[vte] widget: Limit bell rate

[Christian Persch <chpe src gnome org>]

commit 5c94130ec7a8f9bb5eb38db7c7fe384c9699a199
Author: Christian Persch <chpe src gnome org>
Date:   Sat Mar 3 18:32:44 2018 +0100

    widget: Limit bell rate
    
    Also move the gdk_display_beep() and the signal emission out
    of the processing loop and just queue it.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=790815

 src/vte.cc         |   12 ++++++++++++
 src/vtedefines.hh  |    3 +++
 src/vteinternal.hh |    4 ++++
 src/vteseq.cc      |    3 +--
 4 files changed, 20 insertions(+), 2 deletions(-)
---
diff --git a/src/vte.cc b/src/vte.cc
index cfa8a19..57aa197 100644
--- a/src/vte.cc
+++ b/src/vte.cc
@@ -10648,6 +10648,8 @@ VteTerminalPrivate::reset(bool clear_tabstops,
         GObject *object = G_OBJECT(m_terminal);
         g_object_freeze_notify(object);
 
+        m_bell_pending = false;
+
        /* Clear the output buffer. */
        _vte_byte_array_clear(m_outgoing);
        /* Reset charset substitution state. */
@@ -11078,6 +11080,16 @@ VteTerminalPrivate::emit_pending_signals()
                g_signal_emit(m_terminal, signals[SIGNAL_CONTENTS_CHANGED], 0);
                m_contents_changed_pending = false;
        }
+        if (m_bell_pending) {
+                auto const timestamp = g_get_monotonic_time();
+                if ((timestamp - m_bell_timestamp) >= VTE_BELL_MINIMUM_TIME_DIFFERENCE) {
+                        beep();
+                        emit_bell();
+                }
+
+                m_bell_timestamp = timestamp;
+                m_bell_pending = false;
+        }
 
         g_object_thaw_notify(object);
 }
diff --git a/src/vtedefines.hh b/src/vtedefines.hh
index 115081b..e8ffb62 100644
--- a/src/vtedefines.hh
+++ b/src/vtedefines.hh
@@ -109,6 +109,9 @@
 #define VTE_CELL_SCALE_MIN (1.)
 #define VTE_CELL_SCALE_MAX (2.)
 
+/* Minimum time between two beeps (µs) */
+#define VTE_BELL_MINIMUM_TIME_DIFFERENCE (100000)
+
 /* Maximum length of a URI in the OSC 8 escape sequences. There's no de jure limit,
  * 2000-ish the de facto standard, and Internet Explorer supports 2083.
  * See also the comment of VTE_HYPERLINK_TOTAL_LENGTH_MAX. */
diff --git a/src/vteinternal.hh b/src/vteinternal.hh
index fe63e76..ba8bd10 100644
--- a/src/vteinternal.hh
+++ b/src/vteinternal.hh
@@ -648,6 +648,10 @@ public:
        /* Background */
         double m_background_alpha;
 
+        /* Bell */
+        int64_t m_bell_timestamp;
+        bool m_bell_pending{false};
+
        /* Key modifiers. */
         guint m_modifiers;
 
diff --git a/src/vteseq.cc b/src/vteseq.cc
index fd3227f..4da48c4 100644
--- a/src/vteseq.cc
+++ b/src/vteseq.cc
@@ -927,8 +927,7 @@ VteTerminalPrivate::seq_shift_out(vte::parser::Params const& params)
 void
 VteTerminalPrivate::seq_bell(vte::parser::Params const& params)
 {
-        beep();
-        emit_bell();
+        m_bell_pending = true;
 }
 
 /* Backtab. */