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<?php |
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|
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namespace WordPress\Reprint\Server; |
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|
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// phpcs:disable WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Database cursor errors are never HTML. |
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|
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/** |
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* Reads database rows through bounded, resumable, primary-key-ordered queries. |
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*/ |
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class DatabaseRowsReader { |
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|
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/** Prefix shared by every schema version of Reprint's internal MySQL progress table. */ |
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private const MYSQL_IMPORT_PROGRESS_TABLE_PREFIX = "__reprint_db_pull_progress_"; |
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|
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|
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/** @var mixed PDO or a PDO-compatible adapter. */ |
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private $db; |
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|
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/** @var array|null */ |
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private $current_pk_columns = null; |
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|
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/** |
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* Cursor bookmark containing the primary key of the last returned record. |
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* The next SELECT starts strictly after these values. |
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* |
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* @var array|null |
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*/ |
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private $last_pk_values = null; |
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|
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/** |
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* Fallback cursor for tables without a primary key. OFFSET pagination |
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* re-scans earlier rows and can drift when records are inserted or deleted. |
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* Consumers which require stable resume must reject non-empty unkeyed tables. |
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* |
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* @var int |
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*/ |
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private $current_offset = 0; |
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|
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/** @var string|null */ |
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private $current_table = null; |
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|
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/** @var mixed */ |
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private $current_result_set = null; |
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|
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/** |
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* Distinguishes an exhausted LIMIT batch from an empty fresh query. The |
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* latter means the current table is complete. |
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* |
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* @var int |
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*/ |
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private $rows_fetched_from_current_query = 0; |
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|
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/** @var array */ |
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private $tables_to_process; |
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|
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/** |
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* Column metadata cached by table and column name. Each column contains |
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* data_type (for example, varchar), column_type (for example, |
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* varchar(255)), and its nullable collation name. |
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* |
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* @var array<string,array<string,array{data_type:string,column_type:string,collation:?string}>> |
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*/ |
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private $column_type_cache = []; |
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|
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/** @var array<string,int> Maximum character bytes cached by collation. */ |
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private $maximum_character_bytes_by_collation = []; |
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|
