зеркало из https://github.com/mozilla/pjs.git
563 строки
17 KiB
C++
563 строки
17 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/* vim:set ts=4 sts=4 sw=4 cin et: */
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/* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is Mozilla Communicator client code, released
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* March 31, 1998.
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*
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* The Initial Developer of the Original Code is
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* Netscape Communications Corporation.
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* Portions created by the Initial Developer are Copyright (C) 1998-1999
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Pierre Phaneuf <pp@ludusdesign.com>
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either of the GNU General Public License Version 2 or later (the "GPL"),
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* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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/*
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* The storage stream provides an internal buffer that can be filled by a
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* client using a single output stream. One or more independent input streams
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* can be created to read the data out non-destructively. The implementation
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* uses a segmented buffer internally to avoid realloc'ing of large buffers,
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* with the attendant performance loss and heap fragmentation.
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*/
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#include "nsAlgorithm.h"
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#include "nsStorageStream.h"
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#include "nsSegmentedBuffer.h"
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#include "nsStreamUtils.h"
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#include "nsCOMPtr.h"
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#include "prbit.h"
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#include "nsIInputStream.h"
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#include "nsISeekableStream.h"
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#include "prlog.h"
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#if defined(PR_LOGGING)
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//
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// Log module for StorageStream logging...
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//
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// To enable logging (see prlog.h for full details):
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//
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// set NSPR_LOG_MODULES=StorageStreamLog:5
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// set NSPR_LOG_FILE=nspr.log
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//
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// this enables PR_LOG_DEBUG level information and places all output in
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// the file nspr.log
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//
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static PRLogModuleInfo* sLog = PR_NewLogModule("nsStorageStream");
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#endif
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#define LOG(args) PR_LOG(sLog, PR_LOG_DEBUG, args)
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nsStorageStream::nsStorageStream()
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: mSegmentedBuffer(0), mSegmentSize(0), mWriteInProgress(false),
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mLastSegmentNum(-1), mWriteCursor(0), mSegmentEnd(0), mLogicalLength(0)
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{
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LOG(("Creating nsStorageStream [%p].\n", this));
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}
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nsStorageStream::~nsStorageStream()
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{
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delete mSegmentedBuffer;
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}
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NS_IMPL_THREADSAFE_ISUPPORTS2(nsStorageStream,
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nsIStorageStream,
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nsIOutputStream)
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NS_IMETHODIMP
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nsStorageStream::Init(PRUint32 segmentSize, PRUint32 maxSize,
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nsIMemory *segmentAllocator)
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{
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mSegmentedBuffer = new nsSegmentedBuffer();
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if (!mSegmentedBuffer)
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return NS_ERROR_OUT_OF_MEMORY;
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mSegmentSize = segmentSize;
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mSegmentSizeLog2 = PR_FloorLog2(segmentSize);
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// Segment size must be a power of two
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if (mSegmentSize != ((PRUint32)1 << mSegmentSizeLog2))
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return NS_ERROR_INVALID_ARG;
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return mSegmentedBuffer->Init(segmentSize, maxSize, segmentAllocator);
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}
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NS_IMETHODIMP
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nsStorageStream::GetOutputStream(PRInt32 aStartingOffset,
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nsIOutputStream * *aOutputStream)
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{
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NS_ENSURE_ARG(aOutputStream);
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NS_ENSURE_TRUE(mSegmentedBuffer, NS_ERROR_NOT_INITIALIZED);
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if (mWriteInProgress)
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return NS_ERROR_NOT_AVAILABLE;
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nsresult rv = Seek(aStartingOffset);
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if (NS_FAILED(rv)) return rv;
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// Enlarge the last segment in the buffer so that it is the same size as
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// all the other segments in the buffer. (It may have been realloc'ed
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// smaller in the Close() method.)
