| 1 | 'use strict'; |
| 2 | |
| 3 | /* eslint-disable react-internal/no-primitive-constructors */ |
| 4 | |
| 5 | //------------------------------------------------------------------------------ |
| 6 | // Requirements |
| 7 | //------------------------------------------------------------------------------ |
| 8 | |
| 9 | // eslint-disable-next-line |
| 10 | const assert = require('./assert'); |
| 11 | // eslint-disable-next-line |
| 12 | const CodePath = require('./code-path'); |
| 13 | // eslint-disable-next-line |
| 14 | const CodePathSegment = require('./code-path-segment'); |
| 15 | // eslint-disable-next-line |
| 16 | const IdGenerator = require('./id-generator'); |
| 17 | |
| 18 | const breakableTypePattern = |
| 19 | /^(?:(?:Do)?While|For(?:In|Of)?|Switch)Statement$/u; |
| 20 | |
| 21 | //------------------------------------------------------------------------------ |
| 22 | // Helpers |
| 23 | //------------------------------------------------------------------------------ |
| 24 | |
| 25 | /** |
| 26 | * Checks whether or not a given node is a `case` node (not `default` node). |
| 27 | * @param {ASTNode} node A `SwitchCase` node to check. |
| 28 | * @returns {boolean} `true` if the node is a `case` node (not `default` node). |
| 29 | */ |
| 30 | function isCaseNode(node) { |
| 31 | return Boolean(node.test); |
| 32 | } |
| 33 | |
| 34 | /** |
| 35 | * Checks if a given node appears as the value of a PropertyDefinition node. |
| 36 | * @param {ASTNode} node THe node to check. |
| 37 | * @returns {boolean} `true` if the node is a PropertyDefinition value, |
| 38 | * false if not. |
| 39 | */ |
| 40 | function isPropertyDefinitionValue(node) { |
| 41 | const parent = node.parent; |
| 42 | |
| 43 | return ( |
| 44 | parent && parent.type === 'PropertyDefinition' && parent.value === node |
| 45 | ); |
| 46 | } |
| 47 | |
| 48 | /** |
| 49 | * Checks whether the given logical operator is taken into account for the code |
| 50 | * path analysis. |
| 51 | * @param {string} operator The operator found in the LogicalExpression node |
| 52 | * @returns {boolean} `true` if the operator is "&&" or "||" or "??" |
| 53 | */ |
| 54 | function isHandledLogicalOperator(operator) { |
| 55 | return operator === '&&' || operator === '||' || operator === '??'; |
| 56 | } |
| 57 | |
| 58 | /** |
| 59 | * Checks whether the given assignment operator is a logical assignment operator. |
| 60 | * Logical assignments are taken into account for the code path analysis |
| 61 | * because of their short-circuiting semantics. |
| 62 | * @param {string} operator The operator found in the AssignmentExpression node |
| 63 | * @returns {boolean} `true` if the operator is "&&=" or "||=" or "??=" |
| 64 | */ |
| 65 | function isLogicalAssignmentOperator(operator) { |
| 66 | return operator === '&&=' || operator === '||=' || operator === '??='; |
| 67 | } |
| 68 | |
| 69 | /** |
| 70 | * Gets the label if the parent node of a given node is a LabeledStatement. |
| 71 | * @param {ASTNode} node A node to get. |
| 72 | * @returns {string|null} The label or `null`. |
| 73 | */ |
| 74 | function getLabel(node) { |
| 75 | if (node.parent.type === 'LabeledStatement') { |
| 76 | return node.parent.label.name; |
| 77 | } |
| 78 | return null; |
| 79 | } |
| 80 | |
| 81 | /** |
| 82 | * Checks whether or not a given logical expression node goes different path |
