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+/* -*- Mode: C++; tab-width: 4; 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 nsIInputStream;
+interface nsIOutputStream;
+
+/**
+ * The nsIStorageStream interface maintains an internal data buffer that can be
+ * filled using a single output stream. One or more independent input streams
+ * can be created to read the data from the buffer non-destructively.
+ */
+
+[scriptable, uuid(44a200fe-6c2b-4b41-b4e3-63e8c14e7c0d)]
+interface nsIStorageStream : nsISupports
+{
+ /**
+ *
+ * Initialize the stream, setting up the amount of space that will be
+ * allocated for the stream's backing-store.
+ *
+ * @param segmentSize
+ * Size of each segment. Must be a power of two.
+ * @param maxSize
+ * Maximum total size of this stream. length will always be less
+ * than or equal to this value. Passing UINT32_MAX is safe.
+ */
+ void init(in uint32_t segmentSize, in uint32_t maxSize);
+
+ /**
+ * Get a reference to the one and only output stream for this instance.
+ * The zero-based startPosition argument is used is used to set the initial
+ * write cursor position. The startPosition cannot be set larger than the
+ * current buffer length. Calling this method has the side-effect of
+ * truncating the internal buffer to startPosition bytes.
+ */
+ nsIOutputStream getOutputStream(in int32_t startPosition);
+
+ /**
+ * Create a new input stream to read data (written by the singleton output
+ * stream) from the internal buffer. Multiple, independent input streams
+ * can be created.
+ */
+ nsIInputStream newInputStream(in int32_t startPosition);
+
+ /**
+ * The length attribute indicates the total number of bytes stored in the
+ * nsIStorageStream internal buffer, regardless of any consumption by input
+ * streams. Assigning to the length field can be used to truncate the
+ * buffer data, but can not be used when either the instance's output
+ * stream is in use.
+ *
+ * @See #writeInProgress */
+ attribute uint32_t length;
+
+ /**
+ * True, when output stream has not yet been Close'ed
+ */
+ readonly attribute boolean writeInProgress;
+};
+
+%{C++
+// Factory method
+nsresult
+NS_NewStorageStream(uint32_t segmentSize, uint32_t maxSize, nsIStorageStream **result);
+%}