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pack: Hide more implementation details

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This commit is contained in:
Michael Eischer 2022-03-28 22:12:16 +02:00
parent a773cb6527
commit fefe9f5c0e
3 changed files with 27 additions and 27 deletions
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24
internal/pack/pack.go
View file

@ -47,7 +47,7 @@ func (p *Packer) Add(t restic.BlobType, id restic.ID, data []byte) (int, error)
return n, errors.Wrap(err, "Write")
}
var EntrySize = uint(binary.Size(restic.BlobType(0)) + headerLengthSize + len(restic.ID{}))
var entrySize = uint(binary.Size(restic.BlobType(0)) + headerLengthSize + len(restic.ID{}))
// headerEntry describes the format of header entries. It serves only as
// documentation.
@ -101,7 +101,7 @@ func (p *Packer) Finalize() (uint, error) {
// makeHeader constructs the header for p.
func (p *Packer) makeHeader() ([]byte, error) {
buf := make([]byte, 0, len(p.blobs)*int(EntrySize))
buf := make([]byte, 0, len(p.blobs)*int(entrySize))
for _, b := range p.blobs {
switch b.Type {
@ -152,7 +152,7 @@ func (p *Packer) String() string {
var (
// we require at least one entry in the header, and one blob for a pack file
minFileSize = EntrySize + crypto.Extension + uint(headerLengthSize)
minFileSize = entrySize + crypto.Extension + uint(headerLengthSize)
)
const (
@ -173,7 +173,7 @@ const (
// the appropriate size.
func readRecords(rd io.ReaderAt, size int64, max int) ([]byte, int, error) {
var bufsize int
bufsize += max * int(EntrySize)
bufsize += max * int(entrySize)
bufsize += crypto.Extension
bufsize += headerLengthSize
@ -197,7 +197,7 @@ func readRecords(rd io.ReaderAt, size int64, max int) ([]byte, int, error) {
err = InvalidFileError{Message: "header length is zero"}
case hlen < crypto.Extension:
err = InvalidFileError{Message: "header length is too small"}
case (hlen-crypto.Extension)%uint32(EntrySize) != 0:
case (hlen-crypto.Extension)%uint32(entrySize) != 0:
err = InvalidFileError{Message: "header length is invalid"}
case int64(hlen) > size-int64(headerLengthSize):
err = InvalidFileError{Message: "header is larger than file"}
@ -208,7 +208,7 @@ func readRecords(rd io.ReaderAt, size int64, max int) ([]byte, int, error) {
return nil, 0, errors.Wrap(err, "readHeader")
}
total := (int(hlen) - crypto.Extension) / int(EntrySize)
total := (int(hlen) - crypto.Extension) / int(entrySize)
if total < max {
// truncate to the beginning of the pack header
b = b[len(b)-int(hlen):]
@ -274,7 +274,7 @@ func List(k *crypto.Key, rd io.ReaderAt, size int64) (entries []restic.Blob, hdr
return nil, 0, err
}
entries = make([]restic.Blob, 0, uint(len(buf))/EntrySize)
entries = make([]restic.Blob, 0, uint(len(buf))/entrySize)
pos := uint(0)
for len(buf) > 0 {
@ -286,18 +286,18 @@ func List(k *crypto.Key, rd io.ReaderAt, size int64) (entries []restic.Blob, hdr
entries = append(entries, entry)
pos += entry.Length
buf = buf[EntrySize:]
buf = buf[entrySize:]
}
return entries, hdrSize, nil
}
func parseHeaderEntry(p []byte) (b restic.Blob, err error) {
if uint(len(p)) < EntrySize {
if uint(len(p)) < entrySize {
err = errors.Errorf("parseHeaderEntry: buffer of size %d too short", len(p))
return b, err
}
p = p[:EntrySize]
p = p[:entrySize]
switch p[0] {
case 0:
@ -315,7 +315,7 @@ func parseHeaderEntry(p []byte) (b restic.Blob, err error) {
}
func CalculateHeaderSize(blobs []restic.Blob) int {
return headerSize + len(blobs)*int(EntrySize)
return headerSize + len(blobs)*int(entrySize)
}
// Size returns the size of all packs computed by index information.
@ -333,7 +333,7 @@ func Size(ctx context.Context, mi restic.MasterIndex, onlyHdr bool) map[restic.I
if !onlyHdr {
size += int64(blob.Length)
}
packSize[blob.PackID] = size + int64(EntrySize)
packSize[blob.PackID] = size + int64(entrySize)
}
return packSize

