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package v2
import (
"math"
"github.com/go-git/go-git/v5/plumbing"
)
// MemoryIndex provides a way to build the commit-graph in memory
// for later encoding to file.
type MemoryIndex struct {
commitData []commitData
indexMap map[plumbing.Hash]uint32
hasGenerationV2 bool
}
type commitData struct {
Hash plumbing.Hash
*CommitData
}
// NewMemoryIndex creates in-memory commit graph representation
func NewMemoryIndex() *MemoryIndex {
return &MemoryIndex{
indexMap: make(map[plumbing.Hash]uint32),
hasGenerationV2: true,
}
}
// GetIndexByHash gets the index in the commit graph from commit hash, if available
func (mi *MemoryIndex) GetIndexByHash(h plumbing.Hash) (uint32, error) {
i, ok := mi.indexMap[h]
if ok {
return i, nil
}
return 0, plumbing.ErrObjectNotFound
}
// GetHashByIndex gets the hash given an index in the commit graph
func (mi *MemoryIndex) GetHashByIndex(i uint32) (plumbing.Hash, error) {
if i >= uint32(len(mi.commitData)) {
return plumbing.ZeroHash, plumbing.ErrObjectNotFound
}
return mi.commitData[i].Hash, nil
}
// GetCommitDataByIndex gets the commit node from the commit graph using index
// obtained from child node, if available
func (mi *MemoryIndex) GetCommitDataByIndex(i uint32) (*CommitData, error) {
if i >= uint32(len(mi.commitData)) {
return nil, plumbing.ErrObjectNotFound
}
commitData := mi.commitData[i]
// Map parent hashes to parent indexes
if commitData.ParentIndexes == nil {
parentIndexes := make([]uint32, len(commitData.ParentHashes))
for i, parentHash := range commitData.ParentHashes {
var err error
if parentIndexes[i], err = mi.GetIndexByHash(parentHash); err != nil {
return nil, err
}
}
commitData.ParentIndexes = parentIndexes
}
return commitData.CommitData, nil
}
// Hashes returns all the hashes that are available in the index
func (mi *MemoryIndex) Hashes() []plumbing.Hash {
hashes := make([]plumbing.Hash, 0, len(mi.indexMap))
for k := range mi.indexMap {
hashes = append(hashes, k)
}
return hashes
}
// Add adds new node to the memory index
func (mi *MemoryIndex) Add(hash plumbing.Hash, data *CommitData) {
// The parent indexes are calculated lazily in GetNodeByIndex
// which allows adding nodes out of order as long as all parents
// are eventually resolved
data.ParentIndexes = nil
mi.indexMap[hash] = uint32(len(mi.commitData))
mi.commitData = append(mi.commitData, commitData{Hash: hash, CommitData: data})
if data.GenerationV2 == math.MaxUint64 { // if GenerationV2 is not available reset it to zero
data.GenerationV2 = 0
}
mi.hasGenerationV2 = mi.hasGenerationV2 && data.GenerationV2 != 0
}
func (mi *MemoryIndex) HasGenerationV2() bool {
return mi.hasGenerationV2
}
// Close closes the index
func (mi *MemoryIndex) Close() error {
return nil
}
func (mi *MemoryIndex) MaximumNumberOfHashes() uint32 {
return uint32(len(mi.indexMap))
}
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