selector.js

import { jQuery } from "./core.js";
import { nodeName } from "./core/nodeName.js";
import { document as preferredDoc } from "./var/document.js";
import { indexOf } from "./var/indexOf.js";
import { pop } from "./var/pop.js";
import { push } from "./var/push.js";
import { whitespace } from "./var/whitespace.js";
import { rbuggyQSA } from "./selector/rbuggyQSA.js";
import { rtrimCSS } from "./var/rtrimCSS.js";
import { isIE } from "./var/isIE.js";
import { identifier } from "./selector/var/identifier.js";
import { rleadingCombinator } from "./selector/var/rleadingCombinator.js";
import { rdescend } from "./selector/var/rdescend.js";
import { rsibling } from "./selector/var/rsibling.js";
import { matches } from "./selector/var/matches.js";
import { createCache } from "./selector/createCache.js";
import { testContext } from "./selector/testContext.js";
import { filterMatchExpr } from "./selector/filterMatchExpr.js";
import { preFilter } from "./selector/preFilter.js";
import { selectorError } from "./selector/selectorError.js";
import { unescapeSelector } from "./selector/unescapeSelector.js";
import { tokenize } from "./selector/tokenize.js";
import { toSelector } from "./selector/toSelector.js";

// The following utils are attached directly to the jQuery object.
import "./attributes/attr.js"; // jQuery.attr
import "./selector/escapeSelector.js";
import "./selector/uniqueSort.js";

var i,
	outermostContext,

	// Local document vars
	document,
	documentElement,
	documentIsHTML,

	// Instance-specific data
	dirruns = 0,
	done = 0,
	classCache = createCache(),
	compilerCache = createCache(),
	nonnativeSelectorCache = createCache(),

	// Regular expressions

	// Leading and non-escaped trailing whitespace, capturing some non-whitespace characters preceding the latter
	rwhitespace = new RegExp( whitespace + "+", "g" ),

	ridentifier = new RegExp( "^" + identifier + "$" ),

	matchExpr = jQuery.extend( {

		// For use in libraries implementing .is()
		// We use this for POS matching in `select`
		needsContext: new RegExp( "^" + whitespace +
			"*[>+~]|:(even|odd|eq|gt|lt|nth|first|last)(?:\\(" + whitespace +
			"*((?:-\\d)?\\d*)" + whitespace + "*\\)|)(?=[^-]|$)", "i" )
	}, filterMatchExpr ),

	rinputs = /^(?:input|select|textarea|button)$/i,
	rheader = /^h\d$/i,

	// Easily-parseable/retrievable ID or TAG or CLASS selectors
	rquickExpr = /^(?:#([\w-]+)|(\w+)|\.([\w-]+))$/,

	// Used for iframes; see `setDocument`.
	// Support: IE 9 - 11+
	// Removing the function wrapper causes a "Permission Denied"
	// error in IE.
	unloadHandler = function() {
		setDocument();
	},

	inDisabledFieldset = addCombinator(
		function( elem ) {
			return elem.disabled === true && nodeName( elem, "fieldset" );
		},
		{ dir: "parentNode", next: "legend" }
	);

function find( selector, context, results, seed ) {
	var m, i, elem, nid, match, groups, newSelector,
		newContext = context && context.ownerDocument,

		// nodeType defaults to 9, since context defaults to document
		nodeType = context ? context.nodeType : 9;

	results = results || [];

	// Return early from calls with invalid selector or context
	if ( typeof selector !== "string" || !selector ||
		nodeType !== 1 && nodeType !== 9 && nodeType !== 11 ) {

		return results;
	}

	// Try to shortcut find operations (as opposed to filters) in HTML documents
	if ( !seed ) {
		setDocument( context );
		context = context || document;

		if ( documentIsHTML ) {

			// If the selector is sufficiently simple, try using a "get*By*" DOM method
			// (excepting DocumentFragment context, where the methods don't exist)
			if ( nodeType !== 11 && ( match = rquickExpr.exec( selector ) ) ) {

				// ID selector
				if ( ( m = match[ 1 ] ) ) {

					// Document context
					if ( nodeType === 9 ) {
						if ( ( elem = context.getElementById( m ) ) ) {
							push.call( results, elem );
						}
						return results;

					// Element context
					} else {
						if ( newContext && ( elem = newContext.getElementById( m ) ) &&
							jQuery.contains( context, elem ) ) {

							push.call( results, elem );
							return results;
						}
					}

				// Type selector
				} else if ( match[ 2 ] ) {
					push.apply( results, context.getElementsByTagName( selector ) );
					return results;

				// Class selector
				} else if ( ( m = match[ 3 ] ) && context.getElementsByClassName ) {
					push.apply( results, context.getElementsByClassName( m ) );
					return results;
				}
			}

			// Take advantage of querySelectorAll
			if ( !nonnativeSelectorCache[ selector + " " ] &&
				( !rbuggyQSA || !rbuggyQSA.test( selector ) ) ) {

				newSelector = selector;
				newContext = context;

