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-rw-r--r--packfile/delta.go93
-rw-r--r--packfile/doc.go168
-rw-r--r--packfile/objects.go222
-rw-r--r--packfile/objects_test.go55
-rw-r--r--packfile/packfile.go82
-rw-r--r--packfile/reader.go412
-rw-r--r--packfile/reader_test.go35
7 files changed, 1067 insertions, 0 deletions
diff --git a/packfile/delta.go b/packfile/delta.go
new file mode 100644
index 0000000..86b556f
--- /dev/null
+++ b/packfile/delta.go
@@ -0,0 +1,93 @@
+package packfile
+
+const delta_size_min = 4
+
+func deltaHeaderSize(b []byte) (uint, []byte) {
+ var size, j uint
+ var cmd byte
+ for {
+ cmd = b[j]
+ size |= (uint(cmd) & 0x7f) << (j * 7)
+ j++
+ if uint(cmd)&0xb80 == 0 || j == uint(len(b)) {
+ break
+ }
+ }
+ return size, b[j:]
+}
+
+func PatchDelta(src, delta []byte) []byte {
+ if len(delta) < delta_size_min {
+ return nil
+ }
+ size, delta := deltaHeaderSize(delta)
+ if size != uint(len(src)) {
+ return nil
+ }
+ size, delta = deltaHeaderSize(delta)
+ origSize := size
+
+ dest := make([]byte, 0)
+
+ // var offset uint
+ var cmd byte
+ for {
+ cmd = delta[0]
+ delta = delta[1:]
+ if (cmd & 0x80) != 0 {
+ var cp_off, cp_size uint
+ if (cmd & 0x01) != 0 {
+ cp_off = uint(delta[0])
+ delta = delta[1:]
+ }
+ if (cmd & 0x02) != 0 {
+ cp_off |= uint(delta[0]) << 8
+ delta = delta[1:]
+ }
+ if (cmd & 0x04) != 0 {
+ cp_off |= uint(delta[0]) << 16
+ delta = delta[1:]
+ }
+ if (cmd & 0x08) != 0 {
+ cp_off |= uint(delta[0]) << 24
+ delta = delta[1:]
+ }
+
+ if (cmd & 0x10) != 0 {
+ cp_size = uint(delta[0])
+ delta = delta[1:]
+ }
+ if (cmd & 0x20) != 0 {
+ cp_size |= uint(delta[0]) << 8
+ delta = delta[1:]
+ }
+ if (cmd & 0x40) != 0 {
+ cp_size |= uint(delta[0]) << 16
+ delta = delta[1:]
+ }
+ if cp_size == 0 {
+ cp_size = 0x10000
+ }
+ if cp_off+cp_size < cp_off ||
+ cp_off+cp_size > uint(len(src)) ||
+ cp_size > origSize {
+ break
+ }
+ dest = append(dest, src[cp_off:cp_off+cp_size]...)
+ size -= cp_size
+ } else if cmd != 0 {
+ if uint(cmd) > origSize {
+ break
+ }
+ dest = append(dest, delta[0:uint(cmd)]...)
+ size -= uint(cmd)
+ delta = delta[uint(cmd):]
+ } else {
+ return nil
+ }
+ if size <= 0 {
+ break
+ }
+ }
+ return dest
+}
diff --git a/packfile/doc.go b/packfile/doc.go
new file mode 100644
index 0000000..1fc28da
--- /dev/null
+++ b/packfile/doc.go
@@ -0,0 +1,168 @@
+package packfile
+
+// Code from:
+// https://github.com/gitchain/gitchain/tree/master/git @ 4c2fabdf9
+//
+// GIT pack format
+// ===============
+//
+// == pack-*.pack files have the following format:
+//
+// - A header appears at the beginning and consists of the following:
+//
+// 4-byte signature:
+// The signature is: {'P', 'A', 'C', 'K'}
+//
+// 4-byte version number (network byte order):
+// GIT currently accepts version number 2 or 3 but
+// generates version 2 only.
