Use strings instead of buffers in readline

For eventual large character support.

lib/readline.js

@@ -25,8 +25,7 @@ function Interface (output, isTTY) {
   this.setPrompt("node> ");
 
   // Current line
-  this.buf = new Buffer(kBufSize);
-  this.buf.used = 0;
+  this.line = ""
 
   if (!isTTY) {
     this._tty = false;
@@ -57,7 +56,6 @@ Interface.prototype.setPrompt = function (prompt, length) {
 
 Interface.prototype.prompt  = function () {
   if (this._tty) {
-    this.buf.used = 0;
     this.cursor = 0;
     this._refreshLine();
   } else {
@@ -67,21 +65,18 @@ Interface.prototype.prompt  = function () {
 
 
 Interface.prototype._addHistory = function () {
-  if (this.buf.used === 0) return "";
+  if (this.line.length === 0) return "";
 
-  var b = new Buffer(this.buf.used);
-  this.buf.copy(b, 0, 0, this.buf.used);
-  this.buf.used = 0;
-
-  this.history.unshift(b);
+  this.history.unshift(this.line);
+  this.line = "";
   this.historyIndex = -1;
 
   this.cursor = 0;
 
   // Only store so many
   if (this.history.length > kHistorySize) this.history.pop();
 
-  return b.toString('utf8');
+  return this.history[0];
 };
 
 
@@ -95,9 +90,7 @@ Interface.prototype._refreshLine  = function () {
 
   // Write the prompt and the current buffer content.
   this.output.write(this._prompt);
-  if (this.buf.used > 0) {
-    this.output.write(this.buf.slice(0, this.buf.used));
-  }
+  this.output.write(this.line);
 
   // Erase to right.
   this.output.write('\x1b[0K');
@@ -123,42 +116,31 @@ Interface.prototype.write = function (d) {
 
 
 Interface.prototype._normalWrite = function (b) {
-  for (var i = 0; i < b.length; i++) {
-    var code = b instanceof Buffer ? b[i] : b.charCodeAt(i);
-    if (code === '\n'.charCodeAt(0) || code === '\r'.charCodeAt(0)) {
-      var s = this.buf.toString('utf8', 0, this.buf.used);
-      this.emit('line', s);
-      this.buf.used = 0;
-    } else {
-      this.buf[this.buf.used++] = code;
-    }
-  }
+  // Very simple implementation right now. Should try to break on
+  // new lines.
+  this.emit('line', b.toString());
 };
 
 Interface.prototype._historyNext = function () {
   if (this.historyIndex > 0) {
     this.historyIndex--;
-    this.history[this.historyIndex].copy(this.buf, 0);
-    this.buf.used = this.history[this.historyIndex].length;
-    // set cursor to end of line.
-    this.cursor = this.buf.used;
+    this.line = this.history[this.historyIndex];
+    this.cursor = this.line.length; // set cursor to end of line.
     this._refreshLine();
 
   } else if (this.historyIndex === 0) {
     this.historyIndex = -1;
     this.cursor = 0;
-    this.buf.used = 0;
+    this.line = '';
     this._refreshLine();
   }
 };
 
 Interface.prototype._historyPrev = function () {
   if (this.historyIndex + 1 < this.history.length) {
     this.historyIndex++;
-    this.history[this.historyIndex].copy(this.buf, 0);
-    this.buf.used = this.history[this.historyIndex].length;
-    // set cursor to end of line.
-    this.cursor = this.buf.used;
+    this.line = this.history[this.historyIndex];
+    this.cursor = this.line.length; // set cursor to end of line.
 
