introduce ufuzz.js (#1655)

closes #1647

test/ufuzz.js

@@ -0,0 +1,225 @@
+// ufuzz.js
+// derived from https://github.com/qfox/uglyfuzzer by Peter van der Zee
+"use strict";
+
+// workaround for tty output truncation upon process.exit()
+[process.stdout, process.stderr].forEach(function(stream){
+    if (stream._handle && stream._handle.setBlocking)
+        stream._handle.setBlocking(true);
+});
+
+var vm = require("vm");
+var minify = require("..").minify;
+
+function run_code(code) {
+    var stdout = "";
+    var original_write = process.stdout.write;
+    process.stdout.write = function(chunk) {
+        stdout += chunk;
+    };
+    try {
+        new vm.Script(code).runInNewContext({ console: console }, { timeout: 5000 });
+        return stdout;
+    } catch (ex) {
+        return ex;
+    } finally {
+        process.stdout.write = original_write;
+    }
+}
+
+function rng(max) {
+  return Math.floor(max * Math.random());
+}
+
+function createFunctionDecls(n, recurmax) {
+  if (--recurmax < 0) { return ';'; }
+  var s = '';
+  while (--n > 0) {
+    s += createFunctionDecl(recurmax) + '\n';
+  }
+  return s;
+}
+
+var funcs = 0;
+function createFunctionDecl(recurmax) {
+  if (--recurmax < 0) { return ';'; }
+  var func = funcs++;
+  return 'function f' + func + '(){' + createStatements(3, recurmax) + '}\nf' + func + '();';
+}
+
+function createStatements(n, recurmax) {
+  if (--recurmax < 0) { return ';'; }
+  var s = '';
+  while (--n > 0) {
+    s += createStatement(recurmax);
+  }
+  return s;
+}
+
+var loops = 0;
+function createStatement(recurmax) {
+  var loop = ++loops;
+  if (--recurmax < 0) { return ';'; }
+  switch (rng(7)) {
+    case 0:
+      return '{' + createStatement(recurmax) + '}';
+    case 1:
+      return 'if (' + createExpression(recurmax) + ')' + createStatement(recurmax);
+    case 2:
+      return '{var brake' + loop + ' = 5; do {' + createStatement(recurmax) + '} while ((' + createExpression(recurmax) + ') && --brake' + loop + ' > 0);}';
+    case 3:
+      return '{var brake' + loop + ' = 5; while ((' + createExpression(recurmax) + ') && --brake' + loop + ' > 0)' + createStatement(recurmax) + '}';
+    case 4:
+      return 'for (var brake' + loop + ' = 5; (' + createExpression(recurmax) + ') && brake' + loop + ' > 0; --brake' + loop + ')' + createStatement(recurmax);
+    case 5:
+      return ';';
+    case 6:
+      return createExpression() + ';';
+  }
+}
+
+function createExpression(recurmax) {
+  if (--recurmax < 0) { return '0'; }
+  switch (rng(8)) {
+    case 0:
+      return '(' + createUnaryOp() + 'a)';
+    case 1:
+      return '(a' + (Math.random() > 0.5 ? '++' : '--') + ')';
+    case 2:
+      return '(b ' + createAssignment() + ' a)';
+    case 3:
+      return '(' + Math.random() + ' > 0.5 ? a : b)';
+    case 4:
+      return createExpression(recurmax) + createBinaryOp() + createExpression(recurmax);
+    case 5:
+      return createValue();
+    case 6:
+      return '(' + createExpression(recurmax) + ')';
+    case 7:
+      return createExpression(recurmax) + '?(' + createExpression(recurmax) + '):(' + createExpression(recurmax) + ')';
+  }
+}
+
+function createValue() {
+  var values = [
+    'true',
+    'false',
+    '22',
+    '0',
+    '(-1)',
+    'NaN',
+    'undefined',
+    'null',
+    '"foo"',
+    '"bar"' ];
+  return values[rng(values.length)];
+}
+
+function createBinaryOp() {
+  switch (rng(6)) {
+    case 0:
+      return '+';
+    case 1:
+      return '-';
+    case 2:
+      return ',';
+    case 3:
+      return '&&';
+    case 4:
+      return '||';
+    case 5:
+      return '^';
+  }
+}
+
+function createAssignment() {
+  switch (rng(4)) {
+    case 0:
+      return '=';
+    case 1:
+      return '-=';
+    case 2:
+      return '^=';
+    case 3:
+      return '+=';
+  }
+}
+
+function createUnaryOp() {
+  switch (rng(4)) {
+    case 0:
+      return '--';
+    case 1:
+      return '++';
+    case 2:
+      return '~';
+    case 3:
+      return '!';
+  }
+}
+
+function log() {
+    console.log("//=============================================================");
+    console.log("// original code");
+    console.log("//");
+    console.log(original_code);
+    console.log();
+    console.log();
+    console.log("//-------------------------------------------------------------");
+    console.log("// original code (beautify'd)");
+    console.log("//");
+    console.log(beautify_code);
+    console.log();
+    console.log();
+    console.log("//-------------------------------------------------------------");
+    console.log("// uglified code");
+    console.log("//");
+    console.log(uglify_code);
+    console.log();
+    console.log();
+    console.log("original result:");
+    console.log(original_result);
+    console.log("beautified result:");
+    console.log(beautify_result);
+    console.log("uglified result:");
+    console.log(uglify_result);
+}
+
+var num_iterations = +process.argv[2] || 1/0;
+var verbose = !!process.argv[3];
+for (var round = 0; round < num_iterations; round++) {
+    process.stdout.write(round + " of " + num_iterations + "\r");
+    var original_code = [
+        "var a = 100, b = 10;",
+        createFunctionDecls(rng(3) + 1, 10),
+        "console.log(a, b);"
+    ].join("\n");
+    var beautify_code = minify(original_code, {
+        fromString: true,
+        mangle: false,
+        compress: false,
+        output: {
+            beautify: true,
+            bracketize: true,
+        },
+    }).code;
+
+    var uglify_code = minify(beautify_code, {
+        fromString: true,
+        mangle: false,
+        compress: {
+            passes: 3,
+        },
+        output: {
+            beautify: true,
+            bracketize: true,
+        },
+    }).code;
+
+    var original_result = run_code(original_code);
+    var beautify_result = run_code(beautify_code);
+    var uglify_result = run_code(uglify_code);
+    var ok = original_result == beautify_result && original_result == uglify_result;
+    if (verbose || !ok) log();
+    if (!ok) process.exit(1);
+}