Jeff Sharkey | 0e66ea6 | 2019-07-16 16:50:42 -0600 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2019 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package android.database.sqlite; |
| 18 | |
| 19 | import android.annotation.NonNull; |
| 20 | import android.annotation.Nullable; |
| 21 | |
| 22 | import java.util.ArrayList; |
| 23 | import java.util.List; |
| 24 | import java.util.Locale; |
| 25 | import java.util.function.Consumer; |
| 26 | |
| 27 | /** |
| 28 | * SQL Tokenizer specialized to extract tokens from SQL (snippets). |
| 29 | * <p> |
| 30 | * Based on sqlite3GetToken() in tokenzie.c in SQLite. |
| 31 | * <p> |
| 32 | * Source for v3.8.6 (which android uses): http://www.sqlite.org/src/artifact/ae45399d6252b4d7 |
| 33 | * (Latest source as of now: http://www.sqlite.org/src/artifact/78c8085bc7af1922) |
| 34 | * <p> |
| 35 | * Also draft spec: http://www.sqlite.org/draft/tokenreq.html |
| 36 | * |
| 37 | * @hide |
| 38 | */ |
| 39 | public class SQLiteTokenizer { |
| 40 | private static boolean isAlpha(char ch) { |
| 41 | return ('a' <= ch && ch <= 'z') || ('A' <= ch && ch <= 'Z') || (ch == '_'); |
| 42 | } |
| 43 | |
| 44 | private static boolean isNum(char ch) { |
| 45 | return ('0' <= ch && ch <= '9'); |
| 46 | } |
| 47 | |
| 48 | private static boolean isAlNum(char ch) { |
| 49 | return isAlpha(ch) || isNum(ch); |
| 50 | } |
| 51 | |
| 52 | private static boolean isAnyOf(char ch, String set) { |
| 53 | return set.indexOf(ch) >= 0; |
| 54 | } |
| 55 | |
| 56 | private static IllegalArgumentException genException(String message, String sql) { |
| 57 | throw new IllegalArgumentException(message + " in '" + sql + "'"); |
| 58 | } |
| 59 | |
| 60 | private static char peek(String s, int index) { |
| 61 | return index < s.length() ? s.charAt(index) : '\0'; |
| 62 | } |
| 63 | |
| 64 | public static final int OPTION_NONE = 0; |
| 65 | |
| 66 | /** |
| 67 | * Require that SQL contains only tokens; any comments or values will result |
| 68 | * in an exception. |
| 69 | */ |
| 70 | public static final int OPTION_TOKEN_ONLY = 1 << 0; |
| 71 | |
| 72 | /** |
| 73 | * Tokenize the given SQL, returning the list of each encountered token. |
| 74 | * |
| 75 | * @throws IllegalArgumentException if invalid SQL is encountered. |
| 76 | */ |
| 77 | public static List<String> tokenize(@Nullable String sql, int options) { |
| 78 | final ArrayList<String> res = new ArrayList<>(); |
| 79 | tokenize(sql, options, res::add); |
| 80 | return res; |
| 81 | } |
| 82 | |
| 83 | /** |
| 84 | * Tokenize the given SQL, sending each encountered token to the given |
| 85 | * {@link Consumer}. |
| 86 | * |
| 87 | * @throws IllegalArgumentException if invalid SQL is encountered. |
| 88 | */ |
| 89 | public static void tokenize(@Nullable String sql, int options, Consumer<String> checker) { |
| 90 | if (sql == null) { |
| 91 | return; |
| 92 | } |
| 93 | int pos = 0; |
| 94 | final int len = sql.length(); |
| 95 | while (pos < len) { |
| 96 | final char ch = peek(sql, pos); |
| 97 | |
| 98 | // Regular token. |
| 99 | if (isAlpha(ch)) { |
| 100 | final int start = pos; |
| 101 | pos++; |
| 102 | while (isAlNum(peek(sql, pos))) { |
| 103 | pos++; |
| 104 | } |
| 105 | final int end = pos; |
| 106 | |
| 107 | final String token = sql.substring(start, end); |
| 108 | checker.accept(token); |
| 109 | |
| 110 | continue; |
| 111 | } |
| 112 | |
| 113 | // Handle quoted tokens |
| 114 | if (isAnyOf(ch, "'\"`")) { |
| 115 | final int quoteStart = pos; |
| 116 | pos++; |
| 117 | |
| 118 | for (;;) { |
| 119 | pos = sql.indexOf(ch, pos); |
| 120 | if (pos < 0) { |
