iska
427 lines
12 KiB
Objective-C
427 lines
12 KiB
Objective-C
//
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// CSSSelectorParser.m
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// HTMLKit
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//
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// Created by Iska on 02/10/15.
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// Copyright © 2015 BrainCookie. All rights reserved.
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//
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#import "CSSSelectorParser.h"
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#import "CSSInputStream.h"
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#import "CSSCodePoints.h"
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#import "CSSSelectors.h"
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#import "NSString+Private.h"
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#import "NSCharacterSet+HTMLKit.h"
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#import "CSSNthExpressionParser.h"
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#import "CSSCompoundSelector.h"
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#import "HTMLKitErrorDomain.h"
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@interface CSSSelectorParser ()
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{
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NSString *_string;
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CSSInputStream *_inputStream;
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NSUInteger _location;
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NSMutableArray *_selectors;
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}
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@end
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@implementation CSSSelectorParser
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+ (CSSSelector *)parseSelector:(NSString *)string error:(NSError * __autoreleasing *)error
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{
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CSSSelectorParser *parser = [[CSSSelectorParser alloc] initWithString:string];
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CSSSelector *selector = [parser parse:error];
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return selector;
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}
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#pragma mark - Init
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- (instancetype)initWithString:(NSString *)string
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{
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self = [super init];
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if (self) {
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_string = [self preprocessInput:string];
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_location = 0;
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}
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return self;
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}
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- (NSString *)preprocessInput:(NSString *)string
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{
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string = [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
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string = [string stringByReplacingOccurrencesOfString:@"\r\n" withString:@"\n"];
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string = [string stringByReplacingOccurrencesOfString:@"\r" withString:@"\n"];
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string = [string stringByReplacingOccurrencesOfString:@"\f" withString:@"\n"];
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string = [string stringByReplacingOccurrencesOfString:@"\0" withString:@"\uFFFD"];
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return string;
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}
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#pragma mark - Errors
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- (void)emitError:(NSError * __autoreleasing *)error reason:(NSString *)reason
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{
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[self emitError:error reason:reason location:_location + _inputStream.currentLocation];
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}
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- (void)emitError:(NSError * __autoreleasing *)error reason:(NSString *)reason location:(NSUInteger)location
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{
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NSDictionary *userInfo = @{
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NSLocalizedDescriptionKey: @"Error parsing selector",
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NSLocalizedFailureReasonErrorKey: reason,
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CSSSelectorStringKey: _string,
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CSSSelectorErrorLocationKey: @(location)
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};
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if(error && *error == nil) {
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*error = [NSError errorWithDomain:HTMLKitSelectorErrorDomain code:HTMLKitSelectorParseError userInfo:userInfo];
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}
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}
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#pragma mark - Parsing
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- (CSSSelector *)parse:(NSError * __autoreleasing *)error
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{
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if (_string.length == 0) {
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[self emitError:error reason:@"Empty selector" location:0];
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return nil;
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}
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NSArray *allSubSelectors = [_string componentsSeparatedByString:@","];
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NSMutableArray *parsed = [NSMutableArray array];
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for (NSString *subSelector in allSubSelectors) {
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if ([subSelector isEqualToString:@""]) {
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[self emitError:error reason:@"Empty selector" location:_location];
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break;
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}
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CSSSelector *selector = [self parseSelector:subSelector error:error];
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if (selector == nil) {
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break;
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}
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[parsed addObject:selector];
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_location += subSelector.length;
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}
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if (error && *error != nil) {
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return nil;
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}
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if (parsed.count > 1) {
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return anyOf(parsed);
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}
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return parsed.firstObject;
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}
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- (CSSSelector *)parseSelector:(NSString *)selectorString error:(NSError * __autoreleasing *)error
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{
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_inputStream = [[CSSInputStream alloc] initWithString:selectorString];
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[_inputStream consumeWhitespace];
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CSSSelector *result = nil;
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while (YES) {
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CSSSelector *selector = [self parseSequenceOfSimpleSelectors:error];
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if (selector == nil) {
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break;
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}
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result = result ? allOf(@[result, selector]) : selector;
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UTF32Char next = _inputStream.nextInputCharacter;
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if (isCombinator(next)) {
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NSString *combinator = [_inputStream consumeCombinator];
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if ([combinator isEqualToString:@""]) {
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result = descendantOfElementSelector(result);
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} else if ([combinator isEqualToString:@">"]) {
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result = childOfElementSelector(result);
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} else if ([combinator isEqualToString:@"+"]) {
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result = adjacentSiblingSelector(result);
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} else if ([combinator isEqualToString:@"~"]) {
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result = generalSiblingSelector(result);
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}
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}
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}
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return result;
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}
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- (CSSSelector *)parseSequenceOfSimpleSelectors:(NSError * __autoreleasing *)error
