DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Implementation

Mercurial (72ee4800d415)

VCS Links

AutoTable

FontTableHashEntry

GlobalFontMatch

ScriptRange

gfxCharacterMap

gfxFontEntry

gfxFontFamily

Macros

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822
/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * 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 GFX_FONTENTRY_H
#define GFX_FONTENTRY_H

#include "gfxTypes.h"
#include "nsString.h"
#include "gfxFontConstants.h"
#include "gfxFontFeatures.h"
#include "gfxFontUtils.h"
#include "nsTArray.h"
#include "nsTHashtable.h"
#include "mozilla/HashFunctions.h"
#include "mozilla/MemoryReporting.h"
#include "MainThreadUtils.h"
#include "nsUnicodeScriptCodes.h"
#include "nsDataHashtable.h"
#include "harfbuzz/hb.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/WeakPtr.h"

typedef struct gr_face gr_face;

#ifdef DEBUG
#include <stdio.h>
#endif

struct gfxFontStyle;
class gfxContext;
class gfxFont;
class gfxFontFamily;
class gfxUserFontData;
class gfxSVGGlyphs;
class FontInfoData;
struct FontListSizes;
class nsAtom;

namespace mozilla {
class SVGContextPaint;
};

class gfxCharacterMap : public gfxSparseBitSet {
public:
    nsrefcnt AddRef() {
        NS_PRECONDITION(int32_t(mRefCnt) >= 0, "illegal refcnt");
        ++mRefCnt;
        NS_LOG_ADDREF(this, mRefCnt, "gfxCharacterMap", sizeof(*this));
        return mRefCnt;
    }

    nsrefcnt Release() {
        NS_PRECONDITION(0 != mRefCnt, "dup release");
        --mRefCnt;
        NS_LOG_RELEASE(this, mRefCnt, "gfxCharacterMap");
        if (mRefCnt == 0) {
            NotifyReleased();
            // |this| has been deleted.
            return 0;
        }
        return mRefCnt;
    }

    gfxCharacterMap() :
        mHash(0), mBuildOnTheFly(false), mShared(false)
    { }

    explicit gfxCharacterMap(const gfxSparseBitSet& aOther) :
        gfxSparseBitSet(aOther),
        mHash(0), mBuildOnTheFly(false), mShared(false)
    { }

    void CalcHash() { mHash = GetChecksum(); }

    size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const {
        return gfxSparseBitSet::SizeOfExcludingThis(aMallocSizeOf);
    }

    // hash of the cmap bitvector
    uint32_t mHash;

    // if cmap is built on the fly it's never shared
    bool mBuildOnTheFly;

    // cmap is shared globally
    bool mShared;

protected:
    void NotifyReleased();

    nsAutoRefCnt mRefCnt;

private:
    gfxCharacterMap(const gfxCharacterMap&);
    gfxCharacterMap& operator=(const gfxCharacterMap&);
};

class gfxFontEntry {
public:
    typedef mozilla::gfx::DrawTarget DrawTarget;
    typedef mozilla::unicode::Script Script;

    // Used by stylo
    NS_INLINE_DECL_THREADSAFE_REFCOUNTING(gfxFontEntry)

    explicit gfxFontEntry(const nsAString& aName, bool aIsStandardFace = false);

    // Create a new entry that refers to the same font as this, but without
    // additional state that may have been set up (such as family name).
    // (This is only to be used for system fonts in the platform font list,
    // not user fonts.)
    virtual gfxFontEntry* Clone() const = 0;

    // unique name for the face, *not* the family; not necessarily the
    // "real" or user-friendly name, may be an internal identifier
    const nsString& Name() const { return mName; }

    // family name
    const nsString& FamilyName() const { return mFamilyName; }

    // The following two methods may be relatively expensive, as they
    // will (usually, except on Linux) load and parse the 'name' table;
    // they are intended only for the font-inspection API, not for
    // perf-critical layout/drawing work.