				// qSA considers elements outside a scoping root when evaluating child or
				// descendant combinators, which is not what we want.
				// In such cases, we work around the behavior by prefixing every selector in the
				// list with an ID selector referencing the scope context.
				// The technique has to be used as well when a leading combinator is used
				// as such selectors are not recognized by querySelectorAll.
				// Thanks to Andrew Dupont for this technique.
				if ( nodeType === 1 &&
					( rdescend.test( selector ) || rleadingCombinator.test( selector ) ) ) {

					// Expand context for sibling selectors
					newContext = rsibling.test( selector ) &&
						testContext( context.parentNode ) ||
						context;

					// Outside of IE, if we're not changing the context we can
					// use :scope instead of an ID.
					// Support: IE 11+
					// IE sometimes throws a "Permission denied" error when strict-comparing
					// two documents; shallow comparisons work.
					// eslint-disable-next-line eqeqeq
					if ( newContext != context || isIE ) {

						// Capture the context ID, setting it first if necessary
						if ( ( nid = context.getAttribute( "id" ) ) ) {
							nid = jQuery.escapeSelector( nid );
						} else {
							context.setAttribute( "id", ( nid = jQuery.expando ) );
						}
					}

					// Prefix every selector in the list
					groups = tokenize( selector );
					i = groups.length;
					while ( i-- ) {
						groups[ i ] = ( nid ? "#" + nid : ":scope" ) + " " +
							toSelector( groups[ i ] );
					}
					newSelector = groups.join( "," );
				}

				try {
					push.apply( results,
						newContext.querySelectorAll( newSelector )
					);
					return results;
				} catch ( qsaError ) {
					nonnativeSelectorCache( selector, true );
				} finally {
					if ( nid === jQuery.expando ) {
						context.removeAttribute( "id" );
					}
				}
			}
		}
	}

	// All others
	return select( selector.replace( rtrimCSS, "$1" ), context, results, seed );
}

/**
 * Mark a function for special use by jQuery selector module
 * @param {Function} fn The function to mark
 */
function markFunction( fn ) {
	fn[ jQuery.expando ] = true;
	return fn;
}

/**
 * Returns a function to use in pseudos for input types
 * @param {String} type
 */
function createInputPseudo( type ) {
	return function( elem ) {
		return nodeName( elem, "input" ) && elem.type === type;
	};
}

/**
 * Returns a function to use in pseudos for buttons
 * @param {String} type
 */
function createButtonPseudo( type ) {
	return function( elem ) {
		return ( nodeName( elem, "input" ) || nodeName( elem, "button" ) ) &&
			elem.type === type;
	};
}

/**
 * Returns a function to use in pseudos for :enabled/:disabled
 * @param {Boolean} disabled true for :disabled; false for :enabled
 */
function createDisabledPseudo( disabled ) {

	// Known :disabled false positives: fieldset[disabled] > legend:nth-of-type(n+2) :can-disable
	return function( elem ) {

		// Only certain elements can match :enabled or :disabled
		// https://html.spec.whatwg.org/multipage/scripting.html#selector-enabled
		// https://html.spec.whatwg.org/multipage/scripting.html#selector-disabled
		if ( "form" in elem ) {

			// Check for inherited disabledness on relevant non-disabled elements:
			// * listed form-associated elements in a disabled fieldset
			//   https://html.spec.whatwg.org/multipage/forms.html#category-listed
			//   https://html.spec.whatwg.org/multipage/forms.html#concept-fe-disabled
			// * option elements in a disabled optgroup
			//   https://html.spec.whatwg.org/multipage/forms.html#concept-option-disabled
			// All such elements have a "form" property.
			if ( elem.parentNode && elem.disabled === false ) {

				// Option elements defer to a parent optgroup if present
				if ( "label" in elem ) {
					if ( "label" in elem.parentNode ) {
						return elem.parentNode.disabled === disabled;
					} else {
						return elem.disabled === disabled;
					}
				}

				// Support: IE 6 - 11+
				// Use the isDisabled shortcut property to check for disabled fieldset ancestors
				return elem.isDisabled === disabled ||

					// Where there is no isDisabled, check manually
					elem.isDisabled !== !disabled &&
						inDisabledFieldset( elem ) === disabled;
			}

			return elem.disabled === disabled;

		// Try to winnow out elements that can't be disabled before trusting the disabled property.
		// Some victims get caught in our net (label, legend, menu, track), but it shouldn't
		// even exist on them, let alone have a boolean value.
		} else if ( "label" in elem ) {
			return elem.disabled === disabled;
		}

		// Remaining elements are neither :enabled nor :disabled
		return false;
	};
}

/**
 * Returns a function to use in pseudos for positionals
 * @param {Function} fn
 */
function createPositionalPseudo( fn ) {
	return markFunction( function( argument ) {
		argument = +argument;
		return markFunction( function( seed, matches ) {
			var j,
				matchIndexes = fn( [], seed.length, argument ),
				i = matchIndexes.length;

			// Match elements found at the specified indexes
			while ( i-- ) {
				if ( seed[ ( j = matchIndexes[ i ] ) ] ) {
					seed[ j ] = !( matches[ j ] = seed[ j ] );
				}
			}
		} );
	} );
}

/**
 * Sets document-related variables once based on the current document
 * @param {Element|Object} [node] An element or document object to use to set the document
 */
function setDocument( node ) {
	var subWindow,
		doc = node ? node.ownerDocument || node : preferredDoc;

