Revert "readline: add multiline support"

This reverts commit 443071db57.

Patch was overly compilicated and made some incorrect assumptions about the
position of the cursor being at the bottom of the screen. @rlidwka and I are
working on getting a proper implementation written.

lib/readline.js

@@ -95,18 +95,13 @@ function Interface(input, output, completer) {
     this.history = [];
     this.historyIndex = -1;
 
-    // a number of lines used by current command
-    this.usedLines = 1;
-
     var winSize = output.getWindowSize();
     exports.columns = winSize[0];
-    exports.rows = winSize[1];
 
     if (process.listeners('SIGWINCH').length === 0) {
       process.on('SIGWINCH', function() {
         var winSize = output.getWindowSize();
         exports.columns = winSize[0];
-        exports.rows = winSize[1];
       });
     }
   }
@@ -118,10 +113,6 @@ Interface.prototype.__defineGetter__('columns', function() {
   return exports.columns;
 });
 
-Interface.prototype.__defineGetter__('rows', function() {
-  return exports.rows;
-});
-
 Interface.prototype.setPrompt = function(prompt, length) {
   this._prompt = prompt;
   if (length) {
@@ -187,53 +178,19 @@ Interface.prototype._addHistory = function() {
 };
 
 
-Interface.prototype._recalcUsedLines = function() {
-  var line = this._prompt + this.line;
-  var newcount = Math.ceil(line.length / this.columns);
-  if (newcount > this.usedLines) this.usedLines = newcount;
-};
-
-
 Interface.prototype._refreshLine = function() {
-  var columns = this.columns;
-  if (!columns) columns = Infinity;
-
-  // See if a number of used lines has changed
-  var oldLines = this.usedLines;
-  this._recalcUsedLines();
-  if (oldLines != this.usedLines) {
-    this.output.cursorTo(0, this.rows - 1);
-    for (var i = oldLines; i < this.usedLines; i++) {
-      this.output.write('\r\n');
-    }
-  }
-
   // Cursor to left edge.
-  if (this.usedLines === 1) {
-    this.output.cursorTo(0);
-  } else {
-    this.output.cursorTo(0, this.rows - this.usedLines);
-  }
+  this.output.cursorTo(0);
 
   // Write the prompt and the current buffer content.
-  var buffer = this._prompt + this.line;
-  this.output.write(buffer);
+  this.output.write(this._prompt);
+  this.output.write(this.line);
 
   // Erase to right.
   this.output.clearLine(1);
-  var clearLinesCnt = this.usedLines - Math.floor(buffer.length / columns) - 1;
-  for (var i = this.rows - clearLinesCnt; i < this.rows; i++) {
-    this.output.cursorTo(0, i);
-    this.output.clearLine(0);
-  }
 
   // Move cursor to original position.
-  var curPos = this._getCursorPos();
-  if (this.usedLines === 1) {
-    this.output.cursorTo(curPos[0]);
-  } else {
-    this.output.cursorTo(curPos[0], this.rows - this.usedLines + curPos[1]);
-  }
+  this.output.cursorTo(this._promptLength + this.cursor);
 };
 
 
@@ -285,7 +242,6 @@ Interface.prototype._insertString = function(c) {
     this.line += c;
     this.cursor += c.length;
     this.output.write(c);
-    this._recalcUsedLines();
   }
 };
 
@@ -459,7 +415,6 @@ Interface.prototype._deleteLineRight = function() {
 Interface.prototype._line = function() {
   var line = this._addHistory();
   this.output.write('\r\n');
-  this.usedLines = 1;
   this._onLine(line);
 };
 
@@ -491,33 +446,6 @@ Interface.prototype._historyPrev = function() {
 };
 
 
-// Returns current cursor's position and line
-Interface.prototype._getCursorPos = function() {
-  var columns = this.columns;
-  var pos = this.cursor + this._promptLength;
-  if (!columns) return [pos, 0];
-
-  var lineNum = Math.floor(pos / columns);
-  var colNum = pos - lineNum * columns;
-  return [colNum, lineNum];
-};
-
-
-Interface.prototype._moveCursor = function(dx) {
-  var oldcursor = this.cursor;
-  var oldLine = this._getCursorPos()[1];
-  this.cursor += dx;
-  var newLine = this._getCursorPos()[1];
-
-  // check if cursors are in the same line
-  if (oldLine == newLine) {
-    this.output.moveCursor(dx, 0);
-  } else {
-    this._refreshLine();
-  }
-};
-
-
 // handle a write from the tty
 Interface.prototype._ttyWrite = function(s, key) {
   var next_word, next_non_word, previous_word, previous_non_word;
@@ -691,13 +619,15 @@ Interface.prototype._ttyWrite = function(s, key) {
 
       case 'left':
         if (this.cursor > 0) {
-          this._moveCursor(-1);
+          this.cursor--;
+          this.output.moveCursor(-1, 0);
         }
         break;
 
       case 'right':
         if (this.cursor != this.line.length) {
-          this._moveCursor(1);
+          this.cursor++;
+          this.output.moveCursor(1, 0);
         }
         break;