vnfmarket/src/main/webapp/vnfmarket/node_modules/istanbul/lib/instrumenter.js

   1 /*
   2  Copyright (c) 2012, Yahoo! Inc.  All rights reserved.
   3  Copyrights licensed under the New BSD License. See the accompanying LICENSE file for terms.
   4  */
   5
   6 /*global esprima, escodegen, window */
   7 (function (isNode) {
   8     "use strict";
   9     var SYNTAX,
  10         nodeType,
  11         ESP = isNode ? require('esprima') : esprima,
  12         ESPGEN = isNode ? require('escodegen') : escodegen,  //TODO - package as dependency
  13         crypto = isNode ? require('crypto') : null,
  14         LEADER_WRAP = '(function () { ',
  15         TRAILER_WRAP = '\n}());',
  16         COMMENT_RE = /^\s*istanbul\s+ignore\s+(if|else|next)(?=\W|$)/,
  17         astgen,
  18         preconditions,
  19         cond,
  20         isArray = Array.isArray;
  21
  22     /* istanbul ignore if: untestable */
  23     if (!isArray) {
  24         isArray = function (thing) { return thing &&  Object.prototype.toString.call(thing) === '[object Array]'; };
  25     }
  26
  27     if (!isNode) {
  28         preconditions = {
  29             'Could not find esprima': ESP,
  30             'Could not find escodegen': ESPGEN,
  31             'JSON object not in scope': JSON,
  32             'Array does not implement push': [].push,
  33             'Array does not implement unshift': [].unshift
  34         };
  35         /* istanbul ignore next: untestable */
  36         for (cond in preconditions) {
  37             if (preconditions.hasOwnProperty(cond)) {
  38                 if (!preconditions[cond]) { throw new Error(cond); }
  39             }
  40         }
  41     }
  42
  43     function generateTrackerVar(filename, omitSuffix) {
  44         var hash, suffix;
  45         if (crypto !== null) {
  46             hash = crypto.createHash('md5');
  47             hash.update(filename);
  48             suffix = hash.digest('base64');
  49             //trim trailing equal signs, turn identifier unsafe chars to safe ones + => _ and / => $
  50             suffix = suffix.replace(new RegExp('=', 'g'), '')
  51                 .replace(new RegExp('\\+', 'g'), '_')
  52                 .replace(new RegExp('/', 'g'), '$');
  53         } else {
  54             window.__cov_seq = window.__cov_seq || 0;
  55             window.__cov_seq += 1;
  56             suffix = window.__cov_seq;
  57         }
  58         return '__cov_' + (omitSuffix ? '' : suffix);
  59     }
  60
  61     function pushAll(ary, thing) {
  62         if (!isArray(thing)) {
  63             thing = [ thing ];
