Refine cache purgring

src/CacheInvalidation.php

@@ -12,11 +12,12 @@ namespace dokuwiki\plugin\luxtools;
 class CacheInvalidation
 {
     /**
-     * Purge the complete DokuWiki cache directory.
+     * Purge the DokuWiki cache directory, preserving the luxtools subfolder.
      *
-     * This removes all files and subdirectories inside the configured
-     * cache directory ($conf['cachedir']).  It is equivalent to running
-     * `rm -rf data/cache/*` on the server.
+     * Removes all files and subdirectories inside $conf['cachedir'] except
+     * the `luxtools/` subdirectory, which contains plugin-specific caches
+     * (thumbnails, pagelink mapping) that are expensive to rebuild and are
+     * managed separately via {@see purgePagelinks()} and {@see purgeThumbs()}.
      *
      * @return int Number of removed entries.
      */
@@ -29,17 +30,90 @@ class CacheInvalidation
             return 0;
         }
 
-        return self::removeDirectoryEntries($cacheDir);
+        return self::removeDirectoryEntries($cacheDir, ['luxtools']);
+    }
+
+    /**
+     * Purge the luxtools pagelink cache file.
+     *
+     * Deletes {@see PageLink::CACHE_FILE} from the luxtools cache sub-directory
+     * ($conf['cachedir']/luxtools/pagelink_cache.json). The file is rebuilt
+     * automatically on the next page request that needs it.
+     *
+     * @return int 1 if the file was removed, 0 otherwise.
+     */
+    public static function purgePagelinks(): int
+    {
+        global $conf;
+
+        $cacheDir = rtrim((string)($conf['cachedir'] ?? ''), '/');
+        if ($cacheDir === '') {
+            return 0;
+        }
+
+        $file = $cacheDir . '/luxtools/pagelink_cache.json';
+        if (!file_exists($file)) {
+            return 0;
+        }
+
+        return @unlink($file) ? 1 : 0;
+    }
+
+    /**
+     * Purge the luxtools thumbnail cache directory.
+     *
+     * Removes all files and sub-directories inside
+     * $conf['cachedir']/luxtools/thumbs. Thumbnails are regenerated
+     * on demand by file.php.
+     *
+     * @return int Number of removed entries.
+     */
+    public static function purgeThumbs(): int
+    {
+        global $conf;
+
+        $cacheDir = rtrim((string)($conf['cachedir'] ?? ''), '/');
+        if ($cacheDir === '') {
+            return 0;
+        }
+
+        $thumbsDir = $cacheDir . '/luxtools/thumbs';
+        if (!is_dir($thumbsDir)) {
+            return 0;
+        }
+
+        return self::removeDirectoryEntries($thumbsDir);
+    }
+
+    /**
+     * Execute a selective cache purge.
+     *
+     * Always purges the DokuWiki cache (skipping the luxtools subfolder).
+     * Optionally also purges the pagelinks cache and/or the thumbnail cache.
+     *
+     * @param bool $pagelinks Whether to also purge the pagelink cache.
+     * @param bool $thumbs    Whether to also purge the thumbnail cache.
+     * @return array{dokuwiki: int, pagelinks: int|null, thumbs: int|null}
+     *   Removed-entry counts per component; pagelinks/thumbs are null when not purged.
+     */
+    public static function purgeSelected(bool $pagelinks, bool $thumbs): array
+    {
+        return [
+            'dokuwiki'  => self::purgeAll(),
+            'pagelinks' => $pagelinks ? self::purgePagelinks() : null,
+            'thumbs'    => $thumbs    ? self::purgeThumbs()    : null,
+        ];
     }
 
     /**
      * Remove all files and subdirectories inside a directory
      * without removing the directory itself.
      *
-     * @param string $directory
+     * @param string   $directory
+     * @param string[] $skip      Entry names (not paths) to leave untouched.
      * @return int Number of removed files/directories.
      */
-    public static function removeDirectoryEntries(string $directory): int
+    public static function removeDirectoryEntries(string $directory, array $skip = []): int
     {
         if ($directory === '' || !is_dir($directory) || !is_readable($directory)) {
             return 0;
@@ -51,6 +125,7 @@ class CacheInvalidation
         $removed = 0;
         foreach ($entries as $entry) {
             if ($entry === '.' || $entry === '..') continue;
+            if ($skip !== [] && in_array($entry, $skip, true)) continue;
 
             $path = $directory . '/' . $entry;
             if (is_dir($path) && !is_link($path)) {