1 files changed, 159 insertions, 0 deletions
diff --git a/internal/db/federating_db.go b/internal/db/federating_db.go
new file mode 100644
index 000000000..5b05967ea
--- /dev/null
+++ b/internal/db/federating_db.go
@@ -0,0 +1,159 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package db
+
+import (
+	"context"
+	"errors"
+	"net/url"
+	"sync"
+
+	"github.com/go-fed/activity/pub"
+	"github.com/go-fed/activity/streams"
+	"github.com/go-fed/activity/streams/vocab"
+	"github.com/superseriousbusiness/gotosocial/internal/config"
+)
+
+// FederatingDB uses the underlying DB interface to implement the go-fed pub.Database interface.
+// It doesn't care what the underlying implementation of the DB interface is, as long as it works.
+type federatingDB struct {
+	locks  *sync.Map
+	db     DB
+	config *config.Config
+}
+
+func newFederatingDB(db DB, config *config.Config) pub.Database {
+	return &federatingDB{
+		locks:  new(sync.Map),
+		db:     db,
+		config: config,
+	}
+}
+
+/*
+   GO-FED DB INTERFACE-IMPLEMENTING FUNCTIONS
+*/
+func (f *federatingDB) Lock(ctx context.Context, id *url.URL) error {
+	// Before any other Database methods are called, the relevant `id`
+	// entries are locked to allow for fine-grained concurrency.
+
+	// Strategy: create a new lock, if stored, continue. Otherwise, lock the
+	// existing mutex.
+	mu := &sync.Mutex{}
+	mu.Lock() // Optimistically lock if we do store it.
+	i, loaded := f.locks.LoadOrStore(id.String(), mu)
+	if loaded {
+		mu = i.(*sync.Mutex)
+		mu.Lock()
+	}
+	return nil
+}
+
+func (f *federatingDB) Unlock(ctx context.Context, id *url.URL) error {
+	// Once Go-Fed is done calling Database methods, the relevant `id`
+	// entries are unlocked.
+
+	i, ok := f.locks.Load(id.String())
+	if !ok {
+		return errors.New("missing an id in unlock")
+	}
+	mu := i.(*sync.Mutex)
+	mu.Unlock()
+	return nil
+}
+
+func (f *federatingDB) InboxContains(ctx context.Context, inbox *url.URL, id *url.URL) (bool, error) {
+	return false, nil
+}
+
+func (f *federatingDB) GetInbox(ctx context.Context, inboxIRI *url.URL) (inbox vocab.ActivityStreamsOrderedCollectionPage, err error) {
+	return nil, nil
+}
+
+func (f *federatingDB) SetInbox(ctx context.Context, inbox vocab.ActivityStreamsOrderedCollectionPage) error {
+	return nil
+}
+
+func (f *federatingDB) Owns(ctx context.Context, id *url.URL) (owns bool, err error) {
+	return id.Host == f.config.Host, nil
+}
+
+func (f *federatingDB) ActorForOutbox(ctx context.Context, outboxIRI *url.URL) (actorIRI *url.URL, err error) {
+	return nil, nil
+}
+
+func (f *federatingDB) ActorForInbox(ctx context.Context, inboxIRI *url.URL) (actorIRI *url.URL, err error) {
+	return nil, nil
+}
+
+func (f *federatingDB) OutboxForInbox(ctx context.Context, inboxIRI *url.URL) (outboxIRI *url.URL, err error) {
+	return nil, nil
+}
+
+func (f *federatingDB) Exists(ctx context.Context, id *url.URL) (exists bool, err error) {
+	return false, nil
+}
+
+func (f *federatingDB) Get(ctx context.Context, id *url.URL) (value vocab.Type, err error) {
+	return nil, nil
+}
+
+func (f *federatingDB) Create(ctx context.Context, asType vocab.Type) error {
+	t, err := streams.NewTypeResolver()
+	if err != nil {
+		return err
+	}
+	if err := t.Resolve(ctx, asType); err != nil {
+		return err
+	}
+	asType.GetTypeName()
+	return nil
+}
+
+func (f *federatingDB) Update(ctx context.Context, asType vocab.Type) error {
+	return nil
+}
+
+func (f *federatingDB) Delete(ctx context.Context, id *url.URL) error {
+	return nil
+}
+
+func (f *federatingDB) GetOutbox(ctx context.Context, outboxIRI *url.URL) (inbox vocab.ActivityStreamsOrderedCollectionPage, err error) {
+	return nil, nil
+}
+
+func (f *federatingDB) SetOutbox(ctx context.Context, outbox vocab.ActivityStreamsOrderedCollectionPage) error {
+	return nil
+}
+
+func (f *federatingDB) NewID(ctx context.Context, t vocab.Type) (id *url.URL, err error) {
+	return nil, nil
+}
+
+func (f *federatingDB) Followers(ctx context.Context, actorIRI *url.URL) (followers vocab.ActivityStreamsCollection, err error) {
+	return nil, nil
+}
+
+func (f *federatingDB) Following(ctx context.Context, actorIRI *url.URL) (followers vocab.ActivityStreamsCollection, err error) {
+	return nil, nil
+}
+
+func (f *federatingDB) Liked(ctx context.Context, actorIRI *url.URL) (followers vocab.ActivityStreamsCollection, err error) {
+	return nil, nil
+}