From 468eefee579b7006e805c39093be6d5f7793044d Mon Sep 17 00:00:00 2001
From: Leo Balduf <balduf@hm.edu>
Date: Sun, 1 May 2016 17:56:07 -0400
Subject: [PATCH 1/3] store: add ErrResourceDoesNotExist and update memory
 implementation

---
 server/store/ip_store.go                 | 20 ++++++++++++------
 server/store/memory/ip_store.go          | 27 ++++++++++++++++--------
 server/store/memory/ip_store_test.go     |  3 ++-
 server/store/memory/peer_store.go        | 20 ++++++++++++++----
 server/store/memory/string_store.go      |  4 ++++
 server/store/memory/string_store_test.go |  8 ++++---
 server/store/peer_store.go               | 14 ++++++++----
 server/store/store.go                    |  4 ++++
 server/store/string_store.go             |  8 +++++++
 tracker/tracker.go                       |  2 +-
 10 files changed, 81 insertions(+), 29 deletions(-)

diff --git a/server/store/ip_store.go b/server/store/ip_store.go
index 3fea3a6..e02afb5 100644
--- a/server/store/ip_store.go
+++ b/server/store/ip_store.go
@@ -21,30 +21,36 @@ type IPStore interface {
 	AddNetwork(network string) error
 
 	// HasIP returns whether the given IP address is contained in the IPStore
-	// or belong to any of the stored networks.
+	// or belongs to any of the stored networks.
 	HasIP(ip net.IP) (bool, error)
 
-	// HasAnyIP returns whether any of the given IP addresses are contained in
-	// the IPStore or belong to any of the stored networks.
+	// HasAnyIP returns whether any of the given IP addresses are contained
+	// in the IPStore or belongs to any of the stored networks.
 	HasAnyIP(ips []net.IP) (bool, error)
 
-	// HassAllIPs returns whether all of the given IP addresses are contained in
-	// the IPStore or belong to any of the stored networks.
+	// HassAllIPs returns whether all of the given IP addresses are
+	// contained in the IPStore or belongs to any of the stored networks.
 	HasAllIPs(ips []net.IP) (bool, error)
 
 	// RemoveIP removes a single IP address from the IPStore.
 	//
 	// This wil not remove the given address from any networks it belongs to
 	// that are stored in the IPStore.
+	//
+	// Returns ErrResourceDoesNotExist if the given IP address is not
+	// contained in the store.
 	RemoveIP(ip net.IP) error
 
-	// RemoveNetwork removes a range of IP addresses that was previously added
-	// through AddNetwork.
+	// RemoveNetwork removes a range of IP addresses that was previously
+	// added through AddNetwork.
 	//
 	// The given network must not, as a string, match the previously added
 	// network, but rather denote the same network, e.g. if the network
 	// 192.168.22.255/24 was added, removing the network 192.168.22.123/24
 	// will succeed.
+	//
+	// Returns ErrResourceDoesNotExist if the given network is not
+	// contained in the store.
 	RemoveNetwork(network string) error
 }
 
diff --git a/server/store/memory/ip_store.go b/server/store/memory/ip_store.go
index 77b0506..dc2f4b8 100644
--- a/server/store/memory/ip_store.go
+++ b/server/store/memory/ip_store.go
@@ -57,14 +57,14 @@ func key(ip net.IP) [16]byte {
 }
 
 func (s *ipStore) AddNetwork(network string) error {
-	s.Lock()
-	defer s.Unlock()
-
 	key, length, err := netmatch.ParseNetwork(network)
 	if err != nil {
 		return err
 	}
 
+	s.Lock()
+	defer s.Unlock()
+
 	return s.networks.Add(key, length)
 }
 
@@ -78,9 +78,9 @@ func (s *ipStore) AddIP(ip net.IP) error {
 }
 
 func (s *ipStore) HasIP(ip net.IP) (bool, error) {
+	key := key(ip)
 	s.RLock()
 	defer s.RUnlock()
-	key := key(ip)
 
 	_, ok := s.ips[key]
 	if ok {
@@ -138,22 +138,31 @@ func (s *ipStore) HasAllIPs(ips []net.IP) (bool, error) {
 }
 
 func (s *ipStore) RemoveIP(ip net.IP) error {
+	key := key(ip)
 	s.Lock()
 	defer s.Unlock()
 
