[gtk+/gtk-3-16] multipress: Only emit preedit signals if needed

[Matthias Clasen <matthiasc src gnome org>]

commit cf2a41cb5247fa7bc8cbfbf28a673a40a39ea3d2
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Aug 18 15:42:56 2015 -0400

    multipress: Only emit preedit signals if needed
    
    When clearing the compose buffer, don't emit preedit-changed
    unconditionally. This triggers a recursion which leads to
    a crash.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=753644

 modules/input/gtkimcontextmultipress.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)
---
diff --git a/modules/input/gtkimcontextmultipress.c b/modules/input/gtkimcontextmultipress.c
index 9cfe028..b92570b 100644
--- a/modules/input/gtkimcontextmultipress.c
+++ b/modules/input/gtkimcontextmultipress.c
@@ -170,11 +170,14 @@ clear_compose_buffer (GtkImContextMultipress *multipress_context)
   multipress_context->key_last_entered = 0;
   multipress_context->compose_count = 0;
 
-  multipress_context->tentative_match = NULL;
   cancel_automatic_timeout_commit (multipress_context);
 
-  g_signal_emit_by_name (multipress_context, "preedit-changed");
-  g_signal_emit_by_name (multipress_context, "preedit-end");
+  if (multipress_context->tentative_match)
+    {
+      multipress_context->tentative_match = NULL;
+      g_signal_emit_by_name (multipress_context, "preedit-changed");
+      g_signal_emit_by_name (multipress_context, "preedit-end");
+    }
 }
 
 /* Finish composing, provide the character, and clear our compose buffer.