/* -*- Mode: C++; tab-width: 20; 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/. */

#include "gfxFontEntry.h"

#include "mozilla/DebugOnly.h"
#include "mozilla/FontPropertyTypes.h"
#include "mozilla/MathAlgorithms.h"

#include "mozilla/Logging.h"

#include "gfxTextRun.h"
#include "gfxPlatform.h"
#include "nsGkAtoms.h"

#include "gfxTypes.h"
#include "gfxContext.h"
#include "gfxFontConstants.h"
#include "gfxHarfBuzzShaper.h"
#include "gfxUserFontSet.h"
#include "gfxPlatformFontList.h"
#include "nsUnicodeProperties.h"
#include "nsMathUtils.h"
#include "nsBidiUtils.h"
#include "nsStyleConsts.h"
#include "mozilla/AppUnits.h"
#include "mozilla/FloatingPoint.h"
#include "mozilla/Likely.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/Preferences.h"
#include "mozilla/Services.h"
#include "mozilla/StaticPrefs.h"
#include "mozilla/Telemetry.h"
#include "gfxSVGGlyphs.h"
#include "gfx2DGlue.h"

#include "harfbuzz/hb.h"
#include "harfbuzz/hb-ot.h"
#include "graphite2/Font.h"

#include <algorithm>

using namespace mozilla;
using namespace mozilla::gfx;
using namespace mozilla::unicode;
using mozilla::services::GetObserverService;

void gfxCharacterMap::NotifyReleased() {
  gfxPlatformFontList* fontlist = gfxPlatformFontList::PlatformFontList();
  if (mShared) {
    fontlist->RemoveCmap(this);
  }
  delete this;
}

gfxFontEntry::gfxFontEntry()
    : mFixedPitch(false),
      mIsBadUnderlineFont(false),
      mIsUserFontContainer(false),
      mIsDataUserFont(false),
      mIsLocalUserFont(false),
      mStandardFace(false),
      mIgnoreGDEF(false),
      mIgnoreGSUB(false),
      mSVGInitialized(false),
      mHasSpaceFeaturesInitialized(false),
      mHasSpaceFeatures(false),
      mHasSpaceFeaturesKerning(false),
      mHasSpaceFeaturesNonKerning(false),
      mSkipDefaultFeatureSpaceCheck(false),
      mGraphiteSpaceContextualsInitialized(false),
      mHasGraphiteSpaceContextuals(false),
      mSpaceGlyphIsInvisible(false),
      mSpaceGlyphIsInvisibleInitialized(false),
      mHasGraphiteTables(false),
      mCheckedForGraphiteTables(false),
      mHasCmapTable(false),
      mGrFaceInitialized(false),
      mCheckedForColorGlyph(false),
      mCheckedForVariationAxes(false) {
  memset(&mDefaultSubSpaceFeatures, 0, sizeof(mDefaultSubSpaceFeatures));
  memset(&mNonDefaultSubSpaceFeatures, 0, sizeof(mNonDefaultSubSpaceFeatures));
}

gfxFontEntry::gfxFontEntry(const nsACString& aName, bool aIsStandardFace)
    : mName(aName),
      mFixedPitch(false),
      mIsBadUnderlineFont(false),
      mIsUserFontContainer(false),
      mIsDataUserFont(false),
      mIsLocalUserFont(false),
      mStandardFace(aIsStandardFace),
      mIgnoreGDEF(false),
      mIgnoreGSUB(false),
      mSVGInitialized(false),
      mHasSpaceFeaturesInitialized(false),
      mHasSpaceFeatures(false),
      mHasSpaceFeaturesKerning(false),
      mHasSpaceFeaturesNonKerning(false),
      mSkipDefaultFeatureSpaceCheck(false),
      mGraphiteSpaceContextualsInitialized(false),
      mHasGraphiteSpaceContextuals(false),
      mSpaceGlyphIsInvisible(false),
      mSpaceGlyphIsInvisibleInitialized(false),
      mHasGraphiteTables(false),
      mCheckedForGraphiteTables(false),
      mHasCmapTable(false),
      mGrFaceInitialized(false),
      mCheckedForColorGlyph(false),
      mCheckedForVariationAxes(false) {
  memset(&mDefaultSubSpaceFeatures, 0, sizeof(mDefaultSubSpaceFeatures));
  memset(&mNonDefaultSubSpaceFeatures, 0, sizeof(mNonDefaultSubSpaceFeatures));
}

gfxFontEntry::~gfxFontEntry() {
  // Should not be dropped by stylo
  MOZ_ASSERT(NS_IsMainThread());
  hb_blob_destroy(mCOLR);
  hb_blob_destroy(mCPAL);

  // For downloaded fonts, we need to tell the user font cache that this
  // entry is being deleted.
  if (mIsDataUserFont) {
    gfxUserFontSet::UserFontCache::ForgetFont(this);
  }

  if (mFeatureInputs) {
    for (auto iter = mFeatureInputs->Iter(); !iter.Done(); iter.Next()) {
      hb_set_t*& set = iter.Data();
      hb_set_destroy(set);
    }
  }

  // By the time the entry is destroyed, all font instances that were
  // using it should already have been deleted, and so the HB and/or Gr
  // face objects should have been released.
  MOZ_ASSERT(!mHBFace);
  MOZ_ASSERT(!mGrFaceInitialized);
}

bool gfxFontEntry::TestCharacterMap(uint32_t aCh) {
  if (!mCharacterMap && !mShmemCharacterMap) {
    ReadCMAP();
    MOZ_ASSERT(mCharacterMap || mShmemCharacterMap,
               "failed to initialize character map");
  }
  return mShmemCharacterMap ? mShmemCharacterMap->test(aCh)
                            : mCharacterMap->test(aCh);
}

nsresult gfxFontEntry::InitializeUVSMap() {
  // mUVSOffset will not be initialized
  // until cmap is initialized.
  if (!mCharacterMap) {
    ReadCMAP();
    NS_ASSERTION(mCharacterMap, "failed to initialize character map");
  }

  if (!mUVSOffset) {
    return NS_ERROR_FAILURE;
  }

  if (!mUVSData) {
    const uint32_t kCmapTag = TRUETYPE_TAG('c', 'm', 'a', 'p');
    AutoTable cmapTable(this, kCmapTag);
    if (!cmapTable) {
      mUVSOffset = 0;  // don't bother to read the table again
      return NS_ERROR_FAILURE;
    }

    UniquePtr<uint8_t[]> uvsData;
    unsigned int cmapLen;
    const char* cmapData = hb_blob_get_data(cmapTable, &cmapLen);
    nsresult rv = gfxFontUtils::ReadCMAPTableFormat14(
        (const uint8_t*)cmapData + mUVSOffset, cmapLen - mUVSOffset, uvsData);

    if (NS_FAILED(rv)) {
      mUVSOffset = 0;  // don't bother to read the table again
      return rv;
    }

    mUVSData = std::move(uvsData);
  }

  return NS_OK;
}

uint16_t gfxFontEntry::GetUVSGlyph(uint32_t aCh, uint32_t aVS) {
  InitializeUVSMap();

  if (mUVSData) {
    return gfxFontUtils::MapUVSToGlyphFormat14(mUVSData.get(), aCh, aVS);
  }

  return 0;
}

bool gfxFontEntry::SupportsScriptInGSUB(const hb_tag_t* aScriptTags,
                                        uint32_t aNumTags) {
  hb_face_t* face = GetHBFace();
  if (!face) {
    return false;
  }

  unsigned int index;
  hb_tag_t chosenScript;
  bool found = hb_ot_layout_table_select_script(
      face, TRUETYPE_TAG('G', 'S', 'U', 'B'), aNumTags, aScriptTags, &index,
      &chosenScript);
  hb_face_destroy(face);

  return found && chosenScript != TRUETYPE_TAG('D', 'F', 'L', 'T');
}

nsresult gfxFontEntry::ReadCMAP(FontInfoData* aFontInfoData) {
  NS_ASSERTION(false, "using default no-op implementation of ReadCMAP");
  mCharacterMap = new gfxCharacterMap();
  return NS_OK;
}

nsCString gfxFontEntry::RealFaceName() {
  AutoTable nameTable(this, TRUETYPE_TAG('n', 'a', 'm', 'e'));
  if (nameTable) {
    nsAutoCString name;
    nsresult rv = gfxFontUtils::GetFullNameFromTable(nameTable, name);
    if (NS_SUCCEEDED(rv)) {
      return std::move(name);
    }
  }
  return Name();
}

gfxFont* gfxFontEntry::FindOrMakeFont(const gfxFontStyle* aStyle,
                                      gfxCharacterMap* aUnicodeRangeMap) {
  // the font entry name is the psname, not the family name
  gfxFont* font =
      gfxFontCache::GetCache()->Lookup(this, aStyle, aUnicodeRangeMap);

  if (!font) {
    gfxFont* newFont = CreateFontInstance(aStyle);
    if (!newFont) {
      return nullptr;
    }
    if (!newFont->Valid()) {
      delete newFont;
      return nullptr;
    }
    font = newFont;
    font->SetUnicodeRangeMap(aUnicodeRangeMap);
    gfxFontCache::GetCache()->AddNew(font);
  }
  return font;
}

uint16_t gfxFontEntry::UnitsPerEm() {
  if (!mUnitsPerEm) {
    AutoTable headTable(this, TRUETYPE_TAG('h', 'e', 'a', 'd'));
    if (headTable) {
      uint32_t len;
      const HeadTable* head =
          reinterpret_cast<const HeadTable*>(hb_blob_get_data(headTable, &len));
      if (len >= sizeof(HeadTable)) {
        mUnitsPerEm = head->unitsPerEm;
      }
    }

