[cp-patches] RFC: Some cairo error reporting help

[Mark Wielaard]

Hi,

We currently just crash and burn when we have trouble with cairo. This
doesn't really help the user. The following make sure we output a stack
trace and reset the cairo status after a failed drawing operation. Which
will hopefully help the user determine how to work around things.

2006-02-18  Mark Wielaard  <[EMAIL PROTECTED]>

    * native/jni/gtk-peer/gnu_java_awt_peer_gtk_GdkGraphics2D.c
    (begin_drawing_operation): Output stacktrace and return on bad cairo
    status.
    (end_drawing_operation): Likewise. And reset cairo_t.

Does this seem useful?

Sample output:

java.lang.InternalError: out of memory
   at gnu.java.awt.peer.gtk.GdkGraphics2D.cairoFill (Native Method)
   at gnu.java.awt.peer.gtk.GdkGraphics2D.fillRect (GdkGraphics2D.java:1076)
   at com.jgoodies.plaf.plastic.PlasticUtils.add3DEffekt (PlasticUtils.java:257)
   at com.jgoodies.plaf.plastic.PlasticUtils.addLight3DEffekt 
(PlasticUtils.java:285)
   at com.jgoodies.plaf.plastic.PlasticToolBarUI.update 
(PlasticToolBarUI.java:164)
   [...]

I don't know the status of the Graphics2D rewrite that Tom was working
on. Maybe that makes this hack unnecessary. If it interferes with that
please yell and scream. I haven't actually found and fixed any real
problems with this patch yet.

Cheers,

Mark


Index: native/jni/gtk-peer/gnu_java_awt_peer_gtk_GdkGraphics2D.c
===================================================================
RCS file: /cvsroot/classpath/classpath/native/jni/gtk-peer/gnu_java_awt_peer_gtk_GdkGraphics2D.c,v
retrieving revision 1.36
diff -u -r1.36 gnu_java_awt_peer_gtk_GdkGraphics2D.c
--- native/jni/gtk-peer/gnu_java_awt_peer_gtk_GdkGraphics2D.c	16 Nov 2005 20:59:12 -0000	1.36
+++ native/jni/gtk-peer/gnu_java_awt_peer_gtk_GdkGraphics2D.c	18 Feb 2006 16:17:56 -0000
@@ -1,5 +1,5 @@
 /* gnu_java_awt_peer_gtk_GdkGraphics2d.c
-   Copyright (C) 2003, 2005  Free Software Foundation, Inc.
+   Copyright (C) 2003, 2005, 2006  Free Software Foundation, Inc.
 
    This file is part of GNU Classpath.
    
@@ -35,6 +35,7 @@
    obligated to do so.  If you do not wish to do so, delete this
    exception statement from your version. */
 
+#include "jcl.h"
 #include "gtkcairopeer.h"
 #include "gdkfont.h"
 #include "gnu_java_awt_peer_gtk_GdkGraphics2D.h"
@@ -261,7 +262,14 @@
 static void
 begin_drawing_operation (JNIEnv *env, struct graphics2d * gr)
 {  
-  g_assert(cairo_status (gr->cr) == CAIRO_STATUS_SUCCESS);
+  cairo_status_t cst = cairo_status (gr->cr);
+  if (cst != CAIRO_STATUS_SUCCESS)
+    {
+      const char *detail = cairo_status_to_string (cst);
+      JCL_ThrowException (env, "java/lang/InternalError", detail);
+      (*env)->ExceptionDescribe (env);
+      return;
+    }
 
   switch (gr->mode)
     {
@@ -312,7 +320,19 @@
 static void
 end_drawing_operation (JNIEnv *env, struct graphics2d * gr)
 {
-  g_assert(cairo_status (gr->cr) == CAIRO_STATUS_SUCCESS);
+  cairo_status_t cst = cairo_status (gr->cr);
+  if (cst != CAIRO_STATUS_SUCCESS)
+    {
+      /* Report error. */
+      const char *detail = cairo_status_to_string (cst);
+      JCL_ThrowException (env, "java/lang/InternalError", detail);
+      (*env)->ExceptionDescribe (env);
+
+      /* Recreate cairo status. */
+      cairo_destroy (gr->cr);
+      gr->cr = cairo_create (gr->surface);
+      return;
+    }
 
   switch (gr->mode)
     {

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