    // The "real" name of the face, if available from the font resource;
    // returns Name() if nothing better is available.
    virtual nsString RealFaceName();

    uint16_t Weight() const { return mWeight; }
    int16_t Stretch() const { return mStretch; }

    bool IsUserFont() const { return mIsDataUserFont || mIsLocalUserFont; }
    bool IsLocalUserFont() const { return mIsLocalUserFont; }
    bool IsFixedPitch() const { return mFixedPitch; }
    bool IsItalic() const { return mStyle == NS_FONT_STYLE_ITALIC; }
    bool IsOblique() const { return mStyle == NS_FONT_STYLE_OBLIQUE; }
    bool IsUpright() const { return mStyle == NS_FONT_STYLE_NORMAL; }
    bool IsBold() const { return mWeight >= 600; } // bold == weights 600 and above
    bool IgnoreGDEF() const { return mIgnoreGDEF; }
    bool IgnoreGSUB() const { return mIgnoreGSUB; }

    // Return whether the face corresponds to "normal" CSS style properties:
    //    font-style: normal;
    //    font-weight: normal;
    //    font-stretch: normal;
    // If this is false, we might want to fall back to a different face and
    // possibly apply synthetic styling.
    bool IsNormalStyle() const
    {
        return IsUpright() &&
               Weight() == NS_FONT_WEIGHT_NORMAL &&
               Stretch() == NS_FONT_STRETCH_NORMAL;
    }

    // whether a feature is supported by the font (limited to a small set
    // of features for which some form of fallback needs to be implemented)
    virtual bool SupportsOpenTypeFeature(Script aScript, uint32_t aFeatureTag);
    bool SupportsGraphiteFeature(uint32_t aFeatureTag);

    // returns a set containing all input glyph ids for a given feature
    const hb_set_t*
    InputsForOpenTypeFeature(Script aScript, uint32_t aFeatureTag);

    virtual bool HasFontTable(uint32_t aTableTag);

    inline bool HasGraphiteTables() {
        if (!mCheckedForGraphiteTables) {
            CheckForGraphiteTables();
            mCheckedForGraphiteTables = true;
        }
        return mHasGraphiteTables;
    }

    inline bool HasCmapTable() {
        if (!mCharacterMap) {
            ReadCMAP();
            NS_ASSERTION(mCharacterMap, "failed to initialize character map");
        }
        return mHasCmapTable;
    }

    inline bool HasCharacter(uint32_t ch) {
        if (mCharacterMap && mCharacterMap->test(ch)) {
            return true;
        }
        return TestCharacterMap(ch);
    }

    virtual bool SkipDuringSystemFallback() { return false; }
    nsresult InitializeUVSMap();
    uint16_t GetUVSGlyph(uint32_t aCh, uint32_t aVS);

    // All concrete gfxFontEntry subclasses (except gfxUserFontEntry) need
    // to override this, otherwise the font will never be used as it will
    // be considered to support no characters.
    // ReadCMAP() must *always* set the mCharacterMap pointer to a valid
    // gfxCharacterMap, even if empty, as other code assumes this pointer
    // can be safely dereferenced.
    virtual nsresult ReadCMAP(FontInfoData *aFontInfoData = nullptr);

    bool TryGetSVGData(gfxFont* aFont);
    bool HasSVGGlyph(uint32_t aGlyphId);
    bool GetSVGGlyphExtents(DrawTarget* aDrawTarget, uint32_t aGlyphId,
                            gfxRect *aResult);
    void RenderSVGGlyph(gfxContext *aContext, uint32_t aGlyphId,
                        mozilla::SVGContextPaint* aContextPaint);
    // Call this when glyph geometry or rendering has changed
    // (e.g. animated SVG glyphs)
    void NotifyGlyphsChanged();

    bool     TryGetColorGlyphs();
    bool     GetColorLayersInfo(uint32_t aGlyphId,
                                const mozilla::gfx::Color& aDefaultColor,
                                nsTArray<uint16_t>& layerGlyphs,
                                nsTArray<mozilla::gfx::Color>& layerColors);

