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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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 nsIAsyncInputStream;
interface nsIAsyncOutputStream;
/**
* nsIPipe represents an in-process buffer that can be read using nsIInputStream
* and written using nsIOutputStream. The reader and writer of a pipe do not
* have to be on the same thread. As a result, the pipe is an ideal mechanism
* to bridge data exchange between two threads. For example, a worker thread
* might write data to a pipe from which the main thread will read.
*
* Each end of the pipe can be either blocking or non-blocking. Recall that a
* non-blocking stream will return NS_BASE_STREAM_WOULD_BLOCK if it cannot be
* read or written to without blocking the calling thread. For example, if you
* try to read from an empty pipe that has not yet been closed, then if that
* pipe's input end is non-blocking, then the read call will fail immediately
* with NS_BASE_STREAM_WOULD_BLOCK as the error condition. However, if that
* pipe's input end is blocking, then the read call will not return until the
* pipe has data or until the pipe is closed. This example presumes that the
* pipe is being filled asynchronously on some background thread.
*
* The pipe supports nsIAsyncInputStream and nsIAsyncOutputStream, which give
* the user of a non-blocking pipe the ability to wait for the pipe to become
* ready again. For example, in the case of an empty non-blocking pipe, the
* user can call AsyncWait on the input end of the pipe to be notified when
* the pipe has data to read (or when the pipe becomes closed).
*
* NS_NewPipe2 and NS_NewPipe provide convenient pipe constructors. In most
* cases nsIPipe is not actually used. It is usually enough to just get
* references to the pipe's input and output end. In which case, the pipe is
* automatically closed when the respective pipe ends are released.
*/
[scriptable, uuid(25d0de93-685e-4ea4-95d3-d884e31df63c)]
interface nsIPipe : nsISupports
{
/**
* initialize this pipe
*
* @param nonBlockingInput
* true specifies non-blocking input stream behavior
* @param nonBlockingOutput
* true specifies non-blocking output stream behavior
* @param segmentSize
* specifies the segment size in bytes (pass 0 to use default value)
* @param segmentCount
* specifies the max number of segments (pass 0 to use default
* value). Passing UINT32_MAX here causes the pipe to have
* "infinite" space. This mode can be useful in some cases, but
* should always be used with caution. The default value for this
* parameter is a finite value.
*/
[must_use] void init(in boolean nonBlockingInput,
in boolean nonBlockingOutput,
in unsigned long segmentSize,
in unsigned long segmentCount);
/**
* The pipe's input end. Getting fails if the pipe hasn't been
* initialized.
*/
[must_use] readonly attribute nsIAsyncInputStream inputStream;
/**
* The pipe's output end. Getting fails if the pipe hasn't been
* initialized.
*/
[must_use] readonly attribute nsIAsyncOutputStream outputStream;
};
%{C++
class nsIInputStream;
class nsIOutputStream;
/**
* NS_NewPipe2
*
* This function supersedes NS_NewPipe. It differs from NS_NewPipe in two
* major ways:
* (1) returns nsIAsyncInputStream and nsIAsyncOutputStream, so it is
* not necessary to QI in order to access these interfaces.
* (2) the size of the pipe is determined by the number of segments
* times the size of each segment.
*
* @param pipeIn
* resulting input end of the pipe
* @param pipeOut
* resulting output end of the pipe
* @param nonBlockingInput
* true specifies non-blocking input stream behavior
* @param nonBlockingOutput
* true specifies non-blocking output stream behavior
* @param segmentSize
* specifies the segment size in bytes (pass 0 to use default value)
* @param segmentCount
* specifies the max number of segments (pass 0 to use default value)
* passing UINT32_MAX here causes the pipe to have "infinite" space.
* this mode can be useful in some cases, but should always be used with
* caution. the default value for this parameter is a finite value.
*/
extern void
NS_NewPipe2(nsIAsyncInputStream **pipeIn,
nsIAsyncOutputStream **pipeOut,
bool nonBlockingInput = false,
bool nonBlockingOutput = false,
uint32_t segmentSize = 0,
uint32_t segmentCount = 0);
/**
* NS_NewPipe
*
* Preserved for backwards compatibility. Plus, this interface is more
* amiable in certain contexts (e.g., when you don't need the pipe's async
* capabilities).
*
* @param pipeIn
* resulting input end of the pipe
* @param pipeOut
* resulting output end of the pipe
* @param segmentSize
* specifies the segment size in bytes (pass 0 to use default value)
* @param maxSize
* specifies the max size of the pipe (pass 0 to use default value)
* number of segments is maxSize / segmentSize, and maxSize must be a
* multiple of segmentSize. passing UINT32_MAX here causes the
* pipe to have "infinite" space. this mode can be useful in some
* cases, but should always be used with caution. the default value
* for this parameter is a finite value.
* @param nonBlockingInput
* true specifies non-blocking input stream behavior
* @param nonBlockingOutput
* true specifies non-blocking output stream behavior
*/
extern void
NS_NewPipe(nsIInputStream **pipeIn,
nsIOutputStream **pipeOut,
uint32_t segmentSize = 0,
uint32_t maxSize = 0,
bool nonBlockingInput = false,
bool nonBlockingOutput = false);
%}
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