Implement new puller routine (fixes #33)

main.go

@@ -41,7 +41,7 @@ type Options struct {
 
 type DebugOptions struct {
 	LogSource    bool     `long:"log-source"`
-	TraceModel   []string `long:"trace-model" value-name:"TRACE" description:"idx, net, file, need"`
+	TraceModel   []string `long:"trace-model" value-name:"TRACE" description:"idx, net, file, need, pull"`
 	TraceConnect bool     `long:"trace-connect"`
 	Profiler     string   `long:"profiler" value-name:"ADDR"`
 }
@@ -54,8 +54,7 @@ type DiscoveryOptions struct {
 }
 
 type AdvancedOptions struct {
-	RequestsInFlight int           `long:"reqs-in-flight" description:"Parallell in flight requests per file" default:"4" value-name:"REQS"`
+	RequestsInFlight int           `long:"reqs-in-flight" description:"Parallell in flight requests per node" default:"8" value-name:"REQS"`
-	FilesInFlight    int           `long:"files-in-flight" description:"Parallell in flight file pulls" default:"8" value-name:"FILES"`
 	LimitRate        int           `long:"send-rate" description:"Rate limit for outgoing data" default:"0" value-name:"KBPS"`
 	ScanInterval     time.Duration `long:"scan-intv" description:"Repository scan interval" default:"60s" value-name:"INTV"`
 	ConnInterval     time.Duration `long:"conn-intv" description:"Node reconnect interval" default:"60s" value-name:"INTV"`
@@ -205,7 +204,7 @@ func main() {
 			infoln("Deletes from peer nodes are allowed")
 		}
 		okln("Ready to synchronize (read-write)")
-		m.StartRW(!opts.NoDelete, opts.Advanced.FilesInFlight, opts.Advanced.RequestsInFlight)
+		m.StartRW(!opts.NoDelete, opts.Advanced.RequestsInFlight)
 	} else {
 		okln("Ready to synchronize (read only; no external updates accepted)")
 	}

model/blocks.go

@@ -7,15 +7,15 @@ import (
 )
 
 type Block struct {
-	Offset uint64
+	Offset int64
-	Length uint32
+	Size   uint32
 	Hash   []byte
 }
 
 // Blocks returns the blockwise hash of the reader.
 func Blocks(r io.Reader, blocksize int) ([]Block, error) {
 	var blocks []Block
-	var offset uint64
+	var offset int64
 	for {
 		lr := &io.LimitedReader{r, int64(blocksize)}
 		hf := sha256.New()
@@ -30,11 +30,11 @@ func Blocks(r io.Reader, blocksize int) ([]Block, error) {
 
 		b := Block{
 			Offset: offset,
-			Length: uint32(n),
+			Size:   uint32(n),
 			Hash:   hf.Sum(nil),
 		}
 		blocks = append(blocks, b)
-		offset += uint64(n)
+		offset += int64(n)
 	}
 
 	return blocks, nil

model/blocks_test.go

@@ -52,7 +52,7 @@ func TestBlocks(t *testing.T) {
 			t.Fatalf("Incorrect number of blocks %d != %d", l, len(test.hash))
 		} else {
 			i := 0
-			for off := uint64(0); off < uint64(len(test.data)); off += uint64(test.blocksize) {
+			for off := int64(0); off < int64(len(test.data)); off += int64(test.blocksize) {
 				if blocks[i].Offset != off {
 					t.Errorf("Incorrect offset for block %d: %d != %d", i, blocks[i].Offset, off)
 				}
@@ -61,8 +61,8 @@ func TestBlocks(t *testing.T) {
 				if rem := len(test.data) - int(off); bs > rem {
 					bs = rem
 				}
-				if int(blocks[i].Length) != bs {
+				if int(blocks[i].Size) != bs {
-					t.Errorf("Incorrect length for block %d: %d != %d", i, blocks[i].Length, bs)
+					t.Errorf("Incorrect length for block %d: %d != %d", i, blocks[i].Size, bs)
 				}
 				if h := fmt.Sprintf("%x", blocks[i].Hash); h != test.hash[i] {
 					t.Errorf("Incorrect block hash %q != %q", h, test.hash[i])
@@ -106,8 +106,8 @@ func TestDiff(t *testing.T) {
 				if d[j].Offset != test.d[j].Offset {
 					t.Errorf("Incorrect offset for diff %d block %d; %d != %d", i, j, d[j].Offset, test.d[j].Offset)
 				}
-				if d[j].Length != test.d[j].Length {
+				if d[j].Size != test.d[j].Size {
-					t.Errorf("Incorrect length for diff %d block %d; %d != %d", i, j, d[j].Length, test.d[j].Length)
+					t.Errorf("Incorrect length for diff %d block %d; %d != %d", i, j, d[j].Size, test.d[j].Size)
 				}
 			}
 		}

