package commitgraph
import (
"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]int
}
// NewMemoryIndex creates in-memory commit graph representation
func NewMemoryIndex() *MemoryIndex {
return &MemoryIndex{
indexMap: make(map[plumbing.Hash]int),
}
}
// GetIndexByHash gets the index in the commit graph from commit hash, if available
func (mi *MemoryIndex) GetIndexByHash(h plumbing.Hash) (int, error) {
i, ok := mi.indexMap[h]
if ok {
return i, nil
}
return 0, plumbing.ErrObjectNotFound
}
// GetCommitDataByIndex gets the commit node from the commit graph using index
// obtained from child node, if available
func (mi *MemoryIndex) GetCommitDataByIndex(i int) (*CommitData, error) {
if i >= len(mi.commitData) {
return nil, plumbing.ErrObjectNotFound
}
commitData := mi.commitData[i]
// Map parent hashes to parent indexes
if commitData.ParentIndexes == nil {
parentIndexes := make([]int, 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, 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, commitData *CommitData) {
// The parent indexes are calculated lazily in GetNodeByIndex
// which allows adding nodes out of order as long as all parents
// are eventually resolved
commitData.ParentIndexes = nil
mi.indexMap[hash] = len(mi.commitData)
mi.commitData = append(mi.commitData, commitData)
}
