michael@0: /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "nsISupports.idl"
michael@0: 
michael@0: interface nsIAsyncInputStream;
michael@0: interface nsIAsyncOutputStream;
michael@0: 
michael@0: /**
michael@0:  * nsIPipe represents an in-process buffer that can be read using nsIInputStream
michael@0:  * and written using nsIOutputStream.  The reader and writer of a pipe do not
michael@0:  * have to be on the same thread.  As a result, the pipe is an ideal mechanism
michael@0:  * to bridge data exchange between two threads.  For example, a worker thread
michael@0:  * might write data to a pipe from which the main thread will read.
michael@0:  *
michael@0:  * Each end of the pipe can be either blocking or non-blocking.  Recall that a
michael@0:  * non-blocking stream will return NS_BASE_STREAM_WOULD_BLOCK if it cannot be
michael@0:  * read or written to without blocking the calling thread.  For example, if you
michael@0:  * try to read from an empty pipe that has not yet been closed, then if that
michael@0:  * pipe's input end is non-blocking, then the read call will fail immediately
michael@0:  * with NS_BASE_STREAM_WOULD_BLOCK as the error condition.  However, if that
michael@0:  * pipe's input end is blocking, then the read call will not return until the
michael@0:  * pipe has data or until the pipe is closed.  This example presumes that the
michael@0:  * pipe is being filled asynchronously on some background thread.
michael@0:  *
michael@0:  * The pipe supports nsIAsyncInputStream and nsIAsyncOutputStream, which give
michael@0:  * the user of a non-blocking pipe the ability to wait for the pipe to become
michael@0:  * ready again.  For example, in the case of an empty non-blocking pipe, the
michael@0:  * user can call AsyncWait on the input end of the pipe to be notified when 
michael@0:  * the pipe has data to read (or when the pipe becomes closed).
michael@0:  *
michael@0:  * NS_NewPipe2 and NS_NewPipe provide convenient pipe constructors.  In most
michael@0:  * cases nsIPipe is not actually used.  It is usually enough to just get
michael@0:  * references to the pipe's input and output end.  In which case, the pipe is
michael@0:  * automatically closed when the respective pipe ends are released.
michael@0:  */
michael@0: [scriptable, uuid(25d0de93-685e-4ea4-95d3-d884e31df63c)]
michael@0: interface nsIPipe : nsISupports
michael@0: {
michael@0:     /**
michael@0:      * initialize this pipe
michael@0:      *
michael@0:      * @param nonBlockingInput
michael@0:      *        true specifies non-blocking input stream behavior
michael@0:      * @param nonBlockingOutput
michael@0:      *        true specifies non-blocking output stream behavior
michael@0:      * @param segmentSize
michael@0:      *        specifies the segment size in bytes (pass 0 to use default value)
michael@0:      * @param segmentCount
michael@0:      *        specifies the max number of segments (pass 0 to use default
michael@0:      *        value).   Passing UINT32_MAX here causes the pipe to have
michael@0:      *        "infinite" space.  This mode can be useful in some cases, but
michael@0:      *        should always be used with caution.  The default value for this
michael@0:      *        parameter is a finite value.
michael@0:      */
michael@0:     void init(in boolean nonBlockingInput,
michael@0:               in boolean nonBlockingOutput,
michael@0:               in unsigned long segmentSize,
michael@0:               in unsigned long segmentCount);
michael@0: 
michael@0:     /**
michael@0:      * The pipe's input end, which also implements nsISearchableInputStream.
michael@0:      */
michael@0:     readonly attribute nsIAsyncInputStream inputStream;
michael@0: 
michael@0:     /**
michael@0:      * The pipe's output end.
michael@0:      */
michael@0:     readonly attribute nsIAsyncOutputStream outputStream;
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * XXX this interface doesn't really belong in here.  It is here because
michael@0:  * currently nsPipeInputStream is the only implementation of this interface.
