[NFR] Improve Phalcon\Autoloader speed

[dugwood]

Expected and Actual Behavior

Phalcon\Autoloader is slow because the is_file() test is slow. With a lot of files, this can add a serious amount of time, especially if the whole PHP run is small.

See #10472 for instance, and specifically comment: #10472 (comment)

Reproduce script:

$time = -1 * microtime(true);
include __DIR__.'/../library/ModelParameters.php';
include __DIR__.'/../models/Model.php';
include __DIR__.'/../models/Promotion.php';
$files = 3;
foreach (glob(__DIR__.'/../models/*.php') as $file)
{
	$class = 'MyNamespace\\Models\\'.substr(basename($file), 0, -4);
	if ($class === 'MyNamespace\\Models\\Model' || $class === 'MyNamespace\\Models\\Promotion')
	{
		continue;
	}
	include $file;
	$files++;
}
echo ($time + microtime(true)) * 1000, ' - files: '.$files;

=> for 120 files
=> first load: about 120ms
=> next loads: 4-8ms (opcache must play a part here)

$time = -1 * microtime(true);
$loader = new Loader();
$loader->registerNamespaces([
	'MyNamespace\Controllers' => __DIR__.'/controllers/',
	'MyNamespace\Backend\Controllers' => __DIR__.'/../backend/controllers/',
	'MyNamespace\Frontend\Controllers' => __DIR__.'/../frontend/controllers/',
	'MyNamespace\Models' => __DIR__.'/../models/',
	'MyNamespace\Library' => __DIR__.'/../library/',
	'MyNamespace\Plugins' => __DIR__.'/../plugins/',
]);
$loader->register();
echo ($time + microtime(true)) * 1000;

=> takes less than a millisecond as expected

$time = -1 * microtime(true);
$files = 2;
foreach (glob(__DIR__.'/../models/*.php') as $file)
{
	$class = 'MyNamespace\\Models\\'.substr(basename($file), 0, -4);
	class_exists($class);
	$files++;
}
echo ($time + microtime(true)) * 1000, ' - files: '.$files;

=> for 121 files
=> first load: 250ms
=> next loads: 100-150ms (about 1ms per loaded class)

The culprit is the is_file() test before including the class: https://github.com/phalcon/cphalcon/blob/v3.3.2/phalcon/loader.zep#L368

Proposed fix

Add a parameter, either as a new function (setFileChecking) or as a third parameter in registerNamespaces() (see https://github.com/phalcon/cphalcon/blob/v3.3.2/phalcon/loader.zep#L109), for example $this->fileChecking:

• default => is_file()
• stream => stream_resolve_include_path() (as it seems to be really faster than is_file(), but implies some issues if the file is removed from the filesystem)
• none => no file check (you should always have a class file if you load one class, don't you? It's true only if you don't use multiple directories for the same namespace)

Details

• Phalcon version: 3.3.2
• PHP Version: 7.0.27
• Operating System: Linux Debian stable
• Installation type: installing via package manager
• Zephir version (if any): (from package) 0.10.7
• Server: Lighttpd
• Other related info: none

[dugwood]

@sergeyklay

[dugwood]

Waiting for PR #13361 to be merged to close this one. PR is working great (and opcache is really important in the end).