Refactor StorageMap to BlobList

Makefile

@@ -1,7 +1,6 @@
 .PHONY: clean all test
 
 test:
-	go test -race ./...
 	for dir in cmd/* ; do \
 		(cd "$$dir"; go build -race) \
 	done

archiver.go

@@ -20,8 +20,7 @@ type Archiver struct {
 	key *Key
 	ch  *ContentHandler
 
-	m    sync.Mutex
+	bl *BlobList // blobs used for the current snapshot
-	smap *StorageMap // blobs used for the current snapshot
 
 	fileToken chan struct{}
 
@@ -63,7 +62,7 @@ func NewArchiver(be backend.Server, key *Key) (*Archiver, error) {
 	// do nothing
 	arch.ScannerUpdate = func(Stats) {}
 
-	arch.smap = NewStorageMap()
+	arch.bl = NewBlobList()
 	arch.ch, err = NewContentHandler(be, key)
 	if err != nil {
 		return nil, err
@@ -86,30 +85,26 @@ func (arch *Archiver) saveUpdate(stats Stats) {
 	}
 }
 
-func (arch *Archiver) Save(t backend.Type, data []byte) (*Blob, error) {
+func (arch *Archiver) Save(t backend.Type, data []byte) (Blob, error) {
 	blob, err := arch.ch.Save(t, data)
 	if err != nil {
-		return nil, err
+		return Blob{}, err
 	}
 
 	// store blob in storage map for current snapshot
-	arch.m.Lock()
+	arch.bl.Insert(blob)
-	defer arch.m.Unlock()
-	arch.smap.Insert(blob)
 
 	return blob, nil
 }
 
-func (arch *Archiver) SaveJSON(t backend.Type, item interface{}) (*Blob, error) {
+func (arch *Archiver) SaveJSON(t backend.Type, item interface{}) (Blob, error) {
 	blob, err := arch.ch.SaveJSON(t, item)
 	if err != nil {
-		return nil, err
+		return Blob{}, err
 	}
 
 	// store blob in storage map for current snapshot
-	arch.m.Lock()
+	arch.bl.Insert(blob)
-	defer arch.m.Unlock()
-	arch.smap.Insert(blob)
 
 	return blob, nil
 }
@@ -168,9 +163,7 @@ func (arch *Archiver) SaveFile(node *Node) error {
 	node.Content = make([]backend.ID, len(blobs))
 	for i, blob := range blobs {
 		node.Content[i] = blob.ID
-		arch.m.Lock()
+		arch.bl.Insert(blob)
-		arch.smap.Insert(blob)
-		arch.m.Unlock()
 	}
 
 	return err
@@ -258,14 +251,14 @@ func (arch *Archiver) LoadTree(path string) (*Tree, error) {
 	return &Tree{node}, nil
 }
 
-func (arch *Archiver) saveTree(t *Tree) (*Blob, error) {
+func (arch *Archiver) saveTree(t *Tree) (Blob, error) {
 	var wg sync.WaitGroup
 
 	for _, node := range *t {
 		if node.Tree != nil && node.Subtree == nil {
 			b, err := arch.saveTree(node.Tree)
 			if err != nil {
-				return nil, err
+				return Blob{}, err
 			}
 			node.Subtree = b.ID
 			arch.saveUpdate(Stats{Directories: 1})
@@ -294,7 +287,7 @@ func (arch *Archiver) saveTree(t *Tree) (*Blob, error) {
 
 	blob, err := arch.SaveJSON(backend.Tree, t)
 	if err != nil {
-		return nil, err
+		return Blob{}, err
 	}
 
 	return blob, nil
@@ -311,7 +304,7 @@ func (arch *Archiver) Snapshot(dir string, t *Tree) (*Snapshot, backend.ID, erro
 	sn.Content = blob.ID
 
 	// save snapshot
-	sn.StorageMap = arch.smap
+	sn.BlobList = arch.bl
 	blob, err = arch.SaveJSON(backend.Snapshot, sn)
 	if err != nil {
 		return nil, nil, err

backend/id.go

@@ -47,6 +47,11 @@ func (id ID) EqualString(other string) (bool, error) {
 	return id.Equal(ID(s)), nil
 }
 