    // if we didn't find a usable 'head' table, or if the value was
    // outside the valid range, record it as invalid
    if (mUnitsPerEm < kMinUPEM || mUnitsPerEm > kMaxUPEM) {
      mUnitsPerEm = kInvalidUPEM;
    }
  }
  return mUnitsPerEm;
}

bool gfxFontEntry::HasSVGGlyph(uint32_t aGlyphId) {
  NS_ASSERTION(mSVGInitialized,
               "SVG data has not yet been loaded. TryGetSVGData() first.");
  return mSVGGlyphs->HasSVGGlyph(aGlyphId);
}

bool gfxFontEntry::GetSVGGlyphExtents(DrawTarget* aDrawTarget,
                                      uint32_t aGlyphId, gfxFloat aSize,
                                      gfxRect* aResult) {
  MOZ_ASSERT(mSVGInitialized,
             "SVG data has not yet been loaded. TryGetSVGData() first.");
  MOZ_ASSERT(mUnitsPerEm >= kMinUPEM && mUnitsPerEm <= kMaxUPEM,
             "font has invalid unitsPerEm");

  gfxMatrix svgToApp(aSize / mUnitsPerEm, 0, 0, aSize / mUnitsPerEm, 0, 0);
  return mSVGGlyphs->GetGlyphExtents(aGlyphId, svgToApp, aResult);
}

void gfxFontEntry::RenderSVGGlyph(gfxContext* aContext, uint32_t aGlyphId,
                                  SVGContextPaint* aContextPaint) {
  NS_ASSERTION(mSVGInitialized,
               "SVG data has not yet been loaded. TryGetSVGData() first.");
  mSVGGlyphs->RenderGlyph(aContext, aGlyphId, aContextPaint);
}

bool gfxFontEntry::TryGetSVGData(gfxFont* aFont) {
  if (!gfxPlatform::GetPlatform()->OpenTypeSVGEnabled()) {
    return false;
  }

  if (!mSVGInitialized) {
    mSVGInitialized = true;

    // If UnitsPerEm is not known/valid, we can't use SVG glyphs
    if (UnitsPerEm() == kInvalidUPEM) {
      return false;
    }

    // We don't use AutoTable here because we'll pass ownership of this
    // blob to the gfxSVGGlyphs, once we've confirmed the table exists
    hb_blob_t* svgTable = GetFontTable(TRUETYPE_TAG('S', 'V', 'G', ' '));
    if (!svgTable) {
      return false;
    }

    // gfxSVGGlyphs will hb_blob_destroy() the table when it is finished
    // with it.
    mSVGGlyphs = MakeUnique<gfxSVGGlyphs>(svgTable, this);
  }

  if (mSVGGlyphs && !mFontsUsingSVGGlyphs.Contains(aFont)) {
    mFontsUsingSVGGlyphs.AppendElement(aFont);
  }

  return !!mSVGGlyphs;
}

void gfxFontEntry::NotifyFontDestroyed(gfxFont* aFont) {
  mFontsUsingSVGGlyphs.RemoveElement(aFont);
}

void gfxFontEntry::NotifyGlyphsChanged() {
  for (uint32_t i = 0, count = mFontsUsingSVGGlyphs.Length(); i < count; ++i) {
    gfxFont* font = mFontsUsingSVGGlyphs[i];
    font->NotifyGlyphsChanged();
  }
}

bool gfxFontEntry::TryGetColorGlyphs() {
  if (mCheckedForColorGlyph) {
    return (mCOLR && mCPAL);
  }

  mCheckedForColorGlyph = true;

  mCOLR = GetFontTable(TRUETYPE_TAG('C', 'O', 'L', 'R'));
  if (!mCOLR) {
    return false;
  }

  mCPAL = GetFontTable(TRUETYPE_TAG('C', 'P', 'A', 'L'));
  if (!mCPAL) {
    hb_blob_destroy(mCOLR);
    mCOLR = nullptr;
    return false;
  }

  // validation COLR and CPAL table
  if (gfxFontUtils::ValidateColorGlyphs(mCOLR, mCPAL)) {
    return true;
  }

  hb_blob_destroy(mCOLR);
  hb_blob_destroy(mCPAL);
  mCOLR = nullptr;
  mCPAL = nullptr;
  return false;
}

/**
 * FontTableBlobData
 *
 * See FontTableHashEntry for the general strategy.
 */

class gfxFontEntry::FontTableBlobData {
 public:
  explicit FontTableBlobData(nsTArray<uint8_t>&& aBuffer)
      : mTableData(std::move(aBuffer)), mHashtable(nullptr), mHashKey(0) {
    MOZ_COUNT_CTOR(FontTableBlobData);
  }

  ~FontTableBlobData() {
    MOZ_COUNT_DTOR(FontTableBlobData);
    if (mHashtable && mHashKey) {
      mHashtable->RemoveEntry(mHashKey);
    }
  }

  // Useful for creating blobs
  const char* GetTable() const {
    return reinterpret_cast<const char*>(mTableData.Elements());
  }
  uint32_t GetTableLength() const { return mTableData.Length(); }

  // Tell this FontTableBlobData to remove the HashEntry when this is
  // destroyed.
  void ManageHashEntry(nsTHashtable<FontTableHashEntry>* aHashtable,
                       uint32_t aHashKey) {
    mHashtable = aHashtable;
    mHashKey = aHashKey;
  }

  // Disconnect from the HashEntry (because the blob has already been
  // removed from the hashtable).
  void ForgetHashEntry() {
    mHashtable = nullptr;
    mHashKey = 0;
  }

  size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
    return mTableData.ShallowSizeOfExcludingThis(aMallocSizeOf);
  }
  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const {
    return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
  }

 private:
  // The font table data block
  nsTArray<uint8_t> mTableData;

  // The blob destroy function needs to know the owning hashtable
  // and the hashtable key, so that it can remove the entry.
  nsTHashtable<FontTableHashEntry>* mHashtable;
  uint32_t mHashKey;

  // not implemented
  FontTableBlobData(const FontTableBlobData&);
};

hb_blob_t* gfxFontEntry::FontTableHashEntry::ShareTableAndGetBlob(
    nsTArray<uint8_t>&& aTable, nsTHashtable<FontTableHashEntry>* aHashtable) {
  Clear();
  // adopts elements of aTable
  mSharedBlobData = new FontTableBlobData(std::move(aTable));

  mBlob = hb_blob_create(
      mSharedBlobData->GetTable(), mSharedBlobData->GetTableLength(),
      HB_MEMORY_MODE_READONLY, mSharedBlobData, DeleteFontTableBlobData);
  if (mBlob == hb_blob_get_empty()) {
    // The FontTableBlobData was destroyed during hb_blob_create().
    // The (empty) blob is still be held in the hashtable with a strong
    // reference.
    return hb_blob_reference(mBlob);
  }

  // Tell the FontTableBlobData to remove this hash entry when destroyed.
  // The hashtable does not keep a strong reference.
  mSharedBlobData->ManageHashEntry(aHashtable, GetKey());
  return mBlob;
}

void gfxFontEntry::FontTableHashEntry::Clear() {
  // If the FontTableBlobData is managing the hash entry, then the blob is
  // not owned by this HashEntry; otherwise there is strong reference to the
  // blob that must be removed.
  if (mSharedBlobData) {
    mSharedBlobData->ForgetHashEntry();
    mSharedBlobData = nullptr;
  } else {
    hb_blob_destroy(mBlob);
  }
  mBlob = nullptr;
}

// a hb_destroy_func for hb_blob_create

/* static */
void gfxFontEntry::FontTableHashEntry::DeleteFontTableBlobData(
    void* aBlobData) {
  delete static_cast<FontTableBlobData*>(aBlobData);
}

hb_blob_t* gfxFontEntry::FontTableHashEntry::GetBlob() const {
  return hb_blob_reference(mBlob);
}

bool gfxFontEntry::GetExistingFontTable(uint32_t aTag, hb_blob_t** aBlob) {
  if (!mFontTableCache) {
    // we do this here rather than on fontEntry construction
    // because not all shapers will access the table cache at all
    mFontTableCache = MakeUnique<nsTHashtable<FontTableHashEntry>>(8);
  }

  FontTableHashEntry* entry = mFontTableCache->GetEntry(aTag);
  if (!entry) {
    return false;
  }

