void Shrink(Delegate_deleteFile procDeleteFile)
{
List <string> keys = new List <string>();
List <PageItem> items = new List <PageItem>();
foreach (string key in _pageTable.Keys)
{
PageItem item = _pageTable[key];
if (item.State == "OK")
{
keys.Add(key);
}
}
if (keys.Count > 0)
{
foreach (string key in keys)
{
_pageTable.Remove(key);
}
foreach (PageItem item in items)
{
if (procDeleteFile != null)
{
procDeleteFile(item.FilePath);
}
else
{
item.Delete();
}
}
}
}
// 清除已经失效的 PageItem
// parameters:
// delta 闲置多少时间以上才清理
public void Clean(bool bLock,
TimeSpan delta,
Delegate_deleteFile procDeleteFile,
CancellationToken token)
{
List <string> keys = new List <string>();
List <PageItem> items = new List <PageItem>();
if (bLock)
{
_lock.EnterReadLock();
}
try
{
DateTime now = DateTime.Now;
foreach (string key in _pageTable.Keys)
{
token.ThrowIfCancellationRequested();
PageItem item = _pageTable[key];
if (item.State == "OK" &&
now - item.LastUse > delta)
{
keys.Add(key);
items.Add(item);
}
}
}
finally
{
if (bLock)
{
_lock.ExitReadLock();
}
}
if (keys.Count > 0)
{
if (bLock)
{
_lock.EnterWriteLock();
}
try
{
foreach (string key in keys)
{
token.ThrowIfCancellationRequested();
_pageTable.Remove(key);
}
}
finally
{
if (bLock)
{
_lock.ExitWriteLock();
}
}
foreach (PageItem item in items)
{
token.ThrowIfCancellationRequested();
if (procDeleteFile != null)
{
procDeleteFile(item.FilePath);
}
else
{
item.Delete();
}
}
}
}