[test] Preparatory work for running under memfault.

In order to run under memfault, the framework is first extended to handle
running concurrent tests - i.e. multi-threading. (Not that this is a
requirement for memfault, instead it shares a common goal of storing
per-test data).  To that end all the global data is moved into a per-test
context and the targets are adjusted to avoid overlap on shared, global
resources (such as output files and frame buffers). In order to preserve
the simplicity of the standard draw routines, the context is not passed
explicitly as a parameter to the routines, but is instead attached to the
cairo_t via the user_data.

For the masochist, to enable the tests to be run across multiple threads
simply set the environment variable CAIRO_TEST_NUM_THREADS to the desired
number.

In the long run, we can hope the need for memfault (runtime testing of
error paths) will be mitigated by static analysis. A promising candidate
for this task would appear to be http://hal.cs.berkeley.edu/cil/.

1 files changed, 90 insertions, 32 deletions

diff --git a/test/buffer-diff.c b/test/buffer-diff.c
index d1b586376..ef708761c 100644
--- a/test/buffer-diff.c
+++ b/test/buffer-diff.c
@@ -47,12 +47,12 @@
 #define PERCEPTUAL_DIFF_THRESHOLD 25
 
 static void
-xunlink (const char *pathname)
+xunlink (const cairo_test_context_t *ctx, const char *pathname)
 {
     if (unlink (pathname) < 0 && errno != ENOENT) {
-	cairo_test_log ("  Error: Cannot remove %s: %s\n",
+	cairo_test_log (ctx, "  Error: Cannot remove %s: %s\n",
 			pathname, strerror (errno));
-	exit (1);
+	exit (CAIRO_TEST_FAILURE);
     }
 }
 
@@ -122,7 +122,8 @@ buffer_diff_core (unsigned char *_buf_a,
 }
 
 void
-compare_surfaces (cairo_surface_t	*surface_a,
+compare_surfaces (const cairo_test_context_t  *ctx,
+	          cairo_surface_t	*surface_a,
 		  cairo_surface_t	*surface_b,
 		  cairo_surface_t	*surface_diff,
 		  buffer_diff_result_t	*result)
@@ -150,14 +151,15 @@ compare_surfaces (cairo_surface_t	*surface_a,
     if (result->pixels_changed == 0)
 	return;
 
-    cairo_test_log ("%d pixels differ (with maximum difference of %d) from reference image\n",
+    cairo_test_log (ctx,
+	            "%d pixels differ (with maximum difference of %d) from reference image\n",
 		    result->pixels_changed, result->max_diff);
 
     /* Then, if there are any different pixels, we give the pdiff code
      * a crack at the images. If it decides that there are no visually
      * discernible differences in any pixels, then we accept this
      * result as good enough.
-     * 
+     *
      * Only let pdiff have a crack at the comparison if the max difference
      * is lower than a threshold, otherwise some problems could be masked.
      */
@@ -166,7 +168,8 @@ compare_surfaces (cairo_surface_t	*surface_a,
                                                     gamma, luminance, field_of_view);
         if (discernible_pixels_changed == 0) {
             result->pixels_changed = 0;
-            cairo_test_log ("But perceptual diff finds no visually discernible difference.\n"
+            cairo_test_log (ctx,
+		            "But perceptual diff finds no visually discernible difference.\n"
                             "Accepting result.\n");
         }
     }
@@ -208,7 +211,9 @@ stdio_write_func (void *closure, const unsigned char *data, unsigned int length)
  * extending from (x,y) to (width,height).
  */
 static void
-flatten_surface (cairo_surface_t **surface, int x, int y)
+flatten_surface (const cairo_test_context_t *ctx,
+	         cairo_surface_t **surface,
+		 int x, int y)
 {
     cairo_surface_t *flat;
     cairo_t *cr;
@@ -219,14 +224,17 @@ flatten_surface (cairo_surface_t **surface, int x, int y)
     cairo_surface_set_device_offset (flat, -x, -y);
 
     cr = cairo_create (flat);
+    cairo_surface_destroy (flat);
+
     cairo_set_source_rgb (cr, 1, 1, 1);
     cairo_paint (cr);
+
     cairo_set_source_surface (cr, *surface, 0, 0);
+    cairo_surface_destroy (*surface);
     cairo_paint (cr);
-    cairo_destroy (cr);
 