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if (mLastSegmentNum >= 0)
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if (mSegmentedBuffer->ReallocLastSegment(mSegmentSize)) {
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// Need to re-Seek, since realloc changed segment base pointer
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rv = Seek(aStartingOffset);
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if (NS_FAILED(rv)) return rv;
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}
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NS_ADDREF(this);
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*aOutputStream = static_cast<nsIOutputStream*>(this);
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mWriteInProgress = true;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsStorageStream::Close()
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{
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NS_ENSURE_TRUE(mSegmentedBuffer, NS_ERROR_NOT_INITIALIZED);
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mWriteInProgress = false;
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PRInt32 segmentOffset = SegOffset(mLogicalLength);
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// Shrink the final segment in the segmented buffer to the minimum size
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// needed to contain the data, so as to conserve memory.
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if (segmentOffset)
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mSegmentedBuffer->ReallocLastSegment(segmentOffset);
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mWriteCursor = 0;
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mSegmentEnd = 0;
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LOG(("nsStorageStream [%p] Close mWriteCursor=%x mSegmentEnd=%x\n",
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this, mWriteCursor, mSegmentEnd));
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return NS_OK;
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}
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NS_IMETHODIMP
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nsStorageStream::Flush()
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{
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return NS_OK;
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}
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NS_IMETHODIMP
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nsStorageStream::Write(const char *aBuffer, PRUint32 aCount, PRUint32 *aNumWritten)
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{
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NS_ENSURE_TRUE(mSegmentedBuffer, NS_ERROR_NOT_INITIALIZED);
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const char* readCursor;
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PRUint32 count, availableInSegment, remaining;
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nsresult rv = NS_OK;
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NS_ENSURE_ARG_POINTER(aNumWritten);
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NS_ENSURE_ARG(aBuffer);
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LOG(("nsStorageStream [%p] Write mWriteCursor=%x mSegmentEnd=%x aCount=%d\n",
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this, mWriteCursor, mSegmentEnd, aCount));
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remaining = aCount;
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readCursor = aBuffer;
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// If no segments have been created yet, create one even if we don't have
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// to write any data; this enables creating an input stream which reads from
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// the very end of the data for any amount of data in the stream (i.e.
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// this stream contains N bytes of data and newInputStream(N) is called),
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// even for N=0 (with the caveat that we require .write("", 0) be called to
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// initialize internal buffers).
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bool firstTime = mSegmentedBuffer->GetSegmentCount() == 0;
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while (remaining || NS_UNLIKELY(firstTime)) {
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firstTime = false;
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availableInSegment = mSegmentEnd - mWriteCursor;
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if (!availableInSegment) {
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mWriteCursor = mSegmentedBuffer->AppendNewSegment();
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if (!mWriteCursor) {
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mSegmentEnd = 0;
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rv = NS_ERROR_OUT_OF_MEMORY;
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goto out;
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}
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mLastSegmentNum++;
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mSegmentEnd = mWriteCursor + mSegmentSize;
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availableInSegment = mSegmentEnd - mWriteCursor;
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LOG(("nsStorageStream [%p] Write (new seg) mWriteCursor=%x mSegmentEnd=%x\n",
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this, mWriteCursor, mSegmentEnd));
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}
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count = NS_MIN(availableInSegment, remaining);
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memcpy(mWriteCursor, readCursor, count);
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remaining -= count;
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readCursor += count;
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mWriteCursor += count;
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LOG(("nsStorageStream [%p] Writing mWriteCursor=%x mSegmentEnd=%x count=%d\n",
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this, mWriteCursor, mSegmentEnd, count));
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};
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out:
