/// <summary>
/// Reads the list of page table items whose head is stored at the page index provided.
/// The data read from persistent storage is merges with the data already in memory
/// using the following protocol:
/// if the in memory data has the "IsDirty" flag set then we keep the in memory data
/// else we over-write the in-memory data with the data from disk
/// </summary>
/// <param name="stream">data file to read from</param>
/// <param name="pageIdx">index of the first physical page storing the list</param>
/// <returns>returns the index of the first physical page we read data from</returns>
public int ReadPageTableData(FileStreamWrapper stream, int pageIdx)
{
List <PageTableItem> itemList = null;
List <int> pageIdxList = null;
// create reader
ListReader <PageTableItem> reader = new ListReader <PageTableItem>();
reader.ReadList(stream, pageIdx, out itemList, out pageIdxList);
// merge with current data
for (int idx = 0; idx < this.pageTable.Count && idx < itemList.Count; idx++)
{
if (!this.pageTable[idx].IsDirty)
{
this.pageTable[idx] = itemList[idx];
}
}
// add the missing ones
if (this.pageTable.Count < itemList.Count)
{
this.pageTable.AddRange(
itemList.GetRange(
this.pageTable.Count,
(itemList.Count - this.pageTable.Count)));
}
// update page index
this.pageTableStoragePages = pageIdxList;
// return index of the first page
return(this.pageTableStoragePages[0]);
}
/// <summary>
/// Reads the list of index items whose head is stored at the page index provided.
/// The data read from persistent storage is merges with the data already in memory
/// using the following protocol:
/// if the in memory data has the "IsDirty" flag set then we keep the in memory data
/// else we over-write the in-memory data with the data from disk
/// </summary>
/// <param name="stream">data file to read from</param>
/// <param name="pageIdx">index of the first physical page storing the list</param>
/// <returns>returns the index of the first physical page we read data from</returns>
public int ReadIndexData(FileStreamWrapper stream, int pageIdx)
{
List <IndexItem <T> > itemList = null;
List <int> pageIdxList = null;
// create reader
ListReader <IndexItem <T> > reader = new ListReader <IndexItem <T> >();
reader.ReadList(stream, pageIdx, out itemList, out pageIdxList);
// merge with current data
for (int idx = 0; idx < itemList.Count; idx++)
{
var item = itemList[idx];
IndexItem <T> indexEntry = null;
if (this.indexMap.TryGetValue(item.ResourceId, out indexEntry))
{
if (null == indexEntry ||
indexEntry.IsDirty)
{
continue;
}
}
this.indexMap[item.ResourceId] = item;
}
// update page index
this.indexStoragePages = pageIdxList;
// return index of the first page
return(this.indexStoragePages[0]);
}
/// <summary>
/// Reads the list of data items whose head is stored at the page index provided.
/// </summary>
/// <param name="stream">data file to read from</param>
/// <param name="pageIdx">index of the first physical page storing the list</param>
/// <returns>returns the index of the first physical page we read data from</returns>
public int ReadPageManagerData(FileStreamWrapper stream, int pageIdx)
{
List <int> itemList = null;
List <int> pageIdxList = null;
// create reader
ListReader <int> reader = new ListReader <int>();
reader.ReadList(stream, pageIdx, out itemList, out pageIdxList);
// merge with current data
this.SetFreePages(itemList);
// update page index
this.managerStoragePages = pageIdxList;
return(this.managerStoragePages[0]);
}
/// <summary>
/// Reads the list of data items whose head is stored at the page index provided.
/// </summary>
/// <param name="stream">data file to read from</param>
/// <param name="pageIdx">index of the first physical page storing the list</param>
/// <returns>returns the index of the first physical page we read data from</returns>
public int ReadTransactionTableData(FileStreamWrapper stream, int pageIdx)
{
List<TransItem> itemList = null;
List<int> pageIdxList = null;
// create reader
ListReader<TransItem> reader = new ListReader<TransItem>();
reader.ReadList(stream, pageIdx, out itemList, out pageIdxList);
// clear the current data
this.contextTable.Clear();
foreach (TransItem item in itemList)
{
this.contextTable.Add(item.Transaction, item);
}
// update page index
this.contextTableStoragePages = pageIdxList;
// return index of the first page
return this.contextTableStoragePages[0];
}
/// <summary>
/// Reads the list of data items whose head is stored at the page index provided.
