Code:
/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / Objects / Span.cs / 1305376 / Span.cs
//---------------------------------------------------------------------- //// Copyright (c) Microsoft Corporation. All rights reserved. // // // @owner [....] // @backupOwner [....] //--------------------------------------------------------------------- using System; using System.Collections; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Data.Common; using System.Data.Metadata; using System.Data.Metadata.Edm; using System.Data.Objects.DataClasses; using System.Diagnostics; using System.Reflection; using System.Text.RegularExpressions; using System.Text; using System.Data.Objects.Internal; namespace System.Data.Objects { ////// A collection of paths to determine which entities are spanned into a query. /// internal sealed class Span { private List_spanList; private string _cacheKey; internal Span() { _spanList = new List (); } /// /// The list of paths that should be spanned into the query /// internal ListSpanList { get { return _spanList; } } /// /// Checks whether relationship span needs to be performed. Currently this is only when the query is /// not using MergeOption.NoTracking. /// /// ///True if the query needs a relationship span rewrite internal static bool RequiresRelationshipSpan(MergeOption mergeOption) { return (mergeOption != MergeOption.NoTracking); } ////// Includes the specified span path in the specified span instance and returns the updated span instance. /// If /// The span instance to which the include path should be added. May be null /// The include path to add ///is null, a new span instance is constructed and returned that contains /// the specified include path. /// A non-null span instance that contains the specified include path in addition to any paths ut already contained internal static Span IncludeIn(Span spanToIncludeIn, string pathToInclude) { if (null == spanToIncludeIn) { spanToIncludeIn = new Span(); } spanToIncludeIn.Include(pathToInclude); return spanToIncludeIn; } ////// Returns a span instance that is the union of the two specified span instances. /// If /// The first span instance from which to include span paths; may beand are both null , /// thennull is returned. /// Ifor is null, but the remaining argument is non-null, /// then the non-null argument is returned. /// If neither nor are null, a new span instance is returned /// that contains the merged span paths from both. /// null /// The second span instance from which to include span paths; may benull ///A span instance representing the union of the two arguments; may be internal static Span CopyUnion(Span span1, Span span2) { if (null == span1) { return span2; } if (null == span2) { return span1; } Span retSpan = span1.Clone(); foreach (SpanPath path in span2.SpanList) { retSpan.AddSpanPath(path); } return retSpan; } internal string GetCacheKey() { if (null == _cacheKey) { if (_spanList.Count > 0) { // If there is only a single Include path with a single property, // then simply use the property name as the cache key rather than // creating any new strings. if (_spanList.Count == 1 && _spanList[0].Navigations.Count == 1) { _cacheKey = _spanList[0].Navigations[0]; } else { StringBuilder keyBuilder = new StringBuilder(); for (int pathIdx = 0; pathIdx < _spanList.Count; pathIdx++) { if (pathIdx > 0) { keyBuilder.Append(";"); } SpanPath thisPath = _spanList[pathIdx]; keyBuilder.Append(thisPath.Navigations[0]); for (int propIdx = 1; propIdx < thisPath.Navigations.Count; propIdx++) { keyBuilder.Append("."); keyBuilder.Append(thisPath.Navigations[propIdx]); } } _cacheKey = keyBuilder.ToString(); } } } return _cacheKey; } ///null if both arguments are null/// Adds a path to span into the query. /// /// The path to span public void Include(string path) { EntityUtil.CheckStringArgument(path, "path"); SpanPath spanPath = new SpanPath(ParsePath(path)); AddSpanPath(spanPath); _cacheKey = null; } ////// Creates a new Span with the same SpanPaths as this Span /// ///internal Span Clone() { Span newSpan = new Span(); newSpan.SpanList.AddRange(_spanList); newSpan._cacheKey = this._cacheKey; return newSpan; } /// /// Adds the path if it does not already exist /// /// internal void AddSpanPath(SpanPath spanPath) { if (ValidateSpanPath(spanPath)) { RemoveExistingSubPaths(spanPath); _spanList.Add(spanPath); } } ////// Returns true if the path can be added /// /// private bool ValidateSpanPath(SpanPath spanPath) { // Check for dupliacte entries for (int i = 0; i < _spanList.Count; i++) { // make sure spanPath is not a sub-path of anything already in the list if (spanPath.IsSubPath(_spanList[i])) { return false; } } return true; } private void RemoveExistingSubPaths(SpanPath spanPath) { ListtoDelete = new List (); for (int i = 0; i < _spanList.Count; i++) { // make sure spanPath is not a sub-path of anything already in the list if (_spanList[i].IsSubPath(spanPath)) { toDelete.Add(_spanList[i]); } } foreach (SpanPath path in toDelete) { _spanList.Remove(path); } } /// /// Storage for a span path /// Currently this includes the list of navigation properties /// internal class SpanPath { public readonly ListNavigations; public SpanPath(List navigations) { Navigations = navigations; } public bool IsSubPath(SpanPath rhs) { // this is a subpath of rhs if it has fewer paths, and all the path element values are equal if (Navigations.Count > rhs.Navigations.Count) { return false; } for (int i = 0; i < Navigations.Count; i++) { if (!Navigations[i].Equals(rhs.Navigations[i], StringComparison.OrdinalIgnoreCase)) { return false; } } return true; } } private static List ParsePath(string path) { List navigations = new List (); string[] parts = System.Data.Common.MultipartIdentifier.ParseMultipartIdentifier(path, "[", "]", '.', 8, true, "Include", false); for (int i = parts.Length - 1; i >= 0; i--) { if (parts[i] != null) { if (parts[i].Length == 0) { throw EntityUtil.SpanPathSyntaxError(); } navigations.Add(parts[i]); } } Debug.Assert(navigations.Count > 0, "Empty path found"); if(navigations.Count > 1) { navigations.Reverse(); } return navigations; } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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