/** * 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. */ "use strict"; var _interopRequireWildcard = require("@babel/runtime/helpers/interopRequireWildcard"); var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault"); var _assert = _interopRequireDefault(require("assert")); var _hoist = require("./hoist"); var _emit = require("./emit"); var _replaceShorthandObjectMethod = _interopRequireDefault(require("./replaceShorthandObjectMethod")); var util = _interopRequireWildcard(require("./util")); exports.getVisitor = function (_ref) { var t = _ref.types; return { Method: function Method(path, state) { var node = path.node; if (!shouldRegenerate(node, state)) return; var container = t.functionExpression(null, [], t.cloneNode(node.body, false), node.generator, node.async); path.get("body").set("body", [t.returnStatement(t.callExpression(container, []))]); // Regardless of whether or not the wrapped function is a an async method // or generator the outer function should not be node.async = false; node.generator = false; // Unwrap the wrapper IIFE's environment so super and this and such still work. path.get("body.body.0.argument.callee").unwrapFunctionEnvironment(); }, Function: { exit: util.wrapWithTypes(t, function (path, state) { var node = path.node; if (!shouldRegenerate(node, state)) return; // if this is an ObjectMethod, we need to convert it to an ObjectProperty path = (0, _replaceShorthandObjectMethod["default"])(path); node = path.node; var contextId = path.scope.generateUidIdentifier("context"); var argsId = path.scope.generateUidIdentifier("args"); path.ensureBlock(); var bodyBlockPath = path.get("body"); if (node.async) { bodyBlockPath.traverse(awaitVisitor); } bodyBlockPath.traverse(functionSentVisitor, { context: contextId }); var outerBody = []; var innerBody = []; bodyBlockPath.get("body").forEach(function (childPath) { var node = childPath.node; if (t.isExpressionStatement(node) && t.isStringLiteral(node.expression)) { // Babylon represents directives like "use strict" as elements // of a bodyBlockPath.node.directives array, but they could just // as easily be represented (by other parsers) as traditional // string-literal-valued expression statements, so we need to // handle that here. (#248) outerBody.push(node); } else if (node && node._blockHoist != null) { outerBody.push(node); } else { innerBody.push(node); } }); if (outerBody.length > 0) { // Only replace the inner body if we actually hoisted any statements // to the outer body. bodyBlockPath.node.body = innerBody; } var outerFnExpr = getOuterFnExpr(path); // Note that getOuterFnExpr has the side-effect of ensuring that the // function has a name (so node.id will always be an Identifier), even // if a temporary name has to be synthesized. t.assertIdentifier(node.id); var innerFnId = t.identifier(node.id.name + "$"); // Turn all declarations into vars, and replace the original // declarations with equivalent assignment expressions. var vars = (0, _hoist.hoist)(path); var context = { usesThis: false, usesArguments: false, getArgsId: function getArgsId() { return t.clone(argsId); } }; path.traverse(argumentsThisVisitor, context); if (context.usesArguments) { vars = vars || t.variableDeclaration("var", []); vars.declarations.push(t.variableDeclarator(t.clone(argsId), t.identifier("arguments"))); } var emitter = new _emit.Emitter(contextId); emitter.explode(path.get("body")); if (vars && vars.declarations.length > 0) { outerBody.push(vars); } var wrapArgs = [emitter.getContextFunction(innerFnId)]; var tryLocsList = emitter.getTryLocsList(); if (node.generator) { wrapArgs.push(outerFnExpr); } else if (context.usesThis || tryLocsList || node.async) { // Async functions that are not generators don't care about the // outer function because they don't need it to be marked and don't // inherit from its .prototype. wrapArgs.push(t.nullLiteral()); } if (context.usesThis) { wrapArgs.push(t.thisExpression()); } else if (tryLocsList || node.async) { wrapArgs.push(t.nullLiteral()); } if (tryLocsList) { wrapArgs.push(tryLocsList); } else if (node.async) { wrapArgs.push(t.nullLiteral()); } if (node.async) { // Rename any locally declared "Promise" variable, // to use the global one. var currentScope = path.scope; do { if (currentScope.hasOwnBinding("Promise")) currentScope.rename("Promise"); } while (currentScope = currentScope.parent); wrapArgs.push(t.identifier("Promise")); } var wrapCall = t.callExpression(util.runtimeProperty(node.async ? "async" : "wrap"), wrapArgs); outerBody.push(t.returnStatement(wrapCall)); node.body = t.blockStatement(outerBody); // We injected a few new variable declarations (for every hoisted var), // so we need to add them to the scope. path.get("body.body").forEach(function (p) { return p.scope.registerDeclaration(p); }); var oldDirectives = bodyBlockPath.node.directives; if (oldDirectives) { // Babylon represents directives like "use strict" as elements of // a bodyBlockPath.node.directives array. (#248) node.body.directives = oldDirectives; } var wasGeneratorFunction = node.generator; if (wasGeneratorFunction) { node.generator = false; } if (node.async) { node.async = false; } if (wasGeneratorFunction && t.isExpression(node)) { util.replaceWithOrRemove(path, t.callExpression(util.runtimeProperty("mark"), [node])); path.addComment("leading", "#__PURE__"); } var insertedLocs = emitter.getInsertedLocs(); path.traverse({ NumericLiteral: function NumericLiteral(path) { if (!insertedLocs.has(path.node)) { return; } path.replaceWith(t.numericLiteral(path.node.value)); } }); // Generators are processed in 'exit' handlers so that regenerator only has to run on // an ES5 AST, but that means traversal will not pick up newly inserted references // to things like 'regeneratorRuntime'. To avoid this, we explicitly requeue. path.requeue(); }) } }; }; // Check if a node should be transformed by regenerator function shouldRegenerate(node, state) { if (node.generator) { if (node.async) { // Async generator return state.opts.asyncGenerators !== false; } else { // Plain generator return state.opts.generators !== false; } } else if (node.async) { // Async function return state.opts.async !== false; } else { // Not a generator or async function. return false; } } // Given a NodePath for a Function, return an Expression node that can be // used to refer reliably to the function object from inside the function. // This expression is essentially a replacement for arguments.callee, with // the key advantage that it works in strict mode. function getOuterFnExpr(funPath) { var t = util.getTypes(); var node = funPath.node; t.assertFunction(node); if (!node.id) { // Default-exported function declarations, and function expressions may not // have a name to reference, so we explicitly add one. node.id = funPath.scope.parent.generateUidIdentifier("callee"); } if (node.generator && // Non-generator functions don't need to be marked. t.isFunctionDeclaration(node)) { // Return the identifier returned by runtime.mark(<node.id>). return getMarkedFunctionId(funPath); } return t.clone(node.id); } var markInfo = new WeakMap(); function getMarkInfo(node) { if (!markInfo.has(node)) { markInfo.set(node, {}); } return markInfo.get(node); } function getMarkedFunctionId(funPath) { var t = util.getTypes(); var node = funPath.node; t.assertIdentifier(node.id); var blockPath = funPath.findParent(function (path) { return path.isProgram() || path.isBlockStatement(); }); if (!blockPath) { return node.id; } var block = blockPath.node; _assert["default"].ok(Array.isArray(block.body)); var info = getMarkInfo(block); if (!info.decl) { info.decl = t.variableDeclaration("var", []); blockPath.unshiftContainer("body", info.decl); info.declPath = blockPath.get("body.0"); } _assert["default"].strictEqual(info.declPath.node, info.decl); // Get a new unique identifier for our marked variable. var markedId = blockPath.scope.generateUidIdentifier("marked"); var markCallExp = t.callExpression(util.runtimeProperty("mark"), [t.clone(node.id)]); var index = info.decl.declarations.push(t.variableDeclarator(markedId, markCallExp)) - 1; var markCallExpPath = info.declPath.get("declarations." + index + ".init"); _assert["default"].strictEqual(markCallExpPath.node, markCallExp); markCallExpPath.addComment("leading", "#__PURE__"); return t.clone(markedId); } var argumentsThisVisitor = { "FunctionExpression|FunctionDeclaration|Method": function FunctionExpressionFunctionDeclarationMethod(path) { path.skip(); }, Identifier: function Identifier(path, state) { if (path.node.name === "arguments" && util.isReference(path)) { util.replaceWithOrRemove(path, state.getArgsId()); state.usesArguments = true; } }, ThisExpression: function ThisExpression(path, state) { state.usesThis = true; } }; var functionSentVisitor = { MetaProperty: function MetaProperty(path) { var node = path.node; if (node.meta.name === "function" && node.property.name === "sent") { var t = util.getTypes(); util.replaceWithOrRemove(path, t.memberExpression(t.clone(this.context), t.identifier("_sent"))); } } }; var awaitVisitor = { Function: function Function(path) { path.skip(); // Don't descend into nested function scopes. }, AwaitExpression: function AwaitExpression(path) { var t = util.getTypes(); // Convert await expressions to yield expressions. var argument = path.node.argument; // Transforming `await x` to `yield regeneratorRuntime.awrap(x)` // causes the argument to be wrapped in such a way that the runtime // can distinguish between awaited and merely yielded values. util.replaceWithOrRemove(path, t.yieldExpression(t.callExpression(util.runtimeProperty("awrap"), [argument]), false)); } };