[GitHub] jorgebay commented on a change in pull request #1000: TINKERPOP-1942 New Binary Serialization Format

[GitBox <gi...@apache.org>]

jorgebay commented on a change in pull request #1000: TINKERPOP-1942 New Binary Serialization Format
URL: https://github.com/apache/tinkerpop/pull/1000#discussion_r243803794
 
 

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 File path: docs/src/dev/io/graphbinary.asciidoc
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+////
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements.  See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License.  You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+////
+
+[[graphbinary]]
+= GraphBinary
+
+GraphBinary is a binary serialization format suitable for object trees, designed to reduce serialization
+overhead on both the client and the server, as well as limiting the size of the payload that is transmitted over the
+wire.
+
+It describes arbitrary object graphs with a fully-qualified format:
+
+[source]
+----
+{type_code}{type_info}{value_flag}{value}
+----
+
+Where:
+
+* `{type_code}` is a single byte representing the type number.
+* `{type_info}` is an optional sequence of bytes providing additional information of the type represented. This is
+specially useful for representing complex and custom types.
+* `{value_flag}` is a single byte providing information about the value. Flags have the following meaning:
+** `0x01` The value is `null`. When this flag is set, no bytes for `{value}` will be provided.
+* `{value}` is a sequence of bytes which content is determined by the type.
+
+All encodings are big-endian.
+
+Quick examples, using hexadecimal notation to represent each byte:
+
+- `01 00 00 00 00 01`: a 32-bit integer number, that represents the decimal number 1. It’s composed by the
+type_code `0x01`, and empty flag value `0x00` and four bytes to describe the value.
+- `01 00 00 00 00 ff`: a 32-bit integer, representing the number 256.
+- `01 01`: a null value for a 32-bit integer. It’s composed by the type_code `0x01`, and a null flag value `0x01`.
+- `02 00 00 00 00 00 00 00 00 01`: a 64-bit integer number 1. It’s composed by the type_code `0x02`, empty flags and
+eight bytes to describe the value.
+
+== Version 1.0
+
+=== Forward Compatibility
+
+The serialization format supports new types being added without the need to introduce a new version.
+
+Changes to existing types require new revision.
+
+=== Data Type Codes
+
+==== Core Data Types
+
+- `0x01`: Int
+- `0x02`: Long
+- `0x03`: String
+- `0x04`: Date
+- `0x05`: Timestamp
+- `0x06`: Class
+- `0x07`: Double
+- `0x08`: Float
+- `0x09`: List
+- `0x0a`: Map
+- `0x0b`: Set
+- `0x0c`: UUID
+- `0x0d`: Edge
+- `0x0e`: Path
+- `0x0f`: Property
+- `0x10`: TinkerGraph
+- `0x11`: Vertex
+- `0x12`: VertexProperty
+- `0x13`: Barrier
+- `0x14`: Binding
+- `0x15`: Bytecode
+- `0x16`: Cardinality
+- `0x17`: Column
+- `0x18`: Direction
+- `0x19`: Operator
+- `0x1a`: Order
+- `0x1b`: Pick
+- `0x1c`: Pop
+- `0x1d`: Lambda
+- `0x1e`: P
+- `0x1f`: Scope
+- `0x20`: T
+- `0x21`: Traverser
+- `0x22`: BigDecimal
+- `0x23`: BigInteger
+- `0x24`: Byte
+- `0x25`: ByteBuffer
+- `0x26`: Short
+- `0x27`: Boolean
+- `0x28`: TextP
+- `0x29`: TraversalStrategy
+- `0x2a`: BulkSet
+- `0x2b`: Tree
+- `0x2c`: Metrics
+- `0xfe`: Unspecified null object
+- `0x00`: Custom
+
+==== Extended Types
+
+- `0x80`: Char
+- `0x81`: Duration
+- `0x82`: InetAddress
+- `0x83`: Instant
+- `0x84`: LocalDate
+- `0x85`: LocalDateTime
+- `0x86`: LocalTime
+- `0x87`: MonthDay
+- `0x88`: OffsetDateTime
+- `0x89`: OffsetTime
+- `0x8a`: Period
+- `0x8b`: Year
+- `0x8c`: YearMonth
+- `0x8d`: ZonedDateTime
+- `0x8e`: ZoneOffset
+
+=== Null handling
+
+The serialization format defines two ways to represent null values:
+
+- Unspecified null object
+- Fully-qualified null
+
+When a parent type can contain any subtype e.g., a object collection, a `null` value must be represented using the
+"Unspecified Null Object" type code and the null value flag.
