private void WriteDBRoot(DBHdr dbRoot)
{
StoragePage rootPage = new StoragePage();
rootPage.AddRecord(dbRoot);
rootPage.WritePageData(this.dataFile, RootPage);
}
// reads a page from persistent storage
private void aReadPageData(StoragePage page, int pageIndex)
{
lock (ManagerLock)
{
page.ReadPageData(this.dataFile, pageIndex);
}
}
// reads a resource or a reservation data item
protected virtual bool Read <I, R>(Transaction context, StorageContext storageContext, StorageIndex <I> index, I rID, bool lockPage, out R data)
{
// look for the resource in the index
IndexItem <I> address = index.GetResourceAddress(rID);
if (null == address)
{
data = default(R);
return(false);
}
if (lockPage)
{
// Aquire a lock on the logical page address to ensure that the page is not
// being written while we read the data
this.LockPage(context, MyLM.LockMode.Read, address.Page);
}
// find the physical page
int fileAddress = storageContext.PageTable.GetPhysicalPage(address.Page);
// get the page
StoragePage page = new StoragePage();
this.aReadPageData(page, fileAddress);
// read the data
data = (R)page.ReadRecord(address.Record);
return(true);
}
public object ReadRecord(int recordIdx)
{
if (recordIdx >= this.recordList.Count ||
0 > recordIdx)
{
throw new InvalidRecordException();
}
object data = StoragePage.Deserialize(
this.recordList[recordIdx]);
return(data);
}
private DBHdr ReadDBRoot()
{
DBHdr dbRoot = null;
try
{
StoragePage rootPage = new StoragePage();
rootPage.ReadPageData(this.dataFile, RootPage);
dbRoot = (DBHdr)rootPage.ReadRecord(0);
}
catch (Exception)
{
dbRoot = null;
}
return(dbRoot);
}
public void WriteRecord(int recordIdx, object data)
{
if (recordIdx >= this.recordList.Count ||
0 > recordIdx)
{
throw new InvalidRecordException();
}
// encode the data
//byte[] record = RecordDataEncoder.GetBytes(data);
byte[] record = StoragePage.Serialize(data);
if (0 > this.GetAvailableSpace() + this.GetRecordSize(recordIdx) - this.GetRecordSize(record))
{
throw new InsuffcientSpaceException();
}
this.recordList[recordIdx] = record;
}
// writes a page to persistent storage and does book-keeping for allocated and freed pages
private int aWritePageData(StoragePage page, StorageContext storageContext, int fileAddress)
{
lock (ManagerLock)
{
// store the index of the current page
if (0 <= fileAddress)
{
storageContext.FreedPageList.Add(fileAddress);
}
// write the page
fileAddress = page.WritePageData(
this.dataFile, this.pageManager.GetFreePage());
// store the index of the page we just wrote to
storageContext.AllocatedPageList.Add(fileAddress);
return(fileAddress);
}
}
public int AddRecord(object data)
{
byte[] record = StoragePage.Serialize(data);
if (0 > this.GetAvailableSpace() - this.GetRecordSize(record))
{
throw new InsuffcientSpaceException();
}
// lets find a space to insert this data
int index = this.recordList.IndexOf(null);
if (-1 == index)
{
index = this.recordList.Count;
}
// add the data
this.recordList.Insert(index, record);
// return to index
return(this.recordList.IndexOf(record));
}
public void SP_TestAddRecord()
{
TestData[] testList =
{
new TestData{ data = "test data 1", recordIdx = 0},
new TestData{ data = "test data 2", recordIdx = 1},
};
StoragePage page = new StoragePage();
AddRecords(page, testList);
// test adding a record when page is full
string masterRecord = "1234567890";
int maxCount =
(StoragePage_Accessor.PageSize - sizeof(int))
/ (sizeof(int) + StoragePage_Accessor.Serialize(masterRecord).Length);
List<TestData> noSpacetestList = new List<TestData>();
for(int idx = 0; idx < maxCount; idx++)
{
TestData record = new TestData
{
data = masterRecord,
recordIdx = idx,
};
noSpacetestList.Add(record);
}
noSpacetestList.Add(new TestData
{
data = masterRecord,
exception = "InsuffcientSpaceException",
});
StoragePage page2 = new StoragePage();
AddRecords(page2, noSpacetestList.ToArray());
}
private void WriteRecords(StoragePage page, TestData[] data)
{
foreach (TestData test in data)
{
try
{
page.WriteRecord(test.recordIdx, test.data);
}
catch (Exception e)
{
Assert.AreEqual(test.exception, e.GetType().Name,
"Unexpected exception. Test Data = [{0}]", test.ToString());
}
}
}
private void ReadRecords(StoragePage page, TestData[] data)
{
foreach (TestData test in data)
{
try
{
string result = (string)page.ReadRecord(test.recordIdx);
Assert.AreEqual(test.data, result,
"Read record did not match. Test Data = [{0}]", test.ToString());
}
catch (Exception e)
{
Assert.AreEqual(test.exception, e.GetType().Name,
