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// Author: wan@google.com (Zhanyong Wan)
//
// The Google C++ Testing Framework (Google Test)
//
// This header file defines the Message class.
//
// IMPORTANT NOTE: Due to limitation of the C++ language, we have to
// leave some internal implementation details in this header file.
// They are clearly marked by comments like this:
//
// // INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
//
// Such code is NOT meant to be used by a user directly, and is subject
// to CHANGE WITHOUT NOTICE. Therefore DO NOT DEPEND ON IT in a user
// program!
#ifndef GTEST_INCLUDE_GTEST_GTEST_MESSAGE_H_
#define GTEST_INCLUDE_GTEST_GTEST_MESSAGE_H_
#include <limits>
#include "gtest/internal/gtest-port.h"
// Ensures that there is at least one operator<< in the global namespace.
// See Message& operator<<(...) below for why.
void operator<<(const testing::internal::Secret&, int);
namespace testing {
// The Message class works like an ostream repeater.
//
// Typical usage:
//
// 1. You stream a bunch of values to a Message object.
// It will remember the text in a stringstream.
// 2. Then you stream the Message object to an ostream.
// This causes the text in the Message to be streamed
// to the ostream.
//
// For example;
//
// testing::Message foo;
// foo << 1 << " != " << 2;
// std::cout << foo;
//
// will print "1 != 2".
//
// Message is not intended to be inherited from. In particular, its
// destructor is not virtual.
//
// Note that stringstream behaves differently in gcc and in MSVC. You
// can stream a NULL char pointer to it in the former, but not in the
// latter (it causes an access violation if you do). The Message
// class hides this difference by treating a NULL char pointer as
// "(null)".
class GTEST_API_ Message {
private:
// The type of basic IO manipulators (endl, ends, and flush) for
// narrow streams.
typedef std::ostream& (*BasicNarrowIoManip)(std::ostream&);
public:
// Constructs an empty Message.
Message();
// Copy constructor.
Message(const Message& msg) : ss_(new ::std::stringstream) { // NOLINT
*ss_ << msg.GetString();
}
// Constructs a Message from a C-string.
explicit Message(const char* str) : ss_(new ::std::stringstream) {
*ss_ << str;
}
#if GTEST_OS_SYMBIAN
// Streams a value (either a pointer or not) to this object.
template <typename T>
inline Message& operator <<(const T& value) {
StreamHelper(typename internal::is_pointer<T>::type(), value);
return *this;
}
#else
// Streams a non-pointer value to this object.
template <typename T>
inline Message& operator <<(const T& val) {
// Some libraries overload << for STL containers. These
// overloads are defined in the global namespace instead of ::std.
//
// C++'s symbol lookup rule (i.e. Koenig lookup) says that these
// overloads are visible in either the std namespace or the global
// namespace, but not other namespaces, including the testing
// namespace which Google Test's Message class is in.
//
// To allow STL containers (and other types that has a << operator
// defined in the global namespace) to be used in Google Test
// assertions, testing::Message must access the custom << operator
// from the global namespace. With this using declaration,
// overloads of << defined in the global namespace and those
// visible via Koenig lookup are both exposed in this function.
using ::operator <<;
*ss_ << val;
return *this;
}
// Streams a pointer value to this object.
//
// This function is an overload of the previous one. When you
// stream a pointer to a Message, this definition will be used as it
// is more specialized. (The C++ Standard, section
// [temp.func.order].) If you stream a non-pointer, then the
// previous definition will be used.
//
// The reason for this overload is that streaming a NULL pointer to
// ostream is undefined behavior. Depending on the compiler, you
// may get "0", "(nil)", "(null)", or an access violation. To
// ensure consistent result across compilers, we always treat NULL
// as "(null)".
template <typename T>
inline Message& operator <<(T* const& pointer) { // NOLINT
if (pointer == NULL) {
*ss_ << "(null)";
} else {
*ss_ << pointer;
}
return *this;
}
#endif // GTEST_OS_SYMBIAN
// Since the basic IO manipulators are overloaded for both narrow
// and wide streams, we have to provide this specialized definition
// of operator <<, even though its body is the same as the
// templatized version above. Without this definition, streaming
// endl or other basic IO manipulators to Message will confuse the
// compiler.
Message& operator <<(BasicNarrowIoManip val) {
*ss_ << val;
return *this;
}
// Instead of 1/0, we want to see true/false for bool values.
Message& operator <<(bool b) {
return *this << (b ? "true" : "false");
}
// These two overloads allow streaming a wide C string to a Message
// using the UTF-8 encoding.
Message& operator <<(const wchar_t* wide_c_str);
Message& operator <<(wchar_t* wide_c_str);
#if GTEST_HAS_STD_WSTRING
// Converts the given wide string to a narrow string using the UTF-8
// encoding, and streams the result to this Message object.
Message& operator <<(const ::std::wstring& wstr);
#endif // GTEST_HAS_STD_WSTRING
#if GTEST_HAS_GLOBAL_WSTRING
// Converts the given wide string to a narrow string using the UTF-8
// encoding, and streams the result to this Message object.
Message& operator <<(const ::wstring& wstr);
#endif // GTEST_HAS_GLOBAL_WSTRING
// Gets the text streamed to this object so far as an std::string.
// Each '\0' character in the buffer is replaced with "\\0".
//
// INTERNAL IMPLEMENTATION - DO NOT USE IN A USER PROGRAM.
std::string GetString() const;
private:
#if GTEST_OS_SYMBIAN
// These are needed as the Nokia Symbian Compiler cannot decide between
// const T& and const T* in a function template. The Nokia compiler _can_
// decide between class template specializations for T and T*, so a
// tr1::type_traits-like is_pointer works, and we can overload on that.
template <typename T>
inline void StreamHelper(internal::true_type /*is_pointer*/, T* pointer) {
if (pointer == NULL) {
*ss_ << "(null)";
} else {
*ss_ << pointer;
}
}
template <typename T>
inline void StreamHelper(internal::false_type /*is_pointer*/,
const T& value) {
// See the comments in Message& operator <<(const T&) above for why
// we need this using statement.
using ::operator <<;
*ss_ << value;
}
#endif // GTEST_OS_SYMBIAN
// We'll hold the text streamed to this object here.
const internal::scoped_ptr< ::std::stringstream> ss_;
// We declare (but don't implement) this to prevent the compiler
// from implementing the assignment operator.
void operator=(const Message&);
};
// Streams a Message to an ostream.
inline std::ostream& operator <<(std::ostream& os, const Message& sb) {
return os << sb.GetString();
}
namespace internal {
// Converts a streamable value to an std::string. A NULL pointer is
// converted to "(null)". When the input value is a ::string,
// ::std::string, ::wstring, or ::std::wstring object, each NUL
// character in it is replaced with "\\0".
template <typename T>
std::string StreamableToString(const T& streamable) {
return (Message() << streamable).GetString();
}
} // namespace internal
} // namespace testing
#endif // GTEST_INCLUDE_GTEST_GTEST_MESSAGE_H_