16
internal/pack/pack_internal_test.go
View file

@ -41,7 +41,7 @@ func TestParseHeaderEntry(t *testing.T) {
buf.Reset()
_ = binary.Write(buf, binary.LittleEndian, &h)
b, err = parseHeaderEntry(buf.Bytes()[:EntrySize-1])
b, err = parseHeaderEntry(buf.Bytes()[:entrySize-1])
rtest.Assert(t, err != nil, "no error for short input")
}
@ -58,7 +58,7 @@ func (rd *countingReaderAt) ReadAt(p []byte, off int64) (n int, err error) {
func TestReadHeaderEagerLoad(t *testing.T) {
testReadHeader := func(dataSize, entryCount, expectedReadInvocationCount int) {
expectedHeader := rtest.Random(0, entryCount*int(EntrySize)+crypto.Extension)
expectedHeader := rtest.Random(0, entryCount*int(entrySize)+crypto.Extension)
buf := &bytes.Buffer{}
buf.Write(rtest.Random(0, dataSize)) // pack blobs data
@ -83,8 +83,8 @@ func TestReadHeaderEagerLoad(t *testing.T) {
testReadHeader(100, eagerEntries+1, 2)
// file size == eager header load size
eagerLoadSize := int((eagerEntries * EntrySize) + crypto.Extension)
headerSize := int(1*EntrySize) + crypto.Extension
eagerLoadSize := int((eagerEntries * entrySize) + crypto.Extension)
headerSize := int(1*entrySize) + crypto.Extension
dataSize := eagerLoadSize - headerSize - binary.Size(uint32(0))
testReadHeader(dataSize-1, 1, 1)
testReadHeader(dataSize, 1, 1)
@ -96,8 +96,8 @@ func TestReadHeaderEagerLoad(t *testing.T) {
func TestReadRecords(t *testing.T) {
testReadRecords := func(dataSize, entryCount, totalRecords int) {
totalHeader := rtest.Random(0, totalRecords*int(EntrySize)+crypto.Extension)
off := len(totalHeader) - (entryCount*int(EntrySize) + crypto.Extension)
totalHeader := rtest.Random(0, totalRecords*int(entrySize)+crypto.Extension)
off := len(totalHeader) - (entryCount*int(entrySize) + crypto.Extension)
if off < 0 {
off = 0
}
@ -127,8 +127,8 @@ func TestReadRecords(t *testing.T) {
testReadRecords(100, eagerEntries, eagerEntries+1)
// file size == eager header load size
eagerLoadSize := int((eagerEntries * EntrySize) + crypto.Extension)
headerSize := int(1*EntrySize) + crypto.Extension
eagerLoadSize := int((eagerEntries * entrySize) + crypto.Extension)
headerSize := int(1*entrySize) + crypto.Extension
dataSize := eagerLoadSize - headerSize - binary.Size(uint32(0))
testReadRecords(dataSize-1, 1, 1)
testReadRecords(dataSize, 1, 1)

14
internal/pack/pack_test.go
View file

@ -5,7 +5,6 @@ import (
"context"
"crypto/rand"
"crypto/sha256"
"encoding/binary"
"encoding/json"
"io"
"testing"
@ -54,17 +53,18 @@ func verifyBlobs(t testing.TB, bufs []Buf, k *crypto.Key, rd io.ReaderAt, packSi
for _, buf := range bufs {
written += len(buf.data)
}
// header length + header + header crypto
headerSize := binary.Size(uint32(0)) + restic.CiphertextLength(len(bufs)*int(pack.EntrySize))
written += headerSize
// check length
rtest.Equals(t, uint(written), packSize)
// read and parse it again
entries, hdrSize, err := pack.List(k, rd, int64(packSize))
rtest.OK(t, err)
rtest.Equals(t, len(entries), len(bufs))
// check the head size calculation for consistency
headerSize := pack.CalculateHeaderSize(entries)
written += headerSize
// check length
rtest.Equals(t, uint(written), packSize)
rtest.Equals(t, headerSize, int(hdrSize))
var buf []byte