src: Fix refcounting issues

Commit 5a455b1ead attempted to fix both GLib warnings around
floating references and other presumed refcounting issues. However
it missed 2 kinds of bugs:

- The places that take an IBusText created from a static string
  were made to avoid freeing it afterwards, but the staticness refers
  to the string content, not the object itself.
- The places that are documented to emit signals on floating object
  references used to do the following after signal emission:

  if (g_object_is_floating (object))
    g_object_unref (object)

  And did possibly trigger GLib warnings were changed to:

  if (g_object_is_floating (object))
    g_object_sink_ref (object);
  g_object_unref (object);

  Which fixes the GLib warning for floating references, but do
  unintendedly steal one reference away for non floating references.

This commit is essentially a revert of commit 5a455b1ead, but
addressing both things differently:

- All label/tooltip/symbol IBusText properties in IBusProperty do
  now always sink the reference of the stored object.

- All places documented as maybe using objects with a floating reference
  on signals changed to doing:

  if (g_object_is_floating (object)) {
    g_object_ref_sink (object);
    g_object_unref (object);
  }

  So the floating reference is owned and unreferenced without warnings,
  but already owned references are left unchanged.

This addresses the possible GLib warnings, fixes the possible double
unrefs happening on IBusText used in signals, and fixes the missing
unrefs on IBusText objects created from static strings.

BUG=https://github.com/ibus/ibus/issues/2393
BUG=https://github.com/ibus/ibus/issues/2387

src/ibusinputcontext.c

@@ -549,9 +549,10 @@ ibus_input_context_g_signal (GDBusProxy  *proxy,
         g_variant_unref (variant);
         g_signal_emit (context, context_signals[COMMIT_TEXT], 0, text);
 
-        if (g_object_is_floating (text))
+        if (g_object_is_floating (text)) {
             g_object_ref_sink (text);
-        g_object_unref (text);
+            g_object_unref (text);
+        }
         return;
     }
     if (g_strcmp0 (signal_name, "UpdatePreeditText") == 0) {
@@ -569,9 +570,10 @@ ibus_input_context_g_signal (GDBusProxy  *proxy,
                        cursor_pos,
                        visible);
 
-        if (g_object_is_floating (text))
+        if (g_object_is_floating (text)) {
             g_object_ref_sink (text);
-        g_object_unref (text);
+            g_object_unref (text);
+        }
         return;
     }
     if (g_strcmp0 (signal_name, "UpdatePreeditTextWithMode") == 0) {
@@ -592,9 +594,10 @@ ibus_input_context_g_signal (GDBusProxy  *proxy,
                        visible,
                        mode);
 
-        if (g_object_is_floating (text))
+        if (g_object_is_floating (text)) {
             g_object_ref_sink (text);
-        g_object_unref (text);
+            g_object_unref (text);
+        }
         return;
     }
 
@@ -621,9 +624,10 @@ ibus_input_context_g_signal (GDBusProxy  *proxy,
                        0,
                        text,
                        visible);
-        if (g_object_is_floating (text))
+        if (g_object_is_floating (text)) {
             g_object_ref_sink (text);
-        g_object_unref (text);
+            g_object_unref (text);
+        }
         return;
     }
 
@@ -640,9 +644,10 @@ ibus_input_context_g_signal (GDBusProxy  *proxy,
                        0,
                        table,
                        visible);
-        if (g_object_is_floating (table))
+        if (g_object_is_floating (table)) {
             g_object_ref_sink (table);
-        g_object_unref (table);
+            g_object_unref (table);
+        }
         return;
 
     }
@@ -659,9 +664,10 @@ ibus_input_context_g_signal (GDBusProxy  *proxy,
                        0,
                        prop_list);
 
-        if (g_object_is_floating (prop_list))
+        if (g_object_is_floating (prop_list)) {
             g_object_ref_sink (prop_list);
-        g_object_unref (prop_list);
+            g_object_unref (prop_list);
+        }
         return;
     }
 
@@ -673,9 +679,10 @@ ibus_input_context_g_signal (GDBusProxy  *proxy,
 
         g_signal_emit (context, context_signals[UPDATE_PROPERTY], 0, prop);
 
