src.android.database.sqlite.SQLiteTokenizer Maven / Gradle / Ivy
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/*
* Copyright (C) 2019 The Android Open Source Project
*
* 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 android.database.sqlite;
import android.annotation.NonNull;
import android.annotation.Nullable;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import java.util.function.Consumer;
/**
* SQL Tokenizer specialized to extract tokens from SQL (snippets).
*
* Based on sqlite3GetToken() in tokenzie.c in SQLite.
*
* Source for v3.8.6 (which android uses): http://www.sqlite.org/src/artifact/ae45399d6252b4d7
* (Latest source as of now: http://www.sqlite.org/src/artifact/78c8085bc7af1922)
*
* Also draft spec: http://www.sqlite.org/draft/tokenreq.html
*
* @hide
*/
public class SQLiteTokenizer {
private static boolean isAlpha(char ch) {
return ('a' <= ch && ch <= 'z') || ('A' <= ch && ch <= 'Z') || (ch == '_');
}
private static boolean isNum(char ch) {
return ('0' <= ch && ch <= '9');
}
private static boolean isAlNum(char ch) {
return isAlpha(ch) || isNum(ch);
}
private static boolean isAnyOf(char ch, String set) {
return set.indexOf(ch) >= 0;
}
private static IllegalArgumentException genException(String message, String sql) {
throw new IllegalArgumentException(message + " in '" + sql + "'");
}
private static char peek(String s, int index) {
return index < s.length() ? s.charAt(index) : '\0';
}
public static final int OPTION_NONE = 0;
/**
* Require that SQL contains only tokens; any comments or values will result
* in an exception.
*/
public static final int OPTION_TOKEN_ONLY = 1 << 0;
/**
* Tokenize the given SQL, returning the list of each encountered token.
*
* @throws IllegalArgumentException if invalid SQL is encountered.
*/
public static List tokenize(@Nullable String sql, int options) {
final ArrayList res = new ArrayList<>();
tokenize(sql, options, res::add);
return res;
}
/**
* Tokenize the given SQL, sending each encountered token to the given
* {@link Consumer}.
*
* @throws IllegalArgumentException if invalid SQL is encountered.
*/
public static void tokenize(@Nullable String sql, int options, Consumer checker) {
if (sql == null) {
return;
}
int pos = 0;
final int len = sql.length();
while (pos < len) {
final char ch = peek(sql, pos);
// Regular token.
if (isAlpha(ch)) {
final int start = pos;
pos++;
while (isAlNum(peek(sql, pos))) {
pos++;
}
final int end = pos;
final String token = sql.substring(start, end);
checker.accept(token);
continue;
}
// Handle quoted tokens
if (isAnyOf(ch, "'\"`")) {
final int quoteStart = pos;
pos++;
for (;;) {
pos = sql.indexOf(ch, pos);
if (pos < 0) {
throw genException("Unterminated quote", sql);
}
if (peek(sql, pos + 1) != ch) {
break;
}
// Quoted quote char -- e.g. "abc""def" is a single string.
pos += 2;
}
final int quoteEnd = pos;
pos++;
if (ch != '\'') {
// Extract the token
final String tokenUnquoted = sql.substring(quoteStart + 1, quoteEnd);
final String token;
// Unquote if needed. i.e. "aa""bb" -> aa"bb
if (tokenUnquoted.indexOf(ch) >= 0) {
token = tokenUnquoted.replaceAll(
String.valueOf(ch) + ch, String.valueOf(ch));
} else {
token = tokenUnquoted;
}
checker.accept(token);
} else {
if ((options &= OPTION_TOKEN_ONLY) != 0) {
throw genException("Non-token detected", sql);
}
}
continue;
}
// Handle tokens enclosed in [...]
if (ch == '[') {
final int quoteStart = pos;
pos++;
pos = sql.indexOf(']', pos);
if (pos < 0) {
throw genException("Unterminated quote", sql);
}
final int quoteEnd = pos;
pos++;
final String token = sql.substring(quoteStart + 1, quoteEnd);
checker.accept(token);
continue;
}
if ((options &= OPTION_TOKEN_ONLY) != 0) {
throw genException("Non-token detected", sql);
}
// Detect comments.
if (ch == '-' && peek(sql, pos + 1) == '-') {
pos += 2;
pos = sql.indexOf('\n', pos);
if (pos < 0) {
// We disallow strings ending in an inline comment.
throw genException("Unterminated comment", sql);
}
pos++;
continue;
}
if (ch == '/' && peek(sql, pos + 1) == '*') {
pos += 2;
pos = sql.indexOf("*/", pos);
if (pos < 0) {
throw genException("Unterminated comment", sql);
}
pos += 2;
continue;
}
// Semicolon is never allowed.
if (ch == ';') {
throw genException("Semicolon is not allowed", sql);
}
// For this purpose, we can simply ignore other characters.
