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Commit df7d3275 authored by Jooyung Han's avatar Jooyung Han
Browse files

fix: passing ResultError to Error thru operator<< 

It is typical to pass error to callers like following;

    if (!result) {
      return Error() << result.error();
    }

To transfer errno(or ResultError#code()), Error defines a specialization
operator<<(const ResultError&).

This change fixes so that ResultError is properly handled

Bug: 132145659
Test: atest libbase_test
Change-Id: Ib35457da2d4b923d8e652c54ac510a75546cf918
parent 5b63cff4

base/include/android-base/result.h

+5 −8
Original line number Diff line number Diff line
@@ -81,8 +81,7 @@ namespace base { 


struct ResultError {

  template <typename T>

  ResultError(T&& message, int code)

      : message_(std::forward<T>(message)), code_(code) {}

  ResultError(T&& message, int code) : message_(std::forward<T>(message)), code_(code) {}



  template <typename T>

  operator android::base::expected<T, ResultError>() {
@@ -122,18 +121,16 @@ class Error { 


  template <typename T>

  Error& operator<<(T&& t) {

    if constexpr (std::is_same_v<std::remove_cv_t<std::remove_reference_t<T>>, ResultError>) {

      errno_ = t.code();

      return (*this) << t.message();

    }

    int saved = errno;

    ss_ << t;

    errno = saved;

    return *this;

  }



  Error& operator<<(const ResultError& result_error) {

    (*this) << result_error.message();

    errno_ = result_error.code();

    return *this;

  }



  const std::string str() const {

    std::string str = ss_.str();

    if (append_errno_) {

base/result_test.cpp

+6 −6
Original line number Diff line number Diff line
@@ -143,8 +143,8 @@ TEST(result, result_error_from_other_result) { 
  ASSERT_FALSE(result2);

  ASSERT_FALSE(result2.has_value());



  EXPECT_EQ(0, result.error().code());

  EXPECT_EQ(error_text, result.error().message());

  EXPECT_EQ(0, result2.error().code());

  EXPECT_EQ(error_text, result2.error().message());

}



TEST(result, result_error_through_ostream) {
@@ -159,8 +159,8 @@ TEST(result, result_error_through_ostream) { 
  ASSERT_FALSE(result2);

  ASSERT_FALSE(result2.has_value());



  EXPECT_EQ(0, result.error().code());

  EXPECT_EQ(error_text, result.error().message());

  EXPECT_EQ(0, result2.error().code());

  EXPECT_EQ(error_text, result2.error().message());

}



TEST(result, result_errno_error_through_ostream) {
@@ -179,8 +179,8 @@ TEST(result, result_errno_error_through_ostream) { 
  ASSERT_FALSE(result2);

  ASSERT_FALSE(result2.has_value());



  EXPECT_EQ(test_errno, result.error().code());

  EXPECT_EQ(error_text + ": " + strerror(test_errno), result.error().message());

  EXPECT_EQ(test_errno, result2.error().code());

  EXPECT_EQ(error_text + ": " + strerror(test_errno), result2.error().message());

}



TEST(result, constructor_forwarding) {