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hOOt - full text search engine

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24 Feb 2019CPOL17 min read 1.1M   22.5K   388  
Smallest full text search engine (lucene replacement) built from scratch using inverted MGRB bitmap index, highly compact storage, operating in database and document modes
using System;
using System.Collections.Generic;
using System.Text;
using System.Reflection.Emit;
using System.Reflection;
using System.Collections;
using RaptorDB.Common;

namespace fastJSON
{
    internal struct Getters
    {
        public string Name;
        public Reflection.GenericGetter Getter;
        public Type propertyType;
    }

    internal sealed class Reflection
    {
        public readonly static Reflection Instance = new Reflection();
        private Reflection()
        {
        }

        public bool ShowReadOnlyProperties = false;
        internal delegate object GenericSetter(object target, object value);
        internal delegate object GenericGetter(object obj);
        private delegate object CreateObject();

        private SafeDictionary<Type, string> _tyname = new SafeDictionary<Type, string>();
        private SafeDictionary<string, Type> _typecache = new SafeDictionary<string, Type>();
        private SafeDictionary<Type, CreateObject> _constrcache = new SafeDictionary<Type, CreateObject>();
        private SafeDictionary<Type, List<Getters>> _getterscache = new SafeDictionary<Type, List<Getters>>();

        #region [   PROPERTY GET SET   ]
        internal string GetTypeAssemblyName(Type t)
        {
            string val = "";
            if (_tyname.TryGetValue(t, out val))
                return val;
            else
            {
                string s = t.AssemblyQualifiedName;
                _tyname.Add(t, s);
                return s;
            }
        }

        internal Type GetTypeFromCache(string typename)
        {
            Type val = null;
            if (_typecache.TryGetValue(typename, out val))
                return val;
            else
            {
                Type t = Type.GetType(typename);
                _typecache.Add(typename, t);
                return t;
            }
        }

        internal object FastCreateInstance(Type objtype)
        {
            try
            {
                CreateObject c = null;
                if (_constrcache.TryGetValue(objtype, out c))
                {
                    return c();
                }
                else
                {
                    if (objtype.IsClass)
                    {
                        DynamicMethod dynMethod = new DynamicMethod("_", objtype, null);
                        ILGenerator ilGen = dynMethod.GetILGenerator();
                        ilGen.Emit(OpCodes.Newobj, objtype.GetConstructor(Type.EmptyTypes));
                        ilGen.Emit(OpCodes.Ret);
                        c = (CreateObject)dynMethod.CreateDelegate(typeof(CreateObject));
                        _constrcache.Add(objtype, c);
                    }
                    else // structs
                    {
                        DynamicMethod dynMethod = new DynamicMethod("_", typeof(object), null);
                        ILGenerator ilGen = dynMethod.GetILGenerator();
                        var lv = ilGen.DeclareLocal(objtype);
                        ilGen.Emit(OpCodes.Ldloca_S, lv);
                        ilGen.Emit(OpCodes.Initobj, objtype);
                        ilGen.Emit(OpCodes.Ldloc_0);
                        ilGen.Emit(OpCodes.Box, objtype);
                        ilGen.Emit(OpCodes.Ret);
                        c = (CreateObject)dynMethod.CreateDelegate(typeof(CreateObject));
                        _constrcache.Add(objtype, c);
                    }
                    return c();
                }
            }
            catch (Exception exc)
            {
                throw new Exception(string.Format("Failed to fast create instance for type '{0}' from assemebly '{1}'",
                    objtype.FullName, objtype.AssemblyQualifiedName), exc);
            }
        }

        internal static GenericSetter CreateSetField(Type type, FieldInfo fieldInfo)
        {
            Type[] arguments = new Type[2];
            arguments[0] = arguments[1] = typeof(object);

            DynamicMethod dynamicSet = new DynamicMethod("_", typeof(object), arguments, type);

