85 lines
2.2 KiB
Go
85 lines
2.2 KiB
Go
package mmm
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import (
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"encoding/binary"
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"fmt"
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"slices"
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"fiatjaf.com/nostr"
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"github.com/PowerDNS/lmdb-go/lmdb"
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)
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func (il *IndexingLayer) DeleteEvent(id nostr.ID) error {
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il.mmmm.writeMutex.Lock()
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defer il.mmmm.writeMutex.Unlock()
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return il.mmmm.lmdbEnv.Update(func(mmmtxn *lmdb.Txn) error {
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return il.lmdbEnv.Update(func(iltxn *lmdb.Txn) error {
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return il.delete(mmmtxn, iltxn, id)
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})
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})
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}
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func (il *IndexingLayer) delete(mmmtxn *lmdb.Txn, iltxn *lmdb.Txn, id nostr.ID) error {
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zeroRefs := false
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b := il.mmmm
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b.Logger.Debug().Str("layer", il.name).Uint16("il", il.id).Msg("deleting")
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// first in the mmmm txn we check if we have the event still
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val, err := mmmtxn.Get(b.indexId, id[0:8])
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if err != nil {
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if lmdb.IsNotFound(err) {
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// we already do not have this anywhere
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return nil
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}
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return fmt.Errorf("failed to check if we have the event %x: %w", id, err)
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}
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// we have this, but do we have it in the current layer?
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// val is [posb][il_idx][il_idx...]
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pos := positionFromBytes(val[0:12])
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// check references
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currentLayer := binary.BigEndian.AppendUint16(nil, il.id)
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for i := 12; i < len(val); i += 2 {
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if slices.Equal(val[i:i+2], currentLayer) {
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// we will remove the current layer if it's found
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nextval := make([]byte, len(val)-2)
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copy(nextval, val[0:i])
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copy(nextval[i:], val[i+2:])
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if err := mmmtxn.Put(b.indexId, id[0:8], nextval, 0); err != nil {
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return fmt.Errorf("failed to update references for %x: %w", id[:], err)
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}
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// if there are no more layers we will delete everything later
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zeroRefs = len(nextval) == 12
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break
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}
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}
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// load the event so we can compute the indexes
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var evt nostr.Event
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if err := il.mmmm.loadEvent(pos, &evt); err != nil {
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return fmt.Errorf("failed to load event %x when deleting: %w", id[:], err)
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}
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// calculate all index keys we have for this event and delete them
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for k := range il.getIndexKeysForEvent(evt) {
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if err := iltxn.Del(k.dbi, k.key, val[0:12]); err != nil && !lmdb.IsNotFound(err) {
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return fmt.Errorf("index entry %v/%x deletion failed: %w", k.dbi, k.key, err)
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}
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}
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// if there are no more refs we delete the event from the id index and mmap
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if zeroRefs {
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if err := b.purge(mmmtxn, id[0:8], pos); err != nil {
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panic(err)
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}
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}
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return nil
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}
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