icu_util.cc

Go to the documentation of this file.

// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#include "flutter/fml/icu_util.h"
 
#include <memory>
#include <mutex>
 
#include "flutter/fml/build_config.h"
#include "flutter/fml/logging.h"
#include "flutter/fml/mapping.h"
#include "flutter/fml/native_library.h"
#include "flutter/fml/paths.h"
#include "third_party/icu/source/common/unicode/udata.h"
 
namespace fml {
namespace icu {
 
class ICUContext {
 public:
  explicit ICUContext(const std::string& icu_data_path) : valid_(false) {
    valid_ = SetupMapping(icu_data_path) && SetupICU();
  }
 
  explicit ICUContext(std::unique_ptr<Mapping> mapping)
      : mapping_(std::move(mapping)) {
    valid_ = SetupICU();
  }
 
  ~ICUContext() = default;
 
  bool SetupMapping(const std::string& icu_data_path) {
    // Check if the path exists and it readable directly.
    auto fd =
        fml::OpenFile(icu_data_path.c_str(), false, fml::FilePermission::kRead);
 
    // Check the path relative to the current executable.
    if (!fd.is_valid()) {
      auto directory = fml::paths::GetExecutableDirectoryPath();
 
      if (!directory.first) {
        return false;
      }
 
      std::string path_relative_to_executable =
          paths::JoinPaths({directory.second, icu_data_path});
 
      fd = fml::OpenFile(path_relative_to_executable.c_str(), false,
                         fml::FilePermission::kRead);
    }
 
    if (!fd.is_valid()) {
      return false;
    }
 
    std::initializer_list<FileMapping::Protection> protection = {
        fml::FileMapping::Protection::kRead};
 
    auto file_mapping = std::make_unique<FileMapping>(fd, protection);
 
    if (file_mapping->GetSize() != 0) {
      mapping_ = std::move(file_mapping);
      return true;
    }
 
    return false;
  }
 
  bool SetupICU() {
    if (GetSize() == 0) {
      return false;
    }
 
    UErrorCode err_code = U_ZERO_ERROR;
    udata_setCommonData(GetMapping(), &err_code);
    return (err_code == U_ZERO_ERROR);
  }
 
  const uint8_t* GetMapping() const {
    return mapping_ ? mapping_->GetMapping() : nullptr;
  }
 
  size_t GetSize() const { return mapping_ ? mapping_->GetSize() : 0; }
 
  bool IsValid() const { return valid_; }
 
 private:
  bool valid_;
  std::unique_ptr<Mapping> mapping_;
 
  FML_DISALLOW_COPY_AND_ASSIGN(ICUContext);
};
 
void InitializeICUOnce(const std::string& icu_data_path) {
  static ICUContext* context = new ICUContext(icu_data_path);
  FML_CHECK(context->IsValid())
      << "Must be able to initialize the ICU context. Tried: " << icu_data_path;
}
 
std::once_flag g_icu_init_flag;
void InitializeICU(const std::string& icu_data_path) {
  std::call_once(g_icu_init_flag,
                 [&icu_data_path]() { InitializeICUOnce(icu_data_path); });
}
 
void InitializeICUFromMappingOnce(std::unique_ptr<Mapping> mapping) {
  static ICUContext* context = new ICUContext(std::move(mapping));
  FML_CHECK(context->IsValid())
      << "Unable to initialize the ICU context from a mapping.";
}
 
void InitializeICUFromMapping(std::unique_ptr<Mapping> mapping) {
  std::call_once(g_icu_init_flag, [mapping = std::move(mapping)]() mutable {
    InitializeICUFromMappingOnce(std::move(mapping));
  });
}
 
}  // namespace icu
}  // namespace fml