    // Access to raw font table data (needed for Harfbuzz):
    // returns a pointer to data owned by the fontEntry or the OS,
    // which will remain valid until the blob is destroyed.
    // The data MUST be treated as read-only; we may be getting a
    // reference to a shared system font cache.
    //
    // The default implementation uses CopyFontTable to get the data
    // into a byte array, and maintains a cache of loaded tables.
    //
    // Subclasses should override this if they can provide more efficient
    // access than copying table data into our own buffers.
    //
    // Get blob that encapsulates a specific font table, or nullptr if
    // the table doesn't exist in the font.
    //
    // Caller is responsible to call hb_blob_destroy() on the returned blob
    // (if non-nullptr) when no longer required. For transient access to a
    // table, use of AutoTable (below) is generally preferred.
    virtual hb_blob_t *GetFontTable(uint32_t aTag);

    // Stack-based utility to return a specified table, automatically releasing
    // the blob when the AutoTable goes out of scope.
    class AutoTable {
    public:
        AutoTable(gfxFontEntry* aFontEntry, uint32_t aTag)
        {
            mBlob = aFontEntry->GetFontTable(aTag);
        }
        ~AutoTable() {
            if (mBlob) {
                hb_blob_destroy(mBlob);
            }
        }
        operator hb_blob_t*() const { return mBlob; }
    private:
        hb_blob_t* mBlob;
        // not implemented:
        AutoTable(const AutoTable&) = delete;
        AutoTable& operator=(const AutoTable&) = delete;
    };

    // Return a font instance for a particular style. This may be a newly-
    // created instance, or a font already in the global cache.
    // We can't return a UniquePtr here, because we may be returning a shared
    // cached instance; but we also don't return already_AddRefed, because
    // the caller may only need to use the font temporarily and doesn't need
    // a strong reference.
    gfxFont* FindOrMakeFont(const gfxFontStyle *aStyle,
                            bool aNeedsBold,
                            gfxCharacterMap* aUnicodeRangeMap = nullptr);

    // Get an existing font table cache entry in aBlob if it has been
    // registered, or return false if not.  Callers must call
    // hb_blob_destroy on aBlob if true is returned.
    //
    // Note that some gfxFont implementations may not call this at all,
    // if it is more efficient to get the table from the OS at that level.
    bool GetExistingFontTable(uint32_t aTag, hb_blob_t** aBlob);

    // Elements of aTable are transferred (not copied) to and returned in a
    // new hb_blob_t which is registered on the gfxFontEntry, but the initial
    // reference is owned by the caller.  Removing the last reference
    // unregisters the table from the font entry.
    //
    // Pass nullptr for aBuffer to indicate that the table is not present and
    // nullptr will be returned.  Also returns nullptr on OOM.
    hb_blob_t *ShareFontTableAndGetBlob(uint32_t aTag,
                                        nsTArray<uint8_t>* aTable);

    // Get the font's unitsPerEm from the 'head' table, in the case of an
    // sfnt resource. Will return kInvalidUPEM for non-sfnt fonts,
    // if present on the platform.
    uint16_t UnitsPerEm();
    enum {
        kMinUPEM = 16,    // Limits on valid unitsPerEm range, from the
        kMaxUPEM = 16384, // OpenType spec
        kInvalidUPEM = uint16_t(-1)
    };

    // Shaper face accessors:
    // NOTE that harfbuzz and graphite handle ownership/lifetime of the face
    // object in completely different ways.

    // Get HarfBuzz face corresponding to this font file.
    // Caller must release with hb_face_destroy() when finished with it,
    // and the font entry will be notified via ForgetHBFace.
    hb_face_t* GetHBFace();
    virtual void ForgetHBFace();

    // Get Graphite face corresponding to this font file.
    // Caller must call gfxFontEntry::ReleaseGrFace when finished with it.
    gr_face* GetGrFace();
    virtual void ReleaseGrFace(gr_face* aFace);

    // Does the font have graphite contextuals that involve the space glyph
    // (and therefore we should bypass the word cache)?
    bool HasGraphiteSpaceContextuals();

    // Release any SVG-glyphs document this font may have loaded.
    void DisconnectSVG();

