1.0.1: label for "Back up now", retention explained in the trash, occ times in the schedule's zone, single-file restore to a directory, leftovers of a stopped restore removed

- Admin page: an optional label (at most 100 characters) for a backup started with "Back up now";
  an (i) by "removed by retention policy" in the trash that explains what it means and until when
  the restore point can be brought back. backup:trash says the same below its list.
- backup:status, backup:list, backup:trash and backup:browse show times in the zone of the daily
  schedule and name it, instead of the server's UTC.
- backup:restore --to-directory of a file restored nothing: the path got a "/" appended.
- A restore removes "<name>.ngb-restore-<hex>" temporaries that a stopped restore left in the
  folders it writes to.
- Roadmap: the cron warning (#13), reading ahead from S3/SMB and --salvage move to 1.0.2.

lib/Repository/Repository.php

@@ -214,7 +214,8 @@ final class Repository {
 	}
 
 	/**
-	 * Restore a snapshot (or only paths starting with $prefix) into a local directory.
+	 * Restore a snapshot (or only paths starting with $prefix) into a local directory. A $prefix
+	 * "dir/file/" also restores the file "dir/file" itself.
 	 *
 	 * @param bool $stripPrefix write "$target/<path without $prefix>" instead of
 	 *             "$target/<full logical path>" (disaster recovery: restoring e.g. "data/" or
@@ -253,7 +254,7 @@ final class Repository {
 		$plan = new ReadAheadPlan(rtrim($target, '/') . '/.ngb-restore-spool-' . bin2hex(random_bytes(4)));
 		try {
 			foreach ($this->streamEntries($snapshotId) as $entry) {
-				if ($prefix !== '' && !str_starts_with($entry['p'], $prefix)) {
+				if (!self::underPrefix($entry['p'], $prefix)) {
 					continue;
 				}
 				foreach ($entry['b'] as $id) {
@@ -286,11 +287,15 @@ final class Repository {
 
 	private function restoreEntries(string $snapshotId, string $target, string $prefix, bool $stripPrefix, ?callable $heartbeat, ?ReadAheadPlan $plan): int {
 		$count = 0;
+		$cleaned = [];
 		foreach ($this->streamEntries($snapshotId) as $entry) {
-			if ($prefix !== '' && !str_starts_with($entry['p'], $prefix)) {
+			if (!self::underPrefix($entry['p'], $prefix)) {
 				continue;
 			}
-			$relPath = ($stripPrefix && $prefix !== '') ? substr($entry['p'], strlen(rtrim($prefix, '/')) + 1) : $entry['p'];
+			$relPath = $entry['p'];
+			if ($stripPrefix && $prefix !== '') {
+				$relPath = $entry['p'] === rtrim($prefix, '/') ? basename($entry['p']) : substr($entry['p'], strlen($prefix));
+			}
 			$dest = rtrim($target, '/') . '/' . $relPath;
 			if (!is_dir(dirname($dest))) {
 				mkdir(dirname($dest), 0700, true);
@@ -301,6 +306,10 @@ final class Repository {
 			if ($base === false || $dir === false || ($dir !== $base && !str_starts_with($dir, $base . '/')) || is_link($dest)) {
 				throw new RepositoryException('Refusing to write outside the restore directory: ' . $entry['p']);
 			}
+			if (!isset($cleaned[$dir])) {
+				self::removeStaleTemporaries($dir);
+				$cleaned[$dir] = true;
+			}
 			// Write next to the destination and rename after all blobs verified: at most one file
 			// is ever present twice.
 			$tmp = $dest . '.ngb-restore-' . bin2hex(random_bytes(6));
@@ -331,6 +340,30 @@ final class Repository {
 		return $count;
 	}
 
+	/** $prefix is "" (everything) or ends with "/"; the path without that "/" is a file to restore too. */
+	private static function underPrefix(string $path, string $prefix): bool {
+		return $prefix === '' || str_starts_with($path, $prefix) || $path === rtrim($prefix, '/');
+	}
+
+	/**
+	 * Remove what a restore that was stopped left in a directory this restore writes to:
+	 * "<name>.ngb-restore-<hex>" from here, ".<name>.ngb-restore-<hex>" from a restore through
+	 * Nextcloud. A files:scan would otherwise make them show up in Files.
+	 */
+	public static function removeStaleTemporaries(string $dir): void {
+		$names = scandir($dir);
+		foreach ($names === false ? [] : $names as $name) {
+			$path = $dir . '/' . $name;
+			if (self::isRestoreTemporary($name) && is_file($path) && !is_link($path)) {
+				@unlink($path);
+			}
+		}
+	}
+
+	public static function isRestoreTemporary(string $name): bool {
+		return preg_match('/.\.ngb-restore-[0-9a-f]{6}(?:[0-9a-f]{6})?$/', $name) === 1;
+	}
+
 	/**
 	 * Start writing a generated stream (e.g. a table dump) as blobs. Call flushPacks() when the
 	 * run is done, so the last pack is uploaded before anything references it.