+
+In contrast, when the parent type contains a type parameter that must be specified, a `null` value is represented using
+a fully-qualified object using the appropriate type code and type information.
+
+=== Data Type Formats
+
+==== Int
+
+Format: 4-byte two's complement integer.
+
+Example values:
+
+- `00 00 00 01`: 32-bit integer number 1.
+- `00 00 01 01`: 32-bit integer number 256.
+- `ff ff ff ff`: 32-bit integer number -1.
+- `ff ff ff fe`: 32-bit integer number -2.
+
+==== Long
+
+Format: 4-byte two's complement integer.
+
+Example values
+
+- `00 00 00 00 00 00 00 01`: 64-bit integer number 1.
+- `ff ff ff ff ff ff ff fe`: 64-bit integer number -2.
+
+==== String
+
+Format: `{length}{text_value}`
+
+Where:
+
+- `{length}` is an `Int` describing the byte length of the text. Length is a positive number or zero to represent
+the empty string.
+- `{text_value}` is a sequence of bytes representing the string value in UTF8 encoding.
+
+Example values
+
+- `00 00 00 03 61 62 63`: the string 'abc'.
+- `00 00 00 04 61 62 63 64`: the string 'abcd'.
+- `00 00 00 00`: the empty string ''.
+
+==== Date
+
+Format: An 8-byte two's complement signed integer representing a millisecond-precision offset from the unix epoch.
+
+Example values
+
+- `00 00 00 00 00 00 00 00`: The moment in time 1970-01-01T00:00:00.000Z.
+- `ff ff ff ff ff ff ff ff`: The moment in time 1969-12-31T23:59:59.999Z.
+
+==== Timestamp
+
+Format: The same as `Date`.
+
+==== Class
+
+Format: A `String` containing the fqcn.
+
+==== Double
+
+Format: 8 bytes representing IEEE 754 double-precision binary floating-point format.
+
+Example values
+
+- `3f f0 00 00 00 00 00 00`: Double 1
+- `3f 70 00 00 00 00 00 00`: Double 0.00390625
+- `3f b9 99 99 99 99 99 9a`: Double 0.1
+
+==== Float
+
+Format: 4 bytes representing IEEE 754 single-precision binary floating-point format.
+
+Example values
+
+- `3f 80 00 00`: Float 1
+- `3e c0 00 00`: Float 0.375
+
+==== List
+
+An ordered collection of items.
+
+Format: `{length}{item_0}...{item_n}`
+
+Where:
+
+- `{length}` is an `Int` describing the length of the collection.
+- `{item_0}...{item_n}` are the items of the list. `{item_i}` is a fully qualified typed value composed of
+`{type_code}{type_info}{value_flag}{value}`.
+
+==== Set
+
+A collection that contains no duplicate elements.
+
+Format: Same as `List`.
+
+==== Map
+
+A dictionary of keys to values.
+
+Format: `{length}{item_0}...{item_n}`
+
+Where:
+
+- `{length}` is an `Int` describing the length of the map.
+- `{item_0}...{item_n}` are the items of the map. `{item_i}` is sequence of 2 fully qualified typed values one
+representing the key and the following representing the value, each composed of
+`{type_code}{type_info}{value_flag}{value}`.
+
+==== UUID
+
+A 128-bit universally unique identifier.
+
+Format: 16 bytes representing the uuid.
+
+Example
+
+- `00 11 22 33 44 55 66 77 88 99 aa bb cc dd ee ff`: Uuid 00112233-4455-6677-8899-aabbccddeeff.
+
+==== Edge
+
+Format: `{id}{label}{inVId}{inVLabel}{outVId}{outVLabel}{parent}{properties}`
+
+Where:
+
+- `{id}` is a fully qualified typed value composed of `{type_code}{type_info}{value_flag}{value}`.
+- `{label}` is a `String` value.
+- `{inVId}` is a fully qualified typed value composed of `{type_code}{type_info}{value_flag}{value}`.
+- `{inVLabel}` is a `String` value.
+- `{outVId}` is a fully qualified typed value composed of `{type_code}{type_info}{value_flag}{value}`.
+- `{outVLabel}` is a `String` value.
+- `{parent}` is a fully qualified typed value composed of `{type_code}{type_info}{value_flag}{value}` which contains
+the parent `Vertex`. Note that as TinkerPop currently send "references" only, this value will always be `null`.
+- `{properties}` is a fully qualified typed value composed of `{type_code}{type_info}{value_flag}{value}` which contains
+the properties for the edge. Note that as TinkerPop currently send "references" only this value will always be `null`.
+
+==== Path
+
+Format: `{labels}{objects}`