+//
+// 4-byte number of objects contained in the pack (network byte order)
+//
+// Observation: we cannot have more than 4G versions ;-) and
+// more than 4G objects in a pack.
+//
+// - The header is followed by number of object entries, each of
+// which looks like this:
+//
+// (undeltified representation)
+// n-byte type and length (3-bit type, (n-1)*7+4-bit length)
+// compressed data
+//
+// (deltified representation)
+// n-byte type and length (3-bit type, (n-1)*7+4-bit length)
+// 20-byte base object name
+// compressed delta data
+//
+// Observation: length of each object is encoded in a variable
+// length format and is not constrained to 32-bit or anything.
+//
+// - The trailer records 20-byte SHA1 checksum of all of the above.
+//
+// == Original (version 1) pack-*.idx files have the following format:
+//
+// - The header consists of 256 4-byte network byte order
+// integers. N-th entry of this table records the number of
+// objects in the corresponding pack, the first byte of whose
+// object name is less than or equal to N. This is called the
+// 'first-level fan-out' table.
+//
+// - The header is followed by sorted 24-byte entries, one entry
+// per object in the pack. Each entry is:
+//
+// 4-byte network byte order integer, recording where the
+// object is stored in the packfile as the offset from the
+// beginning.
+//
+// 20-byte object name.
+//
+// - The file is concluded with a trailer:
+//
+// A copy of the 20-byte SHA1 checksum at the end of
+// corresponding packfile.
+//
+// 20-byte SHA1-checksum of all of the above.
+//
+// Pack Idx file:
+//
+// -- +--------------------------------+
+// fanout | fanout[0] = 2 (for example) |-.
+// table +--------------------------------+ |
+// | fanout[1] | |
+// +--------------------------------+ |
+// | fanout[2] | |
+// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
+// | fanout[255] = total objects |---.
+// -- +--------------------------------+ | |
+// main | offset | | |
+// index | object name 00XXXXXXXXXXXXXXXX | | |
+// table +--------------------------------+ | |
+// | offset | | |
+// | object name 00XXXXXXXXXXXXXXXX | | |
+// +--------------------------------+<+ |
+// .-| offset | |
+// | | object name 01XXXXXXXXXXXXXXXX | |
+// | +--------------------------------+ |
+// | | offset | |
+// | | object name 01XXXXXXXXXXXXXXXX | |
+// | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
+// | | offset | |
+// | | object name FFXXXXXXXXXXXXXXXX | |
+// --| +--------------------------------+<--+
+// trailer | | packfile checksum |
+// | +--------------------------------+
+// | | idxfile checksum |
+// | +--------------------------------+
+// .-------.
+// |
+// Pack file entry: <+
+//
+// packed object header:
+// 1-byte size extension bit (MSB)
+// type (next 3 bit)
+// size0 (lower 4-bit)
+// n-byte sizeN (as long as MSB is set, each 7-bit)
+// size0..sizeN form 4+7+7+..+7 bit integer, size0
+// is the least significant part, and sizeN is the
+// most significant part.
+// packed object data:
+// If it is not DELTA, then deflated bytes (the size above
+// is the size before compression).
+// If it is REF_DELTA, then
+// 20-byte base object name SHA1 (the size above is the
+// size of the delta data that follows).
+// delta data, deflated.
+// If it is OFS_DELTA, then
+// n-byte offset (see below) interpreted as a negative
+// offset from the type-byte of the header of the
+// ofs-delta entry (the size above is the size of
+// the delta data that follows).
+// delta data, deflated.
+//
+// offset encoding:
+// n bytes with MSB set in all but the last one.
+// The offset is then the number constructed by
+// concatenating the lower 7 bit of each byte, and
+// for n >= 2 adding 2^7 + 2^14 + ... + 2^(7*(n-1))
+// to the result.
+//
+//
+//
+// == Version 2 pack-*.idx files support packs larger than 4 GiB, and
+// have some other reorganizations. They have the format:
+//
+// - A 4-byte magic number '\377tOc' which is an unreasonable
+// fanout[0] value.
