bring in khatru and eventstore.

eventstore/slicestore/lib.go

@@ -0,0 +1,157 @@
+package slicestore
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"sync"
+
+	"github.com/fiatjaf/eventstore"
+	"github.com/fiatjaf/eventstore/internal"
+	"github.com/nbd-wtf/go-nostr"
+	"golang.org/x/exp/slices"
+)
+
+var _ eventstore.Store = (*SliceStore)(nil)
+
+type SliceStore struct {
+	sync.Mutex
+	internal []*nostr.Event
+
+	MaxLimit int
+}
+
+func (b *SliceStore) Init() error {
+	b.internal = make([]*nostr.Event, 0, 5000)
+	if b.MaxLimit == 0 {
+		b.MaxLimit = 500
+	}
+	return nil
+}
+
+func (b *SliceStore) Close() {}
+
+func (b *SliceStore) QueryEvents(ctx context.Context, filter nostr.Filter) (chan *nostr.Event, error) {
+	ch := make(chan *nostr.Event)
+	if filter.Limit > b.MaxLimit || (filter.Limit == 0 && !filter.LimitZero) {
+		filter.Limit = b.MaxLimit
+	}
+
+	// efficiently determine where to start and end
+	start := 0
+	end := len(b.internal)
+	if filter.Until != nil {
+		start, _ = slices.BinarySearchFunc(b.internal, *filter.Until, eventTimestampComparator)
+	}
+	if filter.Since != nil {
+		end, _ = slices.BinarySearchFunc(b.internal, *filter.Since, eventTimestampComparator)
+	}
+
+	// ham
+	if end < start {
+		close(ch)
+		return ch, nil
+	}
+
+	count := 0
+	go func() {
+		for _, event := range b.internal[start:end] {
+			if count == filter.Limit {
+				break
+			}
+
+			if filter.Matches(event) {
+				select {
+				case ch <- event:
+				case <-ctx.Done():
+					return
+				}
+				count++
+			}
+		}
+		close(ch)
+	}()
+	return ch, nil
+}
+
+func (b *SliceStore) CountEvents(ctx context.Context, filter nostr.Filter) (int64, error) {
+	var val int64
+	for _, event := range b.internal {
+		if filter.Matches(event) {
+			val++
+		}
+	}
+	return val, nil
+}
+
+func (b *SliceStore) SaveEvent(ctx context.Context, evt *nostr.Event) error {
+	idx, found := slices.BinarySearchFunc(b.internal, evt, eventComparator)
+	if found {
+		return eventstore.ErrDupEvent
+	}
+	// let's insert at the correct place in the array
+	b.internal = append(b.internal, evt) // bogus
+	copy(b.internal[idx+1:], b.internal[idx:])
+	b.internal[idx] = evt
+
+	return nil
+}
+
+func (b *SliceStore) DeleteEvent(ctx context.Context, evt *nostr.Event) error {
+	idx, found := slices.BinarySearchFunc(b.internal, evt, eventComparator)
+	if !found {
+		// we don't have this event
+		return nil
+	}
+
+	// we have it
+	copy(b.internal[idx:], b.internal[idx+1:])
+	b.internal = b.internal[0 : len(b.internal)-1]
+	return nil
+}
+
+func (b *SliceStore) ReplaceEvent(ctx context.Context, evt *nostr.Event) error {
+	b.Lock()
+	defer b.Unlock()
+
+	filter := nostr.Filter{Limit: 1, Kinds: []int{evt.Kind}, Authors: []string{evt.PubKey}}
+	if nostr.IsAddressableKind(evt.Kind) {
+		filter.Tags = nostr.TagMap{"d": []string{evt.Tags.GetD()}}
+	}
+
+	ch, err := b.QueryEvents(ctx, filter)
+	if err != nil {
+		return fmt.Errorf("failed to query before replacing: %w", err)
+	}
+
+	shouldStore := true
+	for previous := range ch {
+		if internal.IsOlder(previous, evt) {
+			if err := b.DeleteEvent(ctx, previous); err != nil {
+				return fmt.Errorf("failed to delete event for replacing: %w", err)
+			}
+		} else {
+			shouldStore = false
+		}
+	}
+
+	if shouldStore {
+		if err := b.SaveEvent(ctx, evt); err != nil && err != eventstore.ErrDupEvent {
+			return fmt.Errorf("failed to save: %w", err)
+		}
+	}
+
+	return nil
+}
+
+func eventTimestampComparator(e *nostr.Event, t nostr.Timestamp) int {
+	return int(t) - int(e.CreatedAt)
+}
+
+func eventComparator(a *nostr.Event, b *nostr.Event) int {
+	c := int(b.CreatedAt) - int(a.CreatedAt)
+	if c != 0 {
+		return c
+	}
+	return strings.Compare(b.ID, a.ID)
+}