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