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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at */
* A base class implementing nsIObjectLoadingContent for use by
* various content nodes that want to provide plugin/document/image
* loading functionality (eg <embed>, <object>, etc).
#include "mozilla/Maybe.h"
#include "mozilla/dom/BindingDeclarations.h"
#include "nsIFrame.h" // for WeakFrame only
#include "nsIStreamListener.h"
#include "nsIChannelEventSink.h"
#include "nsIObjectLoadingContent.h"
#include "nsFrameLoaderOwner.h"
class nsStopPluginRunnable;
class nsIPrincipal;
class nsFrameLoader;
namespace mozilla::dom {
struct BindContext;
template <typename T>
class Sequence;
class HTMLIFrameElement;
template <typename T>
struct Nullable;
class WindowProxyHolder;
class XULFrameElement;
} // namespace mozilla::dom
class nsObjectLoadingContent : public nsIStreamListener,
public nsFrameLoaderOwner,
public nsIObjectLoadingContent,
public nsIChannelEventSink {
friend class AutoSetLoadingToFalse;
// This enum's values must be the same as the constants on
// nsIObjectLoadingContent
enum class ObjectType : uint8_t {
// Loading, type not yet known. We may be waiting for a channel to open.
// Content is a subdocument, possibly SVG
// Content is unknown and should be represented by an empty element.
virtual ~nsObjectLoadingContent();
ObjectType Type() const { return mType; }
void SetIsNetworkCreated(bool aNetworkCreated) {
mNetworkCreated = aNetworkCreated;
static bool IsSuccessfulRequest(nsIRequest*, nsresult* aStatus);
mozilla::dom::Document* GetContentDocument(nsIPrincipal& aSubjectPrincipal);
void GetActualType(nsAString& aType) const {
CopyUTF8toUTF16(mContentType, aType);
uint32_t DisplayedType() const { return uint32_t(mType); }
nsIURI* GetSrcURI() const { return mURI; }
void SwapFrameLoaders(mozilla::dom::HTMLIFrameElement& aOtherLoaderOwner,
mozilla::ErrorResult& aRv) {
void SwapFrameLoaders(mozilla::dom::XULFrameElement& aOtherLoaderOwner,
mozilla::ErrorResult& aRv) {
bool IsRewrittenYoutubeEmbed() const { return mRewrittenYoutubeEmbed; }
const mozilla::Maybe<mozilla::IntrinsicSize>& GetSubdocumentIntrinsicSize()
const {
return mSubdocumentIntrinsicSize;
const mozilla::Maybe<mozilla::AspectRatio>& GetSubdocumentIntrinsicRatio()
const {
return mSubdocumentIntrinsicRatio;
void SubdocumentIntrinsicSizeOrRatioChanged(
const mozilla::Maybe<mozilla::IntrinsicSize>& aIntrinsicSize,
const mozilla::Maybe<mozilla::AspectRatio>& aIntrinsicRatio);
void SubdocumentImageLoadComplete(nsresult aResult);
* Begins loading the object when called
* Attributes of |this| QI'd to nsIContent will be inspected, depending on
* the node type. This function currently assumes it is a <object> or
* <embed> tag.
* The instantiated plugin depends on:
* - The URI (<embed src>, <object data>)
* - The type 'hint' (type attribute)
* - The mime type returned by opening the URI
* - Enabled plugins claiming the ultimate mime type
* - The capabilities returned by GetCapabilities
* - The classid attribute, if eFallbackIfClassIDPresent is among the
* capabilities
* If eAllowPluginSkipChannel is true, we may skip opening the URI if our
* type hint points to a valid plugin, deferring that responsibility to the
* plugin.
* Similarly, if no URI is provided, but a type hint for a valid plugin is
* present, that plugin will be instantiated
* Otherwise a request to that URI is made and the type sent by the server
* is used to find a suitable handler, EXCEPT when:
* - The type hint refers to a *supported* plugin, in which case that
* plugin will be instantiated regardless of the server provided type
* - The server returns a binary-stream type, and our type hint refers to
* a valid non-document type, we will use the type hint
* @param aNotify If we should send notifications. If false, content
* loading may be deferred while appropriate frames are
* created
* @param aForceLoad If we should reload this content (and re-attempt the
* channel open) even if our parameters did not change
nsresult LoadObject(bool aNotify, bool aForceLoad = false);
enum Capabilities {
eSupportImages = 1u << 0, // Images are supported (imgILoader)
eSupportDocuments = 1u << 1, // Documents are supported
// (DocumentLoaderFactory)
// This flag always includes SVG
// Node supports class ID as an attribute, and should fallback if it is
// present, as class IDs are not supported.
eFallbackIfClassIDPresent = 1u << 2,
// If possible to get a *plugin* type from the type attribute *or* file
// extension, we can use that type and begin loading the plugin before
// opening a channel.
