[cairo] Multithreaded cairo-test

[Chris Wilson]

During MT cairo-test, we see short fread()s. However, this is not always
an error, so check the ferror() status before raising png_error().
--
Chris Wilson
-------------- next part --------------
diff --git a/src/cairo-png.c b/src/cairo-png.c
index 006cae3..aa3210f 100644
--- a/src/cairo-png.c
+++ b/src/cairo-png.c
@@ -206,8 +206,13 @@ stdio_write_func (png_structp png, png_bytep data, png_size_t size)
     FILE *fp;
 
     fp = png_get_io_ptr (png);
-    if (fwrite (data, 1, size, fp) != size)
-	png_error(png, "Write Error");
+    while (size) {
+	size_t ret = fwrite (data, 1, size, fp);
+	size -= ret;
+	data += ret;
+	if (size && ferror (fp))
+	    png_error(png, "Write Error");
+    }
 }
 
 /**
@@ -332,14 +337,14 @@ read_png (png_rw_ptr	read_func,
 	  void		*closure)
 {
     cairo_surface_t *surface = (cairo_surface_t*) &_cairo_surface_nil;
-    png_byte *data = NULL;
-    unsigned int i;
     png_struct *png = NULL;
     png_info *info;
+    volatile png_byte *data = NULL;
+    volatile png_byte **row_pointers = NULL;
     png_uint_32 png_width, png_height, stride;
     int depth, color_type, interlace;
+    unsigned int i;
     unsigned int pixel_size;
-    png_byte **row_pointers = NULL;
 
     /* XXX: Perhaps we'll want some other error handlers? */
     png = png_create_read_struct (PNG_LIBPNG_VER_STRING,
@@ -442,8 +447,13 @@ stdio_read_func (png_structp png, png_bytep data, png_size_t size)
     FILE *fp;
 
     fp = png_get_io_ptr (png);
-    if (fread (data, 1, size, fp) != size)
-	png_error(png, "Read Error");
+    while (size) {
+	size_t ret = fread (data, 1, size, fp);
+	size -= ret;
+	data += ret;
+	if (size && ferror (fp))
+	    png_error(png, "Read Error");
+    }
 }
 
 /**