| 1 |
<?php declare(strict_types = 1); |
| 2 |
|
| 3 |
/* |
| 4 |
* The SQLite connection uses PDO. Enable PDO function calls: |
| 5 |
* phpcs:disable WordPress.DB.RestrictedClasses.mysql__PDO |
| 6 |
*/ |
| 7 |
|
| 8 |
/** |
| 9 |
* SQLite connection. |
| 10 |
* |
| 11 |
* This class configures and encapsulates the connection to an SQLite database. |
| 12 |
* It requires PDO with the SQLite driver, and currently, it is only a simple |
| 13 |
* wrapper that leaks some of the PDO APIs (returns PDOStatement values, etc.). |
| 14 |
* In the future, we may abstract it away from PDO and support SQLite3 as well. |
| 15 |
* |
| 16 |
* @access private |
| 17 |
*/ |
| 18 |
class WP_SQLite_Connection { |
| 19 |
/** |
| 20 |
* The default timeout in seconds for SQLite to wait for a writable lock. |
| 21 |
*/ |
| 22 |
const DEFAULT_SQLITE_TIMEOUT = 10; |
| 23 |
|
| 24 |
/** |
| 25 |
* The supported SQLite journal modes. |
| 26 |
* |
| 27 |
* See: https://www.sqlite.org/pragma.html#pragma_journal_mode |
| 28 |
*/ |
| 29 |
const SQLITE_JOURNAL_MODES = array( |
| 30 |
'DELETE', |
| 31 |
'TRUNCATE', |
| 32 |
'PERSIST', |
| 33 |
'MEMORY', |
| 34 |
'WAL', |
| 35 |
'OFF', |
| 36 |
); |
| 37 |
|
| 38 |
/** |
| 39 |
* The supported SQLite synchronous settings. |
| 40 |
* |
| 41 |
* The list is indexed by the corresponding numeric setting values (0 to 3). |
| 42 |
* |
| 43 |
* See: https://www.sqlite.org/pragma.html#pragma_synchronous |
| 44 |
*/ |
| 45 |
const SQLITE_SYNCHRONOUS_SETTINGS = array( |
| 46 |
'OFF', |
| 47 |
'NORMAL', |
| 48 |
'FULL', |
| 49 |
'EXTRA', |
| 50 |
); |
| 51 |
|
| 52 |
/** |
| 53 |
* The PDO connection for SQLite. |
| 54 |
* |
| 55 |
* @var PDO |
| 56 |
*/ |
| 57 |
private $pdo; |
| 58 |
|
| 59 |
/** |
| 60 |
* A query logger callback. |
| 61 |
* |
| 62 |
* @var (callable(string, array): void)|null |
| 63 |
*/ |
| 64 |
private $query_logger = null; |
| 65 |
|
| 66 |
/** |
| 67 |
* Constructor. |
| 68 |
* |
| 69 |
* Set up an SQLite connection. |
| 70 |
* |
| 71 |
* @param array $options { |
| 72 |
* An array of options. |
| 73 |
* |
| 74 |
* @type string|null $path Optional. SQLite database path. |
| 75 |
* For in-memory database, use ':memory:'. |
| 76 |
* Must be set when PDO instance is not provided. |
| 77 |
* @type PDO|null $pdo Optional. PDO instance with SQLite connection. |
| 78 |
* If not provided, a new PDO instance will be created. |
| 79 |
* @type int|null $timeout Optional. SQLite timeout in seconds. |
| 80 |
* The time to wait for a writable lock. |
| 81 |
* @type string|null $journal_mode Optional. SQLite journal mode. Defaults to WAL. |
| 82 |
* @type string|int|null $synchronous Optional. SQLite synchronous setting. Defaults to |
| 83 |
* NORMAL when the effective journal mode is WAL. |
| 84 |
* @type array $pdo_options Optional. PDO constructor options. |
| 85 |
* } |
| 86 |
* |
| 87 |
* @throws InvalidArgumentException When some connection options are invalid. |
| 88 |
* @throws PDOException When the driver initialization fails. |
| 89 |
*/ |
| 90 |
public function __construct( array $options ) { |
| 91 |
// Setup PDO connection. |
| 92 |
if ( isset( $options['pdo'] ) && $options['pdo'] instanceof PDO ) { |
| 93 |
$this->pdo = $options['pdo']; |
| 94 |
} else { |
| 95 |
if ( ! isset( $options['path'] ) || ! is_string( $options['path'] ) ) { |
| 96 |
throw new InvalidArgumentException( 'Option "path" is required when "pdo" is not provided.' ); |
| 97 |
} |
| 98 |
$pdo_class = PHP_VERSION_ID >= 80400 ? Pdo\Sqlite::class : PDO::class; |
| 99 |
$pdo_options = $options['pdo_options'] ?? array(); |
| 100 |
|
| 101 |
// Internal driver operations require exceptions regardless of the |
| 102 |
// caller-visible WP_MySQL_On_SQLite::ATTR_ERRMODE setting. |
| 103 |
$pdo_options[ PDO::ATTR_ERRMODE ] = PDO::ERRMODE_EXCEPTION; |
| 104 |
$this->pdo = new $pdo_class( 'sqlite:' . $options['path'], null, null, $pdo_options ); |
| 105 |
} |
| 106 |
|
| 107 |
// Throw exceptions on error. |
| 108 |
