// Copyright 2014 The Chromium Authors. All rights reserved.

// Use of this source code is governed by a BSD-style license that can be

// found in the LICENSE file.

// This file contains macros and macro-like constructs (e.g., templates) that

// are commonly used throughout Chromium source. (It may also contain things

// that are closely related to things that are commonly used that belong in this

// file.)

#ifndef BUTIL_MACROS_H_

#define BUTIL_MACROS_H_

#include <stddef.h>  // For size_t.

#include <string.h>  // For memcpy.

#include <stdlib.h>

#include "butil/compiler_specific.h"  // For ALLOW_UNUSED.

#include "butil/string_printf.h"      // For butil::string_printf().

// There must be many copy-paste versions of these macros which are same

// things, undefine them to avoid conflict.

#undef DISALLOW_COPY

#undef DISALLOW_MOVE

#undef DISALLOW_ASSIGN

#undef DISALLOW_MOVE_ASSIGN

#undef DISALLOW_COPY_AND_ASSIGN

#undef DISALLOW_COPY_AND_MOVE

#undef DISALLOW_EVIL_CONSTRUCTORS

#undef DISALLOW_IMPLICIT_CONSTRUCTORS

#if !defined(BUTIL_CXX11_ENABLED)

#define BUTIL_DELETE_FUNCTION(decl) decl

#else

#define BUTIL_DELETE_FUNCTION(decl) decl = delete

#endif

// Declarations for a class to be uncopyable.

#define DISALLOW_COPY(TypeName)                         \

    BUTIL_DELETE_FUNCTION(TypeName(const TypeName&))

// Declarations for a class to be unmovable.

#define DISALLOW_MOVE(TypeName)                         \

    BUTIL_DELETE_FUNCTION(TypeName(TypeName&&))

// Declarations for a class to be unassignable.

#define DISALLOW_ASSIGN(TypeName)                        \

    BUTIL_DELETE_FUNCTION(TypeName& operator=(const TypeName&))

// Declarations for a class to be move-unassignable.

#define DISALLOW_MOVE_ASSIGN(TypeName)                   \

    BUTIL_DELETE_FUNCTION(TypeName& operator=(TypeName&&))

// A macro to disallow the copy constructor and operator= functions.

#define DISALLOW_COPY_AND_ASSIGN(TypeName)               \

    DISALLOW_COPY(TypeName);                             \

    DISALLOW_ASSIGN(TypeName)

// A macro to disallow the move constructor and operator= functions.

#define DISALLOW_MOVE_AND_ASSIGN(TypeName)               \

    DISALLOW_MOVE(TypeName);                             \

    DISALLOW_MOVE_ASSIGN(TypeName)

// A macro to disallow the copy constructor,

// the move constructor and operator= functions.

#define DISALLOW_COPY_AND_MOVE(TypeName)                 \

    DISALLOW_COPY_AND_ASSIGN(TypeName);                  \

    DISALLOW_MOVE(TypeName)

// An older, deprecated, politically incorrect name for the above.

// NOTE: The usage of this macro was banned from our code base, but some

// third_party libraries are yet using it.

// TODO(tfarina): Figure out how to fix the usage of this macro in the

// third_party libraries and get rid of it.

#define DISALLOW_EVIL_CONSTRUCTORS(TypeName) DISALLOW_COPY_AND_ASSIGN(TypeName)

// A macro to disallow all the implicit constructors, namely the

// default constructor, copy constructor and operator= functions.

//

// This should be used in the private: declarations for a class

// that wants to prevent anyone from instantiating it. This is

// especially useful for classes containing only static methods.

#define DISALLOW_IMPLICIT_CONSTRUCTORS(TypeName) \

    BUTIL_DELETE_FUNCTION(TypeName());            \

    DISALLOW_COPY_AND_ASSIGN(TypeName)

// Concatenate numbers in c/c++ macros.

#ifndef BAIDU_CONCAT

# define BAIDU_CONCAT(a, b) BAIDU_CONCAT_HELPER(a, b)

# define BAIDU_CONCAT_HELPER(a, b) a##b

#endif

#undef arraysize

// The arraysize(arr) macro returns the # of elements in an array arr.

// The expression is a compile-time constant, and therefore can be

// used in defining new arrays, for example.  If you use arraysize on

// a pointer by mistake, you will get a compile-time error.