| 83 | * between the `true` case and the `false` case. |
| 84 | * @param {ASTNode} node A node to check. |
| 85 | * @returns {boolean} `true` if the node is a test of a choice statement. |
| 86 | */ |
| 87 | function isForkingByTrueOrFalse(node) { |
| 88 | const parent = node.parent; |
| 89 | |
| 90 | switch (parent.type) { |
| 91 | case 'ConditionalExpression': |
| 92 | case 'IfStatement': |
| 93 | case 'WhileStatement': |
| 94 | case 'DoWhileStatement': |
| 95 | case 'ForStatement': |
| 96 | return parent.test === node; |
| 97 | |
| 98 | case 'LogicalExpression': |
| 99 | return isHandledLogicalOperator(parent.operator); |
| 100 | |
| 101 | case 'AssignmentExpression': |
| 102 | return isLogicalAssignmentOperator(parent.operator); |
| 103 | |
| 104 | default: |
| 105 | return false; |
| 106 | } |
| 107 | } |
| 108 | |
| 109 | /** |
| 110 | * Gets the boolean value of a given literal node. |
| 111 | * |
| 112 | * This is used to detect infinity loops (e.g. `while (true) {}`). |
| 113 | * Statements preceded by an infinity loop are unreachable if the loop didn't |
| 114 | * have any `break` statement. |
| 115 | * @param {ASTNode} node A node to get. |
| 116 | * @returns {boolean|undefined} a boolean value if the node is a Literal node, |
| 117 | * otherwise `undefined`. |
| 118 | */ |
| 119 | function getBooleanValueIfSimpleConstant(node) { |
| 120 | if (node.type === 'Literal') { |
| 121 | return Boolean(node.value); |
| 122 | } |
| 123 | return void 0; |
| 124 | } |
| 125 | |
| 126 | /** |
| 127 | * Checks that a given identifier node is a reference or not. |
| 128 | * |
| 129 | * This is used to detect the first throwable node in a `try` block. |
| 130 | * @param {ASTNode} node An Identifier node to check. |
| 131 | * @returns {boolean} `true` if the node is a reference. |
| 132 | */ |
| 133 | function isIdentifierReference(node) { |
| 134 | const parent = node.parent; |
| 135 | |
| 136 | switch (parent.type) { |
| 137 | case 'LabeledStatement': |
| 138 | case 'BreakStatement': |
| 139 | case 'ContinueStatement': |
| 140 | case 'ArrayPattern': |
| 141 | case 'RestElement': |
| 142 | case 'ImportSpecifier': |
| 143 | case 'ImportDefaultSpecifier': |
| 144 | case 'ImportNamespaceSpecifier': |
| 145 | case 'CatchClause': |
| 146 | return false; |
| 147 | |
| 148 | case 'FunctionDeclaration': |
| 149 | case 'ComponentDeclaration': |
| 150 | case 'HookDeclaration': |
| 151 | case 'FunctionExpression': |
| 152 | case 'ArrowFunctionExpression': |
| 153 | case 'ClassDeclaration': |
| 154 | case 'ClassExpression': |
| 155 | case 'VariableDeclarator': |
| 156 | return parent.id !== node; |
| 157 | |
| 158 | case 'Property': |
| 159 | case 'PropertyDefinition': |
| 160 | case 'MethodDefinition': |
| 161 | return parent.key !== node || parent.computed || parent.shorthand; |
| 162 | |
| 163 | case 'AssignmentPattern': |
| 164 | return parent.key !== node; |
| 165 | |
| 166 | default: |
| 167 | return true; |
| 168 | } |
| 169 | } |
| 170 | |
| 171 | /** |
| 172 | * Updates the current segment with the head segment. |
| 173 | * This is similar to local branches and tracking branches of git. |
| 174 | * |
| 175 | * To separate the current and the head is in order to not make useless segments. |
| 176 | * |
| 177 | * In this process, both "onCodePathSegmentStart" and "onCodePathSegmentEnd" |
