From 98d83fbd3c9cc25d44757ef1a844a7e6ccd4be5b Mon Sep 17 00:00:00 2001
From: Debarshi Ray <debarshir@gnome.org>
Date: Sun, 26 Nov 2023 18:24:11 -0800
Subject: [PATCH 4/9] 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            |  6 ++++++
 src/vte.sh.in         |  3 ++-
 src/vte/vteterminal.h |  3 ++-
 src/vtegtk.cc         | 18 ++++++++++++++++++
 src/vtegtk.hh         |  1 +
 src/vteinternal.hh    |  1 +
 src/vteseq.cc         |  4 ++++
 7 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/src/vte.cc b/src/vte.cc
index c7981e1b..49a3d8f3 100644
--- a/src/vte.cc
+++ b/src/vte.cc
@@ -10774,6 +10774,12 @@ Terminal::emit_pending_signals()
                               m_notification_summary.c_str(),
                               m_notification_body.c_str());
         }
+
+        if (m_pending_changes & vte::to_integral(PendingChanges::SHELL_PREEXEC)) {
+                _vte_debug_print (VTE_DEBUG_SIGNALS,
+                                  "Emitting `shell-preexec'.\n");
+                g_signal_emit(freezer.get(), signals[SIGNAL_SHELL_PREEXEC], 0);
+        }
 #endif
 
 	if (m_pending_changes & vte::to_integral(PendingChanges::TITLE)) {
diff --git a/src/vte.sh.in b/src/vte.sh.in
index 50242223..fbbb1a03 100644
--- a/src/vte.sh.in
+++ b/src/vte.sh.in
@@ -51,9 +51,10 @@ if [[ -n "${BASH_VERSION:-}" ]]; then
     # use the __vte_prompt_command function which also sets the title.
 
     if [[ "$(declare -p PROMPT_COMMAND 2>&1)" =~ "declare -a" ]]; then
-	PROMPT_COMMAND+=(__vte_osc7)
+	PROMPT_COMMAND+=(__vte_osc7) && PS0=$(printf "\033]777;preexec\033\\")
     else
 	PROMPT_COMMAND="__vte_prompt_command"
+	PROMPT_COMMAND="__vte_prompt_command" && PS0=$(printf "\033]777;preexec\033\\")
     fi
 
 elif [[ -n "${ZSH_VERSION:-}" ]]; then
diff --git a/src/vte/vteterminal.h b/src/vte/vteterminal.h
index 77d96a31..29529020 100644
--- a/src/vte/vteterminal.h
+++ b/src/vte/vteterminal.h
@@ -115,10 +115,11 @@ struct _VteTerminalClass {
 
 #if _VTE_GTK == 3
         void (*notification_received)(VteTerminal* terminal, const gchar *summary, const gchar *body);
+        void (*shell_preexec)(VteTerminal* terminal);
 
         /* Compatibility padding due to fedora patches intruding on our ABI */
         /*< private >*/
-        gpointer _extra_padding[2];
+        gpointer _extra_padding[1];
 #endif /* _VTE_GTK == 3 */
 
         void (*setup_context_menu)(VteTerminal* terminal,
diff --git a/src/vtegtk.cc b/src/vtegtk.cc
index c924df55..c4cf5537 100644
--- a/src/vtegtk.cc
+++ b/src/vtegtk.cc
@@ -1347,6 +1347,7 @@ vte_terminal_class_init(VteTerminalClass *klass)
 	klass->char_size_changed = NULL;
 #if _VTE_GTK == 3
 	klass->notification_received = NULL;
+	klass->shell_preexec = NULL;
 #endif
 	klass->window_title_changed = NULL;
 	klass->icon_title_changed = NULL;
@@ -1451,6 +1452,23 @@ vte_terminal_class_init(VteTerminalClass *klass)
                              _vte_marshal_VOID__STRING_STRING,
                              G_TYPE_NONE,
                              2, G_TYPE_STRING, G_TYPE_STRING);
+
+        /**
+         * 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);
 #endif
 
         /**
diff --git a/src/vtegtk.hh b/src/vtegtk.hh
index e811bd1c..4e400cd3 100644
--- a/src/vtegtk.hh
+++ b/src/vtegtk.hh
@@ -54,6 +54,7 @@ enum {
         SIGNAL_SELECTION_CHANGED,
         SIGNAL_SETUP_CONTEXT_MENU,
 #if _VTE_GTK == 3
+        SIGNAL_SHELL_PREEXEC,
         SIGNAL_NOTIFICATION_RECEIVED,
 #endif
         SIGNAL_WINDOW_TITLE_CHANGED,
diff --git a/src/vteinternal.hh b/src/vteinternal.hh
index cb4f00bb..0479ae0e 100644
--- a/src/vteinternal.hh
+++ b/src/vteinternal.hh
@@ -757,6 +757,7 @@ public:
                 CWF   = 1u << 2,
 #if _VTE_GTK == 3
                 NOTIFICATION = 1u << 3,
+                SHELL_PREEXEC = 1u << 4,
 #endif
         };
         unsigned m_pending_changes{0};
diff --git a/src/vteseq.cc b/src/vteseq.cc
index 97e2c5f8..92d1f857 100644
--- a/src/vteseq.cc
+++ b/src/vteseq.cc
@@ -1325,6 +1325,10 @@ Terminal::handle_urxvt_extension(vte::parser::Sequence const& seq,
                 m_notification_body = *token;
                 return;
         }
+
+        if (*token == "preexec") {
+                m_pending_changes |= vte::to_integral(PendingChanges::SHELL_PREEXEC);
+        }
 }
 #endif
 
-- 
2.43.0