Merge pull request #20 from bk2204/sha256

Add support for SHA-256

Author: bk2204

backend.go

@@ -2,39 +2,36 @@ package gitobj
 
 import (
 	"bufio"
+	"hash"
 	"io"
 	"os"
 	"path"
 	"regexp"
 	"strconv"
 	"strings"
 
-	"github.com/git-lfs/gitobj/pack"
-	"github.com/git-lfs/gitobj/storage"
+	"github.com/git-lfs/gitobj/v2/pack"
+	"github.com/git-lfs/gitobj/v2/storage"
 )
 
-// NewFilesystemBackend initializes a new filesystem-based backend.
-func NewFilesystemBackend(root, tmp string) (storage.Backend, error) {
-	return NewFilesystemBackendWithAlternates(root, tmp, "")
-}
-
-// NewFilesystemBackendWithAlternates initializes a new filesystem-based
-// backend, optionally with additional alternates as specified in the
+// NewFilesystemBackend initializes a new filesystem-based backend,
+// optionally with additional alternates as specified in the
 // `alternates` variable. The syntax is that of the Git environment variable
-// GIT_ALTERNATE_OBJECT_DIRECTORIES.
-func NewFilesystemBackendWithAlternates(root, tmp, alternates string) (storage.Backend, error) {
+// GIT_ALTERNATE_OBJECT_DIRECTORIES.  The hash algorithm used is specified by
+// the algo parameter.
+func NewFilesystemBackend(root, tmp, alternates string, algo hash.Hash) (storage.Backend, error) {
 	fsobj := newFileStorer(root, tmp)
-	packs, err := pack.NewStorage(root)
+	packs, err := pack.NewStorage(root, algo)
 	if err != nil {
 		return nil, err
 	}
 
-	storage, err := findAllBackends(fsobj, packs, root)
+	storage, err := findAllBackends(fsobj, packs, root, algo)
 	if err != nil {
 		return nil, err
 	}
 
-	storage, err = addAlternatesFromEnvironment(storage, alternates)
+	storage, err = addAlternatesFromEnvironment(storage, alternates, algo)
 	if err != nil {
 		return nil, err
 	}
@@ -45,7 +42,7 @@ func NewFilesystemBackendWithAlternates(root, tmp, alternates string) (storage.B
 	}, nil
 }
 
-func findAllBackends(mainLoose *fileStorer, mainPacked *pack.Storage, root string) ([]storage.Storage, error) {
+func findAllBackends(mainLoose *fileStorer, mainPacked *pack.Storage, root string, algo hash.Hash) ([]storage.Storage, error) {
 	storage := make([]storage.Storage, 2)
 	storage[0] = mainLoose
 	storage[1] = mainPacked
@@ -61,7 +58,7 @@ func findAllBackends(mainLoose *fileStorer, mainPacked *pack.Storage, root strin
 
 	scanner := bufio.NewScanner(f)
 	for scanner.Scan() {
-		storage, err = addAlternateDirectory(storage, scanner.Text())
+		storage, err = addAlternateDirectory(storage, scanner.Text(), algo)
 		if err != nil {
 			return nil, err
 		}
@@ -74,24 +71,24 @@ func findAllBackends(mainLoose *fileStorer, mainPacked *pack.Storage, root strin
 	return storage, nil
 }
 
-func addAlternateDirectory(s []storage.Storage, dir string) ([]storage.Storage, error) {
+func addAlternateDirectory(s []storage.Storage, dir string, algo hash.Hash) ([]storage.Storage, error) {
 	s = append(s, newFileStorer(dir, ""))
-	pack, err := pack.NewStorage(dir)
+	pack, err := pack.NewStorage(dir, algo)
 	if err != nil {
 		return s, err
 	}
 	s = append(s, pack)
 	return s, nil
 }
 
-func addAlternatesFromEnvironment(s []storage.Storage, env string) ([]storage.Storage, error) {
+func addAlternatesFromEnvironment(s []storage.Storage, env string, algo hash.Hash) ([]storage.Storage, error) {
 	if len(env) == 0 {
 		return s, nil
 	}
 
 	for _, dir := range splitAlternateString(env, alternatesSeparator) {
 		var err error
-		s, err = addAlternateDirectory(s, dir)
+		s, err = addAlternateDirectory(s, dir, algo)
 		if err != nil {
 			return nil, err
 		}

blob.go

@@ -3,6 +3,7 @@ package gitobj
 import (
 	"bytes"
 	"fmt"
+	"hash"
 	"io"
 	"os"
 )
@@ -75,7 +76,7 @@ func (b *Blob) Type() ObjectType { return BlobObjectType }
 // stream, which is always zero.
 //
 // If any errors are encountered while reading the blob, they will be returned.
-func (b *Blob) Decode(r io.Reader, size int64) (n int, err error) {
+func (b *Blob) Decode(hash hash.Hash, r io.Reader, size int64) (n int, err error) {
 	b.Size = size
 	b.Contents = io.LimitReader(r, size)
 

blob_test.go

@@ -2,6 +2,7 @@ package gitobj
 
 import (
 	"bytes"
+	"crypto/sha1"
 	"errors"
 	"io/ioutil"
 	"strings"
@@ -48,7 +49,7 @@ func TestBlobDecoding(t *testing.T) {
 	from := strings.NewReader(contents)
 
 	b := new(Blob)
-	n, err := b.Decode(from, int64(len(contents)))
+	n, err := b.Decode(sha1.New(), from, int64(len(contents)))
 
 	assert.Equal(t, 0, n)
 	assert.Nil(t, err)