/// </summary>
/// <param name="stream">data file to read from</param>
/// <param name="pageIdx">index of the first physical page storing the list</param>
/// <returns>returns the index of the first physical page we read data from</returns>
public int ReadTransactionTableData(FileStreamWrapper stream, int pageIdx)
{
List <TransItem> itemList = null;
List <int> pageIdxList = null;
// create reader
ListReader <TransItem> reader = new ListReader <TransItem>();
reader.ReadList(stream, pageIdx, out itemList, out pageIdxList);
// clear the current data
this.contextTable.Clear();
foreach (TransItem item in itemList)
{
this.contextTable.Add(item.Transaction, item);
}
// update page index
this.contextTableStoragePages = pageIdxList;
// return index of the first page
return(this.contextTableStoragePages[0]);
}
/// <summary>
/// Reads the list of data items whose head is stored at the page index provided.
/// </summary>
/// <param name="stream">data file to read from</param>
/// <param name="pageIdx">index of the first physical page storing the list</param>
/// <returns>returns the index of the first physical page we read data from</returns>
public int ReadPageManagerData(FileStreamWrapper stream, int pageIdx)
{
List<int> itemList = null;
List<int> pageIdxList = null;
// create reader
ListReader<int> reader = new ListReader<int>();
reader.ReadList(stream, pageIdx, out itemList, out pageIdxList);
// merge with current data
this.SetFreePages(itemList);
// update page index
this.managerStoragePages = pageIdxList;
return this.managerStoragePages[0];
}
/// <summary>
/// Reads the list of page table items whose head is stored at the page index provided.
/// The data read from persistent storage is merges with the data already in memory
/// using the following protocol:
/// if the in memory data has the "IsDirty" flag set then we keep the in memory data
/// else we over-write the in-memory data with the data from disk
/// </summary>
/// <param name="stream">data file to read from</param>
/// <param name="pageIdx">index of the first physical page storing the list</param>
/// <returns>returns the index of the first physical page we read data from</returns>
public int ReadPageTableData(FileStreamWrapper stream, int pageIdx)
{
List<PageTableItem> itemList = null;
List<int> pageIdxList = null;
// create reader
ListReader<PageTableItem> reader = new ListReader<PageTableItem>();
reader.ReadList(stream, pageIdx, out itemList, out pageIdxList);
// merge with current data
for (int idx = 0; idx < this.pageTable.Count && idx < itemList.Count; idx++)
{
if (!this.pageTable[idx].IsDirty)
{
this.pageTable[idx] = itemList[idx];
}
}
// add the missing ones
if (this.pageTable.Count < itemList.Count)
{
this.pageTable.AddRange(
itemList.GetRange(
this.pageTable.Count,
(itemList.Count - this.pageTable.Count)));
}
// update page index
this.pageTableStoragePages = pageIdxList;
// return index of the first page
return this.pageTableStoragePages[0];
}
private StorageContext ReadStorageContext(TransItem contextData, out List <int> oldStorageContextPages)
{
// allocate the storage page list
oldStorageContextPages = new List <int>();
// look for the context in the map
StorageContext storageContext = new StorageContext();
// read in the page table
if (TransItem.NotStored != contextData.PageTableStartPage)
{
storageContext.PageTable.ReadPageTableData(
this.dataFile, contextData.PageTableStartPage);
oldStorageContextPages.AddRange(
storageContext.PageTable.GetStoragePages());
}
// read in the resource index
if (TransItem.NotStored != contextData.ResourceIndexStartPage)
{
storageContext.ResourceIndex.ReadIndexData(
this.dataFile, contextData.ResourceIndexStartPage);
oldStorageContextPages.AddRange(
storageContext.ResourceIndex.GetStoragePages());
}
// read in the reservation index
if (TransItem.NotStored != contextData.ReservationIndexStartPage)
{
storageContext.ReservationIndex.ReadIndexData(
this.dataFile, contextData.ReservationIndexStartPage);
oldStorageContextPages.AddRange(
storageContext.ReservationIndex.GetStoragePages());
}
// read in the allocated page list
if (TransItem.NotStored != contextData.AllocatedPageListStartPage)
{
List <int> usedPages = null;
List <int> data = null;
ListReader <int> reader = new ListReader <int>();
reader.ReadList(this.dataFile, contextData.AllocatedPageListStartPage, out data, out usedPages);
storageContext.AllocatedPageList = data;
oldStorageContextPages.AddRange(usedPages);
}
// read in the freed page list
if (TransItem.NotStored != contextData.FreedPageListStartPage)
{
List <int> usedPages = null;
List <int> data = null;
ListReader <int> reader = new ListReader <int>();
reader.ReadList(this.dataFile, contextData.FreedPageListStartPage, out data, out usedPages);
storageContext.FreedPageList = data;
oldStorageContextPages.AddRange(usedPages);
}
return(storageContext);
}