michael@0:  */
michael@0: [scriptable, uuid(8C39EF62-F7C9-11d4-98F5-001083010E9B)] 
michael@0: interface nsISearchableInputStream : nsISupports
michael@0: {
michael@0:     /**
michael@0:      * Searches for a string in the input stream. Since the stream has a notion
michael@0:      * of EOF, it is possible that the string may at some time be in the 
michael@0:      * buffer, but is is not currently found up to some offset. Consequently,
michael@0:      * both the found and not found cases return an offset:
michael@0:      *    if found, return offset where it was found
michael@0:      *    if not found, return offset of the first byte not searched
michael@0:      * In the case the stream is at EOF and the string is not found, the first
michael@0:      * byte not searched will correspond to the length of the buffer.
michael@0:      */
michael@0:     void search(in string forString, 
michael@0:                 in boolean ignoreCase, 
michael@0:                 out boolean found,
michael@0:                 out unsigned long offsetSearchedTo);
michael@0: };
michael@0: 
michael@0: %{C++
michael@0: 
michael@0: class nsIInputStream;
michael@0: class nsIOutputStream;
michael@0: 
michael@0: /**
michael@0:  * NS_NewPipe2
michael@0:  *
michael@0:  * This function supersedes NS_NewPipe.  It differs from NS_NewPipe in two
michael@0:  * major ways:
michael@0:  *  (1) returns nsIAsyncInputStream and nsIAsyncOutputStream, so it is
michael@0:  *      not necessary to QI in order to access these interfaces.
michael@0:  *  (2) the size of the pipe is determined by the number of segments
michael@0:  *      times the size of each segment.
michael@0:  *
michael@0:  * @param pipeIn
michael@0:  *        resulting input end of the pipe
michael@0:  * @param pipeOut
michael@0:  *        resulting output end of the pipe
michael@0:  * @param nonBlockingInput
michael@0:  *        true specifies non-blocking input stream behavior
michael@0:  * @param nonBlockingOutput
michael@0:  *        true specifies non-blocking output stream behavior
michael@0:  * @param segmentSize
michael@0:  *        specifies the segment size in bytes (pass 0 to use default value)
michael@0:  * @param segmentCount
michael@0:  *        specifies the max number of segments (pass 0 to use default value)
michael@0:  *        passing UINT32_MAX here causes the pipe to have "infinite" space.
michael@0:  *        this mode can be useful in some cases, but should always be used with
michael@0:  *        caution.  the default value for this parameter is a finite value.
michael@0:  */
michael@0: extern nsresult
michael@0: NS_NewPipe2(nsIAsyncInputStream **pipeIn,
michael@0:             nsIAsyncOutputStream **pipeOut,
michael@0:             bool nonBlockingInput = false,
michael@0:             bool nonBlockingOutput = false,
michael@0:             uint32_t segmentSize = 0,
michael@0:             uint32_t segmentCount = 0);
michael@0: 
michael@0: /**
michael@0:  * NS_NewPipe
michael@0:  *
michael@0:  * Preserved for backwards compatibility.  Plus, this interface is more
michael@0:  * amiable in certain contexts (e.g., when you don't need the pipe's async
michael@0:  * capabilities).
michael@0:  *
michael@0:  * @param pipeIn
michael@0:  *        resulting input end of the pipe
michael@0:  * @param pipeOut
michael@0:  *        resulting output end of the pipe
michael@0:  * @param segmentSize
michael@0:  *        specifies the segment size in bytes (pass 0 to use default value)
michael@0:  * @param maxSize
michael@0:  *        specifies the max size of the pipe (pass 0 to use default value)
michael@0:  *        number of segments is maxSize / segmentSize, and maxSize must be a
michael@0:  *        multiple of segmentSize.  passing UINT32_MAX here causes the
michael@0:  *        pipe to have "infinite" space.  this mode can be useful in some
michael@0:  *        cases, but should always be used with caution.  the default value
michael@0:  *        for this parameter is a finite value.
michael@0:  * @param nonBlockingInput
michael@0:  *        true specifies non-blocking input stream behavior
michael@0:  * @param nonBlockingOutput
michael@0:  *        true specifies non-blocking output stream behavior
michael@0:  */
michael@0: extern nsresult
michael@0: NS_NewPipe(nsIInputStream **pipeIn,
michael@0:            nsIOutputStream **pipeOut,
michael@0:            uint32_t segmentSize = 0,
michael@0:            uint32_t maxSize = 0,
michael@0:            bool nonBlockingInput = false,
michael@0:            bool nonBlockingOutput = false);
michael@0: 
michael@0: %}