RaspberryIO_26/Swan.Lite/Formatters/Json.Serializer.cs
2019-12-08 19:54:52 +01:00

332 lines
12 KiB
C#

#nullable enable
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Text;
namespace Swan.Formatters {
/// <summary>
/// A very simple, light-weight JSON library written by Mario
/// to teach Geo how things are done
///
/// This is an useful helper for small tasks but it doesn't represent a full-featured
/// serializer such as the beloved Json.NET.
/// </summary>
public partial class Json {
/// <summary>
/// A simple JSON serializer.
/// </summary>
private class Serializer {
#region Private Declarations
private static readonly Dictionary<Int32, String> IndentStrings = new Dictionary<global::System.Int32, global::System.String>();
private readonly SerializerOptions? _options;
private readonly String _result;
private readonly StringBuilder? _builder;
private readonly String? _lastCommaSearch;
#endregion
#region Constructors
/// <summary>
/// Initializes a new instance of the <see cref="Serializer" /> class.
/// </summary>
/// <param name="obj">The object.</param>
/// <param name="depth">The depth.</param>
/// <param name="options">The options.</param>
private Serializer(Object? obj, Int32 depth, SerializerOptions options) {
if(depth > 20) {
throw new InvalidOperationException("The max depth (20) has been reached. Serializer can not continue.");
}
// Basic Type Handling (nulls, strings, number, date and bool)
this._result = ResolveBasicType(obj);
if(!String.IsNullOrWhiteSpace(this._result)) {
return;
}
this._options = options;
// Handle circular references correctly and avoid them
if(options.IsObjectPresent(obj!)) {
this._result = $"{{ \"$circref\": \"{Escape(obj!.GetHashCode().ToStringInvariant(), false)}\" }}";
return;
}
// At this point, we will need to construct the object with a StringBuilder.
this._lastCommaSearch = FieldSeparatorChar + (this._options.Format ? Environment.NewLine : String.Empty);
this._builder = new StringBuilder();
this._result = obj switch
{
IDictionary itemsZero when itemsZero.Count == 0 => EmptyObjectLiteral,
IDictionary items => this.ResolveDictionary(items, depth),
IEnumerable enumerableZero when !enumerableZero.Cast<Object>().Any() => EmptyArrayLiteral,
IEnumerable enumerableBytes when enumerableBytes is Byte[] bytes => Serialize(bytes.ToBase64(), depth, this._options),
IEnumerable enumerable => this.ResolveEnumerable(enumerable, depth),
_ => this.ResolveObject(obj!, depth)
};
}
internal static String Serialize(Object? obj, Int32 depth, SerializerOptions options) => new Serializer(obj, depth, options)._result;
#endregion
#region Helper Methods
private static String ResolveBasicType(Object? obj) {
switch(obj) {
case null:
return NullLiteral;
case String s:
return Escape(s, true);
case Boolean b:
return b ? TrueLiteral : FalseLiteral;
case Type _:
case Assembly _:
case MethodInfo _:
case PropertyInfo _:
case EventInfo _:
return Escape(obj.ToString()!, true);
case DateTime d:
return $"{StringQuotedChar}{d:s}{StringQuotedChar}";
default:
Type targetType = obj.GetType();
if(!Definitions.BasicTypesInfo.Value.ContainsKey(targetType)) {
return String.Empty;
}
String escapedValue = Escape(Definitions.BasicTypesInfo.Value[targetType].ToStringInvariant(obj), false);
return Decimal.TryParse(escapedValue, out _) ? $"{escapedValue}" : $"{StringQuotedChar}{escapedValue}{StringQuotedChar}";
}
}
private static Boolean IsNonEmptyJsonArrayOrObject(String serialized) {
if(serialized == EmptyObjectLiteral || serialized == EmptyArrayLiteral) {
return false;
}
// find the first position the character is not a space
return serialized.Where(c => c != ' ').Select(c => c == OpenObjectChar || c == OpenArrayChar).FirstOrDefault();
}
private static String Escape(String str, Boolean quoted) {
if(str == null) {
return String.Empty;
}
StringBuilder builder = new StringBuilder(str.Length * 2);
if(quoted) {
_ = builder.Append(StringQuotedChar);
}
Escape(str, builder);
if(quoted) {
_ = builder.Append(StringQuotedChar);
}
return builder.ToString();
}
private static void Escape(String str, StringBuilder builder) {
foreach(Char currentChar in str) {
switch(currentChar) {
case '\\':
case '"':
case '/':
_ = builder
.Append('\\')
.Append(currentChar);
break;
case '\b':
_ = builder.Append("\\b");
break;
case '\t':
_ = builder.Append("\\t");
break;
case '\n':
_ = builder.Append("\\n");
break;
case '\f':
_ = builder.Append("\\f");
break;
case '\r':
_ = builder.Append("\\r");
break;
default:
if(currentChar < ' ') {
Byte[] escapeBytes = BitConverter.GetBytes((UInt16)currentChar);
if(BitConverter.IsLittleEndian == false) {
Array.Reverse(escapeBytes);
}
_ = builder.Append("\\u")
.Append(escapeBytes[1].ToString("X").PadLeft(2, '0'))
.Append(escapeBytes[0].ToString("X").PadLeft(2, '0'));
} else {
_ = builder.Append(currentChar);
