queryparse.c

适合于Unix/Linux下的一个持久数据库连接池

// Copyright (c) 1999-2001  David Muse
// See the file COPYING for more information

#include <config.h>

#include <sqlrconnection.h>

bool sqlrcursor_svr::queryIsNotSelect() {

	// scan the query, bypassing whitespace and comments.
	char	*ptr=skipWhitespaceAndComments(querybuffer);

	// if the query is a select but not a select into then return false,
	// otherwise return true
	if (!charstring::compareIgnoringCase(ptr,"select",6) && 
		charstring::compareIgnoringCase(ptr,"select into ",12)) {
		return false;
	}
	return true;
}

bool sqlrcursor_svr::queryIsCommitOrRollback() {

	// scan the query, bypassing whitespace and comments.
	char	*ptr=skipWhitespaceAndComments(querybuffer);

	// if the query is a commit or rollback, return true
	// otherwise return false
	return (!charstring::compareIgnoringCase(ptr,"commit",6) ||
			!charstring::compareIgnoringCase(ptr,"rollback",8));
}

char *sqlrcursor_svr::skipWhitespaceAndComments(const char *querybuffer) {
	// scan the query, bypassing whitespace and comments.
	char	*ptr=(char *)querybuffer;
	while (*ptr && 
		(*ptr==' ' || *ptr=='\n' || *ptr=='	' || *ptr=='-')) {

		// skip any comments
		if (*ptr=='-') {
			while (*ptr && *ptr!='\n') {
				ptr++;
			}
		}
		ptr++;
	}
	return ptr;
}

void sqlrcursor_svr::checkForTempTable(const char *query, uint32_t length) {

	char	*ptr=(char *)query;
	char	*endptr=(char *)query+length;

	// skip any leading comments
	if (!skipWhitespace(&ptr,endptr) || !skipComment(&ptr,endptr) ||
		!skipWhitespace(&ptr,endptr)) {
		return;
	}

	// see if the query matches the pattern for a temporary query that
	// creates a temporary table
	if (createtemp.match(ptr)) {
		ptr=createtemp.getSubstringEnd(0);
	} else {
		return;
	}

	// get the table name
	stringbuffer	tablename;
	while (ptr && *ptr && *ptr!=' ' &&
		*ptr!='\n' && *ptr!='	' && ptr<endptr) {
		tablename.append(*ptr);
		ptr++;
	}

	// append to list of temp tables
	conn->addSessionTempTableForDrop(tablename.getString());
}

bool sqlrcursor_svr::skipComment(char **ptr, const char *endptr) {
	while (*ptr<endptr && !charstring::compare(*ptr,"--",2)) {
		while (**ptr && **ptr!='\n') {
			(*ptr)++;
		}
	}
	return *ptr!=endptr;
}

bool sqlrcursor_svr::skipWhitespace(char **ptr, const char *endptr) {
	while ((**ptr==' ' || **ptr=='\n' || **ptr=='	') && *ptr<endptr) {
		(*ptr)++;
	}
	return *ptr!=endptr;
}

bool sqlrcursor_svr::advance(char **ptr, const char *endptr, uint16_t steps) {
	for (uint16_t i=0; i<steps && *ptr<endptr; i++) {
		(*ptr)++;
	}
	return *ptr!=endptr;
}