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{
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NSMutableArray *selectors = [NSMutableArray array];
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CSSSelector *typeSelector = [self parseTypeSelector:error];
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if (typeSelector != nil) {
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[selectors addObject:typeSelector];
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}
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while (YES) {
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UTF32Char next = _inputStream.nextInputCharacter;
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if (next == EOF || isCombinator(next)) {
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break;
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}
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CSSSelector *simpleSelector = [self parseSimpleSelector:error];
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if (simpleSelector == nil) {
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return nil;
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}
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[selectors addObject:simpleSelector];
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}
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if (selectors.count > 1) {
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return allOf(selectors);
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}
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return selectors.firstObject;
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}
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- (CSSSelector *)parseTypeSelector:(NSError * __autoreleasing *)error
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{
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NSString *identifier = [_inputStream consumeIdentifier];
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if (identifier != nil) {
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return typeSelector(identifier);
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}
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if ([_inputStream consumeCharacter:ASTERIX]) {
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return universalSelector();
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}
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return nil;
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}
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- (CSSSelector *)parseSimpleSelector:(NSError * __autoreleasing *)error
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{
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CSSSelector *typeSelector = [self parseTypeSelector:error];
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if (typeSelector != nil) {
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return typeSelector;
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}
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UTF32Char codePoint = [_inputStream consumeNextInputCharacter];
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switch (codePoint) {
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case NUMBER_SIGN:
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{
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NSString *elementId = [_inputStream consumeIdentifier];
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if (elementId == nil) {
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[self emitError:error reason:@"Invalid character"];
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return nil;
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}
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return idSelector(elementId);
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}
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case FULL_STOP:
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{
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NSString *className = [_inputStream consumeIdentifier];
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if (className == nil) {
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[self emitError:error reason:@"Invalid character"];
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return nil;
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}
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return classSelector(className);
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}
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case LEFT_SQUARE_BRACKET:
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{
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return [self parseAttributeSelector:error];
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}
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case COLON:
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{
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return [self parsePseudoSelector:error];
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}
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default:
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{
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[self emitError:error reason:@"Invalid character"];
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return nil;
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}
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}
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}
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- (CSSSelector *)parseAttributeSelector:(NSError * __autoreleasing *)error
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{
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NSString *attribute = [_inputStream consumeIdentifier];
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if (attribute == nil) {
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[self emitError:error reason:@"Invalid character" location:_location + _inputStream.currentLocation + 1];
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return nil;
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}
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[_inputStream consumeWhitespace];
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CSSAttributeSelectorType type = CSSAttributeSelectorExists;
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NSString *operator = [_inputStream consumeCharactersInString:@"=~|^$*!"];
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if ([operator isEqualToString:@"="]) {
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type = CSSAttributeSelectorExactMatch;
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} else if ([operator isEqualToString:@"~="]) {
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type = CSSAttributeSelectorIncludes;
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} else if ([operator isEqualToString:@"|="]) {
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type = CSSAttributeSelectorHyphen;
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} else if ([operator isEqualToString:@"^="]) {
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type = CSSAttributeSelectorBegins;
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} else if ([operator isEqualToString:@"$="]) {
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type = CSSAttributeSelectorEnds;
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} else if ([operator isEqualToString:@"*="]) {
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type = CSSAttributeSelectorContains;
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} else if ([operator isEqualToString:@"!="]) {
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type = CSSAttributeSelectorNot;
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}
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NSString *value = nil;
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[_inputStream consumeWhitespace];
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UTF32Char next = _inputStream.nextInputCharacter;
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if (isQuote(next)) {
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UTF32Char quote = [_inputStream consumeNextInputCharacter];
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value = [_inputStream consumeStringWithEndingCodePoint:quote];
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} else {
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value = [_inputStream consumeIdentifier];
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}
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[_inputStream consumeWhitespace];
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// Consume RIGHT_SQUARE_BRACKET
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if (![_inputStream consumeCharacter:RIGHT_SQUARE_BRACKET]) {
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[self emitError:error reason:@"Expected closing right square bracket ']'"];
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}
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if (type == CSSAttributeSelectorExists) {
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return hasAttributeSelector(attribute);
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}
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return attributeSelector(type, attribute, value);
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}
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- (CSSSelector *)parsePseudoSelector:(NSError * __autoreleasing *)error
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{
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NSString *pseudoClass = [_inputStream consumeIdentifier];
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if ([pseudoClass hasPrefix:@"nth"]) {
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[_inputStream consumeWhitespace];
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if (![_inputStream consumeCharacter:LEFT_PARENTHESIS]) {
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[self emitError:error reason:@"Expected opening left parenthesis '('"];
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}
