1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
   55
   56
   57
   58
   59
   60
   61
   62
   63
   64
   65
   66
   67
   68
   69
   70
   71
   72
   73
   74
   75
   76
   77
   78
   79
   80
   81
   82
   83
   84
   85
   86
   87
   88
   89
   90
   91
   92
   93
   94
   95
   96
   97
   98
   99
  100
  101
  102
  103
  104
  105
  106
  107
  108
  109
  110
  111
  112
  113
  114
  115
  116
  117
  118
  119
  120
  121
  122
  123
  124
  125
  126
  127
  128
  129
  130
  131
  132
  133
  134
  135
  136
  137
  138
  139
  140
  141
  142
  143


content / browser / font_access / font_enumeration_data_source_linux.cc [blame]

// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/342213636): Remove this and spanify to fix the errors.
#pragma allow_unsafe_buffers
#endif

#include "content/browser/font_access/font_enumeration_data_source_linux.h"

#include <fontconfig/fontconfig.h>

#include <memory>

#include "base/check_op.h"
#include "base/location.h"
#include "base/notreached.h"
#include "base/sequence_checker.h"
#include "base/task/sequenced_task_runner.h"
#include "base/task/task_traits.h"
#include "base/task/thread_pool.h"
#include "base/threading/scoped_blocking_call.h"
#include "third_party/blink/public/common/font_access/font_enumeration_table.pb.h"

namespace content {

namespace {

std::unique_ptr<FcPattern, decltype(&FcPatternDestroy)> CreateFormatPattern(
    const char* format) {
  std::unique_ptr<FcPattern, decltype(&FcPatternDestroy)> pattern(
      FcPatternCreate(), FcPatternDestroy);
  FcPatternAddBool(pattern.get(), FC_SCALABLE, FcTrue);
  FcPatternAddString(pattern.get(), FC_FONTFORMAT,
                     reinterpret_cast<const FcChar8*>(format));
  return pattern;
}

// Returns a font set comprising of fonts in the provided object set.
FcFontSet* ListFonts(FcObjectSet* object_set) {
  FcFontSet* output = FcFontSetCreate();

  // See https://www.freetype.org/freetype2/docs/reference/ft2-font_formats.html
  // for the list of possible formats.
  const char* allowed_formats[] = {"TrueType", "CFF"};
  for (const auto* format : allowed_formats) {
    auto format_pattern = CreateFormatPattern(format);
    std::unique_ptr<FcFontSet, decltype(&FcFontSetDestroy)> fontset(
        FcFontList(nullptr, format_pattern.get(), object_set),
        FcFontSetDestroy);
    for (int j = 0; j < fontset->nfont; ++j) {
      FcPattern* font = fontset->fonts[j];
      // Increments the refcount for the font.
      FcPatternReference(font);
      FcBool result = FcFontSetAdd(output, font);
      DCHECK_EQ(result, FcTrue);
    }
  }
  return output;
}

}  // namespace

FontEnumerationDataSourceLinux::FontEnumerationDataSourceLinux() {
  DETACH_FROM_SEQUENCE(sequence_checker_);
}

FontEnumerationDataSourceLinux::~FontEnumerationDataSourceLinux() {
  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
}

blink::FontEnumerationTable FontEnumerationDataSourceLinux::GetFonts(
    const std::string& locale) {
  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);

  base::ScopedBlockingCall scoped_blocking_call(FROM_HERE,
                                                base::BlockingType::MAY_BLOCK);

  blink::FontEnumerationTable font_enumeration_table;

  std::unique_ptr<FcObjectSet, decltype(&FcObjectSetDestroy)> object_set(
      FcObjectSetBuild(FC_POSTSCRIPT_NAME, FC_FULLNAME, FC_FAMILY, FC_STYLE,
                       nullptr),
      FcObjectSetDestroy);

  std::unique_ptr<FcFontSet, decltype(&FcFontSetDestroy)> fontset(
      ListFonts(object_set.get()), FcFontSetDestroy);

  // Used to filter duplicates.
  std::set<std::string> fonts_seen;

  for (int i = 0; i < fontset->nfont; ++i) {
    char* postscript_name = nullptr;
    if (FcPatternGetString(fontset->fonts[i], FC_POSTSCRIPT_NAME, 0,
                           reinterpret_cast<FcChar8**>(&postscript_name)) !=
        FcResultMatch) {
      // Skip incomplete or malformed font.
      continue;
    }

    char* full_name = nullptr;
    if (FcPatternGetString(fontset->fonts[i], FC_FULLNAME, 0,
                           reinterpret_cast<FcChar8**>(&full_name)) !=
        FcResultMatch) {
      // Skip incomplete or malformed font.
      continue;
    }

    char* family = nullptr;
    if (FcPatternGetString(fontset->fonts[i], FC_FAMILY, 0,
                           reinterpret_cast<FcChar8**>(&family)) !=
        FcResultMatch) {
      // Skip incomplete or malformed font.
      continue;
    }

    char* style = nullptr;
    if (FcPatternGetString(fontset->fonts[i], FC_STYLE, 0,
                           reinterpret_cast<FcChar8**>(&style)) !=
        FcResultMatch) {
      // Skip incomplete or malformed font.
      continue;
    }

    auto it_and_success = fonts_seen.emplace(postscript_name);
    if (!it_and_success.second) {
      // Skip duplicate.
      continue;
    }

    blink::FontEnumerationTable_FontData* data =
        font_enumeration_table.add_fonts();
    data->set_postscript_name(postscript_name);
    data->set_full_name(full_name);
    data->set_family(family);
    data->set_style(style);
  }

  return font_enumeration_table;
}

}  // namespace content