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|
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/** @var array|null */ |
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private $current_row = null; |
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|
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/** @var bool */ |
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private $current_row_ends_query_batch = false; |
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|
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/** @var array|null */ |
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private $current_column_types = null; |
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|
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/** @var array|null */ |
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private $current_column_names = null; |
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|
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/** @var int */ |
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private $batch_size; |
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|
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/** @var int|null */ |
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private $query_time_limit_ms = null; |
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|
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/** @var array<string,list<array{column:string,value:string}>> Row exclusions keyed by table. */ |
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private $exclude_rows_by_table = []; |
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|
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/** @var string[] Table names omitted from automatic discovery. */ |
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private $exclude_tables = []; |
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|
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|
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/** |
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* Initializes the bounded database row reader. |
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* |
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* @param mixed $db PDO or a PDO-compatible adapter. |
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* @param array $options { |
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* Reader options. |
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* |
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* @type array|null $tables_to_process Tables to read, or null to discover them. |
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* @type int $batch_size Maximum records per query. |
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* @type int|null $query_time_limit_ms Maximum query duration in milliseconds. |
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* @type array $exclude_rows Table, column, and value exclusion rules. |
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* @type string[] $exclude_tables Table names to omit from automatic discovery. |
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* } |
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*/ |
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public function __construct($db, $options = []) |
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{ |
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$this->db = $db; |
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$this->tables_to_process = $options["tables_to_process"] ?? null; |
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$this->batch_size = max(1, (int) ( $options["batch_size"] ?? 250 )); |
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$this->exclude_tables = array_values(array_filter( |
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$options["exclude_tables"] ?? [], |
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"is_string" |
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)); |
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|
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if (isset($options["query_time_limit_ms"])) { |
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$limit = (int) $options["query_time_limit_ms"]; |
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$this->query_time_limit_ms = $limit > 0 ? $limit : null; |
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} |
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|
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if (isset($options["exclude_rows"]) && is_array($options["exclude_rows"])) { |
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foreach ($options["exclude_rows"] as $rule) { |
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if ( |
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!is_array($rule) || |
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!isset($rule["table"], $rule["column"], $rule["value"]) || |
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!is_string($rule["table"]) || |
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!is_string($rule["column"]) || |
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!is_string($rule["value"]) |
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) { |
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continue; |
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} |
