/// <summary>
/// 新增缓存数据
/// </summary>
public void Put(string key, Entry entry)
{
lock (this)
{
PruneIfNeeded(entry.Data.Length);
var file = GetFileForKey(key);
try
{
var fos = file.Open(FileMode.OpenOrCreate);
CacheHeader e = new CacheHeader(key, entry);
bool success = e.WriteHeader(fos);
if (!success)
{
fos.Close();
VolleyLog.D("Failed to write header for {0}", file.FullName);
throw new IOException();
}
fos.Write(entry.Data, 0, entry.Data.Length);
fos.Close();
PutEntry(key, e);
return;
}
catch (IOException) { }
file.Delete();
if (File.Exists(file.FullName))
{
VolleyLog.D("Could not clean up file {0}", file.FullName);
}
}
}
private void RemoveEntry(String key)
{
CacheHeader entry = null;
mEntries.TryGetValue(key, out entry);
if (entry != null)
{
mTotalSize -= entry.Size;
mEntries.Remove(key);
}
}
/// <summary>
/// 初始化缓存
/// </summary>
public void Initialize()
{
lock (this)
{
if (!mRootDirectory.Exists)
{
mRootDirectory.Create();
if (!mRootDirectory.Exists)
{
VolleyLog.E("Unable to create cache dir {0}", mRootDirectory.FullName);
}
return;
}
//获取已缓存文件并添加到缓存表中
FileInfo[] files = mRootDirectory.GetFiles();
if (files == null)
{
return;
}
foreach (FileInfo file in files)
{
FileStream fs = null;
try
{
fs = file.Open(FileMode.OpenOrCreate);
CacheHeader entry = CacheHeader.ReadHeader(fs);
entry.Size = fs.Length;
PutEntry(entry.Key, entry);
}
catch (IOException)
{
if (file != null)
{
file.Delete();
}
}
finally
{
try
{
if (fs != null)
{
fs.Close();
}
}
catch (IOException) { }
}
}
}
}
/// <summary>
/// 当需要的空间大于指定空间后清除部分缓存
/// </summary>
private void PruneIfNeeded(int neededSpace)
{
if (mTotalSize + neededSpace < mMaxCacheSizeInBytes)
{
return;
}
if (VolleyLog.DEBUG)
{
VolleyLog.V("Pruning old cache entries.");
}
long before = mTotalSize;
int prunedFiles = 0;
long startTime = SystemClock.ElapsedRealtime();
Dictionary <string, CacheHeader> delDic = new Dictionary <string, CacheHeader>();
foreach (KeyValuePair <String, CacheHeader> pair in mEntries)
{
CacheHeader e = pair.Value;
var fi = GetFileForKey(e.Key);
fi.Delete();
if (!File.Exists(fi.FullName))
{
mTotalSize -= e.Size;
}
else
{
VolleyLog.D("Could not delete cache entry for key={0},filename={1}", e.Key, GetFilenameForKey(e.Key));
}
prunedFiles++;
delDic.Add(pair.Key, pair.Value);
if (mTotalSize + neededSpace < mMaxCacheSizeInBytes * HYSTERESIS_FACTOR)
{
break;
}
}
foreach (KeyValuePair <string, CacheHeader> del in delDic)
{
mEntries.Remove(del.Key);
}
if (VolleyLog.DEBUG)
{
VolleyLog.V("Pruned {0} files,{1} bytes,{2} ms", prunedFiles, (mTotalSize - before), SystemClock.ElapsedRealtime() - startTime);
}
}
private void PutEntry(String key, CacheHeader entry)
{
if (!mEntries.ContainsKey(key))
{
mTotalSize += entry.Size;
}
else
{
CacheHeader oldEntry = mEntries[key];
mTotalSize += (entry.Size - oldEntry.Size);
}
if (mEntries.ContainsKey(key))
{
mEntries[key] = entry;
}
else
{
mEntries.Add(key, entry);
}
}
/// <summary>
/// 从流中读取缓存相关信息
