package blockstore import ( "context" blocks "github.com/ipfs/go-block-format" "github.com/ipfs/go-cid" ) type unionBlockstore []Blockstore // Union returns an unioned blockstore. // // * Reads return from the first blockstore that has the value, querying in the // supplied order. // * Writes (puts and deltes) are broadcast to all stores. // func Union(stores ...Blockstore) Blockstore { return unionBlockstore(stores) } func (m unionBlockstore) Has(cid cid.Cid) (has bool, err error) { for _, bs := range m { if has, err = bs.Has(cid); has || err != nil { break } } return has, err } func (m unionBlockstore) Get(cid cid.Cid) (blk blocks.Block, err error) { for _, bs := range m { if blk, err = bs.Get(cid); err == nil || err != ErrNotFound { break } } return blk, err } func (m unionBlockstore) View(cid cid.Cid, callback func([]byte) error) (err error) { for _, bs := range m { if err = bs.View(cid, callback); err == nil || err != ErrNotFound { break } } return err } func (m unionBlockstore) GetSize(cid cid.Cid) (size int, err error) { for _, bs := range m { if size, err = bs.GetSize(cid); err == nil || err != ErrNotFound { break } } return size, err } func (m unionBlockstore) Put(block blocks.Block) (err error) { for _, bs := range m { if err = bs.Put(block); err != nil { break } } return err } func (m unionBlockstore) PutMany(blks []blocks.Block) (err error) { for _, bs := range m { if err = bs.PutMany(blks); err != nil { break } } return err } func (m unionBlockstore) DeleteBlock(cid cid.Cid) (err error) { for _, bs := range m { if err = bs.DeleteBlock(cid); err != nil { break } } return err } func (m unionBlockstore) DeleteMany(cids []cid.Cid) (err error) { for _, bs := range m { if err = bs.DeleteMany(cids); err != nil { break } } return err } func (m unionBlockstore) AllKeysChan(ctx context.Context) (<-chan cid.Cid, error) { // this does not deduplicate; this interface needs to be revisited. outCh := make(chan cid.Cid) go func() { defer close(outCh) for _, bs := range m { ch, err := bs.AllKeysChan(ctx) if err != nil { return } for cid := range ch { outCh <- cid } } }() return outCh, nil } func (m unionBlockstore) HashOnRead(enabled bool) { for _, bs := range m { bs.HashOnRead(enabled) } }