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$this->exclude_rows_by_table[$rule["table"]][] = [ |
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"column" => $rule["column"], |
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"value" => $rule["value"], |
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]; |
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} |
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} |
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} |
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|
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/** |
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* Fetches the next row and advances the resume position. |
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* |
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* An exhausted batch opens another bounded query after the last primary |
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* key. A fresh query returning no rows means the table is complete. |
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*/ |
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public function next_record() |
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{ |
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$this->current_row_ends_query_batch = false; |
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if (!$this->current_result_set) { |
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$query = $this->build_select_query(); |
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try { |
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$this->current_result_set = $this->db->query($query); |
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} catch (\Exception $e) { |
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throw new \RuntimeException( |
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"Database query `{$query}` failed for table " . $this->quote_identifier($this->current_table) . ": " . $e->getMessage() |
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); |
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} |
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$this->rows_fetched_from_current_query = 0; |
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} |
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|
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$record = $this->current_result_set->fetch(PdoConstants::fetch_assoc()); |
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if (!$record) { |
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$this->current_result_set = null; |
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if ($this->rows_fetched_from_current_query === 0) { |
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return false; |
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} |
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if ($this->last_pk_values !== null || $this->current_offset > 0) { |
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return $this->next_record(); |
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} |
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return false; |
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} |
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|
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++$this->rows_fetched_from_current_query; |
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if ($this->current_column_names === null) { |
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$this->current_column_names = array_keys($record); |
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} |
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|
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if ($this->current_pk_columns && count($this->current_pk_columns) > 0) { |
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$this->last_pk_values = []; |
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foreach ($this->current_pk_columns as $column) { |
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if (!array_key_exists($column, $record)) { |
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throw new \RuntimeException( |
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"Primary key column '{$column}' missing from SELECT result for table " . |
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$this->quote_identifier($this->current_table) |
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); |
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} |
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$this->last_pk_values[$column] = $record[$column]; |
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} |
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} else { |
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++$this->current_offset; |
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} |
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|
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$this->current_row = $record; |
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if ($this->rows_fetched_from_current_query >= $this->batch_size) { |
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$this->current_row_ends_query_batch = true; |
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$this->release_current_result_set(); |
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} |
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return true; |
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} |
