On Fri, 2012-05-11 at 16:32 +0100, Caolán McNamara wrote:
> > So - how about the attached diff, hopefully rather easier to review &
> > back-port :-)
>
> Seems sane, though it probably makes sense to tweak the trigger for
> calling buildPageChainCache as the units for nNew there are in bytes
> while the define is in "pages". And we might want to avoid calling it in
> the case of a small relative jump in pages forward.
So I pushed this to master; I attach a speculative back-port to 3.5 -
it gives the rest of the rather substantial speedup we need vs. where we
were; I'd like to get it in. I also tested the
'get-position-of-byte-after-the-end' code path which seems to work
nicely too.
Thanks,
Michael.
--
michael.me...@suse.com <><, Pseudo Engineer, itinerant idiot
>From 3cbfc50821ce4ec44a2c27c097cc88f64f47e2c2 Mon Sep 17 00:00:00 2001
From: Michael Meeks <michael.me...@suse.com>
Date: Fri, 11 May 2012 20:19:21 +0100
Subject: [PATCH] sot: Improve OLE2 offset-to-page computation with a FAT
layout vector
---
sot/source/sdstor/stgstrms.cxx | 85 ++++++++++++++++++++++++++++++++++------
sot/source/sdstor/stgstrms.hxx | 3 +
2 files changed, 76 insertions(+), 12 deletions(-)
diff --git a/sot/source/sdstor/stgstrms.cxx b/sot/source/sdstor/stgstrms.cxx
index 5e6c1ea..8d3d758 100644
--- a/sot/source/sdstor/stgstrms.cxx
+++ b/sot/source/sdstor/stgstrms.cxx
@@ -26,12 +26,12 @@
*
************************************************************************/
+#include <algorithm>
#include <string.h> // memcpy()
-
+#include <sal/log.hxx>
#include <osl/file.hxx>
#include <tools/tempfile.hxx>
-#include <tools/debug.hxx>
#include "sot/stg.hxx"
#include "stgelem.hxx"
@@ -334,6 +334,37 @@ void StgStrm::SetEntry( StgDirEntry& r )
r.SetDirty();
}
+/*
+ * The page chain, is basically a singly linked list of slots each
+ * point to the next page. Instead of traversing the file structure
+ * for this each time build a simple flat in-memory vector list
+ * of pages.
+ */
+bool StgStrm::buildPageChainCache()
+{
+ if (nSize > 0)
+ m_aPagesCache.reserve(nSize/nPageSize);
+
+ sal_Int32 nBgn = nStart;
+ while (nBgn >= 0)
+ {
+ m_aPagesCache.push_back(nBgn);
+ sal_Int32 nOldBgn = nBgn;
+ nBgn = pFat->GetNextPage(nBgn);
+ if (nBgn == nOldBgn)
+ return false;
+ }
+
+ return true;
+}
+
+//See fdo#47644 for a .doc with a vast amount of pages where seeking around the
+//document takes a colossal amount of time
+//
+//There's a cost to building a page cache, so only build one if the number of
+//pages to seek through hits some sufficiently high value where it's worth it.
+#define ARBITRARY_LARGE_AMOUNT_OF_PAGES 8 * 512
+
// Compute page number and offset for the given byte position.
// If the position is behind the size, set the stream right
// behind the EOF.
