From e1bcd7529e534f4f33b1564243fb5fe56a2ba13c Mon Sep 17 00:00:00 2001
From: Ting-Wei Lan <lantw@src.gnome.org>
Date: Wed, 24 Oct 2018 21:46:16 +0800
Subject: [PATCH] build: Use weak bindings in gvdb to fix linking with LLD

Since tests/dconf-mock-gvdb.c has functions conflicting with the real
gvdb and it is intended for the former to override the latter in tests,
we have to make functions in gvdb library have weak bindings instead of
the default strong bindings to avoid duplicate symbol errors.

Fixes https://gitlab.gnome.org/GNOME/dconf/issues/47
---
 gvdb-reader.h | 35 +++++++++++++++++++++++++----------
 1 file changed, 25 insertions(+), 10 deletions(-)

diff --git a/gvdb-reader.h b/gvdb-reader.h
index 9bf627f4b..79a97d358 100644
--- a/gvdb-reader.h
+++ b/gvdb-reader.h
@@ -22,40 +22,55 @@
 
 #include <glib.h>
 
+/* We cannot enable the weak attribute unconditionally here because both
+ * gvdb/gvdb-reader.c and tests/dconf-mock-gvdb.c include this file. The
+ * intention of using weak symbols here is to allow the latter to override
+ * functions defined in the former, so functions in tests/dconf-mock-gvdb.c
+ * must have strong bindings. */
+#ifdef GVDB_USE_WEAK_SYMBOLS
+# ifdef __GNUC__
+#  define GVDB_GNUC_WEAK __attribute__((weak))
+# else
+#  define GVDB_GNUC_WEAK
+# endif
+#else
+# define GVDB_GNUC_WEAK
+#endif
+
 typedef struct _GvdbTable GvdbTable;
 
 G_BEGIN_DECLS
 
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 GvdbTable *             gvdb_table_new_from_bytes                       (GBytes       *bytes,
                                                                          gboolean      trusted,
                                                                          GError      **error);
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 GvdbTable *             gvdb_table_new                                  (const gchar  *filename,
                                                                          gboolean      trusted,
                                                                          GError      **error);
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 void                    gvdb_table_free                                 (GvdbTable    *table);
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 gchar **                gvdb_table_get_names                            (GvdbTable    *table,
                                                                          gsize        *length);
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 gchar **                gvdb_table_list                                 (GvdbTable    *table,
                                                                          const gchar  *key);
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 GvdbTable *             gvdb_table_get_table                            (GvdbTable    *table,
                                                                          const gchar  *key);
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 GVariant *              gvdb_table_get_raw_value                        (GvdbTable    *table,
                                                                          const gchar  *key);
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 GVariant *              gvdb_table_get_value                            (GvdbTable    *table,
                                                                          const gchar  *key);
 
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 gboolean                gvdb_table_has_value                            (GvdbTable    *table,
                                                                          const gchar  *key);
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 gboolean                gvdb_table_is_valid                             (GvdbTable    *table);
 
 G_END_DECLS