1 files changed, 97 insertions, 0 deletions
diff --git a/xpcom/io/nsIUnicharInputStream.idl b/xpcom/io/nsIUnicharInputStream.idl
new file mode 100644
index 0000000000..3ae467cc83
--- /dev/null
+++ b/xpcom/io/nsIUnicharInputStream.idl
@@ -0,0 +1,97 @@
+/* -*- 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 http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIUnicharInputStream;
+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
+ * @param aToOffset number of UTF-16 code units already read
+ *                  (since ReadSegments was called)
+ * @param aCount length of fromSegment
+ * @param aWriteCount number of UTF-16 code units 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 UTF-16 input stream
+ * @see nsIInputStream
+ */
+[scriptable, uuid(d5e3bd80-6723-4b92-b0c9-22f6162fd94f)]
+interface nsIUnicharInputStream : nsISupports {
+  /**
+   * Reads into a caller-provided array.
+   *
+   * @return The number of utf-16 code units 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 code units, 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 UTF-16 code units 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 UTF-16 code units to be read
+   *
+   * @return number of UTF-16 code units 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 UTF-16 code units that should be read
+   * @return The number of UTF-16 code units 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();
+};