111 lines
2.8 KiB
JavaScript
111 lines
2.8 KiB
JavaScript
|
/**
|
||
|
|
* Copyright (c) 2014-present, Facebook, Inc.
|
||
|
|
*
|
||
|
|
* This source code is licensed under the MIT license found in the
|
||
|
|
* LICENSE file in the root directory of this source tree.
|
||
|
|
*/
|
||
|
|
|
||
|
|
import assert from "assert";
|
||
|
|
import { getTypes } from "./util.js";
|
||
|
|
|
||
|
|
const mMap = new WeakMap();
|
||
|
|
function m(node) {
|
||
|
|
if (!mMap.has(node)) {
|
||
|
|
mMap.set(node, {});
|
||
|
|
}
|
||
|
|
return mMap.get(node);
|
||
|
|
}
|
||
|
|
|
||
|
|
const hasOwn = Object.prototype.hasOwnProperty;
|
||
|
|
|
||
|
|
function makePredicate(propertyName, knownTypes) {
|
||
|
|
function onlyChildren(node) {
|
||
|
|
const t = getTypes();
|
||
|
|
t.assertNode(node);
|
||
|
|
|
||
|
|
// Assume no side effects until we find out otherwise.
|
||
|
|
let result = false;
|
||
|
|
|
||
|
|
function check(child) {
|
||
|
|
if (result) {
|
||
|
|
// Do nothing.
|
||
|
|
} else if (Array.isArray(child)) {
|
||
|
|
child.some(check);
|
||
|
|
} else if (t.isNode(child)) {
|
||
|
|
assert.strictEqual(result, false);
|
||
|
|
result = predicate(child);
|
||
|
|
}
|
||
|
|
return result;
|
||
|
|
}
|
||
|
|
|
||
|
|
let keys = t.VISITOR_KEYS[node.type];
|
||
|
|
if (keys) {
|
||
|
|
for (let i = 0; i < keys.length; i++) {
|
||
|
|
let key = keys[i];
|
||
|
|
let child = node[key];
|
||
|
|
check(child);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return result;
|
||
|
|
}
|
||
|
|
|
||
|
|
function predicate(node) {
|
||
|
|
getTypes().assertNode(node);
|
||
|
|
|
||
|
|
let meta = m(node);
|
||
|
|
if (hasOwn.call(meta, propertyName))
|
||
|
|
return meta[propertyName];
|
||
|
|
|
||
|
|
// Certain types are "opaque," which means they have no side
|
||
|
|
// effects or leaps and we don't care about their subexpressions.
|
||
|
|
if (hasOwn.call(opaqueTypes, node.type))
|
||
|
|
return meta[propertyName] = false;
|
||
|
|
|
||
|
|
if (hasOwn.call(knownTypes, node.type))
|
||
|
|
return meta[propertyName] = true;
|
||
|
|
|
||
|
|
return meta[propertyName] = onlyChildren(node);
|
||
|
|
}
|
||
|
|
|
||
|
|
predicate.onlyChildren = onlyChildren;
|
||
|
|
|
||
|
|
return predicate;
|
||
|
|
}
|
||
|
|
|
||
|
|
let opaqueTypes = {
|
||
|
|
FunctionExpression: true,
|
||
|
|
ArrowFunctionExpression: true
|
||
|
|
};
|
||
|
|
|
||
|
|
// These types potentially have side effects regardless of what side
|
||
|
|
// effects their subexpressions have.
|
||
|
|
let sideEffectTypes = {
|
||
|
|
CallExpression: true, // Anything could happen!
|
||
|
|
ForInStatement: true, // Modifies the key variable.
|
||
|
|
UnaryExpression: true, // Think delete.
|
||
|
|
BinaryExpression: true, // Might invoke .toString() or .valueOf().
|
||
|
|
AssignmentExpression: true, // Side-effecting by definition.
|
||
|
|
UpdateExpression: true, // Updates are essentially assignments.
|
||
|
|
NewExpression: true // Similar to CallExpression.
|
||
|
|
};
|
||
|
|
|
||
|
|
// These types are the direct cause of all leaps in control flow.
|
||
|
|
let leapTypes = {
|
||
|
|
YieldExpression: true,
|
||
|
|
BreakStatement: true,
|
||
|
|
ContinueStatement: true,
|
||
|
|
ReturnStatement: true,
|
||
|
|
ThrowStatement: true
|
||
|
|
};
|
||
|
|
|
||
|
|
// All leap types are also side effect types.
|
||
|
|
for (let type in leapTypes) {
|
||
|
|
if (hasOwn.call(leapTypes, type)) {
|
||
|
|
sideEffectTypes[type] = leapTypes[type];
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
exports.hasSideEffects = makePredicate("hasSideEffects", sideEffectTypes);
|
||
|
|
exports.containsLeap = makePredicate("containsLeap", leapTypes);
|