window"];
     [menu addItem: [[[NSMenuItem alloc] initWithTitle:@"Minimize" action:@selector(performMiniaturize:) keyEquivalent:@"m"] autorelease]]; // Miniaturize