commit.go

@@ -5,6 +5,7 @@ import (
 	"bytes"
 	"encoding/hex"
 	"fmt"
+	"hash"
 	"io"
 	"strings"
 	"time"
@@ -91,12 +92,12 @@ func (c *Commit) Type() ObjectType { return CommitObjectType }
 //
 // If any error was encountered along the way, that will be returned, along with
 // the number of bytes read up to that point.
-func (c *Commit) Decode(from io.Reader, size int64) (n int, err error) {
+func (c *Commit) Decode(hash hash.Hash, from io.Reader, size int64) (n int, err error) {
 	var finishedHeaders bool
 	var messageParts []string
 
 	s := bufio.NewScanner(from)
-	s.Buffer(nil, 1024 * 1024)
+	s.Buffer(nil, 1024*1024)
 	for s.Scan() {
 		text := s.Text()
 		n = n + len(text+"\n")

commit_test.go

@@ -2,6 +2,7 @@ package gitobj
 
 import (
 	"bytes"
+	"crypto/sha1"
 	"encoding/hex"
 	"fmt"
 	"io"
@@ -77,7 +78,7 @@ func TestCommitDecoding(t *testing.T) {
 	flen := from.Len()
 
 	commit := new(Commit)
-	n, err := commit.Decode(from, int64(flen))
+	n, err := commit.Decode(sha1.New(), from, int64(flen))
 
 	assert.Nil(t, err)
 	assert.Equal(t, flen, n)
@@ -107,7 +108,7 @@ func TestCommitDecodingWithEmptyName(t *testing.T) {
 	flen := from.Len()
 
 	commit := new(Commit)
-	n, err := commit.Decode(from, int64(flen))
+	n, err := commit.Decode(sha1.New(), from, int64(flen))
 
 	assert.Nil(t, err)
 	assert.Equal(t, flen, n)
@@ -118,10 +119,10 @@ func TestCommitDecodingWithEmptyName(t *testing.T) {
 }
 
 func TestCommitDecodingWithLargeCommitMessage(t *testing.T) {
-	message := "This message text is, with newline, exactly 64 characters long. ";
+	message := "This message text is, with newline, exactly 64 characters long. "
 	// This message will be exactly 1 MiB in size when part of the commit.
-	longMessage := strings.Repeat(message, (1024 * 1024 / 64) - 1)
-	longMessage += strings.TrimSpace(message);
+	longMessage := strings.Repeat(message, (1024*1024/64)-1)
+	longMessage += strings.TrimSpace(message)
 
 	author := &Signature{Name: "", Email: "john@example.com", When: time.Now()}
 	committer := &Signature{Name: "", Email: "jane@example.com", When: time.Now()}
@@ -138,7 +139,7 @@ func TestCommitDecodingWithLargeCommitMessage(t *testing.T) {
 	flen := from.Len()
 
 	commit := new(Commit)
-	n, err := commit.Decode(from, int64(flen))
+	n, err := commit.Decode(sha1.New(), from, int64(flen))
 
 	assert.Nil(t, err)
 	assert.Equal(t, flen, n)
@@ -164,7 +165,7 @@ func TestCommitDecodingWithMessageKeywordPrefix(t *testing.T) {
 	flen := from.Len()
 
 	commit := new(Commit)
-	n, err := commit.Decode(from, int64(flen))
+	n, err := commit.Decode(sha1.New(), from, int64(flen))
 
 	assert.NoError(t, err)
 	assert.Equal(t, flen, n)
@@ -191,7 +192,7 @@ func TestCommitDecodingWithWhitespace(t *testing.T) {
 	flen := from.Len()
 
 	commit := new(Commit)
-	n, err := commit.Decode(from, int64(flen))
+	n, err := commit.Decode(sha1.New(), from, int64(flen))
 
 	assert.NoError(t, err)
 	assert.Equal(t, flen, n)
@@ -221,7 +222,7 @@ func TestCommitDecodingMultilineHeader(t *testing.T) {
 	flen := from.Len()
 
 	commit := new(Commit)
-	n, err := commit.Decode(from, int64(flen))
+	n, err := commit.Decode(sha1.New(), from, int64(flen))
 
 	require.Nil(t, err)
 	require.Equal(t, flen, n)

file_storer.go

@@ -8,7 +8,7 @@ import (
 	"os"
 	"path/filepath"
 
-	"github.com/git-lfs/gitobj/errors"
+	"github.com/git-lfs/gitobj/v2/errors"
 )
 
 // fileStorer implements the storer interface by writing to the .git/objects

go.mod

@@ -1,4 +1,4 @@
-module github.com/git-lfs/gitobj
+module github.com/git-lfs/gitobj/v2
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect

memory_storer.go

@@ -6,7 +6,7 @@ import (
 	"io"
 	"sync"
 
-	"github.com/git-lfs/gitobj/errors"
+	"github.com/git-lfs/gitobj/v2/errors"
 )
 
 // memoryStorer is an implementation of the storer interface that holds data for

memory_storer_test.go

@@ -8,7 +8,7 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/git-lfs/gitobj/errors"
+	"github.com/git-lfs/gitobj/v2/errors"
 	"github.com/stretchr/testify/assert"
 )
 

object.go

@@ -1,6 +1,9 @@
 package gitobj
 
-import "io"
+import (
+	"hash"
+	"io"
+)
 
 // Object is an interface satisfied by any concrete type that represents a loose
 // Git object.
@@ -29,7 +32,7 @@ type Object interface {
 	//
 	// If an(y) error was encountered, it should be returned immediately,
 	// along with the number of bytes read up to that point.
-	Decode(from io.Reader, size int64) (n int, err error)
+	Decode(hash hash.Hash, from io.Reader, size int64) (n int, err error)
 
 	// Type returns the ObjectType constant that represents an instance of
 	// the implementing type.