[gnome-online-accounts] backend: Use constructor to setup gettext

[Debarshi Ray <debarshir src gnome org>]

commit bbab1cebf4d976b51680a2ab6c4730b9580f5098
Author: Ting-Wei Lan <lantw src gnome org>
Date:   Sun May 22 00:51:26 2016 +0800

    backend: Use constructor to setup gettext
    
    To ensure the translation data are loaded from the correct prefix even
    if libintl and gnome-online-accounts are installed in different
    prefixes, we must call bindtextdomain and bind_textdomain_codeset
    before translating messages.
    
    To keep the code clean, gconstructor.h from GLib is copied to support
    running code when the library is loaded, so we can have a constructor
    to call gettext functions.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=760440

 src/goabackend/Makefile.am      |    1 +
 src/goabackend/gconstructor.h   |  120 +++++++++++++++++++++++++++++++++++++++
 src/goabackend/goabackendinit.c |   41 +++++++++++++
 3 files changed, 162 insertions(+), 0 deletions(-)
---
diff --git a/src/goabackend/Makefile.am b/src/goabackend/Makefile.am
index 909c55c..40b76dc 100644
--- a/src/goabackend/Makefile.am
+++ b/src/goabackend/Makefile.am
@@ -68,6 +68,7 @@ libgoa_backend_1_0_la_SOURCES =                                               \
        goabackend.h                                                    \
        goabackendenums-priv.h                                          \
        goabackendenumtypes.h           goabackendenumtypes.c           \
+       gconstructor.h                  goabackendinit.c                \
        goadlnaservermanager.h          goadlnaservermanager.c          \
        goaewsclient.h                  goaewsclient.c                  \
        goahttpclient.h                 goahttpclient.c                 \
diff --git a/src/goabackend/gconstructor.h b/src/goabackend/gconstructor.h
new file mode 100644
index 0000000..dccb031
--- /dev/null
+++ b/src/goabackend/gconstructor.h
@@ -0,0 +1,120 @@
+/*
+  If G_HAS_CONSTRUCTORS is true then the compiler support *both* constructors and
+  destructors, in a sane way, including e.g. on library unload. If not you're on
+  your own.
+
+  Some compilers need #pragma to handle this, which does not work with macros,
+  so the way you need to use this is (for constructors):
+
+  #ifdef G_DEFINE_CONSTRUCTOR_NEEDS_PRAGMA
+  #pragma G_DEFINE_CONSTRUCTOR_PRAGMA_ARGS(my_constructor)
+  #endif
+  G_DEFINE_CONSTRUCTOR(my_constructor)
+  static void my_constructor(void) {
+   ...
+  }
+
+*/
+
+#ifndef __GTK_DOC_IGNORE__
+
+#if  __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 7)
+
+#define G_HAS_CONSTRUCTORS 1
+
+#define G_DEFINE_CONSTRUCTOR(_func) static void __attribute__((constructor)) _func (void);
+#define G_DEFINE_DESTRUCTOR(_func) static void __attribute__((destructor)) _func (void);
+
+#elif defined (_MSC_VER) && (_MSC_VER >= 1500)
+/* Visual studio 2008 and later has _Pragma */
+
+#define G_HAS_CONSTRUCTORS 1
+
+/* We do some weird things to avoid the constructors being optimized
+ * away on VS2015 if WholeProgramOptimization is enabled. First we
+ * make a reference to the array from the wrapper to make sure its
+ * references. Then we use a pragma to make sure the wrapper function
+ * symbol is always included at the link stage. Also, the symbols
+ * need to be extern (but not dllexport), even though they are not
+ * really used from another object file.
+ */
+
+/* We need to account for differences between the mangling of symbols
+ * for Win32 (x86) and x64 programs, as symbols on Win32 are prefixed
