Writable Json DOM - JsonNumber implementation and tests (#39917)

* Json prototype (#1)

Basic API for Json writable DOM with scenarios including collection initialization, accessing and modifying Json nodes.

* Json prototype - transformation API  (#2)

* transformation API added
* assertions to existing scenarios added

* Json prototype (#1)

Basic API for Json writable DOM with scenarios including collection initialization, accessing and modifying Json nodes.

* Json prototype - transformation API  (#2)

* transformation API added
* assertions to existing scenarios added

* JsonNumber implementation and tests (#3)

* IEquatables added
* JsonNumber implementation and unit tests added
* pragmas deleted
* review comments included, more tests added
* decimal support added to JsonNumber
* decimal support added to JsonArray and JsonObject

* all unimplemented classes and methods with accompanying tests removed

* First part of documentation added

* documentation completed

* missing exceptions added

* JsonElement changes removed

* part of the review comments included

* work on review comments

* code refactor

* more decimal tests added using MemberData

* more decimal tests added using MemberData

* more test cases added

* equals summary adjusted, equals tests added

* more Equals tests added, GetHashCode tests added, minor changes

* scientifing notation support added, rational numbers tests fixes

* rational overflow tests added

* ulong maxvalue tests added to rational types

* presision problems fixes

* exception strings fixed

* CI failing fixes (hopefully), review comments included

* missing == tests added to achieve 100% branch coverage

* review comments included

* trailing whitespaces fixes

* equals comments added

* equals object refactored to call quals json number

* merge fix

src/System.Text.Json/ref/System.Text.Json.cs

@@ -156,6 +156,97 @@ protected JsonNamingPolicy() { }
         public static System.Text.Json.JsonNamingPolicy CamelCase { get { throw null; } }
         public abstract string ConvertName(string name);
     }
+    public abstract partial class JsonNode
+    {
+        internal JsonNode() { }
+    }
+    public sealed partial class JsonNumber : System.Text.Json.JsonNode, System.IEquatable<System.Text.Json.JsonNumber>
+    {
+        public JsonNumber() { }
+        public JsonNumber(byte value) { }
+        public JsonNumber(decimal value) { }
+        public JsonNumber(double value) { }
+        public JsonNumber(short value) { }
+        public JsonNumber(int value) { }
+        public JsonNumber(long value) { }
+        [System.CLSCompliantAttribute(false)]
+        public JsonNumber(sbyte value) { }
+        public JsonNumber(float value) { }
+        public JsonNumber(string value) { }
+        [System.CLSCompliantAttribute(false)]
+        public JsonNumber(ushort value) { }
+        [System.CLSCompliantAttribute(false)]
+        public JsonNumber(uint value) { }
+        [System.CLSCompliantAttribute(false)]
+        public JsonNumber(ulong value) { }
+        public override bool Equals(object obj) { throw null; }
+        public bool Equals(System.Text.Json.JsonNumber other) { throw null; }
+        public byte GetByte() { throw null; }
+        public decimal GetDecimal() { throw null; }
+        public double GetDouble() { throw null; }
+        public override int GetHashCode() { throw null; }
+        public short GetInt16() { throw null; }
+        public int GetInt32() { throw null; }
+        public long GetInt64() { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public sbyte GetSByte() { throw null; }
+        public float GetSingle() { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public ushort GetUInt16() { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public uint GetUInt32() { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public ulong GetUInt64() { throw null; }
+        public static bool operator ==(System.Text.Json.JsonNumber left, System.Text.Json.JsonNumber right) { throw null; }
+        public static implicit operator System.Text.Json.JsonNumber (byte value) { throw null; }
+        public static implicit operator System.Text.Json.JsonNumber (decimal value) { throw null; }
+        public static implicit operator System.Text.Json.JsonNumber (double value) { throw null; }
+        public static implicit operator System.Text.Json.JsonNumber (short value) { throw null; }
+        public static implicit operator System.Text.Json.JsonNumber (int value) { throw null; }
+        public static implicit operator System.Text.Json.JsonNumber (long value) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public static implicit operator System.Text.Json.JsonNumber (sbyte value) { throw null; }
+        public static implicit operator System.Text.Json.JsonNumber (float value) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public static implicit operator System.Text.Json.JsonNumber (ushort value) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public static implicit operator System.Text.Json.JsonNumber (uint value) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public static implicit operator System.Text.Json.JsonNumber (ulong value) { throw null; }
+        public static bool operator !=(System.Text.Json.JsonNumber left, System.Text.Json.JsonNumber right) { throw null; }
+        public void SetByte(byte value) { }
+        public void SetDecimal(decimal value) { }
+        public void SetDouble(double value) { }
+        public void SetFormattedValue(string value) { }
+        public void SetInt16(short value) { }
+        public void SetInt32(int value) { }
+        public void SetInt64(long value) { }
+        [System.CLSCompliantAttribute(false)]
+        public void SetSByte(sbyte value) { }
+        public void SetSingle(float value) { }
+        [System.CLSCompliantAttribute(false)]
+        public void SetUInt16(ushort value) { }
+        [System.CLSCompliantAttribute(false)]
+        public void SetUInt32(uint value) { }
+        [System.CLSCompliantAttribute(false)]
+        public void SetUInt64(ulong value) { }
+        public override string ToString() { throw null; }
+        public bool TryGetByte(out byte value) { throw null; }
+        public bool TryGetDecimal(out decimal value) { throw null; }
+        public bool TryGetDouble(out double value) { throw null; }
+        public bool TryGetInt16(out short value) { throw null; }
+        public bool TryGetInt32(out int value) { throw null; }
+        public bool TryGetInt64(out long value) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public bool TryGetSByte(out sbyte value) { throw null; }
+        public bool TryGetSingle(out float value) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public bool TryGetUInt16(out ushort value) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public bool TryGetUInt32(out uint value) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public bool TryGetUInt64(out ulong value) { throw null; }
+    }
     public readonly partial struct JsonProperty
     {
         private readonly object _dummy;

src/System.Text.Json/src/Resources/Strings.resx

@@ -426,4 +426,7 @@
   <data name="SerializerCycleDetected" xml:space="preserve">
     <value>A possible object cycle was detected which is not supported. This can either be due to a cycle or if the object depth is larger than the maximum allowed depth of {0}.</value>
   </data>
-</root>
+  <data name="EmptyStringToInitializeNumber" xml:space="preserve">
+    <value>Expected a number, but instead got empty string.</value>
+  </data>
+</root>

src/System.Text.Json/src/System.Text.Json.csproj

@@ -208,4 +208,8 @@
     <Reference Include="System.Threading.Tasks" />
     <Reference Include="System.Threading.Tasks.Extensions" />
   </ItemGroup>
+  <ItemGroup>
+    <Compile Include="System\Text\Json\Node\JsonNode.cs" />
+    <Compile Include="System\Text\Json\Node\JsonNumber.cs" />
+  </ItemGroup>
 </Project>

src/System.Text.Json/src/System/Text/Json/Node/JsonNode.cs

@@ -0,0 +1,14 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace System.Text.Json
+{
+    /// <summary>
+    ///   The base class that represents a single node within a JSON document.
+    /// </summary>
+    public abstract class JsonNode
+    {
+        private protected JsonNode() { }
+    }
+}