Allow async onCreatePublication callbacks (#673)

Author: smoores-dev

CHANGELOG.md

@@ -13,6 +13,12 @@ All notable changes to this project will be documented in this file. Take a look
     * This callback is called before executing any navigation action.
     * Useful for hiding UI elements when the user navigates, or implementing analytics.
 
+### Changed
+
+#### Streamer
+
+* Support for asynchronous callbacks with `onCreatePublication` (contributed by [@smoores-dev](https://github.com/readium/swift-toolkit/pull/673)).
+
 
 ## [3.5.0]
 

Sources/Shared/Publication/Publication.swift

@@ -169,7 +169,7 @@ public class Publication: Closeable, Loggable {
             _ manifest: inout Manifest,
             _ container: inout Container,
             _ services: inout PublicationServicesBuilder
-        ) -> Void
+        ) async -> Void
 
         private var manifest: Manifest
         private var container: Container
@@ -185,12 +185,12 @@ public class Publication: Closeable, Loggable {
             self.servicesBuilder = servicesBuilder
         }
 
-        public mutating func apply(_ transform: Transform?) {
+        public mutating func apply(_ transform: Transform?) async {
             guard let transform = transform else {
                 return
             }
 
-            transform(&manifest, &container, &servicesBuilder)
+            await transform(&manifest, &container, &servicesBuilder)
         }
 
         /// Builds the `Publication` from its parts.

Sources/Streamer/PublicationOpener.swift

@@ -93,7 +93,7 @@ public class PublicationOpener {
         switch await parser.parse(asset: asset, warnings: warnings) {
         case var .success(builder):
             for transform in builderTransforms {
-                builder.apply(transform)
+                await builder.apply(transform)
             }
             return .success(builder.build())