public ClassEntry Search(uint cid)
{
//time consuming operations, that's the reason for cache
if (m_cid_cache.ContainsKey(cid))
{
ClassEntry t = (ClassEntry)m_cid_cache[cid];
t.BreakLinks();
t.BuildLinks(m_LRU, m_LRU.Next);
return(t);
}
else
{
//do the sequential search, :(
OOD.Imp.Storage.BTree.BTEnumerator bt = m_tree.GetEnumerator();
while (bt.MoveNext())
{
KCatalog key = (KCatalog)bt.Current;
Debug.Assert(key != null);
if (key.ClassInfo != null && key.ClassInfo.CId == cid)
{
//found
_put_in_cache(cid, key.ClassName, key.ClassInfo.FieldNames, key.ClassInfo.TopNodeSId);
return((ClassEntry)m_cid_cache[cid]);
}
}
return(null);
}
}
public void BreakLinks()
{
this.m_prev.m_next = this.m_next;
this.m_next.m_prev = this.m_prev;
this.m_prev = this.m_next = this;
}
public void BreakLinks()
{
this.m_prev.m_next = this.m_next;
this.m_next.m_prev = this.m_prev;
this.m_prev = this.m_next = this;
}
public ClassEntry Search(string className)
{
if (m_name_cache.ContainsKey(className))
{
ClassEntry result = (ClassEntry)m_name_cache[className];
result.BreakLinks();
result.BuildLinks(m_LRU, m_LRU.Next);
return(result);
}
else
{
//not in cache, get it from disk
KCatalog target = new KCatalog(className);
KCatalog t = (KCatalog)m_tree.Search(target);
if (t != null)
{
_put_in_cache(t.ClassInfo.CId, className, t.ClassInfo.FieldNames, t.ClassInfo.TopNodeSId);
return((ClassEntry)m_cid_cache[t.ClassInfo.CId]);
}
else
{
return(null);
}
}
}
public void BuildLinks(ClassEntry prev, ClassEntry next)
{
this.m_next = next;
this.m_prev = prev;
prev.m_next = this;
next.m_prev = this;
}
private ClassEntry m_LRU; //maintain the least recently used list for cached class info
public CatalogTree(uint topNodeSId, SegmentManager sgManager, uint nextCId)
{
m_tree = new BTree(topNodeSId, sgManager, new KCatalog());
m_next_cid = nextCId;
m_cid_cache = new Hashtable(m_cache_limit);
m_name_cache = new Hashtable(m_cache_limit);
m_LRU = new ClassEntry();
}
public void BuildLinks(ClassEntry prev, ClassEntry next)
{
this.m_next = next;
this.m_prev = prev;
prev.m_next = this;
next.m_prev = this;
}
private ClassEntry m_LRU; //maintain the least recently used list for cached class info
public CatalogTree(uint topNodeSId, SegmentManager sgManager, uint nextCId)
{
m_tree = new BTree(topNodeSId, sgManager, new KCatalog());
m_next_cid = nextCId;
m_cid_cache = new Hashtable(m_cache_limit);
m_name_cache = new Hashtable(m_cache_limit);
m_LRU = new ClassEntry();
}
public bool Delete(string className)
{
//remove it from cache if needed
if (m_name_cache.ContainsKey(className))
{
ClassEntry t = (ClassEntry)m_name_cache[className];
t.BreakLinks();
m_name_cache.Remove(className);
m_cid_cache.Remove(t.CId);
}
return(m_tree.Delete(new KCatalog(className)));
}
internal void _put_in_cache(uint cid, string className, string[] fields, uint topNodeSId)
{
Debug.Assert(m_name_cache.Count == m_cid_cache.Count);
if (m_name_cache.Count > m_cache_limit)
{
//kick one out needed
ClassEntry victim = m_LRU.Previous;
Debug.Assert(victim != null);
victim.BreakLinks(); //remove from LRU list
m_name_cache.Remove(victim.ClassName);
m_cid_cache.Remove(victim.CId);
}
ClassEntry ce = new ClassEntry(cid, className, fields, topNodeSId);
m_name_cache.Add(className, ce);
m_cid_cache.Add(cid, ce);
ce.BuildLinks(m_LRU, m_LRU.Next); //put it to the front of the list, -- most recently used
}
public bool UpdateTopNodeSId(string className, uint newTopNodeSId)
{
ClassEntry oldValue = Search(className);
if (oldValue != null)
{
//update cache
((ClassEntry)m_cid_cache[oldValue.CId]).SetTopNodeSId(newTopNodeSId);
//update the b-tree file
KCatalog newKey = new KCatalog(className);
newKey.ClassInfo = new DCatalog(oldValue.CId, oldValue.FieldNames, newTopNodeSId);
if (m_tree.UpdateData(newKey) == false)
{
throw new OOD.Exception.ProgramLogicError(
this,
"Update operation failed for class info b-tree.");
}
return(true);
}
else
{
return(false);
}
}
public ClassEntry()
{
m_prev = m_next = this;
}
public ClassEntry(uint cid, string className, string[] fields, uint topNodeSId)
: base(cid, className, fields, topNodeSId)
{
m_prev = m_next = this;
}
public ClassEntry()
{
m_prev = m_next = this;
}
public ClassEntry(uint cid, string className, string[] fields, uint topNodeSId)
:base(cid, className, fields, topNodeSId)
{
m_prev = m_next = this;
}
internal void _put_in_cache(uint cid, string className, string[] fields, uint topNodeSId)
{
Debug.Assert(m_name_cache.Count == m_cid_cache.Count);
if (m_name_cache.Count > m_cache_limit)
{
//kick one out needed
ClassEntry victim = m_LRU.Previous;
Debug.Assert(victim != null);
victim.BreakLinks(); //remove from LRU list
m_name_cache.Remove(victim.ClassName);
m_cid_cache.Remove(victim.CId);
}
ClassEntry ce = new ClassEntry(cid, className, fields, topNodeSId);
m_name_cache.Add(className, ce);
m_cid_cache.Add(cid, ce);
ce.BuildLinks(m_LRU, m_LRU.Next); //put it to the front of the list, -- most recently used
}
