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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /xpcom/io/nsStorageStream.h
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
Diffstat (limited to 'xpcom/io/nsStorageStream.h')
-rw-r--r--xpcom/io/nsStorageStream.h73
1 files changed, 73 insertions, 0 deletions
diff --git a/xpcom/io/nsStorageStream.h b/xpcom/io/nsStorageStream.h
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+++ b/xpcom/io/nsStorageStream.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+/*
+ * The storage stream provides an internal buffer that can be filled by a
+ * client using a single output stream. One or more independent input streams
+ * can be created to read the data out non-destructively. The implementation
+ * uses a segmented buffer internally to avoid realloc'ing of large buffers,
+ * with the attendant performance loss and heap fragmentation.
+ */
+
+#ifndef _nsStorageStream_h_
+#define _nsStorageStream_h_
+
+#include "nsIStorageStream.h"
+#include "nsIOutputStream.h"
+#include "nsMemory.h"
+#include "mozilla/Attributes.h"
+
+#define NS_STORAGESTREAM_CID \
+{ /* 669a9795-6ff7-4ed4-9150-c34ce2971b63 */ \
+ 0x669a9795, \
+ 0x6ff7, \
+ 0x4ed4, \
+ {0x91, 0x50, 0xc3, 0x4c, 0xe2, 0x97, 0x1b, 0x63} \
+}
+
+#define NS_STORAGESTREAM_CONTRACTID "@mozilla.org/storagestream;1"
+
+class nsSegmentedBuffer;
+
+class nsStorageStream final
+ : public nsIStorageStream
+ , public nsIOutputStream
+{
+public:
+ nsStorageStream();
+
+ NS_DECL_THREADSAFE_ISUPPORTS
+ NS_DECL_NSISTORAGESTREAM
+ NS_DECL_NSIOUTPUTSTREAM
+
+ friend class nsStorageInputStream;
+
+private:
+ ~nsStorageStream();
+
+ nsSegmentedBuffer* mSegmentedBuffer;
+ uint32_t mSegmentSize; // All segments, except possibly the last, are of this size
+ // Must be power-of-2
+ uint32_t mSegmentSizeLog2; // log2(mSegmentSize)
+ bool mWriteInProgress; // true, if an un-Close'ed output stream exists
+ int32_t mLastSegmentNum; // Last segment # in use, -1 initially
+ char* mWriteCursor; // Pointer to next byte to be written
+ char* mSegmentEnd; // Pointer to one byte after end of segment
+ // containing the write cursor
+ uint32_t mLogicalLength; // Number of bytes written to stream
+
+ nsresult Seek(int32_t aPosition);
+ uint32_t SegNum(uint32_t aPosition)
+ {
+ return aPosition >> mSegmentSizeLog2;
+ }
+ uint32_t SegOffset(uint32_t aPosition)
+ {
+ return aPosition & (mSegmentSize - 1);
+ }
+};
+
+#endif // _nsStorageStream_h_