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|
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/** Drains unconsumed records and releases the active LIMIT-sized result set. */ |
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private function release_current_result_set() |
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{ |
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if ($this->current_result_set === null) { |
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return; |
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} |
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$record = $this->current_result_set->fetch(PdoConstants::fetch_assoc()); |
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while ($record !== false) { |
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$record = $this->current_result_set->fetch(PdoConstants::fetch_assoc()); |
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} |
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$this->current_result_set = null; |
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} |
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|
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/** Returns whether the table list has been initialized. */ |
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public function has_initialized_tables() |
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{ |
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return $this->tables_to_process !== null; |
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} |
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|
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/** Returns the table currently being read. */ |
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public function get_current_table() |
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{ |
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return $this->current_table; |
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} |
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|
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/** Returns the fetched record retained until its consumer clears it. */ |
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public function get_current_record() |
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{ |
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return $this->current_row; |
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} |
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|
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/** Clears the retained record after its consumer has processed it. */ |
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public function clear_current_record() |
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{ |
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$this->current_row = null; |
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$this->current_row_ends_query_batch = false; |
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} |
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|
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/** Returns whether the retained record is the final row of its bounded query. */ |
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public function is_current_record_at_query_batch_boundary() |
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{ |
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return $this->current_row_ends_query_batch; |
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} |
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|
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/** Returns column names in table order. */ |
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public function get_current_column_names() |
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{ |
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return $this->current_column_names; |
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} |
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|
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/** Returns primary key column names in ordinal order. */ |
| 254 |
public function get_current_primary_key_columns() |
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{ |
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return $this->current_pk_columns; |
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} |
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|
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/** Returns the maximum number of rows read by one query. */ |
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public function get_batch_size() |
| 261 |
{ |
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return $this->batch_size; |
| 263 |
} |
| 264 |
|
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/** |
| 266 |
* Returns the row reader fields needed to resume at the current position. |
| 267 |
* |
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* @return array { |
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* @type string|null $current_table Current table name. |
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* @type array|null $current_pk_columns Current primary key columns. |
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* @type array|null $last_pk_values Encoded primary key values. |
