[tor-commits] [Git][tpo/applications/tor-browser][tor-browser-140.10.0esr-15.0-1] Bug 2009213 - Use local statics for harfbuzz callback pointers, to ensure...

Pier Angelo Vendrame pushed to branch tor-browser-140.10.0esr-15.0-1 at The Tor Project / Applications / Tor Browser

Commits:

1ca1b1fb

by Jonathan Kew at 2026-04-16T08:41:11+02:00

Bug 2009213 - Use local statics for harfbuzz callback pointers, to ensure thread-safe initialization. r=gfx-reviewers,lsalzman

Differential Revision: https://phabricator.services.mozilla.com/D278945

Changes:

gfx/thebes/gfxHarfBuzzShaper.cpp

@@ -1181,9 +1181,6 @@ static void AddOpenTypeFeature(uint32_t aTag, uint32_t aValue, void* aUserArg) {
   * gfxFontShaper override to initialize the text run using HarfBuzz
   */
 -static hb_font_funcs_t* sHBFontFuncs = nullptr;
 -static hb_font_funcs_t* sNominalGlyphFunc = nullptr;
 -static hb_unicode_funcs_t* sHBUnicodeFuncs = nullptr;
  MOZ_RUNINIT static const hb_script_t sMathScript =
      hb_ot_tag_to_script(HB_TAG('m', 'a', 't', 'h'));
@@ -1192,52 +1189,58 @@ bool gfxHarfBuzzShaper::Initialize() {
    // other thread can yet be using it.
    MOZ_PUSH_IGNORE_THREAD_SAFETY
 -  if (!sHBFontFuncs) {
 -    // static function callback pointers, initialized by the first
 -    // harfbuzz shaper used
 -    sHBFontFuncs = hb_font_funcs_create();
 -    hb_font_funcs_set_nominal_glyph_func(sHBFontFuncs, HBGetNominalGlyph,
 -                                         nullptr, nullptr);
 -    hb_font_funcs_set_nominal_glyphs_func(sHBFontFuncs, HBGetNominalGlyphs,
 -                                          nullptr, nullptr);
 -    hb_font_funcs_set_variation_glyph_func(sHBFontFuncs, HBGetVariationGlyph,
 -                                           nullptr, nullptr);
 -    hb_font_funcs_set_glyph_h_advance_func(sHBFontFuncs, HBGetGlyphHAdvance,
 -                                           nullptr, nullptr);
 -    hb_font_funcs_set_glyph_h_advances_func(sHBFontFuncs, HBGetGlyphHAdvances,
 -                                            nullptr, nullptr);
 -    hb_font_funcs_set_glyph_v_advance_func(sHBFontFuncs, HBGetGlyphVAdvance,
 -                                           nullptr, nullptr);
 -    hb_font_funcs_set_glyph_v_origin_func(sHBFontFuncs, HBGetGlyphVOrigin,
 -                                          nullptr, nullptr);
 -    hb_font_funcs_set_glyph_extents_func(sHBFontFuncs, HBGetGlyphExtents,
 -                                         nullptr, nullptr);
 -    hb_font_funcs_set_glyph_contour_point_func(sHBFontFuncs, HBGetContourPoint,
 +  // Function callback pointers; these are local statics to ensure thread-safe
 +  // initialization on first use.
 +  static hb_font_funcs_t* sHBFontFuncs = [] {
 +    auto* funcs = hb_font_funcs_create();
 +    hb_font_funcs_set_nominal_glyph_func(funcs, HBGetNominalGlyph, nullptr,
 +                                         nullptr);
 +    hb_font_funcs_set_nominal_glyphs_func(funcs, HBGetNominalGlyphs, nullptr,
 +                                          nullptr);
 +    hb_font_funcs_set_variation_glyph_func(funcs, HBGetVariationGlyph, nullptr,
 +                                           nullptr);
 +    hb_font_funcs_set_glyph_h_advance_func(funcs, HBGetGlyphHAdvance, nullptr,
 +                                           nullptr);
 +    hb_font_funcs_set_glyph_h_advances_func(funcs, HBGetGlyphHAdvances, nullptr,
 +                                            nullptr);
 +    hb_font_funcs_set_glyph_v_advance_func(funcs, HBGetGlyphVAdvance, nullptr,
 +                                           nullptr);
 +    hb_font_funcs_set_glyph_v_origin_func(funcs, HBGetGlyphVOrigin, nullptr,
 +                                          nullptr);
 +    hb_font_funcs_set_glyph_extents_func(funcs, HBGetGlyphExtents, nullptr,
 +                                         nullptr);
 +    hb_font_funcs_set_glyph_contour_point_func(funcs, HBGetContourPoint,
                                                 nullptr, nullptr);
 -    hb_font_funcs_set_glyph_h_kerning_func(sHBFontFuncs, HBGetHKerning, nullptr,
 +    hb_font_funcs_set_glyph_h_kerning_func(funcs, HBGetHKerning, nullptr,
                                             nullptr);
 -    hb_font_funcs_make_immutable(sHBFontFuncs);
+-
 -    sNominalGlyphFunc = hb_font_funcs_create();
 -    hb_font_funcs_set_nominal_glyph_func(sNominalGlyphFunc, HBGetNominalGlyph,