  *aBlob = entry->GetBlob();
  return true;
}

hb_blob_t* gfxFontEntry::ShareFontTableAndGetBlob(uint32_t aTag,
                                                  nsTArray<uint8_t>* aBuffer) {
  if (MOZ_UNLIKELY(!mFontTableCache)) {
    // we do this here rather than on fontEntry construction
    // because not all shapers will access the table cache at all
    mFontTableCache = MakeUnique<nsTHashtable<FontTableHashEntry>>(8);
  }

  FontTableHashEntry* entry = mFontTableCache->PutEntry(aTag);
  if (MOZ_UNLIKELY(!entry)) {  // OOM
    return nullptr;
  }

  if (!aBuffer) {
    // ensure the entry is null
    entry->Clear();
    return nullptr;
  }

  return entry->ShareTableAndGetBlob(std::move(*aBuffer),
                                     mFontTableCache.get());
}

already_AddRefed<gfxCharacterMap> gfxFontEntry::GetCMAPFromFontInfo(
    FontInfoData* aFontInfoData, uint32_t& aUVSOffset) {
  if (!aFontInfoData || !aFontInfoData->mLoadCmaps) {
    return nullptr;
  }

  return aFontInfoData->GetCMAP(mName, aUVSOffset);
}

hb_blob_t* gfxFontEntry::GetFontTable(uint32_t aTag) {
  hb_blob_t* blob;
  if (GetExistingFontTable(aTag, &blob)) {
    return blob;
  }

  nsTArray<uint8_t> buffer;
  bool haveTable = NS_SUCCEEDED(CopyFontTable(aTag, buffer));

  return ShareFontTableAndGetBlob(aTag, haveTable ? &buffer : nullptr);
}

// callback for HarfBuzz to get a font table (in hb_blob_t form)
// from the font entry (passed as aUserData)
/*static*/
hb_blob_t* gfxFontEntry::HBGetTable(hb_face_t* face, uint32_t aTag,
                                    void* aUserData) {
  gfxFontEntry* fontEntry = static_cast<gfxFontEntry*>(aUserData);

  // bug 589682 - ignore the GDEF table in buggy fonts (applies to
  // Italic and BoldItalic faces of Times New Roman)
  if (aTag == TRUETYPE_TAG('G', 'D', 'E', 'F') && fontEntry->IgnoreGDEF()) {
    return nullptr;
  }

  // bug 721719 - ignore the GSUB table in buggy fonts (applies to Roboto,
  // at least on some Android ICS devices; set in gfxFT2FontList.cpp)
  if (aTag == TRUETYPE_TAG('G', 'S', 'U', 'B') && fontEntry->IgnoreGSUB()) {
    return nullptr;
  }

  return fontEntry->GetFontTable(aTag);
}

/*static*/
void gfxFontEntry::HBFaceDeletedCallback(void* aUserData) {
  gfxFontEntry* fe = static_cast<gfxFontEntry*>(aUserData);
  fe->ForgetHBFace();
}

void gfxFontEntry::ForgetHBFace() { mHBFace = nullptr; }

hb_face_t* gfxFontEntry::GetHBFace() {
  if (!mHBFace) {
    mHBFace =
        hb_face_create_for_tables(HBGetTable, this, HBFaceDeletedCallback);
    return mHBFace;
  }
  return hb_face_reference(mHBFace);
}

/*static*/ const void* gfxFontEntry::GrGetTable(const void* aAppFaceHandle,
                                                unsigned int aName,
                                                size_t* aLen) {
  gfxFontEntry* fontEntry =
      static_cast<gfxFontEntry*>(const_cast<void*>(aAppFaceHandle));
  hb_blob_t* blob = fontEntry->GetFontTable(aName);
  if (blob) {
    unsigned int blobLength;
    const void* tableData = hb_blob_get_data(blob, &blobLength);
    fontEntry->mGrTableMap->Put(tableData, blob);
    *aLen = blobLength;
    return tableData;
  }
  *aLen = 0;
  return nullptr;
}

/*static*/
void gfxFontEntry::GrReleaseTable(const void* aAppFaceHandle,
                                  const void* aTableBuffer) {
  gfxFontEntry* fontEntry =
      static_cast<gfxFontEntry*>(const_cast<void*>(aAppFaceHandle));
  void* value;
  if (fontEntry->mGrTableMap->Remove(aTableBuffer, &value)) {
    hb_blob_destroy(static_cast<hb_blob_t*>(value));
  }
}

gr_face* gfxFontEntry::GetGrFace() {
  if (!mGrFaceInitialized) {
    gr_face_ops faceOps = {sizeof(gr_face_ops), GrGetTable, GrReleaseTable};
    mGrTableMap = new nsDataHashtable<nsPtrHashKey<const void>, void*>;
    mGrFace = gr_make_face_with_ops(this, &faceOps, gr_face_default);
    mGrFaceInitialized = true;
  }
  ++mGrFaceRefCnt;
  return mGrFace;
}

void gfxFontEntry::ReleaseGrFace(gr_face* aFace) {
  MOZ_ASSERT(aFace == mGrFace);  // sanity-check
  MOZ_ASSERT(mGrFaceRefCnt > 0);
  if (--mGrFaceRefCnt == 0) {
    gr_face_destroy(mGrFace);
    mGrFace = nullptr;
    mGrFaceInitialized = false;
    delete mGrTableMap;
    mGrTableMap = nullptr;
  }
}

void gfxFontEntry::DisconnectSVG() {
  if (mSVGInitialized && mSVGGlyphs) {
    mSVGGlyphs = nullptr;
    mSVGInitialized = false;
  }
}

bool gfxFontEntry::HasFontTable(uint32_t aTableTag) {
  AutoTable table(this, aTableTag);
  return table && hb_blob_get_length(table) > 0;
}

void gfxFontEntry::CheckForGraphiteTables() {
  mHasGraphiteTables = HasFontTable(TRUETYPE_TAG('S', 'i', 'l', 'f'));
}

bool gfxFontEntry::HasGraphiteSpaceContextuals() {
  if (!mGraphiteSpaceContextualsInitialized) {
    gr_face* face = GetGrFace();
    if (face) {
      const gr_faceinfo* faceInfo = gr_face_info(face, 0);
      mHasGraphiteSpaceContextuals =
          faceInfo->space_contextuals != gr_faceinfo::gr_space_none;
    }
    ReleaseGrFace(face);  // always balance GetGrFace, even if face is null
    mGraphiteSpaceContextualsInitialized = true;
  }
  return mHasGraphiteSpaceContextuals;
}

#define FEATURE_SCRIPT_MASK 0x000000ff  // script index replaces low byte of tag

static_assert(int(Script::NUM_SCRIPT_CODES) <= FEATURE_SCRIPT_MASK,
              "Too many script codes");

// high-order three bytes of tag with script in low-order byte
#define SCRIPT_FEATURE(s, tag)        \
  (((~FEATURE_SCRIPT_MASK) & (tag)) | \
   ((FEATURE_SCRIPT_MASK) & static_cast<uint32_t>(s)))

bool gfxFontEntry::SupportsOpenTypeFeature(Script aScript,
                                           uint32_t aFeatureTag) {
  if (!mSupportedFeatures) {
    mSupportedFeatures = MakeUnique<nsDataHashtable<nsUint32HashKey, bool>>();
  }

  // note: high-order three bytes *must* be unique for each feature
  // listed below (see SCRIPT_FEATURE macro def'n)
  NS_ASSERTION(aFeatureTag == HB_TAG('s', 'm', 'c', 'p') ||
                   aFeatureTag == HB_TAG('c', '2', 's', 'c') ||
                   aFeatureTag == HB_TAG('p', 'c', 'a', 'p') ||
                   aFeatureTag == HB_TAG('c', '2', 'p', 'c') ||
                   aFeatureTag == HB_TAG('s', 'u', 'p', 's') ||
                   aFeatureTag == HB_TAG('s', 'u', 'b', 's') ||
                   aFeatureTag == HB_TAG('v', 'e', 'r', 't'),
               "use of unknown feature tag");

  // note: graphite feature support uses the last script index
  NS_ASSERTION(int(aScript) < FEATURE_SCRIPT_MASK - 1,
               "need to bump the size of the feature shift");

  uint32_t scriptFeature = SCRIPT_FEATURE(aScript, aFeatureTag);
  bool result;
  if (mSupportedFeatures->Get(scriptFeature, &result)) {
    return result;
  }

  result = false;

  hb_face_t* face = GetHBFace();

  if (hb_ot_layout_has_substitution(face)) {
    hb_script_t hbScript =
        gfxHarfBuzzShaper::GetHBScriptUsedForShaping(aScript);

    // Get the OpenType tag(s) that match this script code
    unsigned int scriptCount = 4;
    hb_tag_t scriptTags[4];
    hb_ot_tags_from_script_and_language(hbScript, HB_LANGUAGE_INVALID,
                                        &scriptCount, scriptTags, nullptr,
                                        nullptr);

    // Append DEFAULT to the returned tags, if room
    if (scriptCount < 4) {
      scriptTags[scriptCount++] = HB_OT_TAG_DEFAULT_SCRIPT;
    }

