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(2011)

Unified Diff: base/macros.h

Issue 1647803004: Move base to DEPS (Closed) Base URL: git@github.com:domokit/mojo.git@master
Patch Set: Created 4 years, 11 months ago
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Index: base/macros.h
diff --git a/base/macros.h b/base/macros.h
deleted file mode 100644
index 53b3926cd2424ac355304f1110e0150696aec4ce..0000000000000000000000000000000000000000
--- a/base/macros.h
+++ /dev/null
@@ -1,198 +0,0 @@
-// 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 BASE_MACROS_H_
-#define BASE_MACROS_H_
-
-#include <stddef.h> // For size_t.
-#include <string.h> // For memcpy.
-
-// Put this in the declarations for a class to be uncopyable.
-#define DISALLOW_COPY(TypeName) \
- TypeName(const TypeName&) = delete
-
-// Put this in the declarations for a class to be unassignable.
-#define DISALLOW_ASSIGN(TypeName) \
- void operator=(const TypeName&) = delete
-
-// A macro to disallow the copy constructor and operator= functions
-// This should be used in the private: declarations for a class
-#define DISALLOW_COPY_AND_ASSIGN(TypeName) \
- TypeName(const TypeName&); \
- void operator=(const 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) \
- TypeName() = delete; \
- DISALLOW_COPY_AND_ASSIGN(TypeName)
-
-// 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.
-
-// This template function declaration is used in defining arraysize.
-// Note that the function doesn't need an implementation, as we only
-// use its type.
-template <typename T, size_t N> char (&ArraySizeHelper(T (&array)[N]))[N];
-#define arraysize(array) (sizeof(ArraySizeHelper(array)))
-
-
-// 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.
-template<typename To, typename From>
-inline To implicit_cast(From const &f) {
- return f;
-}
-
-// The COMPILE_ASSERT macro can be used to verify that a compile time
-// expression is true. For example, you could use it to verify the
-// size of a static array:
-//
-// COMPILE_ASSERT(arraysize(content_type_names) == CONTENT_NUM_TYPES,
-// content_type_names_incorrect_size);
-//
-// or to make sure a struct is smaller than a certain size:
-//
-// COMPILE_ASSERT(sizeof(foo) < 128, foo_too_large);
-//
-// The second argument to the macro is the name of the variable. If
-// the expression is false, most compilers will issue a warning/error
-// containing the name of the variable.
-
-#undef COMPILE_ASSERT
-#define COMPILE_ASSERT(expr, msg) static_assert(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>(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.
-
-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;
-}
-
-// 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());
-//
-template<typename T>
-inline void ignore_result(const T&) {
-}
-
-// 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 base::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(base::LinkerInitialized x) {}
-// and invoked as
-// static MyClass my_variable_name(base::LINKER_INITIALIZED);
-namespace base {
-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 base/lazy_instance.h instead.
-#define CR_DEFINE_STATIC_LOCAL(type, name, arguments) \
- static type& name = *new type arguments
-
-} // base
-
-#endif // BASE_MACROS_H_
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