reorganizing content-related packages

src/content/htmlutil/query.go

@@ -0,0 +1,76 @@
+package htmlutil
+
+import (
+	"regexp"
+	"strings"
+
+	"golang.org/x/net/html"
+)
+
+var nodeNameRegex = regexp.MustCompile(`\w+|\*`)
+
+func FindNodes(node *html.Node, match func(*html.Node) bool) []*html.Node {
+	nodes := make([]*html.Node, 0)
+
+	queue := make([]*html.Node, 0)
+	queue = append(queue, node)
+	for len(queue) > 0 {
+		var n *html.Node
+		n, queue = queue[0], queue[1:]
+		if match(n) {
+			nodes = append(nodes, n)
+		}
+		for c := n.FirstChild; c != nil; c = c.NextSibling {
+			queue = append(queue, c)
+		}
+	}
+	return nodes
+}
+
+func Query(node *html.Node, sel string) []*html.Node {
+	matcher := NewMatcher(sel)
+	return FindNodes(node, matcher.Match)
+}
+
+func NewMatcher(sel string) Matcher {
+	multi := MultiMatch{}
+	parts := strings.Split(sel, ",")
+	for _, part := range parts {
+		part := strings.TrimSpace(part)
+		if nodeNameRegex.MatchString(part) {
+			multi.Add(ElementMatch{Name: part})
+		} else {
+			panic("unsupported selector: " + part)
+		}
+	}
+	return multi
+}
+
+type Matcher interface {
+	Match(*html.Node) bool
+}
+
+type ElementMatch struct {
+	Name string
+}
+
+func (m ElementMatch) Match(n *html.Node) bool {
+	return n.Type == html.ElementNode && (n.Data == m.Name || m.Name == "*")
+}
+
+type MultiMatch struct {
+	matchers []Matcher
+}
+
+func (m *MultiMatch) Add(matcher Matcher) {
+	m.matchers = append(m.matchers, matcher)
+}
+
+func (m MultiMatch) Match(n *html.Node) bool {
+	for _, matcher := range m.matchers {
+		if matcher.Match(n) {
+			return true
+		}
+	}
+	return false
+}