| 121 | throw genException("Unterminated quote", sql); |
| 122 | } |
| 123 | if (peek(sql, pos + 1) != ch) { |
| 124 | break; |
| 125 | } |
| 126 | // Quoted quote char -- e.g. "abc""def" is a single string. |
| 127 | pos += 2; |
| 128 | } |
| 129 | final int quoteEnd = pos; |
| 130 | pos++; |
| 131 | |
| 132 | if (ch != '\'') { |
| 133 | // Extract the token |
| 134 | final String tokenUnquoted = sql.substring(quoteStart + 1, quoteEnd); |
| 135 | |
| 136 | final String token; |
| 137 | |
| 138 | // Unquote if needed. i.e. "aa""bb" -> aa"bb |
| 139 | if (tokenUnquoted.indexOf(ch) >= 0) { |
| 140 | token = tokenUnquoted.replaceAll( |
| 141 | String.valueOf(ch) + ch, String.valueOf(ch)); |
| 142 | } else { |
| 143 | token = tokenUnquoted; |
| 144 | } |
| 145 | checker.accept(token); |
| 146 | } else { |
| 147 | if ((options &= OPTION_TOKEN_ONLY) != 0) { |
| 148 | throw genException("Non-token detected", sql); |
| 149 | } |
| 150 | } |
| 151 | continue; |
| 152 | } |
| 153 | // Handle tokens enclosed in [...] |
| 154 | if (ch == '[') { |
| 155 | final int quoteStart = pos; |
| 156 | pos++; |
| 157 | |
| 158 | pos = sql.indexOf(']', pos); |
| 159 | if (pos < 0) { |
| 160 | throw genException("Unterminated quote", sql); |
| 161 | } |
| 162 | final int quoteEnd = pos; |
| 163 | pos++; |
| 164 | |
| 165 | final String token = sql.substring(quoteStart + 1, quoteEnd); |
| 166 | |
| 167 | checker.accept(token); |
| 168 | continue; |
| 169 | } |
| 170 | if ((options &= OPTION_TOKEN_ONLY) != 0) { |
| 171 | throw genException("Non-token detected", sql); |
| 172 | } |
| 173 | |
| 174 | // Detect comments. |
| 175 | if (ch == '-' && peek(sql, pos + 1) == '-') { |
| 176 | pos += 2; |
| 177 | pos = sql.indexOf('\n', pos); |
| 178 | if (pos < 0) { |
| 179 | // We disallow strings ending in an inline comment. |
| 180 | throw genException("Unterminated comment", sql); |
| 181 | } |
| 182 | pos++; |
| 183 | |
| 184 | continue; |
| 185 | } |
| 186 | if (ch == '/' && peek(sql, pos + 1) == '*') { |
| 187 | pos += 2; |
| 188 | pos = sql.indexOf("*/", pos); |
| 189 | if (pos < 0) { |
| 190 | throw genException("Unterminated comment", sql); |
| 191 | } |
| 192 | pos += 2; |
| 193 | |
| 194 | continue; |
| 195 | } |
| 196 | |
| 197 | // Semicolon is never allowed. |
| 198 | if (ch == ';') { |
| 199 | throw genException("Semicolon is not allowed", sql); |
| 200 | } |
| 201 | |
| 202 | // For this purpose, we can simply ignore other characters. |
| 203 | // (Note it doesn't handle the X'' literal properly and reports this X as a token, |
| 204 | // but that should be fine...) |
| 205 | pos++; |
| 206 | } |
| 207 | } |
| 208 | |
| 209 | /** |
| 210 | * Test if given token is a |
| 211 | * <a href="https://www.sqlite.org/lang_keywords.html">SQLite reserved |
| 212 | * keyword</a>. |
| 213 | */ |
| 214 | public static boolean isKeyword(@NonNull String token) { |
| 215 | switch (token.toUpperCase(Locale.US)) { |
| 216 | case "ABORT": case "ACTION": case "ADD": case "AFTER": |
| 217 | case "ALL": case "ALTER": case "ANALYZE": case "AND": |
| 218 | case "AS": case "ASC": case "ATTACH": case "AUTOINCREMENT": |
| 219 | case "BEFORE": case "BEGIN": case "BETWEEN": case "BINARY": |
| 220 | case "BY": case "CASCADE": case "CASE": case "CAST": |
| 221 | case "CHECK": case "COLLATE": case "COLUMN": case "COMMIT": |
| 222 | case "CONFLICT": case "CONSTRAINT": case "CREATE": case "CROSS": |
| 223 | case "CURRENT": case "CURRENT_DATE": case "CURRENT_TIME": case "CURRENT_TIMESTAMP": |
| 224 | case "DATABASE": case "DEFAULT": case "DEFERRABLE": case "DEFERRED": |
| 225 | case "DELETE": case "DESC": case "DETACH": case "DISTINCT": |