model/filemonitor.go

@@ -0,0 +1,154 @@
+package model
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"os"
+	"path"
+	"sync"
+	"time"
+
+	"github.com/calmh/syncthing/buffers"
+)
+
+type fileMonitor struct {
+	name        string // in-repo name
+	path        string // full path
+	writeDone   sync.WaitGroup
+	model       *Model
+	global      File
+	localBlocks []Block
+	copyError   error
+	writeError  error
+}
+
+func (m *fileMonitor) FileBegins(cc <-chan content) error {
+	tmp := tempName(m.path, m.global.Modified)
+
+	dir := path.Dir(tmp)
+	_, err := os.Stat(dir)
+	if err != nil && os.IsNotExist(err) {
+		os.MkdirAll(dir, 0777)
+	}
+
+	outFile, err := os.Create(tmp)
+	if err != nil {
+		return err
+	}
+
+	m.writeDone.Add(1)
+
+	var writeWg sync.WaitGroup
+	if len(m.localBlocks) > 0 {
+		writeWg.Add(1)
+		inFile, err := os.Open(m.path)
+		if err != nil {
+			return err
+		}
+
+		// Copy local blocks, close infile when done
+		go m.copyLocalBlocks(inFile, outFile, &writeWg)
+	}
+
+	// Write remote blocks,
+	writeWg.Add(1)
+	go m.copyRemoteBlocks(cc, outFile, &writeWg)
+
+	// Wait for both writing routines, then close the outfile
+	go func() {
+		writeWg.Wait()
+		outFile.Close()
+		m.writeDone.Done()
+	}()
+
+	return nil
+}
+
+func (m *fileMonitor) copyLocalBlocks(inFile, outFile *os.File, writeWg *sync.WaitGroup) {
+	defer inFile.Close()
+	defer writeWg.Done()
+
+	var buf = buffers.Get(BlockSize)
+	defer buffers.Put(buf)
+
+	for _, lb := range m.localBlocks {
+		buf = buf[:lb.Size]
+		_, err := inFile.ReadAt(buf, lb.Offset)
+		if err != nil {
+			m.copyError = err
+			return
+		}
+		_, err = outFile.WriteAt(buf, lb.Offset)
+		if err != nil {
+			m.copyError = err
+			return
+		}
+	}
+}
+
+func (m *fileMonitor) copyRemoteBlocks(cc <-chan content, outFile *os.File, writeWg *sync.WaitGroup) {
+	defer writeWg.Done()
+
+	for content := range cc {
+		_, err := outFile.WriteAt(content.data, content.offset)
+		buffers.Put(content.data)
+		if err != nil {
+			m.writeError = err
+			return
+		}
+	}
+}
+
+func (m *fileMonitor) FileDone() error {
+	m.writeDone.Wait()
+
+	tmp := tempName(m.path, m.global.Modified)
+	defer os.Remove(tmp)
+
+	err := hashCheck(tmp, m.global.Blocks)
+	if err != nil {
+		return fmt.Errorf("%s: %s (tmp) (deleting)", path.Base(m.name), err.Error())
+	}
+
+	err = os.Chtimes(tmp, time.Unix(m.global.Modified, 0), time.Unix(m.global.Modified, 0))
+	if err != nil {
+		return err
+	}
+
+	err = os.Chmod(tmp, os.FileMode(m.global.Flags&0777))
+	if err != nil {
+		return err
+	}
+
+	err = os.Rename(tmp, m.path)
+	if err != nil {
+		return err
+	}
+
+	go m.model.updateLocalLocked(m.global)
+	return nil
+}
+
+func hashCheck(name string, correct []Block) error {
+	rf, err := os.Open(name)
+	if err != nil {
+		return err
+	}
+	defer rf.Close()
+
+	current, err := Blocks(rf, BlockSize)
+	if err != nil {
+		return err
+	}
+	if len(current) != len(correct) {
+		return errors.New("incorrect number of blocks")
+	}
+	for i := range current {
+		if bytes.Compare(current[i].Hash, correct[i].Hash) != 0 {
+			return fmt.Errorf("hash mismatch: %x != %x", current[i], correct[i])
+		}
+	}
+
+	return nil
+}

model/filequeue.go

@@ -0,0 +1,199 @@
+package model
+
+import (
+	"log"
+	"sort"
+	"sync"
+	"time"
+)
+
+type Resolver interface {
+	WhoHas(string) []string
+}
+
+type Monitor interface {
+	FileBegins(<-chan content) error
+	FileDone() error
+}
+
+type FileQueue struct {
+	resolver Resolver
+	files    queuedFileList
+	lock     sync.Mutex
+	sorted   bool
+}
+
+type queuedFile struct {
+	name         string
+	blocks       []Block
+	activeBlocks []bool
+	given        int
+	remaining    int
+	channel      chan content
+	nodes        []string
+	nodesChecked time.Time
+	monitor      Monitor
+}
+
+type content struct {
+	offset int64
+	data   []byte
+}
+
+type queuedFileList []queuedFile
+
+func (l queuedFileList) Len() int { return len(l) }
+
+func (l queuedFileList) Swap(a, b int) { l[a], l[b] = l[b], l[a] }
+
+func (l queuedFileList) Less(a, b int) bool {
+	// Sort by most blocks already given out, then alphabetically
+	if l[a].given != l[b].given {
+		return l[a].given > l[b].given
+	}
+	return l[a].name < l[b].name
+}
+
+type queuedBlock struct {
+	name  string
+	block Block
+	index int
+}
+
+func (q *FileQueue) Add(name string, blocks []Block, monitor Monitor) {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
+	q.files = append(q.files, queuedFile{
+		name:         name,
+		blocks:       blocks,
+		activeBlocks: make([]bool, len(blocks)),
+		remaining:    len(blocks),
+		channel:      make(chan content),
+		monitor:      monitor,
+	})
+	q.sorted = false
+}
+
+func (q *FileQueue) Len() int {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
+	return len(q.files)
+}
+
+func (q *FileQueue) Get(nodeID string) (queuedBlock, bool) {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
+	if !q.sorted {
+		sort.Sort(q.files)
+		q.sorted = true
+	}
+
+	for i := range q.files {
+		if time.Since(q.files[i].nodesChecked) > 5*time.Second {
+			// Refresh node list every now and then
+			q.files[i].nodes = q.resolver.WhoHas(q.files[i].name)
+		}
+
+		if len(q.files[i].nodes) == 0 {
+			// Noone has the file we want; abort.
+			if q.files[i].remaining != len(q.files[i].blocks) {
+				// We have already started on this file; close it down
+				close(q.files[i].channel)
+				if mon := q.files[i].monitor; mon != nil {
+					mon.FileDone()
+				}
+			}
+			q.deleteIndex(i)
+			return queuedBlock{}, false
+		}
+
+		qf := q.files[i]
+		for _, ni := range qf.nodes {
+			// Find and return the next block in the queue
+			if ni == nodeID {
+				for j, b := range qf.blocks {
+					if !qf.activeBlocks[j] {
+						q.files[i].activeBlocks[j] = true
+						q.files[i].given++
+						return queuedBlock{
+							name:  qf.name,
+							block: b,
+							index: j,
+						}, true
+					}
+				}
+				break
+			}
+		}
+	}
+
+	// We found nothing to do
+	return queuedBlock{}, false
+}
+
+func (q *FileQueue) Done(file string, offset int64, data []byte) {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
+	c := content{
+		offset: offset,
+		data:   data,
+	}
+	for i, qf := range q.files {
+		if qf.name == file {
+			if qf.monitor != nil && qf.remaining == len(qf.blocks) {
+				err := qf.monitor.FileBegins(qf.channel)
+				if err != nil {
+					log.Printf("WARNING: %s: %v (not synced)", qf.name, err)
+					q.deleteIndex(i)
+					return
+				}
+			}
+
+			qf.channel <- c
+			q.files[i].remaining--
+
+			if q.files[i].remaining == 0 {
+				close(qf.channel)
+				q.deleteIndex(i)
+				if qf.monitor != nil {
+					err := qf.monitor.FileDone()
+					if err != nil {
+						log.Printf("WARNING: %s: %v", qf.name, err)
+					}
+				}
+			}
+			return
+		}
+	}
+	panic("unreachable")
+}
+
+func (q *FileQueue) Queued(file string) bool {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
+	for _, qf := range q.files {
+		if qf.name == file {
+			return true
+		}
+	}
+	return false
+}
+
+func (q *FileQueue) QueuedFiles() (files []string) {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
+	for _, qf := range q.files {
+		files = append(files, qf.name)
+	}
+	return
+}
+
+func (q *FileQueue) deleteIndex(i int) {
+	q.files = q.files[:i+copy(q.files[i:], q.files[i+1:])]
+}