//

// One caveat is that arraysize() doesn't accept any array of an

// anonymous type or a type defined inside a function.  In these rare

// cases, you have to use the unsafe ARRAYSIZE_UNSAFE() macro below.  This is

// due to a limitation in C++'s template system.  The limitation might

// eventually be removed, but it hasn't happened yet.

// This template function declaration is used in defining arraysize.

// Note that the function doesn't need an implementation, as we only

// use its type.    

namespace butil {

template <typename T, size_t N>

char (&ArraySizeHelper(T (&array)[N]))[N];

}

// That gcc wants both of these prototypes seems mysterious. VC, for

// its part, can't decide which to use (another mystery). Matching of

// template overloads: the final frontier.

#ifndef _MSC_VER

namespace butil {

template <typename T, size_t N>

char (&ArraySizeHelper(const T (&array)[N]))[N];

}

#endif

#define arraysize(array) (sizeof(::butil::ArraySizeHelper(array)))

// gejun: Following macro was used in other modules.

#undef ARRAY_SIZE

#define ARRAY_SIZE(array) arraysize(array)

// ARRAYSIZE_UNSAFE performs essentially the same calculation as arraysize,

// but can be used on anonymous types or types defined inside

// functions.  It's less safe than arraysize as it accepts some

// (although not all) pointers.  Therefore, you should use arraysize

// whenever possible.

//

// The expression ARRAYSIZE_UNSAFE(a) is a compile-time constant of type

// size_t.

//

// ARRAYSIZE_UNSAFE catches a few type errors.  If you see a compiler error

//

//   "warning: division by zero in ..."

//

// when using ARRAYSIZE_UNSAFE, you are (wrongfully) giving it a pointer.

// You should only use ARRAYSIZE_UNSAFE on statically allocated arrays.

//

// The following comments are on the implementation details, and can

// be ignored by the users.

//

// ARRAYSIZE_UNSAFE(arr) works by inspecting sizeof(arr) (the # of bytes in

// the array) and sizeof(*(arr)) (the # of bytes in one array

// element).  If the former is divisible by the latter, perhaps arr is

// indeed an array, in which case the division result is the # of

// elements in the array.  Otherwise, arr cannot possibly be an array,

// and we generate a compiler error to prevent the code from

// compiling.

//

// Since the size of bool is implementation-defined, we need to cast

// !(sizeof(a) & sizeof(*(a))) to size_t in order to ensure the final

// result has type size_t.

//

// This macro is not perfect as it wrongfully accepts certain

// pointers, namely where the pointer size is divisible by the pointee

// size.  Since all our code has to go through a 32-bit compiler,

// where a pointer is 4 bytes, this means all pointers to a type whose

// size is 3 or greater than 4 will be (righteously) rejected.

#undef ARRAYSIZE_UNSAFE

#define ARRAYSIZE_UNSAFE(a) \

    ((sizeof(a) / sizeof(*(a))) / \

     static_cast<size_t>(!(sizeof(a) % sizeof(*(a)))))

// Use implicit_cast as a safe version of static_cast or const_cast

// for upcasting in the type hierarchy (i.e. casting a pointer to Foo

// to a pointer to SuperclassOfFoo or casting a pointer to Foo to

// a const pointer to Foo).

// When you use implicit_cast, the compiler checks that the cast is safe.

// Such explicit implicit_casts are necessary in surprisingly many

// situations where C++ demands an exact type match instead of an

// argument type convertible to a target type.

//

// The From type can be inferred, so the preferred syntax for using

// implicit_cast is the same as for static_cast etc.:

//

//   implicit_cast<ToType>(expr)

//

// implicit_cast would have been part of the C++ standard library,

// but the proposal was submitted too late.  It will probably make

// its way into the language in the future.

namespace butil {

template<typename To, typename From>

inline To implicit_cast(From const &f) {

  return f;

}

}

#if defined(BUTIL_CXX11_ENABLED)

// C++11 supports compile-time assertion directly

#define BAIDU_CASSERT(expr, msg) static_assert(expr, #msg)

#else

// Assert constant boolean expressions at compile-time

// Params:

//   expr     the constant expression to be checked

//   msg      an error infomation conforming name conventions of C/C++

//            variables(alphabets/numbers/underscores, no blanks). For

//            example "cannot_accept_a_number_bigger_than_128" is valid

//            while "this number is out-of-range" is illegal.