/// （当前只提供文件缓存所以是从文件中读取）
/// </summary>
public static CacheHeader ReadHeader(Stream input)
{
CacheHeader entry = new CacheHeader();
int magic = DiskBasedCache.ReadInt(input);
if (magic != DiskBasedCache.CACHE_MAGIC)
{
throw new IOException();
}
entry.Key = DiskBasedCache.ReadString(input);
entry.ETag = DiskBasedCache.ReadString(input);
if (String.IsNullOrEmpty(entry.ETag))
{
entry.ETag = null;
}
entry.ServerDate = DiskBasedCache.ReadLong(input);
entry.LastModified = DiskBasedCache.ReadLong(input);
entry.Ttl = DiskBasedCache.ReadLong(input);
entry.SoftTtl = DiskBasedCache.ReadLong(input);
entry.ResponseHeaders = DiskBasedCache.ReadStringStringMap(input);
return(entry);
}
/// <summary>
/// 获取缓存数据
/// </summary>
public Entry Get(string key)
{
lock (this)
{
CacheHeader entry = null;
mEntries.TryGetValue(key, out entry);
if (entry == null)
{
return(null);
}
FileInfo file = GetFileForKey(key);
FileStream fs = null;
try
{
fs = file.Open(FileMode.OpenOrCreate);
CacheHeader.ReadHeader(fs);
byte[] data = StreamToBytes(fs, (int)(fs.Length - fs.Position));
return(entry.ToCacheEntry(data));
}
catch (IOException e)
{
VolleyLog.D("{0}:{1}", file.FullName, e.ToString());
}
finally
{
if (fs != null)
{
try
{
fs.Close();
}
catch (IOException) { }
}
}
return(null);
}
}
private void PutEntry(String key, CacheHeader entry)
{
if (!mEntries.ContainsKey(key))
{
mTotalSize += entry.Size;
}
else
{
CacheHeader oldEntry = mEntries[key];
mTotalSize += (entry.Size - oldEntry.Size);
}
if (mEntries.ContainsKey(key))
{
mEntries[key] = entry;
}
else
{
mEntries.Add(key, entry);
}
}
/// <summary>
/// ������������
/// </summary>
public void Put(string key, Entry entry)
{
lock (this)
{
PruneIfNeeded(entry.Data.Length);
var file = GetFileForKey(key);
try
{
var fos = file.Open(FileMode.OpenOrCreate);
CacheHeader e = new CacheHeader(key, entry);
bool success = e.WriteHeader(fos);
if (!success)
{
fos.Close();
VolleyLog.D("Failed to write header for {0}", file.FullName);
throw new IOException();
}
fos.Write(entry.Data, 0, entry.Data.Length);
fos.Close();
PutEntry(key, e);
return;
}
catch (IOException) { }
file.Delete();
if (File.Exists(file.FullName))
{
VolleyLog.D("Could not clean up file {0}", file.FullName);
}
}
}
/// <summary>
/// �����ж�ȡ���������Ϣ
/// ����ǰֻ�ṩ�ļ����������Ǵ��ļ��ж�ȡ��
/// </summary>
public static CacheHeader ReadHeader(Stream input)
{
CacheHeader entry = new CacheHeader();
int magic = DiskBasedCache.ReadInt(input);
if (magic != DiskBasedCache.CACHE_MAGIC)
{
throw new IOException();
}
entry.Key = DiskBasedCache.ReadString(input);
entry.ETag = DiskBasedCache.ReadString(input);
if (String.IsNullOrEmpty(entry.ETag))
{
entry.ETag = null;
}
entry.ServerDate = DiskBasedCache.ReadLong(input);
entry.LastModified = DiskBasedCache.ReadLong(input);
entry.Ttl = DiskBasedCache.ReadLong(input);
entry.SoftTtl = DiskBasedCache.ReadLong(input);
entry.ResponseHeaders = DiskBasedCache.ReadStringStringMap(input);
return entry;
}