    // Called to notify that aFont is being destroyed. Needed when we're tracking
    // the fonts belonging to this font entry.
    void NotifyFontDestroyed(gfxFont* aFont);

    // For memory reporting of the platform font list.
    virtual void AddSizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf,
                                        FontListSizes* aSizes) const;
    virtual void AddSizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf,
                                        FontListSizes* aSizes) const;

    // Used for reporting on individual font entries in the user font cache,
    // which are not present in the platform font list.
    size_t
    ComputedSizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;

    // Used when checking for complex script support, to mask off cmap ranges
    struct ScriptRange {
        uint32_t         rangeStart;
        uint32_t         rangeEnd;
        hb_tag_t         tags[3]; // one or two OpenType script tags to check,
                                  // plus a NULL terminator
    };

    bool SupportsScriptInGSUB(const hb_tag_t* aScriptTags);

    nsString         mName;
    nsString         mFamilyName;

    uint8_t          mStyle       : 2; // italic/oblique
    bool             mFixedPitch  : 1;
    bool             mIsBadUnderlineFont : 1;
    bool             mIsUserFontContainer : 1; // userfont entry
    bool             mIsDataUserFont : 1;      // platform font entry (data)
    bool             mIsLocalUserFont : 1;     // platform font entry (local)
    bool             mStandardFace : 1;
    bool             mIgnoreGDEF  : 1;
    bool             mIgnoreGSUB  : 1;
    bool             mSVGInitialized : 1;
    bool             mHasSpaceFeaturesInitialized : 1;
    bool             mHasSpaceFeatures : 1;
    bool             mHasSpaceFeaturesKerning : 1;
    bool             mHasSpaceFeaturesNonKerning : 1;
    bool             mSkipDefaultFeatureSpaceCheck : 1;
    bool             mGraphiteSpaceContextualsInitialized : 1;
    bool             mHasGraphiteSpaceContextuals : 1;
    bool             mSpaceGlyphIsInvisible : 1;
    bool             mSpaceGlyphIsInvisibleInitialized : 1;
    bool             mHasGraphiteTables : 1;
    bool             mCheckedForGraphiteTables : 1;
    bool             mHasCmapTable : 1;
    bool             mGrFaceInitialized : 1;
    bool             mCheckedForColorGlyph : 1;

    // bitvector of substitution space features per script, one each
    // for default and non-default features
    uint32_t         mDefaultSubSpaceFeatures[(int(Script::NUM_SCRIPT_CODES) + 31) / 32];
    uint32_t         mNonDefaultSubSpaceFeatures[(int(Script::NUM_SCRIPT_CODES) + 31) / 32];

    uint16_t         mWeight;
    int16_t          mStretch;

    RefPtr<gfxCharacterMap> mCharacterMap;
    uint32_t         mUVSOffset;
    mozilla::UniquePtr<uint8_t[]> mUVSData;
    mozilla::UniquePtr<gfxUserFontData> mUserFontData;
    mozilla::UniquePtr<gfxSVGGlyphs> mSVGGlyphs;
    // list of gfxFonts that are using SVG glyphs
    nsTArray<gfxFont*> mFontsUsingSVGGlyphs;
    nsTArray<gfxFontFeature> mFeatureSettings;
    mozilla::UniquePtr<nsDataHashtable<nsUint32HashKey,bool>> mSupportedFeatures;
    mozilla::UniquePtr<nsDataHashtable<nsUint32HashKey,hb_set_t*>> mFeatureInputs;
    uint32_t         mLanguageOverride;

    // Color Layer font support
    hb_blob_t*       mCOLR;
    hb_blob_t*       mCPAL;

protected:
    friend class gfxPlatformFontList;
    friend class gfxMacPlatformFontList;
    friend class gfxUserFcFontEntry;
    friend class gfxFontFamily;
    friend class gfxSingleFaceMacFontFamily;
    friend class gfxUserFontEntry;

    gfxFontEntry();

    // Protected destructor, to discourage deletion outside of Release():
    virtual ~gfxFontEntry();

    virtual gfxFont *CreateFontInstance(const gfxFontStyle *aFontStyle,
                                        bool aNeedsBold) = 0;

    virtual void CheckForGraphiteTables();

