Pacify --enable-gcc-warnings --with-cairo

Problem reported by Alexander Kuleshov in:
http://lists.gnu.org/archive/html/emacs-devel/2016-01/msg01289.html
* src/gtkutil.c (xg_get_page_setup):
Use switch rather than if-then-else.
* src/image.c (COLOR_TABLE_SUPPORT):
Define directly rather than via #define and optional later #undef.
(lookup_rgb_color) [USE_CAIRO && ENABLE_CHECKING]:
Crash when the pixel is undefined, as there is a genuine bug
here (Bug#22442).
* src/image.c (tiff_load, gif_load, svg_load_image)
(x_kill_gs_process) [USE_CAIRO]:
* src/xterm.c (x_draw_fringe_bitmap) [USE_CAIRO]:
Omit unused locals, or move them to where they’re needed.
(x_clear_area1): Now ATTRIBUTE_UNUSED.

3 files changed, 47 insertions, 52 deletions

diff --git a/src/gtkutil.c b/src/gtkutil.c
index 768df34298..14b76ce67a 100644
--- a/src/gtkutil.c
+++ b/src/gtkutil.c
@@ -4084,20 +4084,28 @@ xg_page_setup_dialog (void)
 Lisp_Object
 xg_get_page_setup (void)
 {
-  GtkPageOrientation orientation;
   Lisp_Object orientation_symbol;
 
   if (page_setup == NULL)
     page_setup = gtk_page_setup_new ();
-  orientation = gtk_page_setup_get_orientation (page_setup);
-  if (orientation == GTK_PAGE_ORIENTATION_PORTRAIT)
-    orientation_symbol = Qportrait;
-  else if (orientation == GTK_PAGE_ORIENTATION_LANDSCAPE)
-    orientation_symbol = Qlandscape;
-  else if (orientation == GTK_PAGE_ORIENTATION_REVERSE_PORTRAIT)
-    orientation_symbol = Qreverse_portrait;
-  else if (orientation == GTK_PAGE_ORIENTATION_REVERSE_LANDSCAPE)
-    orientation_symbol = Qreverse_landscape;
+
+  switch (gtk_page_setup_get_orientation (page_setup))
+    {
+    case GTK_PAGE_ORIENTATION_PORTRAIT:
+      orientation_symbol = Qportrait;
+      break;
+    case GTK_PAGE_ORIENTATION_LANDSCAPE:
+      orientation_symbol = Qlandscape;
+      break;
+    case GTK_PAGE_ORIENTATION_REVERSE_PORTRAIT:
+      orientation_symbol = Qreverse_portrait;
+      break;
+    case GTK_PAGE_ORIENTATION_REVERSE_LANDSCAPE:
+      orientation_symbol = Qreverse_landscape;
+      break;
+    default:
+      eassume (false);
+    }
 
   return listn (CONSTYPE_HEAP, 7,
 		Fcons (Qorientation, orientation_symbol),
diff --git a/src/image.c b/src/image.c
index 8bb5ff77b2..4681cba1f8 100644
--- a/src/image.c
+++ b/src/image.c
@@ -57,8 +57,6 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #endif /* HAVE_WINDOW_SYSTEM */
 
 #ifdef HAVE_X_WINDOWS
-#define COLOR_TABLE_SUPPORT 1
-
 typedef struct x_bitmap_record Bitmap_Record;
 #define GET_PIXEL(ximg, x, y) XGetPixel (ximg, x, y)
 #define NO_PIXMAP None
@@ -74,9 +72,6 @@ typedef struct x_bitmap_record Bitmap_Record;
 # include "w32.h"
 #endif
 
-/* W32_TODO : Color tables on W32.  */
-#undef COLOR_TABLE_SUPPORT
-
 typedef struct w32_bitmap_record Bitmap_Record;
 #define GET_PIXEL(ximg, x, y) GetPixel (ximg, x, y)
 #define NO_PIXMAP 0
@@ -89,13 +84,7 @@ typedef struct w32_bitmap_record Bitmap_Record;
 
 #endif /* HAVE_NTGUI */
 
-#ifdef USE_CAIRO
-#undef COLOR_TABLE_SUPPORT
-#endif
-
 #ifdef HAVE_NS
-#undef COLOR_TABLE_SUPPORT
-
 typedef struct ns_bitmap_record Bitmap_Record;
 
