iska
132 lines
3.3 KiB
Objective-C
132 lines
3.3 KiB
Objective-C
//
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// CSSNthExpressionSelector.m
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// HTMLKit
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//
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// Created by Iska on 10/10/15.
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// Copyright © 2015 BrainCookie. All rights reserved.
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//
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#import "CSSNthExpressionSelector.h"
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#import "HTMLElement.h"
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#import "HTMLNode+Private.h"
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#pragma mark - Nth-Expression
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const CSSNthExpression CSSNthExpressionOdd = (CSSNthExpression) {
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.an = 2, .b = 1
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};
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const CSSNthExpression CSSNthExpressionEven = (CSSNthExpression) {
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.an = 2, .b = 0
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};
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NSString * _Nonnull NSStringFromNthExpression(CSSNthExpression expression)
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{
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if (expression.an == 0 && expression.b == 0) {
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return @"invalid";
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}
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if (expression.an == 0) {
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return [NSString stringWithFormat:@"%ld", (long)expression.b];
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}
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if (expression.b == 0) {
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return [NSString stringWithFormat:@"%ldn", (long)expression.an];
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}
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return [NSString stringWithFormat:@"%ldn%+ld", (long)expression.an, (long)expression.b];
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}
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#pragma mark - Implementation
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NSInteger computeIndex(NSEnumerator *enumerator, HTMLElement *element)
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{
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NSInteger index = 0;
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for (HTMLNode *node in enumerator) {
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if (node.nodeType != HTMLNodeElement) {
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continue;
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}
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if ([node.asElement.tagName isEqualToString:element.tagName]) {
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index++;
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}
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if (node == element) {
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break;
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}
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}
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return index;
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}
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@interface CSSNthExpressionSelector ()
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{
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NSString *_className;
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CSSNthExpression _expression;
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NSInteger (^ _computeIndex)(HTMLElement *);
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}
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@end
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@implementation CSSNthExpressionSelector
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@synthesize expression = _expression;
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@synthesize className = _className;
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+ (instancetype)nthChildSelector:(CSSNthExpression)expression
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{
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return [[self alloc] initWithClassName:@"nth-child" expression:expression block:^NSInteger(HTMLElement *element) {
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return [element.parentElement indexOfChildElement:element] + 1;
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}];
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}
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+ (instancetype)nthLastChildSelector:(CSSNthExpression)expression
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{
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return [[self alloc] initWithClassName:@"nth-last-child" expression:expression block:^NSInteger(HTMLElement *element) {
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return element.parentElement.childElementsCount - [element.parentElement indexOfChildElement:element];
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}];
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}
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+ (instancetype)nthOfTypeSelector:(CSSNthExpression)expression
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{
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return [[self alloc] initWithClassName:@"nth-of-type" expression:expression block:^NSInteger(HTMLElement *element) {
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return computeIndex(element.parentElement.childNodes.array.objectEnumerator, element);
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}];
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}
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+ (instancetype)nthLastOfTypeSelector:(CSSNthExpression)expression
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{
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return [[self alloc] initWithClassName:@"nth-last-of-type" expression:expression block:^NSInteger(HTMLElement *element) {
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return computeIndex(element.parentElement.childNodes.array.reverseObjectEnumerator, element);
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}];
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}
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- (instancetype)initWithClassName:(NSString *)className
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expression:(CSSNthExpression)expression
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block:(NSInteger (^)(HTMLElement *element))block
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{
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self = [super init];
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if (self) {
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_className = [className copy];
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_expression = expression;
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_computeIndex = [block copy];
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}
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return self;
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}
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- (BOOL)acceptElement:(HTMLElement *)element
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{
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NSInteger index = _computeIndex(element);
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if (_expression.an == 0) {
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return index == _expression.b;
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} else {
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NSInteger diff = (index - _expression.b);
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return (diff * _expression.an >= 0) && (diff % _expression.an == 0);
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}
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}
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- (NSString *)debugDescription
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{
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return [NSString stringWithFormat:@":%@(%@)", self.className, NSStringFromNthExpression(self.expression)];
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}
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@end
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