  64         }
  65         Array.prototype.push.apply(ary, thing);
  66     }
  67
  68     SYNTAX = {
  69         // keep in sync with estraverse's VisitorKeys
  70         AssignmentExpression: ['left', 'right'],
  71         AssignmentPattern: ['left', 'right'],
  72         ArrayExpression: ['elements'],
  73         ArrayPattern: ['elements'],
  74         ArrowFunctionExpression: ['params', 'body'],
  75         AwaitExpression: ['argument'], // CAUTION: It's deferred to ES7.
  76         BlockStatement: ['body'],
  77         BinaryExpression: ['left', 'right'],
  78         BreakStatement: ['label'],
  79         CallExpression: ['callee', 'arguments'],
  80         CatchClause: ['param', 'body'],
  81         ClassBody: ['body'],
  82         ClassDeclaration: ['id', 'superClass', 'body'],
  83         ClassExpression: ['id', 'superClass', 'body'],
  84         ComprehensionBlock: ['left', 'right'],  // CAUTION: It's deferred to ES7.
  85         ComprehensionExpression: ['blocks', 'filter', 'body'],  // CAUTION: It's deferred to ES7.
  86         ConditionalExpression: ['test', 'consequent', 'alternate'],
  87         ContinueStatement: ['label'],
  88         DebuggerStatement: [],
  89         DirectiveStatement: [],
  90         DoWhileStatement: ['body', 'test'],
  91         EmptyStatement: [],
  92         ExportAllDeclaration: ['source'],
  93         ExportDefaultDeclaration: ['declaration'],
  94         ExportNamedDeclaration: ['declaration', 'specifiers', 'source'],
  95         ExportSpecifier: ['exported', 'local'],
  96         ExpressionStatement: ['expression'],
  97         ForStatement: ['init', 'test', 'update', 'body'],
  98         ForInStatement: ['left', 'right', 'body'],
  99         ForOfStatement: ['left', 'right', 'body'],
 100         FunctionDeclaration: ['id', 'params', 'body'],
 101         FunctionExpression: ['id', 'params', 'body'],
 102         GeneratorExpression: ['blocks', 'filter', 'body'],  // CAUTION: It's deferred to ES7.
 103         Identifier: [],
 104         IfStatement: ['test', 'consequent', 'alternate'],
 105         ImportDeclaration: ['specifiers', 'source'],
 106         ImportDefaultSpecifier: ['local'],
 107         ImportNamespaceSpecifier: ['local'],
 108         ImportSpecifier: ['imported', 'local'],
 109         Literal: [],
 110         LabeledStatement: ['label', 'body'],
 111         LogicalExpression: ['left', 'right'],
 112         MemberExpression: ['object', 'property'],
 113         MethodDefinition: ['key', 'value'],
 114         ModuleSpecifier: [],
 115         NewExpression: ['callee', 'arguments'],
 116         ObjectExpression: ['properties'],
 117         ObjectPattern: ['properties'],
 118         Program: ['body'],
 119         Property: ['key', 'value'],
 120         RestElement: [ 'argument' ],
 121         ReturnStatement: ['argument'],
 122         SequenceExpression: ['expressions'],
 123         SpreadElement: ['argument'],
 124         Super: [],
 125         SwitchStatement: ['discriminant', 'cases'],
 126         SwitchCase: ['test', 'consequent'],
 127         TaggedTemplateExpression: ['tag', 'quasi'],
 128         TemplateElement: [],
 129         TemplateLiteral: ['quasis', 'expressions'],
 130         ThisExpression: [],
 131         ThrowStatement: ['argument'],
 132         TryStatement: ['block', 'handler', 'finalizer'],
 133         UnaryExpression: ['argument'],
 134         UpdateExpression: ['argument'],
 135         VariableDeclaration: ['declarations'],
 136         VariableDeclarator: ['id', 'init'],
 137         WhileStatement: ['test', 'body'],
 138         WithStatement: ['object', 'body'],
 139         YieldExpression: ['argument']
 140     };
 141
 142     for (nodeType in SYNTAX) {
 143         /* istanbul ignore else: has own property */
 144         if (SYNTAX.hasOwnProperty(nodeType)) {
 145             SYNTAX[nodeType] = { name: nodeType, children: SYNTAX[nodeType] };
 146         }
 147     }
 148
 149     astgen = {
 150         variable: function (name) { return { type: SYNTAX.Identifier.name, name: name }; },
 151         stringLiteral: function (str) { return { type: SYNTAX.Literal.name, value: String(str) }; },
 152         numericLiteral: function (num) { return { type: SYNTAX.Literal.name, value: Number(num) }; },
 153         statement: function (contents) { return { type: SYNTAX.ExpressionStatement.name, expression: contents }; },
 154         dot: function (obj, field) { return { type: SYNTAX.MemberExpression.name, computed: false, object: obj, property: field }; },
 155         subscript: function (obj, sub) { return { type: SYNTAX.MemberExpression.name, computed: true, object: obj, property: sub }; },
 156         postIncrement: function (obj) { return { type: SYNTAX.UpdateExpression.name, operator: '++', prefix: false, argument: obj }; },
 157         sequence: function (one, two) { return { type: SYNTAX.SequenceExpression.name, expressions: [one, two] }; },
 158         returnStatement: function (expr) { return { type: SYNTAX.ReturnStatement.name, argument: expr }; }
 159     };
 160
 161     function Walker(walkMap, preprocessor, scope, debug) {
 162         this.walkMap = walkMap;
 163         this.preprocessor = preprocessor;
 164         this.scope = scope;
 165         this.debug = debug;
 166         if (this.debug) {
 167             this.level = 0;
 168             this.seq = true;
 169         }
 170     }
 171
 172     function defaultWalker(node, walker) {
 173
 174         var type = node.type,
 175             preprocessor,
 176             postprocessor,
 177             children = SYNTAX[type],
 178             // don't run generated nodes thru custom walks otherwise we will attempt to instrument the instrumentation code :)
 179             applyCustomWalker = !!node.loc || node.type === SYNTAX.Program.name,
 180             walkerFn = applyCustomWalker ? walker.walkMap[type] : null,
 181             i,
 182             j,
 183             walkFnIndex,
 184             childType,
 185             childNode,
 186             ret,
 187             childArray,
 188             childElement,
 189             pathElement,
 190             assignNode,
 191             isLast;
 192
 193         if (!SYNTAX[type]) {
 194             console.error(node);
 195             console.error('Unsupported node type:' + type);
 196             return;
 197         }
 198         children = SYNTAX[type].children;
 199         /* istanbul ignore if: guard */
 200         if (node.walking) { throw new Error('Infinite regress: Custom walkers may NOT call walker.apply(node)'); }
 201         node.walking = true;
 202
 203         ret = walker.apply(node, walker.preprocessor);
 204
 205         preprocessor = ret.preprocessor;
 206         if (preprocessor) {
 207             delete ret.preprocessor;
 208             ret = walker.apply(node, preprocessor);
 209         }
 210
 211         if (isArray(walkerFn)) {
 212             for (walkFnIndex = 0; walkFnIndex < walkerFn.length; walkFnIndex += 1) {
 213                 isLast = walkFnIndex === walkerFn.length - 1;
 214                 ret = walker.apply(ret, walkerFn[walkFnIndex]);
