[libdazzle] debug: add tracing helpers

[Christian Hergert <chergert src gnome org>]

commit 4602ab4bc7b3b1a148d6a206fcd2a314224d4252
Author: Christian Hergert <chergert redhat com>
Date:   Sat Jun 17 00:53:53 2017 -0700

    debug: add tracing helpers
    
    These can be used when -Denable_tracing=true is set. They compile out when
    that build option is not set. This header does not get installed, it is
    private to the library.

 src/dzl-debug.h.in |   83 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/meson.build    |    9 +++++
 2 files changed, 92 insertions(+), 0 deletions(-)
---
diff --git a/src/dzl-debug.h.in b/src/dzl-debug.h.in
new file mode 100644
index 0000000..c8286f3
--- /dev/null
+++ b/src/dzl-debug.h.in
@@ -0,0 +1,83 @@
+/* dzl-debug.h.in
+ *
+ * Copyright (C) 2013-2017 Christian Hergert <christian hergert me>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef DZL_DEBUG_H
+#define DZL_DEBUG_H
+
+#include <glib.h>
+
+G_BEGIN_DECLS
+
+#ifndef DZL_ENABLE_TRACE
+# define DZL_ENABLE_TRACE @ENABLE_TRACING@
+#endif
+#if DZL_ENABLE_TRACE != 1
+# undef DZL_ENABLE_TRACE
+#endif
+
+/**
+ * DZL_LOG_LEVEL_TRACE: (skip)
+ */
+#ifndef DZL_LOG_LEVEL_TRACE
+# define DZL_LOG_LEVEL_TRACE ((GLogLevelFlags)(1 << G_LOG_LEVEL_USER_SHIFT))
+#endif
+
+#ifdef DZL_ENABLE_TRACE
+# define DZL_TRACE_MSG(fmt, ...)                                         \
+   g_log(G_LOG_DOMAIN, DZL_LOG_LEVEL_TRACE, "  MSG: %s():%d: " fmt,       \
+         G_STRFUNC, __LINE__, ##__VA_ARGS__)
+# define DZL_PROBE                                                       \
+   g_log(G_LOG_DOMAIN, DZL_LOG_LEVEL_TRACE, "PROBE: %s():%d",            \
+         G_STRFUNC, __LINE__)
+# define DZL_TODO(_msg)                                                  \
+   g_log(G_LOG_DOMAIN, DZL_LOG_LEVEL_TRACE, " TODO: %s():%d: %s",        \
+         G_STRFUNC, __LINE__, _msg)
+# define DZL_ENTRY                                                       \
+   g_log(G_LOG_DOMAIN, DZL_LOG_LEVEL_TRACE, "ENTRY: %s():%d",            \
+         G_STRFUNC, __LINE__)
+# define DZL_EXIT                                                        \
+   G_STMT_START {                                                        \
+      g_log(G_LOG_DOMAIN, DZL_LOG_LEVEL_TRACE, " EXIT: %s():%d",         \
+            G_STRFUNC, __LINE__);                                        \
+      return;                                                            \
+   } G_STMT_END
+# define DZL_GOTO(_l)                                                    \
+   G_STMT_START {                                                        \
+      g_log(G_LOG_DOMAIN, DZL_LOG_LEVEL_TRACE, " GOTO: %s():%d ("#_l")", \
+            G_STRFUNC, __LINE__);                                        \
+      goto _l;                                                           \
+   } G_STMT_END
+# define DZL_RETURN(_r)                                                  \
+   G_STMT_START {                                                        \
+      g_log(G_LOG_DOMAIN, DZL_LOG_LEVEL_TRACE, " EXIT: %s():%d ",        \
+            G_STRFUNC, __LINE__);                                        \
+      return _r;                                                         \
+   } G_STMT_END
+#else
+# define DZL_TODO(_msg)
+# define DZL_PROBE
+# define DZL_TRACE_MSG(fmt, ...)
+# define DZL_ENTRY
+# define DZL_GOTO(_l)   goto _l
+# define DZL_EXIT       return
+# define DZL_RETURN(_r) return _r
+#endif
+
+G_END_DECLS
+
+#endif /* DZL_DEBUG_H */
diff --git a/src/meson.build b/src/meson.build
index 7dbcc0d..0017ae2 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -22,7 +22,16 @@ dzl_version_h = configure_file(
         install: true,
   configuration: version_data)
 
+debug_data = configuration_data()
+debug_data.set10('ENABLE_TRACING', get_option('enable_tracing'))
+
+dzl_debug_h = configure_file(
+          input: 'dzl-debug.h.in',
+         output: 'dzl-debug.h',
+  configuration: debug_data)
+
 libdazzle_generated_headers = [
+  dzl_debug_h,
   dzl_version_h,
 ]