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Diffstat (limited to 'xpcom/io/nsIPipe.idl')
| -rw-r--r-- | xpcom/io/nsIPipe.idl | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/xpcom/io/nsIPipe.idl b/xpcom/io/nsIPipe.idl new file mode 100644 index 0000000000..596be92e9f --- /dev/null +++ b/xpcom/io/nsIPipe.idl @@ -0,0 +1,171 @@ +/* -*- 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, which also implements nsISearchableInputStream. + * 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; +}; + +/** + * XXX this interface doesn't really belong in here. It is here because + * currently nsPipeInputStream is the only implementation of this interface. + */ +[scriptable, uuid(8C39EF62-F7C9-11d4-98F5-001083010E9B)] +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. + */ + void search(in string forString, + in boolean ignoreCase, + out boolean found, + out unsigned long offsetSearchedTo); +}; + +%{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 MOZ_MUST_USE nsresult +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 MOZ_MUST_USE nsresult +NS_NewPipe(nsIInputStream **pipeIn, + nsIOutputStream **pipeOut, + uint32_t segmentSize = 0, + uint32_t maxSize = 0, + bool nonBlockingInput = false, + bool nonBlockingOutput = false); + +%} |