    // Copy a font table into aBuffer.
    // The caller will be responsible for ownership of the data.
    virtual nsresult CopyFontTable(uint32_t aTableTag,
                                   nsTArray<uint8_t>& aBuffer) {
        NS_NOTREACHED("forgot to override either GetFontTable or CopyFontTable?");
        return NS_ERROR_FAILURE;
    }

    // lookup the cmap in cached font data
    virtual already_AddRefed<gfxCharacterMap>
    GetCMAPFromFontInfo(FontInfoData *aFontInfoData,
                        uint32_t& aUVSOffset);

    // helper for HasCharacter(), which is what client code should call
    virtual bool TestCharacterMap(uint32_t aCh);

    // Font's unitsPerEm from the 'head' table, if available (will be set to
    // kInvalidUPEM for non-sfnt font formats)
    uint16_t mUnitsPerEm;

    // Shaper-specific face objects, shared by all instantiations of the same
    // physical font, regardless of size.
    // Usually, only one of these will actually be created for any given font
    // entry, depending on the font tables that are present.

    // hb_face_t is refcounted internally, so each shaper that's using it will
    // bump the ref count when it acquires the face, and "destroy" (release) it
    // in its destructor. The font entry has only this non-owning reference to
    // the face; when the face is deleted, it will tell the font entry to forget
    // it, so that a new face will be created next time it is needed.
    hb_face_t* mHBFace;

    static hb_blob_t* HBGetTable(hb_face_t *face, uint32_t aTag, void *aUserData);

    // Callback that the hb_face will use to tell us when it is being deleted.
    static void HBFaceDeletedCallback(void *aUserData);

    // gr_face is -not- refcounted, so it will be owned directly by the font
    // entry, and we'll keep a count of how many references we've handed out;
    // each shaper is responsible to call ReleaseGrFace on its entry when
    // finished with it, so that we know when it can be deleted.
    gr_face*   mGrFace;

    // hashtable to map raw table data ptr back to its owning blob, for use by
    // graphite table-release callback
    nsDataHashtable<nsPtrHashKey<const void>,void*>* mGrTableMap;

    // number of current users of this entry's mGrFace
    nsrefcnt mGrFaceRefCnt;

    static const void* GrGetTable(const void *aAppFaceHandle,
                                  unsigned int aName,
                                  size_t *aLen);
    static void GrReleaseTable(const void *aAppFaceHandle,
                               const void *aTableBuffer);

    // For memory reporting: size of user-font data belonging to this entry.
    // We record this in the font entry because the actual data block may be
    // handed over to platform APIs, so that it would become difficult (and
    // platform-specific) to measure it directly at report-gathering time.
    uint32_t mComputedSizeOfUserFont;

private:
    /**
     * Font table hashtable, to support GetFontTable for harfbuzz.
     *
     * The harfbuzz shaper (and potentially other clients) needs access to raw
     * font table data. This needs to be cached so that it can be used
     * repeatedly (each time we construct a text run; in some cases, for
     * each character/glyph within the run) without re-fetching large tables
     * every time.
     * 
     * Because we may instantiate many gfxFonts for the same physical font
     * file (at different sizes), we should ensure that they can share a
     * single cached copy of the font tables. To do this, we implement table
     * access and sharing on the fontEntry rather than the font itself.
     *
     * The default implementation uses GetFontTable() to read font table
     * data into byte arrays, and wraps them in blobs which are registered in
     * a hashtable.  The hashtable can then return pre-existing blobs to
     * harfbuzz.
     *
     * Harfbuzz will "destroy" the blobs when it is finished with them.  When
     * the last blob reference is removed, the FontTableBlobData user data
     * will remove the blob from the hashtable if still registered.
     */

    class FontTableBlobData;

