gecko/gfx/thebes/gfxDWriteFontList.cpp

/* -*- 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/. */

#include "mozilla/ArrayUtils.h"
#include "mozilla/MemoryReporting.h"

#ifdef MOZ_LOGGING
#define FORCE_PR_LOG /* Allow logging in the release build */
#endif /* MOZ_LOGGING */

#include "gfxDWriteFontList.h"
#include "gfxDWriteFonts.h"
#include "nsUnicharUtils.h"
#include "nsILocaleService.h"
#include "nsServiceManagerUtils.h"
#include "nsCharSeparatedTokenizer.h"
#include "mozilla/Preferences.h"
#include "mozilla/Telemetry.h"

#include "gfxGDIFontList.h"

#include "nsIWindowsRegKey.h"

#include "harfbuzz/hb.h"

using namespace mozilla;

#define LOG_FONTLIST(args) PR_LOG(gfxPlatform::GetLog(eGfxLog_fontlist), \
                               PR_LOG_DEBUG, args)
#define LOG_FONTLIST_ENABLED() PR_LOG_TEST( \
                                   gfxPlatform::GetLog(eGfxLog_fontlist), \
                                   PR_LOG_DEBUG)

#define LOG_FONTINIT(args) PR_LOG(gfxPlatform::GetLog(eGfxLog_fontinit), \
                               PR_LOG_DEBUG, args)
#define LOG_FONTINIT_ENABLED() PR_LOG_TEST( \
                                   gfxPlatform::GetLog(eGfxLog_fontinit), \
                                   PR_LOG_DEBUG)

#define LOG_CMAPDATA_ENABLED() PR_LOG_TEST( \
                                   gfxPlatform::GetLog(eGfxLog_cmapdata), \
                                   PR_LOG_DEBUG)

static __inline void
BuildKeyNameFromFontName(nsAString &aName)
{
    if (aName.Length() >= LF_FACESIZE)
        aName.Truncate(LF_FACESIZE - 1);
    ToLowerCase(aName);
}

////////////////////////////////////////////////////////////////////////////////
// gfxDWriteFontFamily

gfxDWriteFontFamily::~gfxDWriteFontFamily()
{
}

static HRESULT
GetDirectWriteFontName(IDWriteFont *aFont, nsAString& aFontName)
{
    HRESULT hr;

    nsRefPtr<IDWriteLocalizedStrings> names;
    hr = aFont->GetFaceNames(getter_AddRefs(names));
    if (FAILED(hr)) {
        return hr;
    }

    BOOL exists;
    nsAutoTArray<wchar_t,32> faceName;
    UINT32 englishIdx = 0;
    hr = names->FindLocaleName(L"en-us", &englishIdx, &exists);
    if (FAILED(hr)) {
        return hr;
    }

    if (!exists) {
        // No english found, use whatever is first in the list.
        englishIdx = 0;
    }
    UINT32 length;
    hr = names->GetStringLength(englishIdx, &length);
    if (FAILED(hr)) {
        return hr;
    }
    faceName.SetLength(length + 1);
    hr = names->GetString(englishIdx, faceName.Elements(), length + 1);
    if (FAILED(hr)) {
        return hr;
    }

    aFontName.Assign(faceName.Elements());
    return S_OK;
}

// These strings are only defined in Win SDK 8+, so use #ifdef for now
#if MOZ_WINSDK_TARGETVER > 0x08000000
#define FULLNAME_ID   DWRITE_INFORMATIONAL_STRING_FULL_NAME
#define PSNAME_ID     DWRITE_INFORMATIONAL_STRING_POSTSCRIPT_NAME
#else
#define FULLNAME_ID   DWRITE_INFORMATIONAL_STRING_ID(DWRITE_INFORMATIONAL_STRING_SAMPLE_TEXT + 1)
#define PSNAME_ID     DWRITE_INFORMATIONAL_STRING_ID(DWRITE_INFORMATIONAL_STRING_SAMPLE_TEXT + 2)
#endif

// for use in reading postscript or fullname
static HRESULT
GetDirectWriteFaceName(IDWriteFont *aFont,
                       DWRITE_INFORMATIONAL_STRING_ID aWhichName,
                       nsAString& aFontName)
{
    HRESULT hr;

    BOOL exists;
    nsRefPtr<IDWriteLocalizedStrings> infostrings;
    hr = aFont->GetInformationalStrings(aWhichName, getter_AddRefs(infostrings), &exists);
    if (FAILED(hr) || !exists) {
        return E_FAIL;
    }

    nsAutoTArray<wchar_t,32> faceName;
    UINT32 englishIdx = 0;
    hr = infostrings->FindLocaleName(L"en-us", &englishIdx, &exists);
    if (FAILED(hr)) {
        return hr;
    }

    if (!exists) {
        // No english found, use whatever is first in the list.
        englishIdx = 0;
    }
    UINT32 length;
    hr = infostrings->GetStringLength(englishIdx, &length);
    if (FAILED(hr)) {
        return hr;
    }
    faceName.SetLength(length + 1);
    hr = infostrings->GetString(englishIdx, faceName.Elements(), length + 1);
    if (FAILED(hr)) {
        return hr;
    }

    aFontName.Assign(faceName.Elements());
    return S_OK;
}

void
gfxDWriteFontFamily::FindStyleVariations()
{
    HRESULT hr;
    if (mHasStyles) {
        return;
    }
    mHasStyles = true;

    gfxPlatformFontList *fp = gfxPlatformFontList::PlatformFontList();

    bool skipFaceNames = mFaceNamesInitialized ||
                         !fp->NeedFullnamePostscriptNames();

    for (UINT32 i = 0; i < mDWFamily->GetFontCount(); i++) {
        nsRefPtr<IDWriteFont> font;
        hr = mDWFamily->GetFont(i, getter_AddRefs(font));
        if (FAILED(hr)) {
            // This should never happen.
            NS_WARNING("Failed to get existing font from family.");
            continue;
        }

        if (font->GetSimulations() & DWRITE_FONT_SIMULATIONS_OBLIQUE) {
            // We don't want these.
            continue;
        }

        // name
        nsString fullID(mName);
        nsAutoString faceName;
        hr = GetDirectWriteFontName(font, faceName);
        if (FAILED(hr)) {
            continue;
        }
        fullID.Append(NS_LITERAL_STRING(" "));
        fullID.Append(faceName);

        gfxDWriteFontEntry *fe = new gfxDWriteFontEntry(fullID, font);
        fe->SetForceGDIClassic(mForceGDIClassic);
        AddFontEntry(fe);

