// ==++==
// 
//   Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// ==--==
/*============================================================
**
** Class:  Object
**
**
** Object is the root class for all CLR objects.  This class
** defines only the basics.
**
** 
===========================================================*/

namespace System {
    using System;
    using System.Runtime;
    using System.Runtime.InteropServices;
    using System.Runtime.CompilerServices;
    using System.Runtime.ConstrainedExecution;
    using System.Runtime.Versioning;
    using System.Diagnostics.Contracts;
    using CultureInfo = System.Globalization.CultureInfo;
    using FieldInfo = System.Reflection.FieldInfo;
    using BindingFlags = System.Reflection.BindingFlags;
#if FEATURE_REMOTING        
    using RemotingException = System.Runtime.Remoting.RemotingException;    
#endif
// The Object is the root class for all object in the CLR System. Object 
// is the super class for all other CLR objects and provide a set of methods and low level
// services to subclasses.  These services include object synchronization and support for clone
// operations.
// 
 //This class contains no data and does not need to be serializable 
[Serializable]
[ClassInterface(ClassInterfaceType.AutoDual)]
[System.Runtime.InteropServices.ComVisible(true)]
public class Object
{
    // Creates a new instance of an Object.
    [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
    [System.Runtime.Versioning.NonVersionable]
    public Object()
    {            
    }
            
    // Returns a String which represents the object instance.  The default
    // for an object is to return the fully qualified name of the class.
    // 
    public virtual String ToString()
    {
        return GetType().ToString();
    }
    
    // Returns a boolean indicating if the passed in object obj is 
    // Equal to this.  Equality is defined as object equality for reference
    // types and bitwise equality for value types using a loader trick to
    // replace Equals with EqualsValue for value types).
    // 
    
    public virtual bool Equals(Object obj)
    {
        return RuntimeHelpers.Equals(this, obj);
    }

    public static bool Equals(Object objA, Object objB) 
    {
        if (objA==objB) {
            return true;
        }
        if (objA==null || objB==null) {
            return false;
        }
        return objA.Equals(objB);
    }

    [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
    [System.Runtime.Versioning.NonVersionable]
    public static bool ReferenceEquals (Object objA, Object objB) {
        return objA == objB;
    }
    
    // GetHashCode is intended to serve as a hash function for this object.
    // Based on the contents of the object, the hash function will return a suitable
    // value with a relatively random distribution over the various inputs.
    //
    // The default implementation returns the sync block index for this instance.
    // Calling it on the same object multiple times will return the same value, so
    // it will technically meet the needs of a hash function, but it's less than ideal.
    // Objects (& especially value classes) should override this method.
    // 
    public virtual int GetHashCode()
    {
        return RuntimeHelpers.GetHashCode(this);
    }
    
    // Returns a Type object which represent this object instance.
    // 
    [System.Security.SecuritySafeCritical]  // auto-generated
    [Pure]
    [ResourceExposure(ResourceScope.None)]
    [MethodImplAttribute(MethodImplOptions.InternalCall)]
    public extern Type GetType();

    // Allow an object to free resources before the object is reclaimed by the GC.
    // 
    [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
    [System.Runtime.Versioning.NonVersionable]
    ~Object()
    {
    }
    
    // Returns a new object instance that is a memberwise copy of this 
    // object.  This is always a shallow copy of the instance. The method is protected
    // so that other object may only call this method on themselves.  It is entended to
    // support the ICloneable interface.
    // 
    [System.Security.SecuritySafeCritical]  // auto-generated
    [ResourceExposure(ResourceScope.None)]
    [MethodImplAttribute(MethodImplOptions.InternalCall)]
    protected extern Object MemberwiseClone();
    
   
    // Sets the value specified in the variant on the field
    // 
    [System.Security.SecurityCritical]  // auto-generated
    private void FieldSetter(String typeName, String fieldName, Object val)
    {
        Contract.Requires(typeName != null);
        Contract.Requires(fieldName != null);

        // Extract the field info object
        FieldInfo fldInfo = GetFieldInfo(typeName, fieldName);

        if (fldInfo.IsInitOnly)
            throw new FieldAccessException(Environment.GetResourceString("FieldAccess_InitOnly"));

        // Make sure that the value is compatible with the type
        // of field
#if FEATURE_REMOTING        
        System.Runtime.Remoting.Messaging.Message.CoerceArg(val, fldInfo.FieldType);    
#else
        Type pt=fldInfo.FieldType;
        if (pt.IsByRef) 
        {
            pt = pt.GetElementType();
        }
    
        if (!pt.IsInstanceOfType(val))
        {
            val = Convert.ChangeType(val, pt, CultureInfo.InvariantCulture);
        }

#endif

        // Set the value            
        fldInfo.SetValue(this, val);
    }
    
    // Gets the value specified in the variant on the field
    // 
    private void FieldGetter(String typeName, String fieldName, ref Object val)
    {
        Contract.Requires(typeName != null);
        Contract.Requires(fieldName != null);

        // Extract the field info object
        FieldInfo fldInfo = GetFieldInfo(typeName, fieldName);

        // Get the value
        val = fldInfo.GetValue(this);            
    }

    // Gets the field info object given the type name and field name.
    // 
    private FieldInfo GetFieldInfo(String typeName, String fieldName)
    {
        Contract.Requires(typeName != null);
        Contract.Requires(fieldName != null);
        Contract.Ensures(Contract.Result<FieldInfo>() != null);

        Type t = GetType();
        while(null != t)
        {
            if(t.FullName.Equals(typeName))
            {
                break;
            }

            t = t.BaseType;
        }
        
        if (null == t)
        {
#if FEATURE_REMOTING         
            throw new RemotingException(String.Format(
                CultureInfo.CurrentCulture, Environment.GetResourceString("Remoting_BadType"),
                                              typeName));
#else
            throw new ArgumentException();
#endif
        }

        FieldInfo fldInfo = t.GetField(fieldName, BindingFlags.Public | 
                                                  BindingFlags.Instance | 
                                                  BindingFlags.IgnoreCase);
        if(null == fldInfo)
        {
#if FEATURE_REMOTING 
            throw new RemotingException(String.Format(
                CultureInfo.CurrentCulture, Environment.GetResourceString("Remoting_BadField"),
                                              fieldName, typeName));            
#else
            throw new ArgumentException();
#endif

        }
        
        return fldInfo;
    }
}


// Internal methodtable used to instantiate the "canonical" methodtable for generic instantiations.
// The name "__Canon" will never been seen by users but it will appear a lot in debugger stack traces
// involving generics so it is kept deliberately short as to avoid being a nuisance.

[Serializable]
[ClassInterface(ClassInterfaceType.AutoDual)]
[System.Runtime.InteropServices.ComVisible(true)]
internal class __Canon
{
}

}