Do not return beginning of buffer whenever display to buffer coord fails

Use an empty Optional to show that resolution failed and just do not
do anything in the mouse event handler in that case.

1 files changed, 21 insertions, 11 deletions

diff --git a/src/input_handler.cc b/src/input_handler.cc
index 0693bc43..6c6439bb 100644
--- a/src/input_handler.cc
+++ b/src/input_handler.cc
@@ -116,7 +116,6 @@ struct MouseHandler
             return false;
 
         Buffer& buffer = context.buffer();
-        BufferCoord cursor;
         // bits above these potentially store additional information
         constexpr auto mask = (Key::Modifiers) 0x7FF;
         constexpr auto modifiers = Key::Modifiers::Control | Key::Modifiers::Alt | Key::Modifiers::Shift | Key::Modifiers::MouseButtonMask | ~mask;
@@ -128,20 +127,31 @@ struct MouseHandler
             {
             case Key::MouseButton::Right: {
                 m_dragging.reset();
-                cursor = context.window().buffer_coord(key.coord());
+                auto cursor = context.window().buffer_coord(key.coord());
+                if (not cursor)
+                {
+                    context.ensure_cursor_visible = false;
+                    return true;
+                }
                 ScopedSelectionEdition selection_edition{context};
                 auto& selections = context.selections();
                 if (key.modifiers & Key::Modifiers::Control)
-                    selections = {{selections.begin()->anchor(), cursor}};
+                    selections = {{selections.begin()->anchor(), *cursor}};
                 else
-                    selections.main() = {selections.main().anchor(), cursor};
+                    selections.main() = {selections.main().anchor(), *cursor};
                 selections.sort_and_merge_overlapping();
                 return true;
             }
 
             case Key::MouseButton::Left: {
                 m_dragging.reset(new ScopedSelectionEdition{context});
-                m_anchor = context.window().buffer_coord(key.coord());
+                auto anchor = context.window().buffer_coord(key.coord());
+                if (not anchor)
+                {
+                    context.ensure_cursor_visible = false;
+                    return true;
+                }
+                m_anchor = *anchor;
                 if (not (key.modifiers & Key::Modifiers::Control))
                     context.selections_write_only() = { buffer, m_anchor};
                 else
@@ -159,28 +169,28 @@ struct MouseHandler
             }
 
         case Key::Modifiers::MouseRelease: {
-            if (not m_dragging)
+            auto cursor = context.window().buffer_coord(key.coord());
+            if (not m_dragging or not cursor)
             {
                 context.ensure_cursor_visible = false;
                 return true;
             }
             auto& selections = context.selections();
-            cursor = context.window().buffer_coord(key.coord());
-            selections.main() = {buffer.clamp(m_anchor), cursor};
+            selections.main() = {buffer.clamp(m_anchor), *cursor};
             selections.sort_and_merge_overlapping();
             m_dragging.reset();
             return true;
         }
 
         case Key::Modifiers::MousePos: {
-            if (not m_dragging)
+            auto cursor = context.window().buffer_coord(key.coord());
+            if (not m_dragging or not cursor)
             {
                 context.ensure_cursor_visible = false;
                 return true;
             }
-            cursor = context.window().buffer_coord(key.coord());
             auto& selections = context.selections();
-            selections.main() = {buffer.clamp(m_anchor), cursor};
+            selections.main() = {buffer.clamp(m_anchor), *cursor};
             selections.sort_and_merge_overlapping();
             return true;
         }