| 178 | * events are fired. |
| 179 | * @param {CodePathAnalyzer} analyzer The instance. |
| 180 | * @param {ASTNode} node The current AST node. |
| 181 | * @returns {void} |
| 182 | */ |
| 183 | function forwardCurrentToHead(analyzer, node) { |
| 184 | const codePath = analyzer.codePath; |
| 185 | const state = CodePath.getState(codePath); |
| 186 | const currentSegments = state.currentSegments; |
| 187 | const headSegments = state.headSegments; |
| 188 | const end = Math.max(currentSegments.length, headSegments.length); |
| 189 | let i, currentSegment, headSegment; |
| 190 | |
| 191 | // Fires leaving events. |
| 192 | for (i = 0; i < end; ++i) { |
| 193 | currentSegment = currentSegments[i]; |
| 194 | headSegment = headSegments[i]; |
| 195 | |
| 196 | if (currentSegment !== headSegment && currentSegment) { |
| 197 | if (currentSegment.reachable) { |
| 198 | analyzer.emitter.emit('onCodePathSegmentEnd', currentSegment, node); |
| 199 | } |
| 200 | } |
| 201 | } |
| 202 | |
| 203 | // Update state. |
| 204 | state.currentSegments = headSegments; |
| 205 | |
| 206 | // Fires entering events. |
| 207 | for (i = 0; i < end; ++i) { |
| 208 | currentSegment = currentSegments[i]; |
| 209 | headSegment = headSegments[i]; |
| 210 | |
| 211 | if (currentSegment !== headSegment && headSegment) { |
| 212 | CodePathSegment.markUsed(headSegment); |
| 213 | if (headSegment.reachable) { |
| 214 | analyzer.emitter.emit('onCodePathSegmentStart', headSegment, node); |
| 215 | } |
| 216 | } |
| 217 | } |
| 218 | } |
| 219 | |
| 220 | /** |
| 221 | * Updates the current segment with empty. |
| 222 | * This is called at the last of functions or the program. |
| 223 | * @param {CodePathAnalyzer} analyzer The instance. |
| 224 | * @param {ASTNode} node The current AST node. |
| 225 | * @returns {void} |
| 226 | */ |
| 227 | function leaveFromCurrentSegment(analyzer, node) { |
| 228 | const state = CodePath.getState(analyzer.codePath); |
| 229 | const currentSegments = state.currentSegments; |
| 230 | |
| 231 | for (let i = 0; i < currentSegments.length; ++i) { |
| 232 | const currentSegment = currentSegments[i]; |
| 233 | if (currentSegment.reachable) { |
| 234 | analyzer.emitter.emit('onCodePathSegmentEnd', currentSegment, node); |
| 235 | } |
| 236 | } |
| 237 | |
| 238 | state.currentSegments = []; |
| 239 | } |
| 240 | |
| 241 | /** |
| 242 | * Updates the code path due to the position of a given node in the parent node |
| 243 | * thereof. |
| 244 | * |
| 245 | * For example, if the node is `parent.consequent`, this creates a fork from the |
| 246 | * current path. |
| 247 | * @param {CodePathAnalyzer} analyzer The instance. |
| 248 | * @param {ASTNode} node The current AST node. |
| 249 | * @returns {void} |
| 250 | */ |
| 251 | function preprocess(analyzer, node) { |
| 252 | const codePath = analyzer.codePath; |
| 253 | const state = CodePath.getState(codePath); |
| 254 | const parent = node.parent; |
| 255 | |
| 256 | switch (parent.type) { |
| 257 | // The `arguments.length == 0` case is in `postprocess` function. |
| 258 | case 'CallExpression': |
| 259 | if ( |
| 260 | parent.optional === true && |
| 261 | parent.arguments.length >= 1 && |
| 262 | parent.arguments[0] === node |
| 263 | ) { |
| 264 | state.makeOptionalRight(); |
| 265 | } |
| 266 | break; |
| 267 | case 'MemberExpression': |