@@ -353,9 +384,35 @@ sal_Bool StgStrm::Pos2Page( sal_Int32 nBytePos )
nPos = nBytePos;
if( nOld == nNew )
return sal_True;
+
+ if (m_aPagesCache.empty() && nNew > ARBITRARY_LARGE_AMOUNT_OF_PAGES)
+ {
+ SAL_WARN("sot", "kicking off large seek helper\n");
+ buildPageChainCache();
+ }
+
+ if (!m_aPagesCache.empty())
+ {
+ size_t nIdx = nNew / nPageSize;
+
+ // special case: seek to 1st byte of new, unallocated page
+ // (in case the file size is a multiple of the page size)
+ if( nBytePos == nSize && !nOffset && nIdx == m_aPagesCache.size() )
+ {
+ nIdx--;
+ nOffset = nPageSize;
+ }
+
+ if (nIdx < m_aPagesCache.size())
+ {
+ nPage = m_aPagesCache[ nIdx ];
+ return sal_Bool( nPage >= 0 );
+ }
+ }
+
if( nNew > nOld )
{
- // the new position is behind the current, so an incremental
+ // the new position is after the current, so an incremental
// positioning is OK. Set the page relative position
nRel = nNew - nOld;
nBgn = nPage;
@@ -404,6 +461,8 @@ StgPage* StgStrm::GetPhysPage( sal_Int32 nBytePos, sal_Bool bForce )
sal_Bool StgStrm::Copy( sal_Int32 nFrom, sal_Int32 nBytes )
{
+ m_aPagesCache.clear();
+
sal_Int32 nTo = nStart;
sal_Int32 nPgs = ( nBytes + nPageSize - 1 ) / nPageSize;
while( nPgs-- )
@@ -430,6 +489,8 @@ sal_Bool StgStrm::Copy( sal_Int32 nFrom, sal_Int32 nBytes )
sal_Bool StgStrm::SetSize( sal_Int32 nBytes )
{
+ m_aPagesCache.clear();
+
// round up to page size
sal_Int32 nOld = ( ( nSize + nPageSize - 1 ) / nPageSize ) * nPageSize;
sal_Int32 nNew = ( ( nBytes + nPageSize - 1 ) / nPageSize ) * nPageSize;
@@ -528,6 +589,8 @@ sal_Int32 StgFATStrm::GetPage( short nOff, sal_Bool bMake, sal_uInt16 *pnMasterA
{
if( bMake )
{
+ m_aPagesCache.clear();
+
// create a new master page
nFAT = nMaxPage++;
pMaster = rIo.Copy( nFAT, STG_FREE );
@@ -582,6 +645,8 @@ sal_Int32 StgFATStrm::GetPage( short nOff, sal_Bool bMake, sal_uInt16 *pnMasterA
sal_Bool StgFATStrm::SetPage( short nOff, sal_Int32 nNewPage )
{
+ m_aPagesCache.clear();
+
sal_Bool bRes = sal_True;
if( nOff < rIo.aHdr.GetFAT1Size() )
rIo.aHdr.SetFATPage( nOff, nNewPage );
@@ -631,6 +696,8 @@ sal_Bool StgFATStrm::SetPage( short nOff, sal_Int32 nNewPage )
sal_Bool StgFATStrm::SetSize( sal_Int32 nBytes )
{
+ m_aPagesCache.clear();
+
// Set the number of entries to a multiple of the page size
short nOld = (short) ( ( nSize + ( nPageSize - 1 ) ) / nPageSize );
short nNew = (short) (
@@ -747,16 +814,10 @@ void StgDataStrm::Init( sal_Int32 nBgn, sal_Int32 nLen )
{
// determine the actual size of the stream by scanning
// the FAT chain and counting the # of pages allocated
- nSize = 0;
- sal_Int32 nOldBgn = -1;
- while( nBgn >= 0 && nBgn != nOldBgn )
- {
- nOldBgn = nBgn;
- nBgn = pFat->GetNextPage( nBgn );
- if( nBgn == nOldBgn )
+ bool bOk = buildPageChainCache();
+ if (!bOk)
rIo.SetError( ERRCODE_IO_WRONGFORMAT );
- nSize += nPageSize;
- }
+ nSize = m_aPagesCache.size() * nPageSize;
}
}
diff --git a/sot/source/sdstor/stgstrms.hxx b/sot/source/sdstor/stgstrms.hxx
index a6a0ad1..6b1b8c3 100644
--- a/sot/source/sdstor/stgstrms.hxx
+++ b/sot/source/sdstor/stgstrms.hxx
@@ -30,6 +30,7 @@
#define _STGSTRMS_HXX
#include <tools/stream.hxx>
+#include <vector>
class StgIo;
class StgStrm;
@@ -77,6 +78,8 @@ protected:
sal_Int32 nPage; // current logical page
short nOffset; // offset into current page
short nPageSize; // logical page size
+ std::vector<sal_Int32> m_aPagesCache;
+ bool buildPageChainCache();
sal_Bool Copy( sal_Int32 nFrom, sal_Int32 nBytes );
StgStrm( StgIo& );
public:
--
1.7.7
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