mcs/class/referencesource/System.Data/System/Data/Sql/SqlDataSourceEnumerator.cs

   1 //------------------------------------------------------------------------------
   2 // <copyright file="SqlDataSourceEnumerator.cs" company="Microsoft">
   3 //     Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 // <owner current="true" primary="true">Microsoft</owner>
   6 // <owner current="true" primary="false">Microsoft</owner>
   7 //------------------------------------------------------------------------------
   8
   9 namespace System.Data.Sql {
  10
  11     using System;
  12     using System.Data;
  13     using System.Data.Common;
  14     using System.Data.SqlClient;
  15     using System.Diagnostics;
  16     using System.Globalization;
  17     using System.Runtime.CompilerServices;
  18     using System.Runtime.InteropServices;
  19     using System.Security;
  20     using System.Text;
  21
  22     public sealed class SqlDataSourceEnumerator : DbDataSourceEnumerator {
  23
  24         private static readonly SqlDataSourceEnumerator SingletonInstance = new SqlDataSourceEnumerator();
  25         internal const string ServerName     = "ServerName";
  26         internal const string InstanceName   = "InstanceName";
  27         internal const string IsClustered    = "IsClustered";
  28         internal const string Version        = "Version";
  29 #if !MONO
  30         private  const int    timeoutSeconds = ADP.DefaultCommandTimeout;
  31 #endif
  32         private long timeoutTime;                                // variable used for timeout computations, holds the value of the hi-res performance counter at which this request should expire
  33
  34         private SqlDataSourceEnumerator() : base() {
  35         }
  36
  37         public static SqlDataSourceEnumerator Instance {
  38             get {
  39                 return SqlDataSourceEnumerator.SingletonInstance;
  40             }
  41         }
  42
  43         override public DataTable GetDataSources() {
  44 #if MONO
  45             timeoutTime = 0;
  46             throw new NotImplementedException ();
  47 #else
  48             (new NamedPermissionSet("FullTrust")).Demand(); // SQLBUDT 244304
  49             char[] buffer = null;
  50             StringBuilder strbldr = new StringBuilder();
  51
  52             Int32  bufferSize = 1024;
  53             Int32  readLength = 0;
  54             buffer            = new char[bufferSize];
  55                         bool   more       = true;
  56             bool   failure    = false;
  57             IntPtr handle     = ADP.PtrZero;
  58
  59                         RuntimeHelpers.PrepareConstrainedRegions();
  60             try {
  61                 timeoutTime = TdsParserStaticMethods.GetTimeoutSeconds(timeoutSeconds);
  62                 RuntimeHelpers.PrepareConstrainedRegions();
  63                 try {} finally {
  64                     handle = SNINativeMethodWrapper.SNIServerEnumOpen();
  65                 }
  66
  67                 if (ADP.PtrZero != handle) {
  68                     while (more && !TdsParserStaticMethods.TimeoutHasExpired(timeoutTime)) {
  69                                     readLength = SNINativeMethodWrapper.SNIServerEnumRead(handle, buffer, bufferSize, ref more);
  70                         if (readLength > bufferSize) {
  71                             failure = true;
  72                             more = false;
  73                         }
  74                         else if (0 < readLength) {
  75                                                         strbldr.Append(buffer, 0, readLength);
  76                                                 }
  77                     }
  78                 }
  79             }
  80             finally {
  81                 if (ADP.PtrZero != handle) {
  82                     SNINativeMethodWrapper.SNIServerEnumClose(handle);
  83                 }
  84             }
  85
  86             if (failure) {
  87                 Debug.Assert(false, "GetDataSources:SNIServerEnumRead returned bad length");
  88                 Bid.Trace("<sc.SqlDataSourceEnumerator.GetDataSources|ERR> GetDataSources:SNIServerEnumRead returned bad length, requested %d, received %d", bufferSize, readLength);
  89                 throw ADP.ArgumentOutOfRange("readLength");
  90             }
  91
  92             return ParseServerEnumString(strbldr.ToString());
  93 #endif
  94         }
  95
  96         private static string _Version = "Version:";
  97         private static string _Cluster = "Clustered:";
  98         private static int _clusterLength = _Cluster.Length;
  99         private static int _versionLength =_Version.Length;
 100
 101         static private DataTable ParseServerEnumString(string serverInstances) {
 102             DataTable dataTable = new DataTable("SqlDataSources");
 103             dataTable.Locale = CultureInfo.InvariantCulture;
 104             dataTable.Columns.Add(ServerName, typeof(string));
 105             dataTable.Columns.Add(InstanceName, typeof(string));
 106             dataTable.Columns.Add(IsClustered, typeof(string));
 107             dataTable.Columns.Add(Version, typeof(string));
 108             DataRow dataRow = null;
 109             string serverName = null;
 110             string instanceName = null;
 111             string isClustered = null;
 112             string version = null;
 113
 114             // Every row comes in the format "serverName\instanceName;Clustered:[Yes|No];Version:.."
 115             // Every row is terminated by a null character.
 116             // Process one row at a time
 117             foreach (string instance in serverInstances.Split('\0')) {
 118                 string value = instance.Trim('\0'); // MDAC 91934
 119                 if (0 == value.Length) {
 120                     continue;
 121                 }
 122                                 foreach (string instance2 in value.Split(';')) {
 123                                         if (serverName == null) {
 124                         foreach(string instance3 in instance2.Split('\\')) {
 125                                                         if (serverName == null) {
 126                                 serverName = instance3;
 127                                 continue;
 128                             }
 129                             Debug.Assert(instanceName == null);
 130                             instanceName = instance3;
 131                         }
 132                         continue;
 133                     }
 134                     if (isClustered == null) {
 135                         Debug.Assert(String.Compare(_Cluster, 0, instance2, 0, _clusterLength, StringComparison.OrdinalIgnoreCase) == 0);
 136                         isClustered = instance2.Substring(_clusterLength);
 137                         continue;
 138                     }
 139                     Debug.Assert(version == null);
 140                     Debug.Assert(String.Compare(_Version, 0, instance2, 0, _versionLength, StringComparison.OrdinalIgnoreCase) == 0);
 141                     version =  instance2.Substring(_versionLength);
 142                 }
 143
 144                 string query = "ServerName='"+serverName+"'";
 145
 146                 if (!ADP.IsEmpty(instanceName)) { // SQL BU DT 20006584: only append instanceName if present.
 147                     query += " AND InstanceName='"+instanceName+"'";
 148                 }
 149
 150                 // SNI returns dupes - do not add them.  SQL BU DT 290323
 151                 if (dataTable.Select(query).Length == 0) {
 152                     dataRow = dataTable.NewRow();
 153                     dataRow[0] = serverName;
 154                     dataRow[1] = instanceName;
 155                     dataRow[2] = isClustered;
 156                     dataRow[3] = version;
 157                     dataTable.Rows.Add(dataRow);
 158                 }
 159                 serverName = null;
 160                 instanceName = null;
 161                 isClustered = null;
 162                 version = null;
 163             }
 164             foreach(DataColumn column in dataTable.Columns) {
 165                 column.ReadOnly = true;
 166             }
 167             return dataTable;
 168         }
 169     }
 170 }