// (Note it doesn't handle the X'' literal properly and reports this X as a token,
// but that should be fine...)
pos++;
}
}
/**
* Test if given token is a
* SQLite reserved
* keyword.
*/
public static boolean isKeyword(@NonNull String token) {
switch (token.toUpperCase(Locale.US)) {
case "ABORT": case "ACTION": case "ADD": case "AFTER":
case "ALL": case "ALTER": case "ANALYZE": case "AND":
case "AS": case "ASC": case "ATTACH": case "AUTOINCREMENT":
case "BEFORE": case "BEGIN": case "BETWEEN": case "BINARY":
case "BY": case "CASCADE": case "CASE": case "CAST":
case "CHECK": case "COLLATE": case "COLUMN": case "COMMIT":
case "CONFLICT": case "CONSTRAINT": case "CREATE": case "CROSS":
case "CURRENT": case "CURRENT_DATE": case "CURRENT_TIME": case "CURRENT_TIMESTAMP":
case "DATABASE": case "DEFAULT": case "DEFERRABLE": case "DEFERRED":
case "DELETE": case "DESC": case "DETACH": case "DISTINCT":
case "DO": case "DROP": case "EACH": case "ELSE":
case "END": case "ESCAPE": case "EXCEPT": case "EXCLUDE":
case "EXCLUSIVE": case "EXISTS": case "EXPLAIN": case "FAIL":
case "FILTER": case "FOLLOWING": case "FOR": case "FOREIGN":
case "FROM": case "FULL": case "GLOB": case "GROUP":
case "GROUPS": case "HAVING": case "IF": case "IGNORE":
case "IMMEDIATE": case "IN": case "INDEX": case "INDEXED":
case "INITIALLY": case "INNER": case "INSERT": case "INSTEAD":
case "INTERSECT": case "INTO": case "IS": case "ISNULL":
case "JOIN": case "KEY": case "LEFT": case "LIKE":
case "LIMIT": case "MATCH": case "NATURAL": case "NO":
case "NOCASE": case "NOT": case "NOTHING": case "NOTNULL":
case "NULL": case "OF": case "OFFSET": case "ON":
case "OR": case "ORDER": case "OTHERS": case "OUTER":
case "OVER": case "PARTITION": case "PLAN": case "PRAGMA":
case "PRECEDING": case "PRIMARY": case "QUERY": case "RAISE":
case "RANGE": case "RECURSIVE": case "REFERENCES": case "REGEXP":
case "REINDEX": case "RELEASE": case "RENAME": case "REPLACE":
case "RESTRICT": case "RIGHT": case "ROLLBACK": case "ROW":
case "ROWS": case "RTRIM": case "SAVEPOINT": case "SELECT":
case "SET": case "TABLE": case "TEMP": case "TEMPORARY":
case "THEN": case "TIES": case "TO": case "TRANSACTION":
case "TRIGGER": case "UNBOUNDED": case "UNION": case "UNIQUE":
case "UPDATE": case "USING": case "VACUUM": case "VALUES":
case "VIEW": case "VIRTUAL": case "WHEN": case "WHERE":
case "WINDOW": case "WITH": case "WITHOUT":
return true;
default:
return false;
}
}
/**
* Test if given token is a
* SQLite reserved
* function.
*/
public static boolean isFunction(@NonNull String token) {
switch (token.toLowerCase(Locale.US)) {
case "abs": case "avg": case "char": case "coalesce":
case "count": case "glob": case "group_concat": case "hex":
case "ifnull": case "instr": case "length": case "like":
case "likelihood": case "likely": case "lower": case "ltrim":
case "max": case "min": case "nullif": case "random":
case "randomblob": case "replace": case "round": case "rtrim":
case "substr": case "sum": case "total": case "trim":
case "typeof": case "unicode": case "unlikely": case "upper":
case "zeroblob":
return true;
default:
return false;
}
}
/**
* Test if given token is a
* SQLite reserved type.
*/
public static boolean isType(@NonNull String token) {
switch (token.toUpperCase(Locale.US)) {
case "INT": case "INTEGER": case "TINYINT": case "SMALLINT":
case "MEDIUMINT": case "BIGINT": case "INT2": case "INT8":
case "CHARACTER": case "VARCHAR": case "NCHAR": case "NVARCHAR":
case "TEXT": case "CLOB": case "BLOB": case "REAL":
case "DOUBLE": case "FLOAT": case "NUMERIC": case "DECIMAL":
case "BOOLEAN": case "DATE": case "DATETIME":
return true;
default:
return false;
}
}
}