public void AddPage(BTreePage page)
{
// It is not clear whether new BTree pages should be marked as internal or not
// Outlook sometimes chooses to mark them as internal, and sometimes not (for both BBT and NBT)
page.BlockID = m_file.Header.AllocateNextPageBlockID();
m_pageBuffer.Add(page.BlockID.Value, page);
m_pagesToWrite.Add(page.BlockID.Value);
}
/// <summary>
/// After modifying a page, we must update its parent's BlockID to refer to the new page
/// </summary>
protected void UpdatePageAndReferences(BTreePage page)
{
ulong currentBlockID = page.BlockID.Value;
UpdatePage(page);
if (currentBlockID != page.BlockID.Value &&
page.ParentPage != null)
{
// we must update the parent to refer to the new page,
// and cascade the changes up to the root page
CascadeUpReferenceUpdate(page.ParentPage, currentBlockID, page.BlockID.Value);
}
}
public BTreePage GetPage(BlockRef blockRef)
{
ulong blockID = blockRef.bid.Value;
if (m_pageBuffer.ContainsKey(blockID))
{
return(m_pageBuffer[blockID]);
}
else
{
BTreePage page = BTreePage.ReadFromStream(m_file.BaseStream, blockRef);
m_pageBuffer.Add(blockRef.bid.Value, page);
return(page);
}
}
private static int CompareByCLevel(BTreePage x, BTreePage y)
{
if (x.cLevel > y.cLevel)
{
return(1);
}
else if (x.cLevel < y.cLevel)
{
return(-1);
}
else
{
return(0);
}
}
public void CreateNewRoot()
{
BTreeIndexPage newRoot = BTreeIndexPage.GetEmptyIndexPage(m_bTreeRootPage.pageTrailer.ptype, m_bTreeRootPage.cLevel + 1);
BTreeIndexEntry rootIndexEntry = new BTreeIndexEntry();
// We make sure the old root page has been updated (to prevent the BlockID from changing during update)
UpdatePage(m_bTreeRootPage);
rootIndexEntry.btkey = m_bTreeRootPage.PageKey;
rootIndexEntry.BREF.bid = m_bTreeRootPage.BlockID;
rootIndexEntry.BREF.ib = 0; // this will tell BufferedBTreePageStore that the block hasn't been written yet
newRoot.IndexEntryList.Add(rootIndexEntry);
AddPage(newRoot);
m_bTreeRootPage.ParentPage = newRoot;
m_bTreeRootPage = newRoot;
}
public void DeletePage(BTreePage page)
{
ulong blockID = page.BlockID.Value;
if (m_pageBuffer.ContainsKey(blockID))
{
// remove the old block from the cache
m_pageBuffer.Remove(blockID);
}
// no need to free a block that has not been written yet
if (IsPagePendingWrite(page))
{
m_pagesToWrite.Remove(blockID);
}
else
{
m_offsetsToFree.Add(page.Offset);
}
}
/// <summary>
/// Find the leaf BTreePage where the entry with the given key should be located
/// We use this method for search and insertion
/// Note: the returned BTreePage will have its ParentPage set (can be traversed up to the bTreeRootPage)
/// </summary>
protected BTreePage FindLeafBTreePage(ulong key)
{
BTreePage currentPage = m_bTreeRootPage;
int cLevel = m_bTreeRootPage.cLevel;
while (cLevel > 0)
{
int matchingIndex = ((BTreeIndexPage)currentPage).GetIndexOfEntryWithMatchingRange(key);
BTreeIndexEntry matchingEntry = ((BTreeIndexPage)currentPage).IndexEntryList[matchingIndex];
BTreePage childPage = GetPage(matchingEntry.BREF);
childPage.ParentPage = (BTreeIndexPage)currentPage;
currentPage = childPage;
cLevel--;
if (cLevel != currentPage.cLevel)
{
throw new Exception("Invalid Page cLevel");
}
}
return(currentPage);
}
public void UpdatePage(BTreePage page)
{
if (IsPagePendingWrite(page))
{
m_pageBuffer[page.BlockID.Value] = page;
}
else
{
ulong oldBlockID = page.BlockID.Value;
if (m_pageBuffer.ContainsKey(oldBlockID))
{
// remove the old block from the buffer
m_pageBuffer.Remove(oldBlockID);
}
m_offsetsToFree.Add(page.Offset);
page.BlockID = m_file.Header.AllocateNextPageBlockID();
m_pageBuffer.Add(page.BlockID.Value, page);
m_pagesToWrite.Add(page.BlockID.Value);
}
}
public BTree(PSTFile file, BTreePage bTreeRootPage) : base(file)
{
m_bTreeRootPage = bTreeRootPage;
}
public BlockBTree(PSTFile file, BTreePage bTreeRootPage) : base(file, bTreeRootPage)
{
}
public bool IsPagePendingWrite(BTreePage page)
{
return(IsPagePendingWrite(page.BlockID.Value));
}
public NodeBTree(PSTFile file, BTreePage bTreeRootPage) : base(file, bTreeRootPage)
{
}
