Commit 2e497796 authored by Benjamin Kramer's avatar Benjamin Kramer
Browse files

[ADT] Implicitly convert between StringRef and std::string_view when we have C++17 

This makes the types almost seamlessly interchangeable in C++17
codebases. Eventually we want to replace StringRef with the standard
type, but that requires C++17 being the default and a huge refactoring
job as StringRef has a lot more functionality.
parent d8de3499

llvm/include/llvm/ADT/StringRef.h

+15 −0
Original line number Diff line number Diff line
@@ -18,6 +18,9 @@ 
#include <cstring>

#include <limits>

#include <string>

#if __cplusplus > 201402L

#include <string_view>

#endif

#include <type_traits>

#include <utility>
@@ -110,6 +113,12 @@ namespace llvm { 
    /*implicit*/ StringRef(const std::string &Str)

      : Data(Str.data()), Length(Str.length()) {}



#if __cplusplus > 201402L

    /// Construct a string ref from an std::string_view.

    /*implicit*/ constexpr StringRef(std::string_view Str)

        : Data(Str.data()), Length(Str.size()) {}

#endif



    static StringRef withNullAsEmpty(const char *data) {

      return StringRef(data ? data : "");

    }
@@ -267,6 +276,12 @@ namespace llvm { 
      return str();

    }



#if __cplusplus > 201402L

    operator std::string_view() const {

      return std::string_view(data(), size());

    }

#endif



    /// @}

    /// @name String Predicates

    /// @{

llvm/unittests/ADT/StringRefTest.cpp

+10 −0
Original line number Diff line number Diff line
@@ -59,6 +59,16 @@ TEST(StringRefTest, Construction) { 
  EXPECT_EQ("hello", StringRef("hello"));

  EXPECT_EQ("hello", StringRef("hello world", 5));

  EXPECT_EQ("hello", StringRef(std::string("hello")));

#if __cplusplus > 201402L

  EXPECT_EQ("hello", StringRef(std::string_view("hello")));

#endif

}



TEST(StringRefTest, Conversion) {

  EXPECT_EQ("hello", std::string(StringRef("hello")));

#if __cplusplus > 201402L

  EXPECT_EQ("hello", std::string_view(StringRef("hello")));

#endif

}



TEST(StringRefTest, EmptyInitializerList) {