        // postscript/fullname if needed
        nsAutoString psname, fullname;
        if (!skipFaceNames) {
            hr = GetDirectWriteFaceName(font, PSNAME_ID, psname);
            if (FAILED(hr)) {
                skipFaceNames = true;
            } else if (psname.Length() > 0) {
                fp->AddPostscriptName(fe, psname);
            }

            hr = GetDirectWriteFaceName(font, FULLNAME_ID, fullname);
            if (FAILED(hr)) {
                skipFaceNames = true;
            } else if (fullname.Length() > 0) {
                fp->AddFullname(fe, fullname);
            }
        }

#ifdef PR_LOGGING
        if (LOG_FONTLIST_ENABLED()) {
            LOG_FONTLIST(("(fontlist) added (%s) to family (%s)"
                 " with style: %s weight: %d stretch: %d psname: %s fullname: %s",
                 NS_ConvertUTF16toUTF8(fe->Name()).get(),
                 NS_ConvertUTF16toUTF8(Name()).get(),
                 (fe->IsItalic()) ? "italic" : "normal",
                 fe->Weight(), fe->Stretch(),
                 NS_ConvertUTF16toUTF8(psname).get(),
                 NS_ConvertUTF16toUTF8(fullname).get()));
        }
#endif
    }

    // assume that if no error, all postscript/fullnames were initialized
    if (!skipFaceNames) {
        mFaceNamesInitialized = true;
    }

    if (!mAvailableFonts.Length()) {
        NS_WARNING("Family with no font faces in it.");
    }

    if (mIsBadUnderlineFamily) {
        SetBadUnderlineFonts();
    }
}

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

    // DirectWrite version of this will try to read
    // postscript/fullnames via DirectWrite API
    FindStyleVariations();

    // fallback to looking up via name table
    if (!mOtherFamilyNamesInitialized || !mFaceNamesInitialized) {
        gfxFontFamily::ReadFaceNames(aPlatformFontList,
                                     aNeedFullnamePostscriptNames);
    }
}

void
gfxDWriteFontFamily::LocalizedName(nsAString &aLocalizedName)
{
    aLocalizedName.AssignLiteral("Unknown Font");
    HRESULT hr;
    nsresult rv;
    nsCOMPtr<nsILocaleService> ls = do_GetService(NS_LOCALESERVICE_CONTRACTID,
                                                  &rv);
    nsCOMPtr<nsILocale> locale;
    rv = ls->GetApplicationLocale(getter_AddRefs(locale));
    nsString localeName;
    if (NS_SUCCEEDED(rv)) {
        rv = locale->GetCategory(NS_LITERAL_STRING(NSILOCALE_MESSAGE), 
                                 localeName);
    }
    if (NS_FAILED(rv)) {
        localeName.AssignLiteral("en-us");
    }

    nsRefPtr<IDWriteLocalizedStrings> names;

    hr = mDWFamily->GetFamilyNames(getter_AddRefs(names));
    if (FAILED(hr)) {
        return;
    }
    UINT32 idx = 0;
    BOOL exists;
    hr = names->FindLocaleName(localeName.BeginReading(),
                               &idx,
                               &exists);
    if (FAILED(hr)) {
        return;
    }
    if (!exists) {
        // Use english is localized is not found.
        hr = names->FindLocaleName(L"en-us", &idx, &exists);
        if (FAILED(hr)) {
            return;
        }
        if (!exists) {
            // Use 0 index if english is not found.
            idx = 0;
        }
    }
    nsAutoTArray<WCHAR, 32> famName;
    UINT32 length;
    
    hr = names->GetStringLength(idx, &length);
    if (FAILED(hr)) {
        return;
    }
    
    if (!famName.SetLength(length + 1)) {
        // Eeep - running out of memory. Unlikely to end well.
        return;
    }

    hr = names->GetString(idx, famName.Elements(), length + 1);
    if (FAILED(hr)) {
        return;
    }

    aLocalizedName = nsDependentString(famName.Elements());
}

void
gfxDWriteFontFamily::AddSizeOfExcludingThis(MallocSizeOf aMallocSizeOf,
                                            FontListSizes* aSizes) const
{
    gfxFontFamily::AddSizeOfExcludingThis(aMallocSizeOf, aSizes);
    // TODO:
    // This doesn't currently account for |mDWFamily|
}

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

////////////////////////////////////////////////////////////////////////////////
// gfxDWriteFontEntry

gfxDWriteFontEntry::~gfxDWriteFontEntry()
{
}

bool
gfxDWriteFontEntry::IsSymbolFont()
{
    if (mFont) {
        return mFont->IsSymbolFont();
    } else {
        return false;
    }
}

static bool
UsingArabicOrHebrewScriptSystemLocale()
{
    LANGID langid = PRIMARYLANGID(::GetSystemDefaultLangID());
    switch (langid) {
    case LANG_ARABIC:
    case LANG_DARI:
    case LANG_PASHTO:
    case LANG_PERSIAN:
    case LANG_SINDHI:
    case LANG_UIGHUR:
    case LANG_URDU:
    case LANG_HEBREW:
        return true;
    default:
        return false;
    }
}

nsresult
gfxDWriteFontEntry::CopyFontTable(uint32_t aTableTag,
                                  FallibleTArray<uint8_t> &aBuffer)
{
    gfxDWriteFontList *pFontList = gfxDWriteFontList::PlatformFontList();

    // Don't use GDI table loading for symbol fonts or for
    // italic fonts in Arabic-script system locales because of
    // potential cmap discrepancies, see bug 629386.
    // Ditto for Hebrew, bug 837498.
    if (mFont && pFontList->UseGDIFontTableAccess() &&
        !(mItalic && UsingArabicOrHebrewScriptSystemLocale()) &&
        !mFont->IsSymbolFont())
    {
        LOGFONTW logfont = { 0 };
        if (!InitLogFont(mFont, &logfont))
            return NS_ERROR_FAILURE;