	// Return early if doc is invalid or already selected
	// Support: IE 11+
	// IE sometimes throws a "Permission denied" error when strict-comparing
	// two documents; shallow comparisons work.
	// eslint-disable-next-line eqeqeq
	if ( doc == document || doc.nodeType !== 9 ) {
		return;
	}

	// Update global variables
	document = doc;
	documentElement = document.documentElement;
	documentIsHTML = !jQuery.isXMLDoc( document );

	// Support: IE 9 - 11+
	// Accessing iframe documents after unload throws "permission denied" errors (see trac-13936)
	// Support: IE 11+
	// IE sometimes throws a "Permission denied" error when strict-comparing
	// two documents; shallow comparisons work.
	// eslint-disable-next-line eqeqeq
	if ( isIE && preferredDoc != document &&
		( subWindow = document.defaultView ) && subWindow.top !== subWindow ) {
		subWindow.addEventListener( "unload", unloadHandler );
	}
}

find.matches = function( expr, elements ) {
	return find( expr, null, null, elements );
};

find.matchesSelector = function( elem, expr ) {
	setDocument( elem );

	if ( documentIsHTML &&
		!nonnativeSelectorCache[ expr + " " ] &&
		( !rbuggyQSA || !rbuggyQSA.test( expr ) ) ) {

		try {
			return matches.call( elem, expr );
		} catch ( e ) {
			nonnativeSelectorCache( expr, true );
		}
	}

	return find( expr, document, null, [ elem ] ).length > 0;
};

jQuery.expr = {

	// Can be adjusted by the user
	cacheLength: 50,

	createPseudo: markFunction,

	match: matchExpr,

	find: {
		ID: function( id, context ) {
			if ( typeof context.getElementById !== "undefined" && documentIsHTML ) {
				var elem = context.getElementById( id );
				return elem ? [ elem ] : [];
			}
		},

		TAG: function( tag, context ) {
			if ( typeof context.getElementsByTagName !== "undefined" ) {
				return context.getElementsByTagName( tag );

				// DocumentFragment nodes don't have gEBTN
			} else {
				return context.querySelectorAll( tag );
			}
		},

		CLASS: function( className, context ) {
			if ( typeof context.getElementsByClassName !== "undefined" && documentIsHTML ) {
				return context.getElementsByClassName( className );
			}
		}
	},

	relative: {
		">": { dir: "parentNode", first: true },
		" ": { dir: "parentNode" },
		"+": { dir: "previousSibling", first: true },
		"~": { dir: "previousSibling" }
	},

	preFilter: preFilter,

	filter: {
		ID: function( id ) {
			var attrId = unescapeSelector( id );
			return function( elem ) {
				return elem.getAttribute( "id" ) === attrId;
			};
		},

		TAG: function( nodeNameSelector ) {
			var expectedNodeName = unescapeSelector( nodeNameSelector ).toLowerCase();
			return nodeNameSelector === "*" ?

				function() {
					return true;
				} :

				function( elem ) {
					return nodeName( elem, expectedNodeName );
				};
		},

		CLASS: function( className ) {
			var pattern = classCache[ className + " " ];

			return pattern ||
				( pattern = new RegExp( "(^|" + whitespace + ")" + className +
					"(" + whitespace + "|$)" ) ) &&
				classCache( className, function( elem ) {
					return pattern.test(
						typeof elem.className === "string" && elem.className ||
							typeof elem.getAttribute !== "undefined" &&
								elem.getAttribute( "class" ) ||
							""
					);
				} );
		},

		ATTR: function( name, operator, check ) {
			return function( elem ) {
				var result = jQuery.attr( elem, name );

				if ( result == null ) {
					return operator === "!=";
				}
				if ( !operator ) {
					return true;
				}

				result += "";

				if ( operator === "=" ) {
					return result === check;
				}
				if ( operator === "!=" ) {
					return result !== check;
				}
				if ( operator === "^=" ) {
					return check && result.indexOf( check ) === 0;
				}
				if ( operator === "*=" ) {
					return check && result.indexOf( check ) > -1;
				}
				if ( operator === "$=" ) {
					return check && result.slice( -check.length ) === check;
				}
				if ( operator === "~=" ) {
					return ( " " + result.replace( rwhitespace, " " ) + " " )
						.indexOf( check ) > -1;
				}
				if ( operator === "|=" ) {
					return result === check || result.slice( 0, check.length + 1 ) === check + "-";
				}

				return false;
			};
		},

		CHILD: function( type, what, _argument, first, last ) {
			var simple = type.slice( 0, 3 ) !== "nth",
				forward = type.slice( -4 ) !== "last",
				ofType = what === "of-type";

			return first === 1 && last === 0 ?

