Move mojo edk into mojo/edk

mojo/system/options_validation.h

-// 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.
-
-// Functions to help with verifying various |Mojo...Options| structs from the
-// (public, C) API. These are "extensible" structs, which all have |struct_size|
-// as their first member. All fields (other than |struct_size|) are optional,
-// but any |flags| specified must be known to the system (otherwise, an error of
-// |MOJO_RESULT_UNIMPLEMENTED| should be returned).
-
-#ifndef MOJO_SYSTEM_OPTIONS_VALIDATION_H_
-#define MOJO_SYSTEM_OPTIONS_VALIDATION_H_
-
-#include <stddef.h>
-#include <stdint.h>
-
-#include <algorithm>
-
-#include "base/logging.h"
-#include "base/macros.h"
-#include "mojo/public/c/system/types.h"
-#include "mojo/system/constants.h"
-#include "mojo/system/memory.h"
-#include "mojo/system/system_impl_export.h"
-
-namespace mojo {
-namespace system {
-
-template <class Options>
-class UserOptionsReader {
- public:
-  // Constructor from a |UserPointer<const Options>| (which it checks -- this
-  // constructor has side effects!).
-  // Note: We initialize |options_reader_| without checking, since we do a check
-  // in |GetSizeForReader()|.
-  explicit UserOptionsReader(UserPointer<const Options> options)
-      : options_reader_(UserPointer<const char>::Reader::NoCheck(),
-                        options.template ReinterpretCast<const char>(),
-                        GetSizeForReader(options)) {
-    static_assert(offsetof(Options, struct_size) == 0,
-                  "struct_size not first member of Options");
-    // TODO(vtl): Enable when MSVC supports this (C++11 extended sizeof):
-    //   static_assert(sizeof(Options::struct_size) == sizeof(uint32_t),
-    //                 "Options::struct_size not a uint32_t");
-    // (Or maybe assert that its type is uint32_t?)
-  }
-
-  bool is_valid() const { return !!options_reader_.GetPointer(); }
-
-  const Options& options() const {
-    DCHECK(is_valid());
-    return *reinterpret_cast<const Options*>(options_reader_.GetPointer());
-  }
-
-  // Checks that the given (variable-size) |options| passed to the constructor
-  // (plausibly) has a member at the given offset with the given size. You
-  // probably want to use |OPTIONS_STRUCT_HAS_MEMBER()| instead.
-  bool HasMember(size_t offset, size_t size) const {
-    DCHECK(is_valid());
-    // We assume that |offset| and |size| are reasonable, since they should come
-    // from |offsetof(Options, some_member)| and |sizeof(Options::some_member)|,
-    // respectively.
-    return options().struct_size >= offset + size;
-  }
-
- private:
-  static inline size_t GetSizeForReader(UserPointer<const Options> options) {
-    uint32_t struct_size =
-        options.template ReinterpretCast<const uint32_t>().Get();
-    if (struct_size < sizeof(uint32_t))
-      return 0;
-
-    // Check the full requested size.
-    // Note: Use |MOJO_ALIGNOF()| here to match the exact macro used in the
-    // declaration of Options structs.
-    internal::CheckUserPointerWithSize<MOJO_ALIGNOF(Options)>(options.pointer_,
-                                                              struct_size);
-    options.template ReinterpretCast<const char>().CheckArray(struct_size);
-    // But we'll never look at more than |sizeof(Options)| bytes.
-    return std::min(static_cast<size_t>(struct_size), sizeof(Options));
-  }
-
-  UserPointer<const char>::Reader options_reader_;
-
-  DISALLOW_COPY_AND_ASSIGN(UserOptionsReader);
-};
-
-// Macro to invoke |UserOptionsReader<Options>::HasMember()| parametrized by
-// member name instead of offset and size.
-//
-// (We can't just give |HasMember()| a member pointer template argument instead,
-// since there's no good/strictly-correct way to get an offset from that.)
-//
-// TODO(vtl): With C++11, use |sizeof(Options::member)| instead of (the
-// contortion below). We might also be able to pull out the type |Options| from
-// |reader| (using |decltype|) instead of requiring a parameter.
-#define OPTIONS_STRUCT_HAS_MEMBER(Options, member, reader) \
-  reader.HasMember(offsetof(Options, member), sizeof(reader.options().member))
-
-}  // namespace system
-}  // namespace mojo
-
-#endif  // MOJO_SYSTEM_OPTIONS_VALIDATION_H_