public CachedIndexOutput(ICloudProvider CloudProvider, Directory CacheDirectory, string Name)
{
this.cloudProvider = CloudProvider;
this.cacheDirectory = CacheDirectory;
this.name = Name;
this.fileMutex = BlobMutexManager.GrabMutex(this.name);
this.fileMutex.WaitOne();
try {
// create the local cache one we will operate against...
this.indexOutput = this.cacheDirectory.CreateOutput(this.name);
} finally {
this.fileMutex.ReleaseMutex();
}
}
// ctor for clone
private CachedIndexInput(CachedIndexInput cloneInput)
{
this.name = cloneInput.name;
this.fileMutex = BlobMutexManager.GrabMutex(this.name);
this.fileMutex.WaitOne();
try {
#if FULLDEBUG
Debug.WriteLine("Creating clone for " + this.name);
#endif
this.indexInput = cloneInput.indexInput.Clone() as IndexInput;
// FRAGILE: ASSUME: File is already downloaded and current
} catch (Exception) {
// sometimes we get access denied on the 2nd stream...but not always. I haven't tracked it down yet but this covers our tail until I do
Debug.WriteLine("Dagnabbit, falling back to memory clone for " + this.name);
} finally {
this.fileMutex.ReleaseMutex();
}
}
public CachedIndexInput(ICloudProvider CloudProvider, Directory CacheDirectory, string Name)
{
this.name = Name;
#if FULLDEBUG
Debug.WriteLine("Opening " + this.name);
#endif
this.fileMutex = BlobMutexManager.GrabMutex(this.name);
this.fileMutex.WaitOne();
try {
bool fFileNeeded = false;
FileMetadata cloudMetadata = CloudProvider.FileMetadata(this.name);
if (!cloudMetadata.Exists)
{
fFileNeeded = false;
// TODO: Delete local if it doesn't exist on cloud?
/*
* if (CacheDirectory.FileExists(this.name)) {
* CacheDirectory.DeleteFile(this.name);
* }
*/
}
else if (!CacheDirectory.FileExists(this.name))
{
fFileNeeded = true;
}
else
{
long cachedLength = CacheDirectory.FileLength(this.name);
long blobLength = cloudMetadata.Length;
DateTime blobLastModifiedUTC = cloudMetadata.LastModified.ToUniversalTime();
if (!cloudMetadata.Exists || cachedLength != blobLength)
{
fFileNeeded = true;
}
else
{
// there seems to be an error of 1 tick which happens every once in a while
// for now we will say that if they are within 1 tick of each other and same length
DateTime cachedLastModifiedUTC = new DateTime(CacheDirectory.FileModified(this.name), DateTimeKind.Local).ToUniversalTime();
if (cachedLastModifiedUTC < blobLastModifiedUTC)
{
TimeSpan timeSpan = blobLastModifiedUTC.Subtract(cachedLastModifiedUTC);
if (timeSpan.TotalSeconds > 1)
{
fFileNeeded = true;
}
else
{
#if FULLDEBUG
Debug.WriteLine("Using cache for " + this.name + ": " + timeSpan.TotalSeconds);
#endif
// file not needed
}
}
}
}
// if the file does not exist
// or if it exists and it is older then the lastmodified time in the blobproperties (which always comes from the blob storage)
if (fFileNeeded)
{
using (StreamOutput fileStream = new StreamOutput(CacheDirectory.CreateOutput(this.name))) {
Stream blobStream = CloudProvider.Download(this.name);
blobStream.CopyTo(fileStream);
fileStream.Flush();
Debug.WriteLine("GET {0} RETREIVED {1} bytes", this.name, fileStream.Length);
}
}
else
{
#if FULLDEBUG
if (!cloudMetadata.Exists)
{
Debug.WriteLine("Cloud doesn't have " + this.name);
}
else
{
Debug.WriteLine("Using cached file for " + this.name);
}
#endif
}
// open the file in read only mode
this.indexInput = CacheDirectory.OpenInput(this.name);
} finally {
this.fileMutex.ReleaseMutex();
}
}