     this._refreshLine();
   }
@@ -174,13 +156,12 @@ Interface.prototype._ttyWrite = function (b) {
       break;
 
     case 4: // control-d, delete right or EOF
-      if (this.cursor === 0 && this.buf.used === 0) {
+      if (this.cursor === 0 && this.line.length === 0) {
         this.close();
-      } else if (this.cursor < this.buf.used) {
-        for (var i = this.cursor; i < this.buf.used; i++) {
-          this.buf[i] = this.buf[i+1];
-        }
-        this.buf.used--;
+      } else if (this.cursor < this.line.length) {
+        this.line = this.line.slice(0, this.cursor) 
+                  + this.line.slice(this.cursor+1, this.line.length)
+                  ;
         this._refreshLine();
       }
       break;
@@ -194,23 +175,23 @@ Interface.prototype._ttyWrite = function (b) {
 
     case 127:   /* backspace */
     case 8:     /* ctrl+h */
-      if (this.cursor > 0 && this.buf.used > 0) {
-        for (var i = this.cursor; i < this.buf.used; i++) {
-          this.buf[i-1] = this.buf[i];
-        }
+      if (this.cursor > 0 && this.line.length > 0) {
+        this.line = this.line.slice(0, this.cursor-1)
+                  + this.line.slice(this.cursor, this.line.length)
+                  ;
         this.cursor--;
-        this.buf.used--;
         this._refreshLine();
       }
       break;
 
     case 21: /* Ctrl+u, delete the whole line. */
-      this.cursor = this.buf.used = 0;
+      this.cursor = 0;
+      this.line = '';
       this._refreshLine();
       break;
 
     case 11: /* Ctrl+k, delete from current to end of line. */
-      this.buf.used = this.cursor;
+      this.line = this.line.slice(0, this.cursor);
       this._refreshLine();
       break;
 
@@ -220,7 +201,7 @@ Interface.prototype._ttyWrite = function (b) {
       break;
 
     case 5: /* ctrl+e, go to the end of the line */
-      this.cursor = this.buf.used;
+      this.cursor = this.line.length;
       this._refreshLine();
       break;
 
@@ -232,7 +213,7 @@ Interface.prototype._ttyWrite = function (b) {
       break;
 
     case 6: // control-f, forward one character
-      if (this.cursor != this.buf.used) {
+      if (this.cursor != this.line.length) {
         this.cursor++;
         this._refreshLine();
       }
@@ -249,17 +230,17 @@ Interface.prototype._ttyWrite = function (b) {
     case 27:    /* escape sequence */
       if (b[1] === 98 && this.cursor > 0) { // meta-b - backward word
 
-      } else if (b[1] === 102 && this.cursor < this.buf.used) { // meta-f - forward word
+      } else if (b[1] === 102 && this.cursor < this.line.length) { // meta-f - forward word
 
       } else if (b[1] === 91 && b[2] === 68) { // left arrow
         if (this.cursor > 0) {
           this.cursor--;
-          this._refreshLine();
+          this.output.write('\x1b[0D');
         }
       } else if (b[1] === 91 && b[2] === 67) { // right arrow
-        if (this.cursor != this.buf.used) {
+        if (this.cursor != this.line.length) {
           this.cursor++;
-          this._refreshLine();
+          this.output.write('\x1b[0C');
         }
       } else if (b[1] === 91 && b[2] === 65) { // up arrow
         this._historyPrev();
@@ -269,18 +250,17 @@ Interface.prototype._ttyWrite = function (b) {
       break;
 
     default:
-      if (this.buf.used < kBufSize) {
-        for (var i = this.buf.used + 1; this.cursor < i; i--) {
-          this.buf[i] = this.buf[i-1];
-        }
-        this.buf[this.cursor++] = b[0];
-        this.buf.used++;
-
-        if (this.buf.used == this.cursor) {
-          this.output.write(b);
-        } else {
-          this._refreshLine();
-        }
+      var c = b.toString('utf8');
+      if (this.cursor < this.line.length) {
+        var beg = this.line.slice(0, this.cursor);
+        var end = this.line.slice(this.cursor, this.line.length);
+        this.line = beg + c + end;
+        this.cursor += c.length;
+        this._refreshLine();
+      } else {
+        this.line += c;
+        this.cursor += c.length;
+        this.output.write(c);
       }
       break;
   }