model/filequeue_test.go

@@ -0,0 +1,276 @@
+package model
+
+import (
+	"reflect"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"testing"
+)
+
+type fakeResolver struct{}
+
+func (fakeResolver) WhoHas(n string) []string {
+	if strings.HasPrefix(n, "a-") {
+		return []string{"a", "nodeID"}
+	} else if strings.HasPrefix(n, "b-") {
+		return []string{"b", "nodeID"}
+	}
+	return []string{"a", "b", "nodeID"}
+}
+
+func TestFileQueueAdd(t *testing.T) {
+	q := FileQueue{}
+	q.Add("foo", nil, nil)
+}
+
+func TestFileQueueAddSorting(t *testing.T) {
+	q := FileQueue{resolver: fakeResolver{}}
+	q.Add("zzz", []Block{{Offset: 0, Size: 128}, {Offset: 128, Size: 128}}, nil)
+	q.Add("aaa", []Block{{Offset: 0, Size: 128}, {Offset: 128, Size: 128}}, nil)
+	b, _ := q.Get("nodeID")
+	if b.name != "aaa" {
+		t.Errorf("Incorrectly sorted get: %+v", b)
+	}
+
+	q = FileQueue{resolver: fakeResolver{}}
+	q.Add("zzz", []Block{{Offset: 0, Size: 128}, {Offset: 128, Size: 128}}, nil)
+	b, _ = q.Get("nodeID") // Start on zzzz
+	if b.name != "zzz" {
+		t.Errorf("Incorrectly sorted get: %+v", b)
+	}
+	q.Add("aaa", []Block{{Offset: 0, Size: 128}, {Offset: 128, Size: 128}}, nil)
+	b, _ = q.Get("nodeID")
+	if b.name != "zzz" {
+		// Continue rather than starting a new file
+		t.Errorf("Incorrectly sorted get: %+v", b)
+	}
+}
+
+func TestFileQueueLen(t *testing.T) {
+	q := FileQueue{}
+	q.Add("foo", nil, nil)
+	q.Add("bar", nil, nil)
+
+	if l := q.Len(); l != 2 {
+		t.Errorf("Incorrect len %d != 2 after adds", l)
+	}
+}
+
+func TestFileQueueGet(t *testing.T) {
+	q := FileQueue{resolver: fakeResolver{}}
+	q.Add("foo", []Block{
+		{Offset: 0, Size: 128, Hash: []byte("some foo hash bytes")},
+		{Offset: 128, Size: 128, Hash: []byte("some other foo hash bytes")},
+		{Offset: 256, Size: 128, Hash: []byte("more foo hash bytes")},
+	}, nil)
+	q.Add("bar", []Block{
+		{Offset: 0, Size: 128, Hash: []byte("some bar hash bytes")},
+		{Offset: 128, Size: 128, Hash: []byte("some other bar hash bytes")},
+	}, nil)
+
+	// First get should return the first block of the first file
+
+	expected := queuedBlock{
+		name: "bar",
+		block: Block{
+			Offset: 0,
+			Size:   128,
+			Hash:   []byte("some bar hash bytes"),
+		},
+	}
+	actual, ok := q.Get("nodeID")
+
+	if !ok {
+		t.Error("Unexpected non-OK Get()")
+	}
+	if !reflect.DeepEqual(expected, actual) {
+		t.Errorf("Incorrect block returned (first)\n  E: %+v\n  A: %+v", expected, actual)
+	}
+
+	// Second get should return the next block of the first file
+
+	expected = queuedBlock{
+		name: "bar",
+		block: Block{
+			Offset: 128,
+			Size:   128,
+			Hash:   []byte("some other bar hash bytes"),
+		},
+		index: 1,
+	}
+	actual, ok = q.Get("nodeID")
+
+	if !ok {
+		t.Error("Unexpected non-OK Get()")
+	}
+	if !reflect.DeepEqual(expected, actual) {
+		t.Errorf("Incorrect block returned (second)\n  E: %+v\n  A: %+v", expected, actual)
+	}
+
+	// Third get should return the first block of the second file
+
+	expected = queuedBlock{
+		name: "foo",
+		block: Block{
+			Offset: 0,
+			Size:   128,
+			Hash:   []byte("some foo hash bytes"),
+		},
+	}
+	actual, ok = q.Get("nodeID")
+
+	if !ok {
+		t.Error("Unexpected non-OK Get()")
+	}
+	if !reflect.DeepEqual(expected, actual) {
+		t.Errorf("Incorrect block returned (third)\n  E: %+v\n  A: %+v", expected, actual)
+	}
+}
+
+/*
+func TestFileQueueDone(t *testing.T) {
+	ch := make(chan content)
+	var recv sync.WaitGroup
+	recv.Add(1)
+	go func() {
+		content := <-ch
+		if bytes.Compare(content.data, []byte("first block bytes")) != 0 {
+			t.Error("Incorrect data in first content block")
+		}
+
+		content = <-ch
+		if bytes.Compare(content.data, []byte("second block bytes")) != 0 {
+			t.Error("Incorrect data in second content block")
+		}
+
+		_, ok := <-ch
+		if ok {
+			t.Error("Content channel not closed")
+		}
+
+		recv.Done()
+	}()
+
+	q := FileQueue{resolver: fakeResolver{}}
+	q.Add("foo", []Block{
+		{Offset: 0, Length: 128, Hash: []byte("some foo hash bytes")},
+		{Offset: 128, Length: 128, Hash: []byte("some other foo hash bytes")},
+	}, ch)
+
+	b0, _ := q.Get("nodeID")
+	b1, _ := q.Get("nodeID")
+
+	q.Done(b0.name, b0.block.Offset, []byte("first block bytes"))
+	q.Done(b1.name, b1.block.Offset, []byte("second block bytes"))
+
+	recv.Wait()
+
+	// Queue should now have one file less
+
+	if l := q.Len(); l != 0 {
+		t.Error("Queue not empty")
+	}
+
+	_, ok := q.Get("nodeID")
+	if ok {
+		t.Error("Unexpected OK Get()")
+	}
+}
+*/
+
+func TestFileQueueGetNodeIDs(t *testing.T) {
+	q := FileQueue{resolver: fakeResolver{}}
+	q.Add("a-foo", []Block{
+		{Offset: 0, Size: 128, Hash: []byte("some foo hash bytes")},
+		{Offset: 128, Size: 128, Hash: []byte("some other foo hash bytes")},
+		{Offset: 256, Size: 128, Hash: []byte("more foo hash bytes")},
+	}, nil)
+	q.Add("b-bar", []Block{
+		{Offset: 0, Size: 128, Hash: []byte("some bar hash bytes")},
+		{Offset: 128, Size: 128, Hash: []byte("some other bar hash bytes")},
+	}, nil)
+
+	expected := queuedBlock{
+		name: "b-bar",
+		block: Block{
+			Offset: 0,
+			Size:   128,
+			Hash:   []byte("some bar hash bytes"),
+		},
+	}
+	actual, ok := q.Get("b")
+	if !ok {
+		t.Error("Unexpected non-OK Get()")
+	}
+	if !reflect.DeepEqual(expected, actual) {
+		t.Errorf("Incorrect block returned\n  E: %+v\n  A: %+v", expected, actual)
+	}
+
+	expected = queuedBlock{
+		name: "a-foo",
+		block: Block{
+			Offset: 0,
+			Size:   128,
+			Hash:   []byte("some foo hash bytes"),
+		},
+	}
+	actual, ok = q.Get("a")
+	if !ok {
+		t.Error("Unexpected non-OK Get()")
+	}
+	if !reflect.DeepEqual(expected, actual) {
+		t.Errorf("Incorrect block returned\n  E: %+v\n  A: %+v", expected, actual)
+	}
+
+	expected = queuedBlock{
+		name: "a-foo",
+		block: Block{
+			Offset: 128,
+			Size:   128,
+			Hash:   []byte("some other foo hash bytes"),
+		},
+		index: 1,
+	}
+	actual, ok = q.Get("nodeID")
+	if !ok {
+		t.Error("Unexpected non-OK Get()")
+	}
+	if !reflect.DeepEqual(expected, actual) {
+		t.Errorf("Incorrect block returned\n  E: %+v\n  A: %+v", expected, actual)
+	}
+}
+
+func TestFileQueueThreadHandling(t *testing.T) {
+	// This should pass with go test -race
+
+	const n = 100
+	var total int
+	var blocks []Block
+	for i := 1; i <= n; i++ {
+		blocks = append(blocks, Block{Offset: int64(i), Size: 1})
+		total += i
+	}
+
+	q := FileQueue{resolver: fakeResolver{}}
+	q.Add("foo", blocks, nil)
+
+	var start = make(chan bool)
+	var gotTot uint32
+	var wg sync.WaitGroup
+	wg.Add(n)
+	for i := 1; i <= n; i++ {
+		go func() {
+			<-start
+			b, _ := q.Get("nodeID")
+			atomic.AddUint32(&gotTot, uint32(b.block.Offset))
+			wg.Done()
+		}()
+	}
+
+	close(start)
+	wg.Wait()
+	if int(gotTot) != total {
+		t.Error("Total mismatch; %d != %d", gotTot, total)
+	}
+}