    // Now check for 'smcp' under the first of those scripts that is present
    const hb_tag_t kGSUB = HB_TAG('G', 'S', 'U', 'B');
    for (unsigned int i = 0; i < scriptCount; i++) {
      unsigned int scriptIndex;
      if (hb_ot_layout_table_find_script(face, kGSUB, scriptTags[i],
                                         &scriptIndex)) {
        if (hb_ot_layout_language_find_feature(
                face, kGSUB, scriptIndex, HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX,
                aFeatureTag, nullptr)) {
          result = true;
        }
        break;
      }
    }
  }

  hb_face_destroy(face);

  mSupportedFeatures->Put(scriptFeature, result);

  return result;
}

const hb_set_t* gfxFontEntry::InputsForOpenTypeFeature(Script aScript,
                                                       uint32_t aFeatureTag) {
  if (!mFeatureInputs) {
    mFeatureInputs = MakeUnique<nsDataHashtable<nsUint32HashKey, hb_set_t*>>();
  }

  NS_ASSERTION(aFeatureTag == HB_TAG('s', 'u', 'p', 's') ||
                   aFeatureTag == HB_TAG('s', 'u', 'b', 's') ||
                   aFeatureTag == HB_TAG('v', 'e', 'r', 't'),
               "use of unknown feature tag");

  uint32_t scriptFeature = SCRIPT_FEATURE(aScript, aFeatureTag);
  hb_set_t* inputGlyphs;
  if (mFeatureInputs->Get(scriptFeature, &inputGlyphs)) {
    return inputGlyphs;
  }

  inputGlyphs = hb_set_create();

  hb_face_t* face = GetHBFace();

  if (hb_ot_layout_has_substitution(face)) {
    hb_script_t hbScript =
        gfxHarfBuzzShaper::GetHBScriptUsedForShaping(aScript);

    // Get the OpenType tag(s) that match this script code
    unsigned int scriptCount = 4;
    hb_tag_t scriptTags[5];  // space for null terminator
    hb_ot_tags_from_script_and_language(hbScript, HB_LANGUAGE_INVALID,
                                        &scriptCount, scriptTags, nullptr,
                                        nullptr);

    // Append DEFAULT to the returned tags, if room
    if (scriptCount < 4) {
      scriptTags[scriptCount++] = HB_OT_TAG_DEFAULT_SCRIPT;
    }
    scriptTags[scriptCount++] = 0;

    const hb_tag_t kGSUB = HB_TAG('G', 'S', 'U', 'B');
    hb_tag_t features[2] = {aFeatureTag, HB_TAG_NONE};
    hb_set_t* featurelookups = hb_set_create();
    hb_ot_layout_collect_lookups(face, kGSUB, scriptTags, nullptr, features,
                                 featurelookups);
    hb_codepoint_t index = -1;
    while (hb_set_next(featurelookups, &index)) {
      hb_ot_layout_lookup_collect_glyphs(face, kGSUB, index, nullptr,
                                         inputGlyphs, nullptr, nullptr);
    }
    hb_set_destroy(featurelookups);
  }

  hb_face_destroy(face);

  mFeatureInputs->Put(scriptFeature, inputGlyphs);
  return inputGlyphs;
}

bool gfxFontEntry::SupportsGraphiteFeature(uint32_t aFeatureTag) {
  if (!mSupportedFeatures) {
    mSupportedFeatures = MakeUnique<nsDataHashtable<nsUint32HashKey, bool>>();
  }

  // note: high-order three bytes *must* be unique for each feature
  // listed below (see SCRIPT_FEATURE macro def'n)
  NS_ASSERTION(aFeatureTag == HB_TAG('s', 'm', 'c', 'p') ||
                   aFeatureTag == HB_TAG('c', '2', 's', 'c') ||
                   aFeatureTag == HB_TAG('p', 'c', 'a', 'p') ||
                   aFeatureTag == HB_TAG('c', '2', 'p', 'c') ||
                   aFeatureTag == HB_TAG('s', 'u', 'p', 's') ||
                   aFeatureTag == HB_TAG('s', 'u', 'b', 's'),
               "use of unknown feature tag");

  // graphite feature check uses the last script slot
  uint32_t scriptFeature = SCRIPT_FEATURE(FEATURE_SCRIPT_MASK, aFeatureTag);
  bool result;
  if (mSupportedFeatures->Get(scriptFeature, &result)) {
    return result;
  }

  gr_face* face = GetGrFace();
  result = face ? gr_face_find_fref(face, aFeatureTag) != nullptr : false;
  ReleaseGrFace(face);

  mSupportedFeatures->Put(scriptFeature, result);

  return result;
}

void gfxFontEntry::GetFeatureInfo(nsTArray<gfxFontFeatureInfo>& aFeatureInfo) {
  // TODO: implement alternative code path for graphite fonts

  hb_face_t* face = GetHBFace();

  // Get the list of features for a specific <script,langSys> pair and
  // append them to aFeatureInfo.
  auto collectForLang = [=, &aFeatureInfo](
                            hb_tag_t aTableTag, unsigned int aScript,
                            hb_tag_t aScriptTag, unsigned int aLang,
                            hb_tag_t aLangTag) {
    unsigned int featCount = hb_ot_layout_language_get_feature_tags(
        face, aTableTag, aScript, aLang, 0, nullptr, nullptr);
    AutoTArray<hb_tag_t, 32> featTags;
    featTags.SetLength(featCount);
    hb_ot_layout_language_get_feature_tags(face, aTableTag, aScript, aLang, 0,
                                           &featCount, featTags.Elements());
    MOZ_ASSERT(featCount <= featTags.Length());
    // Just in case HB didn't fill featTags (i.e. in case it returned fewer
    // tags than it promised), we truncate at the length it says it filled:
    featTags.SetLength(featCount);
    for (hb_tag_t t : featTags) {
      aFeatureInfo.AppendElement(gfxFontFeatureInfo{t, aScriptTag, aLangTag});
    }
  };

  // Iterate over the language systems supported by a given script,
  // and call collectForLang for each of them.
  auto collectForScript = [=](hb_tag_t aTableTag, unsigned int aScript,
                              hb_tag_t aScriptTag) {
    collectForLang(aTableTag, aScript, aScriptTag,
                   HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX,
                   HB_TAG('d', 'f', 'l', 't'));
    unsigned int langCount = hb_ot_layout_script_get_language_tags(
        face, aTableTag, aScript, 0, nullptr, nullptr);
    AutoTArray<hb_tag_t, 32> langTags;
    langTags.SetLength(langCount);
    hb_ot_layout_script_get_language_tags(face, aTableTag, aScript, 0,
                                          &langCount, langTags.Elements());
    MOZ_ASSERT(langCount <= langTags.Length());
    langTags.SetLength(langCount);
    for (unsigned int lang = 0; lang < langCount; ++lang) {
      collectForLang(aTableTag, aScript, aScriptTag, lang, langTags[lang]);
    }
  };

  // Iterate over the scripts supported by a table (GSUB or GPOS), and call
  // collectForScript for each of them.
  auto collectForTable = [=](hb_tag_t aTableTag) {
    unsigned int scriptCount = hb_ot_layout_table_get_script_tags(
        face, aTableTag, 0, nullptr, nullptr);
    AutoTArray<hb_tag_t, 32> scriptTags;
    scriptTags.SetLength(scriptCount);
    hb_ot_layout_table_get_script_tags(face, aTableTag, 0, &scriptCount,
                                       scriptTags.Elements());
    MOZ_ASSERT(scriptCount <= scriptTags.Length());
    scriptTags.SetLength(scriptCount);
    for (unsigned int script = 0; script < scriptCount; ++script) {
      collectForScript(aTableTag, script, scriptTags[script]);
    }
  };

