add some support for rename on case insensitive local filesystems

lib/private/Files/Storage/Local.php

@@ -74,6 +74,8 @@ class Local extends \OC\Files\Storage\Common {
 
 	protected bool $unlinkOnTruncate;
 
+	protected bool $caseInsensitive = false;
+
 	public function __construct($arguments) {
 		if (!isset($arguments['datadir']) || !is_string($arguments['datadir'])) {
 			throw new \InvalidArgumentException('No data directory set for local storage');
@@ -93,6 +95,7 @@ public function __construct($arguments) {
 		$this->config = \OC::$server->get(IConfig::class);
 		$this->mimeTypeDetector = \OC::$server->get(IMimeTypeDetector::class);
 		$this->defUMask = $this->config->getSystemValue('localstorage.umask', 0022);
+		$this->caseInsensitive = $this->config->getSystemValueBool('localstorage.case_insensitive', false);
 
 		// support Write-Once-Read-Many file systems
 		$this->unlinkOnTruncate = $this->config->getSystemValueBool('localstorage.unlink_on_truncate', false);
@@ -162,13 +165,19 @@ public function opendir($path) {
 	}
 
 	public function is_dir($path) {
+		if ($this->caseInsensitive && !$this->file_exists($path)) {
+			return false;
+		}
 		if (str_ends_with($path, '/')) {
 			$path = substr($path, 0, -1);
 		}
 		return is_dir($this->getSourcePath($path));
 	}
 
 	public function is_file($path) {
+		if ($this->caseInsensitive && !$this->file_exists($path)) {
+			return false;
+		}
 		return is_file($this->getSourcePath($path));
 	}
 
@@ -271,7 +280,13 @@ public function isUpdatable($path) {
 	}
 
 	public function file_exists($path) {
-		return file_exists($this->getSourcePath($path));
+		if ($this->caseInsensitive) {
+			$fullPath = $this->getSourcePath($path);
+			$content = scandir(dirname($fullPath), SCANDIR_SORT_NONE);
+			return is_array($content) && array_search(basename($fullPath), $content) !== false;
+		} else {
+			return file_exists($this->getSourcePath($path));
+		}
 	}
 
 	public function filemtime($path) {
@@ -372,6 +387,11 @@ public function rename($source, $target): bool {
 		}
 
 		if (@rename($this->getSourcePath($source), $this->getSourcePath($target))) {
+			if ($this->caseInsensitive) {
+				if (mb_strtolower($target) === mb_strtolower($source) && !$this->file_exists($target)) {
+					return false;
+				}
+			}
 			return true;
 		}
 
@@ -388,6 +408,11 @@ public function copy($source, $target) {
 			}
 			$result = copy($this->getSourcePath($source), $this->getSourcePath($target));
 			umask($oldMask);
+			if ($this->caseInsensitive) {
+				if (mb_strtolower($target) === mb_strtolower($source) && !$this->file_exists($target)) {
+					return false;
+				}
+			}
 			return $result;
 		}
 	}