+//
+// - A 4-byte version number (= 2)
+//
+// - A 256-entry fan-out table just like v1.
+//
+// - A table of sorted 20-byte SHA1 object names. These are
+// packed together without offset values to reduce the cache
+// footprint of the binary search for a specific object name.
+//
+// - A table of 4-byte CRC32 values of the packed object data.
+// This is new in v2 so compressed data can be copied directly
+// from pack to pack during repacking without undetected
+// data corruption.
+//
+// - A table of 4-byte offset values (in network byte order).
+// These are usually 31-bit pack file offsets, but large
+// offsets are encoded as an index into the next table with
+// the msbit set.
+//
+// - A table of 8-byte offset entries (empty for pack files less
+// than 2 GiB). Pack files are organized with heavily used
+// objects toward the front, so most object references should
+// not need to refer to this table.
+//
+// - The same trailer as a v1 pack file:
+//
+// A copy of the 20-byte SHA1 checksum at the end of
+// corresponding packfile.
+//
+// 20-byte SHA1-checksum of all of the above.
+//
+// From:
+// https://www.kernel.org/pub/software/scm/git/docs/v1.7.5/technical/pack-protocol.txt
diff --git a/packfile/objects.go b/packfile/objects.go
new file mode 100644
index 0000000..3c77a33
--- /dev/null
+++ b/packfile/objects.go
@@ -0,0 +1,222 @@
+package packfile
+
+import (
+ "bytes"
+ "compress/zlib"
+ "crypto/sha1"
+ "encoding/hex"
+ "fmt"
+ "io/ioutil"
+ "strconv"
+ "time"
+)
+
+type Object interface {
+ Type() string
+ Hash() string
+}
+
+type Hash []byte
+
+func (h Hash) String() string {
+ return hex.EncodeToString(h)
+}
+
+type Commit struct {
+ Tree Hash
+ Parents []Hash
+ Author Signature
+ Committer Signature
+ Message string
+ hash string
+}
+
+func NewCommit(b []byte) (*Commit, error) {
+ o := &Commit{hash: calculateHash("commit", b)}
+
+ lines := bytes.Split(b, []byte{'\n'})
+ for i := range lines {
+ if len(lines[i]) > 0 {
+ var err error
+
+ split := bytes.SplitN(lines[i], []byte{' '}, 2)
+ switch string(split[0]) {
+ case "tree":
+ o.Tree = make([]byte, 20)
+ _, err = hex.Decode(o.Tree, split[1])
+ case "parent":
+ h := make([]byte, 20)
+ _, err = hex.Decode(h, split[1])
+ if err == nil {
+ o.Parents = append(o.Parents, h)
+ }
+ case "author":
+ o.Author = NewSignature(split[1])
+ case "committer":
+ o.Committer = NewSignature(split[1])
+ }
+
+ if err != nil {
+ return nil, err
+ }
+ } else {
+ o.Message = string(bytes.Join(append(lines[i+1:]), []byte{'\n'}))
+ break
+ }
+ }
+
+ return o, nil
+}
+
+func (o *Commit) Type() string {
+ return "commit"
+}
+
+func (o *Commit) Hash() string {
+ return o.hash
+}
+
+type Signature struct {
+ Name string
+ Email string
+ When time.Time
+}
+
+func NewSignature(signature []byte) Signature {
+ ret := Signature{}
+ if len(signature) == 0 {
+ return ret
+ }
+
+ from := 0
+ state := 'n' // n: name, e: email, t: timestamp, z: timezone
+ for i := 0; ; i++ {
+ var c byte
+ var end bool
+ if i < len(signature) {
