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/* code for loading in @font-face defined font data */

#ifndef nsFontFaceLoader_h_
#define nsFontFaceLoader_h_

#include "nsCOMPtr.h"
#include "nsIStreamLoader.h"
#include "nsIURI.h"
#include "nsIChannel.h"
#include "gfxUserFontSet.h"
#include "nsHashKeys.h"
#include "nsTHashtable.h"

class nsIRequest;
class nsISupports;
class nsPresContext;
class nsIPrincipal;

class nsFontFaceLoader;

// nsUserFontSet - defines the loading mechanism for downloadable fonts
class nsUserFontSet : public gfxUserFontSet
{
public:
  nsUserFontSet(nsPresContext *aContext);
  ~nsUserFontSet();

  // Called when this font set is no longer associated with a presentation.
  void Destroy();

  // starts loading process, creating and initializing a nsFontFaceLoader obj
  // returns whether load process successfully started or not
  nsresult StartLoad(gfxFontEntry *aFontToLoad, 
                     const gfxFontFaceSrc *aFontFaceSrc);

  // Called by nsFontFaceLoader when the loader has completed normally.
  // It's removed from the mLoaders set.
  void RemoveLoader(nsFontFaceLoader *aLoader);

  nsPresContext *GetPresContext() { return mPresContext; }

protected:
  nsPresContext *mPresContext;  // weak reference

  // Set of all loaders pointing to us. These are not strong pointers,
  // but that's OK because nsFontFaceLoader always calls RemoveLoader on
  // us before it dies (unless we die first).
  nsTHashtable< nsPtrHashKey<nsFontFaceLoader> > mLoaders;
};

class nsFontFaceLoader : public nsIStreamLoaderObserver
{
public:

  nsFontFaceLoader(gfxFontEntry *aFontToLoad, nsIURI *aFontURI, 
                   nsUserFontSet *aFontSet, nsIChannel *aChannel);
  virtual ~nsFontFaceLoader();

  NS_DECL_ISUPPORTS
  NS_DECL_NSISTREAMLOADEROBSERVER 

  // initiate the load
  nsresult Init();
  // cancel the load and remove its reference to mFontSet
  void Cancel();

  void DropChannel() { mChannel = nsnull; }

  static nsresult CheckLoadAllowed(nsIPrincipal* aSourcePrincipal,
                                   nsIURI* aTargetURI,
                                   nsISupports* aContext);

private:
  nsRefPtr<gfxFontEntry>  mFontEntry;
  nsCOMPtr<nsIURI>        mFontURI;
  nsRefPtr<nsUserFontSet> mFontSet;
  nsCOMPtr<nsIChannel>    mChannel;
};

#endif /* !defined(nsFontFaceLoader_h_) */