initial implementation

pkg/router/pattern.go

@@ -0,0 +1,71 @@
+package router
+
+import "strings"
+
+func splitPattern(pattern string) (method, host, path string) {
+	rest := pattern
+	if i := strings.Index(pattern, " "); i >= 0 {
+		method = pattern[:i]
+		rest = strings.TrimLeft(pattern[i+1:], " ")
+	}
+	if strings.HasPrefix(rest, "/") {
+		return method, "", rest
+	}
+	if i := strings.Index(rest, "/"); i >= 0 {
+		return method, rest[:i], rest[i:]
+	}
+	return method, rest, ""
+}
+
+func validateGroupPrefix(p string) {
+	if p == "" {
+		return
+	}
+	if strings.ContainsAny(p, " \t") {
+		panic("lightmux: group prefix must not contain whitespace (no method or host allowed): " + p)
+	}
+	if !strings.HasPrefix(p, "/") {
+		panic("lightmux: group prefix must start with '/': " + p)
+	}
+}
+
+func normalizeGroupPrefix(p string) string {
+	if p == "" {
+		return ""
+	}
+	if len(p) > 1 && strings.HasSuffix(p, "/") {
+		return p[:len(p)-1]
+	}
+	if p == "/" {
+		return ""
+	}
+	return p
+}
+
+func joinPath(prefix, sub string) string {
+	if prefix == "" {
+		return sub
+	}
+	if sub == "" {
+		return prefix
+	}
+	if sub == "/" {
+		return prefix + "/"
+	}
+	if !strings.HasPrefix(sub, "/") {
+		panic("lightmux: route path must start with '/': " + sub)
+	}
+	return prefix + sub
+}
+
+func buildPattern(method, prefix, pattern string) string {
+	m, host, path := splitPattern(pattern)
+	if method != "" {
+		m = method
+	}
+	full := host + joinPath(prefix, path)
+	if m != "" {
+		return m + " " + full
+	}
+	return full
+}