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* @type int $current_offset Offset for a table without a primary key. |
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* @type array|null $current_row Encoded retained record. |
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* @type bool $current_row_ends_query_batch Whether the retained record ends its query batch. |
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* @type array|null $current_column_names Current column names. |
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* } |
| 277 |
*/ |
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public function get_cursor_state() |
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{ |
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return [ |
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"current_table" => $this->current_table, |
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"current_pk_columns" => $this->current_pk_columns, |
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"last_pk_values" => $this->encode_database_values_for_cursor($this->last_pk_values), |
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"current_offset" => $this->current_offset, |
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"current_row" => $this->encode_database_values_for_cursor($this->current_row), |
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"current_row_ends_query_batch" => $this->current_row_ends_query_batch, |
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"current_column_names" => $this->current_column_names, |
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]; |
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} |
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|
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/** |
| 292 |
* Restores row reader fields from reader cursor data. |
| 293 |
* |
| 294 |
* @param array $cursor_data Reader cursor fields returned by get_cursor_state(). |
| 295 |
* @return bool Whether the cursor's current table still exists. |
| 296 |
*/ |
| 297 |
public function restore_cursor_state($cursor_data) |
| 298 |
{ |
| 299 |
$this->current_table = $cursor_data["current_table"] ?? null; |
| 300 |
if ($this->current_table !== null && !is_string($this->current_table)) { |
| 301 |
throw new \InvalidArgumentException( |
| 302 |
"Invalid cursor: current_table must be string or null, got " . gettype($this->current_table) |
| 303 |
); |
| 304 |
} |
| 305 |
$this->current_pk_columns = $cursor_data["current_pk_columns"] ?? null; |
| 306 |
$this->last_pk_values = $this->decode_database_values_from_cursor( |
| 307 |
$cursor_data["last_pk_values"] ?? null |
| 308 |
); |
| 309 |
$this->current_offset = $cursor_data["current_offset"] ?? 0; |
| 310 |
if (!is_int($this->current_offset) && !is_float($this->current_offset)) { |
| 311 |
throw new \InvalidArgumentException( |
| 312 |
"Invalid cursor: current_offset must be numeric, got " . gettype($this->current_offset) |
| 313 |
); |
| 314 |
} |
| 315 |
$this->current_offset = (int) $this->current_offset; |
| 316 |
$this->current_row = $this->decode_database_values_from_cursor( |
| 317 |
$cursor_data["current_row"] ?? null |
| 318 |
); |
| 319 |
$this->current_row_ends_query_batch = $cursor_data["current_row_ends_query_batch"] ?? false; |
| 320 |
if (!is_bool($this->current_row_ends_query_batch)) { |
| 321 |
throw new \InvalidArgumentException( |
| 322 |
"Invalid cursor: current_row_ends_query_batch must be boolean, got " . |
| 323 |
gettype($this->current_row_ends_query_batch) |
| 324 |
); |
| 325 |
} |
| 326 |
$this->current_column_names = $cursor_data["current_column_names"] ?? null; |
| 327 |
|
| 328 |
if ($this->tables_to_process === null) { |
| 329 |
$this->initialize_tables_to_process(); |
| 330 |
} |
| 331 |
if ($this->current_table) { |
| 332 |
$position = array_search($this->current_table, $this->tables_to_process, true); |
| 333 |
if ($position === false) { |
| 334 |
$this->current_table = null; |
| 335 |
return false; |
| 336 |
} |
| 337 |
reset($this->tables_to_process); |
| 338 |
while (key($this->tables_to_process) !== $position) { |
| 339 |
next($this->tables_to_process); |
| 340 |
} |
| 341 |
if ($this->get_primary_key_columns($this->current_table) !== $this->current_pk_columns) { |
| 342 |
throw new \RuntimeException( |
| 343 |
"Cannot restore the database row cursor because the primary key for table " . |
| 344 |
$this->quote_identifier($this->current_table) . " changed." |
| 345 |
); |
| 346 |
} |
| 347 |
$this->current_column_types = $this->get_column_types($this->current_table); |
| 348 |
if (empty($this->current_column_types)) { |
| 349 |
throw new \RuntimeException( |
| 350 |
"Table " . $this->quote_identifier($this->current_table) . " was dropped between export requests " . |
| 351 |
"(no columns found in SHOW FULL COLUMNS)" |
| 352 |
); |
| 353 |
} |
| 354 |
if ($this->current_column_names === null) { |
| 355 |
$this->current_column_names = array_keys($this->current_column_types); |
| 356 |
} |
| 357 |
} |
| 358 |
return true; |
| 359 |
} |
| 360 |
|
| 361 |
/** |
| 362 |
* Builds the next bounded, byte-preserving SELECT. |
| 363 |
* |
| 364 |
* Non-numeric, non-binary columns are cast to BINARY so MySQL returns raw |
| 365 |
* bytes instead of transcoding them through the connection character set. |
| 366 |
* A latin1 column read through utf8mb4 must retain its original bytes. |
| 367 |
*/ |
| 368 |
private function build_select_query() |
| 369 |
{ |
| 370 |
$select = "SELECT"; |
| 371 |