  // Collect all OpenType Layout features, both substitution and positioning,
  // supported by the font resource.
  collectForTable(HB_TAG('G', 'S', 'U', 'B'));
  collectForTable(HB_TAG('G', 'P', 'O', 'S'));

  hb_face_destroy(face);
}

bool gfxFontEntry::GetColorLayersInfo(
    uint32_t aGlyphId, const mozilla::gfx::Color& aDefaultColor,
    nsTArray<uint16_t>& aLayerGlyphs,
    nsTArray<mozilla::gfx::Color>& aLayerColors) {
  return gfxFontUtils::GetColorGlyphLayers(
      mCOLR, mCPAL, aGlyphId, aDefaultColor, aLayerGlyphs, aLayerColors);
}

void gfxFontEntry::SetupVariationRanges() {
  if (!gfxPlatform::GetPlatform()->HasVariationFontSupport() ||
      !StaticPrefs::layout_css_font_variations_enabled() || !HasVariations() ||
      IsUserFont()) {
    return;
  }
  AutoTArray<gfxFontVariationAxis, 4> axes;
  GetVariationAxes(axes);
  for (const auto& axis : axes) {
    switch (axis.mTag) {
      case HB_TAG('w', 'g', 'h', 't'):
        // If the axis range looks like it doesn't fit the CSS font-weight
        // scale, we don't hook up the high-level property, and we mark
        // the face (in mRangeFlags) as having non-standard weight. This
        // means we won't map CSS font-weight to the axis. Setting 'wght'
        // with font-variation-settings will still work.
        // Strictly speaking, the min value should be checked against 1.0,
        // not 0.0, but we'll allow font makers that amount of leeway, as
        // in practice a number of fonts seem to use 0..1000.
        if (axis.mMinValue >= 0.0f && axis.mMaxValue <= 1000.0f &&
            // If axis.mMaxValue is less than the default weight we already
            // set up, assume the axis has a non-standard range (like Skia)
            // and don't try to map it.
            Weight().Min() <= FontWeight(axis.mMaxValue)) {
          if (FontWeight(axis.mDefaultValue) != Weight().Min()) {
            mStandardFace = false;
          }
          mWeightRange = WeightRange(FontWeight(std::max(1.0f, axis.mMinValue)),
                                     FontWeight(axis.mMaxValue));
        } else {
          mRangeFlags |= RangeFlags::eNonCSSWeight;
        }
        break;

      case HB_TAG('w', 'd', 't', 'h'):
        if (axis.mMinValue >= 0.0f && axis.mMaxValue <= 1000.0f &&
            Stretch().Min() <= FontStretch(axis.mMaxValue)) {
          if (FontStretch(axis.mDefaultValue) != Stretch().Min()) {
            mStandardFace = false;
          }
          mStretchRange = StretchRange(FontStretch(axis.mMinValue),
                                       FontStretch(axis.mMaxValue));
        } else {
          mRangeFlags |= RangeFlags::eNonCSSStretch;
        }
        break;

      case HB_TAG('s', 'l', 'n', 't'):
        if (axis.mMinValue >= -90.0f && axis.mMaxValue <= 90.0f) {
          if (FontSlantStyle::Oblique(axis.mDefaultValue) !=
              SlantStyle().Min()) {
            mStandardFace = false;
          }
          mStyleRange =
              SlantStyleRange(FontSlantStyle::Oblique(axis.mMinValue),
                              FontSlantStyle::Oblique(axis.mMaxValue));
        }
        break;

      case HB_TAG('i', 't', 'a', 'l'):
        if (axis.mMinValue <= 0.0f && axis.mMaxValue >= 1.0f) {
          if (axis.mDefaultValue != 0.0f) {
            mStandardFace = false;
          }
          mStyleRange = SlantStyleRange(FontSlantStyle::Normal(),
                                        FontSlantStyle::Italic());
        }
        break;

      default:
        continue;
    }
  }
}

void gfxFontEntry::CheckForVariationAxes() {
  if (HasVariations()) {
    AutoTArray<gfxFontVariationAxis, 4> axes;
    GetVariationAxes(axes);
    for (const auto& axis : axes) {
      if (axis.mTag == HB_TAG('w', 'g', 'h', 't') && axis.mMaxValue >= 600.0f) {
        mRangeFlags |= RangeFlags::eBoldVariableWeight;
      } else if (axis.mTag == HB_TAG('i', 't', 'a', 'l') &&
                 axis.mMaxValue >= 1.0f) {
        mRangeFlags |= RangeFlags::eItalicVariation;
      }
    }
  }
  mCheckedForVariationAxes = true;
}

bool gfxFontEntry::HasBoldVariableWeight() {
  MOZ_ASSERT(!mIsUserFontContainer,
             "should not be called for user-font containers!");

  if (!gfxPlatform::GetPlatform()->HasVariationFontSupport()) {
    return false;
  }

  if (!mCheckedForVariationAxes) {
    CheckForVariationAxes();
  }

  return bool(mRangeFlags & RangeFlags::eBoldVariableWeight);
}

bool gfxFontEntry::HasItalicVariation() {
  MOZ_ASSERT(!mIsUserFontContainer,
             "should not be called for user-font containers!");

  if (!gfxPlatform::GetPlatform()->HasVariationFontSupport()) {
    return false;
  }

  if (!mCheckedForVariationAxes) {
    CheckForVariationAxes();
  }

  return bool(mRangeFlags & RangeFlags::eItalicVariation);
}

void gfxFontEntry::GetVariationsForStyle(nsTArray<gfxFontVariation>& aResult,
                                         const gfxFontStyle& aStyle) {
  if (!gfxPlatform::GetPlatform()->HasVariationFontSupport() ||
      !StaticPrefs::layout_css_font_variations_enabled()) {
    return;
  }

  if (!HasVariations()) {
    return;
  }

  // Resolve high-level CSS properties from the requested style
  // (font-{style,weight,stretch}) to the appropriate variations.
  // The value used is clamped to the range available in the font face,
  // unless the face is a user font where no explicit descriptor was
  // given, indicated by the corresponding 'auto' range-flag.

  // We don't do these mappings if the font entry has weight and/or stretch
  // ranges that do not appear to use the CSS property scale. Some older
  // fonts created for QuickDrawGX/AAT may use "normalized" values where the
  // standard variation is 1.0 rather than 400.0 (weight) or 100.0 (stretch).

  if (!(mRangeFlags & RangeFlags::eNonCSSWeight)) {
    float weight = (IsUserFont() && (mRangeFlags & RangeFlags::eAutoWeight))
                       ? aStyle.weight.ToFloat()
                       : Weight().Clamp(aStyle.weight).ToFloat();
    aResult.AppendElement(gfxFontVariation{HB_TAG('w', 'g', 'h', 't'), weight});
  }

  if (!(mRangeFlags & RangeFlags::eNonCSSStretch)) {
    float stretch = (IsUserFont() && (mRangeFlags & RangeFlags::eAutoStretch))
                        ? aStyle.stretch.Percentage()
                        : Stretch().Clamp(aStyle.stretch).Percentage();
    aResult.AppendElement(
        gfxFontVariation{HB_TAG('w', 'd', 't', 'h'), stretch});
  }

  if (aStyle.style.IsItalic() && SupportsItalic()) {
    // The 'ital' axis is normally a binary toggle; intermediate values
    // can only be set using font-variation-settings.
    aResult.AppendElement(gfxFontVariation{HB_TAG('i', 't', 'a', 'l'), 1.0f});
  } else if (SlantStyle().Min().IsOblique()) {
    // Figure out what slant angle we should try to match from the
    // requested style.
    float angle = aStyle.style.IsNormal()
                      ? 0.0f
                      : aStyle.style.IsItalic()
                            ? FontSlantStyle::Oblique().ObliqueAngle()
                            : aStyle.style.ObliqueAngle();
    // Clamp to the available range, unless the face is a user font
    // with no explicit descriptor.
    if (!(IsUserFont() && (mRangeFlags & RangeFlags::eAutoSlantStyle))) {
      angle = SlantStyle().Clamp(FontSlantStyle::Oblique(angle)).ObliqueAngle();
    }
    aResult.AppendElement(gfxFontVariation{HB_TAG('s', 'l', 'n', 't'), angle});
  }

  auto replaceOrAppend = [&aResult](const gfxFontVariation& aSetting) {
    struct TagEquals {
      bool Equals(const gfxFontVariation& aIter, uint32_t aTag) const {
        return aIter.mTag == aTag;
      }
    };
    auto index = aResult.IndexOf(aSetting.mTag, 0, TagEquals());
    if (index == aResult.NoIndex) {
      aResult.AppendElement(aSetting);
    } else {
      aResult[index].mValue = aSetting.mValue;
    }
  };

  // The low-level font-variation-settings descriptor from @font-face,
  // if present, takes precedence over automatic variation settings
  // from high-level properties.
  for (const auto& v : mVariationSettings) {
    replaceOrAppend(v);
  }

  // And the low-level font-variation-settings property takes precedence
  // over the descriptor.
  for (const auto& v : aStyle.variationSettings) {
    replaceOrAppend(v);
  }
}

size_t gfxFontEntry::FontTableHashEntry::SizeOfExcludingThis(
    mozilla::MallocSizeOf aMallocSizeOf) const {
  size_t n = 0;
  if (mBlob) {
    n += aMallocSizeOf(mBlob);
  }
  if (mSharedBlobData) {
    n += mSharedBlobData->SizeOfIncludingThis(aMallocSizeOf);
  }
  return n;
}

void gfxFontEntry::AddSizeOfExcludingThis(MallocSizeOf aMallocSizeOf,
                                          FontListSizes* aSizes) const {
  aSizes->mFontListSize += mName.SizeOfExcludingThisIfUnshared(aMallocSizeOf);

  // cmaps are shared so only non-shared cmaps are included here
  if (mCharacterMap && mCharacterMap->mBuildOnTheFly) {
    aSizes->mCharMapsSize += mCharacterMap->SizeOfIncludingThis(aMallocSizeOf);
  }
  if (mFontTableCache) {
    aSizes->mFontTableCacheSize +=
        mFontTableCache->SizeOfIncludingThis(aMallocSizeOf);
  }

  // If the font has UVS data, we count that as part of the character map.
  if (mUVSData) {
    aSizes->mCharMapsSize += aMallocSizeOf(mUVSData.get());
  }