        AutoDC dc;
        AutoSelectFont font(dc.GetDC(), &logfont);
        if (font.IsValid()) {
            uint32_t tableSize =
                ::GetFontData(dc.GetDC(),
                              NativeEndian::swapToBigEndian(aTableTag), 0,
                              nullptr, 0);
            if (tableSize != GDI_ERROR) {
                if (aBuffer.SetLength(tableSize)) {
                    ::GetFontData(dc.GetDC(),
                                  NativeEndian::swapToBigEndian(aTableTag), 0,
                                  aBuffer.Elements(), aBuffer.Length());
                    return NS_OK;
                }
                return NS_ERROR_OUT_OF_MEMORY;
            }
        }
        return NS_ERROR_FAILURE;
    }

    nsRefPtr<IDWriteFontFace> fontFace;
    nsresult rv = CreateFontFace(getter_AddRefs(fontFace));
    if (NS_FAILED(rv)) {
        return rv;
    }

    uint8_t *tableData;
    uint32_t len;
    void *tableContext = nullptr;
    BOOL exists;
    HRESULT hr =
        fontFace->TryGetFontTable(NativeEndian::swapToBigEndian(aTableTag),
                                  (const void**)&tableData, &len,
                                  &tableContext, &exists);
    if (FAILED(hr) || !exists) {
        return NS_ERROR_FAILURE;
    }

    if (aBuffer.SetLength(len)) {
        memcpy(aBuffer.Elements(), tableData, len);
        rv = NS_OK;
    } else {
        rv = NS_ERROR_OUT_OF_MEMORY;
    }

    if (tableContext) {
        fontFace->ReleaseFontTable(&tableContext);
    }

    return rv;
}

// Access to font tables packaged in hb_blob_t form

// object attached to the Harfbuzz blob, used to release
// the table when the blob is destroyed
class FontTableRec {
public:
    FontTableRec(IDWriteFontFace *aFontFace, void *aContext)
        : mFontFace(aFontFace), mContext(aContext)
    { }

    ~FontTableRec() {
        mFontFace->ReleaseFontTable(mContext);
    }

private:
    IDWriteFontFace *mFontFace;
    void            *mContext;
};

static void
DestroyBlobFunc(void* aUserData)
{
    FontTableRec *ftr = static_cast<FontTableRec*>(aUserData);
    delete ftr;
}

hb_blob_t *
gfxDWriteFontEntry::GetFontTable(uint32_t aTag)
{
    // try to avoid potentially expensive DWrite call if we haven't actually
    // created the font face yet, by using the gfxFontEntry method that will
    // use CopyFontTable and then cache the data
    if (!mFontFace) {
        return gfxFontEntry::GetFontTable(aTag);
    }

    const void *data;
    UINT32      size;
    void       *context;
    BOOL        exists;
    HRESULT hr = mFontFace->TryGetFontTable(NativeEndian::swapToBigEndian(aTag),
                                            &data, &size, &context, &exists);
    if (SUCCEEDED(hr) && exists) {
        FontTableRec *ftr = new FontTableRec(mFontFace, context);
        return hb_blob_create(static_cast<const char*>(data), size,
                              HB_MEMORY_MODE_READONLY,
                              ftr, DestroyBlobFunc);
    }

    return nullptr;
}

nsresult
gfxDWriteFontEntry::ReadCMAP()
{
    nsresult rv;

    // attempt this once, if errors occur leave a blank cmap
    if (mCharacterMap) {
        return NS_OK;
    }

    nsRefPtr<gfxCharacterMap> charmap = new gfxCharacterMap();

    uint32_t kCMAP = TRUETYPE_TAG('c','m','a','p');
    AutoTable cmapTable(this, kCMAP);
    if (cmapTable) {
        bool unicodeFont = false, symbolFont = false; // currently ignored
        uint32_t cmapLen;
        const uint8_t* cmapData =
            reinterpret_cast<const uint8_t*>(hb_blob_get_data(cmapTable,
                                                              &cmapLen));
        rv = gfxFontUtils::ReadCMAP(cmapData, cmapLen,
                                    *charmap, mUVSOffset,
                                    unicodeFont, symbolFont);
    } else {
        rv = NS_ERROR_NOT_AVAILABLE;
    }

    mHasCmapTable = NS_SUCCEEDED(rv);
    if (mHasCmapTable) {
        gfxPlatformFontList *pfl = gfxPlatformFontList::PlatformFontList();
        mCharacterMap = pfl->FindCharMap(charmap);
    } else {
        // if error occurred, initialize to null cmap
        mCharacterMap = new gfxCharacterMap();
    }

#ifdef PR_LOGGING
    LOG_FONTLIST(("(fontlist-cmap) name: %s, size: %d hash: %8.8x%s\n",
                  NS_ConvertUTF16toUTF8(mName).get(),
                  charmap->SizeOfIncludingThis(moz_malloc_size_of),
                  charmap->mHash, mCharacterMap == charmap ? " new" : ""));
    if (LOG_CMAPDATA_ENABLED()) {
        char prefix[256];
        sprintf(prefix, "(cmapdata) name: %.220s",
                NS_ConvertUTF16toUTF8(mName).get());
        charmap->Dump(prefix, eGfxLog_cmapdata);
    }
#endif

    return rv;
}

gfxFont *
gfxDWriteFontEntry::CreateFontInstance(const gfxFontStyle* aFontStyle,
                                       bool aNeedsBold)
{
    return new gfxDWriteFont(this, aFontStyle, aNeedsBold);
}

nsresult
gfxDWriteFontEntry::CreateFontFace(IDWriteFontFace **aFontFace,
                                   DWRITE_FONT_SIMULATIONS aSimulations)
{
    // initialize mFontFace if this hasn't been done before
    if (!mFontFace) {
        HRESULT hr;
        if (mFont) {
            hr = mFont->CreateFontFace(getter_AddRefs(mFontFace));
        } else if (mFontFile) {
            IDWriteFontFile *fontFile = mFontFile.get();
            hr = gfxWindowsPlatform::GetPlatform()->GetDWriteFactory()->
                CreateFontFace(mFaceType,
                               1,
                               &fontFile,
                               0,
                               DWRITE_FONT_SIMULATIONS_NONE,
                               getter_AddRefs(mFontFace));
        } else {
            NS_NOTREACHED("invalid font entry");
            return NS_ERROR_FAILURE;
        }
        if (FAILED(hr)) {
            return NS_ERROR_FAILURE;
        }
    }

    // check whether we need to add a DWrite simulated style
    if ((aSimulations & DWRITE_FONT_SIMULATIONS_BOLD) &&
        !(mFontFace->GetSimulations() & DWRITE_FONT_SIMULATIONS_BOLD)) {
        // if so, we need to return not mFontFace itself but a version that
        // has the Bold simulation - unfortunately, DWrite doesn't provide
        // a simple API for this
        UINT32 numberOfFiles = 0;
        if (FAILED(mFontFace->GetFiles(&numberOfFiles, nullptr))) {
            return NS_ERROR_FAILURE;
        }
        nsAutoTArray<IDWriteFontFile*,1> files;
        files.AppendElements(numberOfFiles);
        if (FAILED(mFontFace->GetFiles(&numberOfFiles, files.Elements()))) {
            return NS_ERROR_FAILURE;
        }
        HRESULT hr = gfxWindowsPlatform::GetPlatform()->GetDWriteFactory()->
            CreateFontFace(mFontFace->GetType(),
                           numberOfFiles,
                           files.Elements(),
                           mFontFace->GetIndex(),
                           aSimulations,
                           aFontFace);
        for (UINT32 i = 0; i < numberOfFiles; ++i) {
            files[i]->Release();
        }
        return FAILED(hr) ? NS_ERROR_FAILURE : NS_OK;
    }

