/// <summary>
/// Gets the device unique ID, or uses the fallback if none is available due to application configuration.
/// </summary>
/// <returns>
/// The discovered device identifier.
/// </returns>
public virtual string GetDeviceUniqueId()
{
if (this.deviceId != null)
{
return(this.deviceId);
}
object uniqueId;
if (DeviceExtendedProperties.TryGetValue("DeviceUniqueId", out uniqueId) == true)
{
byte[] result = (byte[])uniqueId;
using (SHA256 hasher = new SHA256Managed())
{
return(this.deviceId = Convert.ToBase64String(hasher.ComputeHash(result)));
}
}
FallbackDeviceContext fallbackContext = this.FallbackContext;
return(this.deviceId = fallbackContext.DeviceUniqueId);
}
/// <summary>
/// Reads the serialized context from persistent storage, or will create a new context if none exits.
/// </summary>
/// <returns>The fallback context we will be using.</returns>
private FallbackDeviceContext ReadSerializedContext()
{
// if we already have a context, just return that
if (this.cachedContext != null)
{
return(this.cachedContext);
}
// if we don't aquire the sync root and check again, in case we were waiting before
lock (this.syncRoot)
{
if (this.cachedContext != null)
{
return(this.cachedContext);
}
FallbackDeviceContext temp = ReadSerializedContext(DeviceService.ContextPersistentStorageFileName);
Thread.MemoryBarrier();
this.cachedContext = temp;
}
return(this.cachedContext);
}
/// <summary>
/// Reads the serialized context from persistent storage, or will create a new context if none exits.
/// </summary>
/// <param name="fileName">The file to read from storage.</param>
/// <returns>The fallback context we will be using.</returns>
private static FallbackDeviceContext ReadSerializedContext(string fileName)
{
// get a reference to the persitent store
using (IsolatedStorageFile persistentStore = IsolatedStorageFile.GetUserStoreForApplication())
{
// if the file exits, attempt to read/deserialize it. If we fail, we'll just regen it.
bool regenerateContext = true;
if (persistentStore.FileExists(fileName) == true)
{
try
{
using (IsolatedStorageFileStream stream = persistentStore.OpenFile(fileName, FileMode.Open, FileAccess.Read))
{
XDocument document = XDocument.Load(stream);
FallbackDeviceContext temp = new FallbackDeviceContext();
if (temp.Deserialize(document.Root) == true)
{
regenerateContext = false;
return temp;
}
}
}
catch (IsolatedStorageException)
{
// TODO: swallow?
}
catch (FileNotFoundException)
{
// TODO: swallow?
}
catch (XmlException)
{
// TODO: swallow?
}
}
// if we're here we will need to regen our context
if (regenerateContext == true)
{
// create the XML document first
XDocument document = new XDocument();
document.Add(new XElement(XName.Get(typeof(FallbackDeviceContext).Name)));
// initialize the new set of settings and serialize to the document root
FallbackDeviceContext temp = new FallbackDeviceContext();
temp.Initialize();
temp.Serialize(document.Root);
// write to persistent storage
try
{
using (IsolatedStorageFileStream stream = persistentStore.OpenFile(fileName, FileMode.OpenOrCreate, FileAccess.Write))
{
stream.SetLength(0);
document.Save(stream);
stream.Flush(true);
return temp;
}
}
catch (IsolatedStorageException)
{
// TODO: swallow?
}
catch (FileNotFoundException)
{
// TODO: swallow?
}
}
}
FallbackDeviceContext defaultReturn = new FallbackDeviceContext();
defaultReturn.Initialize();
return defaultReturn;
}
/// <summary>
/// Reads the serialized context from persistent storage, or will create a new context if none exits.
/// </summary>
/// <returns>The fallback context we will be using.</returns>
private FallbackDeviceContext ReadSerializedContext()
{
// if we already have a context, just return that
if (this.cachedContext != null)
{
return this.cachedContext;
}
// if we don't aquire the sync root and check again, in case we were waiting before
lock (this.syncRoot)
{
if (this.cachedContext != null)
{
return this.cachedContext;
}
FallbackDeviceContext temp = ReadSerializedContext(DeviceService.ContextPersistentStorageFileName);
Thread.MemoryBarrier();
this.cachedContext = temp;
}
return this.cachedContext;
}
/// <summary>
/// Reads the serialized context from persistent storage, or will create a new context if none exits.
/// </summary>
/// <param name="fileName">The file to read from storage.</param>
/// <returns>The fallback context we will be using.</returns>
private static FallbackDeviceContext ReadSerializedContext(string fileName)
{
// get a reference to the persitent store
using (IsolatedStorageFile persistentStore = IsolatedStorageFile.GetUserStoreForApplication())
{
// if the file exits, attempt to read/deserialize it. If we fail, we'll just regen it.
bool regenerateContext = true;
if (persistentStore.FileExists(fileName) == true)
{
try
{
using (IsolatedStorageFileStream stream = persistentStore.OpenFile(fileName, FileMode.Open, FileAccess.Read))
{
XDocument document = XDocument.Load(stream);
FallbackDeviceContext temp = new FallbackDeviceContext();
if (temp.Deserialize(document.Root) == true)
{
regenerateContext = false;
return(temp);
}
}
}
catch (IsolatedStorageException)
{
// TODO: swallow?
}
catch (FileNotFoundException)
{
// TODO: swallow?
}
catch (XmlException)
{
// TODO: swallow?
}
}
// if we're here we will need to regen our context
if (regenerateContext == true)
{
// create the XML document first
XDocument document = new XDocument();
document.Add(new XElement(XName.Get(typeof(FallbackDeviceContext).Name)));
// initialize the new set of settings and serialize to the document root
FallbackDeviceContext temp = new FallbackDeviceContext();
temp.Initialize();
temp.Serialize(document.Root);
// write to persistent storage
try
{
using (IsolatedStorageFileStream stream = persistentStore.OpenFile(fileName, FileMode.OpenOrCreate, FileAccess.Write))
{
stream.SetLength(0);
document.Save(stream);
stream.Flush(true);
return(temp);
}
}
catch (IsolatedStorageException)
{
// TODO: swallow?
}
catch (FileNotFoundException)
{
// TODO: swallow?
}
}
}
FallbackDeviceContext defaultReturn = new FallbackDeviceContext();
defaultReturn.Initialize();
return(defaultReturn);
}