// A side effect of this is if the channel fails, the plugin is still
// running.
eAllowPluginSkipChannel = 1u << 3
* Returns the list of capabilities this content node supports. This is a
* bitmask consisting of flags from the Capabilities enum.
* The default implementation supports all types but not
* eSupportClassID or eAllowPluginSkipChannel
virtual uint32_t GetCapabilities() const;
* Destroys all loaded documents/plugins and releases references
void Destroy();
// Subclasses should call cycle collection methods from the respective
// traverse / unlink.
static void Traverse(nsObjectLoadingContent* tmp,
nsCycleCollectionTraversalCallback& cb);
static void Unlink(nsObjectLoadingContent* tmp);
void CreateStaticClone(nsObjectLoadingContent* aDest) const;
void UnbindFromTree();
* Return the content policy type used for loading the element.
virtual nsContentPolicyType GetContentPolicyType() const = 0;
virtual const mozilla::dom::Element* AsElement() const = 0;
mozilla::dom::Element* AsElement() {
return const_cast<mozilla::dom::Element*>(
const_cast<const nsObjectLoadingContent*>(this)->AsElement());
* Decides whether we should load <embed>/<object> node content.
* If this is an <embed> or <object> node there are cases in which we should
* not try to load the content:
* - If the node is the child of a media element
* - If the node is the child of an <object> node that already has
* content being loaded.
* In these cases, this function will return false, which will cause
* us to skip calling LoadObject.
bool BlockEmbedOrObjectContentLoading();
// Object parameter changes returned by UpdateObjectParameters
enum ParameterUpdateFlags {
eParamNoChange = 0,
// Parameters that potentially affect the channel changed
// - mOriginalURI, mOriginalContentType
eParamChannelChanged = 1u << 0,
// Parameters that affect displayed content changed
// - mURI, mContentType, mType, mBaseURI
eParamStateChanged = 1u << 1,
// The effective content type changed, independant of object type. This
// can happen when changing from Loading -> Final type, but doesn't
// necessarily happen when changing between object types. E.g., if a PDF
// handler was installed between the last load of this object and now, we
// might change from Document -> Plugin without changing
// ContentType
eParamContentTypeChanged = 1u << 2
* If we're an <object>, and show fallback, we might need to start nested
* <embed> or <object> loads that would otherwise be blocked by
* BlockEmbedOrObjectContentLoading().
void TriggerInnerFallbackLoads();
* Internal version of LoadObject that should only be used by this class
* aLoadingChannel is passed by the LoadObject call from OnStartRequest,
* primarily for sanity-preservation
nsresult LoadObject(bool aNotify, bool aForceLoad,
nsIRequest* aLoadingChannel);
* Inspects the object and sets the following member variables:
* - mOriginalContentType : This is the type attribute on the element
* - mOriginalURI : The src or data attribute on the element
* - mURI : The final URI, considering mChannel if
* mChannelLoaded is set
* - mContentType : The final content type, considering mChannel if
* mChannelLoaded is set
* - mBaseURI : The object's base URI, which may be set by the
* object
* - mType : The type the object is determined to be based
* on the above
* NOTE The class assumes that mType is the currently loaded type at various
* points, so the caller of this function must take the appropriate
* actions to ensure this
* NOTE This function does not perform security checks, only determining the
* requested type and parameters of the object.
* @return Returns a bitmask of ParameterUpdateFlags values
ParameterUpdateFlags UpdateObjectParameters();
bool IsAboutBlankLoadOntoInitialAboutBlank(nsIURI* aURI,
bool aInheritPrincipal,
nsIPrincipal* aPrincipalToInherit);
* Opens the channel pointed to by mURI into mChannel.
nsresult OpenChannel();
* Closes and releases references to mChannel and, if opened, mFinalListener
nsresult CloseChannel();
* If this object should be tested against blocking list.
bool ShouldBlockContent();
* This method tells the final answer on whether this object's fallback
* content should be used instead of the original plugin content.
* @param aIsPluginClickToPlay Whether this object instance is CTP.
bool PreferFallback(bool aIsPluginClickToPlay);
* Helper to check if our current URI passes policy
* @param aContentPolicy [out] The result of the content policy decision
* @return true if call succeeded and NS_CP_ACCEPTED(*aContentPolicy)
bool CheckLoadPolicy(int16_t* aContentPolicy);
* Helper to check if the object passes process policy. Assumes we have a
* final determined type.