-	delete(s.ips, key(ip))
+	if _, ok := s.ips[key]; !ok {
+		return store.ErrResourceDoesNotExist
+	}
+
+	delete(s.ips, key)
 
 	return nil
 }
 
 func (s *ipStore) RemoveNetwork(network string) error {
-	s.Lock()
-	defer s.Unlock()
-
 	key, length, err := netmatch.ParseNetwork(network)
 	if err != nil {
 		return err
 	}
 
-	return s.networks.Remove(key, length)
+	s.Lock()
+	defer s.Unlock()
+
+	err = s.networks.Remove(key, length)
+	if err != nil && err == netmatch.ErrNotContained {
+		return store.ErrResourceDoesNotExist
+	}
+	return err
 }
diff --git a/server/store/memory/ip_store_test.go b/server/store/memory/ip_store_test.go
index e6c83c2..80f7610 100644
--- a/server/store/memory/ip_store_test.go
+++ b/server/store/memory/ip_store_test.go
@@ -9,6 +9,7 @@ import (
 	"testing"
 
 	"github.com/chihaya/chihaya/server/store"
+
 	"github.com/stretchr/testify/assert"
 )
 
@@ -64,7 +65,7 @@ func TestIPStore(t *testing.T) {
 
 	// check removes
 	err = s.RemoveIP(v6)
-	assert.Nil(t, err)
+	assert.NotNil(t, err)
 
 	err = s.RemoveIP(v4s)
 	assert.Nil(t, err)
diff --git a/server/store/memory/peer_store.go b/server/store/memory/peer_store.go
index 6638940..ef5257f 100644
--- a/server/store/memory/peer_store.go
+++ b/server/store/memory/peer_store.go
@@ -119,10 +119,16 @@ func (s *peerStore) DeleteSeeder(infoHash chihaya.InfoHash, p chihaya.Peer) erro
 	defer shard.Unlock()
 
 	if shard.peers[key] == nil {
-		return nil
+		return store.ErrResourceDoesNotExist
 	}
 
-	delete(shard.peers[key], peerKey(p))
+	pk := peerKey(p)
+
+	if _, ok := shard.peers[key][pk]; !ok {
+		return store.ErrResourceDoesNotExist
+	}
+
+	delete(shard.peers[key], pk)
 
 	if len(shard.peers[key]) == 0 {
 		delete(shard.peers, key)
@@ -156,10 +162,16 @@ func (s *peerStore) DeleteLeecher(infoHash chihaya.InfoHash, p chihaya.Peer) err
 	defer shard.Unlock()
 
 	if shard.peers[key] == nil {
-		return nil
+		return store.ErrResourceDoesNotExist
 	}
 
-	delete(shard.peers[key], peerKey(p))
+	pk := peerKey(p)
+
+	if _, ok := shard.peers[key][pk]; !ok {
+		return store.ErrResourceDoesNotExist
+	}
+
+	delete(shard.peers[key], pk)
 
 	if len(shard.peers[key]) == 0 {
 		delete(shard.peers, key)
diff --git a/server/store/memory/string_store.go b/server/store/memory/string_store.go
index 2fbba18..85cc4d4 100644
--- a/server/store/memory/string_store.go
+++ b/server/store/memory/string_store.go
@@ -51,6 +51,10 @@ func (ss *stringStore) RemoveString(s string) error {
 	ss.Lock()
 	defer ss.Unlock()
 
+	if _, ok := ss.strings[s]; !ok {
+		return store.ErrResourceDoesNotExist
+	}
+
 	delete(ss.strings, s)
 
 	return nil
diff --git a/server/store/memory/string_store_test.go b/server/store/memory/string_store_test.go
index 39fe802..32618e4 100644
--- a/server/store/memory/string_store_test.go
+++ b/server/store/memory/string_store_test.go
@@ -5,9 +5,11 @@
 package memory
 
 import (
-	"github.com/chihaya/chihaya/server/store"
-	"github.com/stretchr/testify/assert"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/chihaya/chihaya/server/store"
 )
 
 var (
@@ -30,7 +32,7 @@ func TestStringStore(t *testing.T) {
 	assert.False(t, has)
 
