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993c03acb1
Differential Revision: https://phabricator.services.mozilla.com/D31769 --HG-- extra : moz-landing-system : lando
172 lines
7.1 KiB
Plaintext
172 lines
7.1 KiB
Plaintext
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "nsISupports.idl"
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interface nsIAsyncInputStream;
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interface nsIAsyncOutputStream;
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/**
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* nsIPipe represents an in-process buffer that can be read using nsIInputStream
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* and written using nsIOutputStream. The reader and writer of a pipe do not
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* have to be on the same thread. As a result, the pipe is an ideal mechanism
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* to bridge data exchange between two threads. For example, a worker thread
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* might write data to a pipe from which the main thread will read.
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*
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* Each end of the pipe can be either blocking or non-blocking. Recall that a
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* non-blocking stream will return NS_BASE_STREAM_WOULD_BLOCK if it cannot be
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* read or written to without blocking the calling thread. For example, if you
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* try to read from an empty pipe that has not yet been closed, then if that
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* pipe's input end is non-blocking, then the read call will fail immediately
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* with NS_BASE_STREAM_WOULD_BLOCK as the error condition. However, if that
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* pipe's input end is blocking, then the read call will not return until the
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* pipe has data or until the pipe is closed. This example presumes that the
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* pipe is being filled asynchronously on some background thread.
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*
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* The pipe supports nsIAsyncInputStream and nsIAsyncOutputStream, which give
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* the user of a non-blocking pipe the ability to wait for the pipe to become
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* ready again. For example, in the case of an empty non-blocking pipe, the
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* user can call AsyncWait on the input end of the pipe to be notified when
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* the pipe has data to read (or when the pipe becomes closed).
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*
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* NS_NewPipe2 and NS_NewPipe provide convenient pipe constructors. In most
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* cases nsIPipe is not actually used. It is usually enough to just get
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* references to the pipe's input and output end. In which case, the pipe is
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* automatically closed when the respective pipe ends are released.
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*/
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[scriptable, uuid(25d0de93-685e-4ea4-95d3-d884e31df63c)]
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interface nsIPipe : nsISupports
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{
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/**
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* initialize this pipe
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*
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* @param nonBlockingInput
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* true specifies non-blocking input stream behavior
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* @param nonBlockingOutput
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* true specifies non-blocking output stream behavior
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* @param segmentSize
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* specifies the segment size in bytes (pass 0 to use default value)
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* @param segmentCount
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* specifies the max number of segments (pass 0 to use default
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* value). Passing UINT32_MAX here causes the pipe to have
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* "infinite" space. This mode can be useful in some cases, but
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* should always be used with caution. The default value for this
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* parameter is a finite value.
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*/
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[must_use] void init(in boolean nonBlockingInput,
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in boolean nonBlockingOutput,
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in unsigned long segmentSize,
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in unsigned long segmentCount);
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/**
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* The pipe's input end, which also implements nsISearchableInputStream.
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* Getting fails if the pipe hasn't been initialized.
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*/
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[must_use] readonly attribute nsIAsyncInputStream inputStream;
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/**
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* The pipe's output end. Getting fails if the pipe hasn't been
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* initialized.
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*/
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[must_use] readonly attribute nsIAsyncOutputStream outputStream;
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};
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/**
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* XXX this interface doesn't really belong in here. It is here because
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* currently nsPipeInputStream is the only implementation of this interface.
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*/
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[scriptable, uuid(8C39EF62-F7C9-11d4-98F5-001083010E9B)]
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interface nsISearchableInputStream : nsISupports
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{
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/**
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* Searches for a string in the input stream. Since the stream has a notion
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* of EOF, it is possible that the string may at some time be in the
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* buffer, but is is not currently found up to some offset. Consequently,
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* both the found and not found cases return an offset:
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* if found, return offset where it was found
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* if not found, return offset of the first byte not searched
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* In the case the stream is at EOF and the string is not found, the first
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* byte not searched will correspond to the length of the buffer.
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*/
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void search(in string forString,
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in boolean ignoreCase,
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out boolean found,
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out unsigned long offsetSearchedTo);
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};
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%{C++
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class nsIInputStream;
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class nsIOutputStream;
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/**
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* NS_NewPipe2
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*
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* This function supersedes NS_NewPipe. It differs from NS_NewPipe in two
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* major ways:
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* (1) returns nsIAsyncInputStream and nsIAsyncOutputStream, so it is
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* not necessary to QI in order to access these interfaces.
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* (2) the size of the pipe is determined by the number of segments
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* times the size of each segment.
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*
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* @param pipeIn
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* resulting input end of the pipe
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* @param pipeOut
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* resulting output end of the pipe
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* @param nonBlockingInput
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* true specifies non-blocking input stream behavior
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* @param nonBlockingOutput
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* true specifies non-blocking output stream behavior
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* @param segmentSize
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* specifies the segment size in bytes (pass 0 to use default value)
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* @param segmentCount
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* specifies the max number of segments (pass 0 to use default value)
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* passing UINT32_MAX here causes the pipe to have "infinite" space.
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* this mode can be useful in some cases, but should always be used with
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* caution. the default value for this parameter is a finite value.
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*/
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extern MOZ_MUST_USE nsresult
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NS_NewPipe2(nsIAsyncInputStream **pipeIn,
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nsIAsyncOutputStream **pipeOut,
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bool nonBlockingInput = false,
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bool nonBlockingOutput = false,
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uint32_t segmentSize = 0,
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uint32_t segmentCount = 0);
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/**
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* NS_NewPipe
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*
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* Preserved for backwards compatibility. Plus, this interface is more
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* amiable in certain contexts (e.g., when you don't need the pipe's async
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* capabilities).
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*
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* @param pipeIn
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* resulting input end of the pipe
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* @param pipeOut
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* resulting output end of the pipe
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* @param segmentSize
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* specifies the segment size in bytes (pass 0 to use default value)
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* @param maxSize
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* specifies the max size of the pipe (pass 0 to use default value)
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* number of segments is maxSize / segmentSize, and maxSize must be a
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* multiple of segmentSize. passing UINT32_MAX here causes the
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* pipe to have "infinite" space. this mode can be useful in some
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* cases, but should always be used with caution. the default value
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* for this parameter is a finite value.
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* @param nonBlockingInput
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* true specifies non-blocking input stream behavior
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* @param nonBlockingOutput
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* true specifies non-blocking output stream behavior
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*/
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extern MOZ_MUST_USE nsresult
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NS_NewPipe(nsIInputStream **pipeIn,
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nsIOutputStream **pipeOut,
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uint32_t segmentSize = 0,
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uint32_t maxSize = 0,
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bool nonBlockingInput = false,
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bool nonBlockingOutput = false);
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%}
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