[vte/wip/rishi/precmd-preexec: 1/4] Support preexec notifications from an interactive shell

[Debarshi Ray <debarshir src gnome org>]

commit 0924f742c448fb5a585b4b2edc451667227d5874
Author: Debarshi Ray <debarshir gnome org>
Date:   Wed Jan 7 16:01:00 2015 +0100

    Support preexec notifications from an interactive shell
    
    Add sequences
      OSC 777 ; preexec BEL
      OSC 777 ; preexec ST
    
    that can be used from an interactive shell's preexec hook to notify
    the terminal emulator that a new command is about to be executed.
    Examples of such hooks are Bash's PS0 and Zsh's preexec.
    
    The OSC 777 escape sequence is taken from Enlightenment's Terminology:
    https://phab.enlightenment.org/T1765
    
    https://bugzilla.gnome.org/show_bug.cgi?id=711059
    https://bugzilla.gnome.org/show_bug.cgi?id=711060

 src/vte.cc            |    7 +++++++
 src/vte.sh            |    2 +-
 src/vte/vteterminal.h |    4 +++-
 src/vtegtk.cc         |   18 ++++++++++++++++++
 src/vtegtk.hh         |    1 +
 src/vteinternal.hh    |    5 +++++
 src/vteseq.cc         |   19 ++++++++++++++++++-
 7 files changed, 53 insertions(+), 3 deletions(-)
---
diff --git a/src/vte.cc b/src/vte.cc
index 2a76632..1a7b533 100644
--- a/src/vte.cc
+++ b/src/vte.cc
@@ -10762,6 +10762,13 @@ VteTerminalPrivate::emit_pending_signals()
 
        emit_adjustment_changed();
 
+        if (m_shell_preexec) {
+                _vte_debug_print (VTE_DEBUG_SIGNALS,
+                                  "Emitting `shell-preexec'.\n");
+                g_signal_emit(object, signals[SIGNAL_SHELL_PREEXEC], 0);
+                m_shell_preexec = FALSE;
+        }
+
        if (m_window_title_changed) {
                 if (m_window_title != m_window_title_pending) {
                         m_window_title.swap(m_window_title_pending);
diff --git a/src/vte.sh b/src/vte.sh
index 5fb1699..4ade59d 100644
--- a/src/vte.sh
+++ b/src/vte.sh
@@ -57,7 +57,7 @@ __vte_prompt_command() {
 
 case "$TERM" in
   xterm*|vte*)
-    [ -n "$BASH_VERSION" ] && PROMPT_COMMAND="__vte_prompt_command"
+    [ -n "$BASH_VERSION" ] && PROMPT_COMMAND="__vte_prompt_command" && PS0=$(printf 
"\u009D777;preexec\u009C")
     [ -n "$ZSH_VERSION"  ] && precmd_functions+=(__vte_osc7)
     ;;
 esac
diff --git a/src/vte/vteterminal.h b/src/vte/vteterminal.h
index 8c493bc..5f3d325 100644
--- a/src/vte/vteterminal.h
+++ b/src/vte/vteterminal.h
@@ -104,8 +104,10 @@ struct _VteTerminalClass {
 
        void (*bell)(VteTerminal* terminal);
 
+       void (*shell_preexec)(VteTerminal* terminal);
+
         /* Padding for future expansion. */
-        gpointer padding[16];
+        gpointer padding[15];
 
         VteTerminalClassPrivate *priv;
 };
diff --git a/src/vtegtk.cc b/src/vtegtk.cc
index 4d74b21..1e5282c 100644
--- a/src/vtegtk.cc
+++ b/src/vtegtk.cc
@@ -700,6 +700,7 @@ vte_terminal_class_init(VteTerminalClass *klass)
        klass->child_exited = NULL;
        klass->encoding_changed = NULL;
        klass->char_size_changed = NULL;
+       klass->shell_preexec = NULL;
        klass->window_title_changed = NULL;
        klass->icon_title_changed = NULL;
        klass->selection_changed = NULL;
@@ -776,6 +777,23 @@ vte_terminal_class_init(VteTerminalClass *klass)
                              1, G_TYPE_INT);
 
