Store the entire metadata into extended data, filter the extra data to reduce archive size because we already cache the image in disk cache.

Author: dreampiggy

SDWebImageLinkPlugin/Classes/LPLinkView+WebCache.m

@@ -65,16 +65,14 @@ - (void)sd_setImageWithURL:(nullable NSURL *)url
         if (metadata) {
             // Already exist
         } else if (image) {
-            // Re-generate the metadata from local information
-            metadata = [[LPLinkMetadata alloc] init];
-            metadata.originalURL = url;
-            metadata.URL = imageURL;
             NSData *extendedData = image.sd_extendedData;
+            // Re-generate the metadata from local information
             if (extendedData) {
-                NSString *title = [[NSString alloc] initWithData:extendedData encoding:NSUTF8StringEncoding];
-                if (title.length > 0) {
-                    metadata.title = title;
-                }
+                metadata = [NSKeyedUnarchiver unarchivedObjectOfClass:LPLinkMetadata.class fromData:extendedData error:nil];
+            } else {
+                metadata = [[LPLinkMetadata alloc] init];
+                metadata.originalURL = url;
+                metadata.URL = imageURL;
             }
             // LPLinkMetadata.imageProvider on iOS 13.1 contains bug which cause async query, and not compatible for cell-reusing. Radar FB7462933
             id<LPImageProtocol> linkImage = [[NSClassFromString(LPImageClass) alloc] initWithPlatformImage:image];

SDWebImageLinkPlugin/Classes/SDImageLinkLoader.m

@@ -155,8 +155,11 @@ - (void)fetchImageDataWithProvider:(NSItemProvider *)imageProvider operation:(SD
         if (!image) {
             error = [NSError errorWithDomain:SDWebImageErrorDomain code:SDWebImageErrorBadImageData userInfo:nil];
         } else {
-            LPLinkMetadata *metadata = url.sd_linkMetadata;
-            image.sd_extendedData = [metadata.title dataUsingEncoding:NSUTF8StringEncoding];
+            // The original metadata contains image data and is large, we pick the metadata info only to avoid double cache of image
+            LPLinkMetadata *metadata = [self.class strippedMetadata:url.sd_linkMetadata];
+            // Save the metadata to extended data
+            NSData *extendedData = [NSKeyedArchiver archivedDataWithRootObject:metadata requiringSecureCoding:YES error:nil];
+            image.sd_extendedData = extendedData;
         }
         if (completedBlock) {
             dispatch_main_async_safe(^{
@@ -196,8 +199,11 @@ - (void)fetchImageWithProvider:(NSItemProvider *)imageProvider operation:(SDImag
         if (!image) {
             error = [NSError errorWithDomain:SDWebImageErrorDomain code:SDWebImageErrorBadImageData userInfo:nil];
         } else {
-            LPLinkMetadata *metadata = url.sd_linkMetadata;
-            image.sd_extendedData = [metadata.title dataUsingEncoding:NSUTF8StringEncoding];
+            // The original metadata contains image data and is large, we pick the metadata info only to avoid double cache of image
+            LPLinkMetadata *metadata = [self.class strippedMetadata:url.sd_linkMetadata];
+            // Save the metadata to extended data
+            NSData *extendedData = [NSKeyedArchiver archivedDataWithRootObject:metadata requiringSecureCoding:YES error:nil];
+            image.sd_extendedData = extendedData;
         }
         if (completedBlock) {
             dispatch_main_async_safe(^{
@@ -220,6 +226,17 @@ - (BOOL)shouldBlockFailedURLWithURL:(NSURL *)url error:(NSError *)error {
     return shouldBlockFailedURL;
 }
 
+#pragma mark - Util
++ (LPLinkMetadata *)strippedMetadata:(LPLinkMetadata *)originalMetadata {
+    NSCParameterAssert(originalMetadata);
+    LPLinkMetadata *metadata = [LPLinkMetadata new];
+    metadata.URL = originalMetadata.URL;
+    metadata.originalURL = originalMetadata.originalURL;
+    metadata.title = originalMetadata.title;
+    metadata.remoteVideoURL = originalMetadata.remoteVideoURL;
+    return metadata;
+}
+
 #pragma mark - KVO
 
 - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context