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authorMiguel Molina <miguel@erizocosmi.co>2018-07-19 15:20:10 +0200
committerMiguel Molina <miguel@erizocosmi.co>2018-07-19 15:20:10 +0200
commit009f1069a1248c1e9189a9e4c342f6d017156ec4 (patch)
treeac984b72e7c54160b0b154bffd4474f96ae5028e /plumbing/format/packfile/index.go
parent9f00789688d26191a987fdec8bc2678362ec4453 (diff)
downloadgo-git-009f1069a1248c1e9189a9e4c342f6d017156ec4.tar.gz
plumbing/format/idxfile: add new Index and MemoryIndex
Signed-off-by: Miguel Molina <miguel@erizocosmi.co>
Diffstat (limited to 'plumbing/format/packfile/index.go')
-rw-r--r--plumbing/format/packfile/index.go125
1 files changed, 0 insertions, 125 deletions
diff --git a/plumbing/format/packfile/index.go b/plumbing/format/packfile/index.go
deleted file mode 100644
index 021b2d1..0000000
--- a/plumbing/format/packfile/index.go
+++ /dev/null
@@ -1,125 +0,0 @@
-package packfile
-
-import (
- "sort"
-
- "gopkg.in/src-d/go-git.v4/plumbing"
- "gopkg.in/src-d/go-git.v4/plumbing/format/idxfile"
-)
-
-// Index is an in-memory representation of a packfile index.
-// This uses idxfile.Idxfile under the hood to obtain indexes from .idx files
-// or to store them.
-type Index struct {
- byHash map[plumbing.Hash]*idxfile.Entry
- byOffset []*idxfile.Entry // sorted by their offset
-}
-
-// NewIndex creates a new empty index with the given size. Size is a hint and
-// can be 0. It is recommended to set it to the number of objects to be indexed
-// if it is known beforehand (e.g. reading from a packfile).
-func NewIndex(size int) *Index {
- return &Index{
- byHash: make(map[plumbing.Hash]*idxfile.Entry, size),
- byOffset: make([]*idxfile.Entry, 0, size),
- }
-}
-
-// NewIndexFromIdxFile creates a new Index from an idxfile.IdxFile.
-func NewIndexFromIdxFile(idxf *idxfile.Idxfile) *Index {
- idx := &Index{
- byHash: make(map[plumbing.Hash]*idxfile.Entry, idxf.ObjectCount),
- byOffset: make([]*idxfile.Entry, 0, idxf.ObjectCount),
- }
- sorted := true
- for i, e := range idxf.Entries {
- idx.addUnsorted(e)
- if i > 0 && idx.byOffset[i-1].Offset >= e.Offset {
- sorted = false
- }
- }
-
- // If the idxfile was loaded from a regular packfile index
- // then it will already be in offset order, in which case we
- // can avoid doing a relatively expensive idempotent sort.
- if !sorted {
- sort.Sort(orderByOffset(idx.byOffset))
- }
-
- return idx
-}
-
-// orderByOffset is a sort.Interface adapter that arranges
-// a slice of entries by their offset.
-type orderByOffset []*idxfile.Entry
-
-func (o orderByOffset) Len() int { return len(o) }
-func (o orderByOffset) Less(i, j int) bool { return o[i].Offset < o[j].Offset }
-func (o orderByOffset) Swap(i, j int) { o[i], o[j] = o[j], o[i] }
-
-// Add adds a new Entry with the given values to the index.
-func (idx *Index) Add(h plumbing.Hash, offset uint64, crc32 uint32) {
- e := &idxfile.Entry{
- Hash: h,
- Offset: offset,
- CRC32: crc32,
- }
- idx.byHash[e.Hash] = e
-
- // Find the right position in byOffset.
- // Look for the first position whose offset is *greater* than e.Offset.
- i := sort.Search(len(idx.byOffset), func(i int) bool {
- return idx.byOffset[i].Offset > offset
- })
- if i == len(idx.byOffset) {
- // Simple case: add it to the end.
- idx.byOffset = append(idx.byOffset, e)
- return
- }
- // Harder case: shift existing entries down by one to make room.
- // Append a nil entry first so we can use existing capacity in case
- // the index was carefully preallocated.
- idx.byOffset = append(idx.byOffset, nil)
- copy(idx.byOffset[i+1:], idx.byOffset[i:len(idx.byOffset)-1])
- idx.byOffset[i] = e
-}
-
-func (idx *Index) addUnsorted(e *idxfile.Entry) {
- idx.byHash[e.Hash] = e
- idx.byOffset = append(idx.byOffset, e)
-}
-
-// LookupHash looks an entry up by its hash. An idxfile.Entry is returned and
-// a bool, which is true if it was found or false if it wasn't.
-func (idx *Index) LookupHash(h plumbing.Hash) (*idxfile.Entry, bool) {
- e, ok := idx.byHash[h]
- return e, ok
-}
-
-// LookupHash looks an entry up by its offset in the packfile. An idxfile.Entry
-// is returned and a bool, which is true if it was found or false if it wasn't.
-func (idx *Index) LookupOffset(offset uint64) (*idxfile.Entry, bool) {
- i := sort.Search(len(idx.byOffset), func(i int) bool {
- return idx.byOffset[i].Offset >= offset
- })
- if i >= len(idx.byOffset) || idx.byOffset[i].Offset != offset {
- return nil, false // not present
- }
- return idx.byOffset[i], true
-}
-
-// Size returns the number of entries in the index.
-func (idx *Index) Size() int {
- return len(idx.byHash)
-}
-
-// ToIdxFile converts the index to an idxfile.Idxfile, which can then be used
-// to serialize.
-func (idx *Index) ToIdxFile() *idxfile.Idxfile {
- idxf := idxfile.NewIdxfile()
- for _, e := range idx.byHash {
- idxf.Entries = append(idxf.Entries, e)
- }
-
- return idxf
-}