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using System; using System.Collections.Generic; using System.Diagnostics; using System.Text; namespace Npgsql; sealed class SqlQueryParser { static NpgsqlParameterCollection EmptyParameters { get; } = new(); readonly Dictionary _paramIndexMap = new(StringComparer.OrdinalIgnoreCase); readonly StringBuilder _rewrittenSql = new(); ///

///

/// Receives a user SQL query as passed in by the user in or /// , and rewrites it for PostgreSQL compatibility. ///

///

/// This includes doing rewriting named parameter placeholders to positional (@p => $1), and splitting the query /// up by semicolons (legacy batching, SELECT 1; SELECT 2). ///

///

/// Receives a user SQL query as passed in by the user in or /// , and rewrites it for PostgreSQL compatibility. ///

///

/// This includes doing rewriting named parameter placeholders to positional (@p => $1), and splitting the query /// up by semicolons (legacy batching, SELECT 1; SELECT 2). ///

///

/// The user-facing being executed. /// Whether PostgreSQL standards-conforming are used. /// /// A bool indicating whether parameters contains a list of preconfigured parameters or an empty list to be filled with derived /// parameters. /// internal void ParseRawQuery( NpgsqlBatchCommand? batchCommand, bool standardConformingStrings = true, bool deriveParameters = false) => ParseRawQuery(command: null, batchCommand, standardConformingStrings, deriveParameters); void ParseRawQuery( NpgsqlCommand? command, NpgsqlBatchCommand? batchCommand, bool standardConformingStrings = true, bool deriveParameters = false) { string sql; NpgsqlParameterCollection parameters; List? batchCommands; var statementIndex = 0; if (command is null) { // Batching mode. We're processing only one batch - if we encounter a semicolon (legacy batching), that's an error. Debug.Assert(batchCommand is not null); sql = batchCommand.CommandText; parameters = batchCommand._parameters ?? EmptyParameters; batchCommands = null; } else { // Command mode. Semicolons (legacy batching) may occur. Debug.Assert(batchCommand is null); sql = command.CommandText; parameters = command._parameters ?? EmptyParameters; batchCommands = command.InternalBatchCommands; MoveToNextBatchCommand(); } Debug.Assert(batchCommand is not null); Debug.Assert(parameters.PlaceholderType != PlaceholderType.Positional); Debug.Assert(deriveParameters == false || parameters.Count == 0); // Debug.Assert(batchCommand.PositionalParameters is not null && batchCommand.PositionalParameters.Count == 0); _paramIndexMap.Clear(); _rewrittenSql.Clear(); var currCharOfs = 0; var end = sql.Length; var ch = '\0'; int dollarTagStart; int dollarTagEnd; var currTokenBeg = 0; var blockCommentLevel = 0; var parenthesisLevel = 0; None: if (currCharOfs >= end) goto Finish; var lastChar = ch; ch = sql[currCharOfs++]; NoneContinue: while (true) { switch (ch) { case '/': goto BlockCommentBegin; case '-': goto LineCommentBegin; case '\'': if (standardConformingStrings) goto Quoted; goto Escaped; case '$': if (!IsIdentifier(lastChar)) goto DollarQuotedStart; break; case '"': goto Quoted; case ':': if (lastChar != ':') goto NamedParamStart; break; case '@': if (lastChar != '@') goto NamedParamStart; break; case ';': if (parenthesisLevel == 0) goto SemiColon; break; case '(': parenthesisLevel++; break; case ')': parenthesisLevel--; break; case 'e': case 'E': if (!IsLetter(lastChar)) goto EscapedStart; break; } if (currCharOfs >= end) goto Finish; lastChar = ch; ch = sql[currCharOfs++]; } NamedParamStart: if (currCharOfs < end) { lastChar = ch; ch = sql[currCharOfs]; if (IsParamNameChar(ch)) { if (currCharOfs - 1 > currTokenBeg) _rewrittenSql.Append(sql, currTokenBeg, currCharOfs - 1 - currTokenBeg); currTokenBeg = currCharOfs++ - 1; goto NamedParam; } currCharOfs++; goto NoneContinue; } goto Finish; NamedParam: // We have already at least one character of the param name while (true) { lastChar = ch; if (currCharOfs >= end || !IsParamNameChar(ch = sql[currCharOfs])) { var paramName = sql.Substring(currTokenBeg + 1, currCharOfs - (currTokenBeg + 1)); if (!