model/model.go

@@ -34,9 +34,10 @@ type Model struct {
 	global    map[string]File // the latest version of each file as it exists in the cluster
 	local     map[string]File // the files we currently have locally on disk
 	remote    map[string]map[string]File
-	need      map[string]bool // the files we need to update
 	protoConn map[string]Connection
 	rawConn   map[string]io.Closer
+	fq        FileQueue // queue for files to fetch
+	dq        chan File // queue for files to delete
 
 	updatedLocal int64 // timestamp of last update to local
 	updateGlobal int64 // timestamp of last update to remote
@@ -45,8 +46,6 @@ type Model struct {
 	lastIdxBcastRequest time.Time
 
 	rwRunning bool
-	parallellFiles int
-	paralllelReqs  int
 	delete    bool
 
 	trace map[string]bool
@@ -54,13 +53,14 @@ type Model struct {
 	fileLastChanged   map[string]time.Time
 	fileWasSuppressed map[string]int
 
+	parallellRequests int
 	limitRequestRate  chan struct{}
 }
 
 type Connection interface {
 	ID() string
 	Index([]protocol.FileInfo)
-	Request(name string, offset uint64, size uint32, hash []byte) ([]byte, error)
+	Request(name string, offset int64, size uint32, hash []byte) ([]byte, error)
 	Statistics() protocol.Statistics
 }
 
@@ -86,14 +86,15 @@ func NewModel(dir string) *Model {
 		global:            make(map[string]File),
 		local:             make(map[string]File),
 		remote:            make(map[string]map[string]File),
-		need:              make(map[string]bool),
 		protoConn:         make(map[string]Connection),
 		rawConn:           make(map[string]io.Closer),
 		lastIdxBcast:      time.Now(),
 		trace:             make(map[string]bool),
 		fileLastChanged:   make(map[string]time.Time),
 		fileWasSuppressed: make(map[string]int),
+		dq:                make(chan File),
 	}
+	m.fq.resolver = m
 
 	go m.broadcastIndexLoop()
 	return m
@@ -124,7 +125,7 @@ func (m *Model) Trace(t string) {
 // StartRW starts read/write processing on the current model. When in
 // read/write mode the model will attempt to keep in sync with the cluster by
 // pulling needed files from peer nodes.
-func (m *Model) StartRW(del bool, pfiles, preqs int) {
+func (m *Model) StartRW(del bool, threads int) {
 	m.Lock()
 	defer m.Unlock()
 
@@ -134,11 +135,12 @@ func (m *Model) StartRW(del bool, pfiles, preqs int) {
 
 	m.rwRunning = true
 	m.delete = del
-	m.parallellFiles = pfiles
+	m.parallellRequests = threads
-	m.paralllelReqs = preqs
 
 	go m.cleanTempFiles()
-	go m.puller()
+	if del {
+		go m.deleteFiles()
+	}
 }
 
 // Generation returns an opaque integer that is guaranteed to increment on
@@ -231,7 +233,7 @@ func (m *Model) NeedFiles() (files []File, bytes int) {
 	m.RLock()
 	defer m.RUnlock()
 