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*aNumWritten = aCount - remaining;
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mLogicalLength += *aNumWritten;
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LOG(("nsStorageStream [%p] Wrote mWriteCursor=%x mSegmentEnd=%x numWritten=%d\n",
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this, mWriteCursor, mSegmentEnd, *aNumWritten));
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return rv;
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}
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NS_IMETHODIMP
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nsStorageStream::WriteFrom(nsIInputStream *inStr, PRUint32 count, PRUint32 *_retval)
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{
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return NS_ERROR_NOT_IMPLEMENTED;
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}
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NS_IMETHODIMP
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nsStorageStream::WriteSegments(nsReadSegmentFun reader, void * closure, PRUint32 count, PRUint32 *_retval)
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{
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return NS_ERROR_NOT_IMPLEMENTED;
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}
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NS_IMETHODIMP
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nsStorageStream::IsNonBlocking(bool *aNonBlocking)
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{
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*aNonBlocking = false;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsStorageStream::GetLength(PRUint32 *aLength)
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{
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NS_ENSURE_ARG(aLength);
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*aLength = mLogicalLength;
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return NS_OK;
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}
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// Truncate the buffer by deleting the end segments
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NS_IMETHODIMP
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nsStorageStream::SetLength(PRUint32 aLength)
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{
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NS_ENSURE_TRUE(mSegmentedBuffer, NS_ERROR_NOT_INITIALIZED);
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if (mWriteInProgress)
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return NS_ERROR_NOT_AVAILABLE;
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if (aLength > mLogicalLength)
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return NS_ERROR_INVALID_ARG;
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PRInt32 newLastSegmentNum = SegNum(aLength);
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PRInt32 segmentOffset = SegOffset(aLength);
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if (segmentOffset == 0)
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newLastSegmentNum--;
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while (newLastSegmentNum < mLastSegmentNum) {
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mSegmentedBuffer->DeleteLastSegment();
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mLastSegmentNum--;
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}
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mLogicalLength = aLength;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsStorageStream::GetWriteInProgress(bool *aWriteInProgress)
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{
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NS_ENSURE_ARG(aWriteInProgress);
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*aWriteInProgress = mWriteInProgress;
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return NS_OK;
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}
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NS_METHOD
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nsStorageStream::Seek(PRInt32 aPosition)
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{
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NS_ENSURE_TRUE(mSegmentedBuffer, NS_ERROR_NOT_INITIALIZED);
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// An argument of -1 means "seek to end of stream"
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if (aPosition == -1)
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aPosition = mLogicalLength;
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// Seeking beyond the buffer end is illegal
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if ((PRUint32)aPosition > mLogicalLength)
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return NS_ERROR_INVALID_ARG;
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// Seeking backwards in the write stream results in truncation
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SetLength(aPosition);
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// Special handling for seek to start-of-buffer
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if (aPosition == 0) {
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mWriteCursor = 0;
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mSegmentEnd = 0;
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LOG(("nsStorageStream [%p] Seek mWriteCursor=%x mSegmentEnd=%x\n",
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this, mWriteCursor, mSegmentEnd));
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return NS_OK;
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}
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// Segment may have changed, so reset pointers
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mWriteCursor = mSegmentedBuffer->GetSegment(mLastSegmentNum);
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NS_ASSERTION(mWriteCursor, "null mWriteCursor");
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mSegmentEnd = mWriteCursor + mSegmentSize;
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// Adjust write cursor for current segment offset. This test is necessary
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// because SegNum may reference the next-to-be-allocated segment, in which
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// case we need to be pointing at the end of the last segment.