            ILGenerator il = dynamicSet.GetILGenerator();

            if (!type.IsClass) // structs
            {
                var lv = il.DeclareLocal(type);
                il.Emit(OpCodes.Ldarg_0);
                il.Emit(OpCodes.Unbox_Any, type);
                il.Emit(OpCodes.Stloc_0);
                il.Emit(OpCodes.Ldloca_S, lv);
                il.Emit(OpCodes.Ldarg_1);
                if (fieldInfo.FieldType.IsClass)
                    il.Emit(OpCodes.Castclass, fieldInfo.FieldType);
                else
                    il.Emit(OpCodes.Unbox_Any, fieldInfo.FieldType);
                il.Emit(OpCodes.Stfld, fieldInfo);
                il.Emit(OpCodes.Ldloc_0);
                il.Emit(OpCodes.Box, type);
                il.Emit(OpCodes.Ret);
            }
            else
            {
                il.Emit(OpCodes.Ldarg_0);
                il.Emit(OpCodes.Ldarg_1);
                if (fieldInfo.FieldType.IsValueType)
                    il.Emit(OpCodes.Unbox_Any, fieldInfo.FieldType);
                il.Emit(OpCodes.Stfld, fieldInfo);
                il.Emit(OpCodes.Ldarg_0);
                il.Emit(OpCodes.Ret);
            }
            return (GenericSetter)dynamicSet.CreateDelegate(typeof(GenericSetter));
        }

        internal static GenericSetter CreateSetMethod(Type type, PropertyInfo propertyInfo)
        {
            MethodInfo setMethod = propertyInfo.GetSetMethod();
            if (setMethod == null)
                return null;

            Type[] arguments = new Type[2];
            arguments[0] = arguments[1] = typeof(object);

            DynamicMethod setter = new DynamicMethod("_", typeof(object), arguments);
            ILGenerator il = setter.GetILGenerator();

            if (!type.IsClass) // structs
            {
                var lv = il.DeclareLocal(type);
                il.Emit(OpCodes.Ldarg_0);
                il.Emit(OpCodes.Unbox_Any, type);
                il.Emit(OpCodes.Stloc_0);
                il.Emit(OpCodes.Ldloca_S, lv);
                il.Emit(OpCodes.Ldarg_1);
                if (propertyInfo.PropertyType.IsClass)
                    il.Emit(OpCodes.Castclass, propertyInfo.PropertyType);
                else
                    il.Emit(OpCodes.Unbox_Any, propertyInfo.PropertyType);
                il.EmitCall(OpCodes.Call, setMethod, null);
                il.Emit(OpCodes.Ldloc_0);
                il.Emit(OpCodes.Box, type);
            }
            else
            {
                il.Emit(OpCodes.Ldarg_0);
                il.Emit(OpCodes.Castclass, propertyInfo.DeclaringType);
                il.Emit(OpCodes.Ldarg_1);
                if (propertyInfo.PropertyType.IsClass)
                    il.Emit(OpCodes.Castclass, propertyInfo.PropertyType);
                else
                    il.Emit(OpCodes.Unbox_Any, propertyInfo.PropertyType);
                il.EmitCall(OpCodes.Callvirt, setMethod, null);
                il.Emit(OpCodes.Ldarg_0);
            }

            il.Emit(OpCodes.Ret);

            return (GenericSetter)setter.CreateDelegate(typeof(GenericSetter));
        }

        internal static GenericGetter CreateGetField(Type type, FieldInfo fieldInfo)
        {
            DynamicMethod dynamicGet = new DynamicMethod("_", typeof(object), new Type[] { typeof(object) }, type);

