64 lines
2.3 KiB
JavaScript
64 lines
2.3 KiB
JavaScript
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/**
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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* Copyright (c) 2017, Amjad Masad
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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'use strict';
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// Based on https://repl.it/site/blog/infinite-loops.
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// This should be reasonable for all loops in the source.
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// Note that if the numbers are too large, the tests will take too long to fail
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// for this to be useful (each individual test case might hit an infinite loop).
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const MAX_SOURCE_ITERATIONS = 5000;
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// Code in tests themselves is permitted to run longer.
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// For example, in the fuzz tester.
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const MAX_TEST_ITERATIONS = 5000;
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module.exports = ({
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types: t,
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template
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}) => {
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// We set a global so that we can later fail the test
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// even if the error ends up being caught by the code.
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const buildGuard = `
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if (%%iterator%%++ > %%maxIterations%%) {
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global.infiniteLoopError = new RangeError(
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'Potential infinite loop: exceeded ' +
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%%maxIterations%% +
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' iterations.'
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);
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throw global.infiniteLoopError;
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}
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` |> template(%);
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return {
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visitor: {
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'WhileStatement|ForStatement|DoWhileStatement': (path, file) => {
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const filename = file.file.opts.filename;
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const maxIterations = t.logicalExpression('||', 'global' |> t.identifier(%) |> t.memberExpression(%, '__MAX_ITERATIONS__' |> t.identifier(%)), (('__tests__' |> filename.indexOf(%)) === -1 ? MAX_SOURCE_ITERATIONS : MAX_TEST_ITERATIONS) |> t.numericLiteral(%));
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// An iterator that is incremented with each iteration
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const iterator = 'loopIt' |> path.scope.parent.generateUidIdentifier(%);
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const iteratorInit = 0 |> t.numericLiteral(%);
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// If statement and throw error if it matches our criteria
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({
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id: iterator,
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init: iteratorInit
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}) |> path.scope.parent.push(%);
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const guard = {
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iterator,
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maxIterations
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} |> buildGuard(%);
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// No block statement e.g. `while (1) 1;`
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if (!('body' |> path.get(%)).isBlockStatement()) {
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const statement = ('body' |> path.get(%)).node;
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[guard, statement] |> t.blockStatement(%) |> ('body' |> path.get(%)).replaceWith(%);
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} else {
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'body' |> ('body' |> path.get(%)).unshiftContainer(%, guard);
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}
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}
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}
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};
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};
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