[feature] Add List functionality (#1802)

* start working on lists

* further list work

* test list db functions nicely

* more work on lists

* peepoopeepoo

* poke

* start list timeline func

* we're getting there lads

* couldn't be me working on stuff... could it?

* hook up handlers

* fiddling

* weeee

* woah

* screaming, pissing

* fix streaming being a whiny baby

* lint, small test fix, swagger

* tidying up, testing

* fucked! by the linter

* move timelines to state like a boss

* add timeline start to tests using state

* invalidate lists

internal/processing/list/util.go

@@ -0,0 +1,85 @@
+// 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 list
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	apimodel "github.com/superseriousbusiness/gotosocial/internal/api/model"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+)
+
+// getList is a shortcut to get one list from the database and
+// check that it's owned by the given accountID. Will return
+// appropriate errors so caller doesn't need to bother.
+func (p *Processor) getList(ctx context.Context, accountID string, listID string) (*gtsmodel.List, gtserror.WithCode) {
+	list, err := p.state.DB.GetListByID(ctx, listID)
+	if err != nil {
+		if errors.Is(err, db.ErrNoEntries) {
+			// List doesn't seem to exist.
+			return nil, gtserror.NewErrorNotFound(err)
+		}
+		// Real database error.
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+
+	if list.AccountID != accountID {
+		err = fmt.Errorf("list with id %s does not belong to account %s", list.ID, accountID)
+		return nil, gtserror.NewErrorNotFound(err)
+	}
+
+	return list, nil
+}
+
+// apiList is a shortcut to return the API version of the given
+// list, or return an appropriate error if conversion fails.
+func (p *Processor) apiList(ctx context.Context, list *gtsmodel.List) (*apimodel.List, gtserror.WithCode) {
+	apiList, err := p.tc.ListToAPIList(ctx, list)
+	if err != nil {
+		return nil, gtserror.NewErrorInternalError(fmt.Errorf("error converting list to api: %w", err))
+	}
+
+	return apiList, nil
+}
+
+// isInList check if thisID is equal to the result of thatID
+// for any entry in the given list.
+//
+// Will return the id of the listEntry if true, empty if false,
+// or an error if the result of thatID returns an error.
+func isInList(
+	list *gtsmodel.List,
+	thisID string,
+	getThatID func(listEntry *gtsmodel.ListEntry) (string, error),
+) (string, error) {
+	for _, listEntry := range list.ListEntries {
+		thatID, err := getThatID(listEntry)
+		if err != nil {
+			return "", err
+		}
+
+		if thisID == thatID {
+			return listEntry.ID, nil
+		}
+	}
+	return "", nil
+}