-	for n := range m.need {
+	for _, n := range m.fq.QueuedFiles() {
 		f := m.global[n]
 		files = append(files, f)
 		bytes += f.Size()
@@ -321,7 +323,7 @@ func (m *Model) Close(node string, err error) {
 
 // Request returns the specified data segment by reading it from local disk.
 // Implements the protocol.Model interface.
-func (m *Model) Request(nodeID, name string, offset uint64, size uint32, hash []byte) ([]byte, error) {
+func (m *Model) Request(nodeID, name string, offset int64, size uint32, hash []byte) ([]byte, error) {
 	// Verify that the requested file exists in the local and global model.
 	m.RLock()
 	lf, localOk := m.local[name]
@@ -346,7 +348,7 @@ func (m *Model) Request(nodeID, name string, offset uint64, size uint32, hash []
 	defer fd.Close()
 
 	buf := buffers.Get(int(size))
-	_, err = fd.ReadAt(buf, int64(offset))
+	_, err = fd.ReadAt(buf, offset)
 	if err != nil {
 		return nil, err
 	}
@@ -446,6 +448,39 @@ func (m *Model) AddConnection(rawConn io.Closer, protoConn Connection) {
 	go func() {
 		protoConn.Index(idx)
 	}()
+
+	if m.rwRunning {
+		for i := 0; i < m.parallellRequests; i++ {
+			i := i
+			go func() {
+				if m.trace["pull"] {
+					log.Println("PULL: Starting", nodeID, i)
+				}
+				for {
+					m.RLock()
+					if _, ok := m.protoConn[nodeID]; !ok {
+						if m.trace["pull"] {
+							log.Println("PULL: Exiting", nodeID, i)
+						}
+						m.RUnlock()
+						return
+					}
+					m.RUnlock()
+
+					qb, ok := m.fq.Get(nodeID)
+					if ok {
+						if m.trace["pull"] {
+							log.Println("PULL: Request", nodeID, i, qb.name, qb.block.Offset)
+						}
+						data, _ := protoConn.Request(qb.name, qb.block.Offset, qb.block.Size, qb.block.Hash)
+						m.fq.Done(qb.name, qb.block.Offset, data)
+					} else {
+						time.Sleep(1 * time.Second)
+					}
+				}
+			}()
+		}
+	}
 }
 
 func (m *Model) shouldSuppressChange(name string) bool {
@@ -488,7 +523,7 @@ func (m *Model) protocolIndex() []protocol.FileInfo {
 	return index
 }
 
-func (m *Model) requestGlobal(nodeID, name string, offset uint64, size uint32, hash []byte) ([]byte, error) {
+func (m *Model) requestGlobal(nodeID, name string, offset int64, size uint32, hash []byte) ([]byte, error) {
 	m.RLock()
 	nc, ok := m.protoConn[nodeID]
 	m.RUnlock()
@@ -520,7 +555,7 @@ func (m *Model) broadcastIndexLoop() {
 			for _, node := range m.protoConn {
 				node := node
 				if m.trace["net"] {
-					log.Printf("NET IDX(out/loop): %s: %d files", node.ID, len(idx))
+					log.Printf("NET IDX(out/loop): %s: %d files", node.ID(), len(idx))
 				}
 				go func() {
 					node.Index(idx)
@@ -558,6 +593,12 @@ func (m *Model) markDeletedLocals(newLocal map[string]File) bool {
 	return updated
 }
 
+func (m *Model) updateLocalLocked(f File) {
+	m.Lock()
+	m.updateLocal(f)
+	m.Unlock()
+}
+
 func (m *Model) updateLocal(f File) {
 	if ef, ok := m.local[f.Name]; !ok || !ef.Equals(f) {
 		m.local[f.Name] = f
@@ -610,8 +651,10 @@ func (m *Model) recomputeGlobal() {
 
 // Must be called with the write lock held.
 func (m *Model) recomputeNeed() {
-	m.need = make(map[string]bool)
 	for n, gf := range m.global {
+		if m.fq.Queued(n) {
+			continue
+		}
 		lf, ok := m.local[n]
 		if !ok || gf.NewerThan(lf) {
 			if gf.Flags&protocol.FlagInvalid != 0 {
@@ -627,15 +670,28 @@ func (m *Model) recomputeNeed() {
 				continue
 			}
 			if m.trace["need"] {
-				log.Println("NEED:", ok, lf, gf)
+				log.Printf("NEED: lf:%v gf:%v", lf, gf)
+			}
+
+			if gf.Flags&protocol.FlagDeleted != 0 {
+				m.dq <- gf
+			} else {
+				local, remote := BlockDiff(lf.Blocks, gf.Blocks)
+				fm := fileMonitor{
+					name:        n,
+					path:        path.Clean(path.Join(m.dir, n)),
+					global:      gf,
+					model:       m,
+					localBlocks: local,
+				}
+				m.fq.Add(n, remote, &fm)
 			}
-			m.need[n] = true
 		}
 	}
 }
 
 // Must be called with the read lock held.
-func (m *Model) whoHas(name string) []string {
+func (m *Model) WhoHas(name string) []string {
 	var remote []string
 
 	gf := m.global[name]
@@ -648,21 +704,35 @@ func (m *Model) whoHas(name string) []string {
 	return remote
 }
 
+func (m *Model) deleteFiles() {
+	for file := range m.dq {
+		if m.trace["file"] {
+			log.Println("FILE: Delete", file.Name)
+		}
+		path := path.Clean(path.Join(m.dir, file.Name))
+		err := os.Remove(path)
+		if err != nil {
+			log.Printf("WARNING: %s: %v", file.Name, err)
+		}
+		m.updateLocalLocked(file)
+	}
+}
+
 func fileFromFileInfo(f protocol.FileInfo) File {
 	var blocks = make([]Block, len(f.Blocks))
-	var offset uint64
+	var offset int64
 	for i, b := range f.Blocks {
 		blocks[i] = Block{
 			Offset: offset,
-			Length: b.Length,
+			Size:   b.Size,
 			Hash:   b.Hash,
 		}
-		offset += uint64(b.Length)
+		offset += int64(b.Size)
 	}
 	return File{
 		Name:     f.Name,
 		Flags:    f.Flags,
-		Modified: int64(f.Modified),
+		Modified: f.Modified,
 		Version:  f.Version,
 		Blocks:   blocks,
 	}
@@ -672,14 +742,14 @@ func fileInfoFromFile(f File) protocol.FileInfo {
 	var blocks = make([]protocol.BlockInfo, len(f.Blocks))
 	for i, b := range f.Blocks {
 		blocks[i] = protocol.BlockInfo{
-			Length: b.Length,
+			Size: b.Size,
 			Hash: b.Hash,
 		}
 	}
 	return protocol.FileInfo{
 		Name:     f.Name,
 		Flags:    f.Flags,
-		Modified: int64(f.Modified),
+		Modified: f.Modified,
 		Version:  f.Version,
 		Blocks:   blocks,
 	}