 #define GET_PIXEL(ximg, x, y) XGetPixel (ximg, x, y)
@@ -109,6 +98,12 @@ typedef struct ns_bitmap_record Bitmap_Record;
 #define DefaultDepthOfScreen(screen) x_display_list->n_planes
 #endif /* HAVE_NS */
 
+#if (defined HAVE_X_WINDOWS \
+     && ! (defined HAVE_NTGUI || defined USE_CAIRO || defined HAVE_NS))
+/* W32_TODO : Color tables on W32.  */
+# define COLOR_TABLE_SUPPORT 1
+#endif
+
 static void x_disable_image (struct frame *, struct image *);
 static void x_edge_detection (struct frame *, struct image *, Lisp_Object,
                               Lisp_Object);
@@ -4615,16 +4610,13 @@ colors_in_color_table (int *n)
 static unsigned long
 lookup_rgb_color (struct frame *f, int r, int g, int b)
 {
-  unsigned long pixel;
-
 #ifdef HAVE_NTGUI
-  pixel = PALETTERGB (r >> 8, g >> 8, b >> 8);
-#endif /* HAVE_NTGUI */
-
-#ifdef HAVE_NS
-  pixel = RGB_TO_ULONG (r >> 8, g >> 8, b >> 8);
-#endif /* HAVE_NS */
-  return pixel;
+  return PALETTERGB (r >> 8, g >> 8, b >> 8);
+#elif defined HAVE_NS
+  return RGB_TO_ULONG (r >> 8, g >> 8, b >> 8);
+#else
+  eassume (false);
+#endif
 }
 
 static void
@@ -7320,7 +7312,6 @@ tiff_load (struct frame *f, struct image *img)
   {
     unsigned char *data = (unsigned char *) xmalloc (width*height*4);
     uint32_t *dataptr = (uint32_t *) data;
-    int r, g, b, a;
 
     for (y = 0; y < height; ++y)
       {
@@ -7634,19 +7625,19 @@ gif_load (struct frame *f, struct image *img)
 {
   int rc, width, height, x, y, i, j;
   ColorMapObject *gif_color_map;
-  unsigned long pixel_colors[256];
   GifFileType *gif;
   gif_memory_source memsrc;
   Lisp_Object specified_bg = image_spec_value (img->spec, QCbackground, NULL);
   Lisp_Object specified_file = image_spec_value (img->spec, QCfile, NULL);
   Lisp_Object specified_data = image_spec_value (img->spec, QCdata, NULL);
-  unsigned long bgcolor = 0;
   EMACS_INT idx;
   int gif_err;
 
 #ifdef USE_CAIRO
   unsigned char *data = 0;
 #else
+  unsigned long pixel_colors[256];
+  unsigned long bgcolor = 0;
   XImagePtr ximg;
 #endif
 
@@ -7833,9 +7824,13 @@ gif_load (struct frame *f, struct image *img)
      gif_load call to construct and save all animation frames.  */
 
   init_color_table ();
+
+#ifndef USE_CAIRO
   if (STRINGP (specified_bg))
     bgcolor = x_alloc_image_color (f, img, specified_bg,
 				   FRAME_BACKGROUND_PIXEL (f));
+#endif
+
   for (j = 0; j <= idx; ++j)
     {
       /* We use a local variable `raster' here because RasterBits is a
@@ -9182,11 +9177,6 @@ svg_load_image (struct frame *f,         /* Pointer to emacs frame structure.  *
   int height;
   const guint8 *pixels;
   int rowstride;
-  XImagePtr ximg;
-  Lisp_Object specified_bg;
-  XColor background;
-  int x;
-  int y;
 
 #if ! GLIB_CHECK_VERSION (2, 36, 0)
   /* g_type_init is a glib function that must be called prior to
@@ -9240,16 +9230,14 @@ svg_load_image (struct frame *f,         /* Pointer to emacs frame structure.  *
 #ifdef USE_CAIRO
   {
     unsigned char *data = (unsigned char *) xmalloc (width*height*4);
-    int y;
     uint32_t bgcolor = get_spec_bg_or_alpha_as_argb (img, f);
 
