// 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.

#ifndef SerializationTag_h
#define SerializationTag_h

namespace blink {

// Serialization format is a sequence of tags followed by zero or more data
// arguments.  Tags always take exactly one byte. A serialized stream first
// begins with a complete VersionTag. If the stream does not begin with a
// VersionTag, we assume that the stream is in format 0.

// This format is private to the implementation of SerializedScriptValue. Do not
// rely on it externally. It is safe to persist a SerializedScriptValue as a
// binary blob, but this code should always be used to interpret it.

// WebCoreStrings are read as (length:uint32_t, string:UTF8[length]).
// RawStrings are read as (length:uint32_t, string:UTF8[length]).
// RawUCharStrings are read as
//     (length:uint32_t, string:UChar[length/sizeof(UChar)]).
// RawFiles are read as
//     (path:WebCoreString, url:WebCoreStrng, type:WebCoreString).
// There is a reference table that maps object references (uint32_t) to
// v8::Values.
// Tokens marked with (ref) are inserted into the reference table and given the
// next object reference ID after decoding.
// All tags except InvalidTag, PaddingTag, ReferenceCountTag, VersionTag,
// GenerateFreshObjectTag and GenerateFreshArrayTag push their results to the
// deserialization stack.
// There is also an 'open' stack that is used to resolve circular references.
// Objects or arrays may contain self-references. Before we begin to deserialize
// the contents of these values, they are first given object reference IDs (by
// GenerateFreshObjectTag/GenerateFreshArrayTag); these reference IDs are then
// used with ObjectReferenceTag to tie the recursive knot.
enum SerializationTag {
  InvalidTag = '!',      // Causes deserialization to fail.
  PaddingTag = '\0',     // Is ignored (but consumed).
  UndefinedTag = '_',    // -> <undefined>
  NullTag = '0',         // -> <null>
  TrueTag = 'T',         // -> <true>
  FalseTag = 'F',        // -> <false>
  StringTag = 'S',       // string:RawString -> string
  StringUCharTag = 'c',  // string:RawUCharString -> string
  Int32Tag = 'I',        // value:ZigZag-encoded int32 -> Integer
  Uint32Tag = 'U',       // value:uint32_t -> Integer
  DateTag = 'D',         // value:double -> Date (ref)
  MessagePortTag = 'M',  // index:int -> MessagePort. Fills the result with
                         // transferred MessagePort.
  NumberTag = 'N',       // value:double -> Number
  BlobTag = 'b',  // uuid:WebCoreString, type:WebCoreString, size:uint64_t ->
                  // Blob (ref)
  BlobIndexTag = 'i',      // index:int32_t -> Blob (ref)
  FileTag = 'f',           // file:RawFile -> File (ref)
  FileIndexTag = 'e',      // index:int32_t -> File (ref)
  DOMFileSystemTag = 'd',  // type:int32_t, name:WebCoreString,
                           // uuid:WebCoreString -> FileSystem (ref)
  FileListTag =
      'l',  // length:uint32_t, files:RawFile[length] -> FileList (ref)
  FileListIndexTag =
      'L',  // length:uint32_t, files:int32_t[length] -> FileList (ref)
  ImageDataTag = '#',  // width:uint32_t, height:uint32_t,
                       // pixelDataLength:uint32_t, data:byte[pixelDataLength]
                       // -> ImageData (ref)
  // numProperties:uint32_t -> pops the last object from the open stack; fills
  // it with the last numProperties name,value pairs pushed onto the
  // deserialization stack
  ObjectTag = '{',
  // numProperties:uint32_t, length:uint32_t -> pops the last object from the
  // open stack; fills it with the last numProperties name,value pairs pushed
  // onto the deserialization stack
  SparseArrayTag = '@',
  // numProperties:uint32_t, length:uint32_t -> pops the last object from the
  // open stack; fills it with the last length elements and numProperties
  // name,value pairs pushed onto deserialization stack
  DenseArrayTag = '$',
  RegExpTag = 'R',  // pattern:RawString, flags:uint32_t -> RegExp (ref)
  ArrayBufferTag =
      'B',  // byteLength:uint32_t, data:byte[byteLength] -> ArrayBuffer (ref)
  ArrayBufferTransferTag =
      't',  // index:uint32_t -> ArrayBuffer. For ArrayBuffer transfer
  ImageBitmapTag = 'g',  // size:uint32_t, data:byte[size] -> ImageBitmap (ref)
