From 443071db5749603f816199b9ec8bc512fb441d98 Mon Sep 17 00:00:00 2001
From: Rlidwka <rlidwka@kocharin.ru>
Date: Mon, 5 Mar 2012 19:55:08 +0400
Subject: [PATCH] readline: add multiline support

---
 lib/readline.js | 86 ++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 78 insertions(+), 8 deletions(-)

diff --git a/lib/readline.js b/lib/readline.js
index 2e16229b1efa91..3b6713dae09efc 100644
--- a/lib/readline.js
+++ b/lib/readline.js
@@ -95,13 +95,18 @@ 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];
       });
     }
   }
@@ -113,6 +118,10 @@ 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) {
@@ -178,19 +187,53 @@ 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.
-  this.output.cursorTo(0);
+  if (this.usedLines === 1) {
+    this.output.cursorTo(0);
+  } else {
+    this.output.cursorTo(0, this.rows - this.usedLines);
+  }
 
   // Write the prompt and the current buffer content.
-  this.output.write(this._prompt);
-  this.output.write(this.line);
+  var buffer = this._prompt + this.line;
+  this.output.write(buffer);
 
   // 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.
-  this.output.cursorTo(this._promptLength + this.cursor);
+  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]);
+  }
 };
 
 
@@ -242,6 +285,7 @@ Interface.prototype._insertString = function(c) {
     this.line += c;
     this.cursor += c.length;
     this.output.write(c);
+    this._recalcUsedLines();
   }
 };
 
@@ -415,6 +459,7 @@ Interface.prototype._deleteLineRight = function() {
 Interface.prototype._line = function() {
   var line = this._addHistory();
   this.output.write('\r\n');
+  this.usedLines = 1;
   this._onLine(line);
 };
 
@@ -446,6 +491,33 @@ 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;
@@ -616,15 +688,13 @@ Interface.prototype._ttyWrite = function(s, key) {
 
       case 'left':
         if (this.cursor > 0) {
-          this.cursor--;
-          this.output.moveCursor(-1, 0);
+          this._moveCursor(-1);
         }
         break;
 
       case 'right':
         if (this.cursor != this.line.length) {
-          this.cursor++;
-          this.output.moveCursor(1, 0);
+          this._moveCursor(1);
         }
         break;