Put singleinflght impl. in its own file

Author: miekg

client.go

@@ -8,13 +8,10 @@ import (
 	"log"
 	"net/url"
 	"strings"
-	"sync"
 
 	"github.com/coreos/go-etcd/etcd"
 )
 
-var etcdInflight = new(etcdSingle)
-
 func NewClient(machines []string) (client *etcd.Client) {
 	// set default if not specified in env
 	if len(machines) == 1 && machines[0] == "" {
@@ -60,44 +57,6 @@ func (s *server) UpdateClient(resp *etcd.Response) {
 	s.client = c
 }
 
-type etcdCall struct {
-	wg   sync.WaitGroup
-	val  *etcd.Response
-	err  error
-	dups int
-}
-
-type etcdSingle struct {
-	sync.Mutex
-	m map[string]*etcdCall
-}
-
-func (g *etcdSingle) Do(key string, fn func() (*etcd.Response, error)) (*etcd.Response, error, bool) {
-	g.Lock()
-	if g.m == nil {
-		g.m = make(map[string]*etcdCall)
-	}
-	if c, ok := g.m[key]; ok {
-		c.dups++
-		g.Unlock()
-		c.wg.Wait()
-		return c.val, c.err, true
-	}
-	c := new(etcdCall)
-	c.wg.Add(1)
-	g.m[key] = c
-	g.Unlock()
-
-	c.val, c.err = fn()
-	c.wg.Done()
-
-	g.Lock()
-	delete(g.m, key)
-	g.Unlock()
-
-	return c.val, c.err, c.dups > 0
-}
-
 // get is a wrapper for client.Get that uses SingleInflight to suppress multiple
 // outstanding queries.
 func get(client *etcd.Client, path string, recursive bool) (*etcd.Response, error) {

dnssec.go

@@ -6,15 +6,12 @@ package main
 
 import (
 	"os"
-	"sync"
 	"time"
 
 	"github.com/miekg/dns"
 	"github.com/skynetservices/skydns/cache"
 )
 
-var inflight = new(single)
-
 // ParseKeyFile read a DNSSEC keyfile as generated by dnssec-keygen or other
 // utilities. It add ".key" for the public key and ".private" for the private key.
 func ParseKeyFile(file string) (*dns.DNSKEY, dns.PrivateKey, error) {
@@ -161,42 +158,3 @@ func rrSets(rrs []dns.RR) map[rrset][]dns.RR {
 	}
 	return nil
 }
-
-// Adapted from singleinflight.go from the original Go Code. Copyright 2013 The Go Authors.
-type call struct {
-	wg   sync.WaitGroup
-	val  *dns.RRSIG
-	err  error
-	dups int
-}
-
-type single struct {
-	sync.Mutex
-	m map[string]*call
-}
-
-func (g *single) Do(key string, fn func() (*dns.RRSIG, error)) (*dns.RRSIG, error, bool) {
-	g.Lock()
-	if g.m == nil {
-		g.m = make(map[string]*call)
-	}
-	if c, ok := g.m[key]; ok {
-		c.dups++
-		g.Unlock()
-		c.wg.Wait()
-		return c.val, c.err, true
-	}
-	c := new(call)
-	c.wg.Add(1)
-	g.m[key] = c
-	g.Unlock()
-
-	c.val, c.err = fn()
-	c.wg.Done()
-
-	g.Lock()
-	delete(g.m, key)
-	g.Unlock()
-
-	return c.val, c.err, c.dups > 0
-}

singleinflight.go

@@ -0,0 +1,94 @@
+// Copyright (c) 2013 Erik St. Martin, Brian Ketelsen. All rights reserved.
+// Use of this source code is governed by The MIT License (MIT) that can be
+// found in the LICENSE file.
+
+package main
+
+import (
+	"sync"
+
+	"github.com/coreos/go-etcd/etcd"
+	"github.com/miekg/dns"
+)
+
+var (
+	inflight     = new(single)
+	etcdInflight = new(etcdSingle)
+)
+
+// Adapted from singleinflight.go from the original Go Code. Copyright 2013 The Go Authors.
+type call struct {
+	wg   sync.WaitGroup
+	val  *dns.RRSIG
+	err  error
+	dups int
+}
+
+type single struct {
+	sync.Mutex
+	m map[string]*call
+}
+
+func (g *single) Do(key string, fn func() (*dns.RRSIG, error)) (*dns.RRSIG, error, bool) {
+	g.Lock()
+	if g.m == nil {
+		g.m = make(map[string]*call)
+	}
+	if c, ok := g.m[key]; ok {
+		c.dups++
+		g.Unlock()
+		c.wg.Wait()
+		return c.val, c.err, true
+	}
+	c := new(call)
+	c.wg.Add(1)
+	g.m[key] = c
+	g.Unlock()
+
+	c.val, c.err = fn()
+	c.wg.Done()
+
+	g.Lock()
+	delete(g.m, key)
+	g.Unlock()
+
+	return c.val, c.err, c.dups > 0
+}
+
+type etcdCall struct {
+	wg   sync.WaitGroup
+	val  *etcd.Response
+	err  error
+	dups int
+}
+
+type etcdSingle struct {
+	sync.Mutex
+	m map[string]*etcdCall
+}
+
+func (g *etcdSingle) Do(key string, fn func() (*etcd.Response, error)) (*etcd.Response, error, bool) {
+	g.Lock()
+	if g.m == nil {
+		g.m = make(map[string]*etcdCall)
+	}
+	if c, ok := g.m[key]; ok {
+		c.dups++
+		g.Unlock()
+		c.wg.Wait()
+		return c.val, c.err, true
+	}
+	c := new(etcdCall)
+	c.wg.Add(1)
+	g.m[key] = c
+	g.Unlock()
+
+	c.val, c.err = fn()
+	c.wg.Done()
+
+	g.Lock()
+	delete(g.m, key)
+	g.Unlock()
+
+	return c.val, c.err, c.dups > 0
+}