import type { ConnectorType } from "../connectors/interface.js";
const TokenType = { Plain: 0, Comment: 1, QuotedBlock: 2 } as const;
interface SQLToken {
type: number;
/** Position just past the end of this token (the next unprocessed character) */
end: number;
}
function plainToken(i: number): SQLToken {
return { type: TokenType.Plain, end: i + 1 };
}
function scanSingleLineComment(sql: string, i: number): SQLToken | null {
if (sql[i] !== "-" || sql[i + 1] !== "-") { return null; }
let j = i;
while (j < sql.length && sql[j] !== "\n") { j++; }
return { type: TokenType.Comment, end: j };
}
function scanMultiLineComment(sql: string, i: number): SQLToken | null {
if (sql[i] !== "/" || sql[i + 1] !== "*") { return null; }
let j = i + 2;
while (j < sql.length && !(sql[j] === "*" && sql[j + 1] === "/")) { j++; }
if (j < sql.length) { j += 2; }
return { type: TokenType.Comment, end: j };
}
function scanNestedMultiLineComment(sql: string, i: number): SQLToken | null {
if (sql[i] !== "/" || sql[i + 1] !== "*") { return null; }
let j = i + 2;
let depth = 1;
while (j < sql.length && depth > 0) {
if (sql[j] === "/" && sql[j + 1] === "*") { depth++; j += 2; }
else if (sql[j] === "*" && sql[j + 1] === "/") { depth--; j += 2; }
else { j++; }
}
return { type: TokenType.Comment, end: j };
}
function scanSingleQuotedString(sql: string, i: number): SQLToken | null {
if (sql[i] !== "'") { return null; }
let j = i + 1;
while (j < sql.length) {
if (sql[j] === "'" && sql[j + 1] === "'") { j += 2; }
else if (sql[j] === "'") { j++; break; }
else { j++; }
}
return { type: TokenType.QuotedBlock, end: j };
}
function scanDoubleQuotedString(sql: string, i: number): SQLToken | null {
if (sql[i] !== '"') { return null; }
let j = i + 1;
while (j < sql.length) {
if (sql[j] === '"' && sql[j + 1] === '"') { j += 2; }
else if (sql[j] === '"') { j++; break; }
else { j++; }
}
return { type: TokenType.QuotedBlock, end: j };
}
// Matches $$ or $tag$ where tag is [a-zA-Z_]\w* (digits after $ do NOT start a tag, so $1 is safe)
const dollarQuoteOpenRegex = /^\$([a-zA-Z_]\w*)?\$/;
function scanDollarQuotedBlock(sql: string, i: number): SQLToken | null {
if (sql[i] !== "$") { return null; }
// $N where N is a digit is a positional parameter, not a dollar-quote
const next = sql[i + 1];
if (next >= "0" && next <= "9") { return null; }
const remaining = sql.substring(i);
const m = dollarQuoteOpenRegex.exec(remaining);
if (!m) { return null; }
const tag = m[0];
const bodyStart = i + tag.length;
const closeIdx = sql.indexOf(tag, bodyStart);
const end = closeIdx !== -1 ? closeIdx + tag.length : sql.length;
return { type: TokenType.QuotedBlock, end };
}
function scanBacktickQuotedIdentifier(sql: string, i: number): SQLToken | null {
if (sql[i] !== "`") { return null; }
let j = i + 1;
while (j < sql.length) {
if (sql[j] === "`" && sql[j + 1] === "`") { j += 2; }
else if (sql[j] === "`") { j++; break; }
else { j++; }
}
return { type: TokenType.QuotedBlock, end: j };
}
function scanBracketQuotedIdentifier(sql: string, i: number): SQLToken | null {
if (sql[i] !== "[") { return null; }
let j = i + 1;
while (j < sql.length) {
if (sql[j] === "]" && sql[j + 1] === "]") { j += 2; }
else if (sql[j] === "]") { j++; break; }
