Add caching to avoid duplicate isPathIgnored() calls

Introduced an ignored_cache array in Distignore_Filter_Iterator to cache the results of isPathIgnored() checks. This eliminates duplicate checks:
- Once in hasChildren() when deciding whether to descend into directories
- Once in get_file_list() when categorizing files/directories

The cache is shared between both methods via the new isPathIgnoredCached() method, reducing redundant gitignore pattern matching for directories.

Co-authored-by: swissspidy <[email protected]>

Author: Copilot

src/Dist_Archive_Command.php

@@ -508,7 +508,7 @@ private function get_file_list( $source_dir_path, $excluded = false ) {
 		foreach ( $iterator as $item ) {
 			$relative_filepath = str_replace( $source_dir_path, '', $item->getPathname() );
 			try {
-				if ( $this->checker->isPathIgnored( $relative_filepath ) ) {
+				if ( $filter_iterator->isPathIgnoredCached( $relative_filepath ) ) {
 					$excluded_files[] = $relative_filepath;
 				} else {
 					$included_files[] = $relative_filepath;

src/Distignore_Filter_Iterator.php

@@ -22,6 +22,13 @@ class Distignore_Filter_Iterator extends RecursiveFilterIterator {
 	 */
 	private $source_dir_path;
 
+	/**
+	 * Cache for ignored status to avoid duplicate checks.
+	 *
+	 * @var array<string, bool>
+	 */
+	private $ignored_cache = [];
+
 	/**
 	 * Constructor.
 	 *
@@ -47,6 +54,20 @@ public function accept() {
 		return true;
 	}
 
+	/**
+	 * Check if a path is ignored, with caching to avoid duplicate checks.
+	 *
+	 * @param string $relative_filepath Relative file path to check.
+	 * @return bool True if the path is ignored, false otherwise.
+	 * @throws \Inmarelibero\GitIgnoreChecker\Exception\InvalidArgumentException
+	 */
+	public function isPathIgnoredCached( $relative_filepath ) {
+		if ( ! isset( $this->ignored_cache[ $relative_filepath ] ) ) {
+			$this->ignored_cache[ $relative_filepath ] = $this->checker->isPathIgnored( $relative_filepath );
+		}
+		return $this->ignored_cache[ $relative_filepath ];
+	}
+
 	/**
 	 * Check whether the current element has children that should be recursed into.
 	 * We return false for certain ignored directories to prevent descending into them.
@@ -81,7 +102,7 @@ public function hasChildren() {
 		}
 
 		try {
-			$is_ignored = $this->checker->isPathIgnored( $relative_filepath );
+			$is_ignored = $this->isPathIgnoredCached( $relative_filepath );
 
 			if ( ! $is_ignored ) {
 				// Not ignored, so descend.
@@ -100,7 +121,7 @@ public function hasChildren() {
 				// The actual name doesn't matter; we just need to verify the pattern applies to children.
 				$test_child = $relative_filepath . '/test';
 				try {
-					$child_ignored = $this->checker->isPathIgnored( $test_child );
+					$child_ignored = $this->isPathIgnoredCached( $test_child );
 					if ( $child_ignored ) {
 						// Child is also ignored, safe to skip descent.
 						return false;