				// Shortcut for :nth-*(n)
				function( elem ) {
					return !!elem.parentNode;
				} :

				function( elem, _context, xml ) {
					var cache, outerCache, node, nodeIndex, start,
						dir = simple !== forward ? "nextSibling" : "previousSibling",
						parent = elem.parentNode,
						name = ofType && elem.nodeName.toLowerCase(),
						useCache = !xml && !ofType,
						diff = false;

					if ( parent ) {

						// :(first|last|only)-(child|of-type)
						if ( simple ) {
							while ( dir ) {
								node = elem;
								while ( ( node = node[ dir ] ) ) {
									if ( ofType ?
										nodeName( node, name ) :
										node.nodeType === 1 ) {

										return false;
									}
								}

								// Reverse direction for :only-* (if we haven't yet done so)
								start = dir = type === "only" && !start && "nextSibling";
							}
							return true;
						}

						start = [ forward ? parent.firstChild : parent.lastChild ];

						// non-xml :nth-child(...) stores cache data on `parent`
						if ( forward && useCache ) {

							// Seek `elem` from a previously-cached index
							outerCache = parent[ jQuery.expando ] ||
								( parent[ jQuery.expando ] = {} );
							cache = outerCache[ type ] || [];
							nodeIndex = cache[ 0 ] === dirruns && cache[ 1 ];
							diff = nodeIndex && cache[ 2 ];
							node = nodeIndex && parent.childNodes[ nodeIndex ];

							while ( ( node = ++nodeIndex && node && node[ dir ] ||

								// Fallback to seeking `elem` from the start
								( diff = nodeIndex = 0 ) || start.pop() ) ) {

								// When found, cache indexes on `parent` and break
								if ( node.nodeType === 1 && ++diff && node === elem ) {
									outerCache[ type ] = [ dirruns, nodeIndex, diff ];
									break;
								}
							}

						} else {

							// Use previously-cached element index if available
							if ( useCache ) {
								outerCache = elem[ jQuery.expando ] ||
									( elem[ jQuery.expando ] = {} );
								cache = outerCache[ type ] || [];
								nodeIndex = cache[ 0 ] === dirruns && cache[ 1 ];
								diff = nodeIndex;
							}

							// xml :nth-child(...)
							// or :nth-last-child(...) or :nth(-last)?-of-type(...)
							if ( diff === false ) {

								// Use the same loop as above to seek `elem` from the start
								while ( ( node = ++nodeIndex && node && node[ dir ] ||
									( diff = nodeIndex = 0 ) || start.pop() ) ) {

									if ( ( ofType ?
										nodeName( node, name ) :
										node.nodeType === 1 ) &&
										++diff ) {

										// Cache the index of each encountered element
										if ( useCache ) {
											outerCache = node[ jQuery.expando ] ||
												( node[ jQuery.expando ] = {} );
											outerCache[ type ] = [ dirruns, diff ];
										}

										if ( node === elem ) {
											break;
										}
									}
								}
							}
						}

						// Incorporate the offset, then check against cycle size
						diff -= last;
						return diff === first || ( diff % first === 0 && diff / first >= 0 );
					}
				};
		},

		PSEUDO: function( pseudo, argument ) {

			// pseudo-class names are case-insensitive
			// https://www.w3.org/TR/selectors/#pseudo-classes
			// Prioritize by case sensitivity in case custom pseudos are added with uppercase letters
			// Remember that setFilters inherits from pseudos
			var fn = jQuery.expr.pseudos[ pseudo ] ||
				jQuery.expr.setFilters[ pseudo.toLowerCase() ] ||
				selectorError( "unsupported pseudo: " + pseudo );

			// The user may use createPseudo to indicate that
			// arguments are needed to create the filter function
			// just as jQuery does
			if ( fn[ jQuery.expando ] ) {
				return fn( argument );
			}

			return fn;
		}
	},

	pseudos: {

		// Potentially complex pseudos
		not: markFunction( function( selector ) {

			// Trim the selector passed to compile
			// to avoid treating leading and trailing
			// spaces as combinators
			var input = [],
				results = [],
				matcher = compile( selector.replace( rtrimCSS, "$1" ) );

			return matcher[ jQuery.expando ] ?
				markFunction( function( seed, matches, _context, xml ) {
					var elem,
						unmatched = matcher( seed, null, xml, [] ),
						i = seed.length;

					// Match elements unmatched by `matcher`
					while ( i-- ) {
						if ( ( elem = unmatched[ i ] ) ) {
							seed[ i ] = !( matches[ i ] = elem );
						}
					}
				} ) :
				function( elem, _context, xml ) {
					input[ 0 ] = elem;
					matcher( input, null, xml, results );

					// Don't keep the element
					// (see https://github.com/jquery/sizzle/issues/299)
					input[ 0 ] = null;
					return !results.pop();
				};
		} ),

		has: markFunction( function( selector ) {
			return function( elem ) {
				return find( selector, elem ).length > 0;
			};
		} ),

		contains: markFunction( function( text ) {
			text = unescapeSelector( text );
			return function( elem ) {
				return ( elem.textContent || jQuery.text( elem ) ).indexOf( text ) > -1;
			};
		} ),

		// "Whether an element is represented by a :lang() selector
		// is based solely on the element's language value
		// being equal to the identifier C,
		// or beginning with the identifier C immediately followed by "-".
		// The matching of C against the element's language value is performed case-insensitively.
		// The identifier C does not have to be a valid language name."
		// https://www.w3.org/TR/selectors/#lang-pseudo
		lang: markFunction( function( lang ) {

