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// Copyright 2014 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "cobalt/dom/html_link_element.h"
#include <algorithm>
#include <string>
#include <vector>
#include "base/bind.h"
#include "base/debug/trace_event.h"
#include "cobalt/cssom/css_parser.h"
#include "cobalt/cssom/css_style_sheet.h"
#include "cobalt/dom/csp_delegate.h"
#include "cobalt/dom/document.h"
#include "cobalt/dom/html_element_context.h"
#include "cobalt/dom/window.h"
#include "googleurl/src/gurl.h"
#include "nb/memory_scope.h"
namespace cobalt {
namespace dom {
namespace {
CspDelegate::ResourceType GetCspResourceTypeForRel(const std::string& rel) {
if (rel == "stylesheet") {
return CspDelegate::kStyle;
} else if (rel == "splashscreen") {
return CspDelegate::kLocation;
} else {
NOTIMPLEMENTED();
return CspDelegate::kImage;
}
}
bool IsRelContentCriticalResource(const std::string& rel) {
return rel == "stylesheet";
}
} // namespace
// static
const char HTMLLinkElement::kTagName[] = "link";
// static
const std::vector<std::string> HTMLLinkElement::kSupportedRelValues = {
"stylesheet", "splashscreen"};
void HTMLLinkElement::OnInsertedIntoDocument() {
HTMLElement::OnInsertedIntoDocument();
if (std::find(kSupportedRelValues.begin(), kSupportedRelValues.end(),
rel()) != kSupportedRelValues.end()) {
Obtain();
} else {
LOG(WARNING) << "<link> has unsupported rel value: " << rel() << ".";
}
}
void HTMLLinkElement::OnRemovedFromDocument() {
HTMLElement::OnRemovedFromDocument();
if (style_sheet_) {
Document* document = node_document();
if (document) {
document->OnStyleSheetsModified();
}
}
}
void HTMLLinkElement::ResolveAndSetAbsoluteURL() {
// Resolve the URL given by the href attribute, relative to the element.
const GURL& base_url = node_document()->url_as_gurl();
absolute_url_ = base_url.Resolve(href());
LOG_IF(WARNING, !absolute_url_.is_valid())
<< href() << " cannot be resolved based on " << base_url << ".";
}
// Algorithm for Obtain:
// https://www.w3.org/TR/html5/document-metadata.html#concept-link-obtain
void HTMLLinkElement::Obtain() {
TRACK_MEMORY_SCOPE("DOM");
TRACE_EVENT0("cobalt::dom", "HTMLLinkElement::Obtain()");
// Custom, not in any spec.
DCHECK(thread_checker_.CalledOnValidThread());
Document* document = node_document();
// If the document has no browsing context, do not obtain, parse or apply the
// resource.
if (!document->html_element_context()) {
return;
}
DCHECK(MessageLoop::current());
DCHECK(!loader_);
// 1. If the href attribute's value is the empty string, then abort these
// steps.
if (href().empty()) {
return;
}
// 2. Resolve the URL given by the href attribute, relative to the element.
ResolveAndSetAbsoluteURL();
// 3. If the previous step fails, then abort these steps.
if (!absolute_url_.is_valid()) {
return;
}
// 4. Do a potentially CORS-enabled fetch of the resulting absolute URL, with
// the mode being the current state of the element's crossorigin content
// attribute, the origin being the origin of the link element's Document, and
// the default origin behaviour set to taint.
csp::SecurityCallback csp_callback = base::Bind(
&CspDelegate::CanLoad, base::Unretained(document->csp_delegate()),
GetCspResourceTypeForRel(rel()));
fetched_last_url_origin_ = loader::Origin();
if (IsRelContentCriticalResource(rel())) {
// The element must delay the load event of the element's document until all
// the attempts to obtain the resource and its critical subresources are
// complete.
