From 0fbae3d42c372f1fcc79dce52bd2b76dd44c646f Mon Sep 17 00:00:00 2001
From: Carl Worth <cworth@cworth.org>
Date: Mon, 26 Feb 2007 02:35:41 +0100
Subject: [PATCH] Add code to debug mutex deadlocks

This is somewhat unportable as it relies on non-POSIX error-checking
mutexes. Go go gadget _GNU_SOURCE\!
---
 src/Makefile.am         |    2 +-
 src/cairo-scaled-font.c |   12 ++++++++++++
 src/cairoint.h          |   16 +++++++++++++---
 3 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/src/Makefile.am b/src/Makefile.am
index 4a24ac2..47b5823 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -243,7 +243,7 @@ libcairo_la_SOURCES =				\
 
 libcairo_la_LDFLAGS = -version-info @VERSION_INFO@ -no-undefined $(export_symbols)
 
-INCLUDES = -I$(srcdir) -I$(top_srcdir)/pixman/src $(CAIRO_CFLAGS)
+INCLUDES = -D_GNU_SOURCE -I$(srcdir) -I$(top_srcdir)/pixman/src $(CAIRO_CFLAGS)
 
 libcairo_la_LIBADD = $(top_builddir)/pixman/src/libpixman.la $(CAIRO_LIBS) $(noinst_LTLIBRARIES)
 
diff --git a/src/cairo-scaled-font.c b/src/cairo-scaled-font.c
index 02af487..6638c70 100755
--- a/src/cairo-scaled-font.c
+++ b/src/cairo-scaled-font.c
@@ -678,6 +678,10 @@ cairo_scaled_font_text_extents (cairo_scaled_font_t   *scaled_font,
     free (glyphs);
 }
 
+const char * CAIRO_MUTEX_LOCK_FILE;
+int CAIRO_MUTEX_LOCK_LINE;
+int CAIRO_MUTEX_LOCK_ERR;
+
 /**
  * cairo_scaled_font_glyph_extents:
  * @scaled_font: a #cairo_scaled_font_t
@@ -702,6 +706,7 @@ cairo_scaled_font_glyph_extents (cairo_scaled_font_t   *scaled_font,
 				 int                    num_glyphs,
 				 cairo_text_extents_t  *extents)
 {
+    int err;
     cairo_status_t status = CAIRO_STATUS_SUCCESS;
     int i;
     double min_x = 0.0, min_y = 0.0, max_x = 0.0, max_y = 0.0;
@@ -712,6 +717,13 @@ cairo_scaled_font_glyph_extents (cairo_scaled_font_t   *scaled_font,
 	return;
 
     CAIRO_MUTEX_LOCK (scaled_font->mutex);
+    if (CAIRO_MUTEX_LOCK_ERR == EDEADLK) {
+	fprintf (stderr,
+		 "Deadlock occurred in cairo_scaled_font_glyph_extents.\n"
+		 "The original locker was %s:%d\n",
+		 CAIRO_MUTEX_LOCK_FILE, CAIRO_MUTEX_LOCK_LINE);
+	exit (1);
+    }
 
     for (i = 0; i < num_glyphs; i++) {
 	double			left, top, right, bottom;
diff --git a/src/cairoint.h b/src/cairoint.h
index 2c145e0..7279239 100755
--- a/src/cairoint.h
+++ b/src/cairoint.h
@@ -46,6 +46,8 @@
 #ifndef _CAIROINT_H_
 #define _CAIROINT_H_
 
+#include <errno.h>
+
 #if HAVE_CONFIG_H
 #include "config.h"
 #endif
@@ -134,11 +136,19 @@ CAIRO_BEGIN_DECLS
 #define __attribute__(x)
 #endif
 
+extern const char * CAIRO_MUTEX_LOCK_FILE;
+extern int CAIRO_MUTEX_LOCK_LINE;
+extern int CAIRO_MUTEX_LOCK_ERR;
+
 #if HAVE_PTHREAD_H
 # include <pthread.h>
-# define CAIRO_MUTEX_DECLARE(name) static pthread_mutex_t name = PTHREAD_MUTEX_INITIALIZER
-# define CAIRO_MUTEX_DECLARE_GLOBAL(name) pthread_mutex_t name = PTHREAD_MUTEX_INITIALIZER
-# define CAIRO_MUTEX_LOCK(name) pthread_mutex_lock (&name)
+# define CAIRO_MUTEX_DECLARE(name) static pthread_mutex_t name = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP
+# define CAIRO_MUTEX_DECLARE_GLOBAL(name) pthread_mutex_t name = PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP
+# define CAIRO_MUTEX_LOCK(name) do {	 		\
+    CAIRO_MUTEX_LOCK_ERR  = pthread_mutex_lock (&name);	\
+    CAIRO_MUTEX_LOCK_FILE = __FILE__;			\
+    CAIRO_MUTEX_LOCK_LINE = __LINE__;			\
+} while (0)
 # define CAIRO_MUTEX_UNLOCK(name) pthread_mutex_unlock (&name)
 typedef pthread_mutex_t cairo_mutex_t;
 # define CAIRO_MUTEX_INIT(mutex) pthread_mutex_init ((mutex), NULL)
-- 
1.5.0.rc1.gf4b6c