/*
* Copyright 1999-2012 Alibaba Group.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.alibaba.cobar.server.parser;
import com.alibaba.cobar.parser.util.CharTypes;
import com.alibaba.cobar.parser.util.ParseUtil;
/**
* @author xianmao.hexm 2011-5-7 下午01:23:18
*/
public final class ServerParseSelect {
public static final int OTHER = -1;
public static final int VERSION_COMMENT = 1;
public static final int DATABASE = 2;
public static final int USER = 3;
public static final int LAST_INSERT_ID = 4;
public static final int IDENTITY = 5;
public static final int VERSION = 6;
private static final char[] _VERSION_COMMENT = "VERSION_COMMENT".toCharArray();
private static final char[] _IDENTITY = "IDENTITY".toCharArray();
private static final char[] _LAST_INSERT_ID = "LAST_INSERT_ID".toCharArray();
private static final char[] _DATABASE = "DATABASE()".toCharArray();
public static int parse(String stmt, int offset) {
int i = offset;
for (; i < stmt.length(); ++i) {
switch (stmt.charAt(i)) {
case ' ':
continue;
case '/':
case '#':
i = ParseUtil.comment(stmt, i);
continue;
case '@':
return select2Check(stmt, i);
case 'D':
case 'd':
return databaseCheck(stmt, i);
case 'L':
case 'l':
return lastInsertCheck(stmt, i);
case 'U':
case 'u':
return userCheck(stmt, i);
case 'V':
case 'v':
return versionCheck(stmt, i);
default:
return OTHER;
}
}
return OTHER;
}
// SELECT VERSION
private static int versionCheck(String stmt, int offset) {
if (stmt.length() > offset + "ERSION".length()) {
char c1 = stmt.charAt(++offset);
char c2 = stmt.charAt(++offset);
char c3 = stmt.charAt(++offset);
char c4 = stmt.charAt(++offset);
char c5 = stmt.charAt(++offset);
char c6 = stmt.charAt(++offset);
if ((c1 == 'E' || c1 == 'e') && (c2 == 'R' || c2 == 'r') && (c3 == 'S' || c3 == 's')
&& (c4 == 'I' || c4 == 'i') && (c5 == 'O' || c5 == 'o') && (c6 == 'N' || c6 == 'n')) {
while (stmt.length() > ++offset) {
switch (stmt.charAt(offset)) {
case ' ':
case '\t':
case '\r':
case '\n':
continue;
case '(':
return versionParenthesisCheck(stmt, offset);
default:
return OTHER;
}
}
}
}
return OTHER;
}
// SELECT VERSION (
private static int versionParenthesisCheck(String stmt, int offset) {
while (stmt.length() > ++offset) {
switch (stmt.charAt(offset)) {
case ' ':
case '\t':
case '\r':
case '\n':
continue;
case ')':
while (stmt.length() > ++offset) {
switch (stmt.charAt(offset)) {
case ' ':
case '\t':
case '\r':
case '\n':
continue;
default:
return OTHER;
}
}
return VERSION;
default:
return OTHER;
}
}
return OTHER;
}
/**
* <code>SELECT LAST_INSERT_ID() AS id, </code>
*
* @param offset index of 'i', offset == stmt.length() is possible
* @return index of ','. return stmt.length() is possible. -1 if not alias
*/
private static int skipAlias(String stmt, int offset) {
offset = ParseUtil.move(stmt, offset, 0);
if (offset >= stmt.length())
return offset;
switch (stmt.charAt(offset)) {
case '\'':
return skipString(stmt, offset);
case '"':
return skipString2(stmt, offset);
case '`':
return skipIdentifierEscape(stmt, offset);
default:
if (CharTypes.isIdentifierChar(stmt.charAt(offset))) {
for (; offset < stmt.length() && CharTypes.isIdentifierChar(stmt.charAt(offset)); ++offset);
return offset;
}
}
return -1;
}
/**
* <code>`abc`d</code>
*
* @param offset index of first <code>`</code>
* @return index of 'd'. return stmt.length() is possible. -1 if string
* invalid
*/
private static int skipIdentifierEscape(String stmt, int offset) {
for (++offset; offset < stmt.length(); ++offset) {
if (stmt.charAt(offset) == '`') {
if (++offset >= stmt.length() || stmt.charAt(offset) != '`') {
return offset;
}
}
}
return -1;
}
/**
* <code>"abc"d</code>
*
* @param offset index of first <code>"</code>
* @return index of 'd'. return stmt.length() is possible. -1 if string
* invalid
*/
private static int skipString2(String stmt, int offset) {
int state = 0;
for (++offset; offset < stmt.length(); ++offset) {
char c = stmt.charAt(offset);
switch (state) {
case 0:
switch (c) {
case '\\':
state = 1;
break;
case '"':
state = 2;
break;
}
break;
case 1:
state = 0;
break;
case 2:
switch (c) {
case '"':
state = 0;
break;
default:
return offset;
}
break;
}
}
if (offset == stmt.length() && state == 2) {
return stmt.length();
}
return -1;
}
/**
* <code>'abc'd</code>
*
* @param offset index of first <code>'</code>
* @return index of 'd'. return stmt.length() is possible. -1 if string
* invalid
*/
private static int skipString(String stmt, int offset) {
int state = 0;
for (++offset; offset < stmt.length(); ++offset) {
char c = stmt.charAt(offset);
switch (state) {
case 0:
switch (c) {
case '\\':
state = 1;
break;
case '\'':
state = 2;
break;
}
break;
case 1:
state = 0;
break;
case 2:
