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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
commit26a029d407be480d791972afb5975cf62c9360a6 (patch)
treef435a8308119effd964b339f76abb83a57c29483 /xpcom/io/nsStorageStream.h
parentInitial commit. (diff)
downloadfirefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz
firefox-26a029d407be480d791972afb5975cf62c9360a6.zip
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'xpcom/io/nsStorageStream.h')
-rw-r--r--xpcom/io/nsStorageStream.h79
1 files changed, 79 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 "mozilla/Attributes.h"
+#include "mozilla/Mutex.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();
+
+ mozilla::Mutex mMutex{"nsStorageStream"};
+ nsSegmentedBuffer* mSegmentedBuffer MOZ_GUARDED_BY(mMutex) = nullptr;
+ // All segments, except possibly the last, are of this size. Must be
+ // power-of-2
+ uint32_t mSegmentSize MOZ_GUARDED_BY(mMutex) = 0;
+ // log2(mSegmentSize)
+ uint32_t mSegmentSizeLog2 MOZ_GUARDED_BY(mMutex) = 0;
+ // true, if an un-Close'ed output stream exists
+ bool mWriteInProgress MOZ_GUARDED_BY(mMutex) = false;
+ // Last segment # in use, -1 initially
+ int32_t mLastSegmentNum MOZ_GUARDED_BY(mMutex) = -1;
+ // Pointer to next byte to be written
+ char* mWriteCursor MOZ_GUARDED_BY(mMutex) = nullptr;
+ // Pointer to one byte after end of segment containing the write cursor
+ char* mSegmentEnd MOZ_GUARDED_BY(mMutex) = nullptr;
+ // Maximum number of bytes which may be written to the stream
+ uint32_t mMaxLogicalLength MOZ_GUARDED_BY(mMutex) = 0;
+ // Number of bytes written to stream
+ uint32_t mLogicalLength MOZ_GUARDED_BY(mMutex) = 0;
+ // number of input streams actively reading a segment.
+ uint32_t mActiveSegmentBorrows MOZ_GUARDED_BY(mMutex) = 0;
+
+ nsresult SetLengthLocked(uint32_t aLength) MOZ_REQUIRES(mMutex);
+ nsresult Seek(int32_t aPosition) MOZ_REQUIRES(mMutex);
+ uint32_t SegNum(uint32_t aPosition) MOZ_REQUIRES(mMutex) {
+ return aPosition >> mSegmentSizeLog2;
+ }
+ uint32_t SegOffset(uint32_t aPosition) MOZ_REQUIRES(mMutex) {
+ return aPosition & (mSegmentSize - 1);
+ }
+};
+
+#endif // _nsStorageStream_h_