gecko-dev/layout/style/FontFace.h

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_dom_FontFace_h
#define mozilla_dom_FontFace_h

#include "mozilla/dom/FontFaceBinding.h"
#include "gfxUserFontSet.h"
#include "nsCSSProperty.h"
#include "nsCSSValue.h"
#include "nsWrapperCache.h"

class gfxFontFaceBufferSource;
class nsCSSFontFaceRule;
class nsPresContext;

namespace mozilla {
struct CSSFontFaceDescriptors;
namespace dom {
class FontFaceBufferSource;
struct FontFaceDescriptors;
class FontFaceSet;
class FontFaceInitializer;
class FontFaceStatusSetter;
class Promise;
class StringOrArrayBufferOrArrayBufferView;
}
}

namespace mozilla {
namespace dom {

class FontFace MOZ_FINAL : public nsISupports,
                           public nsWrapperCache
{
  friend class mozilla::dom::FontFaceBufferSource;
  friend class mozilla::dom::FontFaceInitializer;
  friend class mozilla::dom::FontFaceStatusSetter;
  friend class Entry;

public:
  class Entry MOZ_FINAL : public gfxUserFontEntry {
    friend class FontFace;

  public:
    Entry(gfxUserFontSet* aFontSet,
          const nsTArray<gfxFontFaceSrc>& aFontFaceSrcList,
          uint32_t aWeight,
          int32_t aStretch,
          uint32_t aItalicStyle,
          const nsTArray<gfxFontFeature>& aFeatureSettings,
          uint32_t aLanguageOverride,
          gfxSparseBitSet* aUnicodeRanges)
      : gfxUserFontEntry(aFontSet, aFontFaceSrcList, aWeight, aStretch,
                         aItalicStyle, aFeatureSettings, aLanguageOverride,
                         aUnicodeRanges) {}

    virtual void SetLoadState(UserFontLoadState aLoadState) MOZ_OVERRIDE;

  protected:
    // The FontFace objects that use this user font entry.  We need to store
    // an array of these, not just a single pointer, since the user font
    // cache can return the same entry for different FontFaces that have
    // the same descriptor values and come from the same origin.
    nsAutoTArray<FontFace*,1> mFontFaces;
  };

  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(FontFace)

  nsISupports* GetParentObject() const { return mParent; }
  virtual JSObject* WrapObject(JSContext* aCx) MOZ_OVERRIDE;

  static already_AddRefed<FontFace>
  CreateForRule(nsISupports* aGlobal, nsPresContext* aPresContext,
                nsCSSFontFaceRule* aRule);

  nsCSSFontFaceRule* GetRule() { return mRule; }

  void GetDesc(nsCSSFontDesc aDescID, nsCSSValue& aResult) const;

  gfxUserFontEntry* GetUserFontEntry() const { return mUserFontEntry; }
  void SetUserFontEntry(gfxUserFontEntry* aEntry);

  /**
   * Returns whether this object is in a FontFaceSet.
   */
  bool IsInFontFaceSet() { return mInFontFaceSet; }

  /**
   * Sets whether this object is in a FontFaceSet.  This is called by the
   * FontFaceSet when Add, Remove, etc. are called.
   */
  void SetIsInFontFaceSet(bool aInFontFaceSet) {
    MOZ_ASSERT(!(!aInFontFaceSet && HasRule()),
               "use DisconnectFromRule instead");
    mInFontFaceSet = aInFontFaceSet;
  }

  /**
   * Returns whether this FontFace is initialized.  A rule backed
   * FontFace is considered initialized at construction time.  For
   * FontFace objects created using the FontFace JS constructor, it
   * is once all the descriptors have been parsed.
   */
  bool IsInitialized() const { return mInitialized; }

  FontFaceSet* GetFontFaceSet() const { return mFontFaceSet; }

  /**
   * Gets the family name of the FontFace as a raw string (such as 'Times', as
   * opposed to GetFamily, which returns a CSS-escaped string, such as
   * '"Times"').  Returns whether a valid family name was available.
   */
  bool GetFamilyName(nsString& aResult);

  /**
   * Returns whether this object is CSS-connected, i.e. reflecting an
   * @font-face rule.
   */
  bool HasRule() const { return mRule; }

  /**
   * Breaks the connection between this FontFace and its @font-face rule.
   */
  void DisconnectFromRule();

  /**
   * Returns whether there is an ArrayBuffer or ArrayBufferView of font
   * data.
   */
  bool HasFontData() const;

  /**
   * Creates a gfxFontFaceBufferSource to represent the font data
   * in this object.
   */
  already_AddRefed<gfxFontFaceBufferSource> CreateBufferSource();

  /**
   * Gets a pointer to and the length of the font data stored in the
   * ArrayBuffer or ArrayBufferView.
   */
  bool GetData(uint8_t*& aBuffer, uint32_t& aLength);

