From 25e2dc2a9690d9d285ab5495a4da558abb08e50e Mon Sep 17 00:00:00 2001
From: Wez Furlong <wez@wezfurlong.org>
Date: Mon, 19 Feb 2018 16:26:10 -0800
Subject: [PATCH] fix an issue with the selection when in scrollback

---
 term/src/terminalstate.rs  | 25 ++++++++++++-------------
 term/src/test/mod.rs       | 28 ++++++++++++++++++++++++++++
 term/src/test/selection.rs | 24 ++++++++++++++++++++++++
 3 files changed, 64 insertions(+), 13 deletions(-)

diff --git a/term/src/terminalstate.rs b/term/src/terminalstate.rs
index 567d75f33..e054f1845 100644
--- a/term/src/terminalstate.rs
+++ b/term/src/terminalstate.rs
@@ -90,7 +90,7 @@ pub struct TerminalState {
     /// purely for display purposes.
     /// The offset is measured from the top of the physical viewable
     /// screen with larger numbers going backwards.
-    viewport_offset: VisibleRowIndex,
+    pub(crate) viewport_offset: VisibleRowIndex,
 
     /// Remembers the starting coordinate of the selection prior to
     /// dragging.
@@ -281,13 +281,15 @@ impl TerminalState {
                             self.selection_range = None;
                             self.selection_start = Some(SelectionCoordinate {
                                 x: event.x,
-                                y: event.y as ScrollbackOrVisibleRowIndex,
+                                y: event.y as ScrollbackOrVisibleRowIndex -
+                                    self.viewport_offset as ScrollbackOrVisibleRowIndex,
                             });
                             host.set_clipboard(None)?;
                         }
                         // Double click to select a word on the current line
                         Some(&LastMouseClick { streak: 2, .. }) => {
-                            let y = event.y as ScrollbackOrVisibleRowIndex;
+                            let y = event.y as ScrollbackOrVisibleRowIndex -
+                                self.viewport_offset as ScrollbackOrVisibleRowIndex;
                             let idx = self.screen().scrollback_or_visible_row(y);
                             let line = self.screen().lines[idx].as_str();
                             use unicode_segmentation::UnicodeSegmentation;
@@ -324,18 +326,14 @@ impl TerminalState {
                         }
                         // triple click to select the current line
                         Some(&LastMouseClick { streak: 3, .. }) => {
-                            self.selection_start = Some(SelectionCoordinate {
-                                x: event.x,
-                                y: event.y as ScrollbackOrVisibleRowIndex,
-                            });
+                            let y = event.y as ScrollbackOrVisibleRowIndex -
+                                self.viewport_offset as ScrollbackOrVisibleRowIndex;
+                            self.selection_start = Some(SelectionCoordinate { x: event.x, y });
                             self.selection_range = Some(SelectionRange {
-                                start: SelectionCoordinate {
-                                    x: 0,
-                                    y: event.y as ScrollbackOrVisibleRowIndex,
-                                },
+                                start: SelectionCoordinate { x: 0, y },
                                 end: SelectionCoordinate {
                                     x: usize::max_value(),
-                                    y: event.y as ScrollbackOrVisibleRowIndex,
+                                    y,
                                 },
                             });
                             self.dirty_selection_lines();
@@ -395,7 +393,8 @@ impl TerminalState {
                     self.dirty_selection_lines();
                     let end = SelectionCoordinate {
                         x: event.x,
-                        y: event.y as ScrollbackOrVisibleRowIndex,
+                        y: event.y as ScrollbackOrVisibleRowIndex -
+                            self.viewport_offset as ScrollbackOrVisibleRowIndex,
                     };
                     let sel = match self.selection_range.take() {
                         None => {
diff --git a/term/src/test/mod.rs b/term/src/test/mod.rs
index 6afd8f574..79be56add 100644
--- a/term/src/test/mod.rs
+++ b/term/src/test/mod.rs
@@ -204,6 +204,34 @@ impl TestTerm {
             reason
         );
     }
+
+    fn viewport_lines(&self) -> Vec<Line> {
+        let screen = self.screen();
+        let line_count = screen.lines.len();
+        let viewport = self.viewport_offset;
+        let phs_rows = screen.physical_rows;
+        screen
+            .all_lines()
+            .iter()
+            .skip((line_count as i64 - phs_rows as i64 - viewport) as usize)
+            .take(phs_rows)
+            .cloned()
+            .collect()
+    }
+    fn print_viewport_lines(&self) {
+        println!("viewport contents are:");
+        for line in self.viewport_lines() {
+            println!("[{}]", line.as_str());
+        }
+    }
+
+    fn assert_viewport_contents(&self, expect_lines: &[&str]) {
+        self.print_viewport_lines();
+
+        let expect: Vec<Line> = expect_lines.iter().map(|s| (*s).into()).collect();
+
+        assert_lines_equal(&self.viewport_lines(), &expect, Compare::TEXT);
+    }
 }
 
 impl Deref for TestTerm {
diff --git a/term/src/test/selection.rs b/term/src/test/selection.rs
index 4c1e4cacf..2dd91ff05 100644
--- a/term/src/test/selection.rs
+++ b/term/src/test/selection.rs
@@ -62,3 +62,27 @@ fn triple_click_selection() {
 
     assert_eq!(term.get_clipboard().unwrap(), "hello worl");
 }
+
+/// Make sure that we adjust for the viewport offset when scrolling
+#[test]
+fn selection_in_scrollback() {
+    let mut term = TestTerm::new(2, 1, 4);
+    term.print("1234");
+    assert_all_contents(&term, &["1", "2", "3", "4"]);
+
+    // Scroll back one line
+    term.scroll_viewport(-1);
+    term.assert_viewport_contents(&["2", "3"]);
+
+    term.click_n(0, 0, MouseButton::Left, 2);
+    assert_eq!(term.get_clipboard().unwrap(), "2");
+
+    // Clear the click streak
+    term.click_n(0, 1, MouseButton::Right, 1);
+
+    term.click_n(0, 1, MouseButton::Left, 3);
+    assert_eq!(term.get_clipboard().unwrap(), "3");
+
+    term.drag_select(0, 0, 0, 1);
+    assert_eq!(term.get_clipboard().unwrap(), "2\n3");
+}