if ($this->query_time_limit_ms !== null) { |
| 372 |
// Prevent one slow table query from consuming the PHP time budget. |
| 373 |
$select .= " /*+ MAX_EXECUTION_TIME(" . $this->query_time_limit_ms . ") */"; |
| 374 |
} |
| 375 |
|
| 376 |
if ($this->current_column_types) { |
| 377 |
$select_parts = []; |
| 378 |
foreach ($this->current_column_types as $column => $column_info) { |
| 379 |
$quoted_column = $this->quote_identifier($column); |
| 380 |
if ( |
| 381 |
$this->is_numeric_type($column_info["data_type"]) || |
| 382 |
$this->is_binary_type($column_info["data_type"]) |
| 383 |
) { |
| 384 |
$select_parts[] = $quoted_column; |
| 385 |
} else { |
| 386 |
$select_parts[] = "CAST({$quoted_column} AS BINARY) AS {$quoted_column}"; |
| 387 |
} |
| 388 |
} |
| 389 |
$query = $select . " " . implode(", ", $select_parts) . |
| 390 |
" FROM " . $this->quote_identifier($this->current_table); |
| 391 |
} else { |
| 392 |
$query = $select . " * FROM " . $this->quote_identifier($this->current_table); |
| 393 |
} |
| 394 |
|
| 395 |
$where_conditions = $this->build_row_exclusion_where_conditions(); |
| 396 |
if ($this->current_pk_columns && count($this->current_pk_columns) > 0) { |
| 397 |
if ($this->last_pk_values) { |
| 398 |
$where_conditions[] = $this->build_pk_where_clause(); |
| 399 |
} |
| 400 |
if ($where_conditions) { |
| 401 |
$query .= " WHERE " . implode(" AND ", array_map(function ($condition) { |
| 402 |
return "({$condition})"; |
| 403 |
}, $where_conditions)); |
| 404 |
} |
| 405 |
$order_columns = array_map(function ($column) { |
| 406 |
return $this->build_primary_key_column_expression($column) . " ASC"; |
| 407 |
}, $this->current_pk_columns); |
| 408 |
$query .= " ORDER BY " . implode(", ", $order_columns); |
| 409 |
$query .= " LIMIT {$this->batch_size}"; |
| 410 |
} else { |
| 411 |
if ($where_conditions) { |
| 412 |
$query .= " WHERE " . implode(" AND ", array_map(function ($condition) { |
| 413 |
return "({$condition})"; |
| 414 |
}, $where_conditions)); |
| 415 |
} |
| 416 |
$query .= " LIMIT {$this->batch_size}"; |
| 417 |
if ($this->current_offset > 0) { |
| 418 |
// Best-effort pagination for tables without a primary key. |
| 419 |
$query .= " OFFSET {$this->current_offset}"; |
| 420 |
} |
| 421 |
} |
| 422 |
return $query; |
| 423 |
} |
| 424 |
|
| 425 |
private function build_row_exclusion_where_conditions() |
| 426 |
{ |
| 427 |
if (!$this->current_table || empty($this->exclude_rows_by_table[$this->current_table])) { |
| 428 |
return []; |
| 429 |
} |
| 430 |
$conditions = []; |
| 431 |
foreach ($this->exclude_rows_by_table[$this->current_table] as $rule) { |
| 432 |
$column = $rule["column"]; |
| 433 |
if (!isset($this->current_column_types[$column])) { |
| 434 |
continue; |
| 435 |
} |
| 436 |
$quoted_column = $this->quote_identifier($column); |
| 437 |
$encoded_value = base64_encode($rule["value"]); |
| 438 |
// NULL <> value is UNKNOWN, so preserve NULL explicitly. |
| 439 |
$conditions[] = "{$quoted_column} IS NULL OR {$quoted_column} <> FROM_BASE64('{$encoded_value}')"; |
| 440 |
} |
| 441 |
return $conditions; |
| 442 |
} |
| 443 |
|
| 444 |
/** |
| 445 |
* Builds the lexicographic condition after a composite primary key. |
| 446 |
* |
| 447 |
* For (a, b, c), this expands to: |
| 448 |
* (a > A) OR (a = A AND b > B) OR (a = A AND b = B AND c > C). |
| 449 |
* The expanded form works on MySQL versions which do not optimize row-value |
| 450 |
* comparisons well. |
| 451 |
*/ |
| 452 |
private function build_pk_where_clause() |
| 453 |
{ |
| 454 |
if (!$this->last_pk_values || count($this->current_pk_columns) === 0) { |
| 455 |
return "1=1"; |
| 456 |
} |
| 457 |
if (count($this->current_pk_columns) === 1) { |
| 458 |
$column = $this->current_pk_columns[0]; |
| 459 |
return $this->build_comparison($column, $this->last_pk_values[$column], ">"); |
| 460 |
} |
| 461 |
$conditions = []; |
| 462 |
$prefix_conditions = []; |
| 463 |
foreach ($this->current_pk_columns as $column) { |
| 464 |
$value = $this->last_pk_values[$column]; |
| 465 |
$parts = $prefix_conditions; |
| 466 |
$parts[] = $this->build_comparison($column, $value, ">"); |
| 467 |
$conditions[] = "(" . implode(" AND ", $parts) . ")"; |
| 468 |
$prefix_conditions[] = $this->build_comparison($column, $value, "="); |
| 469 |
} |
| 470 |
return "(" . implode(" OR ", $conditions) . ")"; |
| 471 |
} |
| 472 |
|
| 473 |
public function build_comparison($column, $value, $operator) |
| 474 |
{ |
| 475 |
$column_expression = $this->build_primary_key_column_expression($column); |
| 476 |
if ($value === null) { |
| 477 |
return $operator === "=" |
| 478 |
? "{$column_expression} IS NULL" |
| 479 |
: "{$column_expression} IS NOT NULL"; |
| 480 |
} |
| 481 |
if ($this->is_numeric_type($this->get_data_type($column))) { |
| 482 |
return "{$column_expression} {$operator} {$value}"; |
| 483 |
} |
| 484 |
return "{$column_expression} {$operator} FROM_BASE64('" . base64_encode($value) . "')"; |
| 485 |
} |
| 486 |
|
| 487 |
/** |
| 488 |
* Builds the column expression shared by primary-key comparison and order. |
| 489 |
* |
| 490 |
* Character columns retain their declared collation and remain bare so the |
| 491 |
* database can use a primary-key range scan. FROM_BASE64() has higher |
| 492 |
* coercibility than the column, so MySQL applies the column's character set |
| 493 |
* and collation without reading cursor bytes through the connection |
| 494 |
* character set. ENUM and SET use a binary cast because their index |
| 495 |
* positions and fetched string values differ. |
