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