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/*
* Copyright 2015 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_image_element.h"
#include <string>
#include "base/debug/trace_event.h"
#include "base/message_loop.h"
#include "cobalt/base/polymorphic_downcast.h"
#include "cobalt/dom/csp_delegate.h"
#include "cobalt/dom/document.h"
#include "cobalt/dom/dom_settings.h"
#include "cobalt/dom/html_element_context.h"
#include "cobalt/script/global_environment.h"
#include "googleurl/src/gurl.h"
namespace cobalt {
namespace dom {
// static
const char HTMLImageElement::kTagName[] = "img";
HTMLImageElement::HTMLImageElement(script::EnvironmentSettings* env_settings)
: HTMLElement(base::polymorphic_downcast<DOMSettings*>(env_settings)
->window()
->document(),
base::Token(kTagName)),
prevent_garbage_collection_count_(0) {}
void HTMLImageElement::OnSetAttribute(const std::string& name,
const std::string& /* value */) {
// A user agent that obtains images immediately must synchronously update the
// image data of an img element whenever that element is created with a src
// attribute. A user agent that obtains images immediately must also
// synchronously update the image data of an img element whenever that element
// has its src or crossorigin attribute set, changed, or removed.
if (name == "src") {
UpdateImageData();
}
}
void HTMLImageElement::OnRemoveAttribute(const std::string& name) {
// A user agent that obtains images immediately must synchronously update the
// image data of an img element whenever that element is created with a src
// attribute. A user agent that obtains images immediately must also
// synchronously update the image data of an img element whenever that element
// has its src or crossorigin attribute set, changed, or removed.
if (name == "src") {
UpdateImageData();
}
}
// Algorithm for UpdateTheImageData:
// https://www.w3.org/TR/html5/embedded-content-0.html#update-the-image-data
void HTMLImageElement::UpdateImageData() {
DCHECK(MessageLoop::current());
TRACE_EVENT0("cobalt::dom", "HTMLImageElement::UpdateImageData()");
// 1. Not needed by Cobalt.
// 2. If an instance of the fetching algorithm is still running for this
// element, then abort that algorithm, discarding any pending tasks generated
// by that algorithm.
// 3. Forget the img element's current image data, if any.
if (cached_image_loaded_callback_handler_) {
cached_image_loaded_callback_handler_.reset();
node_document()->DecreaseLoadingCounter();
}
// 4. If the user agent cannot support images, or its support for images has
// been disabled, then abort these steps.
// 5. Otherwise, if the element has a src attribute specified and its value is
// not the empty string, let selected source be the value of the element's src
// attribute, and selected pixel density be 1.0. Otherwise, let selected
// source be null and selected pixel density be undefined.
const std::string src = GetAttribute("src").value_or("");
// 6. Not needed by Cobalt.
// 7. If selected source is not null, run these substeps:
scoped_refptr<loader::image::CachedImage> cached_image;
if (!src.empty()) {
// 7.1. Resolve selected source, relative to the element. If that is not
// successful, abort these steps.
const GURL& base_url = node_document()->url_as_gurl();
const GURL selected_source = base_url.Resolve(src);
if (!selected_source.is_valid()) {
LOG(WARNING) << src << " cannot be resolved based on " << base_url << ".";
return;
}
// 7.2 Let key be a tuple consisting of the resulting absolute URL, the img
// element's cross origin attribute's mode, and, if that mode is not No
// CORS, the Document object's origin.
// 7.3 If the list of available images contains an entry for key, then set
// the img element to the completely available state, update the
// presentation of the image appropriately, queue a task to fire a simple
// event named load at the img element, and abort these steps.
cached_image = node_document()
->html_element_context()
->image_cache()
->CreateCachedResource(selected_source);
if (cached_image->TryGetResource()) {
PreventGarbageCollectionUntilEventIsDispatched(base::Tokens::load());
return;
}
} else {
// 8. 9. Not needed by Cobalt.