| 496 |
*/ |
| 497 |
private function build_primary_key_column_expression($column) |
| 498 |
{ |
| 499 |
$qualified_column = $this->quote_identifier($this->current_table) . "." . |
| 500 |
$this->quote_identifier($column); |
| 501 |
$data_type = strtoupper($this->get_data_type($column)); |
| 502 |
if ($this->is_numeric_type($data_type) || $this->is_binary_type($data_type)) { |
| 503 |
return $qualified_column; |
| 504 |
} |
| 505 |
if ($this->is_character_string_type($data_type)) { |
| 506 |
return $qualified_column; |
| 507 |
} |
| 508 |
return "CAST({$qualified_column} AS BINARY)"; |
| 509 |
} |
| 510 |
|
| 511 |
/** Returns primary key column names in ordinal order, or an empty array. */ |
| 512 |
private function get_primary_key_columns($table) |
| 513 |
{ |
| 514 |
$primary_key_columns = []; |
| 515 |
$columns_by_position = []; |
| 516 |
$has_usable_positions = true; |
| 517 |
$query = "SHOW INDEX FROM " . $this->quote_identifier($table); |
| 518 |
try { |
| 519 |
$statement = $this->db->query($query); |
| 520 |
} catch (\Exception $e) { |
| 521 |
throw new \RuntimeException( |
| 522 |
"Failed to get primary key columns for " . $this->quote_identifier($table) . ": " . $e->getMessage() . " Query: {$query}" |
| 523 |
); |
| 524 |
} |
| 525 |
$row = $statement->fetch(PdoConstants::fetch_assoc()); |
| 526 |
while ($row !== false) { |
| 527 |
if (!isset($row["Key_name"]) || strcasecmp($row["Key_name"], "PRIMARY") !== 0) { |
| 528 |
$row = $statement->fetch(PdoConstants::fetch_assoc()); |
| 529 |
continue; |
| 530 |
} |
| 531 |
|
| 532 |
$column = $row["Column_name"]; |
| 533 |
$primary_key_columns[] = $column; |
| 534 |
$position = $row["Seq_in_index"] ?? null; |
| 535 |
if (is_string($position) && ctype_digit($position)) { |
| 536 |
$position = intval($position); |
| 537 |
} |
| 538 |
if ( |
| 539 |
!is_int($position) || |
| 540 |
$position < 1 || |
| 541 |
isset($columns_by_position[$position]) |
| 542 |
) { |
| 543 |
$has_usable_positions = false; |
| 544 |
} else { |
| 545 |
$columns_by_position[$position] = $column; |
| 546 |
} |
| 547 |
$row = $statement->fetch(PdoConstants::fetch_assoc()); |
| 548 |
} |
| 549 |
|
| 550 |
if (!$has_usable_positions) { |
| 551 |
return $primary_key_columns; |
| 552 |
} |
| 553 |
ksort($columns_by_position, SORT_NUMERIC); |
| 554 |
return array_values($columns_by_position); |
| 555 |
} |
| 556 |
|
| 557 |
public function move_to_next_table() |
| 558 |
{ |
| 559 |
if ($this->tables_to_process === null) { |
| 560 |
return false; |
| 561 |
} |
| 562 |
if (!$this->current_table) { |
| 563 |
$this->current_table = reset($this->tables_to_process) ?: null; |
| 564 |
} else { |
| 565 |
$this->current_table = next($this->tables_to_process) ?: null; |
| 566 |
} |
| 567 |
if ($this->current_table) { |
| 568 |
$this->current_pk_columns = $this->get_primary_key_columns($this->current_table); |
| 569 |
$this->last_pk_values = null; |
| 570 |
$this->current_offset = 0; |
| 571 |
$this->current_column_types = $this->get_column_types($this->current_table); |
| 572 |
$this->current_column_names = array_keys($this->current_column_types); |
| 573 |
$this->current_row = null; |
| 574 |
$this->current_row_ends_query_batch = false; |
| 575 |
} |
| 576 |
return (bool) $this->current_table; |
| 577 |
} |
| 578 |
|
| 579 |
/** |
| 580 |
* Discovers BASE TABLEs and excludes views and Reprint progress tables. |
| 581 |
* |
| 582 |
* @TODO: Paginate databases with millions of tables. |
| 583 |
*/ |
| 584 |
public function initialize_tables_to_process() |
| 585 |
{ |
| 586 |
$this->tables_to_process = []; |
| 587 |
$statement = $this->db->query("SHOW FULL TABLES"); |
| 588 |
$row = $statement->fetch(PdoConstants::fetch_assoc()); |
| 589 |
while ($row !== false) { |
| 590 |
$values = array_values($row); |
| 591 |
$excluded = isset($values[0]) && stripos( |
| 592 |
$values[0], |
| 593 |
self::MYSQL_IMPORT_PROGRESS_TABLE_PREFIX |
| 594 |
) === 0; |
| 595 |
foreach ($this->exclude_tables as $excluded_table) { |
| 596 |
if (isset($values[0]) && strcasecmp($values[0], $excluded_table) === 0) { |
| 597 |
$excluded = true; |
| 598 |
break; |
| 599 |
} |
| 600 |
} |
| 601 |
if ( |
| 602 |
isset($values[0], $values[1]) |
| 603 |
&& strcasecmp($values[1], "BASE TABLE") === 0 |
| 604 |
&& !$excluded |
| 605 |
) { |
| 606 |
$this->tables_to_process[] = $values[0]; |
| 607 |
} |
| 608 |
$row = $statement->fetch(PdoConstants::fetch_assoc()); |
| 609 |
} |
| 610 |
} |
| 611 |
|
| 612 |
/** Returns cached column metadata for a table. */ |
| 613 |
private function get_column_types($table_name) |
| 614 |
{ |
| 615 |
if (isset($this->column_type_cache[$table_name])) { |
| 616 |
return $this->column_type_cache[$table_name]; |
| 617 |
} |
| 618 |
try { |
| 619 |
$statement = $this->db->query( |
| 620 |
"SHOW FULL COLUMNS FROM " . $this->quote_identifier($table_name) |
| 621 |
); |
| 622 |
} catch (\Exception $e) { |
| 623 |
throw new \RuntimeException( |
| 624 |
"Failed to get column types for " . $this->quote_identifier($table_name) . ": " . $e->getMessage() |
| 625 |
); |
| 626 |
} |
| 627 |
$columns = []; |
| 628 |
$row = $statement->fetch(PdoConstants::fetch_assoc()); |
| 629 |
while ($row !== false) { |
| 630 |
$column_type = $row["Type"]; |
| 631 |
$columns[$row["Field"]] = [ |
| 632 |
"data_type" => preg_replace('/[\s(].*$/', '', $column_type), |
| 633 |
"column_type" => $column_type, |
| 634 |
"collation" => $row["Collation"] ?? null, |
| 635 |
]; |
| 636 |
$row = $statement->fetch(PdoConstants::fetch_assoc()); |
