public bool Start()
{
lock (lockObject) {
treeSystem = new StoreTreeSystem(store, branchNodeSize, leafNodeSize, heapNodeCacheSize, branchNodeCacheSize);
treeSystem.Create();
treeSystem.CheckPoint();
// The actual database
StoreTreeSystem treeStore;
// Get the header area
IArea headerArea = store.GetArea(-1);
int magicValue = headerArea.ReadInt4();
// If header area magic value is zero, then we assume this is a brand
// new database and initialize it with the configuration information
// given.
if (magicValue == 0)
{
// Create a tree store inside the file store,
treeStore = new StoreTreeSystem(store, branchNodeSize, leafNodeSize, heapNodeCacheSize,
branchNodeCacheSize);
// Create the tree and returns a pointer to the tree,
long treePointer = treeStore.Create();
// Create an area object with state information about the tree
IAreaWriter awriter = store.CreateArea(128);
awriter.WriteInt4(0x0101); // The version value
awriter.WriteInt8(treePointer);
awriter.WriteInt4(branchNodeSize);
awriter.WriteInt4(leafNodeSize);
awriter.Finish();
long dummy = awriter.Id;
IMutableArea harea = store.GetMutableArea(-1);
harea.WriteInt4(0x092BA001); // The magic value
harea.WriteInt8(awriter.Id);
harea.CheckOut();
}
else if (magicValue == 0x092BA001)
{
long apointer = headerArea.ReadInt8();
// The area that contains configuration details,
IArea initArea = store.GetArea(apointer);
int version = initArea.ReadInt4();
if (version != 0x0101)
{
throw new IOException("Unknown version in tree initialization area");
}
// Read the pointer to the tree store
long treePointer = initArea.ReadInt8();
// Read the branch and leaf node sizes as set when the database was
// created.
int ibranchNodeSize = initArea.ReadInt4();
int ileafNodeSize = initArea.ReadInt4();
// Create the tree store
treeStore = new StoreTreeSystem(store, ibranchNodeSize, ileafNodeSize, heapNodeCacheSize,
branchNodeCacheSize);
// Initialize the tree
treeStore.Init(treePointer);
}
else
{
throw new IOException("Data is corrupt, invalid magic value in store");
}
// Set the point of the tree store
treeStore.CheckPoint();
// Set up final internal state and return true
treeSystem = treeStore;
databaseStarted = true;
return(true);
}
}