-    for (y = 0; y < height; ++y)
+    for (int y = 0; y < height; ++y)
       {
         const guchar *iconptr = pixels + y * rowstride;
         uint32_t *dataptr = (uint32_t *) (data + y * rowstride);
-        int x;
 
-        for (x = 0; x < width; ++x)
+        for (int x = 0; x < width; ++x)
           {
             if (iconptr[3] == 0)
               *dataptr = bgcolor;
@@ -9269,6 +9257,7 @@ svg_load_image (struct frame *f,         /* Pointer to emacs frame structure.  *
   }
 #else
   /* Try to create a x pixmap to hold the svg pixmap.  */
+  XImagePtr ximg;
   if (!image_create_x_image_and_pixmap (f, img, width, height, 0, &ximg, 0))
     {
       g_object_unref (pixbuf);
@@ -9279,7 +9268,8 @@ svg_load_image (struct frame *f,         /* Pointer to emacs frame structure.  *
 
   /* Handle alpha channel by combining the image with a background
      color.  */
-  specified_bg = image_spec_value (img->spec, QCbackground, NULL);
+  XColor background;
+  Lisp_Object specified_bg = image_spec_value (img->spec, QCbackground, NULL);
   if (!STRINGP (specified_bg)
       || !x_defined_color (f, SSDATA (specified_bg), &background, 0))
     x_query_frame_background_color (f, &background);
@@ -9295,9 +9285,9 @@ svg_load_image (struct frame *f,         /* Pointer to emacs frame structure.  *
      non-transparent images.  Each pixel must be "flattened" by
      calculating the resulting color, given the transparency of the
      pixel, and the image background color.  */
-  for (y = 0; y < height; ++y)
+  for (int y = 0; y < height; ++y)
     {
-      for (x = 0; x < width; ++x)
+      for (int x = 0; x < width; ++x)
 	{
 	  int red;
 	  int green;
@@ -9597,8 +9587,6 @@ x_kill_gs_process (Pixmap pixmap, struct frame *f)
 			0, 0, img->width, img->height, ~0, ZPixmap);
       if (ximg)
 	{
-	  int x, y;
-
 	  /* Initialize the color table.  */
 	  init_color_table ();
 
@@ -9606,8 +9594,8 @@ x_kill_gs_process (Pixmap pixmap, struct frame *f)
 	     color table.  After having done so, the color table will
 	     contain an entry for each color used by the image.  */
 #ifdef COLOR_TABLE_SUPPORT
-	  for (y = 0; y < img->height; ++y)
-	    for (x = 0; x < img->width; ++x)
+	  for (int y = 0; y < img->height; ++y)
+	    for (int x = 0; x < img->width; ++x)
 	      {
 		unsigned long pixel = XGetPixel (ximg, x, y);
 
diff --git a/src/xterm.c b/src/xterm.c
index 6a38d24c63..1f71afd7f7 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -1313,7 +1313,6 @@ x_draw_fringe_bitmap (struct window *w, struct glyph_row *row, struct draw_fring
 {
   struct frame *f = XFRAME (WINDOW_FRAME (w));
   Display *display = FRAME_X_DISPLAY (f);
-  Window window = FRAME_X_WINDOW (f);
   GC gc = f->output_data.x->normal_gc;
   struct face *face = p->face;
 
@@ -1356,6 +1355,7 @@ x_draw_fringe_bitmap (struct window *w, struct glyph_row *row, struct draw_fring
 #else  /* not USE_CAIRO */
   if (p->which)
     {
+      Window window = FRAME_X_WINDOW (f);
       char *bits;
       Pixmap pixmap, clipmask = (Pixmap) 0;
       int depth = DefaultDepthOfScreen (FRAME_X_SCREEN (f));
@@ -3758,7 +3758,7 @@ x_delete_glyphs (struct frame *f, register int n)
 /* Like XClearArea, but check that WIDTH and HEIGHT are reasonable.
    If they are <= 0, this is probably an error.  */
 
-static void
+static ATTRIBUTE_UNUSED void
 x_clear_area1 (Display *dpy, Window window,
                int x, int y, int width, int height, int exposures)
 {
@@ -3766,7 +3766,6 @@ x_clear_area1 (Display *dpy, Window window,
   XClearArea (dpy, window, x, y, width, height, exposures);
 }
 
-
 void
 x_clear_area (struct frame *f, int x, int y, int width, int height)
 {