    // no simulation: we can just add a reference to mFontFace and return that
    *aFontFace = mFontFace;
    (*aFontFace)->AddRef();
    return NS_OK;
}

bool
gfxDWriteFontEntry::InitLogFont(IDWriteFont *aFont, LOGFONTW *aLogFont)
{
    HRESULT hr;

    BOOL isInSystemCollection;
    IDWriteGdiInterop *gdi = 
        gfxDWriteFontList::PlatformFontList()->GetGDIInterop();
    hr = gdi->ConvertFontToLOGFONT(aFont, aLogFont, &isInSystemCollection);
    return (FAILED(hr) ? false : true);
}

bool
gfxDWriteFontEntry::IsCJKFont()
{
    if (mIsCJK != UNINITIALIZED_VALUE) {
        return mIsCJK;
    }

    mIsCJK = false;

    const uint32_t kOS2Tag = TRUETYPE_TAG('O','S','/','2');
    AutoFallibleTArray<uint8_t,128> buffer;
    if (CopyFontTable(kOS2Tag, buffer) != NS_OK) {
        return mIsCJK;
    }

    // ulCodePageRange bit definitions for the CJK codepages,
    // from http://www.microsoft.com/typography/otspec/os2.htm#cpr
    const uint32_t CJK_CODEPAGE_BITS =
        (1 << 17) | // codepage 932 - JIS/Japan
        (1 << 18) | // codepage 936 - Chinese (simplified)
        (1 << 19) | // codepage 949 - Korean Wansung
        (1 << 20) | // codepage 950 - Chinese (traditional)
        (1 << 21);  // codepage 1361 - Korean Johab

    if (buffer.Length() >= offsetof(OS2Table, sxHeight)) {
        const OS2Table* os2 =
            reinterpret_cast<const OS2Table*>(buffer.Elements());
        if ((uint32_t(os2->codePageRange1) & CJK_CODEPAGE_BITS) != 0) {
            mIsCJK = true;
        }
    }

    return mIsCJK;
}

void
gfxDWriteFontEntry::AddSizeOfExcludingThis(MallocSizeOf aMallocSizeOf,
                                           FontListSizes* aSizes) const
{
    gfxFontEntry::AddSizeOfExcludingThis(aMallocSizeOf, aSizes);
    // TODO:
    // This doesn't currently account for the |mFont| and |mFontFile| members
}

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

////////////////////////////////////////////////////////////////////////////////
// gfxDWriteFontList

gfxDWriteFontList::gfxDWriteFontList()
    : mInitialized(false), mForceGDIClassicMaxFontSize(0.0)
{
}

// bug 602792 - CJK systems default to large CJK fonts which cause excessive
//   I/O strain during cold startup due to dwrite caching bugs.  Default to
//   Arial to avoid this.

gfxFontFamily *
gfxDWriteFontList::GetDefaultFont(const gfxFontStyle *aStyle)
{
    nsAutoString resolvedName;

    // try Arial first
    if (ResolveFontName(NS_LITERAL_STRING("Arial"), resolvedName)) {
        return FindFamily(resolvedName);
    }

    // otherwise, use local default
    NONCLIENTMETRICSW ncm;
    ncm.cbSize = sizeof(ncm);
    BOOL status = ::SystemParametersInfoW(SPI_GETNONCLIENTMETRICS, 
                                          sizeof(ncm), &ncm, 0);
    if (status) {
        if (ResolveFontName(nsDependentString(ncm.lfMessageFont.lfFaceName),
                            resolvedName)) {
            return FindFamily(resolvedName);
        }
    }

    return nullptr;
}

gfxFontEntry *
gfxDWriteFontList::LookupLocalFont(const gfxProxyFontEntry *aProxyEntry,
                                   const nsAString& aFullname)
{
    gfxFontEntry *lookup;

    // initialize name lookup tables if needed
    if (!mFaceNamesInitialized) {
        InitFaceNameLists();
    }

    // lookup in name lookup tables, return null if not found
    if (!(lookup = mExtraNames->mPostscriptNames.GetWeak(aFullname)) &&
        !(lookup = mExtraNames->mFullnames.GetWeak(aFullname)))
    {
        return nullptr;
    }
    gfxDWriteFontEntry* dwriteLookup = static_cast<gfxDWriteFontEntry*>(lookup);
    gfxDWriteFontEntry *fe =
        new gfxDWriteFontEntry(lookup->Name(),
                               dwriteLookup->mFont,
                               aProxyEntry->Weight(),
                               aProxyEntry->Stretch(),
                               aProxyEntry->IsItalic());
    fe->SetForceGDIClassic(dwriteLookup->GetForceGDIClassic());
    return fe;
}

gfxFontEntry *
gfxDWriteFontList::MakePlatformFont(const gfxProxyFontEntry *aProxyEntry,
                                    const uint8_t *aFontData,
                                    uint32_t aLength)
{
    nsresult rv;
    nsAutoString uniqueName;
    rv = gfxFontUtils::MakeUniqueUserFontName(uniqueName);
    if (NS_FAILED(rv)) {
        NS_Free((void*)aFontData);
        return nullptr;
    }

    FallibleTArray<uint8_t> newFontData;

    rv = gfxFontUtils::RenameFont(uniqueName, aFontData, aLength, &newFontData);
    NS_Free((void*)aFontData);

    if (NS_FAILED(rv)) {
        return nullptr;
    }
    
    nsRefPtr<IDWriteFontFile> fontFile;
    HRESULT hr;

    /**
     * We pass in a pointer to a structure containing a pointer to the array
     * containing the font data and a unique identifier. DWrite will
     * internally copy what is at that pointer, and pass that to
     * CreateStreamFromKey. The array will be empty when the function 
     * succesfully returns since it swaps out the data.
     */
    ffReferenceKey key;
    key.mArray = &newFontData;
    nsCOMPtr<nsIUUIDGenerator> uuidgen =
      do_GetService("@mozilla.org/uuid-generator;1");
    if (!uuidgen) {
        return nullptr;
    }

    rv = uuidgen->GenerateUUIDInPlace(&key.mGUID);

    if (NS_FAILED(rv)) {
        return nullptr;
    }

    hr = gfxWindowsPlatform::GetPlatform()->GetDWriteFactory()->
        CreateCustomFontFileReference(&key,
                                      sizeof(key),
                                      gfxDWriteFontFileLoader::Instance(),
                                      getter_AddRefs(fontFile));

    if (FAILED(hr)) {
        NS_WARNING("Failed to create custom font file reference.");
        return nullptr;
    }

