[feature] add per-uri dereferencer locks (#2291)

1 files changed, 9 insertions, 8 deletions

diff --git a/internal/federation/dereferencing/emoji.go b/internal/federation/dereferencing/emoji.go
index 2d86da663..1bf19d2fd 100644
--- a/internal/federation/dereferencing/emoji.go
+++ b/internal/federation/dereferencing/emoji.go
@@ -36,8 +36,15 @@ func (d *Dereferencer) GetRemoteEmoji(ctx context.Context, requestingUsername st
 		processingEmoji *media.ProcessingEmoji
 	)
 
+	// Ensure we have been passed a valid URL.
+	derefURI, err := url.Parse(remoteURL)
+	if err != nil {
+		return nil, fmt.Errorf("GetRemoteEmoji: error parsing url for emoji %s: %s", shortcodeDomain, err)
+	}
+
 	// Acquire lock for derefs map.
-	unlock := d.derefEmojisMu.Lock()
+	unlock := d.state.FedLocks.Lock(remoteURL)
+	unlock = doOnce(unlock)
 	defer unlock()
 
 	// first check if we're already processing this emoji
@@ -51,11 +58,6 @@ func (d *Dereferencer) GetRemoteEmoji(ctx context.Context, requestingUsername st
 			return nil, fmt.Errorf("GetRemoteEmoji: error creating transport to fetch emoji %s: %s", shortcodeDomain, err)
 		}
 
-		derefURI, err := url.Parse(remoteURL)
-		if err != nil {
-			return nil, fmt.Errorf("GetRemoteEmoji: error parsing url for emoji %s: %s", shortcodeDomain, err)
-		}
-
 		dataFunc := func(innerCtx context.Context) (io.ReadCloser, int64, error) {
 			return t.DereferenceMedia(innerCtx, derefURI)
 		}
@@ -75,7 +77,7 @@ func (d *Dereferencer) GetRemoteEmoji(ctx context.Context, requestingUsername st
 
 	defer func() {
 		// On exit safely remove emoji from map.
-		unlock := d.derefEmojisMu.Lock()
+		unlock := d.state.FedLocks.Lock(remoteURL)
 		delete(d.derefEmojis, shortcodeDomain)
 		unlock()
 	}()
@@ -95,7 +97,6 @@ func (d *Dereferencer) populateEmojis(ctx context.Context, rawEmojis []*gtsmodel
 	// * the shortcode of the emoji
 	// * the remote URL of the image
 	// This should be enough to dereference the emoji
-
 	gotEmojis := make([]*gtsmodel.Emoji, 0, len(rawEmojis))
 
 	for _, e := range rawEmojis {