[6a3a178] | 1 | /**
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| 2 | * Copyright (c) 2014-present, Facebook, Inc.
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| 3 | *
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| 4 | * This source code is licensed under the MIT license found in the
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| 5 | * LICENSE file in the root directory of this source tree.
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| 6 | */
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| 7 |
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| 8 | "use strict";
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| 9 |
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| 10 | import assert from "assert";
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| 11 | import { hoist } from "./hoist";
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| 12 | import { Emitter } from "./emit";
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| 13 | import replaceShorthandObjectMethod from "./replaceShorthandObjectMethod";
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| 14 | import * as util from "./util";
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| 15 |
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| 16 | exports.getVisitor = ({ types: t }) => ({
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| 17 | Method(path, state) {
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| 18 | let node = path.node;
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| 19 |
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| 20 | if (!shouldRegenerate(node, state)) return;
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| 21 |
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| 22 | const container = t.functionExpression(
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| 23 | null,
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| 24 | [],
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| 25 | t.cloneNode(node.body, false),
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| 26 | node.generator,
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| 27 | node.async,
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| 28 | );
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| 29 |
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| 30 | path.get("body").set("body", [
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| 31 | t.returnStatement(
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| 32 | t.callExpression(container, []),
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| 33 | ),
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| 34 | ]);
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| 35 |
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| 36 | // Regardless of whether or not the wrapped function is a an async method
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| 37 | // or generator the outer function should not be
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| 38 | node.async = false;
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| 39 | node.generator = false;
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| 40 |
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| 41 | // Unwrap the wrapper IIFE's environment so super and this and such still work.
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| 42 | path
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| 43 | .get("body.body.0.argument.callee")
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| 44 | .unwrapFunctionEnvironment();
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| 45 | },
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| 46 | Function: {
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| 47 | exit: util.wrapWithTypes(t, function(path, state) {
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| 48 | let node = path.node;
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| 49 |
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| 50 | if (!shouldRegenerate(node, state)) return;
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| 51 |
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| 52 | // if this is an ObjectMethod, we need to convert it to an ObjectProperty
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| 53 | path = replaceShorthandObjectMethod(path);
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| 54 | node = path.node;
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| 55 |
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| 56 | let contextId = path.scope.generateUidIdentifier("context");
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| 57 | let argsId = path.scope.generateUidIdentifier("args");
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| 58 |
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| 59 | path.ensureBlock();
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| 60 | let bodyBlockPath = path.get("body");
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| 61 |
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| 62 | if (node.async) {
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| 63 | bodyBlockPath.traverse(awaitVisitor);
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| 64 | }
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| 65 |
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| 66 | bodyBlockPath.traverse(functionSentVisitor, {
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| 67 | context: contextId
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| 68 | });
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| 69 |
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| 70 | let outerBody = [];
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| 71 | let innerBody = [];
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| 72 |
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| 73 | bodyBlockPath.get("body").forEach(function(childPath) {
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| 74 | let node = childPath.node;
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| 75 | if (t.isExpressionStatement(node) &&
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| 76 | t.isStringLiteral(node.expression)) {
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| 77 | // Babylon represents directives like "use strict" as elements
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| 78 | // of a bodyBlockPath.node.directives array, but they could just
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| 79 | // as easily be represented (by other parsers) as traditional
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| 80 | // string-literal-valued expression statements, so we need to
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| 81 | // handle that here. (#248)
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| 82 | outerBody.push(node);
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| 83 | } else if (node && node._blockHoist != null) {
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| 84 | outerBody.push(node);
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| 85 | } else {
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| 86 | innerBody.push(node);
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| 87 | }
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| 88 | });
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| 89 |
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| 90 | if (outerBody.length > 0) {
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| 91 | // Only replace the inner body if we actually hoisted any statements
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| 92 | // to the outer body.
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| 93 | bodyBlockPath.node.body = innerBody;
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| 94 | }
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| 95 |
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| 96 | let outerFnExpr = getOuterFnExpr(path);
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| 97 | // Note that getOuterFnExpr has the side-effect of ensuring that the
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| 98 | // function has a name (so node.id will always be an Identifier), even
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| 99 | // if a temporary name has to be synthesized.
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| 100 | t.assertIdentifier(node.id);
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| 101 | let innerFnId = t.identifier(node.id.name + "$");
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| 102 |
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| 103 | // Turn all declarations into vars, and replace the original
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| 104 | // declarations with equivalent assignment expressions.