}
break;
}
}
}
private Dictionary<String, Object?> CreateDictionary(Dictionary<String, MemberInfo> fields, String targetType, Object target) {
// Create the dictionary and extract the properties
global::System.Collections.Generic.Dictionary<global::System.String, global::System.Object?> objectDictionary = new Dictionary<global::System.String, global::System.Object?>();
if(String.IsNullOrWhiteSpace(this._options?.TypeSpecifier) == false) {
objectDictionary[this._options?.TypeSpecifier!] = targetType;
}
foreach(global::System.Collections.Generic.KeyValuePair<global::System.String, global::System.Reflection.MemberInfo> field in fields) {
// Build the dictionary using property names and values
// Note: used to be: property.GetValue(target); but we would be reading private properties
try {
objectDictionary[field.Key] = field.Value is PropertyInfo property ? property.GetCacheGetMethod((Boolean)(this._options?.IncludeNonPublic)!)?.Invoke(target) : (field.Value as FieldInfo)?.GetValue(target);
} catch {
/* ignored */
}
}
return objectDictionary;
}
private String ResolveDictionary(IDictionary items, Int32 depth) {
this.Append(OpenObjectChar, depth);
this.AppendLine();
// Iterate through the elements and output recursively
Int32 writeCount = 0;
foreach(Object? key in items.Keys) {
// Serialize and append the key (first char indented)
this.Append(StringQuotedChar, depth + 1);
Escape(key?.ToString()!, this._builder!);
_ = this._builder?.Append(StringQuotedChar).Append(ValueSeparatorChar).Append(" ");
// Serialize and append the value
String serializedValue = Serialize(items[key!], depth + 1, this._options!);
if(IsNonEmptyJsonArrayOrObject(serializedValue)) {
this.AppendLine();
}
this.Append(serializedValue, 0);
// Add a comma and start a new line -- We will remove the last one when we are done writing the elements
this.Append(FieldSeparatorChar, 0);
this.AppendLine();
writeCount++;
}
// Output the end of the object and set the result
this.RemoveLastComma();
this.Append(CloseObjectChar, writeCount > 0 ? depth : 0);
return this._builder!.ToString();
}
private String ResolveObject(Object target, Int32 depth) {
Type targetType = target.GetType();
if(targetType.IsEnum) {
return Convert.ToInt64(target, System.Globalization.CultureInfo.InvariantCulture).ToString();
}
global::System.Collections.Generic.Dictionary<global::System.String, global::System.Reflection.MemberInfo> fields = this._options!.GetProperties(targetType);
if(fields.Count == 0 && String.IsNullOrWhiteSpace(this._options.TypeSpecifier)) {
return EmptyObjectLiteral;
}
// If we arrive here, then we convert the object into a
// dictionary of property names and values and call the serialization
// function again
global::System.Collections.Generic.Dictionary<global::System.String, global::System.Object?> objectDictionary = this.CreateDictionary(fields, targetType.ToString(), target);
return Serialize(objectDictionary, depth, this._options);
}
private String ResolveEnumerable(IEnumerable target, Int32 depth) {
// Cast the items as a generic object array
global::System.Collections.Generic.IEnumerable<global::System.Object> items = target.Cast<global::System.Object>();
this.Append(OpenArrayChar, depth);
this.AppendLine();
// Iterate through the elements and output recursively
Int32 writeCount = 0;
foreach(Object entry in items) {
String serializedValue = Serialize(entry, depth + 1, this._options!);
if(IsNonEmptyJsonArrayOrObject(serializedValue)) {
this.Append(serializedValue, 0);
} else {
this.Append(serializedValue, depth + 1);
}
this.Append(FieldSeparatorChar, 0);
this.AppendLine();
writeCount++;
}
// Output the end of the array and set the result
this.RemoveLastComma();
this.Append(CloseArrayChar, writeCount > 0 ? depth : 0);
return this._builder!.ToString();
}
private void SetIndent(Int32 depth) {
if(this._options!.Format == false || depth <= 0) {
return;
}
_ = this._builder!.Append(IndentStrings.GetOrAdd(depth, x => new String(' ', x * 4)));
}
/// <summary>
/// Removes the last comma in the current string builder.
/// </summary>
private void RemoveLastComma() {
if(this._builder!.Length < this._lastCommaSearch!.Length) {
return;
}
if(this._lastCommaSearch.Where((t, i) => this._builder[this._builder.Length - this._lastCommaSearch.Length + i] != t).Any()) {
return;
}
// If we got this far, we simply remove the comma character
_ = this._builder.Remove(this._builder.Length - this._lastCommaSearch.Length, 1);
}
private void Append(String text, Int32 depth) {
this.SetIndent(depth);
_ = this._builder!.Append(text);
}
private void Append(Char text, Int32 depth) {
this.SetIndent(depth);
_ = this._builder!.Append(text);
}
private void AppendLine() {
if(this._options!.Format == false) {
return;
}
_ = this._builder!.Append(Environment.NewLine);
}
#endregion
}
}
}