| 268 | if (parent.optional === true && parent.property === node) { |
| 269 | state.makeOptionalRight(); |
| 270 | } |
| 271 | break; |
| 272 | |
| 273 | case 'LogicalExpression': |
| 274 | if (parent.right === node && isHandledLogicalOperator(parent.operator)) { |
| 275 | state.makeLogicalRight(); |
| 276 | } |
| 277 | break; |
| 278 | |
| 279 | case 'AssignmentExpression': |
| 280 | if ( |
| 281 | parent.right === node && |
| 282 | isLogicalAssignmentOperator(parent.operator) |
| 283 | ) { |
| 284 | state.makeLogicalRight(); |
| 285 | } |
| 286 | break; |
| 287 | |
| 288 | case 'ConditionalExpression': |
| 289 | case 'IfStatement': |
| 290 | /* |
| 291 | * Fork if this node is at `consequent`/`alternate`. |
| 292 | * `popForkContext()` exists at `IfStatement:exit` and |
| 293 | * `ConditionalExpression:exit`. |
| 294 | */ |
| 295 | if (parent.consequent === node) { |
| 296 | state.makeIfConsequent(); |
| 297 | } else if (parent.alternate === node) { |
| 298 | state.makeIfAlternate(); |
| 299 | } |
| 300 | break; |
| 301 | |
| 302 | case 'SwitchCase': |
| 303 | if (parent.consequent[0] === node) { |
| 304 | state.makeSwitchCaseBody(false, !parent.test); |
| 305 | } |
| 306 | break; |
| 307 | |
| 308 | case 'TryStatement': |
| 309 | if (parent.handler === node) { |
| 310 | state.makeCatchBlock(); |
| 311 | } else if (parent.finalizer === node) { |
| 312 | state.makeFinallyBlock(); |
| 313 | } |
| 314 | break; |
| 315 | |
| 316 | case 'WhileStatement': |
| 317 | if (parent.test === node) { |
| 318 | state.makeWhileTest(getBooleanValueIfSimpleConstant(node)); |
| 319 | } else { |
| 320 | assert(parent.body === node); |
| 321 | state.makeWhileBody(); |
| 322 | } |
| 323 | break; |
| 324 | |
| 325 | case 'DoWhileStatement': |
| 326 | if (parent.body === node) { |
| 327 | state.makeDoWhileBody(); |
| 328 | } else { |
| 329 | assert(parent.test === node); |
| 330 | state.makeDoWhileTest(getBooleanValueIfSimpleConstant(node)); |
| 331 | } |
| 332 | break; |
| 333 | |
| 334 | case 'ForStatement': |
| 335 | if (parent.test === node) { |
| 336 | state.makeForTest(getBooleanValueIfSimpleConstant(node)); |
| 337 | } else if (parent.update === node) { |
| 338 | state.makeForUpdate(); |
| 339 | } else if (parent.body === node) { |
| 340 | state.makeForBody(); |
| 341 | } |
| 342 | break; |
| 343 | |
| 344 | case 'ForInStatement': |
| 345 | case 'ForOfStatement': |
| 346 | if (parent.left === node) { |
| 347 | state.makeForInOfLeft(); |
| 348 | } else if (parent.right === node) { |
| 349 | state.makeForInOfRight(); |
| 350 | } else { |
| 351 | assert(parent.body === node); |
| 352 | state.makeForInOfBody(); |
| 353 | } |
| 354 | break; |
| 355 | |
| 356 | case 'AssignmentPattern': |
| 357 | /* |
| 358 | * Fork if this node is at `right`. |
| 359 | * `left` is executed always, so it uses the current path. |
| 360 | * `popForkContext()` exists at `AssignmentPattern:exit`. |
| 361 | */ |
| 362 | if (parent.right === node) { |
| 363 | state.pushForkContext(); |
| 364 | state.forkBypassPath(); |
| 365 | state.forkPath(); |
| 366 | } |
| 367 | break; |
| 368 | |
| 369 | default: |
| 370 | break; |
| 371 | } |
| 372 | } |
| 373 | |
| 374 | /** |
| 375 | * Updates the code path due to the type of a given node in entering. |
| 376 | * @param {CodePathAnalyzer} analyzer The instance. |
| 377 | * @param {ASTNode} node The current AST node. |
