private ViewCompilerWorkItem CreatePrecompiledWorkItem(string normalizedPath, CompiledViewDescriptor precompiledView)
{
// We have a precompiled view - but we're not sure that we can use it yet.
//
// We need to determine first if we have enough information to 'recompile' this view. If that's the case
// we'll create change tokens for all of the files.
//
// Then we'll attempt to validate if any of those files have different content than the original sources
// based on checksums.
if (precompiledView.Item == null || !PublicChecksumValidator.IsRecompilationSupported(precompiledView.Item))
{
return(new ViewCompilerWorkItem {
// If we don't have a checksum for the primary source file we can't recompile.
SupportsCompilation = false,
ExpirationTokens = Array.Empty <IChangeToken>(), // Never expire because we can't recompile.
Descriptor = precompiledView, // This will be used as-is.
});
}
var item = new ViewCompilerWorkItem {
SupportsCompilation = true,
Descriptor = precompiledView, // This might be used, if the checksums match.
// Used to validate and recompile
NormalizedPath = normalizedPath,
ExpirationTokens = GetExpirationTokens(precompiledView)
};
// We also need to create a new descriptor, because the original one doesn't have expiration tokens on
// it. These will be used by the view location cache, which is like an L1 cache for views (this class is
// the L2 cache).
item.Descriptor = new CompiledViewDescriptor()
{
ExpirationTokens = item.ExpirationTokens,
Item = precompiledView.Item,
RelativePath = precompiledView.RelativePath,
};
return(item);
}
private Task <CompiledViewDescriptor> OnCacheMiss(string normalizedPath)
{
ViewCompilerWorkItem item;
TaskCompletionSource <CompiledViewDescriptor> taskSource;
MemoryCacheEntryOptions cacheEntryOptions;
// Safe races cannot be allowed when compiling Razor pages. To ensure only one compilation request succeeds
// per file, we'll lock the creation of a cache entry. Creating the cache entry should be very quick. The
// actual work for compiling files happens outside the critical section.
lock (cacheLock) {
// Double-checked locking to handle a possible race.
if (cache.TryGetValue(normalizedPath, out Task <CompiledViewDescriptor> result))
{
return(result);
}
if (precompiledViews.TryGetValue(normalizedPath, out var precompiledView))
{
// item = CreatePrecompiledWorkItem(normalizedPath, precompiledView);
// precompiledViews.Remove(normalizedPath); // Once it is in a work item remove it.
item = CreateRuntimeCompilationWorkItem(normalizedPath, precompiledView);
}
else
{
item = CreateRuntimeCompilationWorkItem(normalizedPath, null);
}
var tokens = new List <IChangeToken>();
taskSource = new TaskCompletionSource <CompiledViewDescriptor>(creationOptions: TaskCreationOptions.RunContinuationsAsynchronously);
tokens.AddRange(item.ExpirationTokens);
if (!item.SupportsCompilation)
{
taskSource.SetResult(item.Descriptor);
}
cacheEntryOptions = new MemoryCacheEntryOptions();
foreach (var token in tokens)
{
cacheEntryOptions.ExpirationTokens.Add(token);
}
cache.Set(normalizedPath, taskSource.Task, cacheEntryOptions);
}
// Now the lock has been released so we can do more expensive processing.