 	err = ss.RemoveString(s1)
-	assert.Nil(t, err)
+	assert.NotNil(t, err)
 
 	err = ss.PutString(s1)
 	assert.Nil(t, err)
diff --git a/server/store/peer_store.go b/server/store/peer_store.go
index 74289d0..1cb88b5 100644
--- a/server/store/peer_store.go
+++ b/server/store/peer_store.go
@@ -18,11 +18,17 @@ type PeerStore interface {
 	// PutSeeder adds a seeder for the infoHash to the PeerStore.
 	PutSeeder(infoHash chihaya.InfoHash, p chihaya.Peer) error
 	// DeleteSeeder removes a seeder for the infoHash from the PeerStore.
+	//
+	// Returns ErrResourceDoesNotExist if the infoHash or peer does not
+	// exist.
 	DeleteSeeder(infoHash chihaya.InfoHash, p chihaya.Peer) error
 
 	// PutLeecher adds a leecher for the infoHash to the PeerStore.
 	PutLeecher(infoHash chihaya.InfoHash, p chihaya.Peer) error
 	// DeleteLeecher removes a leecher for the infoHash from the PeerStore.
+	//
+	// Returns ErrResourceDoesNotExist if the infoHash or peer does not
+	// exist.
 	DeleteLeecher(infoHash chihaya.InfoHash, p chihaya.Peer) error
 
 	// GraduateLeecher promotes a peer from a leecher to a seeder for the
@@ -32,11 +38,11 @@ type PeerStore interface {
 	// announce.
 	//
 	// If seeder is true then the peers returned will only be leechers, the
-	// ammount of leechers returned will be the smaller value of numWant or the
-	// available leechers.
+	// ammount of leechers returned will be the smaller value of numWant or
+	// the available leechers.
 	// If it is false then seeders will be returned up until numWant or the
-	// available seeders, whichever is smaller. If the available seeders is less
-	// than numWant then peers are returned until numWant or they run out.
+	// available seeders, whichever is smaller. If the available seeders is
+	// less than numWant then peers are returned until numWant or they run out.
 	AnnouncePeers(infoHash chihaya.InfoHash, seeder bool, numWant int, peer4, peer6 chihaya.Peer) (peers, peers6 []chihaya.Peer, err error)
 	// CollectGarbage deletes peers from the peerStore which are older than the
 	// cutoff time.
diff --git a/server/store/store.go b/server/store/store.go
index ff8a811..4625078 100644
--- a/server/store/store.go
+++ b/server/store/store.go
@@ -23,6 +23,10 @@ func init() {
 	server.Register("store", constructor)
 }
 
+// ErrResourceDoesNotExist is the error returned by all delete methods in the
+// store if the requested resource does not exist.
+var ErrResourceDoesNotExist = errors.New("resource does not exist")
+
 func constructor(srvcfg *chihaya.ServerConfig, tkr *tracker.Tracker) (server.Server, error) {
 	if theStore == nil {
 		cfg, err := newConfig(srvcfg)
diff --git a/server/store/string_store.go b/server/store/string_store.go
index 8620053..cfaea49 100644
--- a/server/store/string_store.go
+++ b/server/store/string_store.go
@@ -10,8 +10,16 @@ var stringStoreDrivers = make(map[string]StringStoreDriver)
 
 // StringStore represents an interface for manipulating strings.
 type StringStore interface {
+	// PutString adds the given string to the StringStore.
 	PutString(s string) error
+
+	// HasString returns whether or not the StringStore contains the given
+	// string.
 	HasString(s string) (bool, error)
+
+	// RemoveString removes the string from the string store.
+	// Returns ErrResourceDoesNotExist if the given string is not contained
+	// in the store.
 	RemoveString(s string) error
 }
 
diff --git a/tracker/tracker.go b/tracker/tracker.go
index c3406c9..a0b8391 100644
--- a/tracker/tracker.go
+++ b/tracker/tracker.go
@@ -8,8 +8,8 @@ package tracker
 
 import (
 	"errors"
-
 	"fmt"
+
 	"github.com/chihaya/chihaya"
 )
 

From 9f229c4ab6c55cb6d34558638e38df159eb62ff3 Mon Sep 17 00:00:00 2001
From: Leo Balduf <balduf@hm.edu>
Date: Mon, 18 Apr 2016 15:49:36 -0400
Subject: [PATCH 2/3] add helper methods to get IPv4 and IPv6 peer