  ImageBitmapTransferTag =
      'G',  // index:uint32_t -> ImageBitmap. For ImageBitmap transfer
  OffscreenCanvasTransferTag = 'H',  // index, width, height, id:uint32_t ->
                                     // OffscreenCanvas. For OffscreenCanvas
                                     // transfer
  // subtag:byte, byteOffset:uint32_t, byteLength:uint32_t -> ArrayBufferView
  // (ref).  Consumes an ArrayBuffer from the top of the deserialization stack.
  ArrayBufferViewTag = 'V',
  SharedArrayBufferTransferTag = 'u',  // index:uint32_t -> SharedArrayBuffer.
                                       // For SharedArrayBuffer transfer
  WasmModuleTag = 'W',
  CryptoKeyTag = 'K',  // subtag:byte, props, usages:uint32_t,
                       // keyDataLength:uint32_t, keyData:byte[keyDataLength]
  //                 If subtag=AesKeyTag:
  //                     props = keyLengthBytes:uint32_t, algorithmId:uint32_t
  //                 If subtag=HmacKeyTag:
  //                     props = keyLengthBytes:uint32_t, hashId:uint32_t
  //                 If subtag=RsaHashedKeyTag:
  //                     props = algorithmId:uint32_t, type:uint32_t,
  //                     modulusLengthBits:uint32_t,
  //                     publicExponentLength:uint32_t,
  //                     publicExponent:byte[publicExponentLength],
  //                     hashId:uint32_t
  //                 If subtag=EcKeyTag:
  //                     props = algorithmId:uint32_t, type:uint32_t,
  //                     namedCurve:uint32_t
  RTCCertificateTag = 'k',   // length:uint32_t, pemPrivateKey:WebCoreString,
                             // pemCertificate:WebCoreString
  ObjectReferenceTag = '^',  // ref:uint32_t -> reference table[ref]
  GenerateFreshObjectTag = 'o',  // -> empty object allocated an object ID and
                                 // pushed onto the open stack (ref)
  GenerateFreshSparseArrayTag = 'a',  // length:uint32_t -> empty array[length]
                                      // allocated an object ID and pushed onto
                                      // the open stack (ref)
  GenerateFreshDenseArrayTag = 'A',   // length:uint32_t -> empty array[length]
                                      // allocated an object ID and pushed onto
                                      // the open stack (ref)
  ReferenceCountTag = '?',  // refTableSize:uint32_t -> If the reference table
                            // is not refTableSize big, fails.
  StringObjectTag = 's',    //  string:RawString -> new String(string) (ref)
  NumberObjectTag = 'n',    // value:double -> new Number(value) (ref)
  TrueObjectTag = 'y',      // new Boolean(true) (ref)
  FalseObjectTag = 'x',     // new Boolean(false) (ref)
  CompositorProxyTag =
      'C',  // elementId:uint64_t, bitfields:uint32_t -> CompositorProxy (ref)
  MapTag = ':',  // length:uint32_t -> pops the last object from the open stack
                 // (it will be a Map);
  //                              fills it with the last length elements pushed
  //                              onto the deserialization stack, treating them
  //                              as key/value pairs and passing them to
  //                              Map::Set;
  //                              length must be an even number.
  SetTag = ',',  // length:uint32_t -> pops the last object from the open stack
                 // (it will be a Set);
  //                              fills it with the last length elements pushed
  //                              onto the deserialization stack, using Set::Add
  GenerateFreshMapTag = ';',   // -> empty Map allocated an object ID and pushed
                               // onto the open stack (ref)
  GenerateFreshSetTag = '\'',  // -> empty Set allocated an object ID and pushed
                               // onto the open stack (ref)
  VersionTag = 0xFF  // version:uint32_t -> Uses this as the file version.
};

enum ArrayBufferViewSubTag {
  ByteArrayTag = 'b',
  UnsignedByteArrayTag = 'B',
  UnsignedByteClampedArrayTag = 'C',
  ShortArrayTag = 'w',
  UnsignedShortArrayTag = 'W',
  IntArrayTag = 'd',
  UnsignedIntArrayTag = 'D',
  FloatArrayTag = 'f',
  DoubleArrayTag = 'F',
  DataViewTag = '?'
};

}  // namespace blink

#endif