/// <summary>
/// Removes a page from storage.
/// </summary>
/// <param name="pageIndex">Index of removing page</param>
public void RemovePage(long pageIndex)
{
CheckDisposed();
Lock();
try
{
CheckStorage();
if (_deferredUpdatesMode)
{
_recoveryFile.WriteDeletePageRecord(pageIndex);
}
else
{
if (pageIndex > _pagemap.GetMaxPageIndex())
{
throw new ArgumentException("Too large page index");
}
long pageAllocation = _pagemap.GetPageAllocation(pageIndex);
if (pageAllocation == -1)
{
throw new PageMapException("Page is removed");
}
CheckRemovalMarker(pageIndex);
// prevent ThreadAbortException while vacuuming
try { }
finally
{
_pagemap.MarkPageAsFree(pageIndex);
if (_pagemap.GetEmptyPageCount() > _maxEmptyPages)
{
Vacuum();
}
else
{
_pagemap.Flush();
}
}
}
}
finally
{
Unlock();
}
}
public void CorrectlyApplyDeleteRecord()
{
long deleteIndex;
using (var fileSystemPageManager = new FileSystemPageManager(4096))
using (var storage = new Storage(fileSystemPageManager))
{
storage.OpenOrCreate(StoragePath);
deleteIndex = fileSystemPageManager.CreatePage().Index;
}
using (var fileSystemPageManager = new FileSystemPageManager(4096))
using (var storage = new Storage(fileSystemPageManager))
{
storage.OpenOrCreate(StoragePath);
Assert.True(fileSystemPageManager.PageExists(deleteIndex));
}
string fileName;
using (var fileSystemPageManager = new FileSystemPageManager(4096))
using (var storage = new Storage(fileSystemPageManager))
using (var recoveryFile = new RecoveryFile(fileSystemPageManager, fileSystemPageManager.PageSize))
{
storage.OpenOrCreate(StoragePath);
fileSystemPageManager.Dispose();
recoveryFile.WriteDeletePageRecord(deleteIndex);
recoveryFile.WriteFinalMarker();
fileName = recoveryFile.FileName;
}
Assert.True(File.Exists(fileName));
Assert.GreaterOrEqual(new FileInfo(fileName).Length, 1);
using (var manager = new FileSystemPageManager(4096))
using (var storage = new Storage(manager))
{
storage.OpenOrCreate(StoragePath);
Assert.False(manager.PageExists(deleteIndex));
Assert.AreEqual(deleteIndex, manager.CreatePage().Index);
}
}
public void CorrectlyRecoverResurrectedPage()
{
long index;
long resurrectIndex;
using (var fileSystemPageManager = new FileSystemPageManager(4096))
using (var storage = new Storage(fileSystemPageManager))
{
storage.OpenOrCreate(StoragePath);
var page = fileSystemPageManager.CreatePage();
index = page.Index;
}
using (var fileSystemPageManager = new FileSystemPageManager(4096))
using (var storage = new Storage(fileSystemPageManager))
{
storage.OpenOrCreate(StoragePath);
var page = fileSystemPageManager.FetchPage(index);
Assert.AreEqual(index, page.Index);
Assert.AreNotEqual(0xff, page.Content[10]);
}
string fileName;
using (var fileSystemPageManager = new FileSystemPageManager(4096))
using (var storage = new Storage(fileSystemPageManager))
using (var recoveryFile = new RecoveryFile(fileSystemPageManager, fileSystemPageManager.PageSize))
{
storage.OpenOrCreate(StoragePath);
var page = fileSystemPageManager.FetchPage(index);
index = page.Index;
page.Content[10] = 0xaf;
fileSystemPageManager.RemovePage(index);
var resurrectedPage = fileSystemPageManager.CreatePage();
resurrectIndex = resurrectedPage.Index;
//check we're not going wrong way
Assert.AreEqual(index, resurrectIndex);
resurrectedPage.Content[10] = 0xff;
Assert.AreNotEqual(0xff, page.Content[10]);
fileSystemPageManager.Dispose();
recoveryFile.WriteUpdatePageRecord(page);
recoveryFile.WriteDeletePageRecord(index);
recoveryFile.WriteUpdatePageRecord(resurrectedPage);
recoveryFile.WriteFinalMarker();
fileName = recoveryFile.FileName;
}
Assert.True(File.Exists(fileName));
Assert.GreaterOrEqual(new FileInfo(fileName).Length, 1);
using (var manager = new FileSystemPageManager(4096))
using (var storage = new Storage(manager))
{
storage.OpenOrCreate(StoragePath);
var page = manager.FetchPage(index);
Assert.AreEqual(resurrectIndex, page.Index);
Assert.AreEqual(0xff, page.Content[10]);
}
}
