added FileSystem::open()

src/Utils/FileSystem.php

@@ -64,11 +64,7 @@ public static function copy(string $origin, string $target, bool $overwrite = tr
 			}
 		} else {
 			static::createDir(dirname($target));
-			if (
-				($s = @fopen($origin, 'rb'))
-				&& ($d = @fopen($target, 'wb'))
-				&& @stream_copy_to_stream($s, $d) === false
-			) { // @ is escalated to exception
+			if (@stream_copy_to_stream(static::open($origin, 'rb'), static::open($target, 'wb')) === false) { // @ is escalated to exception
 				throw new Nette\IOException(sprintf(
 					"Unable to copy file '%s' to '%s'. %s",
 					self::normalizePath($origin),
@@ -80,6 +76,25 @@ public static function copy(string $origin, string $target, bool $overwrite = tr
 	}
 
 
+	/**
+	 * Opens file and returns resource.
+	 * @return resource
+	 * @throws Nette\IOException  on error occurred
+	 */
+	public static function open(string $path, string $mode)
+	{
+		$f = @fopen($path, $mode); // @ is escalated to exception
+		if (!$f) {
+			throw new Nette\IOException(sprintf(
+				"Unable to open file '%s'. %s",
+				self::normalizePath($path),
+				Helpers::getLastError(),
+			));
+		}
+		return $f;
+	}
+
+
 	/**
 	 * Deletes a file or an entire directory if exists. If the directory is not empty, it deletes its contents first.
 	 * @throws Nette\IOException  on error occurred

tests/Utils/FileSystem.open.phpt

@@ -0,0 +1,24 @@
+<?php
+
+/**
+ * Test: Nette\Utils\FileSystem open()
+ */
+
+declare(strict_types=1);
+
+use Nette\Utils\FileSystem;
+use Tester\Assert;
+
+require __DIR__ . '/../bootstrap.php';
+
+
+test('open', function () {
+	$f = FileSystem::open(__FILE__, 'r');
+	Assert::type('resource', $f);
+});
+
+Assert::exception(
+	fn() => FileSystem::open('missing', 'r'),
+	Nette\IOException::class,
+	"Unable to open file 'missing'.%A%",
+);