    BOOL isSupported;
    DWRITE_FONT_FILE_TYPE fileType;
    UINT32 numFaces;

    gfxDWriteFontEntry *entry = 
        new gfxDWriteFontEntry(uniqueName, 
                               fontFile,
                               aProxyEntry->Weight(),
                               aProxyEntry->Stretch(),
                               aProxyEntry->IsItalic());

    fontFile->Analyze(&isSupported, &fileType, &entry->mFaceType, &numFaces);
    if (!isSupported || numFaces > 1) {
        // We don't know how to deal with 0 faces either.
        delete entry;
        return nullptr;
    }

    return entry;
}

#ifdef DEBUG_DWRITE_STARTUP

#define LOGREGISTRY(msg) LogRegistryEvent(msg)

// for use when monitoring process
static void LogRegistryEvent(const wchar_t *msg)
{
    HKEY dummyKey;
    HRESULT hr;
    wchar_t buf[512];

    wsprintfW(buf, L" log %s", msg);
    hr = RegOpenKeyExW(HKEY_LOCAL_MACHINE, buf, 0, KEY_READ, &dummyKey);
    if (SUCCEEDED(hr)) {
        RegCloseKey(dummyKey);
    }
}
#else

#define LOGREGISTRY(msg)

#endif

nsresult
gfxDWriteFontList::InitFontList()
{
    LOGREGISTRY(L"InitFontList start");

    mInitialized = false;

    LARGE_INTEGER frequency;        // ticks per second
    LARGE_INTEGER t1, t2, t3;           // ticks
    double elapsedTime, upTime;
    char nowTime[256], nowDate[256];

    if (LOG_FONTINIT_ENABLED()) {    
        GetTimeFormat(LOCALE_INVARIANT, TIME_FORCE24HOURFORMAT, 
                      nullptr, nullptr, nowTime, 256);
        GetDateFormat(LOCALE_INVARIANT, 0, nullptr, nullptr, nowDate, 256);
    }
    upTime = (double) GetTickCount();
    QueryPerformanceFrequency(&frequency);
    QueryPerformanceCounter(&t1);

    HRESULT hr;
    gfxFontCache *fc = gfxFontCache::GetCache();
    if (fc) {
        fc->AgeAllGenerations();
    }

    mGDIFontTableAccess = Preferences::GetBool("gfx.font_rendering.directwrite.use_gdi_table_loading", false);

    gfxPlatformFontList::InitFontList();

    mFontSubstitutes.Clear();
    mNonExistingFonts.Clear();

    QueryPerformanceCounter(&t2);

    hr = gfxWindowsPlatform::GetPlatform()->GetDWriteFactory()->
        GetGdiInterop(getter_AddRefs(mGDIInterop));
    if (FAILED(hr)) {
        return NS_ERROR_FAILURE;
    }

    LOGREGISTRY(L"InitFontList end");

    QueryPerformanceCounter(&t3);

    if (LOG_FONTINIT_ENABLED()) {
        // determine dwrite version
        nsAutoString dwriteVers;
        gfxWindowsPlatform::GetDLLVersion(L"dwrite.dll", dwriteVers);
        LOG_FONTINIT(("InitFontList\n"));
        LOG_FONTINIT(("Start: %s %s\n", nowDate, nowTime));
        LOG_FONTINIT(("Uptime: %9.3f s\n", upTime/1000));
        LOG_FONTINIT(("dwrite version: %s\n", 
                      NS_ConvertUTF16toUTF8(dwriteVers).get()));
    }

    elapsedTime = (t3.QuadPart - t1.QuadPart) * 1000.0 / frequency.QuadPart;
    Telemetry::Accumulate(Telemetry::DWRITEFONT_INITFONTLIST_TOTAL, elapsedTime);
    LOG_FONTINIT(("Total time in InitFontList:    %9.3f ms\n", elapsedTime));
    elapsedTime = (t2.QuadPart - t1.QuadPart) * 1000.0 / frequency.QuadPart;
    Telemetry::Accumulate(Telemetry::DWRITEFONT_INITFONTLIST_INIT, elapsedTime);
    LOG_FONTINIT((" --- gfxPlatformFontList init: %9.3f ms\n", elapsedTime));
    elapsedTime = (t3.QuadPart - t2.QuadPart) * 1000.0 / frequency.QuadPart;
    Telemetry::Accumulate(Telemetry::DWRITEFONT_INITFONTLIST_GDI, elapsedTime);
    LOG_FONTINIT((" --- GdiInterop object:        %9.3f ms\n", elapsedTime));

    return NS_OK;
}

nsresult
gfxDWriteFontList::DelayedInitFontList()
{
    LOGREGISTRY(L"DelayedInitFontList start");

    LARGE_INTEGER frequency;        // ticks per second
    LARGE_INTEGER t1, t2, t3;           // ticks
    double elapsedTime, upTime;
    char nowTime[256], nowDate[256];

    if (LOG_FONTINIT_ENABLED()) {    
        GetTimeFormat(LOCALE_INVARIANT, TIME_FORCE24HOURFORMAT, 
                      nullptr, nullptr, nowTime, 256);
        GetDateFormat(LOCALE_INVARIANT, 0, nullptr, nullptr, nowDate, 256);
    }

    upTime = (double) GetTickCount();
    QueryPerformanceFrequency(&frequency);
    QueryPerformanceCounter(&t1);

    HRESULT hr;

    LOGREGISTRY(L"calling GetSystemFontCollection");
    nsRefPtr<IDWriteFontCollection> systemFonts;
    hr = gfxWindowsPlatform::GetPlatform()->GetDWriteFactory()->
        GetSystemFontCollection(getter_AddRefs(systemFonts));
    NS_ASSERTION(SUCCEEDED(hr), "GetSystemFontCollection failed!");
    LOGREGISTRY(L"GetSystemFontCollection done");

    if (FAILED(hr)) {
        return NS_ERROR_FAILURE;
    }

    QueryPerformanceCounter(&t2);

    for (UINT32 i = 0; i < systemFonts->GetFontFamilyCount(); i++) {
        nsRefPtr<IDWriteFontFamily> family;
        systemFonts->GetFontFamily(i, getter_AddRefs(family));

        nsRefPtr<IDWriteLocalizedStrings> names;
        hr = family->GetFamilyNames(getter_AddRefs(names));
        if (FAILED(hr)) {
            continue;
        }

