99 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			99 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
"use strict";Object.defineProperty(exports, "__esModule", {value: true});
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var _tokenizer = require('./parser/tokenizer');
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var _types = require('./parser/tokenizer/types');
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/**
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 * Traverse the given tokens and modify them if necessary to indicate that some names shadow global
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 * variables.
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 */
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 function identifyShadowedGlobals(
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  tokens,
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  scopes,
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  globalNames,
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) {
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  if (!hasShadowedGlobals(tokens, globalNames)) {
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    return;
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  }
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  markShadowedGlobals(tokens, scopes, globalNames);
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} exports.default = identifyShadowedGlobals;
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/**
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 * We can do a fast up-front check to see if there are any declarations to global names. If not,
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 * then there's no point in computing scope assignments.
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 */
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// Exported for testing.
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 function hasShadowedGlobals(tokens, globalNames) {
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  for (const token of tokens.tokens) {
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    if (
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      token.type === _types.TokenType.name &&
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      !token.isType &&
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      _tokenizer.isNonTopLevelDeclaration.call(void 0, token) &&
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      globalNames.has(tokens.identifierNameForToken(token))
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    ) {
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      return true;
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    }
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  }
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  return false;
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} exports.hasShadowedGlobals = hasShadowedGlobals;
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function markShadowedGlobals(
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  tokens,
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  scopes,
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  globalNames,
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) {
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  const scopeStack = [];
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  let scopeIndex = scopes.length - 1;
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  // Scopes were generated at completion time, so they're sorted by end index, so we can maintain a
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  // good stack by going backwards through them.
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  for (let i = tokens.tokens.length - 1; ; i--) {
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    while (scopeStack.length > 0 && scopeStack[scopeStack.length - 1].startTokenIndex === i + 1) {
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      scopeStack.pop();
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    }
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    while (scopeIndex >= 0 && scopes[scopeIndex].endTokenIndex === i + 1) {
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      scopeStack.push(scopes[scopeIndex]);
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      scopeIndex--;
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    }
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    // Process scopes after the last iteration so we can make sure we pop all of them.
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    if (i < 0) {
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      break;
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    }
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    const token = tokens.tokens[i];
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    const name = tokens.identifierNameForToken(token);
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    if (scopeStack.length > 1 && !token.isType && token.type === _types.TokenType.name && globalNames.has(name)) {
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      if (_tokenizer.isBlockScopedDeclaration.call(void 0, token)) {
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        markShadowedForScope(scopeStack[scopeStack.length - 1], tokens, name);
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      } else if (_tokenizer.isFunctionScopedDeclaration.call(void 0, token)) {
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        let stackIndex = scopeStack.length - 1;
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        while (stackIndex > 0 && !scopeStack[stackIndex].isFunctionScope) {
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          stackIndex--;
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        }
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        if (stackIndex < 0) {
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          throw new Error("Did not find parent function scope.");
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        }
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        markShadowedForScope(scopeStack[stackIndex], tokens, name);
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      }
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    }
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  }
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  if (scopeStack.length > 0) {
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    throw new Error("Expected empty scope stack after processing file.");
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  }
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}
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function markShadowedForScope(scope, tokens, name) {
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  for (let i = scope.startTokenIndex; i < scope.endTokenIndex; i++) {
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    const token = tokens.tokens[i];
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    if (
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      (token.type === _types.TokenType.name || token.type === _types.TokenType.jsxName) &&
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      tokens.identifierNameForToken(token) === name
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    ) {
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      token.shadowsGlobal = true;
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    }
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  }
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}
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