| 378 | * @returns {void} |
| 379 | */ |
| 380 | function processCodePathToEnter(analyzer, node) { |
| 381 | let codePath = analyzer.codePath; |
| 382 | let state = codePath && CodePath.getState(codePath); |
| 383 | const parent = node.parent; |
| 384 | |
| 385 | /** |
| 386 | * Creates a new code path and trigger the onCodePathStart event |
| 387 | * based on the currently selected node. |
| 388 | * @param {string} origin The reason the code path was started. |
| 389 | * @returns {void} |
| 390 | */ |
| 391 | function startCodePath(origin) { |
| 392 | if (codePath) { |
| 393 | // Emits onCodePathSegmentStart events if updated. |
| 394 | forwardCurrentToHead(analyzer, node); |
| 395 | } |
| 396 | |
| 397 | // Create the code path of this scope. |
| 398 | codePath = analyzer.codePath = new CodePath({ |
| 399 | id: analyzer.idGenerator.next(), |
| 400 | origin, |
| 401 | upper: codePath, |
| 402 | onLooped: analyzer.onLooped, |
| 403 | }); |
| 404 | state = CodePath.getState(codePath); |
| 405 | |
| 406 | // Emits onCodePathStart events. |
| 407 | analyzer.emitter.emit('onCodePathStart', codePath, node); |
| 408 | } |
| 409 | |
| 410 | /* |
| 411 | * Special case: The right side of class field initializer is considered |
| 412 | * to be its own function, so we need to start a new code path in this |
| 413 | * case. |
| 414 | */ |
| 415 | if (isPropertyDefinitionValue(node)) { |
| 416 | startCodePath('class-field-initializer'); |
| 417 | |
| 418 | /* |
| 419 | * Intentional fall through because `node` needs to also be |
| 420 | * processed by the code below. For example, if we have: |
| 421 | * |
| 422 | * class Foo { |
| 423 | * a = () => {} |
| 424 | * } |
| 425 | * |
| 426 | * In this case, we also need start a second code path. |
| 427 | */ |
| 428 | } |
| 429 | |
| 430 | switch (node.type) { |
| 431 | case 'Program': |
| 432 | startCodePath('program'); |
| 433 | break; |
| 434 | |
| 435 | case 'FunctionDeclaration': |
| 436 | case 'ComponentDeclaration': |
| 437 | case 'HookDeclaration': |
| 438 | case 'FunctionExpression': |
| 439 | case 'ArrowFunctionExpression': |
| 440 | startCodePath('function'); |
| 441 | break; |
| 442 | |
| 443 | case 'StaticBlock': |
| 444 | startCodePath('class-static-block'); |
| 445 | break; |
| 446 | |
| 447 | case 'ChainExpression': |
| 448 | state.pushChainContext(); |
| 449 | break; |
| 450 | case 'CallExpression': |
| 451 | if (node.optional === true) { |
| 452 | state.makeOptionalNode(); |
| 453 | } |
| 454 | break; |
| 455 | case 'MemberExpression': |
| 456 | if (node.optional === true) { |
| 457 | state.makeOptionalNode(); |
| 458 | } |
| 459 | break; |
| 460 | |
| 461 | case 'LogicalExpression': |
| 462 | if (isHandledLogicalOperator(node.operator)) { |
| 463 | state.pushChoiceContext(node.operator, isForkingByTrueOrFalse(node)); |
| 464 | } |
| 465 | break; |
| 466 | |
| 467 | case 'AssignmentExpression': |
| 468 | if (isLogicalAssignmentOperator(node.operator)) { |
| 469 | state.pushChoiceContext( |
| 470 | node.operator.slice(0, -1), // removes `=` from the end |
| 471 | isForkingByTrueOrFalse(node), |
| 472 | ); |
| 473 | } |
| 474 | break; |
| 475 | |
| 476 | case 'ConditionalExpression': |
| 477 | case 'IfStatement': |
| 478 | state.pushChoiceContext('test', false); |
| 479 | break; |
| 480 | |
| 481 | case 'SwitchStatement': |