+
+Where:
+
+- `{labels}` is a `List` in which each item is a `Set` of `String`.
+- `{objects}` is a `List` of fully qualified typed values.
+
+==== Property
+
+Format: `{key}{value}{parent}`
+
+Where:
+
+- `{key}` is a `String` value.
+- `{value}`  is a fully qualified typed value composed of `{type_code}{type_info}{value_flag}{value}`.
+- `{parent}` is a fully qualified typed value composed of `{type_code}{type_info}{value_flag}{value}` which is either
+an `Edge` or `VertexProperty`. Note that as TinkerPop currently sends "references" only this value will always be
+`null`.
+
+==== Graph
+
+A collection of vertices and edges. Note that while similar the vertex/edge formats here hold some differences as
+compared to the `Vertex` and `Edge` formats used for standard serialization/deserialiation of a single graph element.
+
+Format: `{vlength}{vertex_0}...{vertex_n}{elength}{edge_0}...{edge_n}`
+
+Where:
+
+- `{vlength}` is an `Int` describing the number of vertices.
+- `{vertex_0}...{vertex_n}` are vertices as described below.
+- `{elength}` is an `Int` describing the number of edges.
+- `{edge_0}...{edge_n}` are edges as described below.
+
+Vertex Format: `{id}{label}{plength}{property_0}...{property_n}`
+
+- `{id}` is a fully qualified typed value composed of `{type_code}{type_info}{value_flag}{value}`.
+- `{label}` is a `String` value.
+- `{plength}` is an `Int` describing the number of properties on the vertex.
+- `{property_0}...{property_n}` are the vertex properties consisting of `{id}{label}{value}{parent}{properties}` as
+defined in `VertexProperty` where the `{parent}` is always `null` and `{properties}` is a `List` of `Property` objects.
+
+Edge Format: `{id}{label}{inVId}{inVLabel}{outVId}{outVLabel}{parent}{properties}`
+
+Where:
+
+- `{id}` is a fully qualified typed value composed of `{type_code}{type_info}{value_flag}{value}`.
+- `{label}` is a `String` value.
+- `{inVId}` is a fully qualified typed value composed of `{type_code}{type_info}{value_flag}{value}`.
+- `{inVLabel}` is always `null`.
+- `{outVId}` is a fully qualified typed value composed of `{type_code}{type_info}{value_flag}{value}`.
+- `{outVLabel}` is always `null`.
+- `{parent}` is always `null`.
+- `{properties}` is a `List` of `Property` objects.
+
+==== Vertex
+
+Format: `{id}{label}{properties}`
+
+Where:
+
+- `{id}` is a fully qualified typed value composed of `{type_code}{type_info}{value_flag}{value}`.
+- `{label}` is a `String` value.
+- `{properties}` is a fully qualified typed value composed of `{type_code}{type_info}{value_flag}{value}` which contains
+properties. Note that as TinkerPop currently send "references" only, this value will always be `null`.
+
+==== VertexProperty
+
+Format: `{id}{label}{value}{parent}{properties}`
+
+Where:
+
+- `{id}` is a fully qualified typed value composed of `{type_code}{type_info}{value_flag}{value}`.
+- `{label}` is a `String` value.
+- `{value}` is a fully qualified typed value composed of `{type_code}{type_info}{value_flag}{value}`.
+- `{parent}` is a fully qualified typed value composed of `{type_code}{type_info}{value_flag}{value}` which contains
+the parent `Vertex`. Note that as TinkerPop currently send "references" only, this value will always be `null`.
+- `{properties}` is a fully qualified typed value composed of `{type_code}{type_info}{value_flag}{value}` which contains
+properties. Note that as TinkerPop currently send "references" only, this value will always be `null`.
+
+==== Barrier
+
+Format: a single `String` representing the enum value.
+
+==== Binding
+
+Format: `{key}{value}`
+
+Where:
+
+- `{key}` is a `String` value.
+- `{value}` is a fully qualified typed value composed of `{type_code}{type_info}{value_flag}{value}`.
+
+==== Bytecode
+
+Format: `{steps_length}{step_0}...{step_n}{sources_length}{source_0}...{source_n}`
 
 Review comment:
   In this case, both (lengths) will be provided so it's basically the same :)

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