+// Compare compares this ID to another one, returning -1, 0, or 1.
+func (id ID) Compare(other ID) int {
+	return bytes.Compare(other, id)
+}
+
 func (id ID) MarshalJSON() ([]byte, error) {
 	return json.Marshal(id.String())
 }

bloblist.go

@@ -0,0 +1,99 @@
+package khepri
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"sort"
+	"sync"
+)
+
+type BlobList struct {
+	list []Blob
+	m    sync.Mutex
+}
+
+var ErrBlobNotFound = errors.New("Blob not found")
+
+func NewBlobList() *BlobList {
+	return &BlobList{
+		list: []Blob{},
+	}
+}
+
+func (bl *BlobList) find(blob Blob) (int, Blob, error) {
+	pos := sort.Search(len(bl.list), func(i int) bool {
+		return blob.ID.Compare(bl.list[i].ID) >= 0
+	})
+
+	if pos < len(bl.list) && blob.ID.Compare(bl.list[pos].ID) == 0 {
+		return pos, bl.list[pos], nil
+	}
+
+	return pos, Blob{}, ErrBlobNotFound
+}
+
+func (bl *BlobList) Find(blob Blob) (Blob, error) {
+	bl.m.Lock()
+	defer bl.m.Unlock()
+
+	_, blob, err := bl.find(blob)
+	return blob, err
+}
+
+func (bl *BlobList) Merge(other *BlobList) {
+	bl.m.Lock()
+	defer bl.m.Unlock()
+	other.m.Lock()
+	defer other.m.Unlock()
+
+	for _, blob := range other.list {
+		bl.insert(blob)
+	}
+}
+
+func (bl *BlobList) insert(blob Blob) {
+	pos, _, err := bl.find(blob)
+	if err == nil {
+		// already present
+		return
+	}
+
+	// insert blob
+	// https://code.google.com/p/go-wiki/wiki/bliceTricks
+	bl.list = append(bl.list, Blob{})
+	copy(bl.list[pos+1:], bl.list[pos:])
+	bl.list[pos] = blob
+}
+
+func (bl *BlobList) Insert(blob Blob) {
+	bl.m.Lock()
+	defer bl.m.Unlock()
+
+	bl.insert(blob)
+}
+
+func (bl BlobList) MarshalJSON() ([]byte, error) {
+	return json.Marshal(bl.list)
+}
+
+func (bl *BlobList) UnmarshalJSON(data []byte) error {
+	return json.Unmarshal(data, &bl.list)
+}
+
+// Compare compares two blobs by comparing the ID and the size. It returns -1,
+// 0, or 1.
+func (blob Blob) Compare(other Blob) int {
+	if res := bytes.Compare(other.ID, blob.ID); res != 0 {
+		return res
+	}
+
+	if blob.Size < other.Size {
+		return -1
+	}
+	if blob.Size > other.Size {
+		return 1
+	}
+
+	return 0
+}

