/// <summary>
/// Loads the specified set of resources by creating template language generators and loading
/// the content asynchronously.
/// </summary>
/// <remarks>Once LoadAsync() is completed, the manager is fully initialized. Note that the this set up supports
/// GenerateASync() being called in the generators in other threads while we are loading, and the thread-safe lazy initialization
/// is ensuring that a single thread initializes the resources.</remarks>
/// <param name="resources">Resources to load.</param>
/// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
private async Task LoadAsync(IEnumerable <Resource> resources)
{
var loadTaskMap = new Dictionary <Resource, (Task LoadTask, TemplateEngineLanguageGenerator Generator)>();
// Create one LanguageGenerator for each resource. Given that each language generator needs
// to asynchronous load its content, we trigger these loading tasks async and them wait for them all to be done.
foreach (var resource in resources)
{
// Create generator, explicitly asking to not load resources on construction so we can do it asynchronously.
var generator = new TemplateEngineLanguageGenerator(resource, _multilanguageResources);
// Capture loading task and store in temporary map.
var generatorLoadTask = generator.LoadAsync();
loadTaskMap.Add(resource, (generatorLoadTask, generator));
}
// Wait for loading to complete.
await Task.WhenAll(loadTaskMap.Select(entry => entry.Value.LoadTask)).ConfigureAwait(false);
// Build our language generator table with the fully loaded generators.
foreach (var entry in loadTaskMap)
{
LanguageGenerators[entry.Key.Id] = new Lazy <LanguageGenerator>(() => entry.Value.Generator);
}
}
/// <summary>
/// Populates the <see cref="LanguageGenerators"/> property with <see cref="Lazy{LaguageGenerator}" /> instances.
/// </summary>
/// <remarks>
/// If the resource contains exports, this method also ensure the LanguageGenerator instance is loaded and ready to use.
/// </remarks>
private void PopulateLanguageGenerators()
{
var resources = _resourceExplorer.GetResources("lg");
// Create one LanguageGenerator for each resource.
foreach (var resource in resources)
{
LanguageGenerators[resource.Id] = new Lazy <LanguageGenerator>(() =>
{
// Creates the generator when requested and loads it.
var generator = new TemplateEngineLanguageGenerator(resource, _multilanguageResources);
generator.LoadAsync().GetAwaiter().GetResult();
return(generator);
});
// Check if the file contains exports.
if (ContainsExport(resource))
{
// Force lazy creation for lg files that contain exports
// Exports need to be available globally and need to be parsed at startup
_ = LanguageGenerators[resource.Id].Value;
}
}
}
