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