make code generator deopt on input >100KB

lib/babel/generation/buffer.js

@@ -5,14 +5,21 @@ module.exports = Buffer;
 var repeating = require("repeating");
 var trimRight = require("trim-right");
 var isBoolean = require("lodash/lang/isBoolean");
+var messages  = require("../messages");
 var includes  = require("lodash/collection/includes");
 var isNumber  = require("lodash/lang/isNumber");
 
-function Buffer(position, format) {
+function Buffer(position, format, opts, code) {
   this.position = position;
   this._indent  = format.indent.base;
   this.format   = format;
+  this.deopt    = false;
   this.buf      = "";
+
+  if (code.length > 100000) { // 100KB
+    this.deopt = true;
+    console.error(messages.get("codeGeneratorDeopt", opts.filename, "100KB"));
+  }
 }
 
 Buffer.prototype.get = function () {
@@ -20,7 +27,7 @@ Buffer.prototype.get = function () {
 };
 
 Buffer.prototype.getIndent = function () {
-  if (this.format.compact || this.format.concise) {
+  if (this.deopt || this.format.concise) {
     return "";
   } else {
     return repeating(this.format.indent.style, this._indent);
@@ -58,14 +65,14 @@ Buffer.prototype.keyword = function (name) {
 };
 
 Buffer.prototype.space = function () {
-  if (this.format.compact) return;
-
-  if (this.buf && !this.isLast([" ", "\n"])) {
+  if (this.deopt) return;
+  if (this.buf && !this.isLast(" ") && !this.isLast("\n")) {
     this.push(" ");
   }
 };
 
 Buffer.prototype.removeLast = function (cha) {
+  if (this.deopt) return;
   if (!this.isLast(cha)) return;
 
   this.buf = this.buf.substr(0, this.buf.length - 1);
@@ -73,7 +80,9 @@ Buffer.prototype.removeLast = function (cha) {
 };
 
 Buffer.prototype.newline = function (i, removeLast) {
-  if (this.format.compact || this.format.concise) {
+  if (this.deopt) return;
+
+  if (this.format.concise) {
     this.space();
     return;
   }
@@ -81,11 +90,11 @@ Buffer.prototype.newline = function (i, removeLast) {
   removeLast = removeLast || false;
 
   if (isNumber(i)) {
-    if (this.endsWith("{\n")) i--;
-    if (this.endsWith(repeating("\n", i > 0 ? i : 0))) return;
+    if (this.isLast("\n")) i--;
 
-    while (i--) {
+    while (i > 0) {
       this._newline(removeLast);
+      i--;
     }
     return;
   }
@@ -101,36 +110,11 @@ Buffer.prototype._newline = function (removeLast) {
   if (removeLast && this.isLast("\n")) this.removeLast("\n");
 
   this.removeLast(" ");
-
-  // remove whitespace if last character was a newline
-  this._removeSpacesAfterLastNewline();
   this._push("\n");
 };
 
-/**
- * If buffer ends with a newline and some spaces after it, trim those spaces.
- */
-Buffer.prototype._removeSpacesAfterLastNewline = function () {
-  var lastNewlineIndex = this.buf.lastIndexOf("\n");
-  if (lastNewlineIndex === -1)
-    return;
-
-  var index = this.buf.length - 1;
-  while (index > lastNewlineIndex) {
-    if (this.buf[index] !== " ") {
-      break;
-    }
-
-    index--;
-  }
-
-  if (index === lastNewlineIndex) {
-    this.buf = this.buf.substring(0, index + 1);
-  }
-};
-
 Buffer.prototype.push = function (str, noIndent) {
-  if (this._indent && !noIndent && str !== "\n") {
+  if (!this.deopt && this._indent && !noIndent && str !== "\n") {
     // we have an indent level and we aren't pushing a newline
     var indent = this.getIndent();
 
@@ -138,7 +122,7 @@ Buffer.prototype.push = function (str, noIndent) {
     str = str.replace(/\n/g, "\n" + indent);
 
     // we've got a newline before us so prepend on the indentation
-    if (this.isLast("\n")) str = indent + str;
+    if (this.isLast("\n")) this._push(indent);
   }
 
   this._push(str);
@@ -149,14 +133,10 @@ Buffer.prototype._push = function (str) {
   this.buf += str;
 };
 
