/gecko_sdk/idl/nsIOutputStream.idl

http://firefox-mac-pdf.googlecode.com/ · IDL · 183 lines · 25 code · 10 blank · 148 comment · 0 complexity · df854b9e13a96583584d57c3e8388456 MD5 · raw file

  1. /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
  2. /* ***** BEGIN LICENSE BLOCK *****
  3. * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  4. *
  5. * The contents of this file are subject to the Mozilla Public License Version
  6. * 1.1 (the "License"); you may not use this file except in compliance with
  7. * the License. You may obtain a copy of the License at
  8. * http://www.mozilla.org/MPL/
  9. *
  10. * Software distributed under the License is distributed on an "AS IS" basis,
  11. * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  12. * for the specific language governing rights and limitations under the
  13. * License.
  14. *
  15. * The Original Code is mozilla.org code.
  16. *
  17. * The Initial Developer of the Original Code is
  18. * Netscape Communications Corporation.
  19. * Portions created by the Initial Developer are Copyright (C) 1998
  20. * the Initial Developer. All Rights Reserved.
  21. *
  22. * Contributor(s):
  23. * Warren Harris <warren@netscape.com>
  24. * Darin Fisher <darin@netscape.com>
  25. *
  26. * Alternatively, the contents of this file may be used under the terms of
  27. * either of the GNU General Public License Version 2 or later (the "GPL"),
  28. * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  29. * in which case the provisions of the GPL or the LGPL are applicable instead
  30. * of those above. If you wish to allow use of your version of this file only
  31. * under the terms of either the GPL or the LGPL, and not to allow others to
  32. * use your version of this file under the terms of the MPL, indicate your
  33. * decision by deleting the provisions above and replace them with the notice
  34. * and other provisions required by the GPL or the LGPL. If you do not delete
  35. * the provisions above, a recipient may use your version of this file under
  36. * the terms of any one of the MPL, the GPL or the LGPL.
  37. *
  38. * ***** END LICENSE BLOCK ***** */
  39. #include "nsISupports.idl"
  40. interface nsIOutputStream;
  41. interface nsIInputStream;
  42. %{C++
  43. /**
  44. * The signature for the reader function passed to WriteSegments. This
  45. * is the "provider" of data that gets written into the stream's buffer.
  46. *
  47. * @param aOutStream stream being written to
  48. * @param aClosure opaque parameter passed to WriteSegments
  49. * @param aToSegment pointer to memory owned by the output stream
  50. * @param aFromOffset amount already written (since WriteSegments was called)
  51. * @param aCount length of toSegment
  52. * @param aReadCount number of bytes written
  53. *
  54. * Implementers should return the following:
  55. *
  56. * @return NS_OK and (*aReadCount > 0) if successfully provided some data
  57. * @return NS_OK and (*aReadCount = 0) or
  58. * @return <any-error> if not interested in providing any data
  59. *
  60. * Errors are never passed to the caller of WriteSegments.
  61. *
  62. * @status FROZEN
  63. */
  64. typedef NS_CALLBACK(nsReadSegmentFun)(nsIOutputStream *aOutStream,
  65. void *aClosure,
  66. char *aToSegment,
  67. PRUint32 aFromOffset,
  68. PRUint32 aCount,
  69. PRUint32 *aReadCount);
  70. %}
  71. native nsReadSegmentFun(nsReadSegmentFun);
  72. /**
  73. * nsIOutputStream
  74. *
  75. * An interface describing a writable stream of data. An output stream may be
  76. * "blocking" or "non-blocking" (see the IsNonBlocking method). A blocking
  77. * output stream may suspend the calling thread in order to satisfy a call to
  78. * Close, Flush, Write, WriteFrom, or WriteSegments. A non-blocking output
  79. * stream, on the other hand, must not block the calling thread of execution.