_paramIndexMap.TryGetValue(paramName, out var index)) { // Parameter hasn't been seen before in this query if (!parameters.TryGetValue(paramName, out var parameter)) { if (deriveParameters) { parameter = new NpgsqlParameter { ParameterName = paramName }; parameters.Add(parameter); } else { // Parameter placeholder does not match a parameter on this command. // Leave the text as it was in the SQL, it may not be a an actual placeholder _rewrittenSql.Append(sql, currTokenBeg, currCharOfs - currTokenBeg); currTokenBeg = currCharOfs; if (currCharOfs >= end) goto Finish; currCharOfs++; goto NoneContinue; } } if (!parameter.IsInputDirection) ThrowHelper.ThrowInvalidOperationException("Parameter '{0}' referenced in SQL but is an out-only parameter", paramName); batchCommand.PositionalParameters.Add(parameter); index = _paramIndexMap[paramName] = batchCommand.PositionalParameters.Count; } _rewrittenSql.Append('$'); _rewrittenSql.Append(index); currTokenBeg = currCharOfs; if (currCharOfs >= end) goto Finish; currCharOfs++; goto NoneContinue; } currCharOfs++; } Quoted: Debug.Assert(ch == '\'' || ch == '"'); while (currCharOfs < end && sql[currCharOfs] != ch) { currCharOfs++; } if (currCharOfs < end) { currCharOfs++; ch = '\0'; goto None; } goto Finish; EscapedStart: if (currCharOfs < end) { lastChar = ch; ch = sql[currCharOfs++]; if (ch == '\'') goto Escaped; goto NoneContinue; } goto Finish; Escaped: while (currCharOfs < end) { ch = sql[currCharOfs++]; switch (ch) { case '\'': goto MaybeConcatenatedEscaped; case '\\': { if (currCharOfs >= end) goto Finish; currCharOfs++; break; } } } goto Finish; MaybeConcatenatedEscaped: while (currCharOfs < end) { ch = sql[currCharOfs++]; switch (ch) { case '\r': case '\n': goto MaybeConcatenatedEscaped2; case ' ': case '\t': case '\f': continue; default: lastChar = '\0'; goto NoneContinue; } } goto Finish; MaybeConcatenatedEscaped2: while (currCharOfs < end) { ch = sql[currCharOfs++]; switch (ch) { case '\'': goto Escaped; case '-': { if (currCharOfs >= end) goto Finish; ch = sql[currCharOfs++]; if (ch == '-') goto MaybeConcatenatedEscapeAfterComment; lastChar = '\0'; goto NoneContinue; } case ' ': case '\t': case '\n': case '\r': case '\f': continue; default: lastChar = '\0'; goto NoneContinue; } } goto Finish; MaybeConcatenatedEscapeAfterComment: while (currCharOfs < end) { ch = sql[currCharOfs++]; if (ch == '\r' || ch == '\n') goto MaybeConcatenatedEscaped2; } goto Finish; DollarQuotedStart: if (currCharOfs < end) { ch = sql[currCharOfs]; if (ch == '$') { // Empty tag dollarTagStart = dollarTagEnd = currCharOfs; currCharOfs++; goto DollarQuoted; } if (IsIdentifierStart(ch)) { dollarTagStart = currCharOfs; currCharOfs++; goto DollarQuotedInFirstDelim; } lastChar = '$'; currCharOfs++; goto NoneContinue; } goto Finish; DollarQuotedInFirstDelim: while (currCharOfs < end) { lastChar = ch; ch = sql[currCharOfs++]; if (ch == '$') { dollarTagEnd = currCharOfs - 1; goto DollarQuoted; } if (!IsDollarTagIdentifier(ch)) goto NoneContinue; } goto Finish; DollarQuoted: var tag = sql.AsSpan(dollarTagStart - 1, dollarTagEnd - dollarTagStart + 2); var pos = sql.AsSpan(dollarTagEnd + 1).IndexOf(tag); if (pos == -1) { currCharOfs = end; goto Finish; } pos += dollarTagEnd + 1; // If the substring is found adjust the position to be relative to the entire string currCharOfs = pos + dollarTagEnd - dollarTagStart + 2; ch = '\0'; goto None; LineCommentBegin: if (currCharOfs < end) { ch = sql[currCharOfs++]; if (ch == '-') goto LineComment; lastChar = '\0'; goto NoneContinue; } goto Finish; LineComment: while (currCharOfs < end) { ch = sql[currCharOfs++]; if (ch == '\r' || ch == '\n') goto None; } goto Finish; BlockCommentBegin: while (currCharOfs < end) { ch = sql[currCharOfs++]; if (ch == '*') { blockCommentLevel++; goto BlockComment; } if (ch != '/') { if (blockCommentLevel > 0) goto BlockComment; lastChar = '\0'; goto NoneContinue; } } goto Finish; BlockComment: while (currCharOfs < end) { ch = sql[currCharOfs++]; switch (ch) { case '*': goto BlockCommentEnd; case '/': goto BlockCommentBegin; } } goto Finish; BlockCommentEnd: while (currCharOfs < end) { ch = sql[currCharOfs++]; if (ch == '/') { if (--blockCommentLevel > 0) goto BlockComment; goto None; } if (ch != '*') goto BlockComment; } goto Finish; SemiColon: _rewrittenSql.Append(sql, currTokenBeg, currCharOfs - currTokenBeg - 1); batchCommand.FinalCommandText = _rewrittenSql.ToString(); while (currCharOfs < end) { ch = sql[currCharOfs]; if (char.IsWhiteSpace(ch)) { currCharOfs++; continue; } // TODO: Handle end of line comment? Although psql doesn't seem to handle them... // We've found a non-whitespace character after a semicolon - this is legacy batching. if (command is null) { ThrowHelper.ThrowNotSupportedException($"Specifying multiple SQL statements in a single {nameof(NpgsqlBatchCommand)} isn't supported, " + "please remove all semicolons."); } statementIndex++; MoveToNextBatchCommand(); _paramIndexMap.Clear(); _rewrittenSql.Clear(); currTokenBeg = currCharOfs; goto None; } if (batchCommands is not null && batchCommands.Count > statementIndex + 1) batchCommands.RemoveRange(statementIndex + 1, batchCommands.Count - (statementIndex + 1)); return; Finish: _rewrittenSql.Append(sql, currTokenBeg, end - currTokenBeg); if (statementIndex is 0 && _paramIndexMap.Count is 0) // Single statement, no parameters, no rewriting necessary batchCommand.FinalCommandText = sql; else batchCommand.FinalCommandText = _rewrittenSql.ToString(); if (batchCommands is not null && batchCommands.Count > statementIndex + 1) batchCommands.RemoveRange(statementIndex + 1, batchCommands.Count - (statementIndex + 1)); void MoveToNextBatchCommand() { Debug.Assert(batchCommands is not null); if (batchCommands.Count > statementIndex) { batchCommand = batchCommands[statementIndex]; batchCommand.Reset(); } else { batchCommand = new NpgsqlBatchCommand(); batchCommands.Add(batchCommand); } } } // Is ASCII letter comparison optimization https://github.com/dotnet/runtime/blob/60cfaec2e6cffeb9a006bec4b8908ffcf71ac5b4/src/libraries/System.Private.CoreLib/src/System/Char.cs#L236 static bool IsLetter(char ch) // [a-zA-Z] => (uint)((ch | 0x20) - 'a') <= ('z' - 'a'); static bool IsIdentifierStart(char ch) // [a-zA-Z_\x80-\xFF] => (uint)((ch | 0x20) - 'a') <= ('z' - 'a') || ch == '_' || (uint)(ch - 128) <= 127u; static bool IsDollarTagIdentifier(char ch) // [a-zA-Z0-9_\x80-\xFF] => (uint)((ch | 0x20) - 'a') <= ('z' - 'a') || (uint)(ch - '0') <= ('9' - '0') || ch == '_' || (uint)(ch - 128) <= 127u; static bool IsIdentifier(char ch) // [a-zA-Z0-9_$\x80-\xFF] => (uint)((ch | 0x20) - 'a') <= ('z' - 'a') || (uint)(ch - '0') <= ('9' - '0') || ch == '_' || ch == '$' || (uint)(ch - 128) <= 127u; static bool IsParamNameChar(char ch) => char.IsLetterOrDigit(ch) || ch == '_' || ch == '.'; // why dot?? }

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