[bugfix] fix possible mutex lockup during streaming code (#2633)

* rewrite Stream{} to use much less mutex locking, update related code

* use new context for the stream context

* ensure stream gets closed on return of writeTo / readFrom WSConn()

* ensure stream write timeout gets cancelled

* remove embedded context type from Stream{}, reformat log messages for consistency

* use c.Request.Context() for context passed into Stream().Open()

* only return 1 boolean, fix tests to expect multiple stream types in messages

* changes to ping logic

* further improved ping logic

* don't export unused function types, update message sending to only include relevant stream type

* ensure stream gets closed 🤦

* update to error log on failed json marshal (instead of panic)

* inverse websocket read error checking to _ignore_ expected close errors

internal/processing/stream/open.go

@@ -19,13 +19,10 @@ 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"
 )
@@ -37,97 +34,5 @@ func (p *Processor) Open(ctx context.Context, account *gtsmodel.Account, streamT
 		{"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)
+	return p.streams.Open(account.ID, streamType), nil
 }