switch (c) {
case '\'':
state = 0;
break;
default:
return offset;
}
break;
}
}
if (offset == stmt.length() && state == 2) {
return stmt.length();
}
return -1;
}
/**
* <code>SELECT LAST_INSERT_ID() AS id</code>
*
* @param offset index of first ' ' after LAST_INSERT_ID(), offset ==
* stmt.length() is possible
* @return index of 'i'. return stmt.length() is possible
*/
public static int skipAs(String stmt, int offset) {
offset = ParseUtil.move(stmt, offset, 0);
if (stmt.length() > offset + "AS".length()
&& (stmt.charAt(offset) == 'A' || stmt.charAt(offset) == 'a')
&& (stmt.charAt(offset + 1) == 'S' || stmt.charAt(offset + 1) == 's')
&& (stmt.charAt(offset + 2) == ' ' || stmt.charAt(offset + 2) == '\r'
|| stmt.charAt(offset + 2) == '\n' || stmt.charAt(offset + 2) == '\t'
|| stmt.charAt(offset + 2) == '/' || stmt.charAt(offset + 2) == '#')) {
offset = ParseUtil.move(stmt, offset + 2, 0);
}
return offset;
}
/**
* @param offset <code>stmt.charAt(offset) == first 'L' OR 'l'</code>
* @return index after LAST_INSERT_ID(), might equals to length. -1 if not
* LAST_INSERT_ID
*/
public static int indexAfterLastInsertIdFunc(String stmt, int offset) {
if (stmt.length() >= offset + "LAST_INSERT_ID()".length()) {
if (ParseUtil.compare(stmt, offset, _LAST_INSERT_ID)) {
offset = ParseUtil.move(stmt, offset + _LAST_INSERT_ID.length, 0);
if (offset + 1 < stmt.length() && stmt.charAt(offset) == '(') {
offset = ParseUtil.move(stmt, offset + 1, 0);
if (offset < stmt.length() && stmt.charAt(offset) == ')') {
return ++offset;
}
}
}
}
return -1;
}
/**
* @param offset
* <code>stmt.charAt(offset) == first '`' OR 'i' OR 'I' OR '\'' OR '"'</code>
* @return index after identity or `identity` or "identity" or 'identity',
* might equals to length. -1 if not identity or `identity` or
* "identity" or 'identity'
*/
public static int indexAfterIdentity(String stmt, int offset) {
char first = stmt.charAt(offset);
switch (first) {
case '`':
case '\'':
case '"':
if (stmt.length() < offset + "identity".length() + 2) {
return -1;
}
if (stmt.charAt(offset + "identity".length() + 1) != first) {
return -1;
}
++offset;
break;
case 'i':
case 'I':
if (stmt.length() < offset + "identity".length()) {
return -1;
}
break;
default:
return -1;
}
if (ParseUtil.compare(stmt, offset, _IDENTITY)) {
offset += _IDENTITY.length;
switch (first) {
case '`':
case '\'':
case '"':
return ++offset;
}
return offset;
}
return -1;
}
/**
* SELECT LAST_INSERT_ID()
*/
static int lastInsertCheck(String stmt, int offset) {
offset = indexAfterLastInsertIdFunc(stmt, offset);
if (offset < 0) {
return OTHER;
}
offset = skipAs(stmt, offset);
offset = skipAlias(stmt, offset);
if (offset < 0) {
return OTHER;
}
offset = ParseUtil.move(stmt, offset, 0);
if (offset < stmt.length()) {
return OTHER;
}
return LAST_INSERT_ID;
}
/**
* select @@identity<br/>
* select @@identiTy aS iD
*/
static int identityCheck(String stmt, int offset) {
offset = indexAfterIdentity(stmt, offset);
if (offset < 0) {
return OTHER;
}
offset = skipAs(stmt, offset);
offset = skipAlias(stmt, offset);
if (offset < 0) {
return OTHER;
}
offset = ParseUtil.move(stmt, offset, 0);
if (offset < stmt.length()) {
return OTHER;
}
return IDENTITY;
}
static int select2Check(String stmt, int offset) {
if (stmt.length() > ++offset && stmt.charAt(offset) == '@') {
if (stmt.length() > ++offset) {
switch (stmt.charAt(offset)) {
case 'V':
case 'v':
return versionCommentCheck(stmt, offset);
case 'i':
case 'I':
return identityCheck(stmt, offset);
default:
return OTHER;
}
}
}
return OTHER;
}
/**
* SELECT DATABASE()
*/
static int databaseCheck(String stmt, int offset) {
int length = offset + _DATABASE.length;
if (stmt.length() >= length && ParseUtil.compare(stmt, offset, _DATABASE)) {
if (stmt.length() > length && stmt.charAt(length) != ' ') {
return OTHER;
} else {
return DATABASE;
}
}
return OTHER;
}
/**
* SELECT USER()
*/
static int userCheck(String stmt, int offset) {
if (stmt.length() > offset + 5) {
char c1 = stmt.charAt(++offset);
char c2 = stmt.charAt(++offset);
char c3 = stmt.charAt(++offset);
char c4 = stmt.charAt(++offset);
char c5 = stmt.charAt(++offset);
if ((c1 == 'S' || c1 == 's') && (c2 == 'E' || c2 == 'e') && (c3 == 'R' || c3 == 'r') && (c4 == '(')
&& (c5 == ')') && (stmt.length() == ++offset || ParseUtil.isEOF(stmt.charAt(offset)))) {
return USER;
}
}
return OTHER;
}
/**
* SELECT @@VERSION_COMMENT
*/
static int versionCommentCheck(String stmt, int offset) {
int length = offset + _VERSION_COMMENT.length;
if (stmt.length() >= length && ParseUtil.compare(stmt, offset, _VERSION_COMMENT)) {
if (stmt.length() > length && stmt.charAt(length) != ' ') {
return OTHER;
} else {
return VERSION_COMMENT;
}
}
return OTHER;
}
}