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