-        if (g_object_is_floating (prop))
+        if (g_object_is_floating (prop)) {
             g_object_ref_sink (prop);
-        g_object_unref (prop);
+            g_object_unref (prop);
+        }
         return;
     }
 

src/ibusproperty.c

@@ -336,20 +336,17 @@ ibus_property_destroy (IBusProperty *prop)
     prop->priv->icon = NULL;
 
     if (prop->priv->label) {
-        if (!ibus_text_get_is_static (prop->priv->label))
-            g_object_unref (prop->priv->label);
+        g_object_unref (prop->priv->label);
         prop->priv->label = NULL;
     }
 
     if (prop->priv->symbol) {
-        if (!ibus_text_get_is_static (prop->priv->symbol))
-            g_object_unref (prop->priv->symbol);
+        g_object_unref (prop->priv->symbol);
         prop->priv->symbol = NULL;
     }
 
     if (prop->priv->tooltip) {
-        if (!ibus_text_get_is_static (prop->priv->tooltip))
-            g_object_unref (prop->priv->tooltip);
+        g_object_unref (prop->priv->tooltip);
         prop->priv->tooltip = NULL;
     }
 
@@ -404,7 +401,7 @@ ibus_property_deserialize (IBusProperty *prop,
     g_variant_get_child (variant, retval++, "u", &prop->priv->type);
 
     GVariant *subvar = g_variant_get_child_value (variant, retval++);
-    if (prop->priv->label && !ibus_text_get_is_static (prop->priv->label)) {
+    if (prop->priv->label) {
         g_object_unref (prop->priv->label);
     }
     prop->priv->label = IBUS_TEXT (ibus_serializable_deserialize (subvar));
@@ -414,7 +411,7 @@ ibus_property_deserialize (IBusProperty *prop,
     ibus_g_variant_get_child_string (variant, retval++, &prop->priv->icon);
 
     subvar = g_variant_get_child_value (variant, retval++);
-    if (prop->priv->tooltip && !ibus_text_get_is_static (prop->priv->tooltip)) {
+    if (prop->priv->tooltip) {
         g_object_unref (prop->priv->tooltip);
     }
     prop->priv->tooltip = IBUS_TEXT (ibus_serializable_deserialize (subvar));
@@ -435,7 +432,7 @@ ibus_property_deserialize (IBusProperty *prop,
 
     /* Keep the serialized order for the compatibility when add new members. */
     subvar = g_variant_get_child_value (variant, retval++);
-    if (prop->priv->symbol && !ibus_text_get_is_static (prop->priv->symbol)) {
+    if (prop->priv->symbol) {
         g_object_unref (prop->priv->symbol);
     }
     prop->priv->symbol = IBUS_TEXT (ibus_serializable_deserialize (subvar));
@@ -567,7 +564,7 @@ ibus_property_set_label (IBusProperty *prop,
     g_assert (IBUS_IS_PROPERTY (prop));
     g_return_if_fail (label == NULL || IBUS_IS_TEXT (label));
 
-    if (prop->priv->label && !ibus_text_get_is_static (prop->priv->label)) {
+    if (prop->priv->label) {
         g_object_unref (prop->priv->label);
     }
 
@@ -575,8 +572,10 @@ ibus_property_set_label (IBusProperty *prop,
         prop->priv->label = ibus_text_new_from_static_string ("");
     }
     else {
-        prop->priv->label = g_object_ref_sink (label);
+        prop->priv->label = label;
     }
+
+    g_object_ref_sink (prop->priv->label);
 }
 
 void
@@ -586,7 +585,7 @@ ibus_property_set_symbol (IBusProperty *prop,
     g_assert (IBUS_IS_PROPERTY (prop));
     g_return_if_fail (symbol == NULL || IBUS_IS_TEXT (symbol));
 
-    if (prop->priv->symbol && !ibus_text_get_is_static (prop->priv->symbol)) {
+    if (prop->priv->symbol) {
         g_object_unref (prop->priv->symbol);
     }
 
@@ -594,8 +593,10 @@ ibus_property_set_symbol (IBusProperty *prop,
         prop->priv->symbol = ibus_text_new_from_static_string ("");
     }
     else {
-        prop->priv->symbol = g_object_ref_sink (symbol);
+        prop->priv->symbol = symbol;
     }
+
+    g_object_ref_sink (prop->priv->symbol);
 }
 
 void
@@ -615,7 +616,7 @@ ibus_property_set_tooltip (IBusProperty *prop,
     g_assert (IBUS_IS_PROPERTY (prop));
     g_assert (tooltip == NULL || IBUS_IS_TEXT (tooltip));
 
-    if (prop->priv->tooltip && !ibus_text_get_is_static (prop->priv->tooltip)) {
+    if (prop->priv->tooltip) {
         g_object_unref (prop->priv->tooltip);
     }
 
@@ -624,8 +625,9 @@ ibus_property_set_tooltip (IBusProperty *prop,
     }
     else {
         prop->priv->tooltip = tooltip;
-        g_object_ref_sink (prop->priv->tooltip);
     }
+
+    g_object_ref_sink (prop->priv->tooltip);
 }
 
 void