* @param aContentPolicy [out] The result of the content policy decision
* @return true if call succeeded and NS_CP_ACCEPTED(*aContentPolicy)
bool CheckProcessPolicy(int16_t* aContentPolicy);
void SetupFrameLoader();
* Helper to spawn mFrameLoader and return a pointer to its docshell
* @param aURI URI we intend to load for the recursive load check (does not
* actually load anything)
already_AddRefed<nsIDocShell> SetupDocShell(nsIURI* aRecursionCheckURI);
* Unloads all content and resets the object to a completely unloaded state
* NOTE Calls StopPluginInstance() and may spin the event loop
* @param aResetState Reset the object type to 'loading' and destroy channel
* as well
void UnloadObject(bool aResetState = true);
* Notifies document observes about a new type/state of this object.
* Triggers frame construction as needed. mType must be set correctly when
* this method is called. This method is cheap if the type and state didn't
* actually change.
* @param aNotify if false, only need to update the state of our element.
void NotifyStateChanged(ObjectType aOldType, bool aNotify);
* Returns a ObjectType value corresponding to the type of content we would
* support the given MIME type as, taking capabilities and plugin state
* into account
* @return The ObjectType enum value that we would attempt to load
* NOTE this does not consider whether the content would be suppressed by
* click-to-play or other content policy checks
ObjectType GetTypeOfContent(const nsCString& aMIMEType);
* Used for identifying whether we can rewrite a youtube flash embed to
* possibly use HTML5 instead.
* Returns true if plugin.rewrite_youtube_embeds pref is true and the
* element this nsObjectLoadingContent instance represents:
* - is an embed or object node
* - has a URL pointing at the domain, using "/v/" style video
* path reference.
* Having the enablejsapi flag means the document that contains the element
* could possibly be manipulating the youtube video elsewhere on the page
* via javascript. In the context of embed elements, this usage has been
* deprecated by youtube, so we can just rewrite as normal.
* If we can rewrite the URL, we change the "/v/" to "/embed/", and change
* our type to Document so that we render similarly to an iframe
* embed.
void MaybeRewriteYoutubeEmbed(nsIURI* aURI, nsIURI* aBaseURI,
nsIURI** aRewrittenURI);
// Utility for firing an error event, if we're an <object>.
void MaybeFireErrorEvent();
* Store feature policy in container browsing context so that it can be
* accessed cross process.
void MaybeStoreCrossOriginFeaturePolicy();
// The final listener for mChannel (uriloader, pluginstreamlistener, etc.)
nsCOMPtr<nsIStreamListener> mFinalListener;
// The content type of our current load target, updated by
// UpdateObjectParameters(). Takes the channel's type into account once
// opened.
// May change if a channel is opened, does not imply a loaded state
nsCString mContentType;
// The content type 'hint' provided by the element's type attribute. May
// or may not be used as a final type
nsCString mOriginalContentType;
// The channel that's currently being loaded. If set, but mChannelLoaded is
// false, has not yet reached OnStartRequest
nsCOMPtr<nsIChannel> mChannel;
// The URI of the current content.
// May change as we open channels and encounter redirects - does not imply
// a loaded type
nsCOMPtr<nsIURI> mURI;
// The original URI obtained from inspecting the element. May differ from
// mURI due to redirects
nsCOMPtr<nsIURI> mOriginalURI;
// The baseURI used for constructing mURI.
nsCOMPtr<nsIURI> mBaseURI;
// Type of the currently-loaded content.
ObjectType mType;
// If true, we have opened a channel as the listener and it has reached
// OnStartRequest. Does not get set for channels that are passed directly to
// the plugin listener.
bool mChannelLoaded : 1;
// True when the object is created for an element which the parser has
// created using NS_FROM_PARSER_NETWORK flag. If the element is modified,
// it may lose the flag.
bool mNetworkCreated : 1;
// Whether content blocking is enabled or not for this object.
bool mContentBlockingEnabled : 1;
// Protects DoStopPlugin from reentry (bug 724781).
bool mIsStopping : 1;
// Protects LoadObject from re-entry
bool mIsLoading : 1;
// For plugin stand-in types (click-to-play) tracks whether content js has
// tried to access the plugin script object.
bool mScriptRequested : 1;
// True if object represents an object/embed tag pointing to a flash embed
// for a youtube video. When possible (see IsRewritableYoutubeEmbed function
// comments for details), we change these to try to load HTML5 versions of
// videos.
bool mRewrittenYoutubeEmbed : 1;
bool mLoadingSyntheticDocument : 1;
// The intrinsic size and aspect ratio from a child SVG document that
// we should use. These are only set when we are an <object> or <embed>
// and the inner document is SVG.
// We store these here rather than on nsSubDocumentFrame since we are
// sometimes notified of our child's intrinsics before we've constructed
// our own frame.
mozilla::Maybe<mozilla::IntrinsicSize> mSubdocumentIntrinsicSize;
mozilla::Maybe<mozilla::AspectRatio> mSubdocumentIntrinsicRatio;