feat: Respond to top-level resource updates

Author: davidjohnoliver

src/SourceGenerators/Uno.UI.SourceGenerators/XamlGenerator/XamlCodeGeneration.cs

@@ -52,7 +52,8 @@ internal partial class XamlCodeGeneration
 		private readonly string _projectDirectory;
 		private readonly string _projectFullPath;
 		private readonly bool _outputSourceComments = true;
-		private readonly bool _xamlResourcesTrimming;		private readonly RoslynMetadataHelper _metadataHelper;
+		private readonly bool _xamlResourcesTrimming;
+		private readonly RoslynMetadataHelper _metadataHelper;
 
 		/// <summary>
 		/// If set, code generated from XAML will be annotated with the source method and line # in XamlFileGenerator, for easier debugging.
@@ -408,7 +409,7 @@ IEnumerable<Exception> Flatten(Exception ex)
 
 					return Location.Create(
 						xamlFile.Path,
-						xamlText.Lines.ElementAtOrDefault(xamlParsingException.LineNumber.Value-1).Span,
+						xamlText.Lines.ElementAtOrDefault(xamlParsingException.LineNumber.Value - 1).Span,
 						new LinePositionSpan(linePosition, linePosition)
 					);
 				}
@@ -439,7 +440,7 @@ private void BuildAmbientResources(XamlFileDefinition[] files, XamlGlobalStaticR
 						from module in sym.Modules
 						from reference in module.ReferencedAssemblies
 
-						// Only consider assemblies that reference Uno.UI
+							// Only consider assemblies that reference Uno.UI
 						where reference.Name == "Uno.UI" || sym.Name == "Uno.UI"
 
 						// Don't consider Uno.UI.Fluent assemblies, as they manage their own initialization
@@ -556,7 +557,8 @@ private string[] GetResourceKeys(CancellationToken ct)
 				resourceKeys = _resourceFiles
 					.AsParallel()
 					.WithCancellation(ct)
-					.SelectMany(file => {
+					.SelectMany(file =>
+					{
 						this.Log().Info("Parse resource file : " + file);
 
 						//load document
@@ -716,7 +718,7 @@ private string GenerateGlobalResources(IEnumerable<XamlFileDefinition> files, Xa
 						{
 							writer.AppendLineInvariant("_dictionariesRegistered = true;");
 
-							if(!IsUnoAssembly && !IsUnoFluentAssembly)
+							if (!IsUnoAssembly && !IsUnoFluentAssembly)
 							{
 								// For third-party libraries, expose all files using standard uri
 								foreach (var file in files.Where(IsResourceDictionary))
@@ -738,7 +740,7 @@ private string GenerateGlobalResources(IEnumerable<XamlFileDefinition> files, Xa
 							void RegisterForFile(string baseFilePath, string url)
 							{
 								var file = files.FirstOrDefault(f =>
-									f.FilePath.Substring(_projectDirectory.Length+1).Equals(baseFilePath, StringComparison.OrdinalIgnoreCase));
+									f.FilePath.Substring(_projectDirectory.Length + 1).Equals(baseFilePath, StringComparison.OrdinalIgnoreCase));
 
 								if (file != null)
 								{
@@ -766,10 +768,12 @@ void RegisterForXamlFile(XamlFileDefinition file, string url)
 						foreach (var file in files.Where(IsResourceDictionary))
 						{
 							// We leave context null because local resources should be found through Application.Resources
-							writer.AppendLineInvariant("global::Uno.UI.ResourceResolver.RegisterResourceDictionaryBySource(uri: \"{0}{1}\", context: null, dictionary: () => {2}_ResourceDictionary);",
+							writer.AppendLineInvariant("global::Uno.UI.ResourceResolver.RegisterResourceDictionaryBySource(uri: \"{0}{1}\", context: null, dictionary: () => {2}_ResourceDictionary, {3});",
 								XamlFilePathHelper.LocalResourcePrefix,
 								map.GetSourceLink(file),
-								file.UniqueID
+								file.UniqueID,
+								// Make ResourceDictionary retrievable by Hot Reload
+								_isDebug ? $"\"{file.FilePath.Replace("\\", "/")}\"" : "null"
 							);
 							// Local resources can also be found through the ms-appx:/// prefix
 							writer.AppendLineInvariant("global::Uno.UI.ResourceResolver.RegisterResourceDictionaryBySource(uri: \"{0}{1}\", context: null, dictionary: () => {2}_ResourceDictionary);",
@@ -789,7 +793,7 @@ void RegisterForXamlFile(XamlFileDefinition file, string url)
 