 215                 /*istanbul ignore next: paranoid check */
 216                 if (ret.type !== type && !isLast) {
 217                     throw new Error('Only the last walker is allowed to change the node type: [type was: ' + type + ' ]');
 218                 }
 219             }
 220         } else {
 221             if (walkerFn) {
 222                 ret = walker.apply(node, walkerFn);
 223             }
 224         }
 225
 226         for (i = 0; i < children.length; i += 1) {
 227             childType = children[i];
 228             childNode = node[childType];
 229             if (childNode && !childNode.skipWalk) {
 230                 pathElement = { node: node, property: childType };
 231                 if (isArray(childNode)) {
 232                     childArray = [];
 233                     for (j = 0; j < childNode.length; j += 1) {
 234                         childElement = childNode[j];
 235                         pathElement.index = j;
 236                         if (childElement) {
 237                           assignNode = walker.apply(childElement, null, pathElement);
 238                           if (isArray(assignNode.prepend)) {
 239                               pushAll(childArray, assignNode.prepend);
 240                               delete assignNode.prepend;
 241                           }
 242                         } else {
 243                             assignNode = undefined;
 244                         }
 245                         pushAll(childArray, assignNode);
 246                     }
 247                     node[childType] = childArray;
 248                 } else {
 249                     assignNode = walker.apply(childNode, null, pathElement);
 250                     /*istanbul ignore if: paranoid check */
 251                     if (isArray(assignNode.prepend)) {
 252                         throw new Error('Internal error: attempt to prepend statements in disallowed (non-array) context');
 253                         /* if this should be allowed, this is how to solve it
 254                         tmpNode = { type: 'BlockStatement', body: [] };
 255                         pushAll(tmpNode.body, assignNode.prepend);
 256                         pushAll(tmpNode.body, assignNode);
 257                         node[childType] = tmpNode;
 258                         delete assignNode.prepend;
 259                         */
 260                     } else {
 261                         node[childType] = assignNode;
 262                     }
 263                 }
 264             }
 265         }
 266
 267         postprocessor = ret.postprocessor;
 268         if (postprocessor) {
 269             delete ret.postprocessor;
 270             ret = walker.apply(ret, postprocessor);
 271         }
 272
 273         delete node.walking;
 274
 275         return ret;
 276     }
 277
 278     Walker.prototype = {
 279         startWalk: function (node) {
 280             this.path = [];
 281             this.apply(node);
 282         },
 283
 284         apply: function (node, walkFn, pathElement) {
 285             var ret, i, seq, prefix;
 286
 287             walkFn = walkFn || defaultWalker;
 288             if (this.debug) {
 289                 this.seq += 1;
 290                 this.level += 1;
 291                 seq = this.seq;
 292                 prefix = '';
 293                 for (i = 0; i < this.level; i += 1) { prefix += '    '; }
 294                 console.log(prefix + 'Enter (' + seq + '):' + node.type);
 295             }
 296             if (pathElement) { this.path.push(pathElement); }
 297             ret = walkFn.call(this.scope, node, this);
 298             if (pathElement) { this.path.pop(); }
 299             if (this.debug) {
 300                 this.level -= 1;
 301                 console.log(prefix + 'Return (' + seq + '):' + node.type);
 302             }
 303             return ret || node;
 304         },
 305
 306         startLineForNode: function (node) {
 307             return node && node.loc && node.loc.start ? node.loc.start.line : /* istanbul ignore next: guard */ null;
 308         },
 309
 310         ancestor: function (n) {
 311             return this.path.length > n - 1 ? this.path[this.path.length - n] : /* istanbul ignore next: guard */ null;
 312         },
 313
 314         parent: function () {
 315             return this.ancestor(1);
 316         },
 317
 318         isLabeled: function () {
 319             var el = this.parent();
 320             return el && el.node.type === SYNTAX.LabeledStatement.name;
 321         }
 322     };
 323
 324     /**
 325      * mechanism to instrument code for coverage. It uses the `esprima` and
 326      * `escodegen` libraries for JS parsing and code generation respectively.
 327      *
 328      * Works on `node` as well as the browser.
 329      *
 330      * Usage on nodejs
 331      * ---------------
 332      *
 333      *      var instrumenter = new require('istanbul').Instrumenter(),
 334      *          changed = instrumenter.instrumentSync('function meaningOfLife() { return 42; }', 'filename.js');
 335      *
 336      * Usage in a browser
 337      * ------------------
 338      *
 339      * Load `esprima.js`, `escodegen.js` and `instrumenter.js` (this file) using `script` tags or other means.
 340      *
 341      * Create an instrumenter object as:
 342      *
 343      *      var instrumenter = new Instrumenter(),
 344      *          changed = instrumenter.instrumentSync('function meaningOfLife() { return 42; }', 'filename.js');
 345      *
 346      * Aside from demonstration purposes, it is unclear why you would want to instrument code in a browser.
 347      *
 348      * @class Instrumenter
 349      * @constructor
 350      * @param {Object} options Optional. Configuration options.
 351      * @param {String} [options.coverageVariable] the global variable name to use for
 352      *      tracking coverage. Defaults to `__coverage__`
 353      * @param {Boolean} [options.embedSource] whether to embed the source code of every
 354      *      file as an array in the file coverage object for that file. Defaults to `false`
 355      * @param {Boolean} [options.preserveComments] whether comments should be preserved in the output. Defaults to `false`
 356      * @param {Boolean} [options.noCompact] emit readable code when set. Defaults to `false`
 357      * @param {Boolean} [options.noAutoWrap] do not automatically wrap the source in
 358      *      an anonymous function before covering it. By default, code is wrapped in
 359      *      an anonymous function before it is parsed. This is done because
 360      *      some nodejs libraries have `return` statements outside of
 361      *      a function which is technically invalid Javascript and causes the parser to fail.
 362      *      This construct, however, works correctly in node since module loading
 363      *      is done in the context of an anonymous function.
 364      *
 365      * Note that the semantics of the code *returned* by the instrumenter does not change in any way.
 366      * The function wrapper is "unwrapped" before the instrumented code is generated.
