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4 years ago
/*
compiles a selector to an executable function
*/
module.exports = compile;
var parse = require("css-what").parse;
var BaseFuncs = require("boolbase");
var sortRules = require("./sort.js");
var procedure = require("./procedure.json");
var Rules = require("./general.js");
var Pseudos = require("./pseudos.js");
var trueFunc = BaseFuncs.trueFunc;
var falseFunc = BaseFuncs.falseFunc;
var filters = Pseudos.filters;
function compile(selector, options, context) {
var next = compileUnsafe(selector, options, context);
return wrap(next, options);
}
function wrap(next, options) {
var adapter = options.adapter;
return function base(elem) {
return adapter.isTag(elem) && next(elem);
};
}
function compileUnsafe(selector, options, context) {
var token = parse(selector, options);
return compileToken(token, options, context);
}
function includesScopePseudo(t) {
return (
t.type === "pseudo" &&
(t.name === "scope" ||
(Array.isArray(t.data) &&
t.data.some(function(data) {
return data.some(includesScopePseudo);
})))
);
}
var DESCENDANT_TOKEN = { type: "descendant" };
var FLEXIBLE_DESCENDANT_TOKEN = { type: "_flexibleDescendant" };
var SCOPE_TOKEN = { type: "pseudo", name: "scope" };
var PLACEHOLDER_ELEMENT = {};
//CSS 4 Spec (Draft): 3.3.1. Absolutizing a Scope-relative Selector
//http://www.w3.org/TR/selectors4/#absolutizing
function absolutize(token, options, context) {
var adapter = options.adapter;
//TODO better check if context is document
var hasContext =
!!context &&
!!context.length &&
context.every(function(e) {
return e === PLACEHOLDER_ELEMENT || !!adapter.getParent(e);
});
token.forEach(function(t) {
if (t.length > 0 && isTraversal(t[0]) && t[0].type !== "descendant") {
//don't return in else branch
} else if (hasContext && !(Array.isArray(t) ? t.some(includesScopePseudo) : includesScopePseudo(t))) {
t.unshift(DESCENDANT_TOKEN);
} else {
return;
}
t.unshift(SCOPE_TOKEN);
});
}
function compileToken(token, options, context) {
token = token.filter(function(t) {
return t.length > 0;
});
token.forEach(sortRules);
var isArrayContext = Array.isArray(context);
context = (options && options.context) || context;
if (context && !isArrayContext) context = [context];
absolutize(token, options, context);
var shouldTestNextSiblings = false;
var query = token
.map(function(rules) {
if (rules[0] && rules[1] && rules[0].name === "scope") {
var ruleType = rules[1].type;
if (isArrayContext && ruleType === "descendant") {
rules[1] = FLEXIBLE_DESCENDANT_TOKEN;
} else if (ruleType === "adjacent" || ruleType === "sibling") {
shouldTestNextSiblings = true;
}
}
return compileRules(rules, options, context);
})
.reduce(reduceRules, falseFunc);
query.shouldTestNextSiblings = shouldTestNextSiblings;
return query;
}
function isTraversal(t) {
return procedure[t.type] < 0;
}
function compileRules(rules, options, context) {
return rules.reduce(function(func, rule) {
if (func === falseFunc) return func;
if (!(rule.type in Rules)) {
throw new Error("Rule type " + rule.type + " is not supported by css-select");
}
return Rules[rule.type](func, rule, options, context);
}, (options && options.rootFunc) || trueFunc);
}
function reduceRules(a, b) {
if (b === falseFunc || a === trueFunc) {
return a;
}
if (a === falseFunc || b === trueFunc) {
return b;
}
return function combine(elem) {
return a(elem) || b(elem);
};
}
function containsTraversal(t) {
return t.some(isTraversal);
}
//:not, :has and :matches have to compile selectors
//doing this in lib/pseudos.js would lead to circular dependencies,
//so we add them here
filters.not = function(next, token, options, context) {
var opts = {
xmlMode: !!(options && options.xmlMode),
strict: !!(options && options.strict),
adapter: options.adapter
};
if (opts.strict) {
if (token.length > 1 || token.some(containsTraversal)) {
throw new Error("complex selectors in :not aren't allowed in strict mode");
}
}
var func = compileToken(token, opts, context);
if (func === falseFunc) return next;
if (func === trueFunc) return falseFunc;
return function not(elem) {
return !func(elem) && next(elem);
};
};
filters.has = function(next, token, options) {
var adapter = options.adapter;
var opts = {
xmlMode: !!(options && options.xmlMode),
strict: !!(options && options.strict),
adapter: adapter
};
//FIXME: Uses an array as a pointer to the current element (side effects)
var context = token.some(containsTraversal) ? [PLACEHOLDER_ELEMENT] : null;
var func = compileToken(token, opts, context);
if (func === falseFunc) return falseFunc;
if (func === trueFunc) {
return function hasChild(elem) {
return adapter.getChildren(elem).some(adapter.isTag) && next(elem);
};
}
func = wrap(func, options);
if (context) {
return function has(elem) {
return next(elem) && ((context[0] = elem), adapter.existsOne(func, adapter.getChildren(elem)));
};
}
return function has(elem) {
return next(elem) && adapter.existsOne(func, adapter.getChildren(elem));
};
};
filters.matches = function(next, token, options, context) {
var opts = {
xmlMode: !!(options && options.xmlMode),
strict: !!(options && options.strict),
rootFunc: next,
adapter: options.adapter
};
return compileToken(token, opts, context);
};
compile.compileToken = compileToken;
compile.compileUnsafe = compileUnsafe;
compile.Pseudos = Pseudos;