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#include "base/environ.h"

#include <cstdlib>
#include <string>

#include "base/singleton.h"
#include "base/strings/zstring_view.h"

namespace mozc {

namespace {
class EnvironImpl : public EnvironInterface {
 public:
  EnvironImpl() = default;
  ~EnvironImpl() override = default;

  std::string GetEnv(zstring_view env_var) override {
    const char* value = std::getenv(env_var.data());
    return value == nullptr ? "" : value;
  }
};

using EnvironSingleton = SingletonMockable<EnvironInterface, EnvironImpl>;
}  // namespace

std::string Environ::GetEnv(zstring_view env_var) {
  return EnvironSingleton::Get()->GetEnv(env_var.data());
}

void Environ::SetMockForUnitTest(EnvironInterface* mock) {
  EnvironSingleton::SetMock(mock);
}

}  // namespace mozc