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| 105 | let vars = hoist(path);
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| 106 |
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| 107 | let context = {
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| 108 | usesThis: false,
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| 109 | usesArguments: false,
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| 110 | getArgsId: () => t.clone(argsId),
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| 111 | };
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| 112 | path.traverse(argumentsThisVisitor, context);
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| 113 |
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| 114 | if (context.usesArguments) {
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| 115 | vars = vars || t.variableDeclaration("var", []);
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| 116 | vars.declarations.push(t.variableDeclarator(
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| 117 | t.clone(argsId),
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| 118 | t.identifier("arguments"),
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| 119 | ));
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| 120 | }
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| 121 |
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| 122 | let emitter = new Emitter(contextId);
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| 123 | emitter.explode(path.get("body"));
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| 124 |
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| 125 | if (vars && vars.declarations.length > 0) {
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| 126 | outerBody.push(vars);
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| 127 | }
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| 128 |
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| 129 | let wrapArgs = [emitter.getContextFunction(innerFnId)];
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| 130 | let tryLocsList = emitter.getTryLocsList();
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| 131 |
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| 132 | if (node.generator) {
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| 133 | wrapArgs.push(outerFnExpr);
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| 134 | } else if (context.usesThis || tryLocsList || node.async) {
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| 135 | // Async functions that are not generators don't care about the
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| 136 | // outer function because they don't need it to be marked and don't
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| 137 | // inherit from its .prototype.
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| 138 | wrapArgs.push(t.nullLiteral());
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| 139 | }
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| 140 | if (context.usesThis) {
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| 141 | wrapArgs.push(t.thisExpression());
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| 142 | } else if (tryLocsList || node.async) {
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| 143 | wrapArgs.push(t.nullLiteral());
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| 144 | }
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| 145 | if (tryLocsList) {
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| 146 | wrapArgs.push(tryLocsList);
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| 147 | } else if (node.async) {
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| 148 | wrapArgs.push(t.nullLiteral());
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| 149 | }
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| 150 |
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| 151 | if (node.async) {
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| 152 | // Rename any locally declared "Promise" variable,
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| 153 | // to use the global one.
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| 154 | let currentScope = path.scope;
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| 155 | do {
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| 156 | if (currentScope.hasOwnBinding("Promise")) currentScope.rename("Promise");
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| 157 | } while (currentScope = currentScope.parent);
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| 158 |
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| 159 | wrapArgs.push(t.identifier("Promise"));
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| 160 | }
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| 161 |
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| 162 | let wrapCall = t.callExpression(
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| 163 | util.runtimeProperty(node.async ? "async" : "wrap"),
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| 164 | wrapArgs
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| 165 | );
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| 166 |
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| 167 | outerBody.push(t.returnStatement(wrapCall));
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| 168 | node.body = t.blockStatement(outerBody);
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| 169 | // We injected a few new variable declarations (for every hoisted var),
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| 170 | // so we need to add them to the scope.
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| 171 | path.get("body.body").forEach(p => p.scope.registerDeclaration(p));
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| 172 |
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| 173 | const oldDirectives = bodyBlockPath.node.directives;
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| 174 | if (oldDirectives) {
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| 175 | // Babylon represents directives like "use strict" as elements of
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| 176 | // a bodyBlockPath.node.directives array. (#248)
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| 177 | node.body.directives = oldDirectives;
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| 178 | }
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| 179 |
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| 180 | let wasGeneratorFunction = node.generator;
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| 181 | if (wasGeneratorFunction) {
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| 182 | node.generator = false;
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| 183 | }
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| 184 |
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| 185 | if (node.async) {
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| 186 | node.async = false;
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| 187 | }
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| 188 |
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| 189 | if (wasGeneratorFunction && t.isExpression(node)) {
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| 190 | util.replaceWithOrRemove(path, t.callExpression(util.runtimeProperty("mark"), [node]))
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| 191 | path.addComment("leading", "#__PURE__");
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| 192 | }
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| 193 |
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| 194 | const insertedLocs = emitter.getInsertedLocs();
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| 195 |
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| 196 | path.traverse({
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| 197 | NumericLiteral(path) {
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| 198 | if (!insertedLocs.has(path.node)) {
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| 199 | return;
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| 200 | }
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| 201 |
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| 202 | path.replaceWith(t.numericLiteral(path.node.value));
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| 203 | },
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| 204 | })
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| 205 |
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| 206 | // Generators are processed in 'exit' handlers so that regenerator only has to run on
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| 207 | // an ES5 AST, but that means traversal will not pick up newly inserted references
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| 208 | // to things like 'regeneratorRuntime'. To avoid this, we explicitly requeue.
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| 209 | path.requeue();
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| 210 | })
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| 211 | }
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| 212 | });
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| 213 |
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| 214 | // Check if a node should be transformed by regenerator
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| 215 | function shouldRegenerate(node, state) {
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| 216 | if (node.generator) {
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| 217 | if (node.async) {
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| 218 | // Async generator
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| 219 | return state.opts.asyncGenerators !== false;
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| 220 | } else {
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| 221 | // Plain generator
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| 222 | return state.opts.generators !== false;
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| 223 | }
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| 224 | } else if (node.async) {
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| 225 | // Async function
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| 226 | return state.opts.async !== false;
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| 227 | } else {
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| 228 | // Not a generator or async function.
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| 229 | return false;
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| 230 | }
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| 231 | }
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| 232 |
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| 233 | // Given a NodePath for a Function, return an Expression node that can be
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| 234 | // used to refer reliably to the function object from inside the function.
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| 235 | // This expression is essentially a replacement for arguments.callee, with
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| 236 | // the key advantage that it works in strict mode.
