// statement <- COLUMN COMPARE VALUE
// | COLUMN IS NULL
private static void parseStatement(Lexer lexer) {
// both possibilities start with COLUMN
if (lexer.currentToken() != Lexer.TOKEN_COLUMN) {
throw new IllegalArgumentException("syntax error, expected column name");
}
lexer.advance();
// statement <- COLUMN COMPARE VALUE
if (lexer.currentToken() == Lexer.TOKEN_COMPARE) {
lexer.advance();
if (lexer.currentToken() != Lexer.TOKEN_VALUE) {
throw new IllegalArgumentException("syntax error, expected quoted string");
}
lexer.advance();
return;
}
// statement <- COLUMN IS NULL
if (lexer.currentToken() == Lexer.TOKEN_IS) {
lexer.advance();
if (lexer.currentToken() != Lexer.TOKEN_NULL) {
throw new IllegalArgumentException("syntax error, expected NULL");
}
lexer.advance();
return;
}
// didn't get anything good after COLUMN
throw new IllegalArgumentException("syntax error after column name");
}
// expression <- ( expression ) | statement [AND_OR ( expression ) |
// statement] *
// | statement [AND_OR expression]*
private static void parseExpression(Lexer lexer) {
for (; ; ) {
// ( expression )
if (lexer.currentToken() == Lexer.TOKEN_OPEN_PAREN) {
lexer.advance();
parseExpression(lexer);
if (lexer.currentToken() != Lexer.TOKEN_CLOSE_PAREN) {
throw new IllegalArgumentException("syntax error, unmatched parenthese");
}
lexer.advance();
} else {
// statement
parseStatement(lexer);
}
if (lexer.currentToken() != Lexer.TOKEN_AND_OR) {
break;
}
lexer.advance();
}
}
/** Checks whether this looks like a legitimate selection parameter */
public static void validateSelection(String selection, Set<String> allowedColumns) {
try {
if (selection == null || selection.length() == 0) {
return;
}
Lexer lexer = new Lexer(selection, allowedColumns);
parseExpression(lexer);
if (lexer.currentToken() != Lexer.TOKEN_END) {
throw new IllegalArgumentException("syntax error");
}
} catch (RuntimeException ex) {
if (Constants.LOGV) {
Log.d(Constants.TAG, "invalid selection [" + selection + "] triggered " + ex);
} else if (Config.LOGD) {
Log.d(Constants.TAG, "invalid selection triggered " + ex);
}
throw ex;
}
}