 367      * @param {Object} [options.codeGenerationOptions] an object that is directly passed to the `escodegen`
 368      *      library as configuration for code generation. The `noCompact` setting is not honored when this
 369      *      option is specified
 370      * @param {Boolean} [options.debug] assist in debugging. Currently, the only effect of
 371      *      setting this option is a pretty-print of the coverage variable. Defaults to `false`
 372      * @param {Boolean} [options.walkDebug] assist in debugging of the AST walker used by this class.
 373      *
 374      */
 375     function Instrumenter(options) {
 376         this.opts = options || {
 377             debug: false,
 378             walkDebug: false,
 379             coverageVariable: '__coverage__',
 380             codeGenerationOptions: undefined,
 381             noAutoWrap: false,
 382             noCompact: false,
 383             embedSource: false,
 384             preserveComments: false
 385         };
 386
 387         this.walker = new Walker({
 388             ArrowFunctionExpression: [ this.arrowBlockConverter ],
 389             ExpressionStatement: this.coverStatement,
 390             BreakStatement: this.coverStatement,
 391             ContinueStatement: this.coverStatement,
 392             DebuggerStatement: this.coverStatement,
 393             ReturnStatement: this.coverStatement,
 394             ThrowStatement: this.coverStatement,
 395             TryStatement: [ this.paranoidHandlerCheck, this.coverStatement],
 396             VariableDeclaration: this.coverStatement,
 397             IfStatement: [ this.ifBlockConverter, this.coverStatement, this.ifBranchInjector ],
 398             ForStatement: [ this.skipInit, this.loopBlockConverter, this.coverStatement ],
 399             ForInStatement: [ this.skipLeft, this.loopBlockConverter, this.coverStatement ],
 400             ForOfStatement: [ this.skipLeft, this.loopBlockConverter, this.coverStatement ],
 401             WhileStatement: [ this.loopBlockConverter, this.coverStatement ],
 402             DoWhileStatement: [ this.loopBlockConverter, this.coverStatement ],
 403             SwitchStatement: [ this.coverStatement, this.switchBranchInjector ],
 404             SwitchCase: [ this.switchCaseInjector ],
 405             WithStatement: [ this.withBlockConverter, this.coverStatement ],
 406             FunctionDeclaration: [ this.coverFunction, this.coverStatement ],
 407             FunctionExpression: this.coverFunction,
 408             LabeledStatement: this.coverStatement,
 409             ConditionalExpression: this.conditionalBranchInjector,
 410             LogicalExpression: this.logicalExpressionBranchInjector,
 411             ObjectExpression: this.maybeAddType
 412         }, this.extractCurrentHint, this, this.opts.walkDebug);
 413
 414         //unit testing purposes only
 415         if (this.opts.backdoor && this.opts.backdoor.omitTrackerSuffix) {
 416             this.omitTrackerSuffix = true;
 417         }
 418     }
 419
 420     Instrumenter.prototype = {
 421         /**
 422          * synchronous instrumentation method. Throws when illegal code is passed to it
 423          * @method instrumentSync
 424          * @param {String} code the code to be instrumented as a String
 425          * @param {String} filename Optional. The name of the file from which
 426          *  the code was read. A temporary filename is generated when not specified.
 427          *  Not specifying a filename is only useful for unit tests and demonstrations
 428          *  of this library.
 429          */
 430         instrumentSync: function (code, filename) {
 431             var program;
 432
 433             //protect from users accidentally passing in a Buffer object instead
 434             if (typeof code !== 'string') { throw new Error('Code must be string'); }
 435             if (code.charAt(0) === '#') { //shebang, 'comment' it out, won't affect syntax tree locations for things we care about
 436                 code = '//' + code;
 437             }
 438             if (!this.opts.noAutoWrap) {
 439                 code = LEADER_WRAP + code + TRAILER_WRAP;
 440             }
 441             program = ESP.parse(code, {
 442                 loc: true,
 443                 range: true,
 444                 tokens: this.opts.preserveComments,
 445                 comment: true
 446             });
 447             if (this.opts.preserveComments) {
 448                 program = ESPGEN.attachComments(program, program.comments, program.tokens);
 449             }
 450             if (!this.opts.noAutoWrap) {
 451                 program = {
 452                     type: SYNTAX.Program.name,
 453                     body: program.body[0].expression.callee.body.body,
 454                     comments: program.comments
 455                 };
 456             }
 457             return this.instrumentASTSync(program, filename, code);
 458         },
 459         filterHints: function (comments) {
 460             var ret = [],
 461                 i,
 462                 comment,
 463                 groups;
 464             if (!(comments && isArray(comments))) {
 465                 return ret;
 466             }
 467             for (i = 0; i < comments.length; i += 1) {
 468                 comment = comments[i];
 469                 /* istanbul ignore else: paranoid check */
 470                 if (comment && comment.value && comment.range && isArray(comment.range)) {
 471                     groups = String(comment.value).match(COMMENT_RE);
 472                     if (groups) {
 473                         ret.push({ type: groups[1], start: comment.range[0], end: comment.range[1] });
 474                     }
 475                 }
 476             }
 477             return ret;
 478         },
 479         extractCurrentHint: function (node) {
 480             if (!node.range) { return; }
 481             var i = this.currentState.lastHintPosition + 1,
 482                 hints = this.currentState.hints,
 483                 nodeStart = node.range[0],
 484                 hint;
 485             this.currentState.currentHint = null;
 486             while (i < hints.length) {
 487                 hint = hints[i];
 488                 if (hint.end < nodeStart) {
 489                     this.currentState.currentHint = hint;
 490                     this.currentState.lastHintPosition = i;
 491                     i += 1;
 492                 } else {
 493                     break;
 494                 }
 495             }
 496         },
 497         /**
 498          * synchronous instrumentation method that instruments an AST instead.