| 482 | state.pushSwitchContext(node.cases.some(isCaseNode), getLabel(node)); |
| 483 | break; |
| 484 | |
| 485 | case 'TryStatement': |
| 486 | state.pushTryContext(Boolean(node.finalizer)); |
| 487 | break; |
| 488 | |
| 489 | case 'SwitchCase': |
| 490 | /* |
| 491 | * Fork if this node is after the 2st node in `cases`. |
| 492 | * It's similar to `else` blocks. |
| 493 | * The next `test` node is processed in this path. |
| 494 | */ |
| 495 | if (parent.discriminant !== node && parent.cases[0] !== node) { |
| 496 | state.forkPath(); |
| 497 | } |
| 498 | break; |
| 499 | |
| 500 | case 'WhileStatement': |
| 501 | case 'DoWhileStatement': |
| 502 | case 'ForStatement': |
| 503 | case 'ForInStatement': |
| 504 | case 'ForOfStatement': |
| 505 | state.pushLoopContext(node.type, getLabel(node)); |
| 506 | break; |
| 507 | |
| 508 | case 'LabeledStatement': |
| 509 | if (!breakableTypePattern.test(node.body.type)) { |
| 510 | state.pushBreakContext(false, node.label.name); |
| 511 | } |
| 512 | break; |
| 513 | |
| 514 | default: |
| 515 | break; |
| 516 | } |
| 517 | |
| 518 | // Emits onCodePathSegmentStart events if updated. |
| 519 | forwardCurrentToHead(analyzer, node); |
| 520 | } |
| 521 | |
| 522 | /** |
| 523 | * Updates the code path due to the type of a given node in leaving. |
| 524 | * @param {CodePathAnalyzer} analyzer The instance. |
| 525 | * @param {ASTNode} node The current AST node. |
| 526 | * @returns {void} |
| 527 | */ |
| 528 | function processCodePathToExit(analyzer, node) { |
| 529 | const codePath = analyzer.codePath; |
| 530 | const state = CodePath.getState(codePath); |
| 531 | let dontForward = false; |
| 532 | |
| 533 | switch (node.type) { |
| 534 | case 'ChainExpression': |
| 535 | state.popChainContext(); |
| 536 | break; |
| 537 | |
| 538 | case 'IfStatement': |
| 539 | case 'ConditionalExpression': |
| 540 | state.popChoiceContext(); |
| 541 | break; |
| 542 | |
| 543 | case 'LogicalExpression': |
| 544 | if (isHandledLogicalOperator(node.operator)) { |
| 545 | state.popChoiceContext(); |
| 546 | } |
| 547 | break; |
| 548 | |
| 549 | case 'AssignmentExpression': |
| 550 | if (isLogicalAssignmentOperator(node.operator)) { |
| 551 | state.popChoiceContext(); |
| 552 | } |
| 553 | break; |
| 554 | |
| 555 | case 'SwitchStatement': |
| 556 | state.popSwitchContext(); |
| 557 | break; |
| 558 | |
| 559 | case 'SwitchCase': |
| 560 | /* |
| 561 | * This is the same as the process at the 1st `consequent` node in |
| 562 | * `preprocess` function. |
| 563 | * Must do if this `consequent` is empty. |
| 564 | */ |
| 565 | if (node.consequent.length === 0) { |
| 566 | state.makeSwitchCaseBody(true, !node.test); |
| 567 | } |
| 568 | if (state.forkContext.reachable) { |
| 569 | dontForward = true; |
| 570 | } |
| 571 | break; |
| 572 | |
| 573 | case 'TryStatement': |
| 574 | state.popTryContext(); |
| 575 | break; |
| 576 | |
| 577 | case 'BreakStatement': |
| 578 | forwardCurrentToHead(analyzer, node); |
| 579 | state.makeBreak(node.label && node.label.name); |
| 580 | dontForward = true; |
| 581 | break; |
| 582 | |
| 583 | case 'ContinueStatement': |
| 584 | forwardCurrentToHead(analyzer, node); |
| 585 | state.makeContinue(node.label && node.label.name); |
| 586 | dontForward = true; |
| 587 | break; |
| 588 | |
| 589 | case 'ReturnStatement': |
| 590 | forwardCurrentToHead(analyzer, node); |