-    cairo_surface_destroy (*surface);
-    *surface = flat;
+    *surface = cairo_surface_reference (cairo_get_target (cr));
+    cairo_destroy (cr);
 }
 
 /* Given an image surface, create a new surface that has the same
@@ -235,7 +243,9 @@ flatten_surface (cairo_surface_t **surface, int x, int y)
  * The original surface will be destroyed.
  */
 static void
-extract_sub_surface (cairo_surface_t **surface, int x, int y)
+extract_sub_surface (const cairo_test_context_t *ctx,
+	             cairo_surface_t **surface,
+		     int x, int y)
 {
     cairo_surface_t *sub;
     cairo_t *cr;
@@ -250,13 +260,15 @@ extract_sub_surface (cairo_surface_t **surface, int x, int y)
      * time, so I'm leaving both here so I can look at both to see
      * which I like better. */
     cr = cairo_create (sub);
+    cairo_surface_destroy (sub);
+
     cairo_set_source_surface (cr, *surface, -x, -y);
+    cairo_surface_destroy (*surface);
     cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
     cairo_paint (cr);
-    cairo_destroy (cr);
 
-    cairo_surface_destroy (*surface);
-    *surface = sub;
+    *surface = cairo_surface_reference (cairo_get_target (cr));
+    cairo_destroy (cr);
 }
 
 /* Image comparison code courtesy of Richard Worth <richard@theworths.org>
@@ -275,7 +287,8 @@ extract_sub_surface (cairo_surface_t **surface, int x, int y)
  * oh well).
  */
 static cairo_status_t
-image_diff_core (const char *filename_a,
+image_diff_core (const cairo_test_context_t *ctx,
+	         const char *filename_a,
 		 const char *filename_b,
 		 const char *filename_diff,
 		 int		ax,
@@ -293,7 +306,7 @@ image_diff_core (const char *filename_a,
     surface_a = cairo_image_surface_create_from_png (filename_a);
     status = cairo_surface_status (surface_a);
     if (status) {
-	cairo_test_log ("Error: Failed to create surface from %s: %s\n",
+	cairo_test_log (ctx, "Error: Failed to create surface from %s: %s\n",
 			filename_a, cairo_status_to_string (status));
 	return status;
     }
@@ -301,28 +314,45 @@ image_diff_core (const char *filename_a,
     surface_b = cairo_image_surface_create_from_png (filename_b);
     status = cairo_surface_status (surface_b);
     if (status) {
-	cairo_test_log ("Error: Failed to create surface from %s: %s\n",
+	cairo_test_log (ctx, "Error: Failed to create surface from %s: %s\n",
 			filename_b, cairo_status_to_string (status));
 	cairo_surface_destroy (surface_a);
 	return status;
     }
 
     if (flatten) {
-	flatten_surface (&surface_a, ax, ay);
-	flatten_surface (&surface_b, bx, by);
+	flatten_surface (ctx, &surface_a, ax, ay);
+	flatten_surface (ctx, &surface_b, bx, by);
 	ax = ay = bx = by = 0;
     }
 
     if (ax || ay) {
-	extract_sub_surface (&surface_a, ax, ay);
+	extract_sub_surface (ctx, &surface_a, ax, ay);
 	ax = ay = 0;
     }
 
     if (bx || by) {
-	extract_sub_surface (&surface_b, bx, by);
+	extract_sub_surface (ctx, &surface_b, bx, by);
 	bx = by = 0;
     }
 
