Merge pull request #896 from erizocosmico/feature/new-index-decoder

plumbing/format/idxfile: add new Index and MemoryIndex

1 files changed, 48 insertions, 53 deletions

diff --git a/plumbing/format/idxfile/encoder.go b/plumbing/format/idxfile/encoder.go
index 40abfb8..55df466 100644
--- a/plumbing/format/idxfile/encoder.go
+++ b/plumbing/format/idxfile/encoder.go
@@ -4,12 +4,11 @@ import (
 	"crypto/sha1"
 	"hash"
 	"io"
-	"sort"
 
 	"gopkg.in/src-d/go-git.v4/utils/binary"
 )
 
-// Encoder writes Idxfile structs to an output stream.
+// Encoder writes MemoryIndex structs to an output stream.
 type Encoder struct {
 	io.Writer
 	hash hash.Hash
@@ -22,11 +21,9 @@ func NewEncoder(w io.Writer) *Encoder {
 	return &Encoder{mw, h}
 }
 
-// Encode encodes an Idxfile to the encoder writer.
-func (e *Encoder) Encode(idx *Idxfile) (int, error) {
-	idx.Entries.Sort()
-
-	flow := []func(*Idxfile) (int, error){
+// Encode encodes an MemoryIndex to the encoder writer.
+func (e *Encoder) Encode(idx *MemoryIndex) (int, error) {
+	flow := []func(*MemoryIndex) (int, error){
 		e.encodeHeader,
 		e.encodeFanout,
 		e.encodeHashes,
@@ -48,7 +45,7 @@ func (e *Encoder) Encode(idx *Idxfile) (int, error) {
 	return sz, nil
 }
 
-func (e *Encoder) encodeHeader(idx *Idxfile) (int, error) {
+func (e *Encoder) encodeHeader(idx *MemoryIndex) (int, error) {
 	c, err := e.Write(idxHeader)
 	if err != nil {
 		return c, err
@@ -57,75 +54,81 @@ func (e *Encoder) encodeHeader(idx *Idxfile) (int, error) {
 	return c + 4, binary.WriteUint32(e, idx.Version)
 }
 
-func (e *Encoder) encodeFanout(idx *Idxfile) (int, error) {
-	fanout := idx.calculateFanout()
-	for _, c := range fanout {
+func (e *Encoder) encodeFanout(idx *MemoryIndex) (int, error) {
+	for _, c := range idx.Fanout {
 		if err := binary.WriteUint32(e, c); err != nil {
 			return 0, err
 		}
 	}
 
-	return 1024, nil
+	return fanout * 4, nil
 }
 
-func (e *Encoder) encodeHashes(idx *Idxfile) (int, error) {
-	sz := 0
-	for _, ent := range idx.Entries {
-		i, err := e.Write(ent.Hash[:])
-		sz += i
+func (e *Encoder) encodeHashes(idx *MemoryIndex) (int, error) {
+	var size int
+	for k := 0; k < fanout; k++ {
+		pos := idx.FanoutMapping[k]
+		if pos == noMapping {
+			continue
+		}
 
+		n, err := e.Write(idx.Names[pos])
 		if err != nil {
-			return sz, err
+			return size, err
 		}
+		size += n
 	}
-
-	return sz, nil
+	return size, nil
 }
 
-func (e *Encoder) encodeCRC32(idx *Idxfile) (int, error) {
-	sz := 0
-	for _, ent := range idx.Entries {
-		err := binary.Write(e, ent.CRC32)
-		sz += 4
+func (e *Encoder) encodeCRC32(idx *MemoryIndex) (int, error) {
+	var size int
+	for k := 0; k < fanout; k++ {
+		pos := idx.FanoutMapping[k]
+		if pos == noMapping {
+			continue
+		}
 
+		n, err := e.Write(idx.Crc32[pos])
 		if err != nil {
-			return sz, err
+			return size, err
 		}
+
+		size += n
 	}
 
-	return sz, nil
+	return size, nil
 }
 
-func (e *Encoder) encodeOffsets(idx *Idxfile) (int, error) {
-	sz := 0
-
-	var o64bits []uint64
-	for _, ent := range idx.Entries {
-		o := ent.Offset
-		if o > offsetLimit {
-			o64bits = append(o64bits, o)
-			o = offsetLimit + uint64(len(o64bits))
+func (e *Encoder) encodeOffsets(idx *MemoryIndex) (int, error) {
+	var size int
+	for k := 0; k < fanout; k++ {
+		pos := idx.FanoutMapping[k]
+		if pos == noMapping {
+			continue
 		}
 
-		if err := binary.WriteUint32(e, uint32(o)); err != nil {
-			return sz, err
+		n, err := e.Write(idx.Offset32[pos])
+		if err != nil {
+			return size, err
 		}
 
-		sz += 4
+		size += n
 	}
 
-	for _, o := range o64bits {
-		if err := binary.WriteUint64(e, o); err != nil {
-			return sz, err
+	if len(idx.Offset64) > 0 {
+		n, err := e.Write(idx.Offset64)
+		if err != nil {
+			return size, err
 		}
 
-		sz += 8
+		size += n
 	}
 
-	return sz, nil
+	return size, nil
 }
 
-func (e *Encoder) encodeChecksums(idx *Idxfile) (int, error) {
+func (e *Encoder) encodeChecksums(idx *MemoryIndex) (int, error) {
 	if _, err := e.Write(idx.PackfileChecksum[:]); err != nil {
 		return 0, err
 	}
@@ -137,11 +140,3 @@ func (e *Encoder) encodeChecksums(idx *Idxfile) (int, error) {
 
 	return 40, nil
 }
-
-// EntryList implements sort.Interface allowing sorting in increasing order.
-type EntryList []*Entry
-
-func (p EntryList) Len() int           { return len(p) }
-func (p EntryList) Less(i, j int) bool { return p[i].Hash.String() < p[j].Hash.String() }
-func (p EntryList) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
-func (p EntryList) Sort()              { sort.Sort(p) }