 499          * @method instrumentASTSync
 500          * @param {String} program the AST to be instrumented
 501          * @param {String} filename Optional. The name of the file from which
 502          *  the code was read. A temporary filename is generated when not specified.
 503          *  Not specifying a filename is only useful for unit tests and demonstrations
 504          *  of this library.
 505          *  @param {String} originalCode the original code corresponding to the AST,
 506          *  used for embedding the source into the coverage object
 507          */
 508         instrumentASTSync: function (program, filename, originalCode) {
 509             var usingStrict = false,
 510                 codegenOptions,
 511                 generated,
 512                 preamble,
 513                 lineCount,
 514                 i;
 515             filename = filename || String(new Date().getTime()) + '.js';
 516             this.sourceMap = null;
 517             this.coverState = {
 518                 path: filename,
 519                 s: {},
 520                 b: {},
 521                 f: {},
 522                 fnMap: {},
 523                 statementMap: {},
 524                 branchMap: {}
 525             };
 526             this.currentState = {
 527                 trackerVar: generateTrackerVar(filename, this.omitTrackerSuffix),
 528                 func: 0,
 529                 branch: 0,
 530                 variable: 0,
 531                 statement: 0,
 532                 hints: this.filterHints(program.comments),
 533                 currentHint: null,
 534                 lastHintPosition: -1,
 535                 ignoring: 0
 536             };
 537             if (program.body && program.body.length > 0 && this.isUseStrictExpression(program.body[0])) {
 538                 //nuke it
 539                 program.body.shift();
 540                 //and add it back at code generation time
 541                 usingStrict = true;
 542             }
 543             this.walker.startWalk(program);
 544             codegenOptions = this.opts.codeGenerationOptions || { format: { compact: !this.opts.noCompact }};
 545             codegenOptions.comment = this.opts.preserveComments;
 546             //console.log(JSON.stringify(program, undefined, 2));
 547
 548             generated = ESPGEN.generate(program, codegenOptions);
 549             preamble = this.getPreamble(originalCode || '', usingStrict);
 550
 551             if (generated.map && generated.code) {
 552                 lineCount = preamble.split(/\r\n|\r|\n/).length;
 553                 // offset all the generated line numbers by the number of lines in the preamble
 554                 for (i = 0; i < generated.map._mappings._array.length; i += 1) {
 555                     generated.map._mappings._array[i].generatedLine += lineCount;
 556                 }
 557                 this.sourceMap = generated.map;
 558                 generated = generated.code;
 559             }
 560
 561             return preamble + '\n' + generated + '\n';
 562         },
 563         /**
 564          * Callback based instrumentation. Note that this still executes synchronously in the same process tick
 565          * and calls back immediately. It only provides the options for callback style error handling as
 566          * opposed to a `try-catch` style and nothing more. Implemented as a wrapper over `instrumentSync`
 567          *
 568          * @method instrument
 569          * @param {String} code the code to be instrumented as a String
 570          * @param {String} filename Optional. The name of the file from which
 571          *  the code was read. A temporary filename is generated when not specified.
 572          *  Not specifying a filename is only useful for unit tests and demonstrations
 573          *  of this library.
 574          * @param {Function(err, instrumentedCode)} callback - the callback function
 575          */
 576         instrument: function (code, filename, callback) {
 577
 578             if (!callback && typeof filename === 'function') {
 579                 callback = filename;
 580                 filename = null;
 581             }
 582             try {
 583                 callback(null, this.instrumentSync(code, filename));
 584             } catch (ex) {
 585                 callback(ex);
 586             }
 587         },
 588         /**
 589          * returns the file coverage object for the code that was instrumented
 590          * just before calling this method. Note that this represents a
 591          * "zero-coverage" object which is not even representative of the code
 592          * being loaded in node or a browser (which would increase the statement
 593          * counts for mainline code).
 594          * @method lastFileCoverage
 595          * @return {Object} a "zero-coverage" file coverage object for the code last instrumented
 596          * by this instrumenter
 597          */
 598         lastFileCoverage: function () {
 599             return this.coverState;
 600         },
 601         /**
 602          * returns the source map object for the code that was instrumented
 603          * just before calling this method.