// 10. If selected source is null, then set the element to the broken state,
// queue a task to fire a simple event named error at the img element, and
// abort these steps.
PreventGarbageCollectionUntilEventIsDispatched(base::Tokens::error());
return;
}
// 11. Not needed by Cobalt.
// 12. Do a potentially CORS-enabled fetch of the absolute URL that resulted
// from the earlier step, with the mode being the current state of the
// element's crossorigin content attribute, the origin being the origin of the
// img element's Document, and the default origin behaviour set to taint.
// 13. Not needed by Cobalt.
// 14. If the download was successful, fire a simple event named load at the
// img element. Otherwise, queue a task to first fire a simple event named
// error at the img element.
PreventGarbageCollection();
cached_image_loaded_callback_handler_.reset(
new loader::image::CachedImage::OnLoadedCallbackHandler(
cached_image, base::Bind(&HTMLImageElement::OnLoadingSuccess,
base::Unretained(this)),
base::Bind(&HTMLImageElement::OnLoadingFailure,
base::Unretained(this)),
base::Bind(&HTMLImageElement::OnLoadingError,
base::Unretained(this))));
node_document()->IncreaseLoadingCounter();
}
void HTMLImageElement::OnLoadingSuccess() {
TRACE_EVENT0("cobalt::dom", "HTMLImageElement::OnLoadingSuccess()");
AllowGarbageCollectionAfterEventIsDispatched(base::Tokens::load());
node_document()->DecreaseLoadingCounterAndMaybeDispatchLoadEvent();
cached_image_loaded_callback_handler_.reset();
}
void HTMLImageElement::OnLoadingFailure() {
TRACE_EVENT0("cobalt::dom", "HTMLImageElement::OnLoadingFailure()");
// No event is dispatched.
AllowGarbageCollection();
node_document()->DecreaseLoadingCounterAndMaybeDispatchLoadEvent();
cached_image_loaded_callback_handler_.reset();
}
void HTMLImageElement::OnLoadingError() {
TRACE_EVENT0("cobalt::dom", "HTMLImageElement::OnLoadingError()");
AllowGarbageCollectionAfterEventIsDispatched(base::Tokens::error());
node_document()->DecreaseLoadingCounterAndMaybeDispatchLoadEvent();
cached_image_loaded_callback_handler_.reset();
}
void HTMLImageElement::PreventGarbageCollectionUntilEventIsDispatched(
base::Token event_name) {
PreventGarbageCollection();
AllowGarbageCollectionAfterEventIsDispatched(event_name);
}
void HTMLImageElement::AllowGarbageCollectionAfterEventIsDispatched(
base::Token event_name) {
PostToDispatchEventAndRunCallback(
FROM_HERE, event_name,
base::Bind(&HTMLImageElement::AllowGarbageCollection,
base::AsWeakPtr<HTMLImageElement>(this)));
}
void HTMLImageElement::PreventGarbageCollection() {
DCHECK(thread_checker_.CalledOnValidThread());
DCHECK_GE(prevent_garbage_collection_count_, 0);
if (prevent_garbage_collection_count_++ == 0) {
DCHECK(html_element_context()->script_runner());
DCHECK(html_element_context()->script_runner()->GetGlobalEnvironment());
html_element_context()
->script_runner()
->GetGlobalEnvironment()
->PreventGarbageCollection(make_scoped_refptr(this));
}
}
void HTMLImageElement::AllowGarbageCollection() {
DCHECK(thread_checker_.CalledOnValidThread());
DCHECK_GT(prevent_garbage_collection_count_, 0);
if (--prevent_garbage_collection_count_ == 0) {
DCHECK(html_element_context()->script_runner());
DCHECK(html_element_context()->script_runner()->GetGlobalEnvironment());
html_element_context()
->script_runner()
->GetGlobalEnvironment()
->AllowGarbageCollection(make_scoped_refptr(this));
}
}
} // namespace dom
} // namespace cobalt