---
 chihaya.go                                   | 22 ++++++++++++++++++++
 server/store/middleware/response/response.go |  6 ++----
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/chihaya.go b/chihaya.go
index 8a7386b..f8e765e 100644
--- a/chihaya.go
+++ b/chihaya.go
@@ -34,6 +34,28 @@ type AnnounceRequest struct {
 	Params Params
 }
 
+// Peer4 returns a Peer using the IPv4 endpoint of the Announce.
+// Note that, if the Announce does not contain an IPv4 address, the IP field of
+// the returned Peer can be nil.
+func (r *AnnounceRequest) Peer4() Peer {
+	return Peer{
+		IP:   r.IPv4,
+		Port: r.Port,
+		ID:   r.PeerID,
+	}
+}
+
+// Peer6 returns a Peer using the IPv6 endpoint of the Announce.
+// Note that, if the Announce does not contain an IPv6 address, the IP field of
+// the returned Peer can be nil.
+func (r *AnnounceRequest) Peer6() Peer {
+	return Peer{
+		IP:   r.IPv6,
+		Port: r.Port,
+		ID:   r.PeerID,
+	}
+}
+
 // AnnounceResponse represents the parameters used to create an announce
 // response.
 type AnnounceResponse struct {
diff --git a/server/store/middleware/response/response.go b/server/store/middleware/response/response.go
index 1970667..72d8225 100644
--- a/server/store/middleware/response/response.go
+++ b/server/store/middleware/response/response.go
@@ -27,16 +27,14 @@ func (f FailedToRetrievePeers) Error() string { return string(f) }
 func responseAnnounceClient(next tracker.AnnounceHandler) tracker.AnnounceHandler {
 	return func(cfg *chihaya.TrackerConfig, req *chihaya.AnnounceRequest, resp *chihaya.AnnounceResponse) (err error) {
 		storage := store.MustGetStore()
-		peer4 := chihaya.Peer{ID: req.PeerID, IP: req.IPv4, Port: req.Port}
-		peer6 := chihaya.Peer{ID: req.PeerID, IP: req.IPv6, Port: req.Port}
 
 		resp.MinInterval = cfg.MinAnnounceInterval
 		resp.Compact = req.Compact
 		resp.Complete = int32(storage.NumSeeders(req.InfoHash))
 		resp.Incomplete = int32(storage.NumLeechers(req.InfoHash))
-		resp.IPv4Peers, resp.IPv6Peers, err = storage.AnnouncePeers(req.InfoHash, req.Left == 0, int(req.NumWant), peer4, peer6)
+		resp.IPv4Peers, resp.IPv6Peers, err = storage.AnnouncePeers(req.InfoHash, req.Left == 0, int(req.NumWant), req.Peer4(), req.Peer6())
 		if err != nil {
-			return err.(FailedToRetrievePeers)
+			return FailedToRetrievePeers(err.Error())
 		}
 
 		return next(cfg, req, resp)

From aaf9978df376b3754a9c824f795349f8d89e1148 Mon Sep 17 00:00:00 2001
From: Leo Balduf <balduf@hm.edu>
Date: Mon, 18 Apr 2016 15:49:55 -0400
Subject: [PATCH 3/3] middleware: add swarm interaction

---
 cmd/chihaya/main.go                     |  1 +
 server/store/middleware/swarm/README.md | 12 ++++
 server/store/middleware/swarm/swarm.go  | 75 +++++++++++++++++++++++++
 server/store/peer_store.go              |  4 ++
 4 files changed, 92 insertions(+)
 create mode 100644 server/store/middleware/swarm/README.md
 create mode 100644 server/store/middleware/swarm/swarm.go

diff --git a/cmd/chihaya/main.go b/cmd/chihaya/main.go
index 4796d54..30e74f6 100644
--- a/cmd/chihaya/main.go
+++ b/cmd/chihaya/main.go
@@ -28,6 +28,7 @@ import (
 	_ "github.com/chihaya/chihaya/server/store/middleware/infohash"
 	_ "github.com/chihaya/chihaya/server/store/middleware/ip"
 	_ "github.com/chihaya/chihaya/server/store/middleware/response"
+	_ "github.com/chihaya/chihaya/server/store/middleware/swarm"
 )
 
