| /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ |
| /* ***** BEGIN LICENSE BLOCK ***** |
| * Version: MPL 1.1/GPL 2.0/LGPL 2.1 |
| * |
| * The contents of this file are subject to the Mozilla Public License Version |
| * 1.1 (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * http://www.mozilla.org/MPL/ |
| * |
| * Software distributed under the License is distributed on an "AS IS" basis, |
| * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License |
| * for the specific language governing rights and limitations under the |
| * License. |
| * |
| * The Original Code is mozilla.org code. |
| * |
| * The Initial Developer of the Original Code is |
| * Netscape Communications Corporation. |
| * Portions created by the Initial Developer are Copyright (C) 1998 |
| * the Initial Developer. All Rights Reserved. |
| * |
| * Contributor(s): |
| * Warren Harris <warren@netscape.com> |
| * Darin Fisher <darin@netscape.com> |
| * |
| * Alternatively, the contents of this file may be used under the terms of |
| * either of the GNU General Public License Version 2 or later (the "GPL"), |
| * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), |
| * in which case the provisions of the GPL or the LGPL are applicable instead |
| * of those above. If you wish to allow use of your version of this file only |
| * under the terms of either the GPL or the LGPL, and not to allow others to |
| * use your version of this file under the terms of the MPL, indicate your |
| * decision by deleting the provisions above and replace them with the notice |
| * and other provisions required by the GPL or the LGPL. If you do not delete |
| * the provisions above, a recipient may use your version of this file under |
| * the terms of any one of the MPL, the GPL or the LGPL. |
| * |
| * ***** END LICENSE BLOCK ***** */ |
| |
| #include "nsISupports.idl" |
| |
| interface nsIInputStream; |
| |
| %{C++ |
| /** |
| * 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. This is |
| * where the writer function should start consuming data. |
| * @param aToOffset amount of data already consumed by this writer during this |
| * ReadSegments call. This is also the sum of the aWriteCount |
| * returns from this writer over the previous invocations of |
| * the writer by this ReadSegments call. |
| * @param aCount Number of bytes available to be read starting at aFromSegment |
| * @param [out] aWriteCount number of bytes read by this writer function call |
| * |
| * Implementers should return the following: |
| * |
| * @return NS_OK and (*aWriteCount > 0) if consumed some data |
| * @return <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. |
| * |
| * @status FROZEN |
| */ |
| typedef NS_CALLBACK(nsWriteSegmentFun)(nsIInputStream *aInStream, |
| void *aClosure, |
| const char *aFromSegment, |
| PRUint32 aToOffset, |
| PRUint32 aCount, |
| PRUint32 *aWriteCount); |
| %} |
| |
| native nsWriteSegmentFun(nsWriteSegmentFun); |
| |
| /** |
| * nsIInputStream |
| * |
| * An interface describing a readable stream of data. An input stream may be |
| * "blocking" or "non-blocking" (see the IsNonBlocking method). A blocking |
| * input stream may suspend the calling thread in order to satisfy a call to |
| * Close, Available, Read, or ReadSegments. A non-blocking input stream, on |
| * the other hand, must not block the calling thread of execution. |
| * |
| * NOTE: blocking input streams are often read on a background thread to avoid |
| * locking up the main application thread. For this reason, it is generally |
| * the case that a blocking input stream should be implemented using thread- |
| * safe AddRef and Release. |
| * |
| * @status FROZEN |
| */ |
| [scriptable, uuid(fa9c7f6c-61b3-11d4-9877-00c04fa0cf4a)] |
| interface nsIInputStream : nsISupports |
| { |
| /** |
| * Close the stream. This method causes subsequent calls to Read and |
| * ReadSegments to return 0 bytes read to indicate end-of-file. Any |
| * subsequent calls to Available should throw NS_BASE_STREAM_CLOSED. |
| */ |
| void close(); |
| |
| /** |
| * Determine number of bytes available in the stream. A non-blocking |
| * stream that does not yet have any data to read should return 0 bytes |
| * from this method (i.e., it must not throw the NS_BASE_STREAM_WOULD_BLOCK |
| * exception). |
| * |
| * In addition to the number of bytes available in the stream, this method |
| * also informs the caller of the current status of the stream. A stream |
| * that is closed will throw an exception when this method is called. That |
| * enables the caller to know the condition of the stream before attempting |
| * to read from it. If a stream is at end-of-file, but not closed, then |
| * this method should return 0 bytes available. |
| * |
| * @return number of bytes currently available in the stream, or |
| * PR_UINT32_MAX if the size of the stream exceeds PR_UINT32_MAX. |
| * |
| * @throws NS_BASE_STREAM_CLOSED if the stream is closed normally or at |
| * end-of-file |
| * @throws <other-error> if the stream is closed due to some error |
| * condition |
| */ |
| unsigned long available(); |
| |
| /** |
| * Read data from the stream. |
| * |
| * @param aBuf the buffer into which the data is to be read |
| * @param aCount the maximum number of bytes to be read |
| * |
| * @return number of bytes read (may be less than aCount). |
| * @return 0 if reached end-of-file |
| * |
| * @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 method should not throw NS_BASE_STREAM_CLOSED. |
| */ |
| [noscript] unsigned long read(in charPtr aBuf, in unsigned long aCount); |
| |
| /** |
| * Low-level read method that provides 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 bytes 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 bytes to be read |
| * |
| * @return number of bytes 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 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 input stream). |
| * |
| * NOTE: this method should not throw NS_BASE_STREAM_CLOSED. |
| */ |
| [noscript] unsigned long readSegments(in nsWriteSegmentFun aWriter, |
| in voidPtr aClosure, |
| in unsigned long aCount); |
| |
| /** |
| * @return true if stream is non-blocking |
| * |
| * NOTE: reading from a blocking input stream will block the calling thread |
| * until at least one byte of data can be extracted from the stream. |
| * |
| * NOTE: a non-blocking input stream may implement nsIAsyncInputStream to |
| * provide consumers with a way to wait for the stream to have more data |
| * once its read method is unable to return any data without blocking. |
| */ |
| boolean isNonBlocking(); |
| }; |
