Store cursor and eventhandler in buffer instead of view

This is better design because the cursor and eventhandler are things the
buffer should know about directly but the view shouldn't. This should
make it easier to add persistent undo or location saving between
sessions (see #107).

cmd/micro/view.go

@@ -15,7 +15,8 @@ import (
 // It stores information about the cursor, and the viewport
 // that the user sees the buffer from.
 type View struct {
-	Cursor Cursor
+	// A pointer to the buffer's cursor for ease of access
+	Cursor *Cursor
 
 	// The topmost line, used for vertical scrolling
 	Topline int
@@ -33,9 +34,6 @@ type View struct {
 	// How much to offset because of line numbers
 	lineNumOffset int
 
-	// The eventhandler for undo/redo
-	eh *EventHandler
-
 	// Holds the list of gutter messages
 	messages map[string][]GutterMessage
 
@@ -90,8 +88,6 @@ func NewViewWidthHeight(buf *Buffer, w, h int) *View {
 
 	v.OpenBuffer(buf)
 
-	v.eh = NewEventHandler(v)
-
 	v.messages = make(map[string][]GutterMessage)
 
 	v.sline = Statusline{
@@ -162,18 +158,12 @@ func (v *View) CanClose(msg string) bool {
 // This resets the topline, event handler and cursor.
 func (v *View) OpenBuffer(buf *Buffer) {
 	v.Buf = buf
+	v.Cursor = &buf.Cursor
 	v.Topline = 0
 	v.leftCol = 0
-	// Put the cursor at the first spot
-	v.Cursor = Cursor{
-		x: 0,
-		y: 0,
-		v: v,
-	}
 	v.Cursor.ResetSelection()
 	v.messages = make(map[string][]GutterMessage)
 
-	v.eh = NewEventHandler(v)
 	v.matches = Match(v)
 
 	// Set mouseReleased to true because we assume the mouse is not being pressed when
@@ -269,7 +259,7 @@ func (v *View) HandleEvent(event tcell.Event) {
 				v.Cursor.DeleteSelection()
 				v.Cursor.ResetSelection()
 			}
-			v.eh.Insert(v.Cursor.Loc(), string(e.Rune()))
+			v.Buf.Insert(v.Cursor.Loc(), string(e.Rune()))
 			v.Cursor.Right()
 		} else {
 			for key, action := range bindings {
@@ -293,7 +283,7 @@ func (v *View) HandleEvent(event tcell.Event) {
 			v.Cursor.ResetSelection()
 		}
 		clip := e.Text()
-		v.eh.Insert(v.Cursor.Loc(), clip)
+		v.Buf.Insert(v.Cursor.Loc(), clip)
 		v.Cursor.SetLoc(v.Cursor.Loc() + Count(clip))
 		v.freshClip = false
 	case *tcell.EventMouse:
@@ -595,10 +585,20 @@ func (v *View) DisplayView() {
 	}
 }
 
+// DisplayCursor draws the current buffer's cursor to the screen
+func (v *View) DisplayCursor() {
+	// Don't draw the cursor if it is out of the viewport or if it has a selection
+	if (v.Cursor.y-v.Topline < 0 || v.Cursor.y-v.Topline > v.height-1) || v.Cursor.HasSelection() {
+		screen.HideCursor()
+	} else {
+		screen.ShowCursor(v.Cursor.GetVisualX()+v.lineNumOffset-v.leftCol, v.Cursor.y-v.Topline)
+	}
+}
+
 // Display renders the view, the cursor, and statusline
 func (v *View) Display() {
 	v.DisplayView()
-	v.Cursor.Display()
+	v.DisplayCursor()
 	if settings["statusline"].(bool) {
 		v.sline.Display()
 	}