$this->pdo->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION ); |
| 109 |
|
| 110 |
// Configure SQLite timeout. |
| 111 |
if ( isset( $options['timeout'] ) && is_int( $options['timeout'] ) ) { |
| 112 |
$timeout = $options['timeout']; |
| 113 |
} else { |
| 114 |
$timeout = self::DEFAULT_SQLITE_TIMEOUT; |
| 115 |
} |
| 116 |
$this->pdo->setAttribute( PDO::ATTR_TIMEOUT, $timeout ); |
| 117 |
|
| 118 |
// Configure SQLite journal mode. Default to WAL for best throughput. |
| 119 |
$effective_journal_mode = null; |
| 120 |
$journal_mode = $options['journal_mode'] ?? 'WAL'; |
| 121 |
if ( is_string( $journal_mode ) ) { |
| 122 |
$journal_mode = strtoupper( $journal_mode ); |
| 123 |
} |
| 124 |
if ( ! in_array( $journal_mode, self::SQLITE_JOURNAL_MODES, true ) ) { |
| 125 |
throw new InvalidArgumentException( |
| 126 |
sprintf( 'Invalid SQLite journal mode: %s.', $options['journal_mode'] ) |
| 127 |
); |
| 128 |
} |
| 129 |
try { |
| 130 |
$effective_journal_mode = strtoupper( |
| 131 |
(string) $this->query( 'PRAGMA journal_mode = ' . $journal_mode )->fetchColumn() |
| 132 |
); |
| 133 |
} catch ( PDOException $e ) { |
| 134 |
// WAL may be unavailable in some environments, such as on network |
| 135 |
// filesystems. When it is explicitly configured, surface the error. |
| 136 |
// Otherwise, fall back to the default SQLite behavior. |
| 137 |
if ( isset( $options['journal_mode'] ) ) { |
| 138 |
throw $e; |
| 139 |
} |
| 140 |
} |
| 141 |
|
| 142 |
/* |
| 143 |
* Configure SQLite synchronous setting. Default to NORMAL for WAL mode. |
| 144 |
* |
| 145 |
* WAL improves read/write concurrency and "synchronous = NORMAL" avoids |
| 146 |
* frequent sync to the main database, which could become a bottleneck. |
| 147 |
* In WAL mode, NORMAL is safe and recommended. From the SQLite docs: |
| 148 |
* |
| 149 |
* The synchronous=NORMAL setting provides the best balance between |
| 150 |
* performance and safety for most applications running in WAL mode. |
| 151 |
* You lose durability across power loss with synchronous NORMAL in WAL |
| 152 |
* mode, but that is not important for most applications. Transactions |
| 153 |
* are still atomic, consistent, and isolated, which are the most |
| 154 |
* important characteristics in most use cases. |
| 155 |
* |
| 156 |
* SQLite defaults to "synchronous = FULL" to avoid data corruption with |
| 157 |
* other journal modes. With WAL, this is not necessary. |
| 158 |
* |
| 159 |
* See: https://sqlite.org/pragma.html#pragma_synchronous |
| 160 |
*/ |
| 161 |
$synchronous = $options['synchronous'] ?? null; |
| 162 |
if ( isset( $synchronous ) ) { |
| 163 |
// Validate and normalize explicitly provided synchronous value. |
| 164 |
if ( is_int( $synchronous ) && isset( self::SQLITE_SYNCHRONOUS_SETTINGS[ $synchronous ] ) ) { |
| 165 |
$synchronous = self::SQLITE_SYNCHRONOUS_SETTINGS[ $synchronous ]; |
| 166 |
} elseif ( is_string( $synchronous ) ) { |
| 167 |
$synchronous = strtoupper( $synchronous ); |
| 168 |
} |
| 169 |
if ( ! in_array( $synchronous, self::SQLITE_SYNCHRONOUS_SETTINGS, true ) ) { |
| 170 |
throw new InvalidArgumentException( |
| 171 |
sprintf( 'Invalid SQLite synchronous setting: %s.', $options['synchronous'] ) |
| 172 |
); |
| 173 |
} |
| 174 |
} elseif ( 'WAL' === $effective_journal_mode ) { |
| 175 |
// Default to NORMAL for WAL mode. |
| 176 |
$synchronous = 'NORMAL'; |
| 177 |
} |
| 178 |
if ( in_array( $synchronous, self::SQLITE_SYNCHRONOUS_SETTINGS, true ) ) { |
| 179 |
$this->query( 'PRAGMA synchronous = ' . $synchronous ); |
| 180 |
} |
| 181 |
} |
| 182 |
|
| 183 |
/** |
| 184 |
* Execute a query in SQLite. |
| 185 |
* |
| 186 |
* @param string $sql The query to execute. |
| 187 |
* @param array $params The query parameters. |
| 188 |
* @throws PDOException When the query execution fails. |
| 189 |
* @return PDOStatement The PDO statement object. |
| 190 |
*/ |
| 191 |
public function query( string $sql, array $params = array() ): PDOStatement { |
| 192 |
