1 files changed, 243 insertions, 0 deletions
diff --git a/internal/db/bundb/relationship_follow.go b/internal/db/bundb/relationship_follow.go
new file mode 100644
index 000000000..4a315d116
--- /dev/null
+++ b/internal/db/bundb/relationship_follow.go
@@ -0,0 +1,243 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// 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 bundb
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtscontext"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/log"
+	"github.com/uptrace/bun"
+)
+
+func (r *relationshipDB) GetFollowByID(ctx context.Context, id string) (*gtsmodel.Follow, error) {
+	return r.getFollow(
+		ctx,
+		"ID",
+		func(follow *gtsmodel.Follow) error {
+			return r.conn.NewSelect().
+				Model(follow).
+				Where("? = ?", bun.Ident("id"), id).
+				Scan(ctx)
+		},
+		id,
+	)
+}
+
+func (r *relationshipDB) GetFollowByURI(ctx context.Context, uri string) (*gtsmodel.Follow, error) {
+	return r.getFollow(
+		ctx,
+		"URI",
+		func(follow *gtsmodel.Follow) error {
+			return r.conn.NewSelect().
+				Model(follow).
+				Where("? = ?", bun.Ident("uri"), uri).
+				Scan(ctx)
+		},
+		uri,
+	)
+}
+
+func (r *relationshipDB) GetFollow(ctx context.Context, sourceAccountID string, targetAccountID string) (*gtsmodel.Follow, error) {
+	return r.getFollow(
+		ctx,
+		"AccountID.TargetAccountID",
+		func(follow *gtsmodel.Follow) error {
+			return r.conn.NewSelect().
+				Model(follow).
+				Where("? = ?", bun.Ident("account_id"), sourceAccountID).
+				Where("? = ?", bun.Ident("target_account_id"), targetAccountID).
+				Scan(ctx)
+		},
+		sourceAccountID,
+		targetAccountID,
+	)
+}
+
+func (r *relationshipDB) GetFollowsByIDs(ctx context.Context, ids []string) ([]*gtsmodel.Follow, error) {
+	// Preallocate slice of expected length.
+	follows := make([]*gtsmodel.Follow, 0, len(ids))
+
+	for _, id := range ids {
+		// Fetch follow model for this ID.
+		follow, err := r.GetFollowByID(ctx, id)
+		if err != nil {
+			log.Errorf(ctx, "error getting follow %q: %v", id, err)
+			continue
+		}
+
+		// Append to return slice.
+		follows = append(follows, follow)
+	}
+
+	return follows, nil
+}
+
+func (r *relationshipDB) IsFollowing(ctx context.Context, sourceAccountID string, targetAccountID string) (bool, db.Error) {
+	follow, err := r.GetFollow(
+		gtscontext.SetBarebones(ctx),
+		sourceAccountID,
+		targetAccountID,
+	)
+	if err != nil && !errors.Is(err, db.ErrNoEntries) {
+		return false, err
+	}
+	return (follow != nil), nil
+}
+
+func (r *relationshipDB) IsMutualFollowing(ctx context.Context, accountID1 string, accountID2 string) (bool, db.Error) {
+	// make sure account 1 follows account 2
+	f1, err := r.IsFollowing(ctx,
+		accountID1,
+		accountID2,
+	)
+	if !f1 /* f1 = false when err != nil */ {
+		return false, err
+	}
+
+	// make sure account 2 follows account 1
+	f2, err := r.IsFollowing(ctx,
+		accountID2,
+		accountID1,
+	)
+	if !f2 /* f2 = false when err != nil */ {
+		return false, err
+	}
+
+	return true, nil
+}
+
+func (r *relationshipDB) getFollow(ctx context.Context, lookup string, dbQuery func(*gtsmodel.Follow) error, keyParts ...any) (*gtsmodel.Follow, error) {
+	// Fetch follow from database cache with loader callback
+	follow, err := r.state.Caches.GTS.Follow().Load(lookup, func() (*gtsmodel.Follow, error) {
+		var follow gtsmodel.Follow
+
+		// Not cached! Perform database query
+		if err := dbQuery(&follow); err != nil {
+			return nil, r.conn.ProcessError(err)
+		}
+
+		return &follow, nil
+	}, keyParts...)
+	if err != nil {
+		// error already processed
+		return nil, err
+	}
+
+	if gtscontext.Barebones(ctx) {
+		// Only a barebones model was requested.
+		return follow, nil
+	}
+
+	// Set the follow source account
+	follow.Account, err = r.state.DB.GetAccountByID(
+		gtscontext.SetBarebones(ctx),
+		follow.AccountID,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("error getting follow source account: %w", err)
+	}
+
+	// Set the follow target account
+	follow.TargetAccount, err = r.state.DB.GetAccountByID(
+		gtscontext.SetBarebones(ctx),
+		follow.TargetAccountID,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("error getting follow target account: %w", err)
+	}
+
+	return follow, nil
+}
+
+func (r *relationshipDB) PutFollow(ctx context.Context, follow *gtsmodel.Follow) error {
+	err := r.state.Caches.GTS.Follow().Store(follow, func() error {
+		_, err := r.conn.NewInsert().Model(follow).Exec(ctx)
+		return r.conn.ProcessError(err)
+	})
+	if err != nil {
+		return err
+	}
+
+	// Invalidate follow origin account ID cached visibility.
+	r.state.Caches.Visibility.Invalidate("ItemID", follow.AccountID)
+	r.state.Caches.Visibility.Invalidate("RequesterID", follow.AccountID)
+
+	// Invalidate follow target account ID cached visibility.
+	r.state.Caches.Visibility.Invalidate("ItemID", follow.TargetAccountID)
+	r.state.Caches.Visibility.Invalidate("RequesterID", follow.TargetAccountID)
+
+	return nil
+}
+
+func (r *relationshipDB) DeleteFollowByID(ctx context.Context, id string) error {
+	if _, err := r.conn.NewDelete().
+		Table("follows").
+		Where("? = ?", bun.Ident("id"), id).
+		Exec(ctx); err != nil {
+		return r.conn.ProcessError(err)
+	}
+
+	// Invalidate follow from cache lookups.
+	r.state.Caches.GTS.Follow().Invalidate("ID", id)
+
+	return nil
+}
+
+func (r *relationshipDB) DeleteFollowByURI(ctx context.Context, uri string) error {
+	if _, err := r.conn.NewDelete().
+		Table("follows").
+		Where("? = ?", bun.Ident("uri"), uri).
+		Exec(ctx); err != nil {
+		return r.conn.ProcessError(err)
+	}
+
+	// Invalidate follow from cache lookups.
+	r.state.Caches.GTS.Follow().Invalidate("URI", uri)
+
+	return nil
+}
+
+func (r *relationshipDB) DeleteAccountFollows(ctx context.Context, accountID string) error {
+	var followIDs []string
+
+	if _, err := r.conn.
+		NewDelete().
+		Table("follows").
+		WhereOr("? = ? OR ? = ?",
+			bun.Ident("account_id"),
+			accountID,
+			bun.Ident("target_account_id"),
+			accountID,
+		).
+		Returning("?", bun.Ident("id")).
+		Exec(ctx, &followIDs); err != nil {
+		return r.conn.ProcessError(err)
+	}
+
+	// Invalidate each returned ID.
+	for _, id := range followIDs {
+		r.state.Caches.GTS.Follow().Invalidate("ID", id)
+	}
+
+	return nil
+}