 var configPath string
diff --git a/server/store/middleware/swarm/README.md b/server/store/middleware/swarm/README.md
new file mode 100644
index 0000000..60444e7
--- /dev/null
+++ b/server/store/middleware/swarm/README.md
@@ -0,0 +1,12 @@
+## Swarm Interaction Middleware
+
+This package provides the announce middleware that modifies peer data stored in the `store` package.
+
+### `store_swarm_interaction`
+
+The `store_swarm_interaction` middleware updates the data stored in the `peerStore` based on the announce.
+
+### Important things to notice
+
+It is recommended to have this middleware run before the `store_response` middleware.
+The `store_response` middleware assumes the store to be already updated by the announce.
\ No newline at end of file
diff --git a/server/store/middleware/swarm/swarm.go b/server/store/middleware/swarm/swarm.go
new file mode 100644
index 0000000..87ff15b
--- /dev/null
+++ b/server/store/middleware/swarm/swarm.go
@@ -0,0 +1,75 @@
+// Copyright 2016 The Chihaya Authors. All rights reserved.
+// Use of this source code is governed by the BSD 2-Clause license,
+// which can be found in the LICENSE file.
+
+package response
+
+import (
+	"github.com/chihaya/chihaya"
+	"github.com/chihaya/chihaya/pkg/event"
+	"github.com/chihaya/chihaya/server/store"
+	"github.com/chihaya/chihaya/tracker"
+)
+
+func init() {
+	tracker.RegisterAnnounceMiddleware("store_swarm_interaction", announceSwarmInteraction)
+}
+
+// FailedSwarmInteraction represents an error that indicates that the
+// interaction of a peer with a swarm failed.
+type FailedSwarmInteraction string
+
+// Error satisfies the error interface for FailedSwarmInteraction.
+func (f FailedSwarmInteraction) Error() string { return string(f) }
+
+// announceSwarmInteraction provides a middleware that manages swarm
+// interactions for a peer based on the announce.
+func announceSwarmInteraction(next tracker.AnnounceHandler) tracker.AnnounceHandler {
+	return func(cfg *chihaya.TrackerConfig, req *chihaya.AnnounceRequest, resp *chihaya.AnnounceResponse) (err error) {
+		if req.IPv4 != nil {
+			err = updatePeerStore(req, req.Peer4())
+			if err != nil {
+				return FailedSwarmInteraction(err.Error())
+			}
+		}
+
+		if req.IPv6 != nil {
+			err = updatePeerStore(req, req.Peer6())
+			if err != nil {
+				return FailedSwarmInteraction(err.Error())
+			}
+		}
+
+		return next(cfg, req, resp)
+	}
+}
+
+func updatePeerStore(req *chihaya.AnnounceRequest, peer chihaya.Peer) (err error) {
+	storage := store.MustGetStore()
+
+	switch {
+	case req.Event == event.Stopped:
+		err = storage.DeleteSeeder(req.InfoHash, peer)
+		if err != nil && err != store.ErrResourceDoesNotExist {
+			return err
+		}
+
+		err = storage.DeleteLeecher(req.InfoHash, peer)
+		if err != nil && err != store.ErrResourceDoesNotExist {
+			return err
+		}
+
+	case req.Event == event.Completed || req.Left == 0:
+		err = storage.GraduateLeecher(req.InfoHash, peer)
+		if err != nil {
+			return err
+		}
+	default:
+		err = storage.PutLeecher(req.InfoHash, peer)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
diff --git a/server/store/peer_store.go b/server/store/peer_store.go
index 1cb88b5..aada1cd 100644
--- a/server/store/peer_store.go
+++ b/server/store/peer_store.go
@@ -33,7 +33,11 @@ type PeerStore interface {
 
 	// GraduateLeecher promotes a peer from a leecher to a seeder for the
 	// infoHash within the PeerStore.
+	//
+	// If the given Peer is not a leecher, it will still be added to the
+	// list of seeders and no error will be returned.
 	GraduateLeecher(infoHash chihaya.InfoHash, p chihaya.Peer) error
+
 	// AnnouncePeers returns a list of both IPv4, and IPv6 peers for an
 	// announce.
 	//