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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 */
#include "nsISupports.idl"
interface nsIUnicharInputStream;
interface nsIInputStream;
* The signature of the writer function passed to ReadSegments. This
* is the "consumer" of data that gets read from the stream's buffer.
* @param aInStream stream being read
* @param aClosure opaque parameter passed to ReadSegments
* @param aFromSegment pointer to memory owned by the input stream
* @param aToOffset amount already read (since ReadSegments was called)
* @param aCount length of fromSegment
* @param aWriteCount number of bytes read
* Implementers should return the following:
* @throws <any-error> if not interested in consuming any data
* Errors are never passed to the caller of ReadSegments.
* NOTE: returning NS_OK and (*aWriteCount = 0) has undefined behavior.
typedef nsresult (*nsWriteUnicharSegmentFun)(nsIUnicharInputStream *aInStream,
void *aClosure,
const char16_t *aFromSegment,
uint32_t aToOffset,
uint32_t aCount,
uint32_t *aWriteCount);
native nsWriteUnicharSegmentFun(nsWriteUnicharSegmentFun);
* Abstract unicode character input stream
* @see nsIInputStream
[scriptable, uuid(d5e3bd80-6723-4b92-b0c9-22f6162fd94f)]
interface nsIUnicharInputStream : nsISupports {
* Reads into a caller-provided character array.
* @return The number of characters that were successfully read. May be less
* than aCount, even if there is more data in the input stream.
* A return value of 0 means EOF.
* @note To read more than 2^32 characters, call this method multiple times.
[noscript] unsigned long read([array, size_is(aCount)] in char16_t aBuf,
in unsigned long aCount);
* Low-level read method that has access to the stream's underlying buffer.
* The writer function may be called multiple times for segmented buffers.
* ReadSegments is expected to keep calling the writer until either there is
* nothing left to read or the writer returns an error. ReadSegments should
* not call the writer with zero characters to consume.
* @param aWriter the "consumer" of the data to be read
* @param aClosure opaque parameter passed to writer
* @param aCount the maximum number of characters to be read
* @return number of characters read (may be less than aCount)
* @return 0 if reached end of file (or if aWriter refused to consume data)
* @throws NS_BASE_STREAM_WOULD_BLOCK if reading from the input stream would
* block the calling thread (non-blocking mode only)
* @throws <other-error> on failure
* NOTE: this function may be unimplemented if a stream has no underlying
* buffer
[noscript] unsigned long readSegments(in nsWriteUnicharSegmentFun aWriter,
in voidPtr aClosure,
in unsigned long aCount);
* Read into a string object.
* @param aCount The number of characters that should be read
* @return The number of characters that were read.
unsigned long readString(in unsigned long aCount, out AString aString);
* Close the stream and free associated resources. This also closes the
* underlying stream, if any.
void close();