+ c = signature[i]
+ } else {
+ end = true
+ }
+
+ switch state {
+ case 'n':
+ if c == '<' || end {
+ if i == 0 {
+ break
+ }
+ ret.Name = string(signature[from : i-1])
+ state = 'e'
+ from = i + 1
+ }
+ case 'e':
+ if c == '>' || end {
+ ret.Email = string(signature[from:i])
+ i++
+ state = 't'
+ from = i + 1
+ }
+ case 't':
+ if c == ' ' || end {
+ t, err := strconv.ParseInt(string(signature[from:i]), 10, 64)
+ if err == nil {
+ ret.When = time.Unix(t, 0)
+ }
+ end = true
+ }
+ }
+
+ if end {
+ break
+ }
+ }
+
+ return ret
+}
+
+func (s *Signature) String() string {
+ return fmt.Sprintf("%q <%s> @ %s", s.Name, s.Email, s.When)
+}
+
+type Tree struct {
+ Entries []TreeEntry
+ hash string
+}
+
+type TreeEntry struct {
+ Name string
+ Hash string
+}
+
+func NewTree(b []byte) (*Tree, error) {
+ o := &Tree{hash: calculateHash("tree", b)}
+
+ if len(b) == 0 {
+ return o, nil
+ }
+
+ zr, e := zlib.NewReader(bytes.NewBuffer(b))
+ if e == nil {
+ defer zr.Close()
+ var err error
+ b, err = ioutil.ReadAll(zr)
+ if err != nil {
+ return nil, err
+ }
+ }
+
+ body := b
+ for {
+ split := bytes.SplitN(body, []byte{0}, 2)
+ split1 := bytes.SplitN(split[0], []byte{' '}, 2)
+
+ o.Entries = append(o.Entries, TreeEntry{
+ Name: string(split1[1]),
+ Hash: fmt.Sprintf("%x", split[1][0:20]),
+ })
+
+ body = split[1][20:]
+ if len(split[1]) == 20 {
+ break
+ }
+ }
+
+ return o, nil
+}
+
+func (o *Tree) Type() string {
+ return "tree"
+}
+
+func (o *Tree) Hash() string {
+ return o.hash
+}
+
+type Blob struct {
+ Len int
+ hash string
+}
+
+func NewBlob(b []byte) (*Blob, error) {
+ return &Blob{Len: len(b), hash: calculateHash("blob", b)}, nil
+}
+
+func (o *Blob) Type() string {
+ return "blob"
+}
+
+func (o *Blob) Hash() string {
+ return o.hash
+}
+
+func calculateHash(objType string, content []byte) string {
+ header := []byte(objType)
+ header = append(header, ' ')
+ header = strconv.AppendInt(header, int64(len(content)), 10)
+ header = append(header, 0)
+ header = append(header, content...)
+
+ return fmt.Sprintf("%x", sha1.Sum(header))
+}
+
+type ContentCallback func(hash string, content []byte)
diff --git a/packfile/objects_test.go b/packfile/objects_test.go
new file mode 100644
index 0000000..07609e3
--- /dev/null
+++ b/packfile/objects_test.go
@@ -0,0 +1,55 @@
+package packfile
+
+import (
+ "testing"
+ "time"
+
+ "github.com/stretchr/testify/assert"
+)
+
+func TestCalculateHash(t *testing.T) {
+ assert.Equal(t, "e69de29bb2d1d6434b8b29ae775ad8c2e48c5391", calculateHash("blob", []byte("")))
+ assert.Equal(t, "8ab686eafeb1f44702738c8b0f24f2567c36da6d", calculateHash("blob", []byte("Hello, World!\n")))
+}
+
+func TestSignature(t *testing.T) {
+ cases := map[string]Signature{
+ `Foo Bar <foo@bar.com> 1257894000 +0100`: {
+ Name: "Foo Bar",
+ Email: "foo@bar.com",
+ When: time.Unix(1257894000, 0),
+ },
+ `Foo Bar <> 1257894000 +0100`: {
+ Name: "Foo Bar",
+ Email: "",
+ When: time.Unix(1257894000, 0),
+ },
+ ` <> 1257894000`: {
+ Name: "",
+ Email: "",