  // Web IDL
  static already_AddRefed<FontFace>
  Constructor(const GlobalObject& aGlobal,
              const nsAString& aFamily,
              const mozilla::dom::StringOrArrayBufferOrArrayBufferView& aSource,
              const mozilla::dom::FontFaceDescriptors& aDescriptors,
              ErrorResult& aRV);

  void GetFamily(nsString& aResult);
  void SetFamily(const nsAString& aValue, mozilla::ErrorResult& aRv);
  void GetStyle(nsString& aResult);
  void SetStyle(const nsAString& aValue, mozilla::ErrorResult& aRv);
  void GetWeight(nsString& aResult);
  void SetWeight(const nsAString& aValue, mozilla::ErrorResult& aRv);
  void GetStretch(nsString& aResult);
  void SetStretch(const nsAString& aValue, mozilla::ErrorResult& aRv);
  void GetUnicodeRange(nsString& aResult);
  void SetUnicodeRange(const nsAString& aValue, mozilla::ErrorResult& aRv);
  void GetVariant(nsString& aResult);
  void SetVariant(const nsAString& aValue, mozilla::ErrorResult& aRv);
  void GetFeatureSettings(nsString& aResult);
  void SetFeatureSettings(const nsAString& aValue, mozilla::ErrorResult& aRv);

  mozilla::dom::FontFaceLoadStatus Status();
  mozilla::dom::Promise* Load(mozilla::ErrorResult& aRv);
  mozilla::dom::Promise* GetLoaded(mozilla::ErrorResult& aRv);

private:
  FontFace(nsISupports* aParent, nsPresContext* aPresContext);
  ~FontFace();

  /**
   * Initializes the source and descriptors on this object based on values that
   * were passed in to the JS constructor.  If the source was specified as
   * an ArrayBuffer or ArrayBufferView, parsing of the font data in there
   * will be started.
   */
  void Initialize(FontFaceInitializer* aInitializer);

  // Helper function for Load.
  void DoLoad();

  /**
   * Parses a @font-face descriptor value, storing the result in aResult.
   * Returns whether the parsing was successful.
   */
  bool ParseDescriptor(nsCSSFontDesc aDescID, const nsAString& aString,
                       nsCSSValue& aResult);

  // Helper function for the descriptor setter methods.
  void SetDescriptor(nsCSSFontDesc aFontDesc,
                     const nsAString& aValue,
                     mozilla::ErrorResult& aRv);

  /**
   * Sets all of the descriptor values in mDescriptors using values passed
   * to the JS constructor.
   */
  bool SetDescriptors(const nsAString& aFamily,
                      const FontFaceDescriptors& aDescriptors);

  /**
   * Marks the FontFace as initialized and informs the FontFaceSet it is in,
   * if any.
   */
  void OnInitialized();

  /**
   * Sets the current loading status.
   */
  void SetStatus(mozilla::dom::FontFaceLoadStatus aStatus);

  void GetDesc(nsCSSFontDesc aDescID,
               nsCSSProperty aPropID,
               nsString& aResult) const;

  /**
   * Returns and takes ownership of the buffer storing the font data.
   */
  void TakeBuffer(uint8_t*& aBuffer, uint32_t& aLength);

  nsCOMPtr<nsISupports> mParent;
  nsPresContext* mPresContext;

  // A Promise that is fulfilled once the font represented by this FontFace
  // is loaded, and is rejected if the load fails.
  nsRefPtr<mozilla::dom::Promise> mLoaded;

  // The @font-face rule this FontFace object is reflecting, if it is a
  // rule backed FontFace.
  nsRefPtr<nsCSSFontFaceRule> mRule;

  // The FontFace object's user font entry.  This is initially null, but is set
  // during FontFaceSet::UpdateRules and when a FontFace is explicitly loaded.
  nsRefPtr<Entry> mUserFontEntry;

  // The current load status of the font represented by this FontFace.
  // Note that we can't just reflect the value of the gfxUserFontEntry's
  // status, since the spec sometimes requires us to go through the event
  // loop before updating the status, rather than doing it immediately.
  mozilla::dom::FontFaceLoadStatus mStatus;

  // Represents where a FontFace's data is coming from.
  enum SourceType {
    eSourceType_FontFaceRule = 1,
    eSourceType_URLs,
    eSourceType_Buffer
  };

  // Where the font data for this FontFace is coming from.
  SourceType mSourceType;

  // If the FontFace was constructed with an ArrayBuffer(View), this is a
  // copy of the data from it.
  uint8_t* mSourceBuffer;
  uint32_t mSourceBufferLength;

  // The values corresponding to the font face descriptors, if we are not
  // a rule backed FontFace object.  For rule backed objects, we use
  // the descriptors stored in mRule.
  nsAutoPtr<mozilla::CSSFontFaceDescriptors> mDescriptors;

  // The FontFaceSet this FontFace is associated with, regardless of whether
  // it is currently "in" the set.
  nsRefPtr<FontFaceSet> mFontFaceSet;

  // Whether this FontFace appears in the FontFaceSet.
  bool mInFontFaceSet;

  // Whether the FontFace has been fully initialized.  This takes at least one
  // run around the event loop, as the parsing of the src descriptor is done
  // off an event queue task.
  bool mInitialized;

  // Records whether Load() was called on this FontFace before it was
  // initialized.  When the FontFace eventually does become initialized,
  // mLoadPending is checked and Load() is called if needed.
  bool mLoadWhenInitialized;
};

} // namespace dom
} // namespace mozilla

#endif // !defined(mozilla_dom_FontFace_h)