From bef622222da715561fb3ac963719a08ca2caf696 Mon Sep 17 00:00:00 2001
From: Brian Tiger Chow <brian.holderchow@gmail.com>
Date: Tue, 16 Dec 2014 22:46:53 -0800
Subject: [PATCH] refactor: wantlist splits into WL and ThreadSafe WL

bitswap keeps the threadsafe version. observing the ledger shows that it
doesn't need it anymore (ledgermanager is protected and safe).

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>
---
 exchange/bitswap/bitswap.go           |  8 +--
 exchange/bitswap/wantlist/wantlist.go | 88 ++++++++++++++++++++-------
 2 files changed, 71 insertions(+), 25 deletions(-)

diff --git a/exchange/bitswap/bitswap.go b/exchange/bitswap/bitswap.go
index d9b3c52ef..473bf117e 100644
--- a/exchange/bitswap/bitswap.go
+++ b/exchange/bitswap/bitswap.go
@@ -15,7 +15,7 @@ import (
 	bsnet "github.com/jbenet/go-ipfs/exchange/bitswap/network"
 	notifications "github.com/jbenet/go-ipfs/exchange/bitswap/notifications"
 	strategy "github.com/jbenet/go-ipfs/exchange/bitswap/strategy"
-	wl "github.com/jbenet/go-ipfs/exchange/bitswap/wantlist"
+	wantlist "github.com/jbenet/go-ipfs/exchange/bitswap/wantlist"
 	peer "github.com/jbenet/go-ipfs/peer"
 	u "github.com/jbenet/go-ipfs/util"
 	eventlog "github.com/jbenet/go-ipfs/util/eventlog"
@@ -59,7 +59,7 @@ func New(parent context.Context, p peer.Peer, network bsnet.BitSwapNetwork, rout
 		ledgermanager: strategy.NewLedgerManager(ctx, bstore),
 		routing:       routing,
 		sender:        network,
-		wantlist:      wl.New(),
+		wantlist:      wantlist.NewThreadSafe(),
 		batchRequests: make(chan []u.Key, 32),
 	}
 	network.SetDelegate(bs)
@@ -95,7 +95,7 @@ type bitswap struct {
 
 	ledgermanager *strategy.LedgerManager
 
-	wantlist *wl.Wantlist
+	wantlist *wantlist.ThreadSafe
 
 	// cancelFunc signals cancellation to the bitswap event loop
 	cancelFunc func()
@@ -203,7 +203,7 @@ func (bs *bitswap) sendWantListTo(ctx context.Context, peers <-chan peer.Peer) e
 	return nil
 }
 
-func (bs *bitswap) sendWantlistToProviders(ctx context.Context, wantlist *wl.Wantlist) {
+func (bs *bitswap) sendWantlistToProviders(ctx context.Context, wantlist *wantlist.ThreadSafe) {
 	ctx, cancel := context.WithCancel(ctx)
 	defer cancel()
 
diff --git a/exchange/bitswap/wantlist/wantlist.go b/exchange/bitswap/wantlist/wantlist.go
index 2c50daa49..6ef018668 100644
--- a/exchange/bitswap/wantlist/wantlist.go
+++ b/exchange/bitswap/wantlist/wantlist.go
@@ -6,25 +6,86 @@ import (
 	"sync"
 )
 
+type ThreadSafe struct {
+	lk sync.RWMutex
+	Wantlist
+}
+
+// not threadsafe
 type Wantlist struct {
-	lk  sync.RWMutex
 	set map[u.Key]*Entry
 }
 
+type Entry struct {
+	Key      u.Key
+	Priority int
+}
+
+type entrySlice []*Entry
+
+func (es entrySlice) Len() int           { return len(es) }
+func (es entrySlice) Swap(i, j int)      { es[i], es[j] = es[j], es[i] }
+func (es entrySlice) Less(i, j int) bool { return es[i].Priority > es[j].Priority }
+
+func NewThreadSafe() *ThreadSafe {
+	return &ThreadSafe{
+		Wantlist: *New(),
+	}
+}
+
 func New() *Wantlist {
 	return &Wantlist{
 		set: make(map[u.Key]*Entry),
 	}
 }
 
-type Entry struct {
-	Key      u.Key
-	Priority int
+func (w *ThreadSafe) Add(k u.Key, priority int) {
+	// TODO rm defer for perf
+	w.lk.Lock()
+	defer w.lk.Unlock()
+	w.Wantlist.Add(k, priority)
+}
+
+func (w *ThreadSafe) Remove(k u.Key) {
+	// TODO rm defer for perf
+	w.lk.Lock()
+	defer w.lk.Unlock()
+	w.Wantlist.Remove(k)
+}
+
+func (w *ThreadSafe) Contains(k u.Key) bool {
+	// TODO rm defer for perf
+	w.lk.RLock()
+	defer w.lk.RUnlock()
+	return w.Wantlist.Contains(k)
+}
+
+func (w *ThreadSafe) Entries() []*Entry {
+	w.lk.RLock()
+	defer w.lk.RUnlock()
+	var es entrySlice
+	for _, e := range w.set {
+		es = append(es, e)
+	}
+	// TODO rename SortedEntries (state that they're sorted so callers know
+	// they're paying an expense)
+	sort.Sort(es)
+	return es
+}
+
+func (w *ThreadSafe) SortedEntries() []*Entry {
+	w.lk.RLock()
+	defer w.lk.RUnlock()
+	var es entrySlice
+
+	for _, e := range w.set {
+		es = append(es, e)
+	}
+	sort.Sort(es)
+	return es
 }
 
 func (w *Wantlist) Add(k u.Key, priority int) {
-	w.lk.Lock()
-	defer w.lk.Unlock()
 	if _, ok := w.set[k]; ok {
 		return
 	}
@@ -35,28 +96,15 @@ func (w *Wantlist) Add(k u.Key, priority int) {
 }
 
 func (w *Wantlist) Remove(k u.Key) {
-	w.lk.Lock()
-	defer w.lk.Unlock()
 	delete(w.set, k)
 }
 
 func (w *Wantlist) Contains(k u.Key) bool {
-	w.lk.RLock()
-	defer w.lk.RUnlock()
 	_, ok := w.set[k]
 	return ok
 }
 
-type entrySlice []*Entry
-
-func (es entrySlice) Len() int           { return len(es) }
-func (es entrySlice) Swap(i, j int)      { es[i], es[j] = es[j], es[i] }
-func (es entrySlice) Less(i, j int) bool { return es[i].Priority > es[j].Priority }
-
 func (w *Wantlist) Entries() []*Entry {
-	w.lk.RLock()
-	defer w.lk.RUnlock()
-
 	var es entrySlice
 
 	for _, e := range w.set {
@@ -67,8 +115,6 @@ func (w *Wantlist) Entries() []*Entry {
 }
 
 func (w *Wantlist) SortedEntries() []*Entry {
-	w.lk.RLock()
-	defer w.lk.RUnlock()
 	var es entrySlice
 
 	for _, e := range w.set {