model/model_puller.go

@@ -1,258 +0,0 @@
-package model
-
-/*
-
-Locking
-=======
-
-These methods are never called from the outside so don't follow the locking
-policy in model.go.
-
-TODO(jb): Refactor this into smaller and cleaner pieces.
-TODO(jb): Increase performance by taking apparent peer bandwidth into account.
-
-*/
-
-import (
-	"bytes"
-	"errors"
-	"fmt"
-	"io"
-	"log"
-	"os"
-	"path"
-	"sync"
-	"time"
-
-	"github.com/calmh/syncthing/buffers"
-	"github.com/calmh/syncthing/protocol"
-)
-
-func (m *Model) pullFile(name string) error {
-	m.RLock()
-	var localFile = m.local[name]
-	var globalFile = m.global[name]
-	var nodeIDs = m.whoHas(name)
-	m.RUnlock()
-
-	if len(nodeIDs) == 0 {
-		return fmt.Errorf("%s: no connected nodes with file available", name)
-	}
-
-	filename := path.Join(m.dir, name)
-	sdir := path.Dir(filename)
-
-	_, err := os.Stat(sdir)
-	if err != nil && os.IsNotExist(err) {
-		os.MkdirAll(sdir, 0777)
-	}
-
-	tmpFilename := tempName(filename, globalFile.Modified)
-	tmpFile, err := os.Create(tmpFilename)
-	if err != nil {
-		return err
-	}
-
-	contentChan := make(chan content, 32)
-	var applyDone sync.WaitGroup
-	applyDone.Add(1)
-	go func() {
-		applyContent(contentChan, tmpFile)
-		tmpFile.Close()
-		applyDone.Done()
-	}()
-
-	local, remote := BlockDiff(localFile.Blocks, globalFile.Blocks)
-	var fetchDone sync.WaitGroup
-
-	// One local copy routine
-
-	fetchDone.Add(1)
-	go func() {
-		for _, block := range local {
-			data, err := m.Request("<local>", name, block.Offset, block.Length, block.Hash)
-			if err != nil {
-				break
-			}
-			contentChan <- content{
-				offset: int64(block.Offset),
-				data:   data,
-			}
-		}
-		fetchDone.Done()
-	}()
-
-	// N remote copy routines
-
-	var remoteBlocks = blockIterator{blocks: remote}
-	for i := 0; i < m.paralllelReqs; i++ {
-		curNode := nodeIDs[i%len(nodeIDs)]
-		fetchDone.Add(1)
-
-		go func(nodeID string) {
-			for {
-				block, ok := remoteBlocks.Next()
-				if !ok {
-					break
-				}
-				data, err := m.requestGlobal(nodeID, name, block.Offset, block.Length, block.Hash)
-				if err != nil {
-					break
-				}
-				contentChan <- content{
-					offset: int64(block.Offset),
-					data:   data,
-				}
-			}
-			fetchDone.Done()
-		}(curNode)
-	}
-
-	fetchDone.Wait()
-	close(contentChan)
-	applyDone.Wait()
-
-	err = hashCheck(tmpFilename, globalFile.Blocks)
-	if err != nil {
-		return fmt.Errorf("%s: %s (deleting)", path.Base(name), err.Error())
-	}
-
-	err = os.Chtimes(tmpFilename, time.Unix(globalFile.Modified, 0), time.Unix(globalFile.Modified, 0))
-	if err != nil {
-		return err
-	}
-
-	err = os.Chmod(tmpFilename, os.FileMode(globalFile.Flags&0777))
-	if err != nil {
-		return err
-	}
-
-	err = os.Rename(tmpFilename, filename)
-	if err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (m *Model) puller() {
-	for {
-		time.Sleep(time.Second)
-
-		var ns []string
-		m.RLock()
-		for n := range m.need {
-			ns = append(ns, n)
-		}
-		m.RUnlock()
-
-		if len(ns) == 0 {
-			continue
-		}
-
-		var limiter = make(chan bool, m.parallellFiles)
-		var allDone sync.WaitGroup
-
-		for _, n := range ns {
-			limiter <- true
-			allDone.Add(1)
-
-			go func(n string) {
-				defer func() {
-					allDone.Done()
-					<-limiter
-				}()
-
-				m.RLock()
-				f, ok := m.global[n]
-				m.RUnlock()
-
-				if !ok {
-					return
-				}
-
-				var err error
-				if f.Flags&protocol.FlagDeleted == 0 {
-					if m.trace["file"] {
-						log.Printf("FILE: Pull %q", n)
-					}
-					err = m.pullFile(n)
-				} else {
-					if m.trace["file"] {
-						log.Printf("FILE: Remove %q", n)
-					}
-					// Cheerfully ignore errors here
-					_ = os.Remove(path.Join(m.dir, n))
-				}
-				if err == nil {
-					m.Lock()
-					m.updateLocal(f)
-					m.Unlock()
-				}
-			}(n)
-		}
-
-		allDone.Wait()
-	}
-}
-
-type content struct {
-	offset int64
-	data   []byte
-}
-
-func applyContent(cc <-chan content, dst io.WriterAt) error {
-	var err error
-
-	for c := range cc {
-		_, err = dst.WriteAt(c.data, c.offset)
-		buffers.Put(c.data)
-		if err != nil {
-			return err
-		}
-	}
-
-	return nil
-}
-
-func hashCheck(name string, correct []Block) error {
-	rf, err := os.Open(name)
-	if err != nil {
-		return err
-	}
-	defer rf.Close()
-
-	current, err := Blocks(rf, BlockSize)
-	if err != nil {
-		return err
-	}
-	if len(current) != len(correct) {
-		return errors.New("incorrect number of blocks")
-	}
-	for i := range current {
-		if bytes.Compare(current[i].Hash, correct[i].Hash) != 0 {
-			return fmt.Errorf("hash mismatch: %x != %x", current[i], correct[i])
-		}
-	}
-
-	return nil
-}
-
-type blockIterator struct {
-	sync.Mutex
-	blocks []Block
-}
-
-func (i *blockIterator) Next() (b Block, ok bool) {
-	i.Lock()
-	defer i.Unlock()
-
-	if len(i.blocks) == 0 {
-		return
-	}
-
-	b, i.blocks = i.blocks[0], i.blocks[1:]
-	ok = true
-
-	return
-}

model/model_test.go

@@ -18,7 +18,7 @@ func TestNewModel(t *testing.T) {
 		t.Fatalf("NewModel returned nil")
 	}
 