 604          * @method lastSourceMap
 605          * @return {Object} a source map object for the code last instrumented
 606          * by this instrumenter
 607          */
 608         lastSourceMap: function () {
 609             return this.sourceMap;
 610         },
 611         fixColumnPositions: function (coverState) {
 612             var offset = LEADER_WRAP.length,
 613                 fixer = function (loc) {
 614                     if (loc.start.line === 1) {
 615                         loc.start.column -= offset;
 616                     }
 617                     if (loc.end.line === 1) {
 618                         loc.end.column -= offset;
 619                     }
 620                 },
 621                 k,
 622                 obj,
 623                 i,
 624                 locations;
 625
 626             obj = coverState.statementMap;
 627             for (k in obj) {
 628                 /* istanbul ignore else: has own property */
 629                 if (obj.hasOwnProperty(k)) { fixer(obj[k]); }
 630             }
 631             obj = coverState.fnMap;
 632             for (k in obj) {
 633                 /* istanbul ignore else: has own property */
 634                 if (obj.hasOwnProperty(k)) { fixer(obj[k].loc); }
 635             }
 636             obj = coverState.branchMap;
 637             for (k in obj) {
 638                 /* istanbul ignore else: has own property */
 639                 if (obj.hasOwnProperty(k)) {
 640                     locations = obj[k].locations;
 641                     for (i = 0; i < locations.length; i += 1) {
 642                         fixer(locations[i]);
 643                     }
 644                 }
 645             }
 646         },
 647
 648         getPreamble: function (sourceCode, emitUseStrict) {
 649             var varName = this.opts.coverageVariable || '__coverage__',
 650                 file = this.coverState.path.replace(/\\/g, '\\\\'),
 651                 tracker = this.currentState.trackerVar,
 652                 coverState,
 653                 strictLine = emitUseStrict ? '"use strict";' : '',
 654                 // return replacements using the function to ensure that the replacement is
 655                 // treated like a dumb string and not as a string with RE replacement patterns
 656                 replacer = function (s) {
 657                     return function () { return s; };
 658                 },
 659                 code;
 660             if (!this.opts.noAutoWrap) {
 661                 this.fixColumnPositions(this.coverState);
 662             }
 663             if (this.opts.embedSource) {
 664                 this.coverState.code = sourceCode.split(/(?:\r?\n)|\r/);
 665             }
 666             coverState = this.opts.debug ? JSON.stringify(this.coverState, undefined, 4) : JSON.stringify(this.coverState);
 667             code = [
 668                 "%STRICT%",
 669                 "var %VAR% = (Function('return this'))();",
 670                 "if (!%VAR%.%GLOBAL%) { %VAR%.%GLOBAL% = {}; }",
 671                 "%VAR% = %VAR%.%GLOBAL%;",
 672                 "if (!(%VAR%['%FILE%'])) {",
 673                 "   %VAR%['%FILE%'] = %OBJECT%;",
 674                 "}",
 675                 "%VAR% = %VAR%['%FILE%'];"
 676             ].join("\n")
 677                 .replace(/%STRICT%/g, replacer(strictLine))
 678                 .replace(/%VAR%/g, replacer(tracker))
 679                 .replace(/%GLOBAL%/g, replacer(varName))
 680                 .replace(/%FILE%/g, replacer(file))
 681                 .replace(/%OBJECT%/g, replacer(coverState));
 682             return code;
 683         },
 684
 685         startIgnore: function () {
 686             this.currentState.ignoring += 1;
 687         },
 688
 689         endIgnore: function () {
 690             this.currentState.ignoring -= 1;
 691         },
 692
 693         convertToBlock: function (node) {
 694             if (!node) {
 695                 return { type: 'BlockStatement', body: [] };
 696             } else if (node.type === 'BlockStatement') {
 697                 return node;
 698             } else {
 699                 return { type: 'BlockStatement', body: [ node ] };
 700             }
 701         },
 702
 703         arrowBlockConverter: function (node) {
 704             var retStatement;
 705             if (node.expression) { // turn expression nodes into a block with a return statement
 706                 retStatement = astgen.returnStatement(node.body);
 707                 // ensure the generated return statement is covered
 708                 retStatement.loc = node.body.loc;
 709                 node.body = this.convertToBlock(retStatement);
 710                 node.expression = false;
 711             }
 712         },
 713
 714         paranoidHandlerCheck: function (node) {
 715             // if someone is using an older esprima on the browser
 716             // convert handlers array to single handler attribute
 717             // containing its first element
 718             /* istanbul ignore next */
 719             if (!node.handler && node.handlers) {
 720                 node.handler = node.handlers[0];
 721             }
 722         },
 723
 724         ifBlockConverter: function (node) {
 725             node.consequent = this.convertToBlock(node.consequent);
 726             node.alternate = this.convertToBlock(node.alternate);
 727         },
 728
 729         loopBlockConverter: function (node) {
 730             node.body = this.convertToBlock(node.body);
 731         },
 732
 733         withBlockConverter: function (node) {
 734             node.body = this.convertToBlock(node.body);
 735         },
 736
 737         statementName: function (location, initValue) {
 738             var sName,
 739                 ignoring = !!this.currentState.ignoring;
 740
 741             location.skip = ignoring || undefined;
 742             initValue = initValue || 0;
 743             this.currentState.statement += 1;
 744             sName = this.currentState.statement;
 745             this.coverState.statementMap[sName] = location;
 746             this.coverState.s[sName] = initValue;
 747             return sName;
 748         },
 749
 750         skipInit: function (node /*, walker */) {
 751             if (node.init) {
 752                 node.init.skipWalk = true;