			// lang value must be a valid identifier
			if ( !ridentifier.test( lang || "" ) ) {
				selectorError( "unsupported lang: " + lang );
			}
			lang = unescapeSelector( lang ).toLowerCase();
			return function( elem ) {
				var elemLang;
				do {
					if ( ( elemLang = documentIsHTML ?
						elem.lang :
						elem.getAttribute( "xml:lang" ) || elem.getAttribute( "lang" ) ) ) {

						elemLang = elemLang.toLowerCase();
						return elemLang === lang || elemLang.indexOf( lang + "-" ) === 0;
					}
				} while ( ( elem = elem.parentNode ) && elem.nodeType === 1 );
				return false;
			};
		} ),

		// Miscellaneous
		target: function( elem ) {
			var hash = window.location && window.location.hash;
			return hash && hash.slice( 1 ) === elem.id;
		},

		root: function( elem ) {
			return elem === documentElement;
		},

		focus: function( elem ) {
			return elem === document.activeElement &&
				document.hasFocus() &&
				!!( elem.type || elem.href || ~elem.tabIndex );
		},

		// Boolean properties
		enabled: createDisabledPseudo( false ),
		disabled: createDisabledPseudo( true ),

		checked: function( elem ) {

			// In CSS3, :checked should return both checked and selected elements
			// https://www.w3.org/TR/2011/REC-css3-selectors-20110929/#checked
			return ( nodeName( elem, "input" ) && !!elem.checked ) ||
				( nodeName( elem, "option" ) && !!elem.selected );
		},

		selected: function( elem ) {

			// Support: IE <=11+
			// Accessing the selectedIndex property
			// forces the browser to treat the default option as
			// selected when in an optgroup.
			if ( isIE && elem.parentNode ) {
				// eslint-disable-next-line no-unused-expressions
				elem.parentNode.selectedIndex;
			}

			return elem.selected === true;
		},

		// Contents
		empty: function( elem ) {

			// https://www.w3.org/TR/selectors/#empty-pseudo
			// :empty is negated by element (1) or content nodes (text: 3; cdata: 4; entity ref: 5),
			//   but not by others (comment: 8; processing instruction: 7; etc.)
			// nodeType < 6 works because attributes (2) do not appear as children
			for ( elem = elem.firstChild; elem; elem = elem.nextSibling ) {
				if ( elem.nodeType < 6 ) {
					return false;
				}
			}
			return true;
		},

		parent: function( elem ) {
			return !jQuery.expr.pseudos.empty( elem );
		},

		// Element/input types
		header: function( elem ) {
			return rheader.test( elem.nodeName );
		},

		input: function( elem ) {
			return rinputs.test( elem.nodeName );
		},

		button: function( elem ) {
			return nodeName( elem, "input" ) && elem.type === "button" ||
				nodeName( elem, "button" );
		},

		text: function( elem ) {
			return nodeName( elem, "input" ) && elem.type === "text";
		},

		// Position-in-collection
		first: createPositionalPseudo( function() {
			return [ 0 ];
		} ),

		last: createPositionalPseudo( function( _matchIndexes, length ) {
			return [ length - 1 ];
		} ),

		eq: createPositionalPseudo( function( _matchIndexes, length, argument ) {
			return [ argument < 0 ? argument + length : argument ];
		} ),

		even: createPositionalPseudo( function( matchIndexes, length ) {
			var i = 0;
			for ( ; i < length; i += 2 ) {
				matchIndexes.push( i );
			}
			return matchIndexes;
		} ),

		odd: createPositionalPseudo( function( matchIndexes, length ) {
			var i = 1;
			for ( ; i < length; i += 2 ) {
				matchIndexes.push( i );
			}
			return matchIndexes;
		} ),

		lt: createPositionalPseudo( function( matchIndexes, length, argument ) {
			var i;

			if ( argument < 0 ) {
				i = argument + length;
			} else if ( argument > length ) {
				i = length;
			} else {
				i = argument;
			}

			for ( ; --i >= 0; ) {
				matchIndexes.push( i );
			}
			return matchIndexes;
		} ),

		gt: createPositionalPseudo( function( matchIndexes, length, argument ) {
			var i = argument < 0 ? argument + length : argument;
			for ( ; ++i < length; ) {
				matchIndexes.push( i );
			}
			return matchIndexes;
		} )
	}
};

jQuery.expr.pseudos.nth = jQuery.expr.pseudos.eq;

// Add button/input type pseudos
for ( i in { radio: true, checkbox: true, file: true, password: true, image: true } ) {
	jQuery.expr.pseudos[ i ] = createInputPseudo( i );
}
for ( i in { submit: true, reset: true } ) {
	jQuery.expr.pseudos[ i ] = createButtonPseudo( i );
}

// Easy API for creating new setFilters
function setFilters() {}
setFilters.prototype = jQuery.expr.filters = jQuery.expr.pseudos;
jQuery.expr.setFilters = new setFilters();

function addCombinator( matcher, combinator, base ) {
	var dir = combinator.dir,
		skip = combinator.next,
		key = skip || dir,
		checkNonElements = base && key === "parentNode",
		doneName = done++;

	return combinator.first ?

