Merge branch 'typeof' into 'master'

Use C++11 decltype where possible

See merge request GNOME/glib!1575

9 files changed, 145 insertions, 50 deletions

diff --git a/docs/reference/glib/glib-sections.txt b/docs/reference/glib/glib-sections.txt
index e96e6c86b..02bb2ba50 100644
--- a/docs/reference/glib/glib-sections.txt
+++ b/docs/reference/glib/glib-sections.txt
@@ -730,7 +730,7 @@ GLIB_UNAVAILABLE_TYPE
 G_ANALYZER_ANALYZING
 G_ANALYZER_NORETURN
 g_autoptr_cleanup_generic_gfree
-g_has_typeof
+glib_typeof
 g_macro__has_attribute
 g_macro__has_builtin
 g_macro__has_feature
diff --git a/gio/gcredentials.c b/gio/gcredentials.c
index 146829e7c..9423f9ef9 100644
--- a/gio/gcredentials.c
+++ b/gio/gcredentials.c
@@ -225,7 +225,7 @@ g_credentials_to_string (GCredentials *credentials)
 {
   GString *ret;
 #if G_CREDENTIALS_USE_APPLE_XUCRED
-  __typeof__(credentials->native.cr_ngroups) i;
+  glib_typeof (credentials->native.cr_ngroups) i;
 #endif
 
   g_return_val_if_fail (G_IS_CREDENTIALS (credentials), NULL);
diff --git a/glib/gatomic.h b/glib/gatomic.h
index 6bf41bb74..bb1435c70 100644
--- a/glib/gatomic.h
+++ b/glib/gatomic.h
@@ -103,24 +103,24 @@ G_END_DECLS
     __atomic_store ((gint *)(atomic), &gais_temp, __ATOMIC_SEQ_CST);         \
   }))
 
-#if defined(g_has_typeof)
-#define g_atomic_pointer_get(atomic) \
-  (G_GNUC_EXTENSION ({                                                       \
-    G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer));                 \
-    __typeof__(*(atomic)) gapg_temp_newval;                                  \
-    __typeof__((atomic)) gapg_temp_atomic = (atomic);                        \
-    __atomic_load (gapg_temp_atomic, &gapg_temp_newval, __ATOMIC_SEQ_CST);   \
-    gapg_temp_newval;                                                        \
-  }))
-#define g_atomic_pointer_set(atomic, newval) \
-  (G_GNUC_EXTENSION ({                                                       \
-    G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer));                 \
-    __typeof__((atomic)) gaps_temp_atomic = (atomic);                        \
-    __typeof__(*(atomic)) gaps_temp_newval = (newval);                       \
-    (void) (0 ? (gpointer) *(atomic) : NULL);                                \
-    __atomic_store (gaps_temp_atomic, &gaps_temp_newval, __ATOMIC_SEQ_CST);  \
-  }))
-#else  /* if !defined(g_has_typeof) */
+#if defined(glib_typeof)
+#define g_atomic_pointer_get(atomic)                                       \
+  (G_GNUC_EXTENSION ({                                                     \
+    G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer));               \
+    glib_typeof (*(atomic)) gapg_temp_newval;                              \
+    glib_typeof ((atomic)) gapg_temp_atomic = (atomic);                    \
+    __atomic_load (gapg_temp_atomic, &gapg_temp_newval, __ATOMIC_SEQ_CST); \
+    gapg_temp_newval;                                                      \
+  }))
+#define g_atomic_pointer_set(atomic, newval)                                \
+  (G_GNUC_EXTENSION ({                                                      \
+    G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer));                \
+    glib_typeof ((atomic)) gaps_temp_atomic = (atomic);                     \
+    glib_typeof (*(atomic)) gaps_temp_newval = (newval);                    \
+    (void) (0 ? (gpointer) * (atomic) : NULL);                              \
+    __atomic_store (gaps_temp_atomic, &gaps_temp_newval, __ATOMIC_SEQ_CST); \
+  }))
+#else /* if !defined(glib_typeof) */
 #define g_atomic_pointer_get(atomic) \
   (G_GNUC_EXTENSION ({                                                       \
     G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer));                 \
@@ -137,7 +137,7 @@ G_END_DECLS
     (void) (0 ? (gpointer) *(atomic) : NULL);                                \
     __atomic_store (gaps_temp_atomic, &gaps_temp_newval, __ATOMIC_SEQ_CST);  \
   }))
-#endif  /* !defined(g_has_typeof) */
+#endif /* !defined(glib_typeof) */
 
