[analysis] Merge two analysis status codes.

Since there is an implicit precedence in the ranking of the analysis
return codes, provide a function to centralize the logic within the
analysis surface and isolate the backends from the complexity.

src/cairo-analysis-surface-private.h

@@ -66,6 +66,9 @@ cairo_private void
 _cairo_analysis_surface_get_bounding_box (cairo_surface_t *surface,
 					  cairo_box_t     *bbox);
 
+cairo_private cairo_int_status_t
+_cairo_analysis_surface_merge_status (cairo_int_status_t status_a,
+				      cairo_int_status_t status_b);
 
 cairo_private cairo_surface_t *
 _cairo_null_surface_create (cairo_content_t content);

src/cairo-analysis-surface.c

@@ -62,6 +62,38 @@ typedef struct {
 
 } cairo_analysis_surface_t;
 
+cairo_int_status_t
+_cairo_analysis_surface_merge_status (cairo_int_status_t status_a,
+				      cairo_int_status_t status_b)
+{
+    /* fatal errors should be checked and propagated at source */
+    assert (! _cairo_status_is_error (status_a));
+    assert (! _cairo_status_is_error (status_b));
+
+    /* return the most important status */
+    if (status_a == CAIRO_INT_STATUS_UNSUPPORTED ||
+	status_b == CAIRO_INT_STATUS_UNSUPPORTED)
+	return CAIRO_INT_STATUS_UNSUPPORTED;
+
+    if (status_a == CAIRO_INT_STATUS_IMAGE_FALLBACK ||
+	status_b == CAIRO_INT_STATUS_IMAGE_FALLBACK)
+	return CAIRO_INT_STATUS_IMAGE_FALLBACK;
+
+    if (status_a == CAIRO_INT_STATUS_ANALYZE_META_SURFACE_PATTERN ||
+	status_b == CAIRO_INT_STATUS_ANALYZE_META_SURFACE_PATTERN)
+	return CAIRO_INT_STATUS_ANALYZE_META_SURFACE_PATTERN;
+
+    if (status_a == CAIRO_INT_STATUS_FLATTEN_TRANSPARENCY ||
+	status_b == CAIRO_INT_STATUS_FLATTEN_TRANSPARENCY)
+	return CAIRO_INT_STATUS_FLATTEN_TRANSPARENCY;
+
+    /* at this point we have checked all the valid internal codes, so... */
+    assert (status_a == CAIRO_STATUS_SUCCESS &&
+	    status_b == CAIRO_STATUS_SUCCESS);
+
+    return CAIRO_STATUS_SUCCESS;
+}
+
 static cairo_int_status_t
 _analyze_meta_surface_pattern (cairo_analysis_surface_t	*surface,
 			       cairo_pattern_t		*pattern)
@@ -349,8 +381,7 @@ _cairo_analysis_surface_mask (void		*abstract_surface,
 	    if (_cairo_surface_is_meta (surface_pattern->surface)) {
 		backend_source_status =
 		    _analyze_meta_surface_pattern (surface, source);
-		if (backend_source_status != CAIRO_STATUS_SUCCESS &&
-		    backend_source_status != CAIRO_INT_STATUS_IMAGE_FALLBACK)
+		if (_cairo_status_is_error (backend_source_status))
 		    return backend_source_status;
 	    }
 	}
@@ -360,19 +391,14 @@ _cairo_analysis_surface_mask (void		*abstract_surface,
 	    if (_cairo_surface_is_meta (surface_pattern->surface)) {
 		backend_mask_status =
 		    _analyze_meta_surface_pattern (surface, mask);
-		if (backend_mask_status != CAIRO_STATUS_SUCCESS &&
-		    backend_mask_status != CAIRO_INT_STATUS_IMAGE_FALLBACK)
-		    return backend_status;
+		if (_cairo_status_is_error (backend_mask_status))
+		    return backend_mask_status;
 	    }
 	}
 
-	backend_status = CAIRO_STATUS_SUCCESS;
-
-	if (backend_source_status == CAIRO_INT_STATUS_IMAGE_FALLBACK ||
-	    backend_mask_status == CAIRO_INT_STATUS_IMAGE_FALLBACK)
-	{
-	    backend_status = CAIRO_INT_STATUS_IMAGE_FALLBACK;
-	}
+	backend_status =
+	    _cairo_analysis_surface_merge_status (backend_source_status,
+						  backend_mask_status);
     }
 
     status = _cairo_surface_get_extents (&surface->base, &extents);

src/cairo-pdf-surface.c

@@ -44,10 +44,11 @@
 #include "cairo-pdf.h"
 #include "cairo-pdf-surface-private.h"
 #include "cairo-pdf-operators-private.h"
-#include "cairo-scaled-font-subsets-private.h"
-#include "cairo-paginated-private.h"
-#include "cairo-output-stream-private.h"
+#include "cairo-analysis-surface-private.h"
 #include "cairo-meta-surface-private.h"
+#include "cairo-output-stream-private.h"
+#include "cairo-paginated-private.h"
+#include "cairo-scaled-font-subsets-private.h"
 #include "cairo-type3-glyph-surface-private.h"
 
 #include <time.h>
@@ -4475,30 +4476,16 @@ _cairo_pdf_surface_mask	(void			*abstract_surface,
     if (surface->paginated_mode == CAIRO_PAGINATED_MODE_ANALYZE) {
 	cairo_status_t source_status, mask_status;
 
-	source_status =  _cairo_pdf_surface_analyze_operation (surface, op, source);
-	if (source_status != CAIRO_STATUS_SUCCESS &&
-	    source_status < CAIRO_INT_STATUS_UNSUPPORTED)
+	source_status = _cairo_pdf_surface_analyze_operation (surface, op, source);
+	if (_cairo_status_is_error (source_status))
 	    return source_status;
 
 	mask_status = _cairo_pdf_surface_analyze_operation (surface, op, mask);
-	if (mask_status != CAIRO_STATUS_SUCCESS &&
-	    mask_status < CAIRO_INT_STATUS_UNSUPPORTED)
+	if (_cairo_status_is_error (mask_status))
 	    return mask_status;
 
-	/* return the most important status from either the source or mask */
-	if (source_status == CAIRO_INT_STATUS_UNSUPPORTED ||
-	    mask_status == CAIRO_INT_STATUS_UNSUPPORTED)
-	    return CAIRO_INT_STATUS_UNSUPPORTED;
-
-	if (source_status == CAIRO_INT_STATUS_IMAGE_FALLBACK ||
-	    mask_status == CAIRO_INT_STATUS_IMAGE_FALLBACK)
-	    return CAIRO_INT_STATUS_IMAGE_FALLBACK;
-
-	if (source_status == CAIRO_INT_STATUS_ANALYZE_META_SURFACE_PATTERN ||
-	    mask_status == CAIRO_INT_STATUS_ANALYZE_META_SURFACE_PATTERN)
-	    return CAIRO_INT_STATUS_ANALYZE_META_SURFACE_PATTERN;
-
-	return CAIRO_STATUS_SUCCESS;
+	return _cairo_analysis_surface_merge_status (source_status,
+						     mask_status);
     } else if (surface->paginated_mode == CAIRO_PAGINATED_MODE_FALLBACK) {
 	status = _cairo_pdf_surface_start_fallback (surface);
 	if (status)