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Diffstat (limited to '')
| -rw-r--r-- | xpcom/io/nsIOutputStream.idl | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/xpcom/io/nsIOutputStream.idl b/xpcom/io/nsIOutputStream.idl new file mode 100644 index 0000000000..6bb5a55123 --- /dev/null +++ b/xpcom/io/nsIOutputStream.idl @@ -0,0 +1,145 @@ +/* -*- Mode: C++; tab-width: 2; 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 nsIOutputStream; +interface nsIInputStream; + +%{C++ +/** + * The signature for the reader function passed to WriteSegments. This + * is the "provider" of data that gets written into the stream's buffer. + * + * @param aOutStream stream being written to + * @param aClosure opaque parameter passed to WriteSegments + * @param aToSegment pointer to memory owned by the output stream + * @param aFromOffset amount already written (since WriteSegments was called) + * @param aCount length of toSegment + * @param aReadCount number of bytes written + * + * Implementers should return the following: + * + * @throws <any-error> if not interested in providing any data + * + * Errors are never passed to the caller of WriteSegments. + */ +typedef nsresult (*nsReadSegmentFun)(nsIOutputStream *aOutStream, + void *aClosure, + char *aToSegment, + uint32_t aFromOffset, + uint32_t aCount, + uint32_t *aReadCount); +%} + +native nsReadSegmentFun(nsReadSegmentFun); + +/** + * nsIOutputStream + * + * An interface describing a writable stream of data. An output stream may be + * "blocking" or "non-blocking" (see the IsNonBlocking method). A blocking + * output stream may suspend the calling thread in order to satisfy a call to + * Close, Flush, Write, WriteFrom, or WriteSegments. A non-blocking output + * stream, on the other hand, must not block the calling thread of execution. + * + * NOTE: blocking output streams are often written to on a background thread to + * avoid locking up the main application thread. For this reason, it is + * generally the case that a blocking output stream should be implemented using + * thread- safe AddRef and Release. + */ +[scriptable, builtinclass, uuid(0d0acd2a-61b4-11d4-9877-00c04fa0cf4a)] +interface nsIOutputStream : nsISupports +{ + /** + * Close the stream. Forces the output stream to flush any buffered data. + * + * @throws NS_BASE_STREAM_WOULD_BLOCK if unable to flush without blocking + * the calling thread (non-blocking mode only) + */ + void close(); + + /** + * Flush the stream. + * + * @throws NS_BASE_STREAM_WOULD_BLOCK if unable to flush without blocking + * the calling thread (non-blocking mode only) + */ + void flush(); + + /** + * Write data into the stream. + * + * @param aBuf the buffer containing the data to be written + * @param aCount the maximum number of bytes to be written + * + * @return number of bytes written (may be less than aCount) + * + * @throws NS_BASE_STREAM_WOULD_BLOCK if writing to the output stream would + * block the calling thread (non-blocking mode only) + * @throws <other-error> on failure + */ + unsigned long write(in string aBuf, in unsigned long aCount); + + /** + * Writes data into the stream from an input stream. + * + * @param aFromStream the stream containing the data to be written + * @param aCount the maximum number of bytes to be written + * + * @return number of bytes written (may be less than aCount) + * + * @throws NS_BASE_STREAM_WOULD_BLOCK if writing to the output stream would + * block the calling thread (non-blocking mode only). This failure + * means no bytes were transferred. + * @throws <other-error> on failure + * + * NOTE: This method is defined by this interface in order to allow the + * output stream to efficiently copy the data from the input stream into + * its internal buffer (if any). If this method was provided as an external + * facility, a separate char* buffer would need to be used in order to call + * the output stream's other Write method. + */ + unsigned long writeFrom(in nsIInputStream aFromStream, + in unsigned long aCount); + + /** + * Low-level write method that has access to the stream's underlying buffer. + * The reader function may be called multiple times for segmented buffers. + * WriteSegments is expected to keep calling the reader until either there + * is nothing left to write or the reader returns an error. WriteSegments + * should not call the reader with zero bytes to provide. + * + * @param aReader the "provider" of the data to be written + * @param aClosure opaque parameter passed to reader + * @param aCount the maximum number of bytes to be written + * + * @return number of bytes written (may be less than aCount) + * + * @throws NS_BASE_STREAM_WOULD_BLOCK if writing to the output stream would + * block the calling thread (non-blocking mode only). This failure + * means no bytes were transferred. + * @throws NS_ERROR_NOT_IMPLEMENTED if the stream has no underlying buffer + * @throws <other-error> on failure + * + * NOTE: this function may be unimplemented if a stream has no underlying + * buffer (e.g., socket output stream). + */ + [noscript] unsigned long writeSegments(in nsReadSegmentFun aReader, + in voidPtr aClosure, + in unsigned long aCount); + + /** + * @return true if stream is non-blocking + * + * NOTE: writing to a blocking output stream will block the calling thread + * until all given data can be consumed by the stream. + * + * NOTE: a non-blocking output stream may implement nsIAsyncOutputStream to + * provide consumers with a way to wait for the stream to accept more data + * once its write method is unable to accept any data without blocking. + */ + boolean isNonBlocking(); +}; |