+ When: time.Unix(1257894000, 0),
+ },
+ `Foo Bar <foo@bar.com>`: {
+ Name: "Foo Bar",
+ Email: "foo@bar.com",
+ When: time.Time{},
+ },
+ ``: {
+ Name: "",
+ Email: "",
+ When: time.Time{},
+ },
+ `<`: {
+ Name: "",
+ Email: "",
+ When: time.Time{},
+ },
+ }
+
+ for raw, exp := range cases {
+ got := NewSignature([]byte(raw))
+ assert.Equal(t, exp.Name, got.Name)
+ assert.Equal(t, exp.Email, got.Email)
+ assert.Equal(t, exp.When.Unix(), got.When.Unix())
+ }
+}
diff --git a/packfile/packfile.go b/packfile/packfile.go
new file mode 100644
index 0000000..e670cd0
--- /dev/null
+++ b/packfile/packfile.go
@@ -0,0 +1,82 @@
+package packfile
+
+import "fmt"
+
+type Packfile struct {
+ Version uint32
+ ObjectCount int
+ Checksum []byte
+ Commits map[string]*Commit
+ Trees map[string]*Tree
+ Blobs map[string]*Blob
+}
+
+func NewPackfile() *Packfile {
+ return &Packfile{
+ Commits: make(map[string]*Commit, 0),
+ Trees: make(map[string]*Tree, 0),
+ Blobs: make(map[string]*Blob, 0),
+ }
+}
+
+type BlobEntry struct {
+ path string
+ *Blob
+}
+
+type SubtreeEntry struct {
+ path string
+ *Tree
+ TreeCh
+}
+
+type treeEntry interface {
+ isTreeEntry()
+ Path() string
+}
+
+func (b BlobEntry) isTreeEntry() {}
+func (b BlobEntry) Path() string { return b.path }
+func (b SubtreeEntry) isTreeEntry() {}
+func (b SubtreeEntry) Path() string { return b.path }
+
+type TreeCh <-chan treeEntry
+
+func (p *Packfile) WalkCommit(commitHash string) (TreeCh, error) {
+ commit, ok := p.Commits[commitHash]
+ if !ok {
+ return nil, fmt.Errorf("Unable to find %q commit", commitHash)
+ }
+
+ treeHash := fmt.Sprintf("%x", string(commit.Tree))
+ return p.WalkTree(p.Trees[treeHash]), nil
+}
+
+func (p *Packfile) WalkTree(tree *Tree) TreeCh {
+ return p.walkTree(tree, "")
+}
+
+func (p *Packfile) walkTree(tree *Tree, pathPrefix string) TreeCh {
+ ch := make(chan treeEntry)
+
+ if tree == nil {
+ close(ch)
+ return ch
+ }
+
+ go func() {
+ defer func() {
+ close(ch)
+ }()
+ for _, e := range tree.Entries {
+ path := pathPrefix + e.Name
+ if blob, ok := p.Blobs[e.Hash]; ok {
+ ch <- BlobEntry{path, blob}
+ } else if subtree, ok := p.Trees[e.Hash]; ok {
+ ch <- SubtreeEntry{path, subtree, p.walkTree(subtree, path+"/")}
+ }
+ }
+ }()
+
+ return ch
+}
diff --git a/packfile/reader.go b/packfile/reader.go
new file mode 100644
index 0000000..3725822
--- /dev/null
+++ b/packfile/reader.go
@@ -0,0 +1,412 @@
+package packfile
+
+import (
+ "bytes"
+ "compress/zlib"
+ "encoding/binary"
+ "errors"
+ "fmt"
+ "io"
+ "io/ioutil"
+)
+
+const MaxObjectsLimit = 1000000
+
+type PackfileReader struct {
+ r io.Reader
+
+ objects map[string]packfileObject
+ offsets map[int]string
+ deltas []packfileDelta
+
+ // The give back logic is explained in the giveBack method.
+ startedGivingBack bool
+ givebackBuffer []byte
+ givenBack io.Reader
+ contentCallback ContentCallback
+}
+
+// Sometimes, after reading an object from a packfile, there will be
+// a few bytes with garbage data before the next object comes by.