		// Check against closest ancestor/preceding element
		function( elem, context, xml ) {
			while ( ( elem = elem[ dir ] ) ) {
				if ( elem.nodeType === 1 || checkNonElements ) {
					return matcher( elem, context, xml );
				}
			}
			return false;
		} :

		// Check against all ancestor/preceding elements
		function( elem, context, xml ) {
			var oldCache, outerCache,
				newCache = [ dirruns, doneName ];

			// We can't set arbitrary data on XML nodes, so they don't benefit from combinator caching
			if ( xml ) {
				while ( ( elem = elem[ dir ] ) ) {
					if ( elem.nodeType === 1 || checkNonElements ) {
						if ( matcher( elem, context, xml ) ) {
							return true;
						}
					}
				}
			} else {
				while ( ( elem = elem[ dir ] ) ) {
					if ( elem.nodeType === 1 || checkNonElements ) {
						outerCache = elem[ jQuery.expando ] || ( elem[ jQuery.expando ] = {} );

						if ( skip && nodeName( elem, skip ) ) {
							elem = elem[ dir ] || elem;
						} else if ( ( oldCache = outerCache[ key ] ) &&
							oldCache[ 0 ] === dirruns && oldCache[ 1 ] === doneName ) {

							// Assign to newCache so results back-propagate to previous elements
							return ( newCache[ 2 ] = oldCache[ 2 ] );
						} else {

							// Reuse newcache so results back-propagate to previous elements
							outerCache[ key ] = newCache;

							// A match means we're done; a fail means we have to keep checking
							if ( ( newCache[ 2 ] = matcher( elem, context, xml ) ) ) {
								return true;
							}
						}
					}
				}
			}
			return false;
		};
}

function elementMatcher( matchers ) {
	return matchers.length > 1 ?
		function( elem, context, xml ) {
			var i = matchers.length;
			while ( i-- ) {
				if ( !matchers[ i ]( elem, context, xml ) ) {
					return false;
				}
			}
			return true;
		} :
		matchers[ 0 ];
}

function multipleContexts( selector, contexts, results ) {
	var i = 0,
		len = contexts.length;
	for ( ; i < len; i++ ) {
		find( selector, contexts[ i ], results );
	}
	return results;
}

function condense( unmatched, map, filter, context, xml ) {
	var elem,
		newUnmatched = [],
		i = 0,
		len = unmatched.length,
		mapped = map != null;

	for ( ; i < len; i++ ) {
		if ( ( elem = unmatched[ i ] ) ) {
			if ( !filter || filter( elem, context, xml ) ) {
				newUnmatched.push( elem );
				if ( mapped ) {
					map.push( i );
				}
			}
		}
	}

	return newUnmatched;
}

function setMatcher( preFilter, selector, matcher, postFilter, postFinder, postSelector ) {
	if ( postFilter && !postFilter[ jQuery.expando ] ) {
		postFilter = setMatcher( postFilter );
	}
	if ( postFinder && !postFinder[ jQuery.expando ] ) {
		postFinder = setMatcher( postFinder, postSelector );
	}
	return markFunction( function( seed, results, context, xml ) {
		var temp, i, elem, matcherOut,
			preMap = [],
			postMap = [],
			preexisting = results.length,

			// Get initial elements from seed or context
			elems = seed ||
				multipleContexts( selector || "*",
					context.nodeType ? [ context ] : context, [] ),

			// Prefilter to get matcher input, preserving a map for seed-results synchronization
			matcherIn = preFilter && ( seed || !selector ) ?
				condense( elems, preMap, preFilter, context, xml ) :
				elems;

		if ( matcher ) {

			// If we have a postFinder, or filtered seed, or non-seed postFilter
			// or preexisting results,
			matcherOut = postFinder || ( seed ? preFilter : preexisting || postFilter ) ?

				// ...intermediate processing is necessary
				[] :

				// ...otherwise use results directly
				results;

			// Find primary matches
			matcher( matcherIn, matcherOut, context, xml );
		} else {
			matcherOut = matcherIn;
		}

		// Apply postFilter
		if ( postFilter ) {
			temp = condense( matcherOut, postMap );
			postFilter( temp, [], context, xml );

			// Un-match failing elements by moving them back to matcherIn
			i = temp.length;
			while ( i-- ) {
				if ( ( elem = temp[ i ] ) ) {
					matcherOut[ postMap[ i ] ] = !( matcherIn[ postMap[ i ] ] = elem );
				}
			}
		}

		if ( seed ) {
			if ( postFinder || preFilter ) {
				if ( postFinder ) {

					// Get the final matcherOut by condensing this intermediate into postFinder contexts
					temp = [];
					i = matcherOut.length;
					while ( i-- ) {
						if ( ( elem = matcherOut[ i ] ) ) {

							// Restore matcherIn since elem is not yet a final match
							temp.push( ( matcherIn[ i ] = elem ) );
						}
					}
					postFinder( null, ( matcherOut = [] ), temp, xml );
				}

