xcb,xlib: Cleanup GC cache handling

Device mutexes guarantee the consistency between multiple threads,
hence GC cache does not rely anymore on atomic operations.

This makes it possible to avoid bit twiddling and to use a simple
array.

4 files changed, 23 insertions, 19 deletions

diff --git a/src/cairo-xcb-private.h b/src/cairo-xcb-private.h
index 2897b07a..a80ed14b 100644
--- a/src/cairo-xcb-private.h
+++ b/src/cairo-xcb-private.h
@@ -56,6 +56,9 @@
 #include <xcb/xcbext.h>
 #include <pixman.h>
 
+/* maximum number of cached GC's */
+#define GC_CACHE_SIZE 4
+
 #define CAIRO_XCB_RENDER_AT_LEAST(major, minor)	\
 	((XCB_RENDER_MAJOR_VERSION > major) ||	\
 	((XCB_RENDER_MAJOR_VERSION == major) && (XCB_RENDER_MINOR_VERSION >= minor)))
@@ -172,8 +175,8 @@ struct _cairo_xcb_screen {
 
     xcb_screen_t	    *xcb_screen;
 
-    xcb_gcontext_t gc[4];
-    int gc_depths; /* 4 x uint8_t */
+    xcb_gcontext_t gc[GC_CACHE_SIZE];
+    uint8_t gc_depths[GC_CACHE_SIZE];
 
     cairo_surface_t *stock_colors[CAIRO_STOCK_NUM_COLORS];
     struct {
diff --git a/src/cairo-xcb-screen.c b/src/cairo-xcb-screen.c
index a7802c2d..7b5493f1 100644
--- a/src/cairo-xcb-screen.c
+++ b/src/cairo-xcb-screen.c
@@ -81,7 +81,7 @@ _cairo_xcb_screen_finish (cairo_xcb_screen_t *screen)
 	cairo_surface_destroy (screen->stock_colors[i]);
 
     for (i = 0; i < ARRAY_LENGTH (screen->gc); i++) {
-	if (((screen->gc_depths >> (8*i)) & 0xff) != 0)
+	if (screen->gc_depths[i] != 0)
 	    _cairo_xcb_connection_free_gc (screen->connection, screen->gc[i]);
     }
 
@@ -168,7 +168,7 @@ _cairo_xcb_screen_get (xcb_connection_t *xcb_connection,
     cairo_list_init (&screen->surfaces);
     cairo_list_init (&screen->pictures);
 
-    screen->gc_depths = 0;
+    memset (screen->gc_depths, 0, sizeof (screen->gc_depths));
     memset (screen->gc, 0, sizeof (screen->gc));
 
     screen->solid_cache_size = 0;
@@ -228,8 +228,8 @@ _cairo_xcb_screen_get_gc (cairo_xcb_screen_t *screen,
     assert (CAIRO_MUTEX_IS_LOCKED (screen->connection->device.mutex));
 
     for (i = 0; i < ARRAY_LENGTH (screen->gc); i++) {
-	if (((screen->gc_depths >> (8*i)) & 0xff) == depth) {
-	    screen->gc_depths &= ~(0xff << (8*i));
+	if (screen->gc_depths[i] == depth) {
+	    screen->gc_depths[i] = 0;
 	    return screen->gc[i];
 	}
     }
@@ -245,7 +245,7 @@ _cairo_xcb_screen_put_gc (cairo_xcb_screen_t *screen, int depth, xcb_gcontext_t
     assert (CAIRO_MUTEX_IS_LOCKED (screen->connection->device.mutex));
 
     for (i = 0; i < ARRAY_LENGTH (screen->gc); i++) {
-	if (((screen->gc_depths >> (8*i)) & 0xff) == 0)
+	if (screen->gc_depths[i] == 0)
 	    break;
     }
 
@@ -256,8 +256,7 @@ _cairo_xcb_screen_put_gc (cairo_xcb_screen_t *screen, int depth, xcb_gcontext_t
     }
 
     screen->gc[i] = gc;
-    screen->gc_depths &= ~(0xff << (8*i));
-    screen->gc_depths |= depth << (8*i);
+    screen->gc_depths[i] = depth;
 }
 
 cairo_status_t
diff --git a/src/cairo-xlib-private.h b/src/cairo-xlib-private.h
index a6bdcd1e..d10e986d 100644
--- a/src/cairo-xlib-private.h
+++ b/src/cairo-xlib-private.h
@@ -66,6 +66,8 @@ struct _cairo_xlib_hook {
 #define CUBE_SIZE 6
 /* size of gray ramp */
 #define RAMP_SIZE 16
+/* maximum number of cached GC's */
+#define GC_CACHE_SIZE 4
 
 struct _cairo_xlib_display {
     cairo_device_t base;
@@ -110,8 +112,8 @@ struct _cairo_xlib_screen {
     cairo_bool_t has_font_options;
     cairo_font_options_t font_options;
 
-    GC gc[4];
-    cairo_atomic_int_t gc_depths; /* 4 x uint8_t */
+    GC gc[GC_CACHE_SIZE];
+    uint8_t gc_depths[GC_CACHE_SIZE];
 
     cairo_list_t visuals;
 };
diff --git a/src/cairo-xlib-screen.c b/src/cairo-xlib-screen.c
index 8ac99351..dc060c2e 100644
--- a/src/cairo-xlib-screen.c
+++ b/src/cairo-xlib-screen.c
@@ -278,10 +278,11 @@ _cairo_xlib_screen_close_display (cairo_xlib_display_t *display,
     dpy = display->display;
 
     for (i = 0; i < ARRAY_LENGTH (info->gc); i++) {
-	if ((info->gc_depths >> (8*i)) & 0xff)
+	if (info->gc_depths[i] != 0) {
 	    XFreeGC (dpy, info->gc[i]);
+	    info->gc_depths[i] = 0;
+	}
     }
-    info->gc_depths = 0;
 }
 
 void
@@ -332,7 +333,7 @@ _cairo_xlib_screen_get (Display *dpy,
     info->device = device;
     info->screen = screen;
     info->has_font_options = FALSE;
-    info->gc_depths = 0;
+    memset (info->gc_depths, 0, sizeof (info->gc_depths));
     memset (info->gc, 0, sizeof (info->gc));
 
     cairo_list_init (&info->visuals);
@@ -358,8 +359,8 @@ _cairo_xlib_screen_get_gc (cairo_xlib_display_t *display,
     int i;
 
     for (i = 0; i < ARRAY_LENGTH (info->gc); i++) {
-	if (((info->gc_depths >> (8*i)) & 0xff) == depth) {
-	    info->gc_depths &= ~(0xff << (8*i));
+	if (info->gc_depths[i] == depth) {
+	    info->gc_depths[i] = 0;
 	    gc = info->gc[i];
 	    break;
 	}
@@ -387,7 +388,7 @@ _cairo_xlib_screen_put_gc (cairo_xlib_display_t *display,
     int i;
 
     for (i = 0; i < ARRAY_LENGTH (info->gc); i++) {
-	if (((info->gc_depths >> (8*i)) & 0xff) == 0)
+	if (info->gc_depths[i] == 0)
 	    break;
     }
 
@@ -408,8 +409,7 @@ _cairo_xlib_screen_put_gc (cairo_xlib_display_t *display,
     }
 
     info->gc[i] = gc;
-    info->gc_depths &= ~(0xff << (8*i));
-    info->gc_depths |= depth << (8*i);
+    info->gc_depths[i] = depth;
 }
 
 cairo_status_t