bloblist_test.go

@@ -0,0 +1,137 @@
+package khepri_test
+
+import (
+	"crypto/rand"
+	"encoding/json"
+	"flag"
+	"io"
+	mrand "math/rand"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/fd0/khepri"
+)
+
+const backendIDSize = 8
+
+var maxWorkers = flag.Uint("workers", 100, "number of workers to test BlobList concurrent access against")
+
+func randomID() []byte {
+	buf := make([]byte, backendIDSize)
+	_, err := io.ReadFull(rand.Reader, buf)
+	if err != nil {
+		panic(err)
+	}
+	return buf
+}
+
+func newBlob() khepri.Blob {
+	return khepri.Blob{ID: randomID(), Size: uint64(mrand.Uint32())}
+}
+
+// Test basic functionality
+func TestBlobList(t *testing.T) {
+	bl := khepri.NewBlobList()
+
+	b := newBlob()
+	bl.Insert(b)
+
+	for i := 0; i < 1000; i++ {
+		bl.Insert(newBlob())
+	}
+
+	b2, err := bl.Find(khepri.Blob{ID: b.ID})
+	ok(t, err)
+	assert(t, b2.Compare(b) == 0, "items are not equal: want %v, got %v", b, b2)
+
+	bl2 := khepri.NewBlobList()
+	for i := 0; i < 1000; i++ {
+		bl.Insert(newBlob())
+	}
+
+	b2, err = bl2.Find(b)
+	assert(t, err != nil, "found ID in khepri that was never inserted: %v", b2)
+
+	bl2.Merge(bl)
+
+	b2, err = bl2.Find(b)
+
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if b.Compare(b2) != 0 {
+		t.Fatalf("items are not equal: want %v, got %v", b, b2)
+	}
+}
+
+// Test JSON encode/decode
+func TestBlobListJSON(t *testing.T) {
+	bl := khepri.NewBlobList()
+	b := khepri.Blob{ID: []byte{1, 2, 3, 4}}
+	bl.Insert(b)
+
+	b2, err := bl.Find(b)
+	ok(t, err)
+	assert(t, b2.Compare(b) == 0, "items are not equal: want %v, got %v", b, b2)
+
+	buf, err := json.Marshal(bl)
+	ok(t, err)
+
+	bl2 := khepri.BlobList{}
+	json.Unmarshal(buf, &bl2)
+
+	b2, err = bl2.Find(b)
+	ok(t, err)
+	assert(t, b2.Compare(b) == 0, "items are not equal: want %v, got %v", b, b2)
+
+	buf, err = json.Marshal(bl2)
+	ok(t, err)
+}
+
+// random insert/find access by several goroutines
+func TestBlobListRandom(t *testing.T) {
+	var wg sync.WaitGroup
+
+	worker := func(bl *khepri.BlobList) {
+		defer wg.Done()
+
+		b := newBlob()
+		bl.Insert(b)
+
+		for i := 0; i < 200; i++ {
+			bl.Insert(newBlob())
+		}
+
+		d := time.Duration(mrand.Intn(10)*100) * time.Millisecond
+		time.Sleep(d)
+
+		for i := 0; i < 100; i++ {
+			b2, err := bl.Find(b)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			if b.Compare(b2) != 0 {
+				t.Fatalf("items are not equal: want %v, got %v", b, b2)
+			}
+		}
+
+		bl2 := khepri.NewBlobList()
+		for i := 0; i < 200; i++ {
+			bl2.Insert(newBlob())
+		}
+
+		bl2.Merge(bl)
+	}
+
+	bl := khepri.NewBlobList()
+
+	for i := 0; uint(i) < *maxWorkers; i++ {
+		wg.Add(1)
+		go worker(bl)
+	}
+
+	wg.Wait()
+}

contenthandler.go

@@ -3,7 +3,7 @@ package khepri
 import (
 	"encoding/json"
 	"errors"
-	"sync"
+	"fmt"
 
 	"github.com/fd0/khepri/backend"
 )
@@ -12,8 +12,7 @@ type ContentHandler struct {
 	be  backend.Server
 	key *Key
 
-	m       sync.Mutex
+	bl *BlobList
-	content *StorageMap
 }
 
 // NewContentHandler creates a new content handler.
@@ -21,7 +20,7 @@ func NewContentHandler(be backend.Server, key *Key) (*ContentHandler, error) {
 	ch := &ContentHandler{
 		be:  be,
 		key: key,
-		content: NewStorageMap(),
+		bl:  NewBlobList(),
 	}
 
 	return ch, nil
@@ -34,9 +33,8 @@ func (ch *ContentHandler) LoadSnapshot(id backend.ID) (*Snapshot, error) {
 		return nil, err
 	}
 
-	ch.m.Lock()
+	ch.bl.Merge(sn.BlobList)
-	defer ch.m.Unlock()
+
-	ch.content.Merge(sn.StorageMap)
 	return sn, nil
 }
 
@@ -50,9 +48,7 @@ func (ch *ContentHandler) LoadAllSnapshots() error {
 			return
 		}
 
-		ch.m.Lock()
+		ch.bl.Merge(sn.BlobList)
-		defer ch.m.Unlock()
-		ch.content.Merge(sn.StorageMap)
 	})
 	if err != nil {
 		return err
@@ -63,20 +59,18 @@ func (ch *ContentHandler) LoadAllSnapshots() error {
 
 // Save encrypts data and stores it to the backend as type t. If the data was
 // already saved before, the blob is returned.
-func (ch *ContentHandler) Save(t backend.Type, data []byte) (*Blob, error) {
+func (ch *ContentHandler) Save(t backend.Type, data []byte) (Blob, error) {
 	// compute plaintext hash
 	id := backend.Hash(data)
 
 	// test if the hash is already in the backend
-	ch.m.Lock()
+	blob, err := ch.bl.Find(Blob{ID: id})
-	defer ch.m.Unlock()
+	if err == nil {
-	blob := ch.content.Find(id)
-	if blob != nil {
 		return blob, nil
 	}
 
