(elementMatchers, setMatchers)
| 1941 | //返回的是一个终极匹配器superMatcher |
| 1942 | //生成用于匹配单个选择器群组的函数 |
| 1943 | function matcherFromGroupMatchers(elementMatchers, setMatchers) { |
| 1944 | |
| 1945 | // A counter to specify which element is currently being matched |
| 1946 | // 用计数器来指定当前哪个元素正在匹配 |
| 1947 | var matcherCachedRuns = 0, |
| 1948 | bySet = setMatchers.length > 0, |
| 1949 | byElement = elementMatchers.length > 0, |
| 1950 | |
| 1951 | superMatcher = function(seed, context, xml, results, expandContext) { |
| 1952 | var elem, j, matcher, |
| 1953 | setMatched = [], |
| 1954 | matchedCount = 0, |
| 1955 | i = "0", |
| 1956 | unmatched = seed && [], |
| 1957 | outermost = expandContext != null, |
| 1958 | contextBackup = outermostContext, |
| 1959 | |
| 1960 | //这一步很关键！ |
| 1961 | //如果说有初始集合seed，那用它 |
| 1962 | //如果没有，那只能把整个DOM树节点取出来过滤了，可以看出选择器最右边应该写一个 |
| 1963 | // We must always have either seed elements or context |
| 1964 | elems = seed || byElement && Expr.find["TAG"]("*", expandContext && context.parentNode || context), |
| 1965 | // Use integer dirruns iff this is the outermost matcher |
| 1966 | dirrunsUnique = (dirruns += contextBackup == null ? 1 : Math.random() || 0.1), |
| 1967 | len = elems.length; |
| 1968 | |
| 1969 | if (outermost) { |
| 1970 | outermostContext = context !== document && context; |
| 1971 | cachedruns = matcherCachedRuns; |
| 1972 | } |
| 1973 | |
| 1974 | //好，开始过滤这个elems集合了！ |
| 1975 | // Add elements passing elementMatchers directly to results |
| 1976 | // Keep `i` a string if there are no elements so `matchedCount` will be "00" below |
| 1977 | // Support: IE<9, Safari |
| 1978 | // Tolerate NodeList properties (IE: "length"; Safari: <number>) matching elements by id |
| 1979 | for (; i !== len && (elem = elems[i]) != null; i++) { |
| 1980 | if (byElement && elem) { |
| 1981 | j = 0; |
| 1982 | |
| 1983 | //把所有的过滤器拿出来 |
| 1984 | //这里的每个匹配器都是上边提到的终极匹配器，既然是终极匹配器，那为什么会有多个呢？ |
| 1985 | //因为：div, p实际上是需要两个终极匹配器的（逗号分隔开表示有两个选择器了），:) |
| 1986 | while ((matcher = elementMatchers[j++])) { |
| 1987 | //过滤这个集合的元素elem，如果符合匹配器的规则，那么就添加到结果集里边去 |
| 1988 | if (matcher(elem, context, xml)) { |
| 1989 | results.push(elem); |
| 1990 | break; |
| 1991 | } |
| 1992 | } |
| 1993 | if (outermost) { |
| 1994 | dirruns = dirrunsUnique; |
| 1995 | cachedruns = ++matcherCachedRuns; |
| 1996 | } |
| 1997 | } |
| 1998 | |
| 1999 | // Track unmatched elements for set filters |
| 2000 | if (bySet) { |
no test coverage detected