        UINT32 englishIdx = 0;

        BOOL exists;
        hr = names->FindLocaleName(L"en-us", &englishIdx, &exists);
        if (FAILED(hr)) {
            continue;
        }
        if (!exists) {
            // Use 0 index if english is not found.
            englishIdx = 0;
        }

        nsAutoTArray<WCHAR, 32> enName;
        UINT32 length;
        
        hr = names->GetStringLength(englishIdx, &length);
        if (FAILED(hr)) {
            continue;
        }
        
        if (!enName.SetLength(length + 1)) {
            // Eeep - running out of memory. Unlikely to end well.
            continue;
        }

        hr = names->GetString(englishIdx, enName.Elements(), length + 1);
        if (FAILED(hr)) {
            continue;
        }

        nsAutoString name(enName.Elements());
        BuildKeyNameFromFontName(name);

        nsRefPtr<gfxFontFamily> fam;

        if (mFontFamilies.GetWeak(name)) {
            continue;
        }
        
        nsDependentString familyName(enName.Elements());

        fam = new gfxDWriteFontFamily(familyName, family);
        if (!fam) {
            continue;
        }

        if (mBadUnderlineFamilyNames.Contains(name)) {
            fam->SetBadUnderlineFamily();
        }
        mFontFamilies.Put(name, fam);

        // now add other family name localizations, if present
        uint32_t nameCount = names->GetCount();
        uint32_t nameIndex;

        for (nameIndex = 0; nameIndex < nameCount; nameIndex++) {
            UINT32 nameLen;
            nsAutoTArray<WCHAR, 32> localizedName;

            // only add other names
            if (nameIndex == englishIdx) {
                continue;
            }
            
            hr = names->GetStringLength(nameIndex, &nameLen);
            if (FAILED(hr)) {
                continue;
            }

            if (!localizedName.SetLength(nameLen + 1)) {
                continue;
            }

            hr = names->GetString(nameIndex, localizedName.Elements(), 
                                  nameLen + 1);
            if (FAILED(hr)) {
                continue;
            }

            nsDependentString locName(localizedName.Elements());

            if (!familyName.Equals(locName)) {
                AddOtherFamilyName(fam, locName);
            }

        }

        // at this point, all family names have been read in
        fam->SetOtherFamilyNamesInitialized();
    }

    mOtherFamilyNamesInitialized = true;
    GetFontSubstitutes();

    // bug 642093 - DirectWrite does not support old bitmap (.fon)
    // font files, but a few of these such as "Courier" and "MS Sans Serif"
    // are frequently specified in shoddy CSS, without appropriate fallbacks.
    // By mapping these to TrueType equivalents, we provide better consistency
    // with both pre-DW systems and with IE9, which appears to do the same.
    GetDirectWriteSubstitutes();

    // bug 551313 - DirectWrite creates a Gill Sans family out of 
    // poorly named members of the Gill Sans MT family containing
    // only Ultra Bold weights.  This causes big problems for pages
    // using Gill Sans which is usually only available on OSX

    nsAutoString nameGillSans(L"Gill Sans");
    nsAutoString nameGillSansMT(L"Gill Sans MT");
    BuildKeyNameFromFontName(nameGillSans);
    BuildKeyNameFromFontName(nameGillSansMT);

    gfxFontFamily *gillSansFamily = mFontFamilies.GetWeak(nameGillSans);
    gfxFontFamily *gillSansMTFamily = mFontFamilies.GetWeak(nameGillSansMT);

    if (gillSansFamily && gillSansMTFamily) {
        gillSansFamily->FindStyleVariations();
        nsTArray<nsRefPtr<gfxFontEntry> >& faces = gillSansFamily->GetFontList();
        uint32_t i;

        bool allUltraBold = true;
        for (i = 0; i < faces.Length(); i++) {
            // does the face have 'Ultra Bold' in the name?
            if (faces[i]->Name().Find(NS_LITERAL_STRING("Ultra Bold")) == -1) {
                allUltraBold = false;
                break;
            }
        }

        // if all the Gill Sans faces are Ultra Bold ==> move faces
        // for Gill Sans into Gill Sans MT family
        if (allUltraBold) {

            // add faces to Gill Sans MT
            for (i = 0; i < faces.Length(); i++) {
                gillSansMTFamily->AddFontEntry(faces[i]);

#ifdef PR_LOGGING
                if (LOG_FONTLIST_ENABLED()) {
                    gfxFontEntry *fe = faces[i];
                    LOG_FONTLIST(("(fontlist) moved (%s) to family (%s)"
                         " with style: %s weight: %d stretch: %d",
                         NS_ConvertUTF16toUTF8(fe->Name()).get(),
                         NS_ConvertUTF16toUTF8(gillSansMTFamily->Name()).get(),
                         (fe->IsItalic()) ? "italic" : "normal",
                         fe->Weight(), fe->Stretch()));
                }
#endif
            }

            // remove Gills Sans
            mFontFamilies.Remove(nameGillSans);
        }
    }

    nsAdoptingCString classicFamilies =
        Preferences::GetCString("gfx.font_rendering.cleartype_params.force_gdi_classic_for_families");
    if (classicFamilies) {
        nsCCharSeparatedTokenizer tokenizer(classicFamilies, ',');
        while (tokenizer.hasMoreTokens()) {
            NS_ConvertUTF8toUTF16 name(tokenizer.nextToken());
            BuildKeyNameFromFontName(name);
            gfxFontFamily *family = mFontFamilies.GetWeak(name);
            if (family) {
                static_cast<gfxDWriteFontFamily*>(family)->SetForceGDIClassic(true);
            }
        }
    }
    mForceGDIClassicMaxFontSize =
        Preferences::GetInt("gfx.font_rendering.cleartype_params.force_gdi_classic_max_size",
                            mForceGDIClassicMaxFontSize);

    GetPrefsAndStartLoader();

    LOGREGISTRY(L"DelayedInitFontList end");