 					// Generate all the partial methods, even if they don't exist. That avoids
 					// having to sync the generation of the files with this global table.
-					foreach (var file in files.Select(f=>f.UniqueID).Distinct())
+					foreach (var file in files.Select(f => f.UniqueID).Distinct())
 					{
 						writer.AppendLineInvariant("static partial void RegisterDefaultStyles_{0}();", file);
 					}

src/Uno.UI.RemoteControl/HotReload/ClientHotReloadProcessor.cs

@@ -96,6 +96,13 @@ private async Task ReloadFile(FileReload fileReload)
                                 break;
                         }
                     }
+
+					if (ResourceResolver.RetrieveDictionaryForFilePath(uri.AbsolutePath) is { } targetDictionary)
+					{
+						var replacementDictionary = (ResourceDictionary)XamlReader.Load(fileReload.Content);
+						targetDictionary.CopyFrom(replacementDictionary);
+						Application.Current.UpdateResourceBindingsForHotReload();
+					}
                 }
                 catch (Exception e)
                 {

src/Uno.UI/UI/Xaml/Application.cs

@@ -322,6 +322,8 @@ private void SetRequestedTheme(ApplicationTheme requestedTheme)
 			}
 		}
 
+		internal void UpdateResourceBindingsForHotReload() => OnRequestedThemeChanged();
+
 		private void OnRequestedThemeChanged()
 		{
 			if (GetTreeRoot() is { } root)

src/Uno.UI/UI/Xaml/ResourceDictionary.cs

@@ -417,7 +417,7 @@ private bool ContainsKeyThemeMerged(in ResourceKey resourceKey, in ResourceKey a
 		/// <summary>
 		/// Copy another dictionary's contents, this is used when setting the <see cref="Source"/> property
 		/// </summary>
-		private void CopyFrom(ResourceDictionary source)
+		internal void CopyFrom(ResourceDictionary source)
 		{
 			_values.Clear();
 			_mergedDictionaries.Clear();

src/Uno.UI/UI/Xaml/ResourceResolver.cs

@@ -30,6 +30,10 @@ public static class ResourceResolver
 
 		private static readonly Dictionary<string, Func<ResourceDictionary>> _registeredDictionariesByUri = new Dictionary<string, Func<ResourceDictionary>>(StringComparer.InvariantCultureIgnoreCase);
 		private static readonly Dictionary<string, ResourceDictionary> _registeredDictionariesByAssembly = new Dictionary<string, ResourceDictionary>();
+		/// <summary>
+		/// This is used by hot reload (since converting the file path to a Source is impractical at runtime).
+		/// </summary>
+		private static readonly Dictionary<string, Func<ResourceDictionary>> _registeredDictionariesByFilepath = new Dictionary<string, Func<ResourceDictionary>>(StringComparer.InvariantCultureIgnoreCase);
 
 		private static int _assemblyRef = -1;
 
@@ -244,7 +248,7 @@ private static bool TryStaticRetrieval(in SpecializedResourceDictionary.Resource
 
 			while (sourcesEnumerator.MoveNext())
 			{
-				
+
 				var source = sourcesEnumerator.Current;
 
 				var dictionary = (source.Target as FrameworkElement)?.Resources
@@ -375,12 +379,15 @@ internal static void PopScope()
 		/// </summary>
 		internal static IDisposable WriteInitiateGlobalStaticResourcesEventActivity() => _trace.WriteEventActivity(TraceProvider.InitGenericXamlStart, TraceProvider.InitGenericXamlStop);
 
+		[EditorBrowsable(EditorBrowsableState.Never)]
+		public static void RegisterResourceDictionaryBySource(string uri, XamlParseContext context, Func<ResourceDictionary> dictionary)
+			=> RegisterResourceDictionaryBySource(uri, context, dictionary, null);
 		/// <summary>
 		/// Register a dictionary for a given source, this is used for retrieval when setting the Source property in code-behind or to an
 		/// external resource.
 		/// </summary>
 		[EditorBrowsable(EditorBrowsableState.Never)]
-		public static void RegisterResourceDictionaryBySource(string uri, XamlParseContext context, Func<ResourceDictionary> dictionary)
+		public static void RegisterResourceDictionaryBySource(string uri, XamlParseContext context, Func<ResourceDictionary> dictionary, string filePath)
 		{
 			_registeredDictionariesByUri[uri] = dictionary;
 
@@ -392,6 +399,11 @@ public static void RegisterResourceDictionaryBySource(string uri, XamlParseConte
 				_assemblyRef++; // We don't actually use this key, we just need it to be unique
 				assemblyDict[_assemblyRef] = initializer;
 			}
+
+			if (filePath != null)
+			{
+				_registeredDictionariesByFilepath[filePath] = dictionary;
+			}
 		}
 
 		/// <summary>
@@ -433,6 +445,16 @@ public static ResourceDictionary RetrieveDictionaryForSource(string source, stri
 			throw new InvalidOperationException($"Cannot locate resource from '{source}'");
 		}
 
+		internal static ResourceDictionary RetrieveDictionaryForFilePath(string filePath)
+		{
+			if (_registeredDictionariesByFilepath.TryGetValue(filePath, out var func))
+			{
+				return func();
+			}
+
+			return null;
+		}
+
 		/// <summary>
 		/// Retrieves a resource for a {CustomResource} markup, with the <see cref="CustomXamlResourceLoader"/> currently set.
 		/// </summary>