document->IncreaseLoadingCounter();
}
loader_ = make_scoped_ptr(new loader::Loader(
base::Bind(
&loader::FetcherFactory::CreateSecureFetcher,
base::Unretained(document->html_element_context()->fetcher_factory()),
absolute_url_, csp_callback),
scoped_ptr<loader::Decoder>(new loader::TextDecoder(
base::Bind(&HTMLLinkElement::OnLoadingDone, base::Unretained(this)))),
base::Bind(&HTMLLinkElement::OnLoadingError, base::Unretained(this))));
}
void HTMLLinkElement::OnLoadingDone(const std::string& content,
const loader::Origin& last_url_origin) {
TRACK_MEMORY_SCOPE("DOM");
DCHECK(thread_checker_.CalledOnValidThread());
TRACE_EVENT0("cobalt::dom", "HTMLLinkElement::OnLoadingDone()");
// Get resource's final destination url from loader.
fetched_last_url_origin_ = last_url_origin;
Document* document = node_document();
if (rel() == "stylesheet") {
OnStylesheetLoaded(document, content);
} else if (rel() == "splashscreen") {
OnSplashscreenLoaded(document, content);
} else {
NOTIMPLEMENTED();
return;
}
// Once the attempts to obtain the resource and its critical subresources
// are complete, the user agent must, if the loads were successful, queue a
// task to fire a simple event named load at the link element, or, if the
// resource or one of its critical subresources failed to completely load
// for any reason (e.g. DNS error, HTTP 404 response, a connection being
// prematurely closed, unsupported Content-Type), queue a task to fire a
// simple event named error at the link element.
PostToDispatchEvent(FROM_HERE, base::Tokens::load());
if (IsRelContentCriticalResource(rel())) {
// The element must delay the load event of the element's document until all
// the attempts to obtain the resource and its critical subresources are
// complete.
document->DecreaseLoadingCounterAndMaybeDispatchLoadEvent();
}
MessageLoop::current()->PostTask(
FROM_HERE, base::Bind(&HTMLLinkElement::ReleaseLoader, this));
}
void HTMLLinkElement::OnLoadingError(const std::string& error) {
DCHECK(thread_checker_.CalledOnValidThread());
TRACE_EVENT0("cobalt::dom", "HTMLLinkElement::OnLoadingError()");
LOG(ERROR) << error;
// Once the attempts to obtain the resource and its critical subresources are
// complete, the user agent must, if the loads were successful, queue a task
// to fire a simple event named load at the link element, or, if the resource
// or one of its critical subresources failed to completely load for any
// reason (e.g. DNS error, HTTP 404 response, a connection being prematurely
// closed, unsupported Content-Type), queue a task to fire a simple event
// named error at the link element.
PostToDispatchEvent(FROM_HERE, base::Tokens::error());
if (IsRelContentCriticalResource(rel())) {
// The element must delay the load event of the element's document until all
// the attempts to obtain the resource and its critical subresources are
// complete.
node_document()->DecreaseLoadingCounterAndMaybeDispatchLoadEvent();
}
MessageLoop::current()->PostTask(
FROM_HERE, base::Bind(&HTMLLinkElement::ReleaseLoader, this));
}
void HTMLLinkElement::OnSplashscreenLoaded(Document* document,
const std::string& content) {
scoped_refptr<Window> window = document->window();
window->CacheSplashScreen(content);
}
void HTMLLinkElement::OnStylesheetLoaded(Document* document,
const std::string& content) {
scoped_refptr<cssom::CSSStyleSheet> css_style_sheet =
document->html_element_context()->css_parser()->ParseStyleSheet(
content, base::SourceLocation(href(), 1, 1));
css_style_sheet->SetLocationUrl(absolute_url_);
// If not loading from network-fetched resources or fetched resource is same
// origin as the document, set origin-clean flag to true.
if (!loader_ || document->url_as_gurl().SchemeIsFile() ||
(fetched_last_url_origin_ == document->location()->OriginObject())) {
css_style_sheet->SetOriginClean(true);
}
style_sheet_ = css_style_sheet;
document->OnStyleSheetsModified();
}
void HTMLLinkElement::ReleaseLoader() {
DCHECK(thread_checker_.CalledOnValidThread());
DCHECK(loader_);
loader_.reset();
}
void HTMLLinkElement::CollectStyleSheet(
cssom::StyleSheetVector* style_sheets) const {
if (style_sheet_) {
style_sheets->push_back(style_sheet_);
}
}
} // namespace dom
} // namespace cobalt