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Diffstat (limited to 'core/java/android/database/sqlite/SQLiteTokenizer.java')
-rw-r--r-- | core/java/android/database/sqlite/SQLiteTokenizer.java | 297 |
1 files changed, 297 insertions, 0 deletions
diff --git a/core/java/android/database/sqlite/SQLiteTokenizer.java b/core/java/android/database/sqlite/SQLiteTokenizer.java new file mode 100644 index 00000000000..7e7c3fb976c --- /dev/null +++ b/core/java/android/database/sqlite/SQLiteTokenizer.java @@ -0,0 +1,297 @@ +/* + * 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). + * <p> + * Based on sqlite3GetToken() in tokenzie.c in SQLite. + * <p> + * 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) + * <p> + * 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<String> tokenize(@Nullable String sql, int options) { + final ArrayList<String> 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<String> 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 + * <a href="https://www.sqlite.org/lang_keywords.html">SQLite reserved + * keyword</a>. + */ + 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 + * <a href="https://www.sqlite.org/lang_corefunc.html">SQLite reserved + * function</a>. + */ + 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 + * <a href="https://www.sqlite.org/datatype3.html">SQLite reserved type</a>. + */ + 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; + } + } +} |