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package pack
import (
"bytes"
"crypto/sha1"
"encoding/binary"
"fmt"
"testing"
"github.com/stretchr/testify/assert"
)
var (
idx *Index
)
func TestIndexEntrySearch(t *testing.T) {
e, err := idx.Entry([]byte{
0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1,
0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1, 0x1,
})
assert.NoError(t, err)
assert.EqualValues(t, 6, e.PackOffset)
}
func TestIndexEntrySearchClampLeft(t *testing.T) {
e, err := idx.Entry([]byte{
0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
})
assert.NoError(t, err)
assert.EqualValues(t, 0, e.PackOffset)
}
func TestIndexEntrySearchClampRight(t *testing.T) {
e, err := idx.Entry([]byte{
0xff, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
})
assert.NoError(t, err)
assert.EqualValues(t, 0x4ff, e.PackOffset)
}
func TestIndexSearchOutOfBounds(t *testing.T) {
e, err := idx.Entry([]byte{
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
})
assert.True(t, IsNotFound(err), "expected err to be 'not found'")
assert.Nil(t, e)
}
func TestIndexEntryNotFound(t *testing.T) {
e, err := idx.Entry([]byte{
0x1, 0x6, 0x6, 0x6, 0x6, 0x6, 0x6, 0x6, 0x6, 0x6,
0x6, 0x6, 0x6, 0x6, 0x6, 0x6, 0x6, 0x6, 0x6, 0x6,
})
assert.True(t, IsNotFound(err), "expected err to be 'not found'")
assert.Nil(t, e)
}
func TestIndexCount(t *testing.T) {
fanout := make([]uint32, 256)
for i := 0; i < len(fanout); i++ {
fanout[i] = uint32(i)
}
idx := &Index{fanout: fanout}
assert.EqualValues(t, 255, idx.Count())
}
func TestIndexIsNotFound(t *testing.T) {
assert.True(t, IsNotFound(errNotFound),
"expected 'errNotFound' to satisfy 'IsNotFound()'")
}
func TestIndexIsNotFoundForOtherErrors(t *testing.T) {
assert.False(t, IsNotFound(fmt.Errorf("gitobj/pack: misc")),
"expected 'err' not to satisfy 'IsNotFound()'")
}
// init generates some fixture data and then constructs an *Index instance using
// it.
func init() {
// eps is the number of SHA1 names generated under each 0x<t> slot.
const eps = 5
hdr := []byte{
0xff, 0x74, 0x4f, 0x63, // Index file v2+ magic header
0x00, 0x00, 0x00, 0x02, // 4-byte version indicator
}
// Create a fanout table using uint32s (later marshalled using
// binary.BigEndian).
//
// Since we have an even distribution of SHA1s in the generated index,
// each entry will increase by the number of entries per slot (see: eps
// above).
fanout := make([]uint32, indexFanoutEntries)
for i := 0; i < len(fanout); i++ {
// Begin the index at (i+1), since the fanout table mandates
// objects less than the value at index "i".
fanout[i] = uint32((i + 1) * eps)
}
offs := make([]uint32, 0, 256*eps)
crcs := make([]uint32, 0, 256*eps)
names := make([][]byte, 0, 256*eps)
for i := 0; i < 256; i++ {
// For each name, generate a unique SHA using the prefix "i",
// and then suffix "j".
//
// In other words, when i=1, we will generate:
// []byte{0x1 0x0 0x0 0x0 ...}
// []byte{0x1 0x1 0x1 0x1 ...}
// []byte{0x1 0x2 0x2 0x2 ...}
//
// and etc.
for j := 0; j < eps; j++ {
var sha [20]byte
sha[0] = byte(i)
for r := 1; r < len(sha); r++ {
sha[r] = byte(j)
}
cpy := make([]byte, len(sha))
copy(cpy, sha[:])
names = append(names, cpy)
offs = append(offs, uint32((i*eps)+j))
crcs = append(crcs, 0)
}
}
// Create a buffer to hold the index contents:
buf := bytes.NewBuffer(hdr)
// Write each value in the fanout table using a 32bit network byte-order
// integer.
for _, f := range fanout {
binary.Write(buf, binary.BigEndian, f)
}
// Write each SHA1 name to the table next.
for _, name := range names {
buf.Write(name)
}
// Then write each of the CRC values in network byte-order as a 32bit
// unsigned integer.
for _, crc := range crcs {
binary.Write(buf, binary.BigEndian, crc)
}
// Do the same with the offsets.
for _, off := range offs {
binary.Write(buf, binary.BigEndian, off)
}
idx = &Index{
fanout: fanout,
// version is unimportant here, use V2 since it's more common in
// the wild.
version: &V2{hash: sha1.New()},
// *bytes.Buffer does not implement io.ReaderAt, but
// *bytes.Reader does.
//
// Call (*bytes.Buffer).Bytes() to get the data, and then
// construct a new *bytes.Reader with it to implement
// io.ReaderAt.
r: bytes.NewReader(buf.Bytes()),
}
}
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