HTML Imports: No more BlockingDocumentCreation.

Source/core/html/imports/HTMLImportChild.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 54 matching lines @@
     if (m_client)
         m_client->importChildWasDestroyed(this);
 
     m_master.guardDeref();
 }
 
 void HTMLImportChild::wasAlreadyLoaded()
 {
     ASSERT(!m_loader);
     ASSERT(m_client);
+    ensureLoader();
     stateWillChange();
 }
 
 void HTMLImportChild::startLoading(const ResourcePtr<RawResource>& resource)
 {
     ASSERT(!this->resource());
     ASSERT(!m_loader);
 
-    if (isSync()) {
-        ASSERT(!m_customElementMicrotaskStep);
-        m_customElementMicrotaskStep = CustomElement::didCreateImport(this);
-    }
-
     setResource(resource);
 
-    // If the node is "document blocked", it cannot create HTMLImportLoader
-    // even if there is no sharable one found, as there is possibility that
-    // preceding imports load the sharable imports.
-    // In that case preceding one should win because it comes first in the tree order.
-    // See also didUnblockFromCreatingDocument().
-    if (state().shouldBlockDocumentCreation())
-        return;
-
     ensureLoader();
 }
 
 void HTMLImportChild::didFinish()
 {
     if (m_client)
         m_client->didFinish();
 
     if (m_customElementMicrotaskStep) {
         m_customElementMicrotaskStep->importDidFinish();
@@ skipping 19 matching lines @@
     if (parent())
         parent()->removeChild(this);
     if (m_loader) {
         m_loader->removeImport(this);
         m_loader = 0;
     }
 }
 
 Document* HTMLImportChild::document() const
 {
-    return (m_loader && m_loader->isOwnedBy(this)) ? m_loader->document() : 0;
+    return m_loader ? m_loader->document() : 0;
 }
 
 void HTMLImportChild::stateWillChange()
 {
     toHTMLImportsController(root())->scheduleRecalcState();
 }
 
 void HTMLImportChild::stateDidChange()
 {
     HTMLImport::stateDidChange();
 
-    // Once all preceding imports are loaded,
-    // HTMLImportChild can decide whether it should load the import by itself
-    // or it can share existing one.
-    if (!state().shouldBlockDocumentCreation())
-        ensureLoader();
+    ensureLoader();
     if (state().isReady())
         didFinish();
 }
 
 void HTMLImportChild::ensureLoader()
 {
     if (m_loader)
         return;
 
     if (HTMLImportChild* found = toHTMLImportsController(root())->findLinkFor(m_url, this))
         shareLoader(found);
     else
         createLoader();
+
+    if (isSync() && !isDone()) {
+        ASSERT(!m_customElementMicrotaskStep);
+        m_customElementMicrotaskStep = CustomElement::didCreateImport(this);

[dominicc (has gone to gerrit), 2014/04/18 00:56:26]

I like the simplicity of this. Its a bit wasteful to create the microtask queue
for an import that doesn't have Custom Elements, but I suppose many imports will
have Custom Elements in practice?

[Hajime Morrita, 2014/04/18 01:48:33]

That's my thinking, and making it lazy complicates the lifecycle management and
dependency.

+    }
 }
 
 void HTMLImportChild::createLoader()
 {
-    ASSERT(!state().shouldBlockDocumentCreation());
     ASSERT(!m_loader);
     m_loader = toHTMLImportsController(root())->createLoader();
     m_loader->addImport(this);
     m_loader->startLoading(resource());
 }
 
 void HTMLImportChild::shareLoader(HTMLImportChild* loader)
 {
     ASSERT(!m_loader);
     m_loader = loader->m_loader;
     m_loader->addImport(this);
     stateWillChange();
 }
 
 bool HTMLImportChild::isDone() const
 {
     return m_loader && m_loader->isDone();
 }
 
-bool HTMLImportChild::hasLoader() const
-{
-    return m_loader;
-}
-
-bool HTMLImportChild::ownsLoader() const
-{
-    return m_loader && m_loader->isOwnedBy(this);
-}
-
 bool HTMLImportChild::loaderHasError() const
 {
     return m_loader && m_loader->hasError();
 }
 
 
 void HTMLImportChild::setClient(HTMLImportChildClient* client)
 {
     ASSERT(client);
     ASSERT(!m_client);
@@ skipping 11 matching lines @@
 {
     if (!m_client)
         return 0;
     return m_client->link();
 }
 
 #if !defined(NDEBUG)
 void HTMLImportChild::showThis()
 {
     HTMLImport::showThis();
-    fprintf(stderr, " loader=%p own=%s async=%s url=%s",
+    fprintf(stderr, " loader=%p sync=%s url=%s",
         m_loader,
-        hasLoader() && ownsLoader() ? "Y" : "N",
         isSync() ? "Y" : "N",
         url().string().utf8().data());
 }
 #endif
 
 } // namespace WebCore