-	if len(m.need) > 0 {
+	if fs, _ := m.NeedFiles(); len(fs) > 0 {
 		t.Errorf("New model should have no Need")
 	}
 
@@ -32,13 +32,13 @@ var testDataExpected = map[string]File{
 		Name:     "foo",
 		Flags:    0,
 		Modified: 0,
-		Blocks:   []Block{{Offset: 0x0, Length: 0x7, Hash: []uint8{0xae, 0xc0, 0x70, 0x64, 0x5f, 0xe5, 0x3e, 0xe3, 0xb3, 0x76, 0x30, 0x59, 0x37, 0x61, 0x34, 0xf0, 0x58, 0xcc, 0x33, 0x72, 0x47, 0xc9, 0x78, 0xad, 0xd1, 0x78, 0xb6, 0xcc, 0xdf, 0xb0, 0x1, 0x9f}}},
+		Blocks:   []Block{{Offset: 0x0, Size: 0x7, Hash: []uint8{0xae, 0xc0, 0x70, 0x64, 0x5f, 0xe5, 0x3e, 0xe3, 0xb3, 0x76, 0x30, 0x59, 0x37, 0x61, 0x34, 0xf0, 0x58, 0xcc, 0x33, 0x72, 0x47, 0xc9, 0x78, 0xad, 0xd1, 0x78, 0xb6, 0xcc, 0xdf, 0xb0, 0x1, 0x9f}}},
 	},
 	"bar": File{
 		Name:     "bar",
 		Flags:    0,
 		Modified: 0,
-		Blocks:   []Block{{Offset: 0x0, Length: 0xa, Hash: []uint8{0x2f, 0x72, 0xcc, 0x11, 0xa6, 0xfc, 0xd0, 0x27, 0x1e, 0xce, 0xf8, 0xc6, 0x10, 0x56, 0xee, 0x1e, 0xb1, 0x24, 0x3b, 0xe3, 0x80, 0x5b, 0xf9, 0xa9, 0xdf, 0x98, 0xf9, 0x2f, 0x76, 0x36, 0xb0, 0x5c}}},
+		Blocks:   []Block{{Offset: 0x0, Size: 0xa, Hash: []uint8{0x2f, 0x72, 0xcc, 0x11, 0xa6, 0xfc, 0xd0, 0x27, 0x1e, 0xce, 0xf8, 0xc6, 0x10, 0x56, 0xee, 0x1e, 0xb1, 0x24, 0x3b, 0xe3, 0x80, 0x5b, 0xf9, 0xa9, 0xdf, 0x98, 0xf9, 0x2f, 0x76, 0x36, 0xb0, 0x5c}}},
 	},
 }
 
@@ -57,7 +57,7 @@ func TestUpdateLocal(t *testing.T) {
 	fs, _ := m.Walk(false)
 	m.ReplaceLocal(fs)
 
-	if len(m.need) > 0 {
+	if fs, _ := m.NeedFiles(); len(fs) > 0 {
 		t.Fatalf("Model with only local data should have no need")
 	}
 
@@ -106,8 +106,8 @@ func TestRemoteUpdateExisting(t *testing.T) {
 	}
 	m.Index("42", []protocol.FileInfo{newFile})
 
-	if l := len(m.need); l != 1 {
+	if fs, _ := m.NeedFiles(); len(fs) != 1 {
-		t.Errorf("Model missing Need for one file (%d != 1)", l)
+		t.Errorf("Model missing Need for one file (%d != 1)", len(fs))
 	}
 }
 
@@ -123,8 +123,8 @@ func TestRemoteAddNew(t *testing.T) {
 	}
 	m.Index("42", []protocol.FileInfo{newFile})
 
-	if l1, l2 := len(m.need), 1; l1 != l2 {
+	if fs, _ := m.NeedFiles(); len(fs) != 1 {
-		t.Errorf("Model len(m.need) incorrect (%d != %d)", l1, l2)
+		t.Errorf("Model len(m.need) incorrect (%d != 1)", len(fs))
 	}
 }
 
@@ -141,8 +141,8 @@ func TestRemoteUpdateOld(t *testing.T) {
 	}
 	m.Index("42", []protocol.FileInfo{newFile})
 
-	if l1, l2 := len(m.need), 0; l1 != l2 {
+	if fs, _ := m.NeedFiles(); len(fs) != 0 {
-		t.Errorf("Model len(need) incorrect (%d != %d)", l1, l2)
+		t.Errorf("Model len(need) incorrect (%d != 0)", len(fs))
 	}
 }
 
@@ -165,16 +165,16 @@ func TestRemoteIndexUpdate(t *testing.T) {
 
 	m.Index("42", []protocol.FileInfo{foo})
 
-	if _, ok := m.need["foo"]; !ok {
+	if fs, _ := m.NeedFiles(); fs[0].Name != "foo" {
 		t.Error("Model doesn't need 'foo'")
 	}
 
 	m.IndexUpdate("42", []protocol.FileInfo{bar})
 
-	if _, ok := m.need["foo"]; !ok {
+	if fs, _ := m.NeedFiles(); fs[0].Name != "foo" {
 		t.Error("Model doesn't need 'foo'")
 	}
-	if _, ok := m.need["bar"]; !ok {
+	if fs, _ := m.NeedFiles(); fs[1].Name != "bar" {
 		t.Error("Model doesn't need 'bar'")
 	}
 }
@@ -292,8 +292,8 @@ func TestForgetNode(t *testing.T) {
 	if l1, l2 := len(m.global), len(fs); l1 != l2 {
 		t.Errorf("Model len(global) incorrect (%d != %d)", l1, l2)
 	}
-	if l1, l2 := len(m.need), 0; l1 != l2 {
+	if fs, _ := m.NeedFiles(); len(fs) != 0 {
-		t.Errorf("Model len(need) incorrect (%d != %d)", l1, l2)
+		t.Errorf("Model len(need) incorrect (%d != 0)", len(fs))
 	}
 
