CSSSelectorTree.m

//
//  CSSSelectorTree.m
//  CSSSample
//
//  Created by Sam Stewart on 7/16/11.
//  Copyright 2011 Float:Right Ltd. All rights reserved.
//
/**
 @class CSSSelectorTree 
 This custom data structure represents our css tree we inflate after parsing. In fact, it's not really a tree but more of a list of matching "paths".
 
 An example will hopefully clarify this:
 */
#import "CSSSelectorTree.h"
#import "CSSSelector.h"


@implementation CSSSelectorTree
@dynamic score;
@synthesize nodes, rules, selector;

- (id)initWithSelector:(CSSSelector *)selector_arg {
    self = [super init];
    if (self) {
        selector = [selector_arg retain];
    }
    return self;
}
/** Convenience method for breaking up multi level selector
 into multiple smaller selectors wrapped in subtrees. Builds the subtrees in reverse order of specificity.*/
+ (NSArray*)subtreesFromSelector:(NSString *)selector {
    NSArray *comps = [selector componentsSeparatedByString:@" "];
    
    NSMutableArray *subtrees = [NSMutableArray arrayWithCapacity:20];
    for (NSString *comp in comps) {
        CSSSelector *selector = [[CSSSelector alloc] initWithSelectorStr:comp];
        CSSSelectorTree *subtree = [[CSSSelectorTree alloc] initWithSelector:selector];
        
        // make sure it's in reverse order.
        [subtrees insertObject:subtree atIndex:0];
    }
    return subtrees;
}

+ (CSSSelectorTree*)chainSubtrees:(NSArray *)subtrees {
    if (![subtrees count]) return nil;
    
    //start with most specific and begin chaining
    CSSSelectorTree *cur_parent = [subtrees objectAtIndex:0];
    CSSSelectorTree *top_parent = cur_parent;
    
    for (CSSSelectorTree *subtree in subtrees) {
        if (subtree != cur_parent) {
            [cur_parent.nodes addObject:subtree];
            cur_parent = subtree; //move into subtree
        }
    }
    return top_parent;
}
#pragma mark Accessors
- (void)sortNodes {
    [nodes sortUsingComparator:(NSComparator)^(CSSSelector *a_sel, CSSSelector *b_sel) {
        NSInteger a_score = [a_sel score];
        NSInteger b_score = [b_sel score];
        
        if (a_score < b_score)
            return NSOrderedAscending;
        else if(a_score > b_score)
            return NSOrderedDescending;
        else
            return NSOrderedSame;
    }];
}
/** Searches subnodes for partial matches for the selector you pass in.
 Remember, only a few properties have to match for the entire selector to match.
 @return Array of CSSSelectorTree nodes.
 */
- (NSArray*)find:(CSSSelector *)selector_arg {
    NSMutableArray *results = [NSMutableArray arrayWithCapacity:20];
    for (CSSSelectorTree *node in nodes) {
        if ([node.selector doesMatchIntoSelector:selector_arg]) {
            [results addObject:node];
        }
    }
    return results;
}

- (BOOL)isLeaf {
    return (nodes.count ? NO : YES);
}
- (NSString*)name {
    // grab our selector entire selector string..
    return selector.selector;
}
/** Takes the biggest child score to ensure we reflect the child nodes accurately.
 Note: this may not be quite right. How do we know we "own" the biggest node?*/
- (NSInteger)score {
    NSInteger max_score = 0;
    for (CSSSelectorTree *node in nodes) {
        NSInteger score = [node score];
        max_score = (score > max_score ? score : max_score);
    }
    return max_score;
}

- (NSMutableArray*)nodes {
    
    if (!nodes) {
        nodes = [[NSMutableArray alloc] initWithCapacity:20];
    }
    return nodes;
}

- (void)dealloc {
    [rules release], rules = nil;
    [nodes release], nodes = nil;
    [selector release], selector = nil;
    [super dealloc];
}
@end