				// Move matched elements from seed to results to keep them synchronized
				i = matcherOut.length;
				while ( i-- ) {
					if ( ( elem = matcherOut[ i ] ) &&
						( temp = postFinder ? indexOf.call( seed, elem ) : preMap[ i ] ) > -1 ) {

						seed[ temp ] = !( results[ temp ] = elem );
					}
				}
			}

		// Add elements to results, through postFinder if defined
		} else {
			matcherOut = condense(
				matcherOut === results ?
					matcherOut.splice( preexisting, matcherOut.length ) :
					matcherOut
			);
			if ( postFinder ) {
				postFinder( null, results, matcherOut, xml );
			} else {
				push.apply( results, matcherOut );
			}
		}
	} );
}

function matcherFromTokens( tokens ) {
	var checkContext, matcher, j,
		len = tokens.length,
		leadingRelative = jQuery.expr.relative[ tokens[ 0 ].type ],
		implicitRelative = leadingRelative || jQuery.expr.relative[ " " ],
		i = leadingRelative ? 1 : 0,

		// The foundational matcher ensures that elements are reachable from top-level context(s)
		matchContext = addCombinator( function( elem ) {
			return elem === checkContext;
		}, implicitRelative, true ),
		matchAnyContext = addCombinator( function( elem ) {
			return indexOf.call( checkContext, elem ) > -1;
		}, implicitRelative, true ),
		matchers = [ function( elem, context, xml ) {

			// Support: IE 11+
			// IE sometimes throws a "Permission denied" error when strict-comparing
			// two documents; shallow comparisons work.
			// eslint-disable-next-line eqeqeq
			var ret = ( !leadingRelative && ( xml || context != outermostContext ) ) || (
				( checkContext = context ).nodeType ?
					matchContext( elem, context, xml ) :
					matchAnyContext( elem, context, xml ) );

			// Avoid hanging onto element
			// (see https://github.com/jquery/sizzle/issues/299)
			checkContext = null;
			return ret;
		} ];

	for ( ; i < len; i++ ) {
		if ( ( matcher = jQuery.expr.relative[ tokens[ i ].type ] ) ) {
			matchers = [ addCombinator( elementMatcher( matchers ), matcher ) ];
		} else {
			matcher = jQuery.expr.filter[ tokens[ i ].type ].apply( null, tokens[ i ].matches );

			// Return special upon seeing a positional matcher
			if ( matcher[ jQuery.expando ] ) {

				// Find the next relative operator (if any) for proper handling
				j = ++i;
				for ( ; j < len; j++ ) {
					if ( jQuery.expr.relative[ tokens[ j ].type ] ) {
						break;
					}
				}
				return setMatcher(
					i > 1 && elementMatcher( matchers ),
					i > 1 && toSelector(

						// If the preceding token was a descendant combinator, insert an implicit any-element `*`
						tokens.slice( 0, i - 1 )
							.concat( { value: tokens[ i - 2 ].type === " " ? "*" : "" } )
					).replace( rtrimCSS, "$1" ),
					matcher,
					i < j && matcherFromTokens( tokens.slice( i, j ) ),
					j < len && matcherFromTokens( ( tokens = tokens.slice( j ) ) ),
					j < len && toSelector( tokens )
				);
			}
			matchers.push( matcher );
		}
	}

	return elementMatcher( matchers );
}

function matcherFromGroupMatchers( elementMatchers, setMatchers ) {
	var bySet = setMatchers.length > 0,
		byElement = elementMatchers.length > 0,
		superMatcher = function( seed, context, xml, results, outermost ) {
			var elem, j, matcher,
				matchedCount = 0,
				i = "0",
				unmatched = seed && [],
				setMatched = [],
				contextBackup = outermostContext,

				// We must always have either seed elements or outermost context
				elems = seed || byElement && jQuery.expr.find.TAG( "*", outermost ),

				// Use integer dirruns iff this is the outermost matcher
				dirrunsUnique = ( dirruns += contextBackup == null ? 1 : Math.random() || 0.1 );

			if ( outermost ) {

				// Support: IE 11+
				// IE sometimes throws a "Permission denied" error when strict-comparing
				// two documents; shallow comparisons work.
				// eslint-disable-next-line eqeqeq
				outermostContext = context == document || context || outermost;
			}

			// Add elements passing elementMatchers directly to results
			for ( ; ( elem = elems[ i ] ) != null; i++ ) {
				if ( byElement && elem ) {
					j = 0;

					// Support: IE 11+
					// IE sometimes throws a "Permission denied" error when strict-comparing
					// two documents; shallow comparisons work.
					// eslint-disable-next-line eqeqeq
					if ( !context && elem.ownerDocument != document ) {
						setDocument( elem );
						xml = !documentIsHTML;
					}
					while ( ( matcher = elementMatchers[ j++ ] ) ) {
						if ( matcher( elem, context || document, xml ) ) {
							push.call( results, elem );
							break;
						}
					}
					if ( outermost ) {
						dirruns = dirrunsUnique;
					}
				}

				// Track unmatched elements for set filters
				if ( bySet ) {

					// They will have gone through all possible matchers
					if ( ( elem = !matcher && elem ) ) {
						matchedCount--;
					}

					// Lengthen the array for every element, matched or not
					if ( seed ) {
						unmatched.push( elem );
					}
				}
			}

			// `i` is now the count of elements visited above, and adding it to `matchedCount`
			// makes the latter nonnegative.
			matchedCount += i;

