WIP - Implement branchable collections

internal/core/crdt/collection.go

@@ -0,0 +1,67 @@
+// Copyright 2024 Democratized Data Foundation
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.txt.
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0, included in the file
+// licenses/APL.txt.
+
+package crdt
+
+import (
+	"context"
+
+	"github.com/sourcenetwork/defradb/datastore"
+	"github.com/sourcenetwork/defradb/internal/core"
+)
+
+type Collection struct {
+	store datastore.DSReaderWriter
+	// schemaVersionKey is the schema version datastore key at the time of commit.
+	//
+	// It can be used to identify the collection datastructure state at the time of commit.
+	schemaVersionKey core.CollectionSchemaVersionKey
+}
+
+var _ core.ReplicatedData = (*Collection)(nil)
+
+func NewCollection(store datastore.DSReaderWriter, schemaVersionKey core.CollectionSchemaVersionKey) *Collection {
+	return &Collection{
+		store:            store,
+		schemaVersionKey: schemaVersionKey,
+	}
+}
+
+func (d *Collection) Merge(ctx context.Context, other core.Delta) error {
+	panic("todo")
+}
+
+func (d *Collection) Append() *CollectionDelta {
+	panic("todo")
+}
+
+type CollectionDelta struct {
+	Priority uint64
+	// todo: This is temporary pending a global collection id (link to ticket)
+	SchemaVersionID string
+}
+
+var _ core.Delta = (*CollectionDelta)(nil)
+
+func (delta *CollectionDelta) IPLDSchemaBytes() []byte {
+	return []byte(`
+	type CollectionDelta struct {
+		priority  		Int
+		schemaVersionID String
+	}`)
+}
+
+func (d *CollectionDelta) GetPriority() uint64 {
+	panic("todo")
+}
+
+func (d *CollectionDelta) SetPriority(uint64) {
+	panic("todo")
+}