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PRInt32 segmentOffset = SegOffset(aPosition);
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if (segmentOffset == 0 && (SegNum(aPosition) > (PRUint32) mLastSegmentNum))
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mWriteCursor = mSegmentEnd;
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else
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mWriteCursor += segmentOffset;
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LOG(("nsStorageStream [%p] Seek mWriteCursor=%x mSegmentEnd=%x\n",
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this, mWriteCursor, mSegmentEnd));
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return NS_OK;
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}
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////////////////////////////////////////////////////////////////////////////////
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// There can be many nsStorageInputStreams for a single nsStorageStream
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class nsStorageInputStream : public nsIInputStream
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, public nsISeekableStream
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{
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public:
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nsStorageInputStream(nsStorageStream *aStorageStream, PRUint32 aSegmentSize)
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: mStorageStream(aStorageStream), mReadCursor(0),
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mSegmentEnd(0), mSegmentNum(0),
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mSegmentSize(aSegmentSize), mLogicalCursor(0),
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mStatus(NS_OK)
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{
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NS_ADDREF(mStorageStream);
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}
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NS_DECL_ISUPPORTS
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NS_DECL_NSIINPUTSTREAM
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NS_DECL_NSISEEKABLESTREAM
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private:
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~nsStorageInputStream()
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{
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NS_IF_RELEASE(mStorageStream);
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}
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protected:
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NS_METHOD Seek(PRUint32 aPosition);
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friend class nsStorageStream;
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private:
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nsStorageStream* mStorageStream;
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PRUint32 mReadCursor; // Next memory location to read byte, or NULL
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PRUint32 mSegmentEnd; // One byte past end of current buffer segment
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PRUint32 mSegmentNum; // Segment number containing read cursor
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PRUint32 mSegmentSize; // All segments, except the last, are of this size
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PRUint32 mLogicalCursor; // Logical offset into stream
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nsresult mStatus;
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PRUint32 SegNum(PRUint32 aPosition) {return aPosition >> mStorageStream->mSegmentSizeLog2;}
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PRUint32 SegOffset(PRUint32 aPosition) {return aPosition & (mSegmentSize - 1);}
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};
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NS_IMPL_THREADSAFE_ISUPPORTS2(nsStorageInputStream,
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nsIInputStream,
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nsISeekableStream)
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NS_IMETHODIMP
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nsStorageStream::NewInputStream(PRInt32 aStartingOffset, nsIInputStream* *aInputStream)
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{
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NS_ENSURE_TRUE(mSegmentedBuffer, NS_ERROR_NOT_INITIALIZED);
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nsStorageInputStream *inputStream = new nsStorageInputStream(this, mSegmentSize);
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if (!inputStream)
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return NS_ERROR_OUT_OF_MEMORY;
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NS_ADDREF(inputStream);
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nsresult rv = inputStream->Seek(aStartingOffset);
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if (NS_FAILED(rv)) {
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NS_RELEASE(inputStream);
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return rv;
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}
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*aInputStream = inputStream;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsStorageInputStream::Close()
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{
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mStatus = NS_BASE_STREAM_CLOSED;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsStorageInputStream::Available(PRUint32 *aAvailable)
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{
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if (NS_FAILED(mStatus))
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return mStatus;
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*aAvailable = mStorageStream->mLogicalLength - mLogicalCursor;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsStorageInputStream::Read(char* aBuffer, PRUint32 aCount, PRUint32 *aNumRead)
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{
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return ReadSegments(NS_CopySegmentToBuffer, aBuffer, aCount, aNumRead);
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}
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NS_IMETHODIMP
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nsStorageInputStream::ReadSegments(nsWriteSegmentFun writer, void * closure, PRUint32 aCount, PRUint32 *aNumRead)
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{
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*aNumRead = 0;
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if (mStatus == NS_BASE_STREAM_CLOSED)
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return NS_OK;
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if (NS_FAILED(mStatus))
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return mStatus;
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PRUint32 count, availableInSegment, remainingCapacity, bytesConsumed;
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nsresult rv;
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remainingCapacity = aCount;
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while (remainingCapacity) {
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availableInSegment = mSegmentEnd - mReadCursor;
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if (!availableInSegment) {
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PRUint32 available = mStorageStream->mLogicalLength - mLogicalCursor;
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if (!available)
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goto out;
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mSegmentNum++;
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mReadCursor = 0;
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mSegmentEnd = NS_MIN(mSegmentSize, available);
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availableInSegment = mSegmentEnd;
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}
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const char *cur = mStorageStream->mSegmentedBuffer->GetSegment(mSegmentNum);
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count = NS_MIN(availableInSegment, remainingCapacity);
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rv = writer(this, closure, cur + mReadCursor, aCount - remainingCapacity,
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count, &bytesConsumed);
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if (NS_FAILED(rv) || (bytesConsumed == 0))
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break;
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remainingCapacity -= bytesConsumed;
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mReadCursor += bytesConsumed;
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mLogicalCursor += bytesConsumed;
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};
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out:
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*aNumRead = aCount - remainingCapacity;
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bool isWriteInProgress = false;
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if (NS_FAILED(mStorageStream->GetWriteInProgress(&isWriteInProgress)))
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isWriteInProgress = false;
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if (*aNumRead == 0 && isWriteInProgress)
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return NS_BASE_STREAM_WOULD_BLOCK;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsStorageInputStream::IsNonBlocking(bool *aNonBlocking)
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{
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// TODO: This class should implement nsIAsyncInputStream so that callers
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// have some way of dealing with NS_BASE_STREAM_WOULD_BLOCK errors.