 #define g_atomic_int_inc(atomic) \
   (G_GNUC_EXTENSION ({                                                       \
@@ -183,14 +183,25 @@ G_END_DECLS
     (guint) __atomic_fetch_xor ((atomic), (val), __ATOMIC_SEQ_CST);          \
   }))
 
+#if defined(glib_typeof)
+#define g_atomic_pointer_compare_and_exchange(atomic, oldval, newval) \
+  (G_GNUC_EXTENSION ({                                                       \
+    G_STATIC_ASSERT (sizeof (oldval) == sizeof (gpointer));                  \
+    glib_typeof ((oldval)) gapcae_oldval = (oldval);                         \
+    G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer));                 \
+    (void) (0 ? (gpointer) *(atomic) : NULL);                                \
+    __atomic_compare_exchange_n ((atomic), &gapcae_oldval, (newval), FALSE, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) ? TRUE : FALSE; \
+  }))
+#else /* if !defined(glib_typeof) */
 #define g_atomic_pointer_compare_and_exchange(atomic, oldval, newval) \
   (G_GNUC_EXTENSION ({                                                       \
     G_STATIC_ASSERT (sizeof (oldval) == sizeof (gpointer));                  \
-    __typeof__ ((oldval)) gapcae_oldval = (oldval);                          \
+    gpointer gapcae_oldval = (gpointer)(oldval);                             \
     G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer));                 \
     (void) (0 ? (gpointer) *(atomic) : NULL);                                \
     __atomic_compare_exchange_n ((atomic), &gapcae_oldval, (newval), FALSE, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) ? TRUE : FALSE; \
   }))
+#endif /* defined(glib_typeof) */
 #define g_atomic_pointer_add(atomic, val) \
   (G_GNUC_EXTENSION ({                                                       \
     G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer));                 \
@@ -283,14 +294,25 @@ G_END_DECLS
     __asm__ __volatile__ ("" : : : "memory");                                \
     gapg_result;                                                             \
   }))
+#if defined(glib_typeof)
+#define g_atomic_pointer_set(atomic, newval) \
+  (G_GNUC_EXTENSION ({                                                       \
+    G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer));                 \
+    (void) (0 ? (gpointer) *(atomic) : NULL);                                \
+    __sync_synchronize ();                                                   \
+    __asm__ __volatile__ ("" : : : "memory");                                \
+    *(atomic) = (glib_typeof (*(atomic))) (gsize) (newval);                  \
+  }))
+#else /* if !defined(glib_typeof) */
 #define g_atomic_pointer_set(atomic, newval) \
   (G_GNUC_EXTENSION ({                                                       \
     G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer));                 \
     (void) (0 ? (gpointer) *(atomic) : NULL);                                \
     __sync_synchronize ();                                                   \
     __asm__ __volatile__ ("" : : : "memory");                                \
-    *(atomic) = (__typeof__ (*(atomic))) (gsize) (newval);                   \
+    *(atomic) = (gpointer) (gsize) (newval);                                         \
   }))
+#endif /* defined(glib_typeof) */
 
 #define g_atomic_int_inc(atomic) \
   (G_GNUC_EXTENSION ({                                                       \
@@ -408,6 +430,6 @@ G_END_DECLS
 #define g_atomic_pointer_xor(atomic, val) \
   (g_atomic_pointer_xor ((atomic), (gsize) (val)))
 
-#endif /* defined(__GNUC__) && defined(G_ATOMIC_OP_USE_GCC_BUILTINS) */
+#endif /* defined(G_ATOMIC_LOCK_FREE) && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4) */
 