 -                                         nullptr, nullptr);
 -    hb_font_funcs_make_immutable(sNominalGlyphFunc);
+-
 -    sHBUnicodeFuncs = hb_unicode_funcs_create(hb_unicode_funcs_get_empty());
 -    hb_unicode_funcs_set_mirroring_func(sHBUnicodeFuncs, HBGetMirroring,
 -                                        nullptr, nullptr);
 -    hb_unicode_funcs_set_script_func(sHBUnicodeFuncs, HBGetScript, nullptr,
 -                                     nullptr);
 -    hb_unicode_funcs_set_general_category_func(
 -        sHBUnicodeFuncs, HBGetGeneralCategory, nullptr, nullptr);
 -    hb_unicode_funcs_set_combining_class_func(
 -        sHBUnicodeFuncs, HBGetCombiningClass, nullptr, nullptr);
 -    hb_unicode_funcs_set_compose_func(sHBUnicodeFuncs, HBUnicodeCompose,
 -                                      nullptr, nullptr);
 -    hb_unicode_funcs_set_decompose_func(sHBUnicodeFuncs, HBUnicodeDecompose,
 -                                        nullptr, nullptr);
 -    hb_unicode_funcs_make_immutable(sHBUnicodeFuncs);
 -  }
 +    hb_font_funcs_make_immutable(funcs);
 +    return funcs;
 +  }();
++
 +  static hb_font_funcs_t* sNominalGlyphFunc = [] {
 +    auto* funcs = hb_font_funcs_create();
 +    hb_font_funcs_set_nominal_glyph_func(funcs, HBGetNominalGlyph, nullptr,
 +                                         nullptr);
 +    hb_font_funcs_make_immutable(funcs);
 +    return funcs;
 +  }();
++
 +  static hb_unicode_funcs_t* sHBUnicodeFuncs = [] {
 +    auto* funcs = hb_unicode_funcs_create(hb_unicode_funcs_get_empty());
 +    hb_unicode_funcs_set_mirroring_func(funcs, HBGetMirroring, nullptr,
 +                                        nullptr);
 +    hb_unicode_funcs_set_script_func(funcs, HBGetScript, nullptr, nullptr);
 +    hb_unicode_funcs_set_general_category_func(funcs, HBGetGeneralCategory,
 +                                               nullptr, nullptr);
 +    hb_unicode_funcs_set_combining_class_func(funcs, HBGetCombiningClass,
 +                                              nullptr, nullptr);
 +    hb_unicode_funcs_set_compose_func(funcs, HBUnicodeCompose, nullptr,
 +                                      nullptr);
 +    hb_unicode_funcs_set_decompose_func(funcs, HBUnicodeDecompose, nullptr,
 +                                        nullptr);
 +    hb_unicode_funcs_make_immutable(funcs);
 +    return funcs;
 +  }();
    gfxFontEntry* entry = mFont->GetFontEntry();
    if (!mUseFontGetGlyph) {
@@ -1280,11 +1283,10 @@ bool gfxHarfBuzzShaper::Initialize() {
    hb_buffer_set_cluster_level(mBuffer,
                                HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS);
 -  auto* funcs =
 -      mFont->GetFontEntry()->HasFontTable(TRUETYPE_TAG('C', 'F', 'F', ' '))
 -          ? sNominalGlyphFunc
 -          : sHBFontFuncs;
 -  mHBFont = CreateHBFont(mFont, funcs, this);
 +  bool isCFF =
 +      mFont->GetFontEntry()->HasFontTable(TRUETYPE_TAG('C', 'F', 'F', ' '));
 +  auto* funcs = isCFF ? sNominalGlyphFunc : sHBFontFuncs;
 +  mHBFont = CreateHBFont(mFont, funcs, this, isCFF);
    MOZ_POP_THREAD_SAFETY
@@ -1293,12 +1295,13 @@ bool gfxHarfBuzzShaper::Initialize() {
  hb_font_t* gfxHarfBuzzShaper::CreateHBFont(gfxFont* aFont,
                                             hb_font_funcs_t* aFontFuncs,
 -                                           void* aCallbackData) {
 +                                           void* aCallbackData,
 +                                           bool aCreateSubfont) {
    auto face(aFont->GetFontEntry()->GetHBFace());
    hb_font_t* result = hb_font_create(face);
    if (aFontFuncs && aCallbackData) {
 -    if (aFontFuncs == sNominalGlyphFunc) {
 +    if (aCreateSubfont) {
        hb_font_t* subfont = hb_font_create_sub_font(result);
        hb_font_destroy(result);
        result = subfont;

gfx/thebes/gfxHarfBuzzShaper.h

@@ -103,7 +103,8 @@ class gfxHarfBuzzShaper : public gfxFontShaper {
    // bounds, etc; if not, the built-in hb_ot font functions will be used.
    static hb_font_t* CreateHBFont(gfxFont* aFont,
                                   hb_font_funcs_t* aFontFuncs = nullptr,
 -                                 void* aCallbackData = nullptr);
 +                                 void* aCallbackData = nullptr,
 +                                 bool aCreateSubfont = false);
   protected:
    // Initializes the shaper and returns whether this was successful.