SegStreamAllocation.cpp

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00001 /*
00002 // $Id: //open/dev/fennel/segment/SegStreamAllocation.cpp#5 $
00003 // Fennel is a library of data storage and processing components.
00004 // Copyright (C) 2006-2009 The Eigenbase Project
00005 // Copyright (C) 2006-2009 SQLstream, Inc.
00006 // Copyright (C) 2006-2009 LucidEra, Inc.
00007 //
00008 // This program is free software; you can redistribute it and/or modify it
00009 // under the terms of the GNU General Public License as published by the Free
00010 // Software Foundation; either version 2 of the License, or (at your option)
00011 // any later version approved by The Eigenbase Project.
00012 //
00013 // This program is distributed in the hope that it will be useful,
00014 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00015 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00016 // GNU General Public License for more details.
00017 //
00018 // You should have received a copy of the GNU General Public License
00019 // along with this program; if not, write to the Free Software
00020 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
00021 */
00022 
00023 #include "fennel/common/CommonPreamble.h"
00024 #include "fennel/segment/SegStreamAllocation.h"
00025 #include "fennel/segment/SegInputStream.h"
00026 #include "fennel/segment/SegOutputStream.h"
00027 
00028 FENNEL_BEGIN_CPPFILE("$Id: //open/dev/fennel/segment/SegStreamAllocation.cpp#5 $");
00029 
00030 SharedSegStreamAllocation SegStreamAllocation::newSegStreamAllocation()
00031 {
00032     return SharedSegStreamAllocation(
00033         new SegStreamAllocation(),
00034         ClosableObjectDestructor());
00035 }
00036 
00037 SegStreamAllocation::SegStreamAllocation()
00038 {
00039     nPagesWritten = 0;
00040 }
00041 
00042 void SegStreamAllocation::beginWrite(SharedSegOutputStream pSegOutputStreamInit)
00043 {
00044     // go from state UNALLOCATED
00045     assert(!pSegOutputStream);
00046     assert(!pSegInputStream);
00047 
00048     // to state WRITING
00049     needsClose = true;
00050     pSegOutputStream = pSegOutputStreamInit;
00051 }
00052 
00053 void SegStreamAllocation::endWrite()
00054 {
00055     // from state WRITING
00056     assert(pSegOutputStream);
00057 
00058     nPagesWritten = pSegOutputStream->getPageCount();
00059 
00060     SegmentAccessor segmentAccessor = pSegOutputStream->getSegmentAccessor();
00061     PageId firstPageId = pSegOutputStream->getFirstPageId();
00062     pSegOutputStream->close();
00063     pSegOutputStream.reset();
00064     if (firstPageId == NULL_PAGE_ID) {
00065         // go directly to UNALLOCATED
00066         return;
00067     }
00068 
00069     // go to state READING
00070     pSegInputStream = SegInputStream::newSegInputStream(
00071         segmentAccessor,
00072         firstPageId);
00073     pSegInputStream->setDeallocate(true);
00074 }
00075 
00076 SharedSegInputStream const &SegStreamAllocation::getInputStream() const
00077 {
00078     return pSegInputStream;
00079 }
00080 
00081 void SegStreamAllocation::closeImpl()
00082 {
00083     if (pSegOutputStream) {
00084         // state WRITING
00085         assert(!pSegInputStream);
00086         // do a fake read; this won't really read the pages, it will just
00087         // deallocate them
00088         endWrite();
00089     }
00090 
00091     if (pSegInputStream) {
00092         // state READING
00093         assert(!pSegOutputStream);
00094         assert(pSegInputStream->isDeallocating());
00095         // this will deallocate all remaining pages as a side-effect
00096         pSegInputStream->close();
00097         pSegInputStream.reset();
00098     } else {
00099         // state UNALLOCATED:  nothing to do
00100     }
00101 
00102     nPagesWritten = 0;
00103 }
00104 
00105 BlockNum SegStreamAllocation::getWrittenPageCount() const
00106 {
00107     if (pSegOutputStream) {
00108         return pSegOutputStream->getPageCount();
00109     } else {
00110         return nPagesWritten;
00111     }
00112 }
00113 
00114 FENNEL_END_CPPFILE("$Id: //open/dev/fennel/segment/SegStreamAllocation.cpp#5 $");
00115 
00116 // End SegStreamAllocation.cpp

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