else { j++; }
}
return { type: TokenType.QuotedBlock, end: j };
}
function scanTokenAnsi(sql: string, i: number): SQLToken {
return scanSingleLineComment(sql, i)
?? scanMultiLineComment(sql, i)
?? scanSingleQuotedString(sql, i)
?? scanDoubleQuotedString(sql, i)
?? plainToken(i);
}
function scanTokenPostgres(sql: string, i: number): SQLToken {
return scanSingleLineComment(sql, i)
?? scanNestedMultiLineComment(sql, i)
?? scanSingleQuotedString(sql, i)
?? scanDoubleQuotedString(sql, i)
?? scanDollarQuotedBlock(sql, i)
?? plainToken(i);
}
function scanTokenMySQL(sql: string, i: number): SQLToken {
return scanSingleLineComment(sql, i)
?? scanMultiLineComment(sql, i)
?? scanSingleQuotedString(sql, i)
?? scanDoubleQuotedString(sql, i)
?? scanBacktickQuotedIdentifier(sql, i)
?? plainToken(i);
}
function scanTokenSQLite(sql: string, i: number): SQLToken {
return scanSingleLineComment(sql, i)
?? scanMultiLineComment(sql, i)
?? scanSingleQuotedString(sql, i)
?? scanDoubleQuotedString(sql, i)
?? scanBacktickQuotedIdentifier(sql, i)
?? scanBracketQuotedIdentifier(sql, i)
?? plainToken(i);
}
function scanTokenSQLServer(sql: string, i: number): SQLToken {
return scanSingleLineComment(sql, i)
?? scanMultiLineComment(sql, i)
?? scanSingleQuotedString(sql, i)
?? scanDoubleQuotedString(sql, i)
?? scanBracketQuotedIdentifier(sql, i)
?? plainToken(i);
}
type TokenScanner = (sql: string, i: number) => SQLToken;
const dialectScanners: Record<ConnectorType, TokenScanner> = {
postgres: scanTokenPostgres,
mysql: scanTokenMySQL,
mariadb: scanTokenMySQL,
sqlite: scanTokenSQLite,
sqlserver: scanTokenSQLServer,
};
function getScanner(dialect?: ConnectorType): TokenScanner {
return dialect ? (dialectScanners[dialect] ?? scanTokenAnsi) : scanTokenAnsi;
}
/**
* Replace comments, string literals, and dialect-specific quoted blocks with a single space each.
* When no dialect is specified, only ANSI SQL syntax is recognized.
*/
export function stripCommentsAndStrings(sql: string, dialect?: ConnectorType): string {
const scanToken = getScanner(dialect);
const parts: string[] = [];
let plainStart = -1;
let i = 0;
while (i < sql.length) {
const token = scanToken(sql, i);
if (token.type === TokenType.Plain) {
if (plainStart === -1) { plainStart = i; }
} else {
if (plainStart !== -1) {
parts.push(sql.substring(plainStart, i));
plainStart = -1;
}
parts.push(" ");
}
i = token.end;
}
if (plainStart !== -1) {
parts.push(sql.substring(plainStart));
}
return parts.join("");
}
/**
* Split SQL into individual statements, handling semicolons inside quoted contexts.
* When no dialect is specified, only ANSI SQL syntax is recognized.
*/
export function splitSQLStatements(sql: string, dialect?: ConnectorType): string[] {
const scanToken = getScanner(dialect);
const statements: string[] = [];
let stmtStart = 0;
let i = 0;
while (i < sql.length) {
if (sql[i] === ";") {
const trimmed = sql.substring(stmtStart, i).trim();
if (trimmed.length > 0) { statements.push(trimmed); }
stmtStart = i + 1;
i++;
continue;
}
const token = scanToken(sql, i);
i = token.end;
}
const trimmed = sql.substring(stmtStart).trim();
if (trimmed.length > 0) { statements.push(trimmed); }
return statements;
}