+ * with an underscore but symbols on x64 are not.
+ */
+#ifdef _WIN64
+#define G_MSVC_SYMBOL_PREFIX ""
+#else
+#define G_MSVC_SYMBOL_PREFIX "_"
+#endif
+
+#define G_DEFINE_CONSTRUCTOR(_func) G_MSVC_CTOR (_func, G_MSVC_SYMBOL_PREFIX)
+#define G_DEFINE_DESTRUCTOR(_func) G_MSVC_DTOR (_func, G_MSVC_SYMBOL_PREFIX)
+
+#define G_MSVC_CTOR(_func,_sym_prefix) \
+  static void _func(void); \
+  extern int (* _array ## _func)(void);              \
+  int _func ## _wrapper(void) { _func(); g_slist_find (NULL,  _array ## _func); return 0; } \
+  __pragma(comment(linker,"/include:" _sym_prefix # _func "_wrapper")) \
+  __pragma(section(".CRT$XCU",read)) \
+  __declspec(allocate(".CRT$XCU")) int (* _array ## _func)(void) = _func ## _wrapper;
+
+#define G_MSVC_DTOR(_func,_sym_prefix) \
+  static void _func(void); \
+  extern int (* _array ## _func)(void);              \
+  int _func ## _constructor(void) { atexit (_func); g_slist_find (NULL,  _array ## _func); return 0; } \
+   __pragma(comment(linker,"/include:" _sym_prefix # _func "_constructor")) \
+  __pragma(section(".CRT$XCU",read)) \
+  __declspec(allocate(".CRT$XCU")) int (* _array ## _func)(void) = _func ## _constructor;
+
+#elif defined (_MSC_VER)
+
+#define G_HAS_CONSTRUCTORS 1
+
+/* Pre Visual studio 2008 must use #pragma section */
+#define G_DEFINE_CONSTRUCTOR_NEEDS_PRAGMA 1
+#define G_DEFINE_DESTRUCTOR_NEEDS_PRAGMA 1
+
+#define G_DEFINE_CONSTRUCTOR_PRAGMA_ARGS(_func) \
+  section(".CRT$XCU",read)
+#define G_DEFINE_CONSTRUCTOR(_func) \
+  static void _func(void); \
+  static int _func ## _wrapper(void) { _func(); return 0; } \
+  __declspec(allocate(".CRT$XCU")) static int (*p)(void) = _func ## _wrapper;
+
+#define G_DEFINE_DESTRUCTOR_PRAGMA_ARGS(_func) \
+  section(".CRT$XCU",read)
+#define G_DEFINE_DESTRUCTOR(_func) \
+  static void _func(void); \
+  static int _func ## _constructor(void) { atexit (_func); return 0; } \
+  __declspec(allocate(".CRT$XCU")) static int (* _array ## _func)(void) = _func ## _constructor;
+
+#elif defined(__SUNPRO_C)
+
+/* This is not tested, but i believe it should work, based on:
+ * http://opensource.apple.com/source/OpenSSL098/OpenSSL098-35/src/fips/fips_premain.c
+ */
+
+#define G_HAS_CONSTRUCTORS 1
+
+#define G_DEFINE_CONSTRUCTOR_NEEDS_PRAGMA 1
+#define G_DEFINE_DESTRUCTOR_NEEDS_PRAGMA 1
+
+#define G_DEFINE_CONSTRUCTOR_PRAGMA_ARGS(_func) \
+  init(_func)
+#define G_DEFINE_CONSTRUCTOR(_func) \
+  static void _func(void);
+
+#define G_DEFINE_DESTRUCTOR_PRAGMA_ARGS(_func) \
+  fini(_func)
+#define G_DEFINE_DESTRUCTOR(_func) \
+  static void _func(void);
+
+#else
+
+/* constructors not supported for this compiler */
+
+#endif
+
+#endif /* __GTK_DOC_IGNORE__ */
diff --git a/src/goabackend/goabackendinit.c b/src/goabackend/goabackendinit.c
new file mode 100644
index 0000000..c40fd2e
--- /dev/null
+++ b/src/goabackend/goabackendinit.c
@@ -0,0 +1,41 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+/*
+ * Copyright © 2016 Ting-Wei Lan <lantw src gnome org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General
+ * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <glib/gi18n-lib.h>
+
+#include "gconstructor.h"
+
+#if defined (G_HAS_CONSTRUCTORS)
+
+#ifdef G_DEFINE_CONSTRUCTOR_NEEDS_PRAGMA
+#pragma G_DEFINE_CONSTRUCTOR_PRAGMA_ARGS(goa_backend_init_ctor)
+#endif
+G_DEFINE_CONSTRUCTOR(goa_backend_init_ctor)
+
+static void
+goa_backend_init_ctor (void)
+{
+  bindtextdomain (GETTEXT_PACKAGE, PACKAGE_LOCALE_DIR);
+  bind_textdomain_codeset (GETTEXT_PACKAGE, "UTF-8");
+}
+
+#else
+# error Your platform/compiler is missing constructor support
+#endif