+// There is no way of reliably noticing this until when trying to read the
+// next object and failing because zlib parses an invalid header. We can't
+// notice before, because parsing the object's header (size, type, etc.)
+// doesn't fail.
+//
+// At that point, we want to give back to the reader the bytes we've read
+// since the last object, shift the input by one byte, and try again. That's
+// why we save the bytes we read on each object and, if it fails in the middle
+// of parsing it, those bytes will be read the next times you call Read() on
+// a objectReader derived from a PackfileReader.readObject, until they run out.
+func (pr *PackfileReader) giveBack() {
+ pr.givenBack = bytes.NewReader(pr.givebackBuffer)
+ pr.givebackBuffer = nil
+}
+
+type packfileObject struct {
+ bytes []byte
+ typ int8
+}
+
+type packfileDelta struct {
+ hash string
+ delta []byte
+}
+
+func NewPackfileReader(r io.Reader, contentCallback ContentCallback) (*PackfileReader, error) {
+ return &PackfileReader{
+ r: r,
+ objects: map[string]packfileObject{},
+ offsets: map[int]string{},
+ contentCallback: contentCallback,
+ }, nil
+}
+
+func (p *PackfileReader) Read() (*Packfile, error) {
+ packfile := NewPackfile()
+
+ if err := p.validateSignature(); err != nil {
+ if err == io.EOF {
+ // This is an empty repo. It's OK.
+ return packfile, nil
+ }
+ return nil, err
+ }
+
+ var err error
+ ver, err := p.readInt32()
+ if err != nil {
+ return nil, err
+ }
+
+ count, err := p.readInt32()
+ if err != nil {
+ return nil, err
+ }
+
+ packfile.Version = uint32(ver)
+ packfile.ObjectCount = int(count)
+
+ if packfile.ObjectCount > MaxObjectsLimit {
+ return nil, NewError("too many objects (%d)", packfile.ObjectCount)
+ }
+
+ if err := p.readObjects(packfile); err != nil {
+ return nil, err
+ }
+
+ return packfile, nil
+}
+
+func (p *PackfileReader) validateSignature() error {
+ var signature = make([]byte, 4)
+ if _, err := p.r.Read(signature); err != nil {
+ return err
+ }
+
+ if !bytes.Equal(signature, []byte{'P', 'A', 'C', 'K'}) {
+ return NewError("Pack file does not start with 'PACK'")
+ }
+
+ return nil
+}
+
+func (p *PackfileReader) readInt32() (uint32, error) {
+ var value uint32
+ if err := binary.Read(p.r, binary.BigEndian, &value); err != nil {
+ fmt.Println(err)
+
+ return 0, err
+ }
+
+ return value, nil
+}
+
+func (p *PackfileReader) readObjects(packfile *Packfile) error {
+ p.startedGivingBack = true
+
+ offset := 12
+ for i := 0; i < packfile.ObjectCount; i++ {
+ r, err := p.readObject(packfile, offset)
+ if err != nil && err != io.EOF {
+ return err
+ }
+
+ p.offsets[offset] = r.hash
+ offset += r.counter + 4
+
+ unknownForBytes := make([]byte, 4)
+ p.r.Read(unknownForBytes)
+
+ if err == io.EOF {
+ break
+ }
+ }
+
+ return nil
+}
+
+const (
+ OBJ_COMMIT = 1
+ OBJ_TREE = 2
+ OBJ_BLOB = 3
+ OBJ_TAG = 4
+ OBJ_OFS_DELTA = 6
+ OBJ_REF_DELTA = 7
+)
+
+const SIZE_LIMIT uint64 = 1 << 32 //4GB
+
+type objectReader struct {
+ pr *PackfileReader
+ pf *Packfile
+ offset int
+ hash string
