From 7152bfd5772f64ec0fc7d7d204f5fd4986104823 Mon Sep 17 00:00:00 2001
From: Jesse Luehrs <doy@tozt.net>
Date: Sat, 7 Dec 2019 02:53:54 -0500
Subject: one more try for leaving a cursor at the end of a row

---
 src/grid.rs                             | 32 ++++++++++++++++++--------------
 src/term.rs                             | 28 +++++++++++++++++++---------
 tests/data/fixtures/il_dl.in            |  1 +
 tests/data/fixtures/il_dl/18.json       | 12 ++++++++++++
 tests/data/fixtures/il_dl/18.typescript |  2 ++
 5 files changed, 52 insertions(+), 23 deletions(-)
 create mode 100644 tests/data/fixtures/il_dl/18.json
 create mode 100644 tests/data/fixtures/il_dl/18.typescript

diff --git a/src/grid.rs b/src/grid.rs
index b12216c..88c33eb 100644
--- a/src/grid.rs
+++ b/src/grid.rs
@@ -274,18 +274,20 @@ impl Grid {
                 }
 
                 // this can happen if you get the cursor off the end of a row,
-                // and then do something to clear the current row without
-                // moving the cursor (IL, ED, EL, etc). i can't see any way
-                // for this to happen without the entire current row being
-                // cleared (not just the last cell), so this seems
-                // prooooobably fine?
+                // and then do something to clear the end of the current row
+                // without moving the cursor (IL, DL, ED, EL, etc). we know
+                // there can't be something in the last column because we
+                // would have caught that above, so it should be safe to
+                // overwrite it.
                 if !found {
                     pos.row = orig_row;
                     crate::term::MoveFromTo::new(prev_pos, pos)
                         .write_buf(contents);
                     contents.push(b' ');
-                    crate::term::ClearRowBackward::default()
-                        .write_buf(contents);
+                    crate::term::SaveCursor::default().write_buf(contents);
+                    crate::term::Backspace::default().write_buf(contents);
+                    crate::term::EraseChar::new(1).write_buf(contents);
+                    crate::term::RestoreCursor::default().write_buf(contents);
                 }
             }
         } else {
@@ -374,18 +376,20 @@ impl Grid {
                 }
 
                 // this can happen if you get the cursor off the end of a row,
-                // and then do something to clear the current row without
-                // moving the cursor (IL, ED, EL, etc). i can't see any way
-                // for this to happen without the entire current row being
-                // cleared (not just the last cell), so this seems
-                // prooooobably fine?
+                // and then do something to clear the end of the current row
+                // without moving the cursor (IL, DL, ED, EL, etc). we know
+                // there can't be something in the last column because we
+                // would have caught that above, so it should be safe to
+                // overwrite it.
                 if !found {
                     pos.row = orig_row;
                     crate::term::MoveFromTo::new(prev_pos, pos)
                         .write_buf(contents);
                     contents.push(b' ');
-                    crate::term::ClearRowBackward::default()
-                        .write_buf(contents);
+                    crate::term::SaveCursor::default().write_buf(contents);
+                    crate::term::Backspace::default().write_buf(contents);
+                    crate::term::EraseChar::new(1).write_buf(contents);
+                    crate::term::RestoreCursor::default().write_buf(contents);
                 }
             }
         } else {
diff --git a/src/term.rs b/src/term.rs
index 0a578c1..31e1f51 100644
--- a/src/term.rs
+++ b/src/term.rs
@@ -26,31 +26,41 @@ impl BufWrite for ClearRowForward {
 
 #[derive(Default, Debug)]
 #[must_use = "this struct does nothing unless you call write_buf"]
-pub struct ClearRowBackward;
+pub struct CRLF;
 
-impl BufWrite for ClearRowBackward {
+impl BufWrite for CRLF {
     fn write_buf(&self, buf: &mut Vec<u8>) {
-        buf.extend_from_slice(b"\x1b[1K");
+        buf.extend_from_slice(b"\r\n");
     }
 }
 
 #[derive(Default, Debug)]
 #[must_use = "this struct does nothing unless you call write_buf"]
-pub struct CRLF;
+pub struct Backspace;
 
-impl BufWrite for CRLF {
+impl BufWrite for Backspace {
     fn write_buf(&self, buf: &mut Vec<u8>) {
-        buf.extend_from_slice(b"\r\n");
+        buf.extend_from_slice(b"\x08");
     }
 }
 
 #[derive(Default, Debug)]
 #[must_use = "this struct does nothing unless you call write_buf"]
-pub struct Backspace;
+pub struct SaveCursor;
 
-impl BufWrite for Backspace {
+impl BufWrite for SaveCursor {
     fn write_buf(&self, buf: &mut Vec<u8>) {
-        buf.extend_from_slice(b"\x08");
+        buf.extend_from_slice(b"\x1b7");
+    }
+}
+
+#[derive(Default, Debug)]
+#[must_use = "this struct does nothing unless you call write_buf"]
+pub struct RestoreCursor;
+
+impl BufWrite for RestoreCursor {
+    fn write_buf(&self, buf: &mut Vec<u8>) {
+        buf.extend_from_slice(b"\x1b8");
     }
 }
 
diff --git a/tests/data/fixtures/il_dl.in b/tests/data/fixtures/il_dl.in
index 3e159aa..db55d5e 100644
--- a/tests/data/fixtures/il_dl.in
+++ b/tests/data/fixtures/il_dl.in
@@ -15,3 +15,4 @@ a
 b
 \x1b[L
 cd
+\x1bc\na\x1b[1;80Hb\x1b[M
diff --git a/tests/data/fixtures/il_dl/18.json b/tests/data/fixtures/il_dl/18.json
new file mode 100644
index 0000000..131a334
--- /dev/null
+++ b/tests/data/fixtures/il_dl/18.json
@@ -0,0 +1,12 @@
+{
+  "contents": "a",
+  "cells": {
+    "0,0": {
+      "contents": "a"
+    }
+  },
+  "cursor_position": [
+    0,
+    80
+  ]
+}
\ No newline at end of file
diff --git a/tests/data/fixtures/il_dl/18.typescript b/tests/data/fixtures/il_dl/18.typescript
new file mode 100644
index 0000000..607e0b1
--- /dev/null
+++ b/tests/data/fixtures/il_dl/18.typescript
@@ -0,0 +1,2 @@
+c
+ab
\ No newline at end of file
-- 
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