| 637 |
} |
| 638 |
$this->column_type_cache[$table_name] = $columns; |
| 639 |
return $columns; |
| 640 |
} |
| 641 |
|
| 642 |
/** Identifies numeric types which the dump emits as bare literals. */ |
| 643 |
public function is_numeric_type($data_type) |
| 644 |
{ |
| 645 |
$data_type = strtoupper($data_type); |
| 646 |
foreach (["TINYINT", "SMALLINT", "MEDIUMINT", "INTEGER", "INT", "BIGINT", "DECIMAL", "NUMERIC", "FLOAT", "DOUBLE", "REAL", "BIT", "YEAR"] as $type) { |
| 647 |
if (strpos($data_type, $type) === 0) { |
| 648 |
return true; |
| 649 |
} |
| 650 |
} |
| 651 |
return false; |
| 652 |
} |
| 653 |
|
| 654 |
/** Identifies binary columns which do not need a binary SELECT cast. */ |
| 655 |
public function is_binary_type($data_type) |
| 656 |
{ |
| 657 |
$data_type = strtoupper($data_type); |
| 658 |
foreach (["BINARY", "VARBINARY", "TINYBLOB", "BLOB", "MEDIUMBLOB", "LONGBLOB"] as $type) { |
| 659 |
if (strpos($data_type, $type) === 0) { |
| 660 |
return true; |
| 661 |
} |
| 662 |
} |
| 663 |
return false; |
| 664 |
} |
| 665 |
|
| 666 |
/** Identifies character strings whose SQL substring ranges count characters. */ |
| 667 |
public function is_character_string_type($data_type) |
| 668 |
{ |
| 669 |
$data_type = strtoupper($data_type); |
| 670 |
foreach (["CHAR", "VARCHAR", "TINYTEXT", "TEXT", "MEDIUMTEXT", "LONGTEXT"] as $type) { |
| 671 |
if (strpos($data_type, $type) === 0) { |
| 672 |
return true; |
| 673 |
} |
| 674 |
} |
| 675 |
return false; |
| 676 |
} |
| 677 |
|
| 678 |
/** Returns the DATA_TYPE string for a column, or throws if unknown. */ |
| 679 |
public function get_data_type(string $column): string |
| 680 |
{ |
| 681 |
if (!isset($this->current_column_types[$column]["data_type"])) { |
| 682 |
throw new \RuntimeException( |
| 683 |
"No column type info for '{$column}' in table " . |
| 684 |
$this->quote_identifier($this->current_table) . |
| 685 |
". This is a bug — SHOW FULL COLUMNS should have returned it." |
| 686 |
); |
| 687 |
} |
| 688 |
return $this->current_column_types[$column]["data_type"]; |
| 689 |
} |
| 690 |
|
| 691 |
/** Returns the declared character set's maximum bytes per character. */ |
| 692 |
public function get_maximum_character_bytes(string $column): int |
| 693 |
{ |
| 694 |
if (!isset($this->current_column_types[$column])) { |
| 695 |
throw new \RuntimeException( |
| 696 |
"No column type info for '{$column}' in table " . |
| 697 |
$this->quote_identifier($this->current_table) . "." |
| 698 |
); |
| 699 |
} |
| 700 |
|
| 701 |
$collation = $this->current_column_types[$column]["collation"]; |
| 702 |
if ($collation === null) { |
| 703 |
return 1; |
| 704 |
} |
| 705 |
if (isset($this->maximum_character_bytes_by_collation[$collation])) { |
| 706 |
return $this->maximum_character_bytes_by_collation[$collation]; |
| 707 |
} |
| 708 |
|
| 709 |
$statement = $this->db->prepare( |
| 710 |
"SELECT character_sets.MAXLEN " . |
| 711 |
"FROM information_schema.COLLATIONS AS collations " . |
| 712 |
"JOIN information_schema.CHARACTER_SETS AS character_sets " . |
| 713 |
"ON character_sets.CHARACTER_SET_NAME = collations.CHARACTER_SET_NAME " . |
| 714 |
"WHERE collations.COLLATION_NAME = ?" |
| 715 |
); |
| 716 |
$statement->execute([$collation]); |
| 717 |
$maximum_character_bytes = (int) $statement->fetchColumn(); |
| 718 |
if ($maximum_character_bytes < 1) { |
| 719 |
// phpcs:disable WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Database metadata errors are never HTML. |
| 720 |
throw new \RuntimeException( |
| 721 |
"Cannot determine the maximum character byte length for column " . |
| 722 |
$this->quote_identifier($this->current_table) . "." . |
| 723 |
$this->quote_identifier($column) . " with collation {$collation}." |
| 724 |
); |
| 725 |
// phpcs:enable WordPress.Security.EscapeOutput.ExceptionNotEscaped |
| 726 |
} |
| 727 |
|
| 728 |
$this->maximum_character_bytes_by_collation[$collation] = $maximum_character_bytes; |
| 729 |
return $maximum_character_bytes; |
| 730 |
} |
| 731 |
|
| 732 |
/** Escapes backticks by doubling them: tricky`table becomes `tricky``table`. */ |
| 733 |
public function quote_identifier($identifier) |
| 734 |
{ |
| 735 |
return '`' . str_replace('`', '``', $identifier) . '`'; |
| 736 |
} |
| 737 |
|
| 738 |
/** |
| 739 |
* Encodes database strings for JSON cursor storage. |
| 740 |
* |
| 741 |
* JSON cannot represent arbitrary database bytes. The __binary__ marker |
| 742 |
* distinguishes strings which must be decoded when restoring the cursor. |
| 743 |
*/ |
| 744 |
public function encode_database_values_for_cursor($values) |
| 745 |
{ |
| 746 |
if ($values === null) { |
| 747 |
return null; |
| 748 |
} |
| 749 |
$encoded = []; |
| 750 |
foreach ($values as $column => $value) { |
| 751 |
$encoded[$column] = $value !== null && is_string($value) |
| 752 |
? ["__binary__" => base64_encode($value)] |
| 753 |
: $value; |
| 754 |
} |
| 755 |
return $encoded; |
| 756 |
} |
| 757 |
|
| 758 |
/** Restores database strings encoded by encode_database_values_for_cursor(). */ |
| 759 |
public function decode_database_values_from_cursor($values) |
| 760 |
{ |
| 761 |
if ($values === null) { |
| 762 |
return null; |
| 763 |
} |
| 764 |
$decoded = []; |
| 765 |
foreach ($values as $column => $value) { |
| 766 |
$decoded[$column] = is_array($value) && isset($value["__binary__"]) |
| 767 |
? base64_decode($value["__binary__"]) |
| 768 |
: $value; |
| 769 |
} |
| 770 |
return $decoded; |
| 771 |
} |
| 772 |
} |
| 773 |
|
