[gegl] buffer: display GeglBuffer leak stacktraces if env vars are set

[Michael Henning <mhenning src gnome org>]

commit 498c0011c89b14998d67760a9be3546dd384a180
Author: Michael Henning <drawoc darkrefraction com>
Date:   Sat Apr 20 23:35:50 2013 -0400

    buffer: display GeglBuffer leak stacktraces if env vars are set
    
    If you want to see the allocation stack traces, you simply build
    with --enable-debug, and export GEGL_DEBUG=buffer-alloc

 gegl/buffer/gegl-buffer.c | 73 ++++++++++++++++++++++++++---------------------
 gegl/gegl-debug.h         |  9 ++++--
 gegl/gegl-init.c          |  9 +++++-
 3 files changed, 55 insertions(+), 36 deletions(-)
---
diff --git a/gegl/buffer/gegl-buffer.c b/gegl/buffer/gegl-buffer.c
index bfd0d4f..584d513 100644
--- a/gegl/buffer/gegl-buffer.c
+++ b/gegl/buffer/gegl-buffer.c
@@ -43,6 +43,7 @@
 #include "gegl-buffer-types.h"
 #include "gegl-buffer.h"
 #include "gegl-buffer-private.h"
+#include "gegl-debug.h"
 #include "gegl-tile-handler.h"
 #include "gegl-tile-storage.h"
 #include "gegl-tile-backend.h"
@@ -65,11 +66,10 @@
 #include "gegl-config.h"
 #include "gegl-buffer-cl-cache.h"
 
-/* #define GEGL_BUFFER_DEBUG_ALLOCATIONS */
+#ifdef GEGL_ENABLE_DEBUG
+#define DEBUG_ALLOCATIONS (gegl_debug_flags & GEGL_DEBUG_BUFFER_ALLOC)
+#endif
 
-/* #define GEGL_BUFFER_DEBUG_ALLOCATIONS to print allocation stack
- * traces for leaked GeglBuffers using GNU C libs backtrace_symbols()
- */
 #ifdef HAVE_EXECINFO_H
 #include <execinfo.h>
 #endif
@@ -335,7 +335,7 @@ gegl_buffer_set_property (GObject      *gobject,
     }
 }
 
-#ifdef GEGL_BUFFER_DEBUG_ALLOCATIONS
+#ifdef GEGL_ENABLE_DEBUG
 static GList *allocated_buffers_list = NULL;
 #endif
 static gint   allocated_buffers      = 0;
@@ -392,26 +392,27 @@ gegl_buffer_stats (void)
 gint
 gegl_buffer_leaks (void)
 {
-#ifdef GEGL_BUFFER_DEBUG_ALLOCATIONS
-  {
-    GList *leaked_buffer = NULL;
+#ifdef GEGL_ENABLE_DEBUG
+  if (DEBUG_ALLOCATIONS)
+    {
+      GList *leaked_buffer = NULL;
 
-    for (leaked_buffer = allocated_buffers_list;
-         leaked_buffer != NULL;
-         leaked_buffer = leaked_buffer->next)
-      {
-        GeglBuffer *buffer = GEGL_BUFFER (leaked_buffer->data);
+      for (leaked_buffer = allocated_buffers_list;
+           leaked_buffer != NULL;
+           leaked_buffer = leaked_buffer->next)
+        {
+          GeglBuffer *buffer = GEGL_BUFFER (leaked_buffer->data);
 
 #ifdef HAVE_EXECINFO_H
-        g_printerr ("\n"
-                   "Leaked buffer allocation stack trace:\n");
-        backtrace_symbols_fd (buffer->alloc_stack_trace, buffer->alloc_stack_size, fileno (stderr));
-        putc ('\n', stderr);
+          g_printerr ("\n"
+                     "Leaked buffer allocation stack trace:\n");
+          backtrace_symbols_fd (buffer->alloc_stack_trace, buffer->alloc_stack_size, fileno (stderr));
+          putc ('\n', stderr);
 #endif
-      }
-  }
-  g_list_free (allocated_buffers_list);
-  allocated_buffers_list = NULL;
+        }
+      g_list_free (allocated_buffers_list);
+      allocated_buffers_list = NULL;
+    }
 #endif
 
   return allocated_buffers - de_allocated_buffers;
@@ -471,9 +472,12 @@ gegl_buffer_dispose (GObject *object)
 static void
 gegl_buffer_finalize (GObject *object)
 {
-#ifdef GEGL_BUFFER_DEBUG_ALLOCATIONS
-  g_free (GEGL_BUFFER (object)->alloc_stack_trace);
-  allocated_buffers_list = g_list_remove (allocated_buffers_list, object);
+#ifdef GEGL_ENABLE_DEBUG
+  if (DEBUG_ALLOCATIONS)
+    {
+      g_free (GEGL_BUFFER (object)->alloc_stack_trace);
+      allocated_buffers_list = g_list_remove (allocated_buffers_list, object);
+    }
 #endif
 
   g_free (GEGL_BUFFER (object)->path);
@@ -945,15 +949,17 @@ gegl_buffer_class_init (GeglBufferClass *class)
 
