nsIPipe.idl revision 677833bc953b6cb418c701facbdcf4aa18d6c44e
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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#include "nsIAsyncInputStream.idl"
#include "nsIAsyncOutputStream.idl"
interface nsIMemory;
/**
* 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.
*/
interface nsIPipe : nsISupports
{
/**
* initialize this pipe
*/
in boolean nonBlockingOutput,
/**
* The pipe's input end, which also implements nsISearchableInputStream.
*/
/**
* The pipe's output end.
*/
};
/**
* XXX this interface doesn't really belong in here. It is here because
* currently nsPipeInputStream is the only implementation of this interface.
*/
interface nsISearchableInputStream : nsISupports
{
/**
* Searches for a string in the input stream. Since the stream has a notion
* of EOF, it is possible that the string may at some time be in the
* buffer, but is is not currently found up to some offset. Consequently,
* both the found and not found cases return an offset:
* if found, return offset where it was found
* if not found, return offset of the first byte not searched
* In the case the stream is at EOF and the string is not found, the first
* byte not searched will correspond to the length of the buffer.
*/
in boolean ignoreCase,
};
%{C++
/**
* NS_NewPipe2
*
* This function supercedes 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 PR_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 segmentAlloc
* pass reference to nsIMemory to have all pipe allocations use this
* allocator (pass null to use the default allocator)
*/
/**
* 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 PR_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
* @param segmentAlloc
* pass reference to nsIMemory to have all pipe allocations use this
* allocator (pass null to use the default allocator)
*/
{
if (segmentSize == 0)
else
return NS_OK;
}
%}