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Clean up + reintroduced some notes, that will maybe be usefull when website rendering is ready

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Signed-off-by: Bjarke Berg <mail@bergmania.dk>
This commit is contained in:
Bjarke Berg
2020-09-09 12:46:23 +02:00
parent 1923cf013c
commit 06713ea03a
4 changed files with 67 additions and 80 deletions
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66
src/Umbraco.ModelsBuilder.Embedded/PureLiveModelFactory.cs
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@@ -152,6 +152,62 @@ namespace Umbraco.ModelsBuilder.Embedded
#endregion
#region Compilation
// deadlock note
//
// when RazorBuildProvider_CodeGenerationStarted runs, the thread has Monitor.Enter-ed the BuildManager
// singleton instance, through a call to CompilationLock.GetLock in BuildManager.GetVPathBuildResultInternal,
// and now wants to lock _locker.
// when EnsureModels runs, the thread locks _locker and then wants BuildManager to compile, which in turns
// requires that the BuildManager can Monitor.Enter-ed itself.
// so:
//
// T1 - needs to ensure models, locks _locker
// T2 - needs to compile a view, locks BuildManager
// hits RazorBuildProvider_CodeGenerationStarted
// wants to lock _locker, wait
// T1 - needs to compile models, using BuildManager
// wants to lock itself, wait
// <deadlock>
//
// until ASP.NET kills the long-running request (thread abort)
//
// problem is, we *want* to suspend views compilation while the models assembly is being changed else we
// end up with views compiled and cached with the old assembly, while models come from the new assembly,
// which gives more YSOD. so we *have* to lock _locker in RazorBuildProvider_CodeGenerationStarted.
//
// one "easy" solution consists in locking the BuildManager *before* _locker in EnsureModels, thus ensuring
// we always lock in the same order, and getting rid of deadlocks - but that requires having access to the
// current BuildManager instance, which is BuildManager.TheBuildManager, which is an internal property.
//
// well, that's what we are doing in this class' TheBuildManager property, using reflection.
// private void RazorBuildProvider_CodeGenerationStarted(object sender, EventArgs e)
// {
// try
// {
// _locker.EnterReadLock();
//
// // just be safe - can happen if the first view is not an Umbraco view,
// // or if something went wrong and we don't have an assembly at all
// if (_modelsAssembly == null) return;
//
// if (_debugLevel > 0)
// _logger.Debug<PureLiveModelFactory>("RazorBuildProvider.CodeGenerationStarted");
// if (!(sender is RazorBuildProvider provider)) return;
//
// // add the assembly, and add a dependency to a text file that will change on each
// // compilation as in some environments (could not figure which/why) the BuildManager
// // would not re-compile the views when the models assembly is rebuilt.
// provider.AssemblyBuilder.AddAssemblyReference(_modelsAssembly);
// provider.AddVirtualPathDependency(ProjVirt);
// }
// finally
// {
// if (_locker.IsReadLockHeld)
// _locker.ExitReadLock();
// }
// }
// tells the factory that it should build a new generation of models
private void ResetModels()
@@ -278,14 +334,14 @@ namespace Umbraco.ModelsBuilder.Embedded
private Assembly ReloadAssembly(string pathToAssembly)
{
// If there's a current AssemblyLoadContext, unload it before creating a new one.
// If there's a current AssemblyLoadContext, unload it before creating a new one.
if(!(_currentAssemblyLoadContext is null))
{
_currentAssemblyLoadContext.Unload();
GC.Collect();
GC.WaitForPendingFinalizers();
}
// We must create a new assembly load context
// as long as theres a reference to the assembly load context we can't delete the assembly it loaded
_currentAssemblyLoadContext = new UmbracoAssemblyLoadContext();
@@ -352,7 +408,7 @@ namespace Umbraco.ModelsBuilder.Embedded
if (File.Exists(dllPath) && !File.Exists(dllPath + ".delete"))
{
assembly = ReloadAssembly(dllPath);
var attr = assembly.GetCustomAttribute<ModelsBuilderAssemblyAttribute>();
if (attr != null && attr.PureLive && attr.SourceHash == currentHash)
{
@@ -461,13 +517,13 @@ namespace Umbraco.ModelsBuilder.Embedded
{
File.Delete(file.FullName);
}
catch(UnauthorizedAccessException e)
catch(UnauthorizedAccessException)
{
// The file is in use, we'll try again next time...
// This shouldn't happen anymore.
}
}
}
}