 }
 
-#ifdef GEGL_BUFFER_DEBUG_ALLOCATIONS
+#ifdef GEGL_ENABLE_DEBUG
 #define MAX_N_FUNCTIONS 100
-
 static void
 gegl_buffer_set_alloc_stack (GeglBuffer *buffer)
 {
 #ifdef HAVE_EXECINFO_H
-  buffer->alloc_stack_trace = g_new (gpointer, MAX_N_FUNCTIONS);
-  buffer->alloc_stack_size = backtrace (buffer->alloc_stack_trace, MAX_N_FUNCTIONS);
+  if (DEBUG_ALLOCATIONS)
+    {
+      buffer->alloc_stack_trace = g_new (gpointer, MAX_N_FUNCTIONS);
+      buffer->alloc_stack_size = backtrace (buffer->alloc_stack_trace, MAX_N_FUNCTIONS);
+    }
 #endif
 }
 #endif
@@ -961,7 +967,7 @@ gegl_buffer_set_alloc_stack (GeglBuffer *buffer)
 void gegl_bt (void);
 void gegl_bt (void)
 {
-#ifdef GEGL_BUFFER_DEBUG_ALLOCATIONS
+#ifdef GEGL_ENABLE_DEBUG
 #ifndef HAVE_EXECINFO_H
   g_print ("backtrace() not available for this platform\n");
 #else
@@ -985,9 +991,12 @@ gegl_buffer_init (GeglBuffer *buffer)
 
   allocated_buffers++;
 
-#ifdef GEGL_BUFFER_DEBUG_ALLOCATIONS
-  gegl_buffer_set_alloc_stack (buffer);
-  allocated_buffers_list = g_list_prepend (allocated_buffers_list, buffer);
+#ifdef GEGL_ENABLE_DEBUG
+  if (DEBUG_ALLOCATIONS)
+    {
+      gegl_buffer_set_alloc_stack (buffer);
+      allocated_buffers_list = g_list_prepend (allocated_buffers_list, buffer);
+    }
 #endif
 }
 
diff --git a/gegl/gegl-debug.h b/gegl/gegl-debug.h
index 5fd1fd9..0a94090 100644
--- a/gegl/gegl-debug.h
+++ b/gegl/gegl-debug.h
@@ -15,7 +15,8 @@ typedef enum {
   GEGL_DEBUG_CACHE           = 1 << 5,
   GEGL_DEBUG_MISC            = 1 << 6,
   GEGL_DEBUG_INVALIDATION    = 1 << 7,
-  GEGL_DEBUG_OPENCL          = 1 << 8
+  GEGL_DEBUG_OPENCL          = 1 << 8,
+  GEGL_DEBUG_BUFFER_ALLOC    = 1 << 9
 } GeglDebugFlag;
 
 /* only compiled in from gegl-init.c but kept here to
@@ -32,15 +33,17 @@ static const GDebugKey gegl_debug_keys[] = {
   { "processor",     GEGL_DEBUG_PROCESSOR},
   { "invalidation",  GEGL_DEBUG_INVALIDATION},
   { "opencl",        GEGL_DEBUG_OPENCL},
+  { "buffer-alloc",  GEGL_DEBUG_BUFFER_ALLOC},
   { "all",           GEGL_DEBUG_PROCESS|
                      GEGL_DEBUG_BUFFER_LOAD|
                      GEGL_DEBUG_BUFFER_SAVE|
                      GEGL_DEBUG_TILE_BACKEND|
                      GEGL_DEBUG_PROCESSOR|
                      GEGL_DEBUG_CACHE|
-                     GEGL_DEBUG_OPENCL},
+                     GEGL_DEBUG_OPENCL|
+                     GEGL_DEBUG_BUFFER_ALLOC},
 };
-#endif /* GEGL_ENABLE_DEBUG */
+#endif /* __GEGL_INIT_C */
 
 #if defined(__cplusplus) && defined(GEGL_ISO_CXX_VARIADIC_MACROS)
 #  define GEGL_ISO_VARIADIC_MACROS 1
diff --git a/gegl/gegl-init.c b/gegl/gegl-init.c
index 4920643..56a9bf3 100644
--- a/gegl/gegl-init.c
+++ b/gegl/gegl-init.c
@@ -428,7 +428,14 @@ gegl_exit (void)
     }
 
   if (gegl_buffer_leaks ())
-    g_printf ("EEEEeEeek! %i GeglBuffers leaked\n", gegl_buffer_leaks ());
+    {
+      g_printf ("EEEEeEeek! %i GeglBuffers leaked\n", gegl_buffer_leaks ());
+#ifdef GEGL_ENABLE_DEBUG
+      if (!(gegl_debug_flags & GEGL_DEBUG_BUFFER_ALLOC))
+        g_printerr ("To debug GeglBuffer leaks, set the environment "
+                    "variable GEGL_DEBUG to \"buffer-alloc\"\n");
+#endif
+    }
   gegl_tile_cache_destroy ();
 
   if (gegl_swap_dir ())