Add savecursor option

This adds the `savecursor` option which will remember where the cursor
was when the file was closed and put it back when the file is opened
again. The option is off by default so that people aren't confused as to
why the cursor isn't at the start of a file when they open it.

This commit also adds a more general ability to serialize a buffer so
various components can be saved (which could also be useful for persistent
undo).

Fixes #107

cmd/micro/view.go

@@ -166,6 +166,7 @@ func (v *View) CanClose(msg string) bool {
 // OpenBuffer opens a new buffer in this view.
 // This resets the topline, event handler and cursor.
 func (v *View) OpenBuffer(buf *Buffer) {
+	v.CloseBuffer()
 	v.Buf = buf
 	v.Cursor = &buf.Cursor
 	v.Topline = 0
@@ -181,6 +182,13 @@ func (v *View) OpenBuffer(buf *Buffer) {
 	v.lastClickTime = time.Time{}
 }
 
+// CloseBuffer performs any closing functions on the buffer
+func (v *View) CloseBuffer() {
+	if v.Buf != nil {
+		v.Buf.Serialize()
+	}
+}
+
 // ReOpen reloads the current buffer
 func (v *View) ReOpen() {
 	if v.CanClose("Continue? (yes, no, save) ") {
@@ -203,7 +211,7 @@ func (v *View) ReOpen() {
 // This is useful if the user has scrolled far away, and then starts typing
 func (v *View) Relocate() bool {
 	ret := false
-	cy := v.Cursor.y
+	cy := v.Cursor.Y
 	scrollmargin := int(settings["scrollmargin"].(float64))
 	if cy < v.Topline+scrollmargin && cy > scrollmargin-1 {
 		v.Topline = cy - scrollmargin
@@ -253,9 +261,9 @@ func (v *View) MoveToMouseClick(x, y int) {
 	if x > Count(v.Buf.Lines[y]) {
 		x = Count(v.Buf.Lines[y])
 	}
-	v.Cursor.x = x
-	v.Cursor.y = y
-	v.Cursor.lastVisualX = v.Cursor.GetVisualX()
+	v.Cursor.X = x
+	v.Cursor.Y = y
+	v.Cursor.LastVisualX = v.Cursor.GetVisualX()
 }
 
 // HandleEvent handles an event passed by the main loop
@@ -345,9 +353,9 @@ func (v *View) HandleEvent(event tcell.Event) {
 					v.lastClickTime = time.Now()
 
 					loc := v.Cursor.Loc()
-					v.Cursor.origSelection[0] = loc
-					v.Cursor.curSelection[0] = loc
-					v.Cursor.curSelection[1] = loc
+					v.Cursor.OrigSelection[0] = loc
+					v.Cursor.CurSelection[0] = loc
+					v.Cursor.CurSelection[1] = loc
 				}
 				v.mouseReleased = false
 			} else if !v.mouseReleased {
@@ -357,7 +365,7 @@ func (v *View) HandleEvent(event tcell.Event) {
 				} else if v.doubleClick {
 					v.Cursor.AddWordToSelection()
 				} else {
-					v.Cursor.curSelection[1] = v.Cursor.Loc()
+					v.Cursor.CurSelection[1] = v.Cursor.Loc()
 				}
 			}
 		case tcell.ButtonNone:
@@ -373,7 +381,7 @@ func (v *View) HandleEvent(event tcell.Event) {
 
 				if !v.doubleClick && !v.tripleClick {
 					v.MoveToMouseClick(x, y)
-					v.Cursor.curSelection[1] = v.Cursor.Loc()
+					v.Cursor.CurSelection[1] = v.Cursor.Loc()
 				}
 				v.mouseReleased = true
 			}
@@ -487,7 +495,7 @@ func (v *View) DisplayView() {
 						x++
 						screen.SetContent(x, lineN, '>', nil, gutterStyle)
 						x++
-						if v.Cursor.y == lineN+v.Topline {
+						if v.Cursor.Y == lineN+v.Topline {
 							messenger.Message(msg.msg)
 							messenger.gutterMessage = true
 						}
@@ -499,7 +507,7 @@ func (v *View) DisplayView() {
 				x++
 				screen.SetContent(x, lineN, ' ', nil, tcell.StyleDefault)
 				x++
-				if v.Cursor.y == lineN+v.Topline && messenger.gutterMessage {
+				if v.Cursor.Y == lineN+v.Topline && messenger.gutterMessage {
 					messenger.Reset()
 					messenger.gutterMessage = false
 				}
@@ -542,8 +550,8 @@ func (v *View) DisplayView() {
 			}
 
 			if v.Cursor.HasSelection() &&
-				(charNum >= v.Cursor.curSelection[0] && charNum < v.Cursor.curSelection[1] ||
-					charNum < v.Cursor.curSelection[0] && charNum >= v.Cursor.curSelection[1]) {
+				(charNum >= v.Cursor.CurSelection[0] && charNum < v.Cursor.CurSelection[1] ||
+					charNum < v.Cursor.CurSelection[0] && charNum >= v.Cursor.CurSelection[1]) {
 
 				lineStyle = tcell.StyleDefault.Reverse(true)
 
@@ -560,8 +568,8 @@ func (v *View) DisplayView() {
 					lineIndentStyle = style
 				}
 				if v.Cursor.HasSelection() &&
-					(charNum >= v.Cursor.curSelection[0] && charNum < v.Cursor.curSelection[1] ||
-						charNum < v.Cursor.curSelection[0] && charNum >= v.Cursor.curSelection[1]) {
+					(charNum >= v.Cursor.CurSelection[0] && charNum < v.Cursor.CurSelection[1] ||
+						charNum < v.Cursor.CurSelection[0] && charNum >= v.Cursor.CurSelection[1]) {
 
 					lineIndentStyle = tcell.StyleDefault.Reverse(true)
 
@@ -591,8 +599,8 @@ func (v *View) DisplayView() {
 		// The newline may be selected, in which case we should draw the selection style
 		// with a space to represent it
 		if v.Cursor.HasSelection() &&
-			(charNum >= v.Cursor.curSelection[0] && charNum < v.Cursor.curSelection[1] ||
-				charNum < v.Cursor.curSelection[0] && charNum >= v.Cursor.curSelection[1]) {
+			(charNum >= v.Cursor.CurSelection[0] && charNum < v.Cursor.CurSelection[1] ||
+				charNum < v.Cursor.CurSelection[0] && charNum >= v.Cursor.CurSelection[1]) {
 
 			selectStyle := defStyle.Reverse(true)
 
@@ -609,10 +617,10 @@ 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() {
+	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)
+		screen.ShowCursor(v.Cursor.GetVisualX()+v.lineNumOffset-v.leftCol, v.Cursor.Y-v.Topline)
 	}
 }