From 92ae1d67265b4cf52d659a340435398e8da2ad05 Mon Sep 17 00:00:00 2001
From: Dj Gilcrease <digitalxero@gmail.com>
Date: Thu, 9 Jul 2015 11:46:53 -0700
Subject: [PATCH] Update the walk method to walk matchers so it walks the full
 list of routers and child routers

---
 mux.go      | 47 +++++++++++++++++++++++++++++++++
 mux_test.go | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 122 insertions(+)

diff --git a/mux.go b/mux.go
index af31d23..ec1ef37 100644
--- a/mux.go
+++ b/mux.go
@@ -5,6 +5,7 @@
 package mux
 
 import (
+	"errors"
 	"fmt"
 	"net/http"
 	"path"
@@ -237,6 +238,52 @@ func (r *Router) BuildVarsFunc(f BuildVarsFunc) *Route {
 	return r.NewRoute().BuildVarsFunc(f)
 }
 
+// Walk walks the router and all its sub-routers, calling walkFn for each route
+// in the tree. The routes are walked in the order they were added. Sub-routers
+// are explored depth-first.
+func (r *Router) Walk(walkFn WalkFunc) error {
+	return r.walk(walkFn, []*Route{})
+}
+
+// SkipRouter is used as a return value from WalkFuncs to indicate that the
+// router that walk is about to descend down to should be skipped.
+var SkipRouter = errors.New("skip this router")
+
+// WalkFunc is the type of the function called for each route visited by Walk.
+// At every invocation, it is given the current route, and the current router,
+// and a list of ancestor routes that lead to the current route.
+type WalkFunc func(route *Route, router *Router, ancestors []*Route) error
+
+func (r *Router) walk(walkFn WalkFunc, ancestors []*Route) error {
+	for _, t := range r.routes {
+		if t.regexp == nil || t.regexp.path == nil || t.regexp.path.template == "" {
+			continue
+		}
+
+		err := walkFn(t, r, ancestors)
+		if err == SkipRouter {
+			continue
+		}
+		for _, sr := range t.matchers {
+			if h, ok := sr.(*Router); ok {
+				err := h.walk(walkFn, ancestors)
+				if err != nil {
+					return err
+				}
+			}
+		}
+		if h, ok := t.handler.(*Router); ok {
+			ancestors = append(ancestors, t)
+			err := h.walk(walkFn, ancestors)
+			if err != nil {
+				return err
+			}
+			ancestors = ancestors[:len(ancestors)-1]
+		}
+	}
+	return nil
+}
+
 // ----------------------------------------------------------------------------
 // Context
 // ----------------------------------------------------------------------------
diff --git a/mux_test.go b/mux_test.go
index 8118aab..d8dc551 100644
--- a/mux_test.go
+++ b/mux_test.go
@@ -837,6 +837,81 @@ func TestStrictSlash(t *testing.T) {
 	}
 }
 
+func TestWalkSingleDepth(t *testing.T) {
+	r0 := NewRouter()
+	r1 := NewRouter()
+	r2 := NewRouter()
+
+	r0.Path("/g")
+	r0.Path("/o")
+	r0.Path("/d").Handler(r1)
+	r0.Path("/r").Handler(r2)
+	r0.Path("/a")
+
+	r1.Path("/z")
+	r1.Path("/i")
+	r1.Path("/l")
+	r1.Path("/l")
+
+	r2.Path("/i")
+	r2.Path("/l")
+	r2.Path("/l")
+
+	paths := []string{"g", "o", "r", "i", "l", "l", "a"}
+	depths := []int{0, 0, 0, 1, 1, 1, 0}
+	i := 0
+	err := r0.Walk(func(route *Route, router *Router, ancestors []*Route) error {
+		matcher := route.matchers[0].(*routeRegexp)
+		if matcher.template == "/d" {
+			return SkipRouter
+		}
+		if len(ancestors) != depths[i] {
+			t.Errorf(`Expected depth of %d at i = %d; got "%s"`, depths[i], i, len(ancestors))
+		}
+		if matcher.template != "/"+paths[i] {
+			t.Errorf(`Expected "/%s" at i = %d; got "%s"`, paths[i], i, matcher.template)
+		}
+		i++
+		return nil
+	})
+	if err != nil {
+		panic(err)
+	}
+	if i != len(paths) {
+		t.Errorf("Expected %d routes, found %d", len(paths), i)
+	}
+}
+
+func TestWalkNested(t *testing.T) {
+	router := NewRouter()
+
+	g := router.Path("/g").Subrouter()
+	o := g.PathPrefix("/o").Subrouter()
+	r := o.PathPrefix("/r").Subrouter()
+	i := r.PathPrefix("/i").Subrouter()
+	l1 := i.PathPrefix("/l").Subrouter()
+	l2 := l1.PathPrefix("/l").Subrouter()
+	l2.Path("/a")
+
+	paths := []string{"/g", "/g/o", "/g/o/r", "/g/o/r/i", "/g/o/r/i/l", "/g/o/r/i/l/l", "/g/o/r/i/l/l/a"}
+	idx := 0
+	err := router.Walk(func(route *Route, router *Router, ancestors []*Route) error {
+		path := paths[idx]
+		tpl := route.regexp.path.template
+		if tpl != path {
+			t.Errorf(`Expected %s got %s`, path, tpl)
+		}
+		idx++
+		return nil
+	})
+	if err != nil {
+		panic(err)
+	}
+	if idx != len(paths) {
+		t.Errorf("Expected %d routes, found %d", len(paths), idx)
+	}
+}
+
 // ----------------------------------------------------------------------------
 // Helpers
 // ----------------------------------------------------------------------------