Code:
/ DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / Designer / WebForms / System / Web / UI / Design / WebControls / SqlDataSourceCommandParser.cs / 1 / SqlDataSourceCommandParser.cs
//------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //----------------------------------------------------------------------------- namespace System.Web.UI.Design.WebControls { using System; using System.Collections; using System.Diagnostics; using System.Globalization; using System.Text; using System.Web.UI.WebControls; // ////// Helper class for parsing simple SQL SELECT commands to extract the /// list of selected fields and which table they are being selected /// from. This it not a complete parser, it only handles limited scenarios. /// internal static class SqlDataSourceCommandParser { private static bool ConsumeField(string s, int startIndex, System.Collections.Generic.Listparts) { // Skip whitespace while ((startIndex < s.Length) && (Char.IsWhiteSpace(s, startIndex))) { startIndex++; } string fieldName; startIndex = ConsumeIdentifier(s, startIndex, out fieldName); parts.Add(fieldName); return ExpectField(s, startIndex, parts); } private static bool ConsumeFrom(string s, int startIndex, System.Collections.Generic.List parts) { // Skip whitespace while ((startIndex < s.Length) && (Char.IsWhiteSpace(s, startIndex))) { startIndex++; } // If we're at the end of the string, abort if (startIndex + 5 >= s.Length) { return false; } if (String.Compare(s, startIndex, "from", 0, 4, StringComparison.OrdinalIgnoreCase) == 0) { if (Char.IsWhiteSpace(s, startIndex + 4)) { return ConsumeTable(s, startIndex + 5, parts); } } return false; } private static int ConsumeIdentifier(string s, int startIndex, out string identifier) { bool inBracket = false; identifier = String.Empty; // while (startIndex < s.Length) { if ((!inBracket) && (s[startIndex] == '[')) { inBracket = true; identifier += s[startIndex]; startIndex++; } else { if (inBracket && (s[startIndex] == ']')) { inBracket = false; identifier += s[startIndex]; startIndex++; } else { if (inBracket) { // In a bracket we'll take anything identifier += s[startIndex]; startIndex++; } else { // Not in a bracket, we'll only take certain chars if ((!Char.IsWhiteSpace(s, startIndex)) && (s[startIndex] != ',')) { identifier += s[startIndex]; startIndex++; } else { break; } } } } } return startIndex; } private static bool ConsumeSelect(string s, int startIndex, System.Collections.Generic.List parts) { if (s.Length < 7) { return false; } if (!s.ToLowerInvariant().StartsWith("select", StringComparison.Ordinal)) { return false; } if (!Char.IsWhiteSpace(s, 6)) { return false; } return ConsumeField(s, startIndex + 7, parts); } private static bool ConsumeTable(string s, int startIndex, System.Collections.Generic.List parts) { // Skip whitespace while ((startIndex < s.Length) && (Char.IsWhiteSpace(s, startIndex))) { startIndex++; } string fieldName; startIndex = ConsumeIdentifier(s, startIndex, out fieldName); parts.Add(fieldName); // Make sure there is nothing after this if (startIndex == s.Length) { return true; } else { return false; } } private static bool ExpectField(string s, int startIndex, System.Collections.Generic.List parts) { // Skip whitespace while ((startIndex < s.Length) && (Char.IsWhiteSpace(s, startIndex))) { startIndex++; } // If we're at the end of the string, abort if (startIndex >= s.Length - 1) { return false; } if (s[startIndex] == ',') { // A comma indicates there are more fields coming return ConsumeField(s, startIndex + 1, parts); } else { // No comma, we are done with fields return ConsumeFrom(s, startIndex, parts); } } /// /// Splits a SQL identifier such as [db].[user].[object] into its parts: /// db, user, object /// private static string[] GetIdentifierParts(string identifier) { Debug.Assert(identifier != null); bool inBrackets = false; StringBuilder sb = new StringBuilder(); ArrayList result = new ArrayList(); for (int i = 0; i < identifier.Length; i++) { char c = identifier[i]; switch (c) { case '[': if (inBrackets) { Debug.Fail(String.Format(CultureInfo.InvariantCulture, "The identifier {0} contains invalid characters", identifier)); return null; } inBrackets = true; break; case ']': if ((inBrackets == false) || (identifier.Length > i + 2) && (identifier[i + 1] != '.')) { Debug.Fail(String.Format(CultureInfo.InvariantCulture, "The identifier {0} contains invalid characters", identifier)); return null; } inBrackets = false; break; case '.': if (inBrackets) { sb.Append('.'); } else { result.Add(sb.ToString()); sb.Length = 0; } break; default: if (inBrackets == false) { switch (c) { case '@': case '#': case '_': case '*': // This allows [foo].* to work break; default: if (Char.IsLetter(c)) { break; } // First char can't be $ or digit if ((sb.Length > 0) && ((c == '$') || Char.IsDigit(c))) { break; } Debug.Fail(String.Format(CultureInfo.InvariantCulture, "The identifier {0} contains invalid characters", identifier)); return null; } } sb.Append(c); break; } } result.Add(sb.ToString()); return (string[])result.ToArray(typeof(string)); } ////// Parses an identifier such as [foo].[bar] and returns just the /// "bar" part. /// public static string GetLastIdentifierPart(string identifier) { string[] parts = GetIdentifierParts(identifier); if ((parts == null) || (parts.Length == 0)) { return null; } else { return parts[parts.Length - 1]; } } ////// Parses a simple SQL command string and extracts the list of /// selected fields and the table name. The return value is null if /// there was any problem parsing the string. The last field returned /// is really the name of the table being selected from, not a field. /// public static string[] ParseSqlString(string sqlString) { if (String.IsNullOrEmpty(sqlString)) { return null; } try { sqlString = sqlString.Trim(); System.Collections.Generic.Listparts = new System.Collections.Generic.List (); bool success = ConsumeSelect(sqlString, 0, parts); return (success ? parts.ToArray() : null); } catch (Exception ex) { Debug.Fail("Caught an exception in SqlParser: " + ex.Message); return null; } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved.
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