| 591 | state.makeReturn(); |
| 592 | dontForward = true; |
| 593 | break; |
| 594 | |
| 595 | case 'ThrowStatement': |
| 596 | forwardCurrentToHead(analyzer, node); |
| 597 | state.makeThrow(); |
| 598 | dontForward = true; |
| 599 | break; |
| 600 | |
| 601 | case 'Identifier': |
| 602 | if (isIdentifierReference(node)) { |
| 603 | state.makeFirstThrowablePathInTryBlock(); |
| 604 | dontForward = true; |
| 605 | } |
| 606 | break; |
| 607 | |
| 608 | case 'CallExpression': |
| 609 | case 'ImportExpression': |
| 610 | case 'MemberExpression': |
| 611 | case 'NewExpression': |
| 612 | case 'YieldExpression': |
| 613 | state.makeFirstThrowablePathInTryBlock(); |
| 614 | break; |
| 615 | |
| 616 | case 'WhileStatement': |
| 617 | case 'DoWhileStatement': |
| 618 | case 'ForStatement': |
| 619 | case 'ForInStatement': |
| 620 | case 'ForOfStatement': |
| 621 | state.popLoopContext(); |
| 622 | break; |
| 623 | |
| 624 | case 'AssignmentPattern': |
| 625 | state.popForkContext(); |
| 626 | break; |
| 627 | |
| 628 | case 'LabeledStatement': |
| 629 | if (!breakableTypePattern.test(node.body.type)) { |
| 630 | state.popBreakContext(); |
| 631 | } |
| 632 | break; |
| 633 | |
| 634 | default: |
| 635 | break; |
| 636 | } |
| 637 | |
| 638 | // Emits onCodePathSegmentStart events if updated. |
| 639 | if (!dontForward) { |
| 640 | forwardCurrentToHead(analyzer, node); |
| 641 | } |
| 642 | } |
| 643 | |
| 644 | /** |
| 645 | * Updates the code path to finalize the current code path. |
| 646 | * @param {CodePathAnalyzer} analyzer The instance. |
| 647 | * @param {ASTNode} node The current AST node. |
| 648 | * @returns {void} |
| 649 | */ |
| 650 | function postprocess(analyzer, node) { |
| 651 | /** |
| 652 | * Ends the code path for the current node. |
| 653 | * @returns {void} |
| 654 | */ |
| 655 | function endCodePath() { |
| 656 | let codePath = analyzer.codePath; |
| 657 | |
| 658 | // Mark the current path as the final node. |
| 659 | CodePath.getState(codePath).makeFinal(); |
| 660 | |
| 661 | // Emits onCodePathSegmentEnd event of the current segments. |
| 662 | leaveFromCurrentSegment(analyzer, node); |
| 663 | |
| 664 | // Emits onCodePathEnd event of this code path. |
| 665 | analyzer.emitter.emit('onCodePathEnd', codePath, node); |
| 666 | |
| 667 | codePath = analyzer.codePath = analyzer.codePath.upper; |
| 668 | } |
| 669 | |
| 670 | switch (node.type) { |
| 671 | case 'Program': |
| 672 | case 'FunctionDeclaration': |
| 673 | case 'ComponentDeclaration': |
| 674 | case 'HookDeclaration': |
| 675 | case 'FunctionExpression': |
| 676 | case 'ArrowFunctionExpression': |
| 677 | case 'StaticBlock': { |
| 678 | endCodePath(); |
| 679 | break; |
| 680 | } |
| 681 | |
| 682 | // The `arguments.length >= 1` case is in `preprocess` function. |
| 683 | case 'CallExpression': |
| 684 | if (node.optional === true && node.arguments.length === 0) { |
| 685 | CodePath.getState(analyzer.codePath).makeOptionalRight(); |
| 686 | } |
| 687 | break; |
| 688 | |
| 689 | default: |
| 690 | break; |
| 691 | } |
| 692 | |
| 693 | /* |
| 694 | * Special case: The right side of class field initializer is considered |
| 695 | * to be its own function, so we need to end a code path in this |
| 696 | * case. |
| 697 | * |
| 698 | * We need to check after the other checks in order to close the |