"Unexpected exception. Test Data = [{0}]", test.ToString());
}
}
}
private void AddRecords(StoragePage page, TestData[] data)
{
foreach (TestData test in data)
{
try
{
int result = page.AddRecord(test.data);
Assert.AreEqual(test.recordIdx, result,
string.Format("Return value did not match. Test Data=[{0}]", test.ToString()));
}
catch (Exception e)
{
Assert.AreEqual(test.exception, e.GetType().Name,
"Unexpected exception. Test Data = [{0}]", test.ToString());
}
}
}
public void SP_TestReadWriteRecord()
{
TestData[] addList =
{
new TestData{data = "Record0", recordIdx = 0},
new TestData{data = "Record1", recordIdx = 1},
};
TestData[] readAddList = addList;
TestData[] readWriteTestList =
{
new TestData{data = "Record-1", recordIdx = -1, exception = "InvalidRecordException"},
new TestData{data = "RecordMax", recordIdx = int.MaxValue, exception = "InvalidRecordException"},
new TestData{data = "RecordLen", recordIdx = addList.Length, exception = "InvalidRecordException"},
new TestData{data = "Record0_2", recordIdx = addList[0].recordIdx},
new TestData{data = "Record1_2", recordIdx = addList[1].recordIdx},
};
TestData[] readWriteList = readWriteTestList;
StoragePage page = new StoragePage();
// setup the page by adding some records and
// verify by reading the records back
AddRecords(page, addList);
ReadRecords(page, readAddList);
// execute writes
WriteRecords(page, readWriteTestList);
ReadRecords(page, readWriteList);
}
public void SP_TestReadWritePage()
{
string dataFile = "SP_TestData1.tpdb";
if (File.Exists(dataFile))
{
File.Delete(dataFile);
}
TestData[] pageData =
{
new TestData{data = "Record_0", recordIdx = 0},
new TestData{data = "Record_1", recordIdx = 1},
new TestData{data = "Record_2", recordIdx = 2}
};
int pageIndex = int.MinValue;
// write the page
using (FileStreamWrapper dataFileStream = FileStreamWrapper.CreateObject(dataFile))
{
// populate the page with some data
StoragePage page = new StoragePage();
AddRecords(page, pageData);
// write the file to disk
pageIndex = page.WritePageData(dataFileStream, -1);
}
// read the page
using (FileStreamWrapper dataFileStream = FileStreamWrapper.CreateObject(dataFile))
{
// read page from file
StoragePage page = new StoragePage();
page.ReadPageData(dataFileStream, pageIndex);
// validate the page data
ReadRecords(page, pageData);
}
}
public void SP_TestDeleteRecord()
{
TestData[] addList =
{
new TestData{ data = "Record0", recordIdx = 0 }
};
TestData[] deleteTestList =
{
new TestData{ recordIdx = -1, exception = "InvalidRecordException"},
new TestData{ recordIdx = 2, exception = "InvalidRecordException"},
new TestData{ recordIdx = 0, exception = ""},
new TestData{ recordIdx = 0, exception = "InvalidRecordException"},
};
StoragePage page = new StoragePage();
AddRecords(page, addList);
DeleteRecords(page, deleteTestList);
}
// writes a resource or reservation data item
protected virtual bool Write <I, R>(Transaction context, StorageContext storageContext, StorageIndex <I> index, I rID, R data)
{
// look for the resource in the index
IndexItem <I> address = index.GetResourceAddress(rID);
if (null == address &&
null == data)
{
// nothing to do:
// user probably wanted to delete an non-existing item
return(true);
}
else if (null == address &&
null != data)
{
address = new IndexItem <I>
{
Page = storageContext.PageTable.GetLastLogicalPage(),
Record = -1
};
}
// Aquire a lock on the logical page address to ensure that we have access to the page
this.LockPage(context, MyLM.LockMode.Write, address.Page);
// find the physical page
int fileAddress = storageContext.PageTable.GetPhysicalPage(address.Page);
// get the page
StoragePage page = new StoragePage();
if (0 <= fileAddress)
{
this.aReadPageData(page, fileAddress);
}
// write the record
while (true)
{
try
{
if (0 > address.Record)
{
address.Record = page.AddRecord(data);
}
else
{
page.WriteRecord(address.Record, data);
}
}
catch (StoragePage.InsuffcientSpaceException)
{
// did not fit on last page so allocate a new page
page = new StoragePage();
address.Page = -1;
fileAddress = -1;
continue;
}
break;
}
// write the page
fileAddress = this.aWritePageData(page, storageContext, fileAddress);
// update the page table
if (0 > address.Page)
{
address.Page = storageContext.PageTable.SetLogicalPage(fileAddress);
}
else
{
storageContext.PageTable.UpdatePage(address.Page, fileAddress);
}
// update the index
if (null == data)
{
// handle deletes
address = null;
}
index.SetResourceAddress(rID, address);
return(true);
}