if ( $this->query_logger ) { |
| 193 |
( $this->query_logger )( $sql, $params ); |
| 194 |
} |
| 195 |
$stmt = $this->pdo->prepare( $sql ); |
| 196 |
$stmt->execute( $params ); |
| 197 |
return $stmt; |
| 198 |
} |
| 199 |
|
| 200 |
/** |
| 201 |
* Prepare a SQLite query for execution. |
| 202 |
* |
| 203 |
* @param string $sql The query to prepare. |
| 204 |
* @return PDOStatement The prepared statement. |
| 205 |
* @throws PDOException When the query preparation fails. |
| 206 |
*/ |
| 207 |
public function prepare( string $sql ): PDOStatement { |
| 208 |
if ( $this->query_logger ) { |
| 209 |
( $this->query_logger )( $sql, array() ); |
| 210 |
} |
| 211 |
return $this->pdo->prepare( $sql ); |
| 212 |
} |
| 213 |
|
| 214 |
/** |
| 215 |
* Returns the ID of the last inserted row. |
| 216 |
* |
| 217 |
* @return string The ID of the last inserted row. |
| 218 |
*/ |
| 219 |
public function get_last_insert_id(): string { |
| 220 |
return $this->pdo->lastInsertId(); |
| 221 |
} |
| 222 |
|
| 223 |
/** |
| 224 |
* Quote a value for use in a query. |
| 225 |
* |
| 226 |
* @param mixed $value The value to quote. |
| 227 |
* @param int $type The type of the value. |
| 228 |
* @return string The quoted value. |
| 229 |
*/ |
| 230 |
public function quote( $value, int $type = PDO::PARAM_STR ): string { |
| 231 |
return $this->pdo->quote( $value, $type ); |
| 232 |
} |
| 233 |
|
| 234 |
/** |
| 235 |
* Quote an SQLite identifier. |
| 236 |
* |
| 237 |
* Wraps the identifier in backticks and escapes backtick characters within. |
| 238 |
* |
| 239 |
* --- |
| 240 |
* |
| 241 |
* Quoted identifiers in SQLite are represented by string constants: |
| 242 |
* |
| 243 |
* A string constant is formed by enclosing the string in single quotes ('). |
| 244 |
* A single quote within the string can be encoded by putting two single |
| 245 |
* quotes in a row - as in Pascal. C-style escapes using the backslash |
| 246 |
* character are not supported because they are not standard SQL. |
| 247 |
* |
| 248 |
* See: https://www.sqlite.org/lang_expr.html#literal_values_constants_ |
| 249 |
* |
| 250 |
* Although sparsely documented, this applies to backtick and double quoted |
| 251 |
* string constants as well, so only the quote character needs to be escaped. |
| 252 |
* |
| 253 |
* For more details, see the grammar for SQLite table and column names: |
| 254 |
* |
| 255 |
* - https://github.com/sqlite/sqlite/blob/873fc5dff2a781251f2c9bd2c791a5fac45b7a2b/src/tokenize.c#L395-L419 |
| 256 |
* - https://github.com/sqlite/sqlite/blob/873fc5dff2a781251f2c9bd2c791a5fac45b7a2b/src/parse.y#L321-L338 |
| 257 |
* |
| 258 |
* --- |
| 259 |
* |
| 260 |
* We use backtick quotes instead of the SQL standard double quotes, due to |
| 261 |
* an SQLite quirk causing double-quoted strings to be accepted as literals: |
| 262 |
* |
| 263 |
* This misfeature means that a misspelled double-quoted identifier will |
| 264 |
* be interpreted as a string literal, rather than generating an error. |
| 265 |
* |
| 266 |
* See: https://www.sqlite.org/quirks.html#double_quoted_string_literals_are_accepted |
| 267 |
* |
| 268 |
* @param string $unquoted_identifier The unquoted identifier value. |
| 269 |
* @return string The quoted identifier value. |
| 270 |
*/ |
| 271 |
public function quote_identifier( string $unquoted_identifier ): string { |
| 272 |
return '`' . str_replace( '`', '``', $unquoted_identifier ) . '`'; |
| 273 |
} |
| 274 |
|
| 275 |
/** |
| 276 |
* Get the PDO object. |
| 277 |
* |
| 278 |
* @return PDO |
| 279 |
*/ |
| 280 |
public function get_pdo(): PDO { |
| 281 |
return $this->pdo; |
| 282 |
} |
| 283 |
|
| 284 |
/** |
| 285 |
* Set or clear a logger for SQLite queries. |
| 286 |
* |
| 287 |
* @param (callable(string, array): void)|null $logger A query logger callback, or null to clear it. |
| 288 |
*/ |
| 289 |
public function set_query_logger( ?callable $logger ): void { |
| 290 |
$this->query_logger = $logger; |
| 291 |
} |
| 292 |
} |
| 293 |
|
