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// 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 stream
import (
"context"
"errors"
"fmt"
"codeberg.org/gruf/go-kv"
"github.com/superseriousbusiness/gotosocial/internal/gtserror"
"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
"github.com/superseriousbusiness/gotosocial/internal/id"
"github.com/superseriousbusiness/gotosocial/internal/log"
"github.com/superseriousbusiness/gotosocial/internal/stream"
)
// Open returns a new Stream for the given account, which will contain a channel for passing messages back to the caller.
func (p *Processor) Open(ctx context.Context, account *gtsmodel.Account, streamType string) (*stream.Stream, gtserror.WithCode) {
l := log.WithContext(ctx).WithFields(kv.Fields{
{"account", account.ID},
{"streamType", streamType},
}...)
l.Debug("received open stream request")
var (
streamID string
err error
)
// Each stream needs a unique ID so we know to close it.
streamID, err = id.NewRandomULID()
if err != nil {
return nil, gtserror.NewErrorInternalError(fmt.Errorf("error generating stream id: %w", err))
}
// Each stream can be subscibed to multiple types.
// Record them in a set, and include the initial one
// if it was given to us.
streamTypes := map[string]any{}
if streamType != "" {
streamTypes[streamType] = true
}
newStream := &stream.Stream{
ID: streamID,
StreamTypes: streamTypes,
Messages: make(chan *stream.Message, 100),
Hangup: make(chan interface{}, 1),
Connected: true,
}
go p.waitToCloseStream(account, newStream)
v, ok := p.streamMap.Load(account.ID)
if ok {
// There is an entry in the streamMap
// for this account. Parse it out.
streamsForAccount, ok := v.(*stream.StreamsForAccount)
if !ok {
return nil, gtserror.NewErrorInternalError(errors.New("stream map error"))
}
// Append new stream to existing entry.
streamsForAccount.Lock()
streamsForAccount.Streams = append(streamsForAccount.Streams, newStream)
streamsForAccount.Unlock()
} else {
// There is no entry in the streamMap for
// this account yet. Create one and store it.
p.streamMap.Store(account.ID, &stream.StreamsForAccount{
Streams: []*stream.Stream{
newStream,
},
})
}
return newStream, nil
}
// waitToCloseStream waits until the hangup channel is closed for the given stream.
// It then iterates through the map of streams stored by the processor, removes the stream from it,
// and then closes the messages channel of the stream to indicate that the channel should no longer be read from.
func (p *Processor) waitToCloseStream(account *gtsmodel.Account, thisStream *stream.Stream) {
<-thisStream.Hangup // wait for a hangup message
// lock the stream to prevent more messages being put in it while we work
thisStream.Lock()
defer thisStream.Unlock()
// indicate the stream is no longer connected
thisStream.Connected = false
// load and parse the entry for this account from the stream map
v, ok := p.streamMap.Load(account.ID)
if !ok || v == nil {
return
}
streamsForAccount, ok := v.(*stream.StreamsForAccount)
if !ok {
return
}
// lock the streams for account while we remove this stream from its slice
streamsForAccount.Lock()
defer streamsForAccount.Unlock()
// put everything into modified streams *except* the stream we're removing
modifiedStreams := []*stream.Stream{}
for _, s := range streamsForAccount.Streams {
if s.ID != thisStream.ID {
modifiedStreams = append(modifiedStreams, s)
}
}
streamsForAccount.Streams = modifiedStreams
// finally close the messages channel so no more messages can be read from it
close(thisStream.Messages)
}
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