 #endif /* __G_ATOMIC_H__ */
diff --git a/glib/gmacros.h b/glib/gmacros.h
index d953de4c8..0dd9a41c2 100644
--- a/glib/gmacros.h
+++ b/glib/gmacros.h
@@ -231,9 +231,13 @@
  *
  * This symbol is private.
  */
-#undef g_has_typeof
+#undef glib_typeof
 #if defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)) && !defined(__cplusplus)
-#define g_has_typeof
+#define glib_typeof(t) __typeof__ (t)
+#elif defined(__cplusplus) && __cplusplus >= 201103L
+/* C++11 decltype() is close enough for our usage */
+#include <type_traits>
+#define glib_typeof(t) std::remove_reference<decltype (t)>::type
 #endif
 
 /*
diff --git a/glib/gmem.h b/glib/gmem.h
index 45671073b..924299b20 100644
--- a/glib/gmem.h
+++ b/glib/gmem.h
@@ -110,16 +110,18 @@ gpointer g_try_realloc_n  (gpointer	 mem,
 			   gsize	 n_blocks,
 			   gsize	 n_block_bytes) G_GNUC_WARN_UNUSED_RESULT;
 
-#if defined(g_has_typeof) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_58
-#define g_clear_pointer(pp, destroy)                                           \
-  G_STMT_START {                                                               \
-    G_STATIC_ASSERT (sizeof *(pp) == sizeof (gpointer));                       \
-    __typeof__((pp)) _pp = (pp);                                               \
-    __typeof__(*(pp)) _ptr = *_pp;                                             \
-    *_pp = NULL;                                                               \
-    if (_ptr)                                                                  \
-      (destroy) (_ptr);                                                        \
-  } G_STMT_END                                                                 \
+#if defined(glib_typeof) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_58
+#define g_clear_pointer(pp, destroy)                     \
+  G_STMT_START                                           \
+  {                                                      \
+    G_STATIC_ASSERT (sizeof *(pp) == sizeof (gpointer)); \
+    glib_typeof ((pp)) _pp = (pp);                       \
+    glib_typeof (*(pp)) _ptr = *_pp;                     \
+    *_pp = NULL;                                         \
+    if (_ptr)                                            \
+      (destroy) (_ptr);                                  \
+  }                                                      \
+  G_STMT_END                                             \
   GLIB_AVAILABLE_MACRO_IN_2_34
 #else /* __GNUC__ */
 #define g_clear_pointer(pp, destroy) \
@@ -211,8 +213,8 @@ g_steal_pointer (gpointer pp)
 }
 
 /* type safety */
-#if defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)) && !defined(__cplusplus) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_58
-#define g_steal_pointer(pp) ((__typeof__(*pp)) (g_steal_pointer) (pp))
+#if defined(glib_typeof) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_58
+#define g_steal_pointer(pp) ((glib_typeof (*pp)) (g_steal_pointer) (pp))
 #else  /* __GNUC__ */
 /* This version does not depend on gcc extensions, but gcc does not warn
  * about incompatible-pointer-types: */
diff --git a/glib/grcbox.h b/glib/grcbox.h
index c92791260..f78f5cb3b 100644
--- a/glib/grcbox.h
+++ b/glib/grcbox.h
@@ -71,18 +71,18 @@ gsize           g_atomic_rc_box_get_size        (gpointer        mem_block);
 #define g_atomic_rc_box_new0(type) \
   ((type *) g_atomic_rc_box_alloc0 (sizeof (type)))
 
-#ifdef g_has_typeof
+#ifdef glib_typeof
 /* Type check to avoid assigning references to different types */
-# define g_rc_box_acquire(mem_block) \
-  ((__typeof__(mem_block)) (g_rc_box_acquire) (mem_block))
-# define g_atomic_rc_box_acquire(mem_block) \
-  ((__typeof__(mem_block)) (g_atomic_rc_box_acquire) (mem_block))
+#define g_rc_box_acquire(mem_block) \
+  ((glib_typeof (mem_block)) (g_rc_box_acquire) (mem_block))
+#define g_atomic_rc_box_acquire(mem_block) \
+  ((glib_typeof (mem_block)) (g_atomic_rc_box_acquire) (mem_block))
 