+    status = cairo_surface_status (surface_a);
+    if (status) {
+	cairo_test_log (ctx, "Error: Failed to extract surface from %s: %s\n",
+			filename_a, cairo_status_to_string (status));
+	cairo_surface_destroy (surface_a);
+	cairo_surface_destroy (surface_b);
+	return status;
+    }
+    status = cairo_surface_status (surface_b);
+    if (status) {
+	cairo_test_log (ctx, "Error: Failed to extract surface from %s: %s\n",
+			filename_b, cairo_status_to_string (status));
+	cairo_surface_destroy (surface_a);
+	cairo_surface_destroy (surface_b);
+	return status;
+    }
+
     width_a = cairo_image_surface_get_width (surface_a);
     height_a = cairo_image_surface_get_height (surface_a);
     stride_a = cairo_image_surface_get_stride (surface_a);
@@ -334,7 +364,7 @@ image_diff_core (const char *filename_a,
 	height_a != height_b ||
 	stride_a != stride_b)
     {
-	cairo_test_log ("Error: Image size mismatch: (%dx%d) vs. (%dx%d)\n"
+	cairo_test_log (ctx, "Error: Image size mismatch: (%dx%d) vs. (%dx%d)\n"
 			"       for %s vs. %s\n",
 			width_a, height_a,
 			width_b, height_b,
@@ -346,25 +376,49 @@ image_diff_core (const char *filename_a,
 
     surface_diff = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
 					       width_a, height_a);
+    status = cairo_surface_status (surface_diff);
+    if (status) {
+	cairo_test_log (ctx, "Error: Failed to allocate surface to hold differences\n");
+	cairo_surface_destroy (surface_a);
+	cairo_surface_destroy (surface_b);
+	return CAIRO_STATUS_NO_MEMORY;
+    }
 
-    compare_surfaces (surface_a, surface_b, surface_diff, result);
+
+    compare_surfaces (ctx, surface_a, surface_b, surface_diff, result);
 
     status = CAIRO_STATUS_SUCCESS;
     if (result->pixels_changed) {
 	FILE *png_file;
 
-	if (filename_diff)
+	if (filename_diff) {
 	    png_file = fopen (filename_diff, "wb");
-	else
+	    if (png_file == NULL) {
+		int err = errno;
+
+		cairo_surface_destroy (surface_a);
+		cairo_surface_destroy (surface_b);
+		cairo_surface_destroy (surface_diff);
+
+		switch (err) {
+		    case ENOMEM:
+			return CAIRO_STATUS_NO_MEMORY;
+		    default:
+			return CAIRO_STATUS_WRITE_ERROR;
+		}
+	    }
+	} else
 	    png_file = stdout;
 
-	status = cairo_surface_write_to_png_stream (surface_diff, stdio_write_func, png_file);
+	status = cairo_surface_write_to_png_stream (surface_diff,
+						    stdio_write_func,
+						    png_file);
 
 	if (png_file != stdout)
 	    fclose (png_file);
     } else {
 	if (filename_diff)
-	    xunlink (filename_diff);
+	    xunlink (ctx, filename_diff);
     }
 
     cairo_surface_destroy (surface_a);
@@ -375,7 +429,8 @@ image_diff_core (const char *filename_a,
 }
 
 cairo_status_t
-image_diff (const char *filename_a,
+image_diff (const cairo_test_context_t *ctx,
+	    const char *filename_a,
 	    const char *filename_b,
 	    const char *filename_diff,
 	    int		ax,
@@ -384,13 +439,15 @@ image_diff (const char *filename_a,
 	    int		by,
 	    buffer_diff_result_t *result)
 {
-    return image_diff_core (filename_a, filename_b, filename_diff,
+    return image_diff_core (ctx,
+	                    filename_a, filename_b, filename_diff,
 			    ax, ay, bx, by,
 			    result, FALSE);
 }
 
 cairo_status_t
-image_diff_flattened (const char *filename_a,
+image_diff_flattened (const cairo_test_context_t *ctx,
+	              const char *filename_a,
 		      const char *filename_b,
 		      const char *filename_diff,
 		      int	  ax,
@@ -399,7 +456,8 @@ image_diff_flattened (const char *filename_a,
 		      int	  by,
 		      buffer_diff_result_t *result)
 {
-    return image_diff_core (filename_a, filename_b, filename_diff,
+    return image_diff_core (ctx,
+	                    filename_a, filename_b, filename_diff,
 			    ax, ay, bx, by,
 			    result, TRUE);
 }