refactor: split class-executor.php into 3 focused classes (300-line rule)

Extract PRAutoBlogger_Generation_Lock (DB mutex) and PRAutoBlogger_Ajax_Handlers (image/model/test AJAX) from the 482-line executor. Executor retains generation cron/AJAX + model registry at 299 lines. Document background generation flow in ARCHITECTURE.md. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-04-18 14:08:46 +07:00
parent 4c49e8593e
commit 41f1b13497
5 changed files with 339 additions and 224 deletions
--- a/includes/class-generation-lock.php
+++ b/includes/class-generation-lock.php
@@ -0,0 +1,95 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * Database-level atomic mutex for content generation.
+ *
+ * What: Provides acquire/release/check semantics for a single-writer generation lock.
+ * Who calls it: PRAutoBlogger_Executor (daily and manual generation), status polling fallback.
+ * Dependencies: WordPress $wpdb for direct SQL.
+ *
+ * Uses INSERT IGNORE against the wp_options UNIQUE index on option_name to
+ * guarantee only one PHP process can hold the lock at a time. Expired locks
+ * (>1 hour) are cleaned up automatically on acquire to prevent permanent deadlock.
+ *
+ * @see class-executor.php — Acquires/releases the lock around pipeline runs.
+ * @see class-ajax-handlers.php — Releases stale locks in the status fallback path.
+ */
+class PRAutoBlogger_Generation_Lock {
+
+	/** @var string Option name used as the lock key in wp_options. */
+	private const LOCK_NAME = 'prautoblogger_generation_lock';
+
+	/**
+	 * Acquire the generation mutex.
+	 *
+	 * Cleans up expired locks (>1 hour) first, then attempts an atomic INSERT
+	 * IGNORE. The UNIQUE constraint on option_name ensures only one caller wins.
+	 *
+	 * @return bool True if lock acquired, false if already held.
+	 */
+	public static function acquire(): bool {
+		global $wpdb;
+
+		// Clean up expired locks to prevent permanent deadlock.
+		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
+		$wpdb->query(
+			$wpdb->prepare(
+				"DELETE FROM {$wpdb->options} WHERE option_name = %s AND CAST(option_value AS UNSIGNED) < %d",
+				self::LOCK_NAME,
+				time() - HOUR_IN_SECONDS
+			)
+		);
+
+		// Atomic insert — UNIQUE constraint guarantees only one process succeeds.
+		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
+		$result = $wpdb->query(
+			$wpdb->prepare(
+				"INSERT IGNORE INTO {$wpdb->options} (option_name, option_value, autoload) VALUES (%s, %s, %s)",
+				self::LOCK_NAME,
+				(string) time(),
+				'no'
+			)
+		);
+
+		return $result > 0;
+	}
+
+	/**
+	 * Check if the generation lock is currently held.
+	 *
+	 * @return bool True if the lock exists (generation in progress or stuck).
+	 */
+	public static function is_locked(): bool {
+		global $wpdb;
+
+		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
+		$row = $wpdb->get_var(
+			$wpdb->prepare(
+				"SELECT option_value FROM {$wpdb->options} WHERE option_name = %s LIMIT 1",
+				self::LOCK_NAME
+			)
+		);
+
+		return null !== $row;
+	}
+
+	/**
+	 * Release the generation mutex.
+	 *
+	 * Safe to call even if the lock is not held (no-ops gracefully).
+	 *
+	 * Side effects: deletes the lock row from wp_options.
+	 */
+	public static function release(): void {
+		global $wpdb;
+
+		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching
+		$wpdb->query(
+			$wpdb->prepare(
+				"DELETE FROM {$wpdb->options} WHERE option_name = %s",
+				self::LOCK_NAME
+			)
+		);
+	}
+}