    /**
     * FontTableHashEntry manages the entries of hb_blob_t's containing font
     * table data.
     *
     * This is used to share font tables across fonts with the same
     * font entry (but different sizes) for use by HarfBuzz.  The hashtable
     * does not own a strong reference to the blob, but keeps a weak pointer,
     * managed by FontTableBlobData.  Similarly FontTableBlobData keeps only a
     * weak pointer to the hashtable, managed by FontTableHashEntry.
     */

    class FontTableHashEntry : public nsUint32HashKey
    {
    public:
        // Declarations for nsTHashtable

        typedef nsUint32HashKey KeyClass;
        typedef KeyClass::KeyType KeyType;
        typedef KeyClass::KeyTypePointer KeyTypePointer;

        explicit FontTableHashEntry(KeyTypePointer aTag)
            : KeyClass(aTag)
            , mSharedBlobData(nullptr)
            , mBlob(nullptr)
        { }

        // NOTE: This assumes the new entry belongs to the same hashtable as
        // the old, because the mHashtable pointer in mSharedBlobData (if
        // present) will not be updated.
        FontTableHashEntry(FontTableHashEntry&& toMove)
            : KeyClass(mozilla::Move(toMove))
            , mSharedBlobData(mozilla::Move(toMove.mSharedBlobData))
            , mBlob(mozilla::Move(toMove.mBlob))
        {
            toMove.mSharedBlobData = nullptr;
            toMove.mBlob = nullptr;
        }

        ~FontTableHashEntry() { Clear(); }

        // FontTable/Blob API

        // Transfer (not copy) elements of aTable to a new hb_blob_t and
        // return ownership to the caller.  A weak reference to the blob is
        // recorded in the hashtable entry so that others may use the same
        // table.
        hb_blob_t *
        ShareTableAndGetBlob(nsTArray<uint8_t>&& aTable,
                             nsTHashtable<FontTableHashEntry> *aHashtable);

        // Return a strong reference to the blob.
        // Callers must hb_blob_destroy the returned blob.
        hb_blob_t *GetBlob() const;

        void Clear();

        size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;

    private:
        static void DeleteFontTableBlobData(void *aBlobData);
        // not implemented
        FontTableHashEntry& operator=(FontTableHashEntry& toCopy);

        FontTableBlobData *mSharedBlobData;
        hb_blob_t *mBlob;
    };

    mozilla::UniquePtr<nsTHashtable<FontTableHashEntry> > mFontTableCache;

    gfxFontEntry(const gfxFontEntry&);
    gfxFontEntry& operator=(const gfxFontEntry&);
};


// used when iterating over all fonts looking for a match for a given character
struct GlobalFontMatch {
    GlobalFontMatch(const uint32_t aCharacter,
                    const gfxFontStyle *aStyle) :
        mCh(aCharacter), mStyle(aStyle),
        mMatchRank(0), mCount(0), mCmapsTested(0)
        {

        }

    const uint32_t         mCh;          // codepoint to be matched
    const gfxFontStyle*    mStyle;       // style to match
    int32_t                mMatchRank;   // metric indicating closest match
    RefPtr<gfxFontEntry> mBestMatch;   // current best match
    RefPtr<gfxFontFamily> mMatchedFamily; // the family it belongs to
    uint32_t               mCount;       // number of fonts matched
    uint32_t               mCmapsTested; // number of cmaps tested
};

class gfxFontFamily {
public:
    // Used by stylo
    NS_INLINE_DECL_THREADSAFE_REFCOUNTING(gfxFontFamily)

    explicit gfxFontFamily(const nsAString& aName) :
        mName(aName),
        mOtherFamilyNamesInitialized(false),
        mHasOtherFamilyNames(false),
        mFaceNamesInitialized(false),
        mHasStyles(false),
        mIsSimpleFamily(false),
        mIsBadUnderlineFamily(false),
        mFamilyCharacterMapInitialized(false),
        mSkipDefaultFeatureSpaceCheck(false),
        mCheckForFallbackFaces(false),
        mCheckedForLegacyFamilyNames(false)
        { }

    const nsString& Name() { return mName; }

    virtual void LocalizedName(nsAString& aLocalizedName);
    virtual bool HasOtherFamilyNames();