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*aNonBlocking = true;
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return NS_OK;
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}
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NS_IMETHODIMP
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nsStorageInputStream::Seek(PRInt32 aWhence, PRInt64 aOffset)
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{
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if (NS_FAILED(mStatus))
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return mStatus;
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PRInt64 pos = aOffset;
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switch (aWhence) {
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case NS_SEEK_SET:
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break;
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case NS_SEEK_CUR:
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pos += mLogicalCursor;
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break;
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case NS_SEEK_END:
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pos += mStorageStream->mLogicalLength;
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break;
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default:
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NS_NOTREACHED("unexpected whence value");
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return NS_ERROR_UNEXPECTED;
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}
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if (pos == PRInt64(mLogicalCursor))
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return NS_OK;
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return Seek(pos);
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}
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NS_IMETHODIMP
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nsStorageInputStream::Tell(PRInt64 *aResult)
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{
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if (NS_FAILED(mStatus))
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return mStatus;
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LL_UI2L(*aResult, mLogicalCursor);
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return NS_OK;
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}
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NS_IMETHODIMP
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nsStorageInputStream::SetEOF()
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{
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NS_NOTREACHED("nsStorageInputStream::SetEOF");
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|
return NS_ERROR_NOT_IMPLEMENTED;
|
|
}
|
|
|
|
NS_METHOD
|
|
nsStorageInputStream::Seek(PRUint32 aPosition)
|
|
{
|
|
PRUint32 length = mStorageStream->mLogicalLength;
|
|
if (aPosition > length)
|
|
return NS_ERROR_INVALID_ARG;
|
|
|
|
if (length == 0)
|
|
return NS_OK;
|
|
|
|
mSegmentNum = SegNum(aPosition);
|
|
mReadCursor = SegOffset(aPosition);
|
|
PRUint32 available = length - aPosition;
|
|
mSegmentEnd = mReadCursor + NS_MIN(mSegmentSize - mReadCursor, available);
|
|
mLogicalCursor = aPosition;
|
|
return NS_OK;
|
|
}
|
|
|
|
nsresult
|
|
NS_NewStorageStream(PRUint32 segmentSize, PRUint32 maxSize, nsIStorageStream **result)
|
|
{
|
|
NS_ENSURE_ARG(result);
|
|
|
|
nsStorageStream* storageStream = new nsStorageStream();
|
|
if (!storageStream) return NS_ERROR_OUT_OF_MEMORY;
|
|
|
|
NS_ADDREF(storageStream);
|
|
nsresult rv = storageStream->Init(segmentSize, maxSize, nsnull);
|
|
if (NS_FAILED(rv)) {
|
|
NS_RELEASE(storageStream);
|
|
return rv;
|
|
}
|
|
*result = storageStream;
|
|
return NS_OK;
|
|
}
|