//

// when an asssertion like "BAIDU_CASSERT(false, you_should_not_be_here)"

// breaks, a compilation error is printed:

//   

//   foo.cpp:401: error: enumerator value for `you_should_not_be_here___19' not

//   integer constant

//

// You can call BAIDU_CASSERT at global scope, inside a class or a function

// 

//   BAIDU_CASSERT(false, you_should_not_be_here);

//   int main () { ... }

//

//   struct Foo {

//       BAIDU_CASSERT(1 == 0, Never_equals);

//   };

//

//   int bar(...)

//   {

//       BAIDU_CASSERT (value < 10, invalid_value);

//   }

//

namespace butil {

template <bool> struct CAssert { static const int x = 1; };

template <> struct CAssert<false> { static const char * x; };

}

#define BAIDU_CASSERT(expr, msg)                                \

    enum { BAIDU_CONCAT(BAIDU_CONCAT(LINE_, __LINE__), __##msg) \

           = ::butil::CAssert<!!(expr)>::x };

#endif  // BUTIL_CXX11_ENABLED

// The impl. of chrome does not work for offsetof(Object, private_filed)

#undef COMPILE_ASSERT

#define COMPILE_ASSERT(expr, msg)  BAIDU_CASSERT(expr, msg)

// bit_cast<Dest,Source> is a template function that implements the

// equivalent of "*reinterpret_cast<Dest*>(&source)".  We need this in

// very low-level functions like the protobuf library and fast math

// support.

//

//   float f = 3.14159265358979;

//   int i = bit_cast<int32_t>(f);

//   // i = 0x40490fdb

//

// The classical address-casting method is:

//

//   // WRONG

//   float f = 3.14159265358979;            // WRONG

//   int i = * reinterpret_cast<int*>(&f);  // WRONG

//

// The address-casting method actually produces undefined behavior

// according to ISO C++ specification section 3.10 -15 -.  Roughly, this

// section says: if an object in memory has one type, and a program

// accesses it with a different type, then the result is undefined

// behavior for most values of "different type".

//

// This is true for any cast syntax, either *(int*)&f or

// *reinterpret_cast<int*>(&f).  And it is particularly true for

// conversions between integral lvalues and floating-point lvalues.

//

// The purpose of 3.10 -15- is to allow optimizing compilers to assume

// that expressions with different types refer to different memory.  gcc

// 4.0.1 has an optimizer that takes advantage of this.  So a

// non-conforming program quietly produces wildly incorrect output.

//

// The problem is not the use of reinterpret_cast.  The problem is type

// punning: holding an object in memory of one type and reading its bits

// back using a different type.

//

// The C++ standard is more subtle and complex than this, but that

// is the basic idea.

//

// Anyways ...

//

// bit_cast<> calls memcpy() which is blessed by the standard,

// especially by the example in section 3.9 .  Also, of course,

// bit_cast<> wraps up the nasty logic in one place.

//

// Fortunately memcpy() is very fast.  In optimized mode, with a

// constant size, gcc 2.95.3, gcc 4.0.1, and msvc 7.1 produce inline

// code with the minimal amount of data movement.  On a 32-bit system,

// memcpy(d,s,4) compiles to one load and one store, and memcpy(d,s,8)

// compiles to two loads and two stores.

//

// I tested this code with gcc 2.95.3, gcc 4.0.1, icc 8.1, and msvc 7.1.

//

// WARNING: if Dest or Source is a non-POD type, the result of the memcpy

// is likely to surprise you.

namespace butil {

template <class Dest, class Source>

inline Dest bit_cast(const Source& source) {

  COMPILE_ASSERT(sizeof(Dest) == sizeof(Source), VerifySizesAreEqual);

  Dest dest;

  memcpy(&dest, &source, sizeof(dest));

  return dest;

}

}  // namespace butil

// Used to explicitly mark the return value of a function as unused. If you are

// really sure you don't want to do anything with the return value of a function

// that has been marked WARN_UNUSED_RESULT, wrap it with this. Example:

//

//   scoped_ptr<MyType> my_var = ...;

//   if (TakeOwnership(my_var.get()) == SUCCESS)

//     ignore_result(my_var.release());

//

namespace butil {

template<typename T>

inline void ignore_result(const T&) {

}

Unexecuted instantiation: void butil::ignore_result<long>(long const&)

Unexecuted instantiation: void butil::ignore_result<int>(int const&)