    QueryPerformanceCounter(&t3);

    if (LOG_FONTINIT_ENABLED()) {
        // determine dwrite version
        nsAutoString dwriteVers;
        gfxWindowsPlatform::GetDLLVersion(L"dwrite.dll", dwriteVers);
        LOG_FONTINIT(("DelayedInitFontList\n"));
        LOG_FONTINIT(("Start: %s %s\n", nowDate, nowTime));
        LOG_FONTINIT(("Uptime: %9.3f s\n", upTime/1000));
        LOG_FONTINIT(("dwrite version: %s\n", 
                      NS_ConvertUTF16toUTF8(dwriteVers).get()));
    }

    elapsedTime = (t3.QuadPart - t1.QuadPart) * 1000.0 / frequency.QuadPart;
    Telemetry::Accumulate(Telemetry::DWRITEFONT_DELAYEDINITFONTLIST_TOTAL, elapsedTime);
    Telemetry::Accumulate(Telemetry::DWRITEFONT_DELAYEDINITFONTLIST_COUNT,
                          systemFonts->GetFontFamilyCount());
    Telemetry::Accumulate(Telemetry::DWRITEFONT_DELAYEDINITFONTLIST_GDI_TABLE, mGDIFontTableAccess);
    LOG_FONTINIT((
       "Total time in DelayedInitFontList:    %9.3f ms (families: %d, %s)\n",
       elapsedTime, systemFonts->GetFontFamilyCount(),
       (mGDIFontTableAccess ? "gdi table access" : "dwrite table access")));

    elapsedTime = (t2.QuadPart - t1.QuadPart) * 1000.0 / frequency.QuadPart;
    Telemetry::Accumulate(Telemetry::DWRITEFONT_DELAYEDINITFONTLIST_COLLECT, elapsedTime);
    LOG_FONTINIT((" --- GetSystemFontCollection:  %9.3f ms\n", elapsedTime));

    elapsedTime = (t3.QuadPart - t2.QuadPart) * 1000.0 / frequency.QuadPart;
    Telemetry::Accumulate(Telemetry::DWRITEFONT_DELAYEDINITFONTLIST_ITERATE, elapsedTime);
    LOG_FONTINIT((" --- iterate over families:    %9.3f ms\n", elapsedTime));

    return NS_OK;
}

static void
RemoveCharsetFromFontSubstitute(nsAString &aName)
{
    int32_t comma = aName.FindChar(PRUnichar(','));
    if (comma >= 0)
        aName.Truncate(comma);
}

#define MAX_VALUE_NAME 512
#define MAX_VALUE_DATA 512

nsresult
gfxDWriteFontList::GetFontSubstitutes()
{
    HKEY hKey;
    DWORD i, rv, lenAlias, lenActual, valueType;
    WCHAR aliasName[MAX_VALUE_NAME];
    WCHAR actualName[MAX_VALUE_DATA];

    if (RegOpenKeyExW(HKEY_LOCAL_MACHINE, 
          L"SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\FontSubstitutes",
          0, KEY_READ, &hKey) != ERROR_SUCCESS)
    {
        return NS_ERROR_FAILURE;
    }

    for (i = 0, rv = ERROR_SUCCESS; rv != ERROR_NO_MORE_ITEMS; i++) {
        aliasName[0] = 0;
        lenAlias = ArrayLength(aliasName);
        actualName[0] = 0;
        lenActual = sizeof(actualName);
        rv = RegEnumValueW(hKey, i, aliasName, &lenAlias, nullptr, &valueType,
                (LPBYTE)actualName, &lenActual);

        if (rv != ERROR_SUCCESS || valueType != REG_SZ || lenAlias == 0) {
            continue;
        }

        if (aliasName[0] == WCHAR('@')) {
            continue;
        }

        nsAutoString substituteName((PRUnichar*) aliasName);
        nsAutoString actualFontName((PRUnichar*) actualName);
        RemoveCharsetFromFontSubstitute(substituteName);
        BuildKeyNameFromFontName(substituteName);
        RemoveCharsetFromFontSubstitute(actualFontName);
        BuildKeyNameFromFontName(actualFontName);
        gfxFontFamily *ff;
        if (!actualFontName.IsEmpty() && 
            (ff = mFontFamilies.GetWeak(actualFontName))) {
            mFontSubstitutes.Put(substituteName, ff);
        } else {
            mNonExistingFonts.AppendElement(substituteName);
        }
    }
    return NS_OK;
}

struct FontSubstitution {
    const WCHAR* aliasName;
    const WCHAR* actualName;
};

static const FontSubstitution sDirectWriteSubs[] = {
    { L"MS Sans Serif", L"Microsoft Sans Serif" },
    { L"MS Serif", L"Times New Roman" },
    { L"Courier", L"Courier New" },
    { L"Small Fonts", L"Arial" },
    { L"Roman", L"Times New Roman" },
    { L"Script", L"Mistral" }
};

void
gfxDWriteFontList::GetDirectWriteSubstitutes()
{
    for (uint32_t i = 0; i < ArrayLength(sDirectWriteSubs); ++i) {
        const FontSubstitution& sub(sDirectWriteSubs[i]);
        nsAutoString substituteName((PRUnichar*)sub.aliasName);
        BuildKeyNameFromFontName(substituteName);
        if (nullptr != mFontFamilies.GetWeak(substituteName)) {
            // don't do the substitution if user actually has a usable font
            // with this name installed
            continue;
        }
        nsAutoString actualFontName((PRUnichar*)sub.actualName);
        BuildKeyNameFromFontName(actualFontName);
        gfxFontFamily *ff;
        if (nullptr != (ff = mFontFamilies.GetWeak(actualFontName))) {
            mFontSubstitutes.Put(substituteName, ff);
        } else {
            mNonExistingFonts.AppendElement(substituteName);
        }
    }
}

bool
gfxDWriteFontList::GetStandardFamilyName(const nsAString& aFontName,
                                         nsAString& aFamilyName)
{
    gfxFontFamily *family = FindFamily(aFontName);
    if (family) {
        family->LocalizedName(aFamilyName);
        return true;
    }

    return false;
}

gfxFontFamily* gfxDWriteFontList::FindFamily(const nsAString& aFamily)
{
    if (!mInitialized) {
        mInitialized = true;
        DelayedInitFontList();
    }

    return gfxPlatformFontList::FindFamily(aFamily);
}

void
gfxDWriteFontList::GetFontFamilyList(nsTArray<nsRefPtr<gfxFontFamily> >& aFamilyArray)
{
    if (!mInitialized) {
        mInitialized = true;
        DelayedInitFontList();
    }

    return gfxPlatformFontList::GetFontFamilyList(aFamilyArray);
}

bool 
gfxDWriteFontList::ResolveFontName(const nsAString& aFontName,
                                   nsAString& aResolvedFontName)
{
    if (!mInitialized) {
        mInitialized = true;
        DelayedInitFontList();
    }

    nsAutoString keyName(aFontName);
    BuildKeyNameFromFontName(keyName);

    gfxFontFamily *ff = mFontSubstitutes.GetWeak(keyName);
    if (ff) {
        aResolvedFontName = ff->Name();
        return true;
    }

    if (mNonExistingFonts.Contains(keyName)) {
        return false;
    }

    return gfxPlatformFontList::ResolveFontName(aFontName, aResolvedFontName);
}

void
gfxDWriteFontList::AddSizeOfExcludingThis(MallocSizeOf aMallocSizeOf,
                                          FontListSizes* aSizes) const
{
    gfxPlatformFontList::AddSizeOfExcludingThis(aMallocSizeOf, aSizes);

    aSizes->mFontListSize +=
        mFontSubstitutes.SizeOfExcludingThis(SizeOfFamilyNameEntryExcludingThis,
                                             aMallocSizeOf);

    aSizes->mFontListSize +=
        mNonExistingFonts.SizeOfExcludingThis(aMallocSizeOf);
    for (uint32_t i = 0; i < mNonExistingFonts.Length(); ++i) {
        aSizes->mFontListSize +=
            mNonExistingFonts[i].SizeOfExcludingThisIfUnshared(aMallocSizeOf);
    }
}

