Change torrent capacity to not return a pointer

It's an unnecessary complication for a storage implementer.

go.mod

@@ -16,7 +16,7 @@ require (
 	github.com/anacrolix/missinggo/perf v1.0.0
 	github.com/anacrolix/missinggo/v2 v2.5.2
 	github.com/anacrolix/multiless v0.1.1-0.20210529082330-de2f6cf29619
-	github.com/anacrolix/squirrel v0.1.0
+	github.com/anacrolix/squirrel v0.1.1-0.20210914065657-81bc5ecdc43a
 	github.com/anacrolix/sync v0.4.0
 	github.com/anacrolix/tagflag v1.3.0
 	github.com/anacrolix/upnp v0.1.2-0.20200416075019-5e9378ed1425

go.sum

@@ -124,6 +124,8 @@ github.com/anacrolix/multiless v0.1.1-0.20210529082330-de2f6cf29619 h1:ZkusP2EHx
 github.com/anacrolix/multiless v0.1.1-0.20210529082330-de2f6cf29619/go.mod h1:TrCLEZfIDbMVfLoQt5tOoiBS/uq4y8+ojuEVVvTNPX4=
 github.com/anacrolix/squirrel v0.1.0 h1:Zz7XUFUr2ozhsTvzwLdmrFpduoTHtBNTB/KZQ4Ivh00=
 github.com/anacrolix/squirrel v0.1.0/go.mod h1:YzgVvikMdFD441oTWlNG189bpKabO9Sbf3uCSVgca04=
+github.com/anacrolix/squirrel v0.1.1-0.20210914065657-81bc5ecdc43a h1:8LAUQgDPqnzuF/WrGQzTY6i+bVO/FpA90Hi6jXA+2vQ=
+github.com/anacrolix/squirrel v0.1.1-0.20210914065657-81bc5ecdc43a/go.mod h1:YzgVvikMdFD441oTWlNG189bpKabO9Sbf3uCSVgca04=
 github.com/anacrolix/stm v0.1.0/go.mod h1:ZKz7e7ERWvP0KgL7WXfRjBXHNRhlVRlbBQecqFtPq+A=
 github.com/anacrolix/stm v0.1.1-0.20191106051447-e749ba3531cf/go.mod h1:zoVQRvSiGjGoTmbM0vSLIiaKjWtNPeTvXUSdJQA4hsg=
 github.com/anacrolix/stm v0.2.0/go.mod h1:zoVQRvSiGjGoTmbM0vSLIiaKjWtNPeTvXUSdJQA4hsg=

request-strategy/order.go

@@ -6,6 +6,7 @@ import (
 	"sync"
 
 	"github.com/anacrolix/multiless"
+	"github.com/anacrolix/torrent/storage"
 
 	pp "github.com/anacrolix/torrent/peer_protocol"
 	"github.com/anacrolix/torrent/types"
@@ -96,8 +97,8 @@ func getRequestablePieces(input Input) (ret []requestablePiece) {
 	pieces := make([]filterPiece, 0, maxPieces)
 	ret = make([]requestablePiece, 0, maxPieces)
 	// Storage capacity left for this run, keyed by the storage capacity pointer on the storage
-	// TorrentImpl.
-	storageLeft := make(map[*func() *int64]*int64)
+	// TorrentImpl. A nil value means no capacity limit.
+	storageLeft := make(map[storage.TorrentCapacity]*int64)
 	for _t := range input.Torrents {
 		// TODO: We could do metainfo requests here.
 		t := &filterTorrent{
@@ -107,7 +108,12 @@ func getRequestablePieces(input Input) (ret []requestablePiece) {
 		key := t.Capacity
 		if key != nil {
 			if _, ok := storageLeft[key]; !ok {
-				storageLeft[key] = (*key)()
+				capacity, ok := (*key)()
+				if ok {
+					storageLeft[key] = &capacity
+				} else {
+					storageLeft[key] = nil
+				}
 			}
 			t.storageLeft = storageLeft[key]
 		}

request-strategy/torrent.go

@@ -1,8 +1,12 @@
 package request_strategy
 
+import (
+	"github.com/anacrolix/torrent/storage"
+)
+
 type Torrent struct {
 	Pieces   []Piece
-	Capacity *func() *int64
+	Capacity storage.TorrentCapacity
 	Peers    []Peer // not closed.
 	// Some value that's unique and stable between runs. Could even use the infohash?
 	StableId uintptr

storage/disabled/disabled.go

@@ -9,11 +9,9 @@ import (
 
 type Client struct{}
 
-var capacity int64
-
 func (c Client) OpenTorrent(info *metainfo.Info, infoHash metainfo.Hash) (storage.TorrentImpl, error) {
-	capFunc := func() *int64 {
-		return &capacity
+	capFunc := func() (int64, bool) {
+		return 0, true
 	}
 	return storage.TorrentImpl{
 		Piece: func(piece metainfo.Piece) storage.PieceImpl {
@@ -26,10 +24,6 @@ func (c Client) OpenTorrent(info *metainfo.Info, infoHash metainfo.Hash) (storag
 	}, nil
 }
 
-func (c Client) capacity() *int64 {
-	return &capacity
-}
-
 type Piece struct{}
 
 func (Piece) ReadAt(p []byte, off int64) (n int, err error) {

storage/interface.go

@@ -16,12 +16,16 @@ type ClientImpl interface {
 	OpenTorrent(info *metainfo.Info, infoHash metainfo.Hash) (TorrentImpl, error)
 }
 
+type TorrentCapacity *func() (cap int64, capped bool)
+
 // Data storage bound to a torrent.
 type TorrentImpl struct {
 	Piece func(p metainfo.Piece) PieceImpl
 	Close func() error
-	// Storages that share the same value, will provide a pointer to the same function.
-	Capacity *func() *int64
+	// Storages that share the same space, will provide equal pointers. The function is called once
+	// to determine the storage for torrents sharing the same function pointer, and mutated in
+	// place.
+	Capacity TorrentCapacity
 }
 
 // Interacts with torrent piece data. Optional interfaces to implement include:

storage/sqlite/direct.go

@@ -35,7 +35,7 @@ func NewWrappingClient(cache *squirrel.Cache) storage.ClientImpl {
 
 type client struct {
 	*squirrel.Cache
-	capacity func() *int64
+	capacity func() (int64, bool)
 }
 
 func (c *client) OpenTorrent(info *metainfo.Info, infoHash metainfo.Hash) (storage.TorrentImpl, error) {