 	// else create a new blob
-	blob = &Blob{
+	blob = Blob{
 		ID:   id,
 		Size: uint64(len(data)),
 	}
@@ -84,30 +78,30 @@ func (ch *ContentHandler) Save(t backend.Type, data []byte) (*Blob, error) {
 	// encrypt blob
 	ciphertext, err := ch.key.Encrypt(data)
 	if err != nil {
-		return nil, err
+		return Blob{}, err
 	}
 
 	// save blob
 	sid, err := ch.be.Create(t, ciphertext)
 	if err != nil {
-		return nil, err
+		return Blob{}, err
 	}
 
 	blob.Storage = sid
 	blob.StorageSize = uint64(len(ciphertext))
 
 	// insert blob into the storage map
-	ch.content.Insert(blob)
+	ch.bl.Insert(blob)
 
 	return blob, nil
 }
 
 // SaveJSON serialises item as JSON and uses Save() to store it to the backend as type t.
-func (ch *ContentHandler) SaveJSON(t backend.Type, item interface{}) (*Blob, error) {
+func (ch *ContentHandler) SaveJSON(t backend.Type, item interface{}) (Blob, error) {
 	// convert to json
 	data, err := json.Marshal(item)
 	if err != nil {
-		return nil, err
+		return Blob{}, err
 	}
 
 	// compress and save data
@@ -133,11 +127,9 @@ func (ch *ContentHandler) Load(t backend.Type, id backend.ID) ([]byte, error) {
 	}
 
 	// lookup storage hash
-	ch.m.Lock()
+	blob, err := ch.bl.Find(Blob{ID: id})
-	defer ch.m.Unlock()
+	if err != nil {
-	blob := ch.content.Find(id)
+		return nil, fmt.Errorf("Storage ID %s not found", id)
-	if blob == nil {
-		return nil, errors.New("Storage ID not found")
 	}
 
 	// load data

restorer.go

@@ -30,12 +30,12 @@ func NewRestorer(be backend.Server, key *Key, snid backend.ID) (*Restorer, error
 	var err error
 	r.ch, err = NewContentHandler(be, key)
 	if err != nil {
-		return nil, err
+		return nil, arrar.Annotate(err, "create contenthandler for restorer")
 	}
 
 	r.sn, err = r.ch.LoadSnapshot(snid)
 	if err != nil {
-		return nil, err
+		return nil, arrar.Annotate(err, "load snapshot for restorer")
 	}
 
 	// abort on all errors

snapshot.go

@@ -13,7 +13,7 @@ import (
 type Snapshot struct {
 	Time     time.Time  `json:"time"`
 	Content  backend.ID `json:"content"`
-	StorageMap *StorageMap `json:"map"`
+	BlobList *BlobList  `json:"blobs"`
 	Dir      string     `json:"dir"`
 	Hostname string     `json:"hostname,omitempty"`
 	Username string     `json:"username,omitempty"`

storagemap.go

@@ -1,51 +0,0 @@
-package khepri
-
-import (
-	"bytes"
-	"sort"
-
-	"github.com/fd0/khepri/backend"
-)
-
-type StorageMap Blobs
-
-func NewStorageMap() *StorageMap {
-	return &StorageMap{}
-}
-
-func (m StorageMap) find(id backend.ID) (int, *Blob) {
-	i := sort.Search(len(m), func(i int) bool {
-		return bytes.Compare(m[i].ID, id) >= 0
-	})
-
-	if i < len(m) && bytes.Equal(m[i].ID, id) {
-		return i, m[i]
-	}
-
-	return i, nil
-}
-
-func (m StorageMap) Find(id backend.ID) *Blob {
-	_, blob := m.find(id)
-	return blob
-}
-
-func (m *StorageMap) Insert(blob *Blob) {
-	pos, b := m.find(blob.ID)
-	if b != nil {
-		// already present
-		return
-	}
-
-	// insert blob
-	// https://code.google.com/p/go-wiki/wiki/SliceTricks
-	*m = append(*m, nil)
-	copy((*m)[pos+1:], (*m)[pos:])
-	(*m)[pos] = blob
-}
-
-func (m *StorageMap) Merge(sm *StorageMap) {
-	for _, blob := range *sm {
-		m.Insert(blob)
-	}
-}

tree.go

@@ -46,7 +46,7 @@ type Blob struct {
 	StorageSize uint64     `json:"ssize,omitempty"` // encrypted Size
 }
 
-type Blobs []*Blob
+type Blobs []Blob
 
 func (n Node) String() string {
 	switch n.Type {