| 226 | case "DO": case "DROP": case "EACH": case "ELSE": |
| 227 | case "END": case "ESCAPE": case "EXCEPT": case "EXCLUDE": |
| 228 | case "EXCLUSIVE": case "EXISTS": case "EXPLAIN": case "FAIL": |
| 229 | case "FILTER": case "FOLLOWING": case "FOR": case "FOREIGN": |
| 230 | case "FROM": case "FULL": case "GLOB": case "GROUP": |
| 231 | case "GROUPS": case "HAVING": case "IF": case "IGNORE": |
| 232 | case "IMMEDIATE": case "IN": case "INDEX": case "INDEXED": |
| 233 | case "INITIALLY": case "INNER": case "INSERT": case "INSTEAD": |
| 234 | case "INTERSECT": case "INTO": case "IS": case "ISNULL": |
| 235 | case "JOIN": case "KEY": case "LEFT": case "LIKE": |
| 236 | case "LIMIT": case "MATCH": case "NATURAL": case "NO": |
| 237 | case "NOCASE": case "NOT": case "NOTHING": case "NOTNULL": |
| 238 | case "NULL": case "OF": case "OFFSET": case "ON": |
| 239 | case "OR": case "ORDER": case "OTHERS": case "OUTER": |
| 240 | case "OVER": case "PARTITION": case "PLAN": case "PRAGMA": |
| 241 | case "PRECEDING": case "PRIMARY": case "QUERY": case "RAISE": |
| 242 | case "RANGE": case "RECURSIVE": case "REFERENCES": case "REGEXP": |
| 243 | case "REINDEX": case "RELEASE": case "RENAME": case "REPLACE": |
| 244 | case "RESTRICT": case "RIGHT": case "ROLLBACK": case "ROW": |
| 245 | case "ROWS": case "RTRIM": case "SAVEPOINT": case "SELECT": |
| 246 | case "SET": case "TABLE": case "TEMP": case "TEMPORARY": |
| 247 | case "THEN": case "TIES": case "TO": case "TRANSACTION": |
| 248 | case "TRIGGER": case "UNBOUNDED": case "UNION": case "UNIQUE": |
| 249 | case "UPDATE": case "USING": case "VACUUM": case "VALUES": |
| 250 | case "VIEW": case "VIRTUAL": case "WHEN": case "WHERE": |
| 251 | case "WINDOW": case "WITH": case "WITHOUT": |
| 252 | return true; |
| 253 | default: |
| 254 | return false; |
| 255 | } |
| 256 | } |
| 257 | |
| 258 | /** |
| 259 | * Test if given token is a |
| 260 | * <a href="https://www.sqlite.org/lang_corefunc.html">SQLite reserved |
| 261 | * function</a>. |
| 262 | */ |
| 263 | public static boolean isFunction(@NonNull String token) { |
| 264 | switch (token.toLowerCase(Locale.US)) { |
| 265 | case "abs": case "avg": case "char": case "coalesce": |
| 266 | case "count": case "glob": case "group_concat": case "hex": |
| 267 | case "ifnull": case "instr": case "length": case "like": |
| 268 | case "likelihood": case "likely": case "lower": case "ltrim": |
| 269 | case "max": case "min": case "nullif": case "random": |
| 270 | case "randomblob": case "replace": case "round": case "rtrim": |
| 271 | case "substr": case "sum": case "total": case "trim": |
| 272 | case "typeof": case "unicode": case "unlikely": case "upper": |
| 273 | case "zeroblob": |
| 274 | return true; |
| 275 | default: |
| 276 | return false; |
| 277 | } |
| 278 | } |
| 279 | |
| 280 | /** |
| 281 | * Test if given token is a |
| 282 | * <a href="https://www.sqlite.org/datatype3.html">SQLite reserved type</a>. |
| 283 | */ |
| 284 | public static boolean isType(@NonNull String token) { |
| 285 | switch (token.toUpperCase(Locale.US)) { |
| 286 | case "INT": case "INTEGER": case "TINYINT": case "SMALLINT": |
| 287 | case "MEDIUMINT": case "BIGINT": case "INT2": case "INT8": |
| 288 | case "CHARACTER": case "VARCHAR": case "NCHAR": case "NVARCHAR": |
| 289 | case "TEXT": case "CLOB": case "BLOB": case "REAL": |
| 290 | case "DOUBLE": case "FLOAT": case "NUMERIC": case "DECIMAL": |
| 291 | case "BOOLEAN": case "DATE": case "DATETIME": |
| 292 | return true; |
| 293 | default: |
| 294 | return false; |
| 295 | } |
| 296 | } |
| 297 | } |