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| 237 | function getOuterFnExpr(funPath) {
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| 238 | const t = util.getTypes();
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| 239 | let node = funPath.node;
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| 240 | t.assertFunction(node);
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| 241 |
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| 242 | if (!node.id) {
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| 243 | // Default-exported function declarations, and function expressions may not
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| 244 | // have a name to reference, so we explicitly add one.
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| 245 | node.id = funPath.scope.parent.generateUidIdentifier("callee");
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| 246 | }
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| 247 |
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| 248 | if (node.generator && // Non-generator functions don't need to be marked.
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| 249 | t.isFunctionDeclaration(node)) {
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| 250 | // Return the identifier returned by runtime.mark(<node.id>).
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| 251 | return getMarkedFunctionId(funPath);
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| 252 | }
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| 253 |
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| 254 | return t.clone(node.id);
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| 255 | }
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| 256 |
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| 257 | const markInfo = new WeakMap();
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| 258 |
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| 259 | function getMarkInfo(node) {
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| 260 | if (!markInfo.has(node)) {
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| 261 | markInfo.set(node, {});
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| 262 | }
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| 263 | return markInfo.get(node);
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| 264 | }
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| 265 |
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| 266 | function getMarkedFunctionId(funPath) {
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| 267 | const t = util.getTypes();
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| 268 | const node = funPath.node;
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| 269 | t.assertIdentifier(node.id);
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| 270 |
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| 271 | const blockPath = funPath.findParent(function (path) {
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| 272 | return path.isProgram() || path.isBlockStatement();
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| 273 | });
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| 274 |
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| 275 | if (!blockPath) {
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| 276 | return node.id;
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| 277 | }
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| 278 |
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| 279 | const block = blockPath.node;
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| 280 | assert.ok(Array.isArray(block.body));
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| 281 |
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| 282 | const info = getMarkInfo(block);
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| 283 | if (!info.decl) {
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| 284 | info.decl = t.variableDeclaration("var", []);
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| 285 | blockPath.unshiftContainer("body", info.decl);
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| 286 | info.declPath = blockPath.get("body.0");
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| 287 | }
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| 288 |
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| 289 | assert.strictEqual(info.declPath.node, info.decl);
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| 290 |
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| 291 | // Get a new unique identifier for our marked variable.
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| 292 | const markedId = blockPath.scope.generateUidIdentifier("marked");
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| 293 | const markCallExp = t.callExpression(
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| 294 | util.runtimeProperty("mark"),
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| 295 | [t.clone(node.id)]
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| 296 | );
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| 297 |
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| 298 | const index = info.decl.declarations.push(
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| 299 | t.variableDeclarator(markedId, markCallExp)
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| 300 | ) - 1;
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| 301 |
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| 302 | const markCallExpPath =
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| 303 | info.declPath.get("declarations." + index + ".init");
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| 304 |
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| 305 | assert.strictEqual(markCallExpPath.node, markCallExp);
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| 306 |
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| 307 | markCallExpPath.addComment("leading", "#__PURE__");
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| 308 |
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| 309 | return t.clone(markedId);
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| 310 | }
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| 311 |
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| 312 | let argumentsThisVisitor = {
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| 313 | "FunctionExpression|FunctionDeclaration|Method": function(path) {
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| 314 | path.skip();
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| 315 | },
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| 316 |
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| 317 | Identifier: function(path, state) {
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| 318 | if (path.node.name === "arguments" && util.isReference(path)) {
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| 319 | util.replaceWithOrRemove(path, state.getArgsId());
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| 320 | state.usesArguments = true;
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| 321 | }
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| 322 | },
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| 323 |
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| 324 | ThisExpression: function(path, state) {
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| 325 | state.usesThis = true;
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| 326 | }
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| 327 | };
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| 328 |
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| 329 | let functionSentVisitor = {
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| 330 | MetaProperty(path) {
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| 331 | let { node } = path;
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| 332 |
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| 333 | if (node.meta.name === "function" &&
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| 334 | node.property.name === "sent") {
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| 335 | const t = util.getTypes();
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| 336 | util.replaceWithOrRemove(
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| 337 | path,
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| 338 | t.memberExpression(
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| 339 | t.clone(this.context),
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| 340 | t.identifier("_sent")
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| 341 | )
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| 342 | );
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| 343 | }
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| 344 | }
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| 345 | };
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| 346 |
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| 347 | let awaitVisitor = {
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| 348 | Function: function(path) {
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| 349 | path.skip(); // Don't descend into nested function scopes.
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| 350 | },
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| 351 |
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| 352 | AwaitExpression: function(path) {
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| 353 | const t = util.getTypes();
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| 354 |
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| 355 | // Convert await expressions to yield expressions.
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| 356 | let argument = path.node.argument;
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| 357 |
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| 358 | // Transforming `await x` to `yield regeneratorRuntime.awrap(x)`
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| 359 | // causes the argument to be wrapped in such a way that the runtime
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| 360 | // can distinguish between awaited and merely yielded values.
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| 361 | util.replaceWithOrRemove(path, t.yieldExpression(
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| 362 | t.callExpression(
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| 363 | util.runtimeProperty("awrap"),
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| 364 | [argument]
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| 365 | ),
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| 366 | false
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| 367 | ));
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| 368 | }
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| 369 | };
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