+
+ typ int8
+ size uint64
+ counter int
+}
+
+func (p *PackfileReader) readObject(packfile *Packfile, offset int) (*objectReader, error) {
+ o, err := newObjectReader(p, packfile, offset)
+ if err != nil {
+ return nil, err
+ }
+
+ switch o.typ {
+ case OBJ_REF_DELTA:
+ err = o.readREFDelta()
+ case OBJ_OFS_DELTA:
+ err = o.readOFSDelta()
+ case OBJ_COMMIT, OBJ_TREE, OBJ_BLOB, OBJ_TAG:
+ err = o.readObject()
+ default:
+ err = NewError("Invalid git object tag %q", o.typ)
+ }
+ if err == ErrZlibHeader {
+ p.giveBack()
+ io.CopyN(ioutil.Discard, p.r, 1)
+ return p.readObject(packfile, offset)
+ }
+
+ return o, err
+}
+
+func newObjectReader(pr *PackfileReader, pf *Packfile, offset int) (*objectReader, error) {
+ o := &objectReader{pr: pr, pf: pf, offset: offset}
+ buf := make([]byte, 1)
+ if _, err := o.Read(buf); err != nil {
+ return nil, err
+ }
+
+ o.typ = int8((buf[0] >> 4) & 7)
+ o.size = uint64(buf[0] & 15)
+
+ var shift uint = 4
+ for buf[0]&0x80 == 0x80 {
+ if _, err := o.Read(buf); err != nil {
+ return nil, err
+ }
+
+ o.size += uint64(buf[0]&0x7f) << shift
+ shift += 7
+ }
+
+ return o, nil
+}
+
+func (o *objectReader) readREFDelta() error {
+ ref := make([]byte, 20)
+ o.Read(ref)
+
+ buf, err := o.inflate()
+ if err != nil {
+ return err
+ }
+
+ refhash := fmt.Sprintf("%x", ref)
+ referenced, ok := o.pr.objects[refhash]
+ if !ok {
+ o.pr.deltas = append(o.pr.deltas, packfileDelta{hash: refhash, delta: buf})
+ } else {
+ patched := PatchDelta(referenced.bytes, buf)
+ if patched == nil {
+ return NewError("error while patching %x", ref)
+ }
+ o.typ = referenced.typ
+ err = o.addObject(patched)
+ if err != nil {
+ return err
+ }
+ }
+
+ return nil
+}
+
+func (o *objectReader) readOFSDelta() error {
+ // read negative offset
+ var b uint8
+ binary.Read(o, binary.BigEndian, &b)
+ var noffset int = int(b & 0x7f)
+ for (b & 0x80) != 0 {
+ noffset += 1
+ binary.Read(o, binary.BigEndian, &b)
+ noffset = (noffset << 7) + int(b&0x7f)
+ }
+
+ buf, err := o.inflate()
+ if err != nil {
+ return err
+ }
+
+ refhash := o.pr.offsets[o.offset-noffset]
+ referenced, ok := o.pr.objects[refhash]
+ if !ok {
+ return NewError("can't find a pack entry at %d", o.offset-noffset)
+ } else {
+ patched := PatchDelta(referenced.bytes, buf)
+ if patched == nil {
+ return NewError("error while patching %x", refhash)
+ }
+ o.typ = referenced.typ
+ err = o.addObject(patched)
+ if err != nil {
+ return err
+ }
+ }
+
+ return nil
+}
+
+func (o *objectReader) readObject() error {
+ buf, err := o.inflate()
+ if err != nil {
+ return err
+ }
+
+ return o.addObject(buf)
+}
+
+func (o *objectReader) addObject(bytes []byte) error {
+ var hash string
+
+ switch o.typ {
+ case OBJ_COMMIT:
+ c, err := NewCommit(bytes)
+ if err != nil {
+ return err
+ }
+ o.pf.Commits[c.Hash()] = c
+ hash = c.Hash()
+ case OBJ_TREE:
+ c, err := NewTree(bytes)
+ if err != nil {
+ return err
+ }
+ o.pf.Trees[c.Hash()] = c
+ hash = c.Hash()
+ case OBJ_BLOB:
+ c, err := NewBlob(bytes)
+ if err != nil {
+ return err
+ }
