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334 lines
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JavaScript

6 years ago
var NotAsync = {} ;
var asyncExit = /^async[\t ]+(return|throw)/ ;
var asyncFunction = /^async[\t ]+function/ ;
var atomOrPropertyOrLabel = /^\s*[():;]/ ;
var removeComments = /([^\n])\/\*(\*(?!\/)|[^\n*])*\*\/([^\n])/g ;
var matchAsyncGet = /\s*(get|set)\s*\(/ ;
function hasLineTerminatorBeforeNext(st, since) {
return st.lineStart >= since;
}
function test(regex,st,noComment) {
var src = st.input.slice(st.start) ;
if (noComment) {
src = src.replace(removeComments,"$1 $3") ;
}
return regex.test(src);
}
/* Create a new parser derived from the specified parser, so that in the
* event of an error we can back out and try again */
function subParse(parser, pos, extensions,parens) {
var p = new parser.constructor(parser.options, parser.input, pos);
if (extensions)
for (var k in extensions)
p[k] = extensions[k] ;
var src = parser ;
var dest = p ;
['inFunction','inAsyncFunction','inAsync','inGenerator','inModule'].forEach(function(k){
if (k in src)
dest[k] = src[k] ;
}) ;
if (parens)
p.options.preserveParens = true ;
p.nextToken();
return p;
}
//TODO: Implement option noAsyncGetters
function asyncAwaitPlugin (parser,options){
var es7check = function(){} ;
parser.extend("initialContext",function(base){
return function(){
if (this.options.ecmaVersion < 7) {
es7check = function(node) {
parser.raise(node.start,"async/await keywords only available when ecmaVersion>=7") ;
} ;
}
this.reservedWords = new RegExp(this.reservedWords.toString().replace(/await|async/g,"").replace("|/","/").replace("/|","/").replace("||","|")) ;
this.reservedWordsStrict = new RegExp(this.reservedWordsStrict.toString().replace(/await|async/g,"").replace("|/","/").replace("/|","/").replace("||","|")) ;
this.reservedWordsStrictBind = new RegExp(this.reservedWordsStrictBind.toString().replace(/await|async/g,"").replace("|/","/").replace("/|","/").replace("||","|")) ;
this.inAsyncFunction = options.inAsyncFunction ;
if (options.awaitAnywhere && options.inAsyncFunction)
parser.raise(node.start,"The options awaitAnywhere and inAsyncFunction are mutually exclusive") ;
return base.apply(this,arguments);
}
}) ;
parser.extend("shouldParseExportStatement",function(base){
return function(){
if (this.type.label==='name' && this.value==='async' && test(asyncFunction,this)) {
return true ;
}
return base.apply(this,arguments) ;
}
}) ;
parser.extend("parseStatement",function(base){
return function (declaration, topLevel) {
var start = this.start;
var startLoc = this.startLoc;
if (this.type.label==='name') {
if (test(asyncFunction,this,true)) {
var wasAsync = this.inAsyncFunction ;
try {
this.inAsyncFunction = true ;
this.next() ;
var r = this.parseStatement(declaration, topLevel) ;
r.async = true ;
r.start = start;
r.loc && (r.loc.start = startLoc);
r.range && (r.range[0] = start);
return r ;
} finally {
this.inAsyncFunction = wasAsync ;
}
} else if ((typeof options==="object" && options.asyncExits) && test(asyncExit,this)) {
// NON-STANDARD EXTENSION iff. options.asyncExits is set, the
// extensions 'async return <expr>?' and 'async throw <expr>?'
// are enabled. In each case they are the standard ESTree nodes
// with the flag 'async:true'
this.next() ;
var r = this.parseStatement(declaration, topLevel) ;
r.async = true ;
r.start = start;
r.loc && (r.loc.start = startLoc);
r.range && (r.range[0] = start);
return r ;
}
}
return base.apply(this,arguments);
}
}) ;
parser.extend("parseIdent",function(base){
return function(liberal){
var id = base.apply(this,arguments);
if (this.inAsyncFunction && id.name==='await') {
if (arguments.length===0) {
this.raise(id.start,"'await' is reserved within async functions") ;
}
}
return id ;
}
}) ;
parser.extend("parseExprAtom",function(base){
return function(refShorthandDefaultPos){
var start = this.start ;
var startLoc = this.startLoc;
var rhs,r = base.apply(this,arguments);
if (r.type==='Identifier') {
if (r.name==='async' && !hasLineTerminatorBeforeNext(this, r.end)) {
// Is this really an async function?