            ILGenerator il = dynamicGet.GetILGenerator();

            if (!type.IsClass) // structs
            {
                var lv = il.DeclareLocal(type);
                il.Emit(OpCodes.Ldarg_0);
                il.Emit(OpCodes.Unbox_Any, type);
                il.Emit(OpCodes.Stloc_0);
                il.Emit(OpCodes.Ldloca_S, lv);
                il.Emit(OpCodes.Ldfld, fieldInfo);
                if (fieldInfo.FieldType.IsValueType)
                    il.Emit(OpCodes.Box, fieldInfo.FieldType);
            }
            else
            {
                il.Emit(OpCodes.Ldarg_0);
                il.Emit(OpCodes.Ldfld, fieldInfo);
                if (fieldInfo.FieldType.IsValueType)
                    il.Emit(OpCodes.Box, fieldInfo.FieldType);
            }

            il.Emit(OpCodes.Ret);

            return (GenericGetter)dynamicGet.CreateDelegate(typeof(GenericGetter));
        }

        internal static GenericGetter CreateGetMethod(Type type, PropertyInfo propertyInfo)
        {
            MethodInfo getMethod = propertyInfo.GetGetMethod();
            if (getMethod == null)
                return null;

            DynamicMethod getter = new DynamicMethod("_", typeof(object), new Type[] { typeof(object) }, type);

            ILGenerator il = getter.GetILGenerator();

            if (!type.IsClass) // structs
            {
                var lv = il.DeclareLocal(type);
                il.Emit(OpCodes.Ldarg_0);
                il.Emit(OpCodes.Unbox_Any, type);
                il.Emit(OpCodes.Stloc_0);
                il.Emit(OpCodes.Ldloca_S, lv);
                il.EmitCall(OpCodes.Call, getMethod, null);
                if (propertyInfo.PropertyType.IsValueType)
                    il.Emit(OpCodes.Box, propertyInfo.PropertyType);
            }
            else
            {
                il.Emit(OpCodes.Ldarg_0);
                il.Emit(OpCodes.Castclass, propertyInfo.DeclaringType);
                il.EmitCall(OpCodes.Callvirt, getMethod, null);
                if (propertyInfo.PropertyType.IsValueType)
                    il.Emit(OpCodes.Box, propertyInfo.PropertyType);
            }

            il.Emit(OpCodes.Ret);

            return (GenericGetter)getter.CreateDelegate(typeof(GenericGetter));
        }

        internal List<Getters> GetGetters(Type type)
        {
            List<Getters> val = null;
            if (_getterscache.TryGetValue(type, out val))
                return val;

            PropertyInfo[] props = type.GetProperties(BindingFlags.Public | BindingFlags.Instance);
            List<Getters> getters = new List<Getters>();
            foreach (PropertyInfo p in props)
            {
                if (!p.CanWrite && ShowReadOnlyProperties == false) continue;

                object[] att = p.GetCustomAttributes(typeof(System.Xml.Serialization.XmlIgnoreAttribute), false);
                if (att != null && att.Length > 0)
                    continue;

                GenericGetter g = CreateGetMethod(type, p);
                if (g != null)
                {
                    Getters gg = new Getters();
                    gg.Name = p.Name;
                    gg.Getter = g;
                    gg.propertyType = p.PropertyType;
                    getters.Add(gg);
                }
            }

            FieldInfo[] fi = type.GetFields(BindingFlags.Instance | BindingFlags.Public);
            foreach (var f in fi)
            {
                object[] att = f.GetCustomAttributes(typeof(System.Xml.Serialization.XmlIgnoreAttribute), false);
                if (att != null && att.Length > 0)
                    continue;

                GenericGetter g = CreateGetField(type, f);
                if (g != null)
                {
                    Getters gg = new Getters();
                    gg.Name = f.Name;
                    gg.Getter = g;
                    gg.propertyType = f.FieldType;
                    getters.Add(gg);
                }
            }

            _getterscache.Add(type, getters);
            return getters;
        }

        #endregion
    }
}

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License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


Written By
Architect -
United Kingdom United Kingdom
Mehdi first started programming when he was 8 on BBC+128k machine in 6512 processor language, after various hardware and software changes he eventually came across .net and c# which he has been using since v1.0.
He is formally educated as a system analyst Industrial engineer, but his programming passion continues.

* Mehdi is the 5th person to get 6 out of 7 Platinum's on Code-Project (13th Jan'12)
* Mehdi is the 3rd person to get 7 out of 7 Platinum's on Code-Project (26th Aug'16)

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