+ o.pf.Blobs[c.Hash()] = c
+ hash = c.Hash()
+
+ if o.pr.contentCallback != nil {
+ o.pr.contentCallback(hash, bytes)
+ }
+ }
+
+ o.pr.objects[hash] = packfileObject{bytes: bytes, typ: o.typ}
+ o.hash = hash
+
+ return nil
+
+}
+
+func (o *objectReader) inflate() ([]byte, error) {
+ //Quick fix "Invalid git object tag '\x00'" when the length of a object is 0
+ if o.size == 0 {
+ buf := make([]byte, 4)
+ if _, err := o.Read(buf); err != nil {
+ return nil, err
+ }
+
+ return nil, nil
+ }
+
+ zr, err := zlib.NewReader(o)
+ if err != nil {
+ if err.Error() == "zlib: invalid header" {
+ return nil, ErrZlibHeader
+ } else {
+ return nil, NewError("error opening packfile's object zlib: %v", err)
+ }
+ }
+
+ defer zr.Close()
+
+ if o.size > SIZE_LIMIT {
+ return nil, NewError("the object size exceeed the allowed limit: %d", o.size)
+ }
+
+ buf := make([]byte, o.size)
+ read := 0
+ for read < int(o.size) {
+ n, err := zr.Read(buf[read:])
+ if err != nil {
+ return nil, err
+ }
+
+ read += n
+ }
+
+ if read != int(o.size) {
+ return nil, NewError("inflated size mismatch, expected %d, got %d", o.size, read)
+ }
+
+ return buf, nil
+}
+
+func (o *objectReader) Read(p []byte) (int, error) {
+ i := 0
+ if o.pr.givenBack != nil {
+ i1, err := o.pr.givenBack.Read(p)
+ if err == nil {
+ i += i1
+ } else {
+ o.pr.givenBack = nil
+ }
+ }
+
+ i2, err := o.pr.r.Read(p[i:])
+ i += i2
+ o.counter += i
+ if err == nil && o.pr.startedGivingBack {
+ o.pr.givebackBuffer = append(o.pr.givebackBuffer, p[:i]...)
+ }
+ return i, err
+}
+
+func (o *objectReader) ReadByte() (byte, error) {
+ var c byte
+ if err := binary.Read(o, binary.BigEndian, &c); err != nil {
+ return 0, err
+ }
+
+ return c, nil
+}
+
+type ReaderError struct {
+ Msg string // description of error
+}
+
+func NewError(format string, args ...interface{}) error {
+ return &ReaderError{Msg: fmt.Sprintf(format, args...)}
+}
+
+func (e *ReaderError) Error() string { return e.Msg }
+
+var ErrZlibHeader = errors.New("zlib: invalid header")
diff --git a/packfile/reader_test.go b/packfile/reader_test.go
new file mode 100644
index 0000000..e52cbc3
--- /dev/null
+++ b/packfile/reader_test.go
@@ -0,0 +1,35 @@
+package packfile
+
+import (
+ "bytes"
+ "encoding/base64"
+ "testing"
+
+ "github.com/stretchr/testify/assert"
+)
+
+var packFileWithEmptyObjects = "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"
+
+func TestReadPackfile(t *testing.T) {
+ data, _ := base64.StdEncoding.DecodeString(packFileWithEmptyObjects)
+ d := bytes.NewReader(data)
+
+ r, err := NewPackfileReader(d, nil)
+ assert.Nil(t, err)
+
+ p, err := r.Read()
+ assert.Nil(t, err)
+
+ assert.Equal(t, 11, p.ObjectCount)
+ assert.Equal(t, 4, len(p.Commits))
+ assert.Equal(t, 4, len(p.Trees))
+}
+
+func TestReadPackfileInvalid(t *testing.T) {
+ r, err := NewPackfileReader(bytes.NewReader([]byte("dasdsadasas")), nil)
+ assert.Nil(t, err)
+
+ _, err = r.Read()
+ _, ok := err.(*ReaderError)
+ assert.True(t, ok)
+}
generated by cgit (git 2.34.1) at 2024-11-14 13:28:22 +0000