var isAsync = this.inAsyncFunction ;
try {
this.inAsyncFunction = true ;
var pp = this ;
var inBody = false ;
var parseHooks = {
parseFunctionBody:function(node,isArrowFunction){
try {
var wasInBody = inBody ;
inBody = true ;
return pp.parseFunctionBody.apply(this,arguments) ;
} finally {
inBody = wasInBody ;
}
},
raise:function(){
try {
return pp.raise.apply(this,arguments) ;
} catch(ex) {
throw inBody?ex:NotAsync ;
}
}
} ;
rhs = subParse(this,this.start,parseHooks,true).parseExpression() ;
if (rhs.type==='SequenceExpression')
rhs = rhs.expressions[0] ;
if (rhs.type === 'CallExpression')
rhs = rhs.callee ;
if (rhs.type==='FunctionExpression' || rhs.type==='FunctionDeclaration' || rhs.type==='ArrowFunctionExpression') {
// Because we don't know if the top level parser supprts preserveParens, we have to re-parse
// without it set
rhs = subParse(this,this.start,parseHooks).parseExpression() ;
if (rhs.type==='SequenceExpression')
rhs = rhs.expressions[0] ;
if (rhs.type === 'CallExpression')
rhs = rhs.callee ;
rhs.async = true ;
rhs.start = start;
rhs.loc && (rhs.loc.start = startLoc);
rhs.range && (rhs.range[0] = start);
this.pos = rhs.end;
this.end = rhs.end ;
this.endLoc = rhs.endLoc ;
this.next();
es7check(rhs) ;
return rhs ;
}
} catch (ex) {
if (ex!==NotAsync)
throw ex ;
}
finally {
this.inAsyncFunction = isAsync ;
}
}
else if (r.name==='await') {
var n = this.startNodeAt(r.start, r.loc && r.loc.start);
if (this.inAsyncFunction) {
rhs = this.parseExprSubscripts() ;
n.operator = 'await' ;
n.argument = rhs ;
n = this.finishNodeAt(n,'AwaitExpression', rhs.end, rhs.loc && rhs.loc.end) ;
es7check(n) ;
return n ;
}
// NON-STANDARD EXTENSION iff. options.awaitAnywhere is true,
// an 'AwaitExpression' is allowed anywhere the token 'await'
// could not be an identifier with the name 'await'.
// Look-ahead to see if this is really a property or label called async or await
if (this.input.slice(r.end).match(atomOrPropertyOrLabel)) {
if (!options.awaitAnywhere && this.options.sourceType === 'module')
return this.raise(r.start,"'await' is reserved within modules") ;
return r ; // This is a valid property name or label
}
if (typeof options==="object" && options.awaitAnywhere) {
start = this.start ;
rhs = subParse(this,start-4).parseExprSubscripts() ;
if (rhs.end<=start) {
rhs = subParse(this,start).parseExprSubscripts() ;
n.operator = 'await' ;
n.argument = rhs ;
n = this.finishNodeAt(n,'AwaitExpression', rhs.end, rhs.loc && rhs.loc.end) ;
this.pos = rhs.end;
this.end = rhs.end ;
this.endLoc = rhs.endLoc ;
this.next();
es7check(n) ;
return n ;
}
}
if (!options.awaitAnywhere && this.options.sourceType === 'module')
return this.raise(r.start,"'await' is reserved within modules") ;
}
}
return r ;
}
}) ;
parser.extend('finishNodeAt',function(base){
return function(node,type,pos,loc) {
if (node.__asyncValue) {
delete node.__asyncValue ;
node.value.async = true ;
}
return base.apply(this,arguments) ;
}
}) ;
parser.extend('finishNode',function(base){
return function(node,type) {
if (node.__asyncValue) {
delete node.__asyncValue ;
node.value.async = true ;
}
return base.apply(this,arguments) ;
}
}) ;
var allowedPropSpecifiers = {
get:true,
set:true,
async:true
};
parser.extend("parsePropertyName",function(base){
return function (prop) {
var prevName = prop.key && prop.key.name ;
var key = base.apply(this,arguments) ;
if (key.type === "Identifier" && (key.name === "async") && !hasLineTerminatorBeforeNext(this, key.end)) {
// Look-ahead to see if this is really a property or label called async or await
if (!this.input.slice(key.end).match(atomOrPropertyOrLabel)){
// Cheese - eliminate the cases 'async get(){}' and async set(){}'
if (matchAsyncGet.test(this.input.slice(key.end))) {
key = base.apply(this,arguments) ;
prop.__asyncValue = true ;
} else {
es7check(prop) ;
if (prop.kind === 'set')
this.raise(key.start,"'set <member>(value)' cannot be be async") ;
key = base.apply(this,arguments) ;
if (key.type==='Identifier') {
if (key.name==='set')
this.raise(key.start,"'set <member>(value)' cannot be be async") ;
}
prop.__asyncValue = true ;
}
}
}
return key;
};
}) ;
parser.extend("parseClassMethod",function(base){
return function (classBody, method, isGenerator) {
var wasAsync ;
if (method.__asyncValue) {
if (method.kind==='constructor')
this.raise(method.start,"class constructor() cannot be be async") ;
wasAsync = this.inAsyncFunction ;
this.inAsyncFunction = true ;
}
var r = base.apply(this,arguments) ;
this.inAsyncFunction = wasAsync ;
return r ;
}
}) ;
parser.extend("parseMethod",function(base){
return function (isGenerator) {
var wasAsync ;
if (this.__currentProperty && this.__currentProperty.__asyncValue) {
wasAsync = this.inAsyncFunction ;
this.inAsyncFunction = true ;
}
var r = base.apply(this,arguments) ;
this.inAsyncFunction = wasAsync ;
return r ;
}
}) ;
parser.extend("parsePropertyValue",function(base){
return function (prop, isPattern, isGenerator, startPos, startLoc, refDestructuringErrors) {
var prevProp = this.__currentProperty ;
this.__currentProperty = prop ;
var wasAsync ;
if (prop.__asyncValue) {
wasAsync = this.inAsyncFunction ;
this.inAsyncFunction = true ;
}
var r = base.apply(this,arguments) ;
this.inAsyncFunction = wasAsync ;
this.__currentProperty = prevProp ;
return r ;
}
}) ;
}
module.exports = asyncAwaitPlugin ;