 	newFile := protocol.FileInfo{
@@ -309,8 +309,8 @@ func TestForgetNode(t *testing.T) {
 	if l1, l2 := len(m.global), len(fs)+1; l1 != l2 {
 		t.Errorf("Model len(global) incorrect (%d != %d)", l1, l2)
 	}
-	if l1, l2 := len(m.need), 1; l1 != l2 {
+	if fs, _ := m.NeedFiles(); len(fs) != 1 {
-		t.Errorf("Model len(need) incorrect (%d != %d)", l1, l2)
+		t.Errorf("Model len(need) incorrect (%d != 1)", len(fs))
 	}
 
 	m.Close("42", nil)
@@ -321,8 +321,17 @@ func TestForgetNode(t *testing.T) {
 	if l1, l2 := len(m.global), len(fs); l1 != l2 {
 		t.Errorf("Model len(global) incorrect (%d != %d)", l1, l2)
 	}
-	if l1, l2 := len(m.need), 0; l1 != l2 {
+
-		t.Errorf("Model len(need) incorrect (%d != %d)", l1, l2)
+	if fs, _ := m.NeedFiles(); len(fs) != 1 {
+		t.Errorf("Model len(need) incorrect (%d != 1)", len(fs))
+	}
+	// The file will be removed from the need list when we notice there are no nodes that can provide it
+	_, ok := m.fq.Get("42")
+	if ok {
+		t.Errorf("Unexpected successfull Get()")
+	}
+	if fs, _ := m.NeedFiles(); len(fs) != 0 {
+		t.Errorf("Model len(need) incorrect (%d != 0)", len(fs))
 	}
 }
 
@@ -465,7 +474,7 @@ func (f FakeConnection) ID() string {
 
 func (FakeConnection) Index([]protocol.FileInfo) {}
 
-func (f FakeConnection) Request(name string, offset uint64, size uint32, hash []byte) ([]byte, error) {
+func (f FakeConnection) Request(name string, offset int64, size uint32, hash []byte) ([]byte, error) {
 	return f.requestData, nil
 }
 

model/walk.go

@@ -26,11 +26,16 @@ type File struct {
 
 func (f File) Size() (bytes int) {
 	for _, b := range f.Blocks {
-		bytes += int(b.Length)
+		bytes += int(b.Size)
 	}
 	return
 }
 
+func (f File) String() string {
+	return fmt.Sprintf("File{Name:%q, Flags:0x%x, Modified:%d, Version:%d:, NumBlocks:%d}",
+		f.Name, f.Flags, f.Modified, f.Version, len(f.Blocks))
+}
+
 func (f File) Equals(o File) bool {
 	return f.Modified == o.Modified && f.Version == o.Version
 }

protocol/common_test.go

@@ -5,7 +5,7 @@ import "io"
 type TestModel struct {
 	data   []byte
 	name   string
-	offset uint64
+	offset int64
 	size   uint32
 	hash   []byte
 	closed bool
@@ -17,7 +17,7 @@ func (t *TestModel) Index(nodeID string, files []FileInfo) {
 func (t *TestModel) IndexUpdate(nodeID string, files []FileInfo) {
 }
 
-func (t *TestModel) Request(nodeID, name string, offset uint64, size uint32, hash []byte) ([]byte, error) {
+func (t *TestModel) Request(nodeID, name string, offset int64, size uint32, hash []byte) ([]byte, error) {
 	t.name = name
 	t.offset = offset
 	t.size = size

protocol/messages.go

@@ -4,7 +4,7 @@ import "io"
 
 type request struct {
 	name   string
-	offset uint64
+	offset int64
 	size   uint32
 	hash   []byte
 }
@@ -42,7 +42,7 @@ func (w *marshalWriter) writeIndex(idx []FileInfo) {
 		w.writeUint32(f.Version)
 		w.writeUint32(uint32(len(f.Blocks)))
 		for _, b := range f.Blocks {
-			w.writeUint32(b.Length)
+			w.writeUint32(b.Size)
 			w.writeBytes(b.Hash)
 		}
 	}
@@ -56,7 +56,7 @@ func WriteIndex(w io.Writer, idx []FileInfo) (int, error) {
 
 func (w *marshalWriter) writeRequest(r request) {
 	w.writeString(r.name)
-	w.writeUint64(r.offset)
+	w.writeUint64(uint64(r.offset))
 	w.writeUint32(r.size)
 	w.writeBytes(r.hash)
 }
@@ -82,7 +82,7 @@ func (r *marshalReader) readIndex() []FileInfo {
 			nblocks := r.readUint32()
 			blocks := make([]BlockInfo, nblocks)
 			for j := range blocks {
-				blocks[j].Length = r.readUint32()
+				blocks[j].Size = r.readUint32()
 				blocks[j].Hash = r.readBytes()
 			}
 			files[i].Blocks = blocks
@@ -100,7 +100,7 @@ func ReadIndex(r io.Reader) ([]FileInfo, error) {
 func (r *marshalReader) readRequest() request {
 	var req request
 	req.name = r.readString()
-	req.offset = r.readUint64()
+	req.offset = int64(r.readUint64())
 	req.size = r.readUint32()
 	req.hash = r.readBytes()
 	return req

protocol/messages_test.go

@@ -46,7 +46,7 @@ func TestIndex(t *testing.T) {
 }
 
 func TestRequest(t *testing.T) {
-	f := func(name string, offset uint64, size uint32, hash []byte) bool {
+	f := func(name string, offset int64, size uint32, hash []byte) bool {
 		var buf = new(bytes.Buffer)
 		var req = request{name, offset, size, hash}
 		var wr = marshalWriter{w: buf}

protocol/protocol.go

@@ -34,7 +34,7 @@ type FileInfo struct {
 }
 
 type BlockInfo struct {
-	Length uint32
+	Size uint32
 	Hash []byte
 }
 
@@ -44,7 +44,7 @@ type Model interface {
 	// An index update was received from the peer node
 	IndexUpdate(nodeID string, files []FileInfo)
 	// A request was made by the peer node
-	Request(nodeID, name string, offset uint64, size uint32, hash []byte) ([]byte, error)
+	Request(nodeID, name string, offset int64, size uint32, hash []byte) ([]byte, error)
 	// The peer node closed the connection
 	Close(nodeID string, err error)
 }
@@ -150,7 +150,7 @@ func (c *Connection) Index(idx []FileInfo) {
 }
 
 // Request returns the bytes for the specified block after fetching them from the connected peer.
-func (c *Connection) Request(name string, offset uint64, size uint32, hash []byte) ([]byte, error) {
+func (c *Connection) Request(name string, offset int64, size uint32, hash []byte) ([]byte, error) {
 	c.Lock()
 	if c.closed {
 		c.Unlock()