    // See https://bugzilla.mozilla.org/show_bug.cgi?id=835204:
    // check the font's 'name' table to see if it has a legacy family name
    // that would have been used by GDI (e.g. to split extra-bold or light
    // faces in a large family into separate "styled families" because of
    // GDI's 4-faces-per-family limitation). If found, the styled family
    // name will be added to the font list's "other family names" table.
    bool CheckForLegacyFamilyNames(gfxPlatformFontList* aFontList);

    nsTArray<RefPtr<gfxFontEntry> >& GetFontList() { return mAvailableFonts; }
    
    void AddFontEntry(RefPtr<gfxFontEntry> aFontEntry) {
        // bug 589682 - set the IgnoreGDEF flag on entries for Italic faces
        // of Times New Roman, because of buggy table in those fonts
        if (aFontEntry->IsItalic() && !aFontEntry->IsUserFont() &&
            Name().EqualsLiteral("Times New Roman"))
        {
            aFontEntry->mIgnoreGDEF = true;
        }
        if (aFontEntry->mFamilyName.IsEmpty()) {
            aFontEntry->mFamilyName = Name();
        } else {
            MOZ_ASSERT(aFontEntry->mFamilyName.Equals(Name()));
        }
        aFontEntry->mSkipDefaultFeatureSpaceCheck = mSkipDefaultFeatureSpaceCheck;
        mAvailableFonts.AppendElement(aFontEntry);

        // If we're adding a face to a family that has been marked as "simple",
        // we need to ensure any null entries are removed, as well as clearing
        // the flag (which may be set again later).
        if (mIsSimpleFamily) {
            for (size_t i = mAvailableFonts.Length() - 1; i-- > 0; ) {
                if (!mAvailableFonts[i]) {
                    mAvailableFonts.RemoveElementAt(i);
                }
            }
            mIsSimpleFamily = false;
        }
    }

    // note that the styles for this family have been added
    bool HasStyles() { return mHasStyles; }
    void SetHasStyles(bool aHasStyles) { mHasStyles = aHasStyles; }

    // choose a specific face to match a style using CSS font matching
    // rules (weight matching occurs here).  may return a face that doesn't
    // precisely match (e.g. normal face when no italic face exists).
    // aNeedsSyntheticBold is set to true when synthetic bolding is
    // needed, false otherwise
    gfxFontEntry *FindFontForStyle(const gfxFontStyle& aFontStyle, 
                                   bool& aNeedsSyntheticBold,
                                   bool aIgnoreSizeTolerance = false);

    virtual void
    FindAllFontsForStyle(const gfxFontStyle& aFontStyle,
                         nsTArray<gfxFontEntry*>& aFontEntryList,
                         bool& aNeedsSyntheticBold,
                         bool aIgnoreSizeTolerance = false);

    // checks for a matching font within the family
    // used as part of the font fallback process
    void FindFontForChar(GlobalFontMatch *aMatchData);

    // checks all fonts for a matching font within the family
    void SearchAllFontsForChar(GlobalFontMatch *aMatchData);

    // read in other family names, if any, and use functor to add each into cache
    virtual void ReadOtherFamilyNames(gfxPlatformFontList *aPlatformFontList);

    // helper method for reading localized family names from the name table
    // of a single face
    static void ReadOtherFamilyNamesForFace(const nsAString& aFamilyName,
                                            const char *aNameData,
                                            uint32_t aDataLength,
                                            nsTArray<nsString>& aOtherFamilyNames,
                                            bool useFullName);

    // set when other family names have been read in
    void SetOtherFamilyNamesInitialized() {
        mOtherFamilyNamesInitialized = true;
    }

    // read in other localized family names, fullnames and Postscript names
    // for all faces and append to lookup tables
    virtual void ReadFaceNames(gfxPlatformFontList *aPlatformFontList,
                               bool aNeedFullnamePostscriptNames,
                               FontInfoData *aFontInfoData = nullptr);

    // find faces belonging to this family (platform implementations override this;
    // should be made pure virtual once all subclasses have been updated)
    virtual void FindStyleVariations(FontInfoData *aFontInfoData = nullptr) { }

