From 197819db6dab174c1bdd6e1481e71253171b45c1 Mon Sep 17 00:00:00 2001
From: Wez Furlong <wez@wezfurlong.org>
Date: Fri, 9 Mar 2018 22:15:06 -0800
Subject: [PATCH] Add basic support for ICH which is used by bash CTRL-R

---
 term/src/csi.rs           |  6 ++++++
 term/src/screen.rs        |  8 ++++++++
 term/src/terminalstate.rs | 14 ++++++++++++++
 term/src/test/csi.rs      | 14 ++++++++++++++
 4 files changed, 42 insertions(+)

diff --git a/term/src/csi.rs b/term/src/csi.rs
index 0b3f9b01c..3f5e653ea 100644
--- a/term/src/csi.rs
+++ b/term/src/csi.rs
@@ -59,6 +59,7 @@ pub enum CSIAction {
     SoftReset,
     EraseCharacter(i64),
     DeleteCharacter(i64),
+    InsertCharacter(i64),
 }
 
 /// Constrol Sequence Initiator (CSI) Parser.
@@ -430,6 +431,11 @@ impl<'a> Iterator for CSIParser<'a> {
         #[cfg_attr(feature = "cargo-clippy", allow(match_same_arms))]
         match (self.byte, self.intermediates, params) {
             (_, _, None) => None,
+
+            // ICH: Insert Character
+            ('@', &[], Some(&[])) => Some(CSIAction::InsertCharacter(1)),
+            ('@', &[], Some(&[n])) => Some(CSIAction::InsertCharacter(n)),
+
             // CUU - Cursor Up n times
             ('A', &[], Some(&[])) => Some(CSIAction::SetCursorXY {
                 x: Position::Relative(0),
diff --git a/term/src/screen.rs b/term/src/screen.rs
index 3514ffaf8..e0b5ea59c 100644
--- a/term/src/screen.rs
+++ b/term/src/screen.rs
@@ -100,9 +100,17 @@ impl Screen {
         self.lines.iter().map(|l| l.clone()).collect()
     }
 
+    pub fn insert_cell(&mut self, x: usize, y: VisibleRowIndex) {
+        let line_idx = self.phys_row(y);
+        let line = self.line_mut(line_idx);
+        line.invalidate_implicit_links();
+        line.cells.insert(x, Cell::default());
+    }
+
     pub fn erase_cell(&mut self, x: usize, y: VisibleRowIndex) {
         let line_idx = self.phys_row(y);
         let line = self.line_mut(line_idx);
+        line.invalidate_implicit_links();
         line.cells.remove(x);
         line.cells.push(Cell::default());
     }
diff --git a/term/src/terminalstate.rs b/term/src/terminalstate.rs
index 611d4b329..735989346 100644
--- a/term/src/terminalstate.rs
+++ b/term/src/terminalstate.rs
@@ -1034,6 +1034,20 @@ impl TerminalState {
                 }
                 self.clear_selection_if_intersects(x..limit, y as ScrollbackOrVisibleRowIndex);
             }
+            CSIAction::InsertCharacter(n) => {
+                let y = self.cursor.y;
+                let x = self.cursor.x;
+                // TODO: this limiting behavior may not be correct.  There's also a
+                // SEM sequence that impacts the scope of ICH and ECH to consider.
+                let limit = (x + n as usize).min(self.screen().physical_cols);
+                {
+                    let screen = self.screen_mut();
+                    for x in x..limit as usize {
+                        screen.insert_cell(x, y);
+                    }
+                }
+                self.clear_selection_if_intersects(x..limit, y as ScrollbackOrVisibleRowIndex);
+            }
             CSIAction::EraseCharacter(n) => {
                 let y = self.cursor.y;
                 let x = self.cursor.x;
diff --git a/term/src/test/csi.rs b/term/src/test/csi.rs
index 6ae8ceb52..c5868444f 100644
--- a/term/src/test/csi.rs
+++ b/term/src/test/csi.rs
@@ -19,6 +19,20 @@ fn test_vpa() {
     term.assert_cursor_pos(0, 1, None);
 }
 
+#[test]
+fn test_ich() {
+    let mut term = TestTerm::new(3, 4, 0);
+    term.print("hey!wat?");
+    term.cup(1, 0);
+    term.print("\x1b[2@");
+    assert_visible_contents(&term, &["h  ey!", "wat?", "    "]);
+    // check how we handle overflowing the width
+    term.print("\x1b[12@");
+    assert_visible_contents(&term, &["h     ey!", "wat?", "    "]);
+    term.print("\x1b[-12@");
+    assert_visible_contents(&term, &["h     ey!", "wat?", "    "]);
+}
+
 #[test]
 fn test_ech() {
     let mut term = TestTerm::new(3, 4, 0);