'use strict'
const npa = require('npm-package-arg')
const parser = require('postcss-selector-parser')
const semver = require('semver')
const arrayDelimiter = Symbol('arrayDelimiter')
const escapeSlashes = str =>
str.replace(/\//g, '\\/')
const unescapeSlashes = str =>
str.replace(/\\\//g, '/')
const fixupIds = astNode => {
const { name, rawSpec: part } = npa(astNode.value)
const versionParts = [{ astNode, part }]
let currentAstNode = astNode.next()
if (!part) {
return
}
while (currentAstNode) {
versionParts.push({ astNode: currentAstNode, part: String(currentAstNode) })
currentAstNode = currentAstNode.next()
}
let version
let length = versionParts.length
while (!version && length) {
version =
semver.valid(
versionParts.slice(0, length).reduce((res, i) => `${res}${i.part}`, '')
)
length--
}
astNode.value = `${name}@${version}`
for (let i = 1; i <= length; i++) {
versionParts[i].astNode.remove()
}
}
// recursively fixes up any :attr pseudo-class found
const fixupAttr = astNode => {
const properties = []
const matcher = {}
for (const selectorAstNode of astNode.nodes) {
const [firstAstNode] = selectorAstNode.nodes
if (firstAstNode.type === 'tag') {
properties.push(firstAstNode.value)
}
}
const lastSelectorAstNode = astNode.nodes.pop()
const [attributeAstNode] = lastSelectorAstNode.nodes
if (attributeAstNode.value === ':attr') {
const appendParts = fixupAttr(attributeAstNode)
properties.push(arrayDelimiter, ...appendParts.lookupProperties)
matcher.qualifiedAttribute = appendParts.attributeMatcher.qualifiedAttribute
matcher.operator = appendParts.attributeMatcher.operator
matcher.value = appendParts.attributeMatcher.value
// backwards compatibility
matcher.attribute = appendParts.attributeMatcher.attribute
if (appendParts.attributeMatcher.insensitive) {
matcher.insensitive = true
}
} else {
if (attributeAstNode.type !== 'attribute') {
throw Object.assign(
new Error('`:attr` pseudo-class expects an attribute matcher as the last value'),
{ code: 'EQUERYATTR' }
)
}
matcher.qualifiedAttribute = unescapeSlashes(attributeAstNode.qualifiedAttribute)
matcher.operator = attributeAstNode.operator
matcher.value = attributeAstNode.value
// backwards compatibility
matcher.attribute = matcher.qualifiedAttribute
if (attributeAstNode.insensitive) {
matcher.insensitive = true
}
}
astNode.lookupProperties = properties
astNode.attributeMatcher = matcher
astNode.nodes.length = 0
return astNode
}
// fixed up nested pseudo nodes will have their internal selectors moved
// to a new root node that will be referenced by the `nestedNode` property,
// this tweak makes it simpler to reuse `retrieveNodesFromParsedAst` to
// recursively parse and extract results from the internal selectors
const fixupNestedPseudo = astNode => {
// create a new ast root node and relocate any children
// selectors of the current ast node to this new root
const newRootNode = parser.root()
astNode.nestedNode = newRootNode
newRootNode.nodes = [...astNode.nodes]
// clean up the ast by removing the children nodes from the
// current ast node while also cleaning up their `parent` refs
astNode.nodes.length = 0
for (const currAstNode of newRootNode.nodes) {
currAstNode.parent = newRootNode
}
// recursively fixup nodes of any nested selector
transformAst(newRootNode)
}
// :semver(, [selector], [function])
const fixupSemverSpecs = astNode => {
// the first child node contains the version or range, most likely as a tag and a series of
// classes. we combine them into a single string here. this is the only required input.
const children = astNode.nodes.shift().nodes
const value = children.reduce((res, i) => `${res}${String(i)}`, '')
// next, if we have 2 nodes left then the user called us with a total of 3. that means the
// last one tells us what specific semver function the user is requesting, so we pull that out
let semverFunc
if (astNode.nodes.length === 2) {
const funcNode = astNode.nodes.pop().nodes[0]
if (funcNode.type === 'tag') {
semverFunc = funcNode.value
}
}
// now if there's a node left, that node is our selector. since that is the last remaining
// child node, we call fixupAttr on ourselves so that the attribute selectors get parsed
if (astNode.nodes.length === 1) {
fixupAttr(astNode)
} else {
// we weren't provided a selector, so we default to `[version]`. note, there's no default
// operator here. that's because we don't know yet if the user has provided us a version
// or range to assert against
astNode.attributeMatcher = {
insensitive: false,
attribute: 'version',
qualifiedAttribute: 'version',
}
astNode.lookupProperties = []
}
astNode.semverFunc = semverFunc
astNode.semverValue = value
astNode.nodes.length = 0
}
const fixupTypes = astNode => {
const [valueAstNode] = astNode.nodes[0].nodes
const { value } = valueAstNode || {}
astNode.typeValue = value
astNode.nodes.length = 0
}
const fixupPaths = astNode => {
astNode.pathValue = unescapeSlashes(String(astNode.nodes[0]))
astNode.nodes.length = 0
}
// a few of the supported ast nodes need to be tweaked in order to properly be
// interpreted as proper arborist query selectors, namely semver ranges from
// both ids and :semver pseudo-class selectors need to be translated from what
// are usually multiple ast nodes, such as: tag:1, class:.0, class:.0 to a
// single `1.0.0` value, other pseudo-class selectors also get preprocessed in
// order to make it simpler to execute later when traversing each ast node
// using rootNode.walk(), such as :path, :type, etc. transformAst handles all
// these modifications to the parsed ast by doing an extra, initial traversal
// of the parsed ast from the query and modifying the parsed nodes accordingly
const transformAst = selector => {
selector.walk((nextAstNode) => {
if (nextAstNode.type === 'id') {
fixupIds(nextAstNode)
}
switch (nextAstNode.value) {
case ':attr':
return fixupAttr(nextAstNode)
case ':is':
case ':has':
case ':not':
return fixupNestedPseudo(nextAstNode)
case ':path':
return fixupPaths(nextAstNode)
case ':semver':
return fixupSemverSpecs(nextAstNode)
case ':type':
return fixupTypes(nextAstNode)
}
})
}
const queryParser = (query) => {
// if query is an empty string or any falsy
// value, just returns an empty result
if (!query) {
return []
}
return parser(transformAst)
.astSync(escapeSlashes(query), { lossless: false })
}
module.exports = {
parser: queryParser,
arrayDelimiter,
}