/// <summary>
/// Put a new request in the queue. Returns a DataRequestDescriptor matching the request. If there is
/// already a request pending for the same source, the existing descriptor is returned.
/// </summary>
/// <param name="request"></param>
/// <returns></returns>
static public DataRequest Request(DataRequestDescriptor request)
{
// TODO: actually parse the request and differentiate between different DataRequest types
DataRequestHTTP drd = new DataRequestHTTP(request);
// before anything, try to fulfill the request from cache
#if VERBOSE
Log.Write(Log.Levels.Verbose, "DataStore: New request for " + request.Source);
#endif
/*
* if (drd.TryCache())
* {
#if VERBOSE
* Log.Write(Log.Levels.Verbose, "DataStore: Request fulfilled from cache, no queue required");
#endif
* if (drd.RequestDescriptor.CompletionCallback != null)
* {
#if VERBOSE
* Log.Write(Log.Levels.Verbose, "DataStore: calling completion callback...");
#endif
* drd.RequestDescriptor.CompletionCallback(drd);
* }
* return drd;
* }
*/
lock (m_lock)
{
#if VERBOSE
Log.Write(Log.Levels.Verbose, "DataStore: Request enqueued.");
#endif
m_pendingRequests.Insert(0, drd);
}
return(drd);
}
public DataRequest(DataRequestDescriptor request)
{
m_lock = new Object();
m_request = request;
m_contentStream = null;
m_state = DataRequestState.Queued;
m_cacheHit = false;
m_headers = new NameValueCollection();
m_priority = 50;
m_totalRequests++;
m_nextTry = DateTime.Now;
}
static private Stream CacheCallback(DataRequestDescriptor drd)
{
lock (m_cacheLock)
{
// search for any files that could be used to fulfill the request.
if (drd.CacheLocation == null)
{
return(null);
}
// Try cache with default file extension
string cacheFullPath = drd.CacheLocation;
if (File.Exists(cacheFullPath))
{
return(new FileStream(cacheFullPath, FileMode.Open));
}
// Try cache but accept any valid image file extension
const string ValidExtensions = ".bmp.dds.dib.hdr.jpg.jpeg.pfm.png.ppm.tga.gif.tif";
// if (allowCache)
{
string cacheSearchPath = Path.GetDirectoryName(cacheFullPath);
if (Directory.Exists(cacheSearchPath))
{
foreach (string imageFile in Directory.GetFiles(
cacheSearchPath,
Path.GetFileNameWithoutExtension(cacheFullPath) + ".*"))
{
string extension = Path.GetExtension(imageFile).ToLower();
if (ValidExtensions.IndexOf(extension) > 0)
{
return(new FileStream(imageFile, FileMode.Open));
}
}
}
}
// no stream found for this data request.
return(null);
}
}
public TextureSource(string url, string cacheLocation, ImageStore imageStore, PriorityCallback priorityCallback)
{
// if (s_inQueueTexture == null)
// InitStaticTextures();
// convert cache location to dds
// string ddsCache = Path.GetDirectoryName(cacheLocation)+"\\"+Path.GetFileNameWithoutExtension(cacheLocation) + ".dds";
m_drd = new DataRequestDescriptor(url, cacheLocation, new CacheCallback(CacheCallback));
m_drd.CompletionCallback = new CompletionCallback(CompletionCallback);
m_drd.PriorityCallback = priorityCallback;
m_imageStore = imageStore;
if (m_settings == null)
{
// get the World Wind Settings through reflection.
Assembly a = Assembly.GetEntryAssembly();
Type appType = a.GetType("WorldWind.MainApplication");
System.Reflection.FieldInfo finfo = appType.GetField("Settings", BindingFlags.Static | BindingFlags.Public | BindingFlags.GetField);
m_settings = finfo.GetValue(null) as WorldWindSettings;
}
}
public DataRequestHTTP(DataRequestDescriptor request)
: base(request)
{
}