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

static HRESULT GetFamilyName(IDWriteFont *aFont, nsString& aFamilyName)
{
    HRESULT hr;
    nsRefPtr<IDWriteFontFamily> family;

    // clean out previous value
    aFamilyName.Truncate();

    hr = aFont->GetFontFamily(getter_AddRefs(family));
    if (FAILED(hr)) {
        return hr;
    }

    nsRefPtr<IDWriteLocalizedStrings> familyNames;

    hr = family->GetFamilyNames(getter_AddRefs(familyNames));
    if (FAILED(hr)) {
        return hr;
    }

    UINT32 index = 0;
    BOOL exists = false;

    hr = familyNames->FindLocaleName(L"en-us", &index, &exists);
    if (FAILED(hr)) {
        return hr;
    }

    // If the specified locale doesn't exist, select the first on the list.
    if (!exists) {
        index = 0;
    }

    nsAutoTArray<WCHAR, 32> name;
    UINT32 length;

    hr = familyNames->GetStringLength(index, &length);
    if (FAILED(hr)) {
        return hr;
    }

    if (!name.SetLength(length + 1)) {
        return E_FAIL;
    }
    hr = familyNames->GetString(index, name.Elements(), length + 1);
    if (FAILED(hr)) {
        return hr;
    }

    aFamilyName.Assign(name.Elements());
    return S_OK;
}

// bug 705594 - the method below doesn't actually do any "drawing", it's only
// used to invoke the DirectWrite layout engine to determine the fallback font
// for a given character.

IFACEMETHODIMP FontFallbackRenderer::DrawGlyphRun(
    void* clientDrawingContext,
    FLOAT baselineOriginX,
    FLOAT baselineOriginY,
    DWRITE_MEASURING_MODE measuringMode,
    DWRITE_GLYPH_RUN const* glyphRun,
    DWRITE_GLYPH_RUN_DESCRIPTION const* glyphRunDescription,
    IUnknown* clientDrawingEffect
    )
{
    if (!mSystemFonts) {
        return E_FAIL;
    }

    HRESULT hr = S_OK;

    nsRefPtr<IDWriteFont> font;
    hr = mSystemFonts->GetFontFromFontFace(glyphRun->fontFace,
                                           getter_AddRefs(font));
    if (FAILED(hr)) {
        return hr;
    }

    // copy the family name
    hr = GetFamilyName(font, mFamilyName);
    if (FAILED(hr)) {
        return hr;
    }

    // Arial is used as the default fallback font
    // so if it matches ==> no font found
    if (mFamilyName.EqualsLiteral("Arial")) {
        mFamilyName.Truncate();
        return E_FAIL;
    }
    return hr;
}

gfxFontEntry*
gfxDWriteFontList::GlobalFontFallback(const uint32_t aCh,
                                      int32_t aRunScript,
                                      const gfxFontStyle* aMatchStyle,
                                      uint32_t& aCmapCount,
                                      gfxFontFamily** aMatchedFamily)
{
    bool useCmaps = gfxPlatform::GetPlatform()->UseCmapsDuringSystemFallback();

    if (useCmaps) {
        return gfxPlatformFontList::GlobalFontFallback(aCh,
                                                       aRunScript,
                                                       aMatchStyle,
                                                       aCmapCount,
                                                       aMatchedFamily);
    }

    HRESULT hr;

    nsRefPtr<IDWriteFactory> dwFactory =
        gfxWindowsPlatform::GetPlatform()->GetDWriteFactory();
    if (!dwFactory) {
        return nullptr;
    }

    // initialize fallback renderer
    if (!mFallbackRenderer) {
        mFallbackRenderer = new FontFallbackRenderer(dwFactory);
    }

    // initialize text format
    if (!mFallbackFormat) {
        hr = dwFactory->CreateTextFormat(L"Arial", nullptr,
                                         DWRITE_FONT_WEIGHT_REGULAR,
                                         DWRITE_FONT_STYLE_NORMAL,
                                         DWRITE_FONT_STRETCH_NORMAL,
                                         72.0f, L"en-us",
                                         getter_AddRefs(mFallbackFormat));
        if (FAILED(hr)) {
            return nullptr;
        }
    }

    // set up string with fallback character
    wchar_t str[16];
    uint32_t strLen;

    if (IS_IN_BMP(aCh)) {
        str[0] = static_cast<wchar_t> (aCh);
        str[1] = 0;
        strLen = 1;
    } else {
        str[0] = static_cast<wchar_t> (H_SURROGATE(aCh));
        str[1] = static_cast<wchar_t> (L_SURROGATE(aCh));
        str[2] = 0;
        strLen = 2;
    }

    // set up layout
    nsRefPtr<IDWriteTextLayout> fallbackLayout;

    hr = dwFactory->CreateTextLayout(str, strLen, mFallbackFormat,
                                     200.0f, 200.0f,
                                     getter_AddRefs(fallbackLayout));
    if (FAILED(hr)) {
        return nullptr;
    }

    // call the draw method to invoke the DirectWrite layout functions
    // which determine the fallback font
    hr = fallbackLayout->Draw(nullptr, mFallbackRenderer, 50.0f, 50.0f);
    if (FAILED(hr)) {
        return nullptr;
    }

    gfxFontFamily *family = FindFamily(mFallbackRenderer->FallbackFamilyName());
    if (family) {
        gfxFontEntry *fontEntry;
        bool needsBold;  // ignored in the system fallback case
        fontEntry = family->FindFontForStyle(*aMatchStyle, needsBold);
        if (fontEntry && fontEntry->TestCharacterMap(aCh)) {
            *aMatchedFamily = family;
            return fontEntry;
        }
        Telemetry::Accumulate(Telemetry::BAD_FALLBACK_FONT, true);
    }

    return nullptr;
}