talk updates

talk/code/0/store.go

@@ -5,7 +5,6 @@ import "sync"
 type URLStore struct {
 	urls  map[string]string
 	mu    sync.RWMutex
-	count int
 }
 
 func NewURLStore() *URLStore {
@@ -28,13 +27,18 @@ func (s *URLStore) Set(key, url string) bool {
 	return true
 }
 
+func (s *URLStore) Count() int {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	return len(s.urls)
+}
+
 func (s *URLStore) Put(url string) string {
 	for {
-		key := genKey(s.count)
-		s.count++
+		key := genKey(s.Count())
 		if ok := s.Set(key, url); ok {
 			return key
 		}
 	}
-	return ""
+	panic("shouldn't get here")
 }

talk/code/1/store.go

@@ -10,7 +10,6 @@ import (
 type URLStore struct {
 	urls     map[string]string
 	mu       sync.RWMutex
-	count    int
 	file     *os.File
 }
 
@@ -22,7 +21,7 @@ func NewURLStore(filename string) *URLStore {
 	s := &URLStore{urls: make(map[string]string)}
 	f, err := os.Open(filename, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0644)
 	if err != nil {
-		log.Exit("URLStore:", err)
+		log.Fatal("URLStore:", err)
 	}
 	s.file = f
 	if err := s.load(); err != nil {
@@ -47,10 +46,15 @@ func (s *URLStore) Set(key, url string) bool {
 	return true
 }
 
+func (s *URLStore) Count() int {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	return len(s.urls)
+}
+
 func (s *URLStore) Put(url string) string {
 	for {
-		key := genKey(s.count)
-		s.count++
+		key := genKey(s.Count())
 		if ok := s.Set(key, url); ok {
 			if err := s.save(key, url); err != nil {
 				log.Println("URLStore:", err)

talk/code/2/main.go

@@ -1,16 +1,25 @@
 package main
 
 import (
+	"flag"
 	"fmt"
 	"http"
 )
 
-var store = NewURLStore("store.gob")
+var (
+	listenAddr = flag.String("http", ":8080", "http listen address")
+	dataFile   = flag.String("file", "store.gob", "data store file name")
+	hostname   = flag.String("host", "localhost:8080", "http host name")
+)
+
+var store *URLStore
 
 func main() {
+	flag.Parse()
+	store = NewURLStore(*dataFile)
 	http.HandleFunc("/", Redirect)
 	http.HandleFunc("/add", Add)
-	http.ListenAndServe(":8080", nil)
+	http.ListenAndServe(*listenAddr, nil)
 }
 
 func Redirect(w http.ResponseWriter, r *http.Request) {
@@ -30,7 +39,7 @@ func Add(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	key := store.Put(url)
-	fmt.Fprintf(w, "http://localhost:8080/%s", key)
+	fmt.Fprintf(w, "http://%s/%s", *hostname, key)
 }
 
 const AddForm = `

talk/code/2/store.go

@@ -12,7 +12,6 @@ const saveQueueLength = 1000
 type URLStore struct {
 	urls  map[string]string
 	mu    sync.RWMutex
-	count int
 	save  chan record
 }
 
@@ -48,10 +47,15 @@ func (s *URLStore) Set(key, url string) bool {
 	return true
 }
 
+func (s *URLStore) Count() int {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	return len(s.urls)
+}
+
 func (s *URLStore) Put(url string) string {
 	for {
-		key := genKey(s.count)
-		s.count++
+		key := genKey(s.Count())
 		if ok := s.Set(key, url); ok {
 			s.save <- record{key, url}
 			return key
@@ -82,7 +86,7 @@ func (s *URLStore) load(filename string) os.Error {
 func (s *URLStore) saveLoop(filename string) {
 	f, err := os.Open(filename, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0644)
 	if err != nil {
-		log.Exit("URLStore:", err)
+		log.Fatal("URLStore:", err)
 	}
 	e := gob.NewEncoder(f)
 	for {

talk/code/3/store.go

@@ -18,7 +18,6 @@ type Store interface {
 type URLStore struct {
 	urls  map[string]string
 	mu    sync.RWMutex
-	count int
 	save  chan record
 }
 
@@ -58,10 +57,15 @@ func (s *URLStore) Set(key, url *string) os.Error {
 	return nil
 }
 
+func (s *URLStore) Count() int {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	return len(s.urls)
+}
+
 func (s *URLStore) Put(url, key *string) os.Error {
 	for {
-		*key = genKey(s.count)
-		s.count++
+		*key = genKey(s.Count())
 		if err := s.Set(key, url); err == nil {
 			break
 		}
@@ -94,7 +98,7 @@ func (s *URLStore) load(filename string) os.Error {
 func (s *URLStore) saveLoop(filename string) {
 	f, err := os.Open(filename, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0644)
 	if err != nil {
-		log.Exit("URLStore:", err)
+		log.Fatal("URLStore:", err)
 	}
 	e := gob.NewEncoder(f)
 	for {