  80. *
  81. * NOTE: blocking output streams are often written to on a background thread to
  82. * avoid locking up the main application thread. For this reason, it is
  83. * generally the case that a blocking output stream should be implemented using
  84. * thread- safe AddRef and Release.
  85. *
  86. * @status FROZEN
  87. */
  88. [scriptable, uuid(0d0acd2a-61b4-11d4-9877-00c04fa0cf4a)]
  89. interface nsIOutputStream : nsISupports
  90. {
  91. /**
  92. * Close the stream. Forces the output stream to flush any buffered data.
  93. *
  94. * @throws NS_BASE_STREAM_WOULD_BLOCK if unable to flush without blocking
  95. * the calling thread (non-blocking mode only)
  96. */
  97. void close();
  98. /**
  99. * Flush the stream.
  100. *
  101. * @throws NS_BASE_STREAM_WOULD_BLOCK if unable to flush without blocking
  102. * the calling thread (non-blocking mode only)
  103. */
  104. void flush();
  105. /**
  106. * Write data into the stream.
  107. *
  108. * @param aBuf the buffer containing the data to be written
  109. * @param aCount the maximum number of bytes to be written
  110. *
  111. * @return number of bytes written (may be less than aCount)
  112. *
  113. * @throws NS_BASE_STREAM_WOULD_BLOCK if writing to the output stream would
  114. * block the calling thread (non-blocking mode only)
  115. * @throws <other-error> on failure
  116. */
  117. unsigned long write(in string aBuf, in unsigned long aCount);
  118. /**
  119. * Writes data into the stream from an input stream.
  120. *
  121. * @param aFromStream the stream containing the data to be written
  122. * @param aCount the maximum number of bytes to be written
  123. *
  124. * @return number of bytes written (may be less than aCount)
  125. *
  126. * @throws NS_BASE_STREAM_WOULD_BLOCK if writing to the output stream would
  127. * block the calling thread (non-blocking mode only)
  128. * @throws <other-error> on failure
  129. *
  130. * NOTE: This method is defined by this interface in order to allow the
  131. * output stream to efficiently copy the data from the input stream into
  132. * its internal buffer (if any). If this method was provided as an external
  133. * facility, a separate char* buffer would need to be used in order to call
  134. * the output stream's other Write method.
  135. */
  136. unsigned long writeFrom(in nsIInputStream aFromStream,
  137. in unsigned long aCount);
  138. /**
  139. * Low-level write method that has access to the stream's underlying buffer.
  140. * The reader function may be called multiple times for segmented buffers.
  141. * WriteSegments is expected to keep calling the reader until either there
  142. * is nothing left to write or the reader returns an error. WriteSegments
  143. * should not call the reader with zero bytes to provide.
  144. *
  145. * @param aReader the "provider" of the data to be written
  146. * @param aClosure opaque parameter passed to reader
  147. * @param aCount the maximum number of bytes to be written
  148. *
  149. * @return number of bytes written (may be less than aCount)
  150. *
  151. * @throws NS_BASE_STREAM_WOULD_BLOCK if writing to the output stream would
  152. * block the calling thread (non-blocking mode only)
  153. * @throws NS_ERROR_NOT_IMPLEMENTED if the stream has no underlying buffer
  154. * @throws <other-error> on failure
  155. *
  156. * NOTE: this function may be unimplemented if a stream has no underlying
  157. * buffer (e.g., socket output stream).
  158. */
  159. [noscript] unsigned long writeSegments(in nsReadSegmentFun aReader,
  160. in voidPtr aClosure,
  161. in unsigned long aCount);
  162. /**
  163. * @return true if stream is non-blocking
  164. *
  165. * NOTE: writing to a blocking output stream will block the calling thread
  166. * until all given data can be consumed by the stream.
  167. *
  168. * NOTE: a non-blocking output stream may implement nsIAsyncOutputStream to
  169. * provide consumers with a way to wait for the stream to accept more data
  170. * once its write method is unable to accept any data without blocking.
  171. */
  172. boolean isNonBlocking();
  173. };