third_party/WebKit/Source/core/html/imports/HTMLImportsController.cpp

/*
 * Copyright (C) 2013 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions are
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 * in the documentation and/or other materials provided with the
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#include "core/html/imports/HTMLImportsController.h"

#include "core/dom/Document.h"
#include "core/fetch/ResourceFetcher.h"
#include "core/frame/LocalFrame.h"
#include "core/frame/UseCounter.h"
#include "core/html/imports/HTMLImportChild.h"
#include "core/html/imports/HTMLImportChildClient.h"
#include "core/html/imports/HTMLImportLoader.h"
#include "core/html/imports/HTMLImportTreeRoot.h"

namespace blink {

HTMLImportsController::HTMLImportsController(Document& master)
    : m_root(HTMLImportTreeRoot::create(&master)) {
  UseCounter::count(master, UseCounter::HTMLImports);
}

void HTMLImportsController::dispose() {
  if (m_root) {
    m_root->dispose();
    m_root.clear();
  }

  for (size_t i = 0; i < m_loaders.size(); ++i)
    m_loaders[i]->dispose();
  m_loaders.clear();
}

static bool makesCycle(HTMLImport* parent, const KURL& url) {
  for (HTMLImport* ancestor = parent; ancestor; ancestor = ancestor->parent()) {
    if (!ancestor->isRoot() &&
        equalIgnoringFragmentIdentifier(toHTMLImportChild(parent)->url(), url))
      return true;
  }

  return false;
}

HTMLImportChild* HTMLImportsController::createChild(
    const KURL& url,
    HTMLImportLoader* loader,
    HTMLImport* parent,
    HTMLImportChildClient* client) {
  HTMLImport::SyncMode mode = client->isSync() && !makesCycle(parent, url)
                                  ? HTMLImport::Sync
                                  : HTMLImport::Async;
  if (mode == HTMLImport::Async)
    UseCounter::count(root()->document(),
                      UseCounter::HTMLImportsAsyncAttribute);

  HTMLImportChild* child = new HTMLImportChild(url, loader, mode);
  child->setClient(client);
  parent->appendImport(child);
  loader->addImport(child);
  return root()->add(child);
}

HTMLImportChild* HTMLImportsController::load(HTMLImport* parent,
                                             HTMLImportChildClient* client,
                                             FetchRequest request) {
  DCHECK(!request.url().isEmpty());
  DCHECK(request.url().isValid());
  DCHECK(parent == root() ||
         toHTMLImportChild(parent)->loader()->isFirstImport(
             toHTMLImportChild(parent)));

  if (HTMLImportChild* childToShareWith = root()->find(request.url())) {
    HTMLImportLoader* loader = childToShareWith->loader();
    DCHECK(loader);
    HTMLImportChild* child = createChild(request.url(), loader, parent, client);
    child->didShareLoader();
    return child;
  }

  request.setCrossOriginAccessControl(master()->getSecurityOrigin(),
                                      CrossOriginAttributeAnonymous);
  RawResource* resource =
      RawResource::fetchImport(request, parent->document()->fetcher());
  if (!resource)
    return nullptr;

  HTMLImportLoader* loader = createLoader();
  HTMLImportChild* child = createChild(request.url(), loader, parent, client);
  // We set resource after the import tree is built since
  // Resource::addClient() immediately calls back to feed the bytes when the
  // resource is cached.
  loader->startLoading(resource);
  child->didStartLoading();
  return child;
}

Document* HTMLImportsController::master() const {
  return root() ? root()->document() : nullptr;
}

bool HTMLImportsController::shouldBlockScriptExecution(
    const Document& document) const {
  DCHECK_EQ(document.importsController(), this);
  if (HTMLImportLoader* loader = loaderFor(document))
    return loader->shouldBlockScriptExecution();
  return root()->state().shouldBlockScriptExecution();
}

HTMLImportLoader* HTMLImportsController::createLoader() {
  m_loaders.append(HTMLImportLoader::create(this));
  return m_loaders.last().get();
}

HTMLImportLoader* HTMLImportsController::loaderFor(
    const Document& document) const {
  for (size_t i = 0; i < m_loaders.size(); ++i) {
    if (m_loaders[i]->document() == &document)
      return m_loaders[i].get();
  }

  return nullptr;
}

DEFINE_TRACE(HTMLImportsController) {
  visitor->trace(m_root);
  visitor->trace(m_loaders);
}

DEFINE_TRACE_WRAPPERS(HTMLImportsController) {
  visitor->traceWrappers(master());
}

}  // namespace blink