  // The following, if present, are essentially cached forms of font table
  // data, so we'll accumulate them together with the basic table cache.
  if (mUserFontData) {
    aSizes->mFontTableCacheSize +=
        mUserFontData->SizeOfIncludingThis(aMallocSizeOf);
  }
  if (mSVGGlyphs) {
    aSizes->mFontTableCacheSize +=
        mSVGGlyphs->SizeOfIncludingThis(aMallocSizeOf);
  }
  if (mSupportedFeatures) {
    aSizes->mFontTableCacheSize +=
        mSupportedFeatures->ShallowSizeOfIncludingThis(aMallocSizeOf);
  }
  if (mFeatureInputs) {
    aSizes->mFontTableCacheSize +=
        mFeatureInputs->ShallowSizeOfIncludingThis(aMallocSizeOf);
    for (auto iter = mFeatureInputs->ConstIter(); !iter.Done(); iter.Next()) {
      // There's no API to get the real size of an hb_set, so we'll use
      // an approximation based on knowledge of the implementation.
      aSizes->mFontTableCacheSize += 8192;  // vector of 64K bits
    }
  }
  // We don't include the size of mCOLR/mCPAL here, because (depending on the
  // font backend implementation) they will either wrap blocks of data owned
  // by the system (and potentially shared), or tables that are in our font
  // table cache and therefore already counted.
}

void gfxFontEntry::AddSizeOfIncludingThis(MallocSizeOf aMallocSizeOf,
                                          FontListSizes* aSizes) const {
  aSizes->mFontListSize += aMallocSizeOf(this);
  AddSizeOfExcludingThis(aMallocSizeOf, aSizes);
}

// This is used to report the size of an individual downloaded font in the
// user font cache. (Fonts that are part of the platform font list accumulate
// their sizes to the font list's reporter using the AddSizeOf... methods
// above.)
size_t gfxFontEntry::ComputedSizeOfExcludingThis(
    MallocSizeOf aMallocSizeOf) const {
  FontListSizes s = {0};
  AddSizeOfExcludingThis(aMallocSizeOf, &s);

  // When reporting memory used for the main platform font list,
  // where we're typically summing the totals for a few hundred font faces,
  // we report the fields of FontListSizes separately.
  // But for downloaded user fonts, the actual resource data (added below)
  // will dominate, and the minor overhead of these pieces isn't worth
  // splitting out for an individual font.
  size_t result = s.mFontListSize + s.mFontTableCacheSize + s.mCharMapsSize;

  if (mIsDataUserFont) {
    MOZ_ASSERT(mComputedSizeOfUserFont > 0, "user font with no data?");
    result += mComputedSizeOfUserFont;
  }

  return result;
}

//////////////////////////////////////////////////////////////////////////////
//
// class gfxFontFamily
//
//////////////////////////////////////////////////////////////////////////////

// we consider faces with mStandardFace == true to be "less than" those with
// false, because during style matching, earlier entries are tried first
class FontEntryStandardFaceComparator {
 public:
  bool Equals(const RefPtr<gfxFontEntry>& a,
              const RefPtr<gfxFontEntry>& b) const {
    return a->mStandardFace == b->mStandardFace;
  }
  bool LessThan(const RefPtr<gfxFontEntry>& a,
                const RefPtr<gfxFontEntry>& b) const {
    return (a->mStandardFace == true && b->mStandardFace == false);
  }
};

void gfxFontFamily::SortAvailableFonts() {
  mAvailableFonts.Sort(FontEntryStandardFaceComparator());
}

bool gfxFontFamily::HasOtherFamilyNames() {
  // need to read in other family names to determine this
  if (!mOtherFamilyNamesInitialized) {
    ReadOtherFamilyNames(
        gfxPlatformFontList::PlatformFontList());  // sets mHasOtherFamilyNames
  }
  return mHasOtherFamilyNames;
}

gfxFontEntry* gfxFontFamily::FindFontForStyle(const gfxFontStyle& aFontStyle,
                                              bool aIgnoreSizeTolerance) {
  AutoTArray<gfxFontEntry*, 4> matched;
  FindAllFontsForStyle(aFontStyle, matched, aIgnoreSizeTolerance);
  if (!matched.IsEmpty()) {
    return matched[0];
  }
  return nullptr;
}

static inline double WeightStyleStretchDistance(
    gfxFontEntry* aFontEntry, const gfxFontStyle& aTargetStyle) {
  double stretchDist =
      StretchDistance(aFontEntry->Stretch(), aTargetStyle.stretch);
  double styleDist =
      StyleDistance(aFontEntry->SlantStyle(), aTargetStyle.style);
  double weightDist = WeightDistance(aFontEntry->Weight(), aTargetStyle.weight);

  // Sanity-check that the distances are within the expected range
  // (update if implementation of the distance functions is changed).
  MOZ_ASSERT(stretchDist >= 0.0 && stretchDist <= 2000.0);
  MOZ_ASSERT(styleDist >= 0.0 && styleDist <= 500.0);
  MOZ_ASSERT(weightDist >= 0.0 && weightDist <= 1600.0);

  // weight/style/stretch priority: stretch >> style >> weight
  // so we multiply the stretch and style values to make them dominate
  // the result
  return stretchDist * 1.0e8 + styleDist * 1.0e4 + weightDist;
}

void gfxFontFamily::FindAllFontsForStyle(
    const gfxFontStyle& aFontStyle, nsTArray<gfxFontEntry*>& aFontEntryList,
    bool aIgnoreSizeTolerance) {
  if (!mHasStyles) {
    FindStyleVariations();  // collect faces for the family, if not already done
  }

  NS_ASSERTION(mAvailableFonts.Length() > 0, "font family with no faces!");
  NS_ASSERTION(aFontEntryList.IsEmpty(), "non-empty fontlist passed in");

  gfxFontEntry* fe = nullptr;

  // If the family has only one face, we simply return it; no further
  // checking needed
  uint32_t count = mAvailableFonts.Length();
  if (count == 1) {
    fe = mAvailableFonts[0];
    aFontEntryList.AppendElement(fe);
    return;
  }

  // Most families are "simple", having just Regular/Bold/Italic/BoldItalic,
  // or some subset of these. In this case, we have exactly 4 entries in
  // mAvailableFonts, stored in the above order; note that some of the entries
  // may be nullptr. We can then pick the required entry based on whether the
  // request is for bold or non-bold, italic or non-italic, without running the
  // more complex matching algorithm used for larger families with many weights
  // and/or widths.

  if (mIsSimpleFamily) {
    // Family has no more than the "standard" 4 faces, at fixed indexes;
    // calculate which one we want.
    // Note that we cannot simply return it as not all 4 faces are necessarily
    // present.
    bool wantBold = aFontStyle.weight >= FontWeight(600);
    bool wantItalic = !aFontStyle.style.IsNormal();
    uint8_t faceIndex =
        (wantItalic ? kItalicMask : 0) | (wantBold ? kBoldMask : 0);

    // if the desired style is available, return it directly
    fe = mAvailableFonts[faceIndex];
    if (fe) {
      aFontEntryList.AppendElement(fe);
      return;
    }

    // order to check fallback faces in a simple family, depending on requested
    // style
    static const uint8_t simpleFallbacks[4][3] = {
        {kBoldFaceIndex, kItalicFaceIndex,
         kBoldItalicFaceIndex},  // fallbacks for Regular
        {kRegularFaceIndex, kBoldItalicFaceIndex, kItalicFaceIndex},  // Bold
        {kBoldItalicFaceIndex, kRegularFaceIndex, kBoldFaceIndex},    // Italic
        {kItalicFaceIndex, kBoldFaceIndex, kRegularFaceIndex}  // BoldItalic
    };
    const uint8_t* order = simpleFallbacks[faceIndex];

    for (uint8_t trial = 0; trial < 3; ++trial) {
      // check remaining faces in order of preference to find the first that
      // actually exists
      fe = mAvailableFonts[order[trial]];
      if (fe) {
        aFontEntryList.AppendElement(fe);
        return;
      }
    }

    // this can't happen unless we have totally broken the font-list manager!
    MOZ_ASSERT_UNREACHABLE("no face found in simple font family!");
  }

  // Pick the font(s) that are closest to the desired weight, style, and
  // stretch. Iterate over all fonts, measuring the weight/style distance.
  // Because of unicode-range values, there may be more than one font for a
  // given but the 99% use case is only a single font entry per
  // weight/style/stretch distance value. To optimize this, only add entries
  // to the matched font array when another entry already has the same
  // weight/style/stretch distance and add the last matched font entry. For
  // normal platform fonts with a single font entry for each
  // weight/style/stretch combination, only the last matched font entry will
  // be added.