| 699 | * code paths in the correct order for code like this: |
| 700 | * |
| 701 | * |
| 702 | * class Foo { |
| 703 | * a = () => {} |
| 704 | * } |
| 705 | * |
| 706 | * In this case, The ArrowFunctionExpression code path is closed first |
| 707 | * and then we need to close the code path for the PropertyDefinition |
| 708 | * value. |
| 709 | */ |
| 710 | if (isPropertyDefinitionValue(node)) { |
| 711 | endCodePath(); |
| 712 | } |
| 713 | } |
| 714 | |
| 715 | //------------------------------------------------------------------------------ |
| 716 | // Public Interface |
| 717 | //------------------------------------------------------------------------------ |
| 718 | |
| 719 | /** |
| 720 | * The class to analyze code paths. |
| 721 | * This class implements the EventGenerator interface. |
| 722 | */ |
| 723 | class CodePathAnalyzer { |
| 724 | /** |
| 725 | * @param {EventGenerator} eventGenerator An event generator to wrap. |
| 726 | */ |
| 727 | constructor(emitters) { |
| 728 | this.emitter = { |
| 729 | emit(event, ...args) { |
| 730 | emitters[event]?.(...args); |
| 731 | }, |
| 732 | }; |
| 733 | this.codePath = null; |
| 734 | this.idGenerator = new IdGenerator('s'); |
| 735 | this.currentNode = null; |
| 736 | this.onLooped = this.onLooped.bind(this); |
| 737 | } |
| 738 | |
| 739 | /** |
| 740 | * Does the process to enter a given AST node. |
| 741 | * This updates state of analysis and calls `enterNode` of the wrapped. |
| 742 | * @param {ASTNode} node A node which is entering. |
| 743 | * @returns {void} |
| 744 | */ |
| 745 | enterNode(node) { |
| 746 | this.currentNode = node; |
| 747 | |
| 748 | // Updates the code path due to node's position in its parent node. |
| 749 | if (node.parent) { |
| 750 | preprocess(this, node); |
| 751 | } |
| 752 | |
| 753 | /* |
| 754 | * Updates the code path. |
| 755 | * And emits onCodePathStart/onCodePathSegmentStart events. |
| 756 | */ |
| 757 | processCodePathToEnter(this, node); |
| 758 | |
| 759 | this.currentNode = null; |
| 760 | } |
| 761 | |
| 762 | /** |
| 763 | * Does the process to leave a given AST node. |
| 764 | * This updates state of analysis and calls `leaveNode` of the wrapped. |
| 765 | * @param {ASTNode} node A node which is leaving. |
| 766 | * @returns {void} |
| 767 | */ |
| 768 | leaveNode(node) { |
| 769 | this.currentNode = node; |
| 770 | |
| 771 | /* |
| 772 | * Updates the code path. |
| 773 | * And emits onCodePathStart/onCodePathSegmentStart events. |
| 774 | */ |
| 775 | processCodePathToExit(this, node); |
| 776 | |
| 777 | // Emits the last onCodePathStart/onCodePathSegmentStart events. |
| 778 | postprocess(this, node); |
| 779 | |
| 780 | this.currentNode = null; |
| 781 | } |
| 782 | |
| 783 | /** |
| 784 | * This is called on a code path looped. |
| 785 | * Then this raises a looped event. |
| 786 | * @param {CodePathSegment} fromSegment A segment of prev. |
| 787 | * @param {CodePathSegment} toSegment A segment of next. |
| 788 | * @returns {void} |
| 789 | */ |
| 790 | onLooped(fromSegment, toSegment) { |
| 791 | if (fromSegment.reachable && toSegment.reachable) { |
| 792 | this.emitter.emit( |
| 793 | 'onCodePathSegmentLoop', |
| 794 | fromSegment, |
| 795 | toSegment, |
| 796 | this.currentNode, |
| 797 | ); |
| 798 | } |
| 799 | } |
| 800 | } |
| 801 | |
| 802 | module.exports = CodePathAnalyzer; |