Make the fuchsia mojo/public repo the source of truth.

mojo/public/c/include/mojo/bindings/union.h

-// Copyright 2016 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.
-
-#ifndef MOJO_PUBLIC_C_INCLUDE_MOJO_BINDINGS_UNION_H_
-#define MOJO_PUBLIC_C_INCLUDE_MOJO_BINDINGS_UNION_H_
-
-#include <mojo/bindings/buffer.h>
-#include <mojo/bindings/internal/type_descriptor.h>
-#include <mojo/bindings/internal/util.h>
-#include <mojo/macros.h>
-#include <stddef.h>
-#include <stdint.h>
-
-MOJO_BEGIN_EXTERN_C
-
-struct MojomUnionLayout {
-  // |num_bytes|, the number of bytes used in this union, includes the size of
-  // the |num_bytes| and |tag| fields, along with data.
-  uint32_t size;
-  uint32_t tag;
-  union {
-    // To be used when the data is a pointer.
-    union MojomPointer pointer;
-
-    // This is here to force this union data to be at least 8 bytes.
-    uint64_t force_size_;
-  } data;
-};
-MOJO_STATIC_ASSERT(sizeof(struct MojomUnionLayout) == 16,
-                   "struct MojomUnionLayout must be 16 bytes.");
-
-// Returns the number of bytes required to serialize |in_union_data|'s active
-// field, not including the union layout (as described by |struct
-// MojomUnionLayout|) itself.
-// |in_type_desc| is the generated type that describes the tags of the pointer
-// and handle types in the given union.
-size_t MojomUnion_ComputeSerializedSize(
-    const struct MojomTypeDescriptorUnion* in_type_desc,
-    const struct MojomUnionLayout* in_union_data);
-
-// Encodes the mojom union described by the |inout_union| buffer; note that any
-// references from the union are also in the buffer backed by |inout_union|, and
-// they are recursively encoded. Encodes all pointers to relative offsets, and
-// encodes all handles by moving them into |inout_handles_buffer| and encoding
-// the index into the handle.
-// |in_type_desc|: Describes the pointer and handle fields of the mojom union.
-// |inout_union|: Contains the union, and any other references outside the
-//                union.
-// |in_union_size|: Size of the buffer backed by |inout_union| in bytes.
-// |inout_handles_buffer|:
-//   A buffer used to record handles during encoding. The |num_handles_used|
-//   field can be used to determine how many handles were moved into this
-//   buffer.
-void MojomUnion_EncodePointersAndHandles(
-    const struct MojomTypeDescriptorUnion* in_type_desc,
-    struct MojomUnionLayout* inout_union,
-    uint32_t in_union_size,
-    struct MojomHandleBuffer* inout_handles_buffer);
-
-// Decodes the mojom union described by the |inout_union| buffer; note that any
-// references from the union are also in the buffer backed by |inout_union|, and
-// they are recursively decoded. Decodes all offsets to pointers, and decodes
-// all handles by moving them out of |inout_handles| using the encoded index.
-// |in_type_desc|: Describes the pointer and handle fields of the mojom union.
-// |inout_union|: Contains the union, and any other references outside the
-//                union.
-// |in_union_size|: Size of the buffer backed by |inout_union| in bytes.
-// |inout_handles|: Mojo handles are moved out of this array and into
-//                  |inout_union|, using the encoded index into this array.
-// |in_num_handles|: Size in # of number elements available in |inout_handles|.
-void MojomUnion_DecodePointersAndHandles(
-    const struct MojomTypeDescriptorUnion* in_type_desc,
-    struct MojomUnionLayout* inout_union,
-    uint32_t in_union_size,
-    MojoHandle* inout_handles,
-    uint32_t in_num_handles);
-
-// Validates the mojom union described by the |in_union| buffer. Any
-// references from the union are also recursively validated, and are expected to
-// be in the same buffer backing |in_union|.
-// |in_type_desc|: Describes the pointer and handle fields of the mojom union.
-// |in_union|: Buffer containing the union, and any other references
-//             outside of the union.
-// |in_union_size|: Size of the buffer backed by |in_union| in bytes.
-// |in_num_handles|: Number of valid handles expected to be referenced from
-//                   |in_union|.
-// |inout_context|: An initialized context that contains the expected location
-//                  of the next pointer and next offset. This is used to
-//                  validate that no two pointers or handles are shared.
-MojomValidationResult MojomUnion_Validate(
-    const struct MojomTypeDescriptorUnion* in_type_desc,
-    bool in_nullable,
-    const struct MojomUnionLayout* in_union,
-    uint32_t in_union_size,
-    uint32_t in_num_handles,
-    struct MojomValidationContext* inout_context);
-
-// Copies over |in_union_data| into |out_union_data|, recursively copying any
-// references from |in_union_data| using |buffer| to allocate space, and
-// updating the references to point to the new copies. Note that a space is
-// never allocated for the new union data in this function -- |out_union_data|
-// should already be allocated for this function ahead of time. Returns false if
-// the copy couldn't be made (insufficient space, or unrecognized tag), in which
-// case the buffer may be partially used.
-// |buffer|: A mojom buffer used to allocate space for any references from the
-//           union.
-// |in_type_desc|: Describes the pointer and handle fields of the mojom union.
-// |in_union_data|: The unencoded mojom union to be copied.
-// |out_union_data|: Where |in_union_data| should be copied to.
-bool MojomUnion_DeepCopy(struct MojomBuffer* buffer,
-                         const struct MojomTypeDescriptorUnion* in_type_desc,
-                         const struct MojomUnionLayout* in_union_data,
-                         struct MojomUnionLayout* out_union_data);
-
-MOJO_END_EXTERN_C
-
-#endif  // MOJO_PUBLIC_C_INCLUDE_MOJO_BINDINGS_UNION_H_