Make moveLeft() with huge values span multiple rows

yyrj · Sep 3, 2014 · 29f15d0 · 29f15d0
1 parent 99c07de
commit 29f15d0
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Showing 2 changed files with 20 additions and 5 deletions.
diff --git a/spec/editor-spec.coffee b/spec/editor-spec.coffee
@@ -326,14 +326,24 @@ describe "Editor", ->
         editor.moveLeft(4)
         expect(editor.getCursorScreenPosition()).toEqual [1, 4]
 
+      it "moves the cursor by two rows up when the columnCount is longer than an entire line", ->
+        editor.setCursorScreenPosition([2, 2])
+        editor.moveLeft(34)
+        expect(editor.getCursorScreenPosition()).toEqual [0, 28]
+
+      it "moves the cursor to the beginning columnCount is longer than the position in the buffer", ->
+        editor.setCursorScreenPosition([1, 0])
+        editor.moveLeft(100)
+        expect(editor.getCursorScreenPosition()).toEqual [0, 0]
+
       describe "when the cursor is in the first column", ->
         describe "when there is a previous line", ->
           it "wraps to the end of the previous line", ->
             editor.setCursorScreenPosition(row: 1, column: 0)
             editor.moveLeft()
             expect(editor.getCursorScreenPosition()).toEqual(row: 0, column: buffer.lineForRow(0).length)
 
-          it "moves the cursor by n columns to the left", ->
+          it "moves the cursor by one row up columns to the left", ->
             editor.setCursorScreenPosition([1, 0])
             editor.moveLeft(4)
             expect(editor.getCursorScreenPosition()).toEqual [0, 26]
@@ -344,7 +354,7 @@ describe "Editor", ->
             editor.moveLeft()
             expect(editor.getCursorScreenPosition()).toEqual(row: 0, column: 0)
 
-          it "moves the cursor by n columns to the left", ->
+          it "remains in the same position (0,0) when columnCount is specified", ->
             editor.setCursorScreenPosition([0, 0])
             editor.moveLeft(4)
             expect(editor.getCursorScreenPosition()).toEqual [0, 0]

diff --git a/src/cursor.coffee b/src/cursor.coffee
@@ -274,9 +274,14 @@ class Cursor extends Model
 
       if newColumn >= 0
         column = newColumn
-      else if row > 0
-        row--
-        column = @editor.lineTextForScreenRow(row).length + newColumn + 1
+      else
+        columnDelta = -(newColumn + 1)
+        while columnDelta >= 0 and row > 0
+          row--
+          rowLength = @editor.lineTextForScreenRow(row).length
+          column = rowLength - columnDelta
+          columnDelta -= rowLength
+        column = Math.max(column, 0)
 
       @setScreenPosition({row, column})