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NSString *functionExpression = [_inputStream consumeCharactersUpToString:@")"];
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CSSNthExpression expression = [CSSNthExpressionParser parseExpression:functionExpression];
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[_inputStream consumeWhitespace];
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if (![_inputStream consumeCharacter:RIGHT_PARENTHESIS]) {
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[self emitError:error reason:@"Expected closing right parenthesis ')'"];
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}
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if ([pseudoClass isEqualToString:@"nth-child"]) {
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return nthChildSelector(expression);
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} else if ([pseudoClass isEqualToString:@"nth-last-child"]) {
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return nthLastChildSelector(expression);
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} else if ([pseudoClass isEqualToString:@"nth-of-type"]) {
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return nthOfTypeSelector(expression);
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} else if ([pseudoClass isEqualToString:@"nth-last-of-type"]) {
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return nthLastOfTypeSelector(expression);
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}
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} else if ([pseudoClass isEqualToString:@"not"]) {
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[_inputStream consumeWhitespace];
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if (![_inputStream consumeCharacter:LEFT_PARENTHESIS]) {
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[self emitError:error reason:@"Expected opening left parenthesis '('"];
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}
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CSSSelector *subSelector = [self parseSimpleSelector:error];
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[_inputStream consumeWhitespace];
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if (![_inputStream consumeCharacter:RIGHT_PARENTHESIS]) {
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[self emitError:error reason:@"Expected closing right parenthesis ')'"];
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}
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return not(subSelector);
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} else if ([pseudoClass isEqualToAny:@"lt", @"gt", @"eq", nil]) {
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[_inputStream consumeWhitespace];
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if (![_inputStream consumeCharacter:LEFT_PARENTHESIS]) {
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[self emitError:error reason:@"Expected opening left parenthesis '('"];
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}
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NSDecimal decimal;
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if (![_inputStream consumeDecimalNumber:&decimal]) {
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[self emitError:error reason:@"Expected a decimal number"];
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}
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[_inputStream consumeWhitespace];
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if (![_inputStream consumeCharacter:RIGHT_PARENTHESIS]) {
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[self emitError:error reason:@"Expected closing right parenthesis ')'"];
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}
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NSDecimalNumber *number = [[NSDecimalNumber alloc] initWithDecimal:decimal];
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if ([pseudoClass isEqualToString:@"lt"]) {
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return ltSelector(number.integerValue);
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} else if ([pseudoClass isEqualToString:@"gt"]) {
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return gtSelector(number.integerValue);
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} else if ([pseudoClass isEqualToString:@"eq"]) {
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return eqSelector(number.integerValue);
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}
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} else {
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if ([pseudoClass isEqualToString:@"even"]) {
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return evenSlector();
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} else if ([pseudoClass isEqualToString:@"odd"]) {
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return oddSelector();
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} else if ([pseudoClass isEqualToString:@"first-child"]) {
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return firstChildSelector();
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} else if ([pseudoClass isEqualToString:@"last-child"]) {
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return lastChildSelector();
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} else if ([pseudoClass isEqualToString:@"first-of-type"]) {
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return firstOfTypeSelector();
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} else if ([pseudoClass isEqualToString:@"last-of-type"]) {
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return lastOfTypeSelector();
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} else if ([pseudoClass isEqualToString:@"only-child"]) {
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return onlyChildSelector();
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} else if ([pseudoClass isEqualToString:@"only-of-type"]) {
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return onlyOfTypeSelector();
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} else if ([pseudoClass isEqualToString:@"root"]) {
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return rootSelector();
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} else if ([pseudoClass isEqualToString:@"empty"]) {
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return emptySelector();
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} else if ([pseudoClass isEqualToString:@"link"]) {
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return linkSelector();
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} else if ([pseudoClass isEqualToString:@"enabled"]) {
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return enabledSelector();
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} else if ([pseudoClass isEqualToString:@"disabled"]) {
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return disabledSelector();
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} else if ([pseudoClass isEqualToString:@"checked"]) {
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return checkedSelector();
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}
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else if ([pseudoClass isEqualToString:@"button"]) {
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return buttonSelector();
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} else if ([pseudoClass isEqualToString:@"checkbox"]) {
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return checkboxSelector();
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} else if ([pseudoClass isEqualToString:@"file"]) {
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return fileSelector();
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} else if ([pseudoClass isEqualToString:@"header"]) {
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return headerSelector();
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} else if ([pseudoClass isEqualToString:@"image"]) {
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return imageSelector();
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} else if ([pseudoClass isEqualToString:@"optional"]) {
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return optionalSelector();
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} else if ([pseudoClass isEqualToString:@"parent"]) {
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return parentSelector();
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} else if ([pseudoClass isEqualToString:@"password"]) {
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return passwordSelector();
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} else if ([pseudoClass isEqualToString:@"radio"]) {
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return radioSelector();
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} else if ([pseudoClass isEqualToString:@"reset"]) {
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return resetSelector();
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} else if ([pseudoClass isEqualToString:@"submit"]) {
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return submitSelector();
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} else if ([pseudoClass isEqualToString:@"text"]) {
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return textSelector();
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} else if ([pseudoClass isEqualToString:@"required"]) {
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return requiredSelector();
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} else if ([pseudoClass isEqualToString:@"reset"]) {
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return resetSelector();
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}
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}
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NSString *reason = [NSString stringWithFormat:@"Unknown pseudo class: %@", pseudoClass];
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[self emitError:error reason:reason];
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return nil;
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}
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@end
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