gecko-dev/netwerk/base/public/nsIStreamTransportService.idl

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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/. */
#include "nsISupports.idl"
interface nsITransport;
interface nsIInputStream;
interface nsIOutputStream;
/**
* This service read/writes a stream on a background thread.
*
* Use this service to transform any blocking stream (e.g., file stream)
* into a fully asynchronous stream that can be read/written without
* blocking the main thread.
*/
[scriptable, uuid(51CAC889-ABC6-4948-97A3-4F135A6E7630)]
interface nsIStreamTransportService : nsISupports
{
/**
* CreateInputTransport
*
* @param aStream
* The input stream that will be read on a background thread.
* This stream must implement "blocking" stream semantics.
* @param aStartOffset
* The input stream will be read starting from this offset. Pass
* -1 to read from the current stream offset. NOTE: this parameter
* is ignored if the stream does not support nsISeekableStream.
* @param aReadLimit
* This parameter limits the number of bytes that will be read from
* the input stream. Pass -1 to read everything.
* @param aCloseWhenDone
* Specify this flag to have the input stream closed once its
* contents have been completely read.
*
* @return nsITransport instance.
*/
nsITransport createInputTransport(in nsIInputStream aStream,
in long long aStartOffset,
in long long aReadLimit,
in boolean aCloseWhenDone);
/**
* CreateOutputTransport
*
* @param aStream
* The output stream that will be written to on a background thread.
* This stream must implement "blocking" stream semantics.
* @param aStartOffset
* The output stream will be written starting at this offset. Pass
* -1 to write to the current stream offset. NOTE: this parameter
* is ignored if the stream does not support nsISeekableStream.
* @param aWriteLimit
* This parameter limits the number of bytes that will be written to
* the output stream. Pass -1 for unlimited writing.
* @param aCloseWhenDone
* Specify this flag to have the output stream closed once its
* contents have been completely written.
*
* @return nsITransport instance.
*/
nsITransport createOutputTransport(in nsIOutputStream aStream,
in long long aStartOffset,
in long long aWriteLimit,
in boolean aCloseWhenDone);
/**
* Raise the maximum number of active threads by one.
*
* Calling this method won't create any additional thread synchronously.
* It will be only created when it's needed (lazily).
*
* Used by mozilla::dom::file::FileService to increase the maximum number
* of active threads in the thread pool for asynchronous file IO.
*/
void raiseThreadLimit();
/**
* Lower the maximum number of active threads by one.
* lowerThreadLimit() should be always paired with raiseThreadLimit().
*
* Calling this method won't destroy any already running thread
* synchronously. It will be only destroyed when it's done with
* currently running event.
*
* This will never lower the maximum number of active threads beyond
* the internal limit.
*
* @throws NS_ERROR_UNEXPECTED
* When trying to lower the maximum number of active threads
* beyond the internal limit (for example in the case of badly
* nested calls)
*/
void lowerThreadLimit();
};