michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* vim:set ts=2 sw=2 sts=2 et cindent: */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "nsIRequest.idl"
michael@0: 
michael@0: interface nsIURI;
michael@0: interface nsIFile;
michael@0: interface nsIRequestObserver;
michael@0: 
michael@0: /**
michael@0:  * An incremental download object attempts to fetch a file piecemeal over time
michael@0:  * in an effort to minimize network bandwidth usage.
michael@0:  *
michael@0:  * Canceling a background download does not cause the file on disk to be
michael@0:  * deleted.
michael@0:  */
michael@0: [scriptable, uuid(6687823f-56c4-461d-93a1-7f6cb7dfbfba)]
michael@0: interface nsIIncrementalDownload : nsIRequest
michael@0: {
michael@0:   /**
michael@0:    * Initialize the incremental download object.  If the destination file
michael@0:    * already exists, then only the remaining portion of the file will be
michael@0:    * fetched.
michael@0:    *
michael@0:    * NOTE: The downloader will create the destination file if it does not
michael@0:    * already exist.  It will create the file with the permissions 0600 if
michael@0:    * needed.  To affect the permissions of the file, consumers of this
michael@0:    * interface may create an empty file at the specified destination prior to
michael@0:    * starting the incremental download.
michael@0:    *
michael@0:    * NOTE: Since this class may create a temporary file at the specified
michael@0:    * destination, it is advisable for the consumer of this interface to specify
michael@0:    * a file name for the destination that would not tempt the user into
michael@0:    * double-clicking it.  For example, it might be wise to append a file
michael@0:    * extension like ".part" to the end of the destination to protect users from
michael@0:    * accidentally running "blah.exe" before it is a complete file.
michael@0:    *
michael@0:    * @param uri
michael@0:    *        The URI to fetch.
michael@0:    * @param destination
michael@0:    *        The location where the file is to be stored.
michael@0:    * @param chunkSize
michael@0:    *        The size of the chunks to fetch.  A non-positive value results in
michael@0:    *        the default chunk size being used.
michael@0:    * @param intervalInSeconds
michael@0:    *        The amount of time to wait between fetching chunks.  Pass a
michael@0:    *        negative to use the default interval, or 0 to fetch the remaining
michael@0:    *        part of the file in one chunk.
michael@0:    */
michael@0:   void init(in nsIURI uri, in nsIFile destination, in long chunkSize,
michael@0:             in long intervalInSeconds);
michael@0: 
michael@0:   /**
michael@0:    * The URI being fetched.
michael@0:    */
michael@0:   readonly attribute nsIURI URI;
michael@0: 
michael@0:   /**
michael@0:    * The URI being fetched after any redirects have been followed.  This
michael@0:    * attribute is set just prior to calling OnStartRequest on the observer
michael@0:    * passed to the start method.
michael@0:    */
michael@0:   readonly attribute nsIURI finalURI;
michael@0: 
michael@0:   /**
michael@0:    * The file where the download is being written.
michael@0:    */
michael@0:   readonly attribute nsIFile destination;
michael@0: 
michael@0:   /**
michael@0:    * The total number of bytes for the requested file.  This attribute is set
michael@0:    * just prior to calling OnStartRequest on the observer passed to the start
michael@0:    * method.
michael@0:    *
michael@0:    * This attribute has a value of -1 if the total size is unknown.
michael@0:    */
michael@0:   readonly attribute long long totalSize;
michael@0: 
michael@0:   /**
michael@0:    * The current number of bytes downloaded so far.  This attribute is set just
michael@0:    * prior to calling OnStartRequest on the observer passed to the start
michael@0:    * method.
michael@0:    *
michael@0:    * This attribute has a value of -1 if the current size is unknown.
michael@0:    */
michael@0:   readonly attribute long long currentSize;
michael@0: 
michael@0:   /**
michael@0:    * Start the incremental download.
michael@0:    *
michael@0:    * @param observer
michael@0:    *        An observer to be notified of various events.  OnStartRequest is
michael@0:    *        called when finalURI and totalSize have been determined or when an
michael@0:    *        error occurs.  OnStopRequest is called when the file is completely
michael@0:    *        downloaded or when an error occurs.  If this object implements
michael@0:    *        nsIProgressEventSink, then its OnProgress method will be called as
michael@0:    *        data is written to the destination file.  If this object implements
michael@0:    *        nsIInterfaceRequestor, then it will be assigned as the underlying
michael@0:    *        channel's notification callbacks, which allows it to provide a
michael@0:    *        nsIAuthPrompt implementation if needed by the channel, for example.
michael@0:    * @param ctxt
michael@0:    *        User defined object forwarded to the observer's methods.
michael@0:    */
michael@0:   void start(in nsIRequestObserver observer,
michael@0:              in nsISupports ctxt);
michael@0: };