if (item.SupportsCompilation)
{
Debug.Assert(taskSource is object);
if (item.Descriptor?.Item is object)
{
var itemAssemblyName = item.Descriptor.Item.Type.Assembly.GetName().Name;
// If we dont have an engine for the library
if (!projectEngines.TryGetValue(itemAssemblyName, out var engine))
{
engine = projectEngines.First().Value;
}
// If nothing changed serve that mofo
if (PublicChecksumValidator.IsItemValid(engine.FileSystem, item.Descriptor.Item))
{
Debug.Assert(item.Descriptor != null);
taskSource.SetResult(item.Descriptor);
return(taskSource.Task);
}
// Otherwise try to recompile
try {
var descriptor = CompileAndEmit(normalizedPath, engine, itemAssemblyName);
descriptor.ExpirationTokens = cacheEntryOptions.ExpirationTokens;
taskSource.SetResult(descriptor);
return(taskSource.Task);
} catch (Exception ex) {
logger.LogError(ex, "Razor blowup");
taskSource.SetException(ex);
return(taskSource.Task);
}
}
// _logger.ViewCompilerInvalidingCompiledFile(item.NormalizedPath);
var exceptions = new List <Exception>();
foreach (var engine in projectEngines)
{
var file = engine.Value.FileSystem.GetItem(normalizedPath, null);
if (file.Exists)
{
if (item.OriginalDescriptor is object)
{
if (PublicChecksumValidator.IsItemValid(engine.Value.FileSystem, item.OriginalDescriptor.Item))
{
taskSource.SetResult(item.OriginalDescriptor);
return(taskSource.Task);
}
}
try {
var descriptor = CompileAndEmit(normalizedPath, engine.Value, engine.Key);
descriptor.ExpirationTokens = cacheEntryOptions.ExpirationTokens;
taskSource.SetResult(descriptor);
return(taskSource.Task);
} catch (Exception ex) {
exceptions.Add(ex);
logger.LogError(ex, "Razor blowup");
}
}
}
if (exceptions.Count > 0)
{
taskSource.SetException(exceptions.AsEnumerable());
}
}
return(taskSource.Task);
}
private ViewCompilerWorkItem CreateRuntimeCompilationWorkItem(string normalizedPath, CompiledViewDescriptor originalDescriptor)
{
if (originalDescriptor is object)
{
if (originalDescriptor.Item == null || !PublicChecksumValidator.IsRecompilationSupported(originalDescriptor.Item))
{
return(new ViewCompilerWorkItem {
// If we don't have a checksum for the primary source file we can't recompile.
SupportsCompilation = false,
ExpirationTokens = Array.Empty <IChangeToken>(), // Never expire because we can't recompile.
Descriptor = originalDescriptor, // This will be used as-is.
});
}
var assembly = originalDescriptor.Item.Type?.Assembly.GetName().Name;
if (!string.IsNullOrEmpty(assembly) && this.projectEngines.TryGetValue(assembly, out var origEngine))
{
var projectItem = origEngine.FileSystem.GetItem(normalizedPath, fileKind: null);
if (!projectItem.Exists)
{
originalDescriptor = null; //force recompilation
}
}
}
var allTokens = new List <IChangeToken>();
var exists = false;
foreach (var engine in this.projectEngines)
{
var fileProvider = GetProviderFromRazorProjectEngine(engine.Value);
IList <IChangeToken> expirationTokens = new List <IChangeToken> {
fileProvider.Watch(normalizedPath),
};
var projectItem = engine.Value.FileSystem.GetItem(normalizedPath, fileKind: null);
if (projectItem.Exists)
{
exists = true;
var importFeature = engine.Value.ProjectFeatures.OfType <IImportProjectFeature>().ToArray();
foreach (var feature in importFeature)
{
foreach (var file in feature.GetImports(projectItem))
{
if (file.FilePath != null)
{
expirationTokens.Add(GetProviderFromRazorProjectEngine(engine.Value).Watch(file.FilePath));
}
}
}
}
allTokens.AddRange(expirationTokens);
// _logger.ViewCompilerFoundFileToCompile(normalizedPath);
}
if (originalDescriptor is object)
{
originalDescriptor.ExpirationTokens = allTokens;
}
return(new ViewCompilerWorkItem()
{
SupportsCompilation = exists,
NormalizedPath = normalizedPath,
ExpirationTokens = allTokens,
Descriptor = exists ? default : new CompiledViewDescriptor()
{
RelativePath = normalizedPath,
ExpirationTokens = allTokens
},
OriginalDescriptor = originalDescriptor
});