 753             }
 754         },
 755
 756         skipLeft: function (node /*, walker */) {
 757             node.left.skipWalk = true;
 758         },
 759
 760         isUseStrictExpression: function (node) {
 761             return node && node.type === SYNTAX.ExpressionStatement.name &&
 762                 node.expression  && node.expression.type === SYNTAX.Literal.name &&
 763                 node.expression.value === 'use strict';
 764         },
 765
 766         maybeSkipNode: function (node, type) {
 767             var alreadyIgnoring = !!this.currentState.ignoring,
 768                 hint = this.currentState.currentHint,
 769                 ignoreThis = !alreadyIgnoring && hint && hint.type === type;
 770
 771             if (ignoreThis) {
 772                 this.startIgnore();
 773                 node.postprocessor = this.endIgnore;
 774                 return true;
 775             }
 776             return false;
 777         },
 778
 779         coverStatement: function (node, walker) {
 780             var sName,
 781                 incrStatementCount,
 782                 grandParent;
 783
 784             this.maybeSkipNode(node, 'next');
 785
 786             if (this.isUseStrictExpression(node)) {
 787                 grandParent = walker.ancestor(2);
 788                 /* istanbul ignore else: difficult to test */
 789                 if (grandParent) {
 790                     if ((grandParent.node.type === SYNTAX.FunctionExpression.name ||
 791                         grandParent.node.type === SYNTAX.FunctionDeclaration.name)  &&
 792                         walker.parent().node.body[0] === node) {
 793                         return;
 794                     }
 795                 }
 796             }
 797             if (node.type === SYNTAX.FunctionDeclaration.name) {
 798                 sName = this.statementName(node.loc, 1);
 799             } else {
 800                 sName = this.statementName(node.loc);
 801                 incrStatementCount = astgen.statement(
 802                     astgen.postIncrement(
 803                         astgen.subscript(
 804                             astgen.dot(astgen.variable(this.currentState.trackerVar), astgen.variable('s')),
 805                             astgen.stringLiteral(sName)
 806                         )
 807                     )
 808                 );
 809                 this.splice(incrStatementCount, node, walker);
 810             }
 811         },
 812
 813         splice: function (statements, node, walker) {
 814             var targetNode = walker.isLabeled() ? walker.parent().node : node;
 815             targetNode.prepend = targetNode.prepend || [];
 816             pushAll(targetNode.prepend, statements);
 817         },
 818
 819         functionName: function (node, line, location) {
 820             this.currentState.func += 1;
 821             var id = this.currentState.func,
 822                 ignoring = !!this.currentState.ignoring,
 823                 name = node.id ? node.id.name : '(anonymous_' + id + ')',
 824                 clone = function (attr) {
 825                     var obj = location[attr] || /* istanbul ignore next */ {};
 826                     return { line: obj.line, column: obj.column };
 827                 };
 828             this.coverState.fnMap[id] = {
 829                 name: name, line: line,
 830                 loc: {
 831                     start: clone('start'),
 832                     end: clone('end')
 833                 },
 834                 skip: ignoring || undefined
 835             };
 836             this.coverState.f[id] = 0;
 837             return id;
 838         },
 839
 840         coverFunction: function (node, walker) {
 841             var id,
 842                 body = node.body,
 843                 blockBody = body.body,
 844                 popped;
 845
 846             this.maybeSkipNode(node, 'next');
 847
 848             id = this.functionName(node, walker.startLineForNode(node), {
 849                 start: node.loc.start,
 850                 end: { line: node.body.loc.start.line, column: node.body.loc.start.column }
 851             });
 852
 853             if (blockBody.length > 0 && this.isUseStrictExpression(blockBody[0])) {
 854                 popped = blockBody.shift();
 855             }
 856             blockBody.unshift(
 857                 astgen.statement(
 858                     astgen.postIncrement(
 859                         astgen.subscript(
 860                             astgen.dot(astgen.variable(this.currentState.trackerVar), astgen.variable('f')),
 861                             astgen.stringLiteral(id)
 862                         )
 863                     )
 864                 )
 865             );
 866             if (popped) {
 867                 blockBody.unshift(popped);
 868             }
 869         },
 870
 871         branchName: function (type, startLine, pathLocations) {
 872             var bName,
 873                 paths = [],
 874                 locations = [],
 875                 i,
 876                 ignoring = !!this.currentState.ignoring;
 877             this.currentState.branch += 1;
 878             bName = this.currentState.branch;
 879             for (i = 0; i < pathLocations.length; i += 1) {
 880                 pathLocations[i].skip = pathLocations[i].skip || ignoring || undefined;
 881                 locations.push(pathLocations[i]);
 882                 paths.push(0);
 883             }
 884             this.coverState.b[bName] = paths;
 885             this.coverState.branchMap[bName] = { line: startLine, type: type, locations: locations };
 886             return bName;
 887         },
 888
 889         branchIncrementExprAst: function (varName, branchIndex, down) {
 890             var ret = astgen.postIncrement(
 891                 astgen.subscript(
 892                     astgen.subscript(
 893                         astgen.dot(astgen.variable(this.currentState.trackerVar), astgen.variable('b')),
 894                         astgen.stringLiteral(varName)
 895                     ),
 896                     astgen.numericLiteral(branchIndex)
 897                 ),
 898                 down
 899             );
 900             return ret;
 901         },
 902
 903         locationsForNodes: function (nodes) {
