Save and share all items in album.

Signal/src/ViewControllers/ConversationView/ConversationViewItem.m

@@ -9,7 +9,6 @@
 #import "OWSMessageHeaderView.h"
 #import "OWSSystemMessageCell.h"
 #import "Signal-Swift.h"
-#import <AssetsLibrary/AssetsLibrary.h>
 #import <SignalMessaging/OWSUnreadIndicator.h>
 #import <SignalServiceKit/NSData+Image.h>
 #import <SignalServiceKit/NSString+SSK.h>
@@ -1020,39 +1019,57 @@ NSString *NSStringForOWSMessageCellType(OWSMessageCellType cellType)
             break;
         }
         case OWSMessageCellType_MediaAlbum: {
-            // TODO: Use PHPhotoLibrary.
-            ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
-            for (ConversationMediaAlbumItem *mediaAlbumItem in self.mediaAlbumItems) {
-                if (!mediaAlbumItem.attachmentStream) {
-                    continue;
-                }
-                if (!mediaAlbumItem.attachmentStream.isValidVisualMedia) {
-                    continue;
-                }
-                if (mediaAlbumItem.attachmentStream.isImage || mediaAlbumItem.attachmentStream.isAnimated) {
-                    NSData *data = [NSData dataWithContentsOfURL:[mediaAlbumItem.attachmentStream originalMediaURL]];
-                    if (!data) {
-                        OWSFailDebug(@"Could not load image data");
-                        continue;
-                    }
-                    [library writeImageDataToSavedPhotosAlbum:data
-                                                     metadata:nil
-                                              completionBlock:^(NSURL *assetURL, NSError *error) {
-                                                  if (error) {
-                                                      OWSLogWarn(@"Error saving image to photo album: %@", error);
-                                                  }
-                                              }];
-                }
-                if (mediaAlbumItem.attachmentStream.isVideo) {
-                    if (UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(
-                            mediaAlbumItem.attachmentStream.originalFilePath)) {
-                        UISaveVideoAtPathToSavedPhotosAlbum(
-                            mediaAlbumItem.attachmentStream.originalFilePath, self, nil, nil);
-                    }
+            [self saveMediaAlbumItems];
+            break;
+        }
+    }
+}
+
+- (void)saveMediaAlbumItems
+{
+    // We need to do these writes serially to avoid "write busy" errors
+    // from too many concurrent asset saves.
+    [self saveMediaAlbumItems:[self.mediaAlbumItems mutableCopy]];
+}
+
+- (void)saveMediaAlbumItems:(NSMutableArray<ConversationMediaAlbumItem *> *)mediaAlbumItems
+{
+    if (mediaAlbumItems.count < 1) {
+        return;
+    }
+    ConversationMediaAlbumItem *mediaAlbumItem = mediaAlbumItems.firstObject;
+    [mediaAlbumItems removeObjectAtIndex:0];
+
+    if (!mediaAlbumItem.attachmentStream || !mediaAlbumItem.attachmentStream.isValidVisualMedia) {
+        // Skip this item.
+    } else if (mediaAlbumItem.attachmentStream.isImage || mediaAlbumItem.attachmentStream.isAnimated) {
+        [[PHPhotoLibrary sharedPhotoLibrary]
+            performChanges:^{
+                [PHAssetChangeRequest
+                    creationRequestForAssetFromImageAtFileURL:mediaAlbumItem.attachmentStream.originalMediaURL];
+            }
+            completionHandler:^(BOOL success, NSError *error) {
+                if (error || !success) {
+                    OWSFailDebug(@"Image save failed: %@", error);
                 }
+                [self saveMediaAlbumItems:mediaAlbumItems];
+            }];
+        return;
+    } else if (mediaAlbumItem.attachmentStream.isVideo) {
+        [[PHPhotoLibrary sharedPhotoLibrary]
+            performChanges:^{
+                [PHAssetChangeRequest
+                    creationRequestForAssetFromVideoAtFileURL:mediaAlbumItem.attachmentStream.originalMediaURL];
             }
-        }
+            completionHandler:^(BOOL success, NSError *error) {
+                if (error || !success) {
+                    OWSFailDebug(@"Video save failed: %@", error);
+                }
+                [self saveMediaAlbumItems:mediaAlbumItems];
+            }];
+        return;
     }
+    return [self saveMediaAlbumItems:mediaAlbumItems];
 }
 
 - (void)deleteAction