|
//---------------------------------------------------------------------
// <copyright file="DotExpr.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//
// @owner Microsoft
// @backupOwner Microsoft
//---------------------------------------------------------------------
namespace System.Data.Common.EntitySql.AST
{
using System;
using System.Globalization;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
/// <summary>
/// Represents dotExpr: expr.Identifier
/// </summary>
internal sealed class DotExpr : Node
{
private readonly Node _leftExpr;
private readonly Identifier _identifier;
private bool? _isMultipartIdentifierComputed;
private string[] _names;
/// <summary>
/// initializes
/// </summary>
internal DotExpr(Node leftExpr, Identifier id)
{
_leftExpr = leftExpr;
_identifier = id;
}
/// <summary>
/// For the following expression: "a.b.c.d", Left returns "a.b.c".
/// </summary>
internal Node Left
{
get { return _leftExpr; }
}
/// <summary>
/// For the following expression: "a.b.c.d", Identifier returns "d".
/// </summary>
internal Identifier Identifier
{
get { return _identifier; }
}
/// <summary>
/// Returns true if all parts of this expression are identifiers like in "a.b.c",
/// false for expressions like "FunctionCall().a.b.c".
/// </summary>
internal bool IsMultipartIdentifier(out string[] names)
{
if (_isMultipartIdentifierComputed.HasValue)
{
names = _names;
return _isMultipartIdentifierComputed.Value;
}
_names = null;
Identifier leftIdenitifier = _leftExpr as Identifier;
if (leftIdenitifier != null)
{
_names = new string[] { leftIdenitifier.Name, _identifier.Name };
}
DotExpr leftDotExpr = _leftExpr as DotExpr;
string[] leftNames;
if (leftDotExpr != null && leftDotExpr.IsMultipartIdentifier(out leftNames))
{
_names = new string[leftNames.Length + 1];
leftNames.CopyTo(_names, 0);
_names[_names.Length - 1] = _identifier.Name;
}
Debug.Assert(_names == null || _names.Length > 0, "_names must be null or non-empty");
_isMultipartIdentifierComputed = _names != null;
names = _names;
return _isMultipartIdentifierComputed.Value;
}
}
}
|