 /* Type check to avoid duplicating data to different types */
-# define g_rc_box_dup(block_size,mem_block) \
-  ((__typeof__(mem_block)) (g_rc_box_dup) (block_size,mem_block))
-# define g_atomic_rc_box_dup(block_size,mem_block) \
-  ((__typeof__(mem_block)) (g_atomic_rc_box_dup) (block_size,mem_block))
+#define g_rc_box_dup(block_size, mem_block) \
+  ((glib_typeof (mem_block)) (g_rc_box_dup) (block_size, mem_block))
+#define g_atomic_rc_box_dup(block_size, mem_block) \
+  ((glib_typeof (mem_block)) (g_atomic_rc_box_dup) (block_size, mem_block))
 #endif
 
 G_END_DECLS
diff --git a/glib/tests/cxx.cpp b/glib/tests/cxx.cpp
new file mode 100644
index 000000000..c423b2fbc
--- /dev/null
+++ b/glib/tests/cxx.cpp
@@ -0,0 +1,64 @@
+/*
+ * Copyright 2020 Xavier Claessens
+ *
+ * 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 2.1 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 <glib.h>
+
+typedef struct
+{
+  int dummy;
+} MyObject;
+
+static void
+test_typeof (void)
+{
+#if __cplusplus >= 201103L
+  // Test that with C++11 we don't get those kind of errors:
+  // error: invalid conversion from ‘gpointer’ {aka ‘void*’} to ‘MyObject*’ [-fpermissive]
+  MyObject *obj = g_rc_box_new0 (MyObject);
+  MyObject *obj2 = g_rc_box_acquire (obj);
+  g_assert_true (obj2 == obj);
+
+  MyObject *obj3 = g_atomic_pointer_get (&obj2);
+  g_assert_true (obj3 == obj);
+
+  MyObject *obj4 = nullptr;
+  g_atomic_pointer_set (&obj4, obj3);
+  g_assert_true (obj4 == obj);
+
+  MyObject *obj5 = nullptr;
+  g_atomic_pointer_compare_and_exchange (&obj5, nullptr, obj4);
+  g_assert_true (obj5 == obj);
+
+  MyObject *obj6 = g_steal_pointer (&obj5);
+  g_assert_true (obj6 == obj);
+
+  g_clear_pointer (&obj6, g_rc_box_release);
+  g_rc_box_release (obj);
+#else
+  g_test_skip ("This test requires C++11 compiler");
+#endif
+}
+
+int
+main (int argc, char *argv[])
+{
+  g_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/C++/typeof", test_typeof);
+
+  return g_test_run ();
+}
diff --git a/glib/tests/meson.build b/glib/tests/meson.build
index 567f5eda4..1c78dbf08 100644
--- a/glib/tests/meson.build
+++ b/glib/tests/meson.build
@@ -14,6 +14,9 @@ glib_tests = {
   'collate' : {},
   'cond' : {},
   'convert' : {},
+  'cxx' : {
+    'source' : ['cxx.cpp'],
+  },
   'dataset' : {},
   'date' : {},
   'dir' : {},
diff --git a/gobject/gobject.h b/gobject/gobject.h
index 499329af2..bf5496c54 100644
--- a/gobject/gobject.h
+++ b/gobject/gobject.h
@@ -513,10 +513,10 @@ GLIB_AVAILABLE_IN_ALL
 void        g_object_remove_weak_pointer      (GObject        *object, 
                                                gpointer       *weak_pointer_location);
 
-#if defined(g_has_typeof) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_56
+#if defined(glib_typeof) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_56
 /* Make reference APIs type safe with macros */
-#define g_object_ref(Obj)      ((__typeof__(Obj)) (g_object_ref) (Obj))
-#define g_object_ref_sink(Obj) ((__typeof__(Obj)) (g_object_ref_sink) (Obj))
+#define g_object_ref(Obj) ((glib_typeof (Obj)) (g_object_ref) (Obj))
+#define g_object_ref_sink(Obj) ((glib_typeof (Obj)) (g_object_ref_sink) (Obj))
 #endif
 
 /**