-Buffer.prototype.endsWith = function (str) {
-  var d = this.buf.length - str.length;
-  return d >= 0 && this.buf.lastIndexOf(str) === d;
-};
+Buffer.prototype.isLast = function (cha) {
+  if (this.deopt) return false;
 
-Buffer.prototype.isLast = function (cha, shouldTrimRight) {
   var buf = this.buf;
-  if (shouldTrimRight) buf = trimRight(buf);
   var last = buf[buf.length - 1];
 
   if (Array.isArray(cha)) {

lib/babel/generation/generators/statements.js

@@ -22,12 +22,7 @@ exports.IfStatement = function (node, print) {
 
   if (node.alternate) {
     if (this.isLast("}")) this.space();
-    this.keyword("else");
-
-    if (this.format.format && !t.isBlockStatement(node.alternate)) {
-      this.push(" ");
-    }
-
+    this.push("else ");
     print.indentOnComments(node.alternate);
   }
 };
@@ -189,7 +184,7 @@ exports.VariableDeclaration = function (node, print, parent) {
   }
 
   var sep = ",";
-  if (hasInits) {
+  if (!this.buffer.deopt && hasInits) {
     sep += "\n" + repeating(" ", node.kind.length + 1);
   } else {
     sep += " ";

lib/babel/generation/generators/types.js

@@ -72,7 +72,7 @@ exports.ArrayPattern = function (node, print) {
       // both (all) of the holes.
       self.push(",");
     } else {
-      if (i > 0 && !self.format.compact) self.push(" ");
+      if (i > 0) self.push(" ");
       print(elem);
       if (i < len - 1) self.push(",");
     }

lib/babel/generation/index.js

@@ -28,10 +28,10 @@ function CodeGenerator(ast, opts, code) {
   this.opts     = opts;
   this.ast      = ast;
 
-  this.whitespace = new Whitespace(this.tokens, this.comments);
+  this.whitespace = new Whitespace(this.tokens, this.comments, this.format);
   this.position   = new Position;
   this.map        = new SourceMap(this.position, opts, code);
-  this.buffer     = new Buffer(this.position, this.format);
+  this.buffer     = new Buffer(this.position, this.format, opts, code);
 }
 
 each(Buffer.prototype, function (fn, key) {
@@ -50,7 +50,6 @@ CodeGenerator.normalizeOptions = function (code, opts) {
   return merge({
     parentheses: true,
     comments: opts.comments == null || opts.comments,
-    compact: false,
     concise: false,
     indent: {
       adjustMultilineComment: true,
@@ -115,11 +114,7 @@ CodeGenerator.prototype.buildPrint = function (parent) {
 
   print.list = function (items, opts) {
     opts = opts || {};
-
-    var sep = opts.separator || ", ";
-    if (self.format.compact) sep = ",";
-    opts.separator = sep;
-
+    opts.separator = opts.separator || ", ";
     print.join(items, opts);
   };
 
@@ -301,7 +296,8 @@ CodeGenerator.prototype._getComments = function (key, node) {
 };
 
 CodeGenerator.prototype._printComments = function (comments) {
-  if (this.format.compact) return;
+  if (this.buffer.deopt) return;
+
   if (!this.format.comments) return;
   if (!comments || !comments.length) return;
 

lib/babel/generation/whitespace.js

@@ -13,11 +13,13 @@ var sortBy = require("lodash/collection/sortBy");
  * @param {Number} max Array length
  * @returns {Number} shiftedIndex
  */
+
 function getLookupIndex(i, base, max) {
   i += base;
 
-  if (i >= max)
+  if (i >= max) {
     i -= max;
+  }
 
   return i;
 }

lib/babel/messages.js

@@ -17,7 +17,8 @@ exports.messages = {
   modulesIllegalExportName: "Illegal export $1",
   unknownForHead: "Unknown node type $1 in ForStatement",
   didYouMean: "Did you mean $1?",
-  evalInStrictMode: "eval is not allowed in strict mode"
+  evalInStrictMode: "eval is not allowed in strict mode",
+  codeGeneratorDeopt: "Note: The code generator has deoptimised the styling of $1 as it exceeds the max of $2."
 };
 
 exports.get = function (key) {