			// Apply set filters to unmatched elements
			// NOTE: This can be skipped if there are no unmatched elements (i.e., `matchedCount`
			// equals `i`), unless we didn't visit _any_ elements in the above loop because we have
			// no element matchers and no seed.
			// Incrementing an initially-string "0" `i` allows `i` to remain a string only in that
			// case, which will result in a "00" `matchedCount` that differs from `i` but is also
			// numerically zero.
			if ( bySet && i !== matchedCount ) {
				j = 0;
				while ( ( matcher = setMatchers[ j++ ] ) ) {
					matcher( unmatched, setMatched, context, xml );
				}

				if ( seed ) {

					// Reintegrate element matches to eliminate the need for sorting
					if ( matchedCount > 0 ) {
						while ( i-- ) {
							if ( !( unmatched[ i ] || setMatched[ i ] ) ) {
								setMatched[ i ] = pop.call( results );
							}
						}
					}

					// Discard index placeholder values to get only actual matches
					setMatched = condense( setMatched );
				}

				// Add matches to results
				push.apply( results, setMatched );

				// Seedless set matches succeeding multiple successful matchers stipulate sorting
				if ( outermost && !seed && setMatched.length > 0 &&
					( matchedCount + setMatchers.length ) > 1 ) {

					jQuery.uniqueSort( results );
				}
			}

			// Override manipulation of globals by nested matchers
			if ( outermost ) {
				dirruns = dirrunsUnique;
				outermostContext = contextBackup;
			}

			return unmatched;
		};

	return bySet ?
		markFunction( superMatcher ) :
		superMatcher;
}

function compile( selector, match /* Internal Use Only */ ) {
	var i,
		setMatchers = [],
		elementMatchers = [],
		cached = compilerCache[ selector + " " ];

	if ( !cached ) {

		// Generate a function of recursive functions that can be used to check each element
		if ( !match ) {
			match = tokenize( selector );
		}
		i = match.length;
		while ( i-- ) {
			cached = matcherFromTokens( match[ i ] );
			if ( cached[ jQuery.expando ] ) {
				setMatchers.push( cached );
			} else {
				elementMatchers.push( cached );
			}
		}

		// Cache the compiled function
		cached = compilerCache( selector,
			matcherFromGroupMatchers( elementMatchers, setMatchers ) );

		// Save selector and tokenization
		cached.selector = selector;
	}
	return cached;
}

/**
 * A low-level selection function that works with jQuery's compiled
 *  selector functions
 * @param {String|Function} selector A selector or a pre-compiled
 *  selector function built with jQuery selector compile
 * @param {Element} context
 * @param {Array} [results]
 * @param {Array} [seed] A set of elements to match against
 */
function select( selector, context, results, seed ) {
	var i, tokens, token, type, find,
		compiled = typeof selector === "function" && selector,
		match = !seed && tokenize( ( selector = compiled.selector || selector ) );

	results = results || [];

	// Try to minimize operations if there is only one selector in the list and no seed
	// (the latter of which guarantees us context)
	if ( match.length === 1 ) {

		// Reduce context if the leading compound selector is an ID
		tokens = match[ 0 ] = match[ 0 ].slice( 0 );
		if ( tokens.length > 2 && ( token = tokens[ 0 ] ).type === "ID" &&
				context.nodeType === 9 && documentIsHTML &&
				jQuery.expr.relative[ tokens[ 1 ].type ] ) {

			context = ( jQuery.expr.find.ID(
				unescapeSelector( token.matches[ 0 ] ),
				context
			) || [] )[ 0 ];
			if ( !context ) {
				return results;

			// Precompiled matchers will still verify ancestry, so step up a level
			} else if ( compiled ) {
				context = context.parentNode;
			}

			selector = selector.slice( tokens.shift().value.length );
		}

		// Fetch a seed set for right-to-left matching
		i = matchExpr.needsContext.test( selector ) ? 0 : tokens.length;
		while ( i-- ) {
			token = tokens[ i ];

			// Abort if we hit a combinator
			if ( jQuery.expr.relative[ ( type = token.type ) ] ) {
				break;
			}
			if ( ( find = jQuery.expr.find[ type ] ) ) {

				// Search, expanding context for leading sibling combinators
				if ( ( seed = find(
					unescapeSelector( token.matches[ 0 ] ),
					rsibling.test( tokens[ 0 ].type ) &&
						testContext( context.parentNode ) || context
				) ) ) {

					// If seed is empty or no tokens remain, we can return early
					tokens.splice( i, 1 );
					selector = seed.length && toSelector( tokens );
					if ( !selector ) {
						push.apply( results, seed );
						return results;
					}

					break;
				}
			}
		}
	}

	// Compile and execute a filtering function if one is not provided
	// Provide `match` to avoid retokenization if we modified the selector above
	( compiled || compile( selector, match ) )(
		seed,
		context,
		!documentIsHTML,
		results,
		!context || rsibling.test( selector ) && testContext( context.parentNode ) || context
	);
	return results;
}

// Initialize against the default document
setDocument();

jQuery.find = find;

// These have always been private, but they used to be documented as part of
// Sizzle so let's maintain them for now for backwards compatibility purposes.
find.compile = compile;
find.select = select;
find.setDocument = setDocument;
find.tokenize = tokenize;

export { jQuery, jQuery as $ };