    // search for a specific face using the Postscript name
    gfxFontEntry* FindFont(const nsAString& aPostscriptName);

    // read in cmaps for all the faces
    void ReadAllCMAPs(FontInfoData *aFontInfoData = nullptr);

    bool TestCharacterMap(uint32_t aCh) {
        if (!mFamilyCharacterMapInitialized) {
            ReadAllCMAPs();
        }
        return mFamilyCharacterMap.test(aCh);
    }

    void ResetCharacterMap() {
        mFamilyCharacterMap.reset();
        mFamilyCharacterMapInitialized = false;
    }

    // mark this family as being in the "bad" underline offset blacklist
    void SetBadUnderlineFamily() {
        mIsBadUnderlineFamily = true;
        if (mHasStyles) {
            SetBadUnderlineFonts();
        }
    }

    bool IsBadUnderlineFamily() const { return mIsBadUnderlineFamily; }
    bool CheckForFallbackFaces() const { return mCheckForFallbackFaces; }

    // sort available fonts to put preferred (standard) faces towards the end
    void SortAvailableFonts();

    // check whether the family fits into the simple 4-face model,
    // so we can use simplified style-matching;
    // if so set the mIsSimpleFamily flag (defaults to False before we've checked)
    void CheckForSimpleFamily();

    // For memory reporter
    virtual void AddSizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf,
                                        FontListSizes* aSizes) const;
    virtual void AddSizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf,
                                        FontListSizes* aSizes) const;

#ifdef DEBUG
    // Only used for debugging checks - does a linear search
    bool ContainsFace(gfxFontEntry* aFontEntry);
#endif

    void SetSkipSpaceFeatureCheck(bool aSkipCheck) {
        mSkipDefaultFeatureSpaceCheck = aSkipCheck;
    }

    // Check whether this family is appropriate to include in the Preferences
    // font list for the given langGroup and CSS generic, if the platform lets
    // us determine this.
    // Return true if the family should be included in the list, false to omit.
    // Default implementation returns true for everything, so no filtering
    // will occur; individual platforms may override.
    virtual bool FilterForFontList(nsAtom* aLangGroup,
                                   const nsACString& aGeneric) const {
        return true;
    }

protected:
    // Protected destructor, to discourage deletion outside of Release():
    virtual ~gfxFontFamily();

    bool ReadOtherFamilyNamesForFace(gfxPlatformFontList *aPlatformFontList,
                                     hb_blob_t           *aNameTable,
                                     bool                 useFullName = false);

    // set whether this font family is in "bad" underline offset blacklist.
    void SetBadUnderlineFonts() {
        uint32_t i, numFonts = mAvailableFonts.Length();
        for (i = 0; i < numFonts; i++) {
            if (mAvailableFonts[i]) {
                mAvailableFonts[i]->mIsBadUnderlineFont = true;
            }
        }
    }

    nsString mName;
    nsTArray<RefPtr<gfxFontEntry> >  mAvailableFonts;
    gfxSparseBitSet mFamilyCharacterMap;
    bool mOtherFamilyNamesInitialized : 1;
    bool mHasOtherFamilyNames : 1;
    bool mFaceNamesInitialized : 1;
    bool mHasStyles : 1;
    bool mIsSimpleFamily : 1;
    bool mIsBadUnderlineFamily : 1;
    bool mFamilyCharacterMapInitialized : 1;
    bool mSkipDefaultFeatureSpaceCheck : 1;
    bool mCheckForFallbackFaces : 1;  // check other faces for character
    bool mCheckedForLegacyFamilyNames : 1;

    enum {
        // for "simple" families, the faces are stored in mAvailableFonts
        // with fixed positions:
        kRegularFaceIndex    = 0,
        kBoldFaceIndex       = 1,
        kItalicFaceIndex     = 2,
        kBoldItalicFaceIndex = 3,
        // mask values for selecting face with bold and/or italic attributes
        kBoldMask   = 0x01,
        kItalicMask = 0x02
    };
};

#endif