         /**
+         * VteTerminal::shell-preexec:
+         * @vteterminal: the object which received the signal
+         *
+         * Emitted when the interactive shell has read in a complete
+         * command and is about to execute it.
+         */
+        signals[SIGNAL_SHELL_PREEXEC] =
+                g_signal_new(I_("shell-preexec"),
+                             G_OBJECT_CLASS_TYPE(klass),
+                             G_SIGNAL_RUN_LAST,
+                             G_STRUCT_OFFSET(VteTerminalClass, shell_preexec),
+                             NULL,
+                             NULL,
+                             g_cclosure_marshal_VOID__VOID,
+                             G_TYPE_NONE, 0);
+
+        /**
          * VteTerminal::window-title-changed:
          * @vteterminal: the object which received the signal
          *
diff --git a/src/vtegtk.hh b/src/vtegtk.hh
index c49754e..cb7b02f 100644
--- a/src/vtegtk.hh
+++ b/src/vtegtk.hh
@@ -52,6 +52,7 @@ enum {
         SIGNAL_RESIZE_WINDOW,
         SIGNAL_RESTORE_WINDOW,
         SIGNAL_SELECTION_CHANGED,
+        SIGNAL_SHELL_PREEXEC,
         SIGNAL_TEXT_DELETED,
         SIGNAL_TEXT_INSERTED,
         SIGNAL_TEXT_MODIFIED,
diff --git a/src/vteinternal.hh b/src/vteinternal.hh
index 737678a..1c1db50 100644
--- a/src/vteinternal.hh
+++ b/src/vteinternal.hh
@@ -572,6 +572,8 @@ public:
         gboolean m_cursor_moved_pending;
         gboolean m_contents_changed_pending;
 
+        gboolean m_shell_preexec;
+
         std::string m_window_title{};
         std::string m_current_directory_uri{};
         std::string m_current_file_uri{};
@@ -1315,6 +1317,9 @@ public:
                              int osc) noexcept;
 
         /* OSC handlers */
+        void handle_urxvt_extension(vte::parser::Sequence const& seq,
+                                    vte::parser::StringTokeniser::const_iterator& token,
+                                    vte::parser::StringTokeniser::const_iterator const& endtoken) noexcept;
         void set_color(vte::parser::Sequence const& seq,
                        vte::parser::StringTokeniser::const_iterator& token,
                        vte::parser::StringTokeniser::const_iterator const& endtoken,
diff --git a/src/vteseq.cc b/src/vteseq.cc
index ba97480..5c6492a 100644
--- a/src/vteseq.cc
+++ b/src/vteseq.cc
@@ -1339,6 +1339,20 @@ VteTerminalPrivate::delete_lines(vte::grid::row_t param)
         m_text_deleted_flag = TRUE;
 }
 
+void
+VteTerminalPrivate::handle_urxvt_extension(vte::parser::Sequence const& seq,
+                                           vte::parser::StringTokeniser::const_iterator& token,
+                                           vte::parser::StringTokeniser::const_iterator const& endtoken) 
noexcept
+{
+        if (token == endtoken) {
+                return;
+        }
+
+        if (*token == "preexec") {
+                m_shell_preexec = TRUE;
+        }
+}
+
 bool
 VteTerminalPrivate::get_osc_color_index(int osc,
                                         int value,
@@ -6342,6 +6356,10 @@ VteTerminalPrivate::OSC(vte::parser::Sequence const& seq)
                 reset_color(VTE_HIGHLIGHT_FG, VTE_COLOR_SOURCE_ESCAPE);
                 break;
 
+        case VTE_OSC_URXVT_EXTENSION:
+                handle_urxvt_extension(seq, it, cend);
+                break;
+
         case VTE_OSC_XTERM_SET_ICON_TITLE:
         case VTE_OSC_XTERM_SET_XPROPERTY:
         case VTE_OSC_XTERM_SET_COLOR_MOUSE_CURSOR_FG:
@@ -6382,7 +6400,6 @@ VteTerminalPrivate::OSC(vte::parser::Sequence const& seq)
         case VTE_OSC_URXVT_SET_FONT_BOLD_ITALIC:
         case VTE_OSC_URXVT_VIEW_UP:
         case VTE_OSC_URXVT_VIEW_DOWN:
-        case VTE_OSC_URXVT_EXTENSION:
         case VTE_OSC_YF_RQGWR:
         default:
                 break;