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/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 http://mozilla.org/MPL/2.0/. */
#include "nsISupports.idl"
interface nsIRequest;
interface nsIStreamListener;
interface nsIURI;
/**
* nsIURIContentListener is an interface used by components which
* want to know (and have a chance to handle) a particular content type.
* Typical usage scenarios will include running applications which register
* a nsIURIContentListener for each of its content windows with the uri
* dispatcher service.
*/
[scriptable, uuid(10a28f38-32e8-4c63-8aa1-12eaaebc369a)]
interface nsIURIContentListener : nsISupports
{
/**
* Notifies the content listener to hook up an nsIStreamListener capable of
* consuming the data stream.
*
* @param aContentType Content type of the data.
* @param aIsContentPreferred Indicates whether the content should be
* preferred by this listener.
* @param aRequest Request that is providing the data.
* @param aContentHandler nsIStreamListener that will consume the data.
* This should be set to <code>nullptr</code> if
* this content listener can't handle the content
* type; in this case, doContent should also fail
* (i.e., return failure nsresult).
*
* @return <code>true</code> if the load should
* be aborted and consumer wants to
* handle the load completely by itself. This
* causes the URI Loader do nothing else...
* <code>false</code> if the URI Loader should
* continue handling the load and call the
* returned streamlistener's methods.
*/
boolean doContent(in ACString aContentType,
in boolean aIsContentPreferred,
in nsIRequest aRequest,
out nsIStreamListener aContentHandler);
/**
* When given a uri to dispatch, if the URI is specified as 'preferred
* content' then the uri loader tries to find a preferred content handler
* for the content type. The thought is that many content listeners may
* be able to handle the same content type if they have to. i.e. the mail
* content window can handle text/html just like a browser window content
* listener. However, if the user clicks on a link with text/html content,
* then the browser window should handle that content and not the mail
* window where the user may have clicked the link. This is the difference
* between isPreferred and canHandleContent.
*
* @param aContentType Content type of the data.
* @param aDesiredContentType Indicates that aContentType must be converted
* to aDesiredContentType before processing the
* data. This causes a stream converted to be
* inserted into the nsIStreamListener chain.
* This argument can be <code>nullptr</code> if
* the content should be consumed directly as
* aContentType.
*
* @return <code>true</code> if this is a preferred
* content handler for aContentType;
* <code>false<code> otherwise.
*/
boolean isPreferred(in string aContentType, out string aDesiredContentType);
/**
* When given a uri to dispatch, if the URI is not specified as 'preferred
* content' then the uri loader calls canHandleContent to see if the content
* listener is capable of handling the content.
*
* @param aContentType Content type of the data.
* @param aIsContentPreferred Indicates whether the content should be
* preferred by this listener.
* @param aDesiredContentType Indicates that aContentType must be converted
* to aDesiredContentType before processing the
* data. This causes a stream converted to be
* inserted into the nsIStreamListener chain.
* This argument can be <code>nullptr</code> if
* the content should be consumed directly as
* aContentType.
*
* @return <code>true</code> if the data can be consumed.
* <code>false</code> otherwise.
*
* Note: I really envision canHandleContent as a method implemented
* by the docshell as the implementation is generic to all doc
* shells. The isPreferred decision is a decision made by a top level
* application content listener that sits at the top of the docshell
* hierarchy.
*/
boolean canHandleContent(in string aContentType,
in boolean aIsContentPreferred,
out string aDesiredContentType);
/**
* The load context associated with a particular content listener.
* The URI Loader stores and accesses this value as needed.
*/
attribute nsISupports loadCookie;
/**
* The parent content listener if this particular listener is part of a chain
* of content listeners (i.e. a docshell!)
*
* @note If this attribute is set to an object that implements
* nsISupportsWeakReference, the implementation should get the
* nsIWeakReference and hold that. Otherwise, the implementation
* should not refcount this interface; it should assume that a non
* null value is always valid. In that case, the caller is
* responsible for explicitly setting this value back to null if the
* parent content listener is destroyed.
*/
attribute nsIURIContentListener parentContentListener;
};