} // namespace butil

// The following enum should be used only as a constructor argument to indicate

// that the variable has static storage class, and that the constructor should

// do nothing to its state.  It indicates to the reader that it is legal to

// declare a static instance of the class, provided the constructor is given

// the butil::LINKER_INITIALIZED argument.  Normally, it is unsafe to declare a

// static variable that has a constructor or a destructor because invocation

// order is undefined.  However, IF the type can be initialized by filling with

// zeroes (which the loader does for static variables), AND the destructor also

// does nothing to the storage, AND there are no virtual methods, then a

// constructor declared as

//       explicit MyClass(butil::LinkerInitialized x) {}

// and invoked as

//       static MyClass my_variable_name(butil::LINKER_INITIALIZED);

namespace butil {

enum LinkerInitialized { LINKER_INITIALIZED };

// Use these to declare and define a static local variable (static T;) so that

// it is leaked so that its destructors are not called at exit. If you need

// thread-safe initialization, use butil/lazy_instance.h instead.

#undef CR_DEFINE_STATIC_LOCAL

#define CR_DEFINE_STATIC_LOCAL(type, name, arguments) \

  static type& name = *new type arguments

}  // namespace butil

// Convert symbol to string

#ifndef BAIDU_SYMBOLSTR

# define BAIDU_SYMBOLSTR(a) BAIDU_SYMBOLSTR_HELPER(a)

# define BAIDU_SYMBOLSTR_HELPER(a) #a

#endif

#ifndef BAIDU_TYPEOF

# if defined(BUTIL_CXX11_ENABLED)

#  define BAIDU_TYPEOF decltype

# else

#  ifdef _MSC_VER

#   include <boost/typeof/typeof.hpp>

#   define BAIDU_TYPEOF BOOST_TYPEOF

#  else

#   define BAIDU_TYPEOF typeof

#  endif

# endif // BUTIL_CXX11_ENABLED

#endif  // BAIDU_TYPEOF

// ptr:     the pointer to the member.

// type:    the type of the container struct this is embedded in.

// member:  the name of the member within the struct.

#ifndef container_of

# define container_of(ptr, type, member) ({                             \

            const BAIDU_TYPEOF( ((type *)0)->member ) *__mptr = (ptr);  \

            (type *)( (char *)__mptr - offsetof(type,member) );})

#endif

// DEFINE_SMALL_ARRAY(MyType, my_array, size, 64);

//   my_array is typed `MyType*' and as long as `size'. If `size' is not

//   greater than 64, the array is allocated on stack.

//

// NOTE: NEVER use ARRAY_SIZE(my_array) which is always 1.

#if defined(__cplusplus)

namespace butil {

namespace internal {

template <typename T> struct ArrayDeleter {

    ArrayDeleter() : arr(0) {}

    ~ArrayDeleter() { delete[] arr; }

    T* arr;

};

}}

// Many versions of clang does not support variable-length array with non-pod

// types, have to implement the macro differently.

#if !defined(__clang__)

# define DEFINE_SMALL_ARRAY(Tp, name, size, maxsize)                    \

    Tp* name = 0;                                                       \

    const unsigned name##_size = (size);                                \

    const unsigned name##_stack_array_size = (name##_size <= (maxsize) ? name##_size : 0); \

    Tp name##_stack_array[name##_stack_array_size];                     \

    ::butil::internal::ArrayDeleter<Tp> name##_array_deleter;            \

    if (name##_stack_array_size) {                                      \

        name = name##_stack_array;                                      \

    } else {                                                            \

        name = new (::std::nothrow) Tp[name##_size];                    \

        name##_array_deleter.arr = name;                                \

    }

#else

// This implementation works for GCC as well, however it needs extra 16 bytes

// for ArrayCtorDtor.

namespace butil {

namespace internal {

template <typename T> struct ArrayCtorDtor {

    ArrayCtorDtor(void* arr, unsigned size) : _arr((T*)arr), _size(size) {

        for (unsigned i = 0; i < size; ++i) { new (_arr + i) T; }

    }

Unexecuted instantiation: butil::internal::ArrayCtorDtor<unsigned int>::ArrayCtorDtor(void*, unsigned int)

Unexecuted instantiation: butil::internal::ArrayCtorDtor<int>::ArrayCtorDtor(void*, unsigned int)