 904             var ret = [],
 905                 i;
 906             for (i = 0; i < nodes.length; i += 1) {
 907                 ret.push(nodes[i].loc);
 908             }
 909             return ret;
 910         },
 911
 912         ifBranchInjector: function (node, walker) {
 913             var alreadyIgnoring = !!this.currentState.ignoring,
 914                 hint = this.currentState.currentHint,
 915                 ignoreThen = !alreadyIgnoring && hint && hint.type === 'if',
 916                 ignoreElse = !alreadyIgnoring && hint && hint.type === 'else',
 917                 line = node.loc.start.line,
 918                 col = node.loc.start.column,
 919                 makeLoc = function () { return  { line: line, column: col }; },
 920                 bName = this.branchName('if', walker.startLineForNode(node), [
 921                     { start: makeLoc(), end: makeLoc(), skip: ignoreThen || undefined },
 922                     { start: makeLoc(), end: makeLoc(), skip: ignoreElse || undefined }
 923                 ]),
 924                 thenBody = node.consequent.body,
 925                 elseBody = node.alternate.body,
 926                 child;
 927             thenBody.unshift(astgen.statement(this.branchIncrementExprAst(bName, 0)));
 928             elseBody.unshift(astgen.statement(this.branchIncrementExprAst(bName, 1)));
 929             if (ignoreThen) { child = node.consequent; child.preprocessor = this.startIgnore; child.postprocessor = this.endIgnore; }
 930             if (ignoreElse) { child = node.alternate; child.preprocessor = this.startIgnore; child.postprocessor = this.endIgnore; }
 931         },
 932
 933         branchLocationFor: function (name, index) {
 934             return this.coverState.branchMap[name].locations[index];
 935         },
 936
 937         switchBranchInjector: function (node, walker) {
 938             var cases = node.cases,
 939                 bName,
 940                 i;
 941
 942             if (!(cases && cases.length > 0)) {
 943                 return;
 944             }
 945             bName = this.branchName('switch', walker.startLineForNode(node), this.locationsForNodes(cases));
 946             for (i = 0; i < cases.length; i += 1) {
 947                 cases[i].branchLocation = this.branchLocationFor(bName, i);
 948                 cases[i].consequent.unshift(astgen.statement(this.branchIncrementExprAst(bName, i)));
 949             }
 950         },
 951
 952         switchCaseInjector: function (node) {
 953             var location = node.branchLocation;
 954             delete node.branchLocation;
 955             if (this.maybeSkipNode(node, 'next')) {
 956                 location.skip = true;
 957             }
 958         },
 959
 960         conditionalBranchInjector: function (node, walker) {
 961             var bName = this.branchName('cond-expr', walker.startLineForNode(node), this.locationsForNodes([ node.consequent, node.alternate ])),
 962                 ast1 = this.branchIncrementExprAst(bName, 0),
 963                 ast2 = this.branchIncrementExprAst(bName, 1);
 964
 965             node.consequent.preprocessor = this.maybeAddSkip(this.branchLocationFor(bName, 0));
 966             node.alternate.preprocessor = this.maybeAddSkip(this.branchLocationFor(bName, 1));
 967             node.consequent = astgen.sequence(ast1, node.consequent);
 968             node.alternate = astgen.sequence(ast2, node.alternate);
 969         },
 970
 971         maybeAddSkip: function (branchLocation) {
 972             return function (node) {
 973                 var alreadyIgnoring = !!this.currentState.ignoring,
 974                     hint = this.currentState.currentHint,
 975                     ignoreThis = !alreadyIgnoring && hint && hint.type === 'next';
 976                 if (ignoreThis) {
 977                     this.startIgnore();
 978                     node.postprocessor = this.endIgnore;
 979                 }
 980                 if (ignoreThis || alreadyIgnoring) {
 981                     branchLocation.skip = true;
 982                 }
 983             };
 984         },
 985
 986         logicalExpressionBranchInjector: function (node, walker) {
 987             var parent = walker.parent(),
 988                 leaves = [],
 989                 bName,
 990                 tuple,
 991                 i;
 992
 993             this.maybeSkipNode(node, 'next');
 994
 995             if (parent && parent.node.type === SYNTAX.LogicalExpression.name) {
 996                 //already covered
 997                 return;
 998             }
 999
1000             this.findLeaves(node, leaves);
1001             bName = this.branchName('binary-expr',
1002                 walker.startLineForNode(node),
1003                 this.locationsForNodes(leaves.map(function (item) { return item.node; }))
1004             );
1005             for (i = 0; i < leaves.length; i += 1) {
1006                 tuple = leaves[i];
1007                 tuple.parent[tuple.property] = astgen.sequence(this.branchIncrementExprAst(bName, i), tuple.node);
1008                 tuple.node.preprocessor = this.maybeAddSkip(this.branchLocationFor(bName, i));
1009             }
1010         },
1011
1012         findLeaves: function (node, accumulator, parent, property) {
1013             if (node.type === SYNTAX.LogicalExpression.name) {
1014                 this.findLeaves(node.left, accumulator, node, 'left');
1015                 this.findLeaves(node.right, accumulator, node, 'right');
1016             } else {
1017                 accumulator.push({ node: node, parent: parent, property: property });
1018             }
1019         },
1020         maybeAddType: function (node /*, walker */) {
1021             var props = node.properties,
1022                 i,
1023                 child;
1024             for (i = 0; i < props.length; i += 1) {
1025                 child = props[i];
1026                 if (!child.type) {
1027                     child.type = SYNTAX.Property.name;
1028                 }
1029             }
1030         }
1031     };
1032
1033     if (isNode) {
1034         module.exports = Instrumenter;
1035     } else {
1036         window.Instrumenter = Instrumenter;
1037     }
1038
1039 }(typeof module !== 'undefined' && typeof module.exports !== 'undefined' && typeof exports !== 'undefined'));
1040