  double minDistance = INFINITY;
  gfxFontEntry* matched = nullptr;
  // iterate in forward order so that faces like 'Bold' are matched before
  // matching style distance faces such as 'Bold Outline' (see bug 1185812)
  for (uint32_t i = 0; i < count; i++) {
    fe = mAvailableFonts[i];
    // weight/style/stretch priority: stretch >> style >> weight
    double distance = WeightStyleStretchDistance(fe, aFontStyle);
    if (distance < minDistance) {
      matched = fe;
      if (!aFontEntryList.IsEmpty()) {
        aFontEntryList.Clear();
      }
      minDistance = distance;
    } else if (distance == minDistance) {
      if (matched) {
        aFontEntryList.AppendElement(matched);
      }
      matched = fe;
    }
  }

  NS_ASSERTION(matched, "didn't match a font within a family");

  if (matched) {
    aFontEntryList.AppendElement(matched);
  }
}

void gfxFontFamily::CheckForSimpleFamily() {
  // already checked this family
  if (mIsSimpleFamily) {
    return;
  }

  uint32_t count = mAvailableFonts.Length();
  if (count > 4 || count == 0) {
    return;  // can't be "simple" if there are >4 faces;
             // if none then the family is unusable anyway
  }

  if (count == 1) {
    mIsSimpleFamily = true;
    return;
  }

  StretchRange firstStretch = mAvailableFonts[0]->Stretch();
  if (!firstStretch.IsSingle()) {
    return;  // family with variation fonts is not considered "simple"
  }

  gfxFontEntry* faces[4] = {0};
  for (uint8_t i = 0; i < count; ++i) {
    gfxFontEntry* fe = mAvailableFonts[i];
    if (fe->Stretch() != firstStretch || fe->IsOblique()) {
      // simple families don't have varying font-stretch or oblique
      return;
    }
    if (!fe->Weight().IsSingle() || !fe->SlantStyle().IsSingle()) {
      return;  // family with variation fonts is not considered "simple"
    }
    uint8_t faceIndex = (fe->IsItalic() ? kItalicMask : 0) |
                        (fe->SupportsBold() ? kBoldMask : 0);
    if (faces[faceIndex]) {
      return;  // two faces resolve to the same slot; family isn't "simple"
    }
    faces[faceIndex] = fe;
  }

  // we have successfully slotted the available faces into the standard
  // 4-face framework
  mAvailableFonts.SetLength(4);
  for (uint8_t i = 0; i < 4; ++i) {
    if (mAvailableFonts[i].get() != faces[i]) {
      mAvailableFonts[i].swap(faces[i]);
    }
  }

  mIsSimpleFamily = true;
}

#ifdef DEBUG
bool gfxFontFamily::ContainsFace(gfxFontEntry* aFontEntry) {
  uint32_t i, numFonts = mAvailableFonts.Length();
  for (i = 0; i < numFonts; i++) {
    if (mAvailableFonts[i] == aFontEntry) {
      return true;
    }
    // userfonts contain the actual real font entry
    if (mAvailableFonts[i] && mAvailableFonts[i]->mIsUserFontContainer) {
      gfxUserFontEntry* ufe =
          static_cast<gfxUserFontEntry*>(mAvailableFonts[i].get());
      if (ufe->GetPlatformFontEntry() == aFontEntry) {
        return true;
      }
    }
  }
  return false;
}
#endif

void gfxFontFamily::LocalizedName(nsACString& aLocalizedName) {
  // just return the primary name; subclasses should override
  aLocalizedName = mName;
}

void gfxFontFamily::FindFontForChar(GlobalFontMatch* aMatchData) {
  if (mFamilyCharacterMapInitialized && !TestCharacterMap(aMatchData->mCh)) {
    // none of the faces in the family support the required char,
    // so bail out immediately
    return;
  }

#ifdef MOZ_GECKO_PROFILER
  nsCString charAndName;
  if (profiler_is_active()) {
    charAndName = nsPrintfCString("\\u%x %s", aMatchData->mCh, mName.get());
  }

  AUTO_PROFILER_LABEL_DYNAMIC_NSCSTRING("gfxFontFamily::FindFontForChar",
                                        LAYOUT, charAndName);
#endif

  AutoTArray<gfxFontEntry*, 4> entries;
  FindAllFontsForStyle(aMatchData->mStyle, entries,
                       /*aIgnoreSizeTolerance*/ true);
  if (entries.IsEmpty()) {
    return;
  }

  gfxFontEntry* fe = nullptr;
  float distance = INFINITY;

  for (auto e : entries) {
    if (e->SkipDuringSystemFallback()) {
      continue;
    }

    aMatchData->mCmapsTested++;
    if (e->HasCharacter(aMatchData->mCh)) {
      aMatchData->mCount++;

      LogModule* log = gfxPlatform::GetLog(eGfxLog_textrun);

      if (MOZ_UNLIKELY(MOZ_LOG_TEST(log, LogLevel::Debug))) {
        Script script = GetScriptCode(aMatchData->mCh);
        MOZ_LOG(log, LogLevel::Debug,
                ("(textrun-systemfallback-fonts) char: u+%6.6x "
                 "script: %d match: [%s]\n",
                 aMatchData->mCh, int(script), e->Name().get()));
      }

      fe = e;
      distance = WeightStyleStretchDistance(fe, aMatchData->mStyle);
      break;
    }
  }

  if (!fe && !aMatchData->mStyle.IsNormalStyle()) {
    // If style/weight/stretch was not Normal, see if we can
    // fall back to a next-best face (e.g. Arial Black -> Bold,
    // or Arial Narrow -> Regular).
    GlobalFontMatch data(aMatchData->mCh, aMatchData->mStyle);
    SearchAllFontsForChar(&data);
    if (!data.mBestMatch) {
      return;
    }
    fe = data.mBestMatch;
    distance = data.mMatchDistance;
  }

  if (!fe) {
    return;
  }

  if (distance < aMatchData->mMatchDistance ||
      (distance == aMatchData->mMatchDistance &&
       Compare(fe->Name(), aMatchData->mBestMatch->Name()) > 0)) {
    aMatchData->mBestMatch = fe;
    aMatchData->mMatchedFamily = this;
    aMatchData->mMatchDistance = distance;
  }
}

void gfxFontFamily::SearchAllFontsForChar(GlobalFontMatch* aMatchData) {
  uint32_t i, numFonts = mAvailableFonts.Length();
  for (i = 0; i < numFonts; i++) {
    gfxFontEntry* fe = mAvailableFonts[i];
    if (fe && fe->HasCharacter(aMatchData->mCh)) {
      float distance = WeightStyleStretchDistance(fe, aMatchData->mStyle);
      if (distance < aMatchData->mMatchDistance ||
          (distance == aMatchData->mMatchDistance &&
           Compare(fe->Name(), aMatchData->mBestMatch->Name()) > 0)) {
        aMatchData->mBestMatch = fe;
        aMatchData->mMatchedFamily = this;
        aMatchData->mMatchDistance = distance;
      }
    }
  }
}

/*virtual*/
gfxFontFamily::~gfxFontFamily() {
  // Should not be dropped by stylo
  MOZ_ASSERT(NS_IsMainThread());
}

// returns true if other names were found, false otherwise
bool gfxFontFamily::ReadOtherFamilyNamesForFace(
    gfxPlatformFontList* aPlatformFontList, hb_blob_t* aNameTable,
    bool useFullName) {
  uint32_t dataLength;
  const char* nameData = hb_blob_get_data(aNameTable, &dataLength);
  AutoTArray<nsCString, 4> otherFamilyNames;

  gfxFontUtils::ReadOtherFamilyNamesForFace(mName, nameData, dataLength,
                                            otherFamilyNames, useFullName);

  uint32_t n = otherFamilyNames.Length();
  for (uint32_t i = 0; i < n; i++) {
    aPlatformFontList->AddOtherFamilyName(this, otherFamilyNames[i]);
  }

  return n != 0;
}

void gfxFontFamily::ReadOtherFamilyNames(
    gfxPlatformFontList* aPlatformFontList) {
  if (mOtherFamilyNamesInitialized) return;
  mOtherFamilyNamesInitialized = true;

  FindStyleVariations();

  // read in other family names for the first face in the list
  uint32_t i, numFonts = mAvailableFonts.Length();
  const uint32_t kNAME = TRUETYPE_TAG('n', 'a', 'm', 'e');

  for (i = 0; i < numFonts; ++i) {
    gfxFontEntry* fe = mAvailableFonts[i];
    if (!fe) {
      continue;
    }
    gfxFontEntry::AutoTable nameTable(fe, kNAME);
    if (!nameTable) {
      continue;
    }
    mHasOtherFamilyNames =
        ReadOtherFamilyNamesForFace(aPlatformFontList, nameTable);
    break;
  }

  // read in other names for the first face in the list with the assumption
  // that if extra names don't exist in that face then they don't exist in
  // other faces for the same font
  if (!mHasOtherFamilyNames) return;