Unexecuted instantiation: butil::internal::ArrayCtorDtor<butil::IOBuf*>::ArrayCtorDtor(void*, unsigned int)

Unexecuted instantiation: butil::internal::ArrayCtorDtor<brpc::SubCall>::ArrayCtorDtor(void*, unsigned int)

Unexecuted instantiation: butil::internal::ArrayCtorDtor<char>::ArrayCtorDtor(void*, unsigned int)

    ~ArrayCtorDtor() {

        for (unsigned i = 0; i < _size; ++i) { _arr[i].~T(); }

    }

Unexecuted instantiation: butil::internal::ArrayCtorDtor<unsigned int>::~ArrayCtorDtor()

Unexecuted instantiation: butil::internal::ArrayCtorDtor<int>::~ArrayCtorDtor()

Unexecuted instantiation: butil::internal::ArrayCtorDtor<butil::IOBuf*>::~ArrayCtorDtor()

Unexecuted instantiation: butil::internal::ArrayCtorDtor<brpc::SubCall>::~ArrayCtorDtor()

Unexecuted instantiation: butil::internal::ArrayCtorDtor<char>::~ArrayCtorDtor()

private:

    T* _arr;

    unsigned _size;

};

}}

# define DEFINE_SMALL_ARRAY(Tp, name, size, maxsize)                    \

    Tp* name = 0;                                                       \

    const unsigned name##_size = (size);                                \

    const unsigned name##_stack_array_size = (name##_size <= (maxsize) ? name##_size : 0); \

    char name##_stack_array[sizeof(Tp) * name##_stack_array_size];      \

    ::butil::internal::ArrayDeleter<char> name##_array_deleter;          \

    if (name##_stack_array_size) {                                      \

        name = (Tp*)name##_stack_array;                                 \

    } else {                                                            \

        name = (Tp*)new (::std::nothrow) char[sizeof(Tp) * name##_size];\

        name##_array_deleter.arr = (char*)name;                         \

    }                                                                   \

    const ::butil::internal::ArrayCtorDtor<Tp> name##_array_ctor_dtor(name, name##_size);

#endif // !defined(__clang__)

#endif // defined(__cplusplus)

// Put following code somewhere global to run it before main():

// 

//   BAIDU_GLOBAL_INIT()

//   {

//       ... your code ...

//   }

//

// Your can:

//   * Write any code and access global variables.

//   * Use ASSERT_*.

//   * Have multiple BAIDU_GLOBAL_INIT() in one scope.

// 

// Since the code run in global scope, quit with exit() or similar functions.

#if defined(__cplusplus)

# define BAIDU_GLOBAL_INIT                                      \

namespace {  /*anonymous namespace */                           \

    struct BAIDU_CONCAT(BaiduGlobalInit, __LINE__) {            \

        BAIDU_CONCAT(BaiduGlobalInit, __LINE__)() { init(); }   \

        void init();                                            \

    } BAIDU_CONCAT(baidu_global_init_dummy_, __LINE__);         \

}  /* anonymous namespace */                                    \

    void BAIDU_CONCAT(BaiduGlobalInit, __LINE__)::init              

#else

# define BAIDU_GLOBAL_INIT                      \

    static void __attribute__((constructor))    \

    BAIDU_CONCAT(baidu_global_init_, __LINE__)

#endif  // __cplusplus

#define ASSERT_LOG(fmt, ...)                                            \

    do {                                                                \

        std::string log = butil::string_printf(fmt, ## __VA_ARGS__);    \

        LOG(FATAL) << log;                                              \

    } while (false)

// Assert macro that can crash the process to generate a dump.

#define RELEASE_ASSERT(condition)   \

    do {                            \

        if (!(condition)) {         \

            ::abort();              \

        }                           \

    } while (false)

// Assert macro that can crash the process to generate a dump and

// supply a verbose explanation of what went wrong.

// For example:

//  std::vector<int> v;

//  ...

//  RELEASE_ASSERT_VERBOSE(v.empty(), "v should be empty, but with size=%zu", v.size());

#define RELEASE_ASSERT_VERBOSE(condition, fmt, ...)                                 \

    do {                                                                            \

        if (!(condition)) {                                                         \

            ASSERT_LOG("Assert failure: " #condition ". " #fmt, ## __VA_ARGS__);    \

            ::abort();                                                              \

        }                                                                           \

    } while (false)

#endif  // BUTIL_MACROS_H_