  // read in names for all faces, needed to catch cases where fonts have
  // family names for individual weights (e.g. Hiragino Kaku Gothic Pro W6)
  for (; i < numFonts; i++) {
    gfxFontEntry* fe = mAvailableFonts[i];
    if (!fe) {
      continue;
    }
    gfxFontEntry::AutoTable nameTable(fe, kNAME);
    if (!nameTable) {
      continue;
    }
    ReadOtherFamilyNamesForFace(aPlatformFontList, nameTable);
  }
}

static bool LookForLegacyFamilyName(const nsACString& aCanonicalName,
                                    const char* aNameData, uint32_t aDataLength,
                                    nsACString& aLegacyName /* outparam */) {
  const gfxFontUtils::NameHeader* nameHeader =
      reinterpret_cast<const gfxFontUtils::NameHeader*>(aNameData);

  uint32_t nameCount = nameHeader->count;
  if (nameCount * sizeof(gfxFontUtils::NameRecord) > aDataLength) {
    NS_WARNING("invalid font (name records)");
    return false;
  }

  const gfxFontUtils::NameRecord* nameRecord =
      reinterpret_cast<const gfxFontUtils::NameRecord*>(
          aNameData + sizeof(gfxFontUtils::NameHeader));
  uint32_t stringsBase = uint32_t(nameHeader->stringOffset);

  for (uint32_t i = 0; i < nameCount; i++, nameRecord++) {
    uint32_t nameLen = nameRecord->length;
    uint32_t nameOff = nameRecord->offset;

    if (stringsBase + nameOff + nameLen > aDataLength) {
      NS_WARNING("invalid font (name table strings)");
      return false;
    }

    if (uint16_t(nameRecord->nameID) == gfxFontUtils::NAME_ID_FAMILY) {
      bool ok = gfxFontUtils::DecodeFontName(
          aNameData + stringsBase + nameOff, nameLen,
          uint32_t(nameRecord->platformID), uint32_t(nameRecord->encodingID),
          uint32_t(nameRecord->languageID), aLegacyName);
      // it's only a legacy name if it differs from the canonical name
      if (ok && aLegacyName != aCanonicalName) {
        return true;
      }
    }
  }
  return false;
}

bool gfxFontFamily::CheckForLegacyFamilyNames(gfxPlatformFontList* aFontList) {
  if (mCheckedForLegacyFamilyNames) {
    // we already did this, so there's nothing more to add
    return false;
  }
  mCheckedForLegacyFamilyNames = true;
  bool added = false;
  const uint32_t kNAME = TRUETYPE_TAG('n', 'a', 'm', 'e');
  // Make a local copy of the array of font faces, in case of changes
  // during the iteration.
  AutoTArray<RefPtr<gfxFontEntry>, 8> faces(mAvailableFonts);
  for (auto& fe : faces) {
    if (!fe) {
      continue;
    }
    gfxFontEntry::AutoTable nameTable(fe, kNAME);
    if (!nameTable) {
      continue;
    }
    nsAutoCString legacyName;
    uint32_t dataLength;
    const char* nameData = hb_blob_get_data(nameTable, &dataLength);
    if (LookForLegacyFamilyName(Name(), nameData, dataLength, legacyName)) {
      if (aFontList->AddWithLegacyFamilyName(legacyName, fe)) {
        added = true;
      }
    }
  }
  return added;
}

void gfxFontFamily::ReadFaceNames(gfxPlatformFontList* aPlatformFontList,
                                  bool aNeedFullnamePostscriptNames,
                                  FontInfoData* aFontInfoData) {
  // if all needed names have already been read, skip
  if (mOtherFamilyNamesInitialized &&
      (mFaceNamesInitialized || !aNeedFullnamePostscriptNames)) {
    return;
  }

  bool asyncFontLoaderDisabled = false;

  if (!mOtherFamilyNamesInitialized && aFontInfoData &&
      aFontInfoData->mLoadOtherNames && !asyncFontLoaderDisabled) {
    AutoTArray<nsCString, 4> otherFamilyNames;
    bool foundOtherNames =
        aFontInfoData->GetOtherFamilyNames(mName, otherFamilyNames);
    if (foundOtherNames) {
      uint32_t i, n = otherFamilyNames.Length();
      for (i = 0; i < n; i++) {
        aPlatformFontList->AddOtherFamilyName(this, otherFamilyNames[i]);
      }
    }
    mOtherFamilyNamesInitialized = true;
  }

  // if all needed data has been initialized, return
  if (mOtherFamilyNamesInitialized &&
      (mFaceNamesInitialized || !aNeedFullnamePostscriptNames)) {
    return;
  }

  FindStyleVariations(aFontInfoData);

  // check again, as style enumeration code may have loaded names
  if (mOtherFamilyNamesInitialized &&
      (mFaceNamesInitialized || !aNeedFullnamePostscriptNames)) {
    return;
  }

  uint32_t i, numFonts = mAvailableFonts.Length();
  const uint32_t kNAME = TRUETYPE_TAG('n', 'a', 'm', 'e');

  bool firstTime = true, readAllFaces = false;
  for (i = 0; i < numFonts; ++i) {
    gfxFontEntry* fe = mAvailableFonts[i];
    if (!fe) {
      continue;
    }

    nsAutoCString fullname, psname;
    bool foundFaceNames = false;
    if (!mFaceNamesInitialized && aNeedFullnamePostscriptNames &&
        aFontInfoData && aFontInfoData->mLoadFaceNames) {
      aFontInfoData->GetFaceNames(fe->Name(), fullname, psname);
      if (!fullname.IsEmpty()) {
        aPlatformFontList->AddFullname(fe, fullname);
      }
      if (!psname.IsEmpty()) {
        aPlatformFontList->AddPostscriptName(fe, psname);
      }
      foundFaceNames = true;

      // found everything needed? skip to next font
      if (mOtherFamilyNamesInitialized) {
        continue;
      }
    }

    // load directly from the name table
    gfxFontEntry::AutoTable nameTable(fe, kNAME);
    if (!nameTable) {
      continue;
    }

    if (aNeedFullnamePostscriptNames && !foundFaceNames) {
      if (gfxFontUtils::ReadCanonicalName(nameTable, gfxFontUtils::NAME_ID_FULL,
                                          fullname) == NS_OK) {
        aPlatformFontList->AddFullname(fe, fullname);
      }

      if (gfxFontUtils::ReadCanonicalName(
              nameTable, gfxFontUtils::NAME_ID_POSTSCRIPT, psname) == NS_OK) {
        aPlatformFontList->AddPostscriptName(fe, psname);
      }
    }

    if (!mOtherFamilyNamesInitialized && (firstTime || readAllFaces)) {
      bool foundOtherName =
          ReadOtherFamilyNamesForFace(aPlatformFontList, nameTable);

      // if the first face has a different name, scan all faces, otherwise
      // assume the family doesn't have other names
      if (firstTime && foundOtherName) {
        mHasOtherFamilyNames = true;
        readAllFaces = true;
      }
      firstTime = false;
    }

    // if not reading in any more names, skip other faces
    if (!readAllFaces && !aNeedFullnamePostscriptNames) {
      break;
    }
  }

  mFaceNamesInitialized = true;
  mOtherFamilyNamesInitialized = true;
}

gfxFontEntry* gfxFontFamily::FindFont(const nsACString& aPostscriptName) {
  // find the font using a simple linear search
  uint32_t numFonts = mAvailableFonts.Length();
  for (uint32_t i = 0; i < numFonts; i++) {
    gfxFontEntry* fe = mAvailableFonts[i].get();
    if (fe && fe->Name() == aPostscriptName) return fe;
  }
  return nullptr;
}

void gfxFontFamily::ReadAllCMAPs(FontInfoData* aFontInfoData) {
  FindStyleVariations(aFontInfoData);

  uint32_t i, numFonts = mAvailableFonts.Length();
  for (i = 0; i < numFonts; i++) {
    gfxFontEntry* fe = mAvailableFonts[i];
    // don't try to load cmaps for downloadable fonts not yet loaded
    if (!fe || fe->mIsUserFontContainer) {
      continue;
    }
    fe->ReadCMAP(aFontInfoData);
    mFamilyCharacterMap.Union(*(fe->mCharacterMap));
  }
  mFamilyCharacterMap.Compact();
  mFamilyCharacterMapInitialized = true;
}

void gfxFontFamily::AddSizeOfExcludingThis(MallocSizeOf aMallocSizeOf,
                                           FontListSizes* aSizes) const {
  aSizes->mFontListSize += mName.SizeOfExcludingThisIfUnshared(aMallocSizeOf);
  aSizes->mCharMapsSize +=
      mFamilyCharacterMap.SizeOfExcludingThis(aMallocSizeOf);

  aSizes->mFontListSize +=
      mAvailableFonts.ShallowSizeOfExcludingThis(aMallocSizeOf);
  for (uint32_t i = 0; i < mAvailableFonts.Length(); ++i) {
    gfxFontEntry* fe = mAvailableFonts[i];
    if (fe) {
      fe->AddSizeOfIncludingThis(aMallocSizeOf, aSizes);
    }
  }
}

void gfxFontFamily::AddSizeOfIncludingThis(MallocSizeOf aMallocSizeOf,
                                           FontListSizes* aSizes) const {
  aSizes->mFontListSize += aMallocSizeOf(this);
  AddSizeOfExcludingThis(aMallocSizeOf, aSizes);
}