AliasLoader.php

TLDR

This file defines the AliasLoader class in the Illuminate\Foundation namespace. It is responsible for loading class aliases and real-time facades in Laravel applications.

Methods

__construct

The constructor method creates a new AliasLoader instance with the given array of class aliases.

getInstance

This method gets or creates the singleton alias loader instance. The method takes an optional array of aliases as an argument and merges them with the existing aliases.

load

The load method is responsible for loading a class alias if it is registered. It checks if the alias belongs to the facade namespace and loads the facade if it does. If the alias exists in the aliases array, it registers the class alias.

loadFacade

This protected method is used to load a real-time facade for the given alias. It requires the file that contains the facade implementation.

ensureFacadeExists

This protected method ensures that the given alias has an existing real-time facade class. If the facade file does not exist, it creates a new one based on the facade stub.

formatFacadeStub

This protected method formats the facade stub with the proper namespace and class. It replaces placeholders in the stub with the actual values.

alias

This method adds an alias to the loader. It takes the alias and the class as arguments.

register

The register method is responsible for registering the loader on the auto-loader stack.

prependToLoaderStack

This protected method prepends the load method to the auto-loader stack. It is called by the register method.

getAliases

This method returns the registered aliases.

setAliases

This method sets the registered aliases.

isRegistered

This method returns true if the loader has been registered.

setRegistered

This method sets the "registered" state of the loader.

setFacadeNamespace

This static method sets the real-time facade namespace.

setInstance

This static method sets the value of the singleton alias loader.

__clone

The __clone method is a private method used to prevent cloning of the object.

<?php

namespace Illuminate\Foundation;

class AliasLoader
{
    /**
     * The array of class aliases.
     *
     * @var array
     */
    protected $aliases;

    /**
     * Indicates if a loader has been registered.
     *
     * @var bool
     */
    protected $registered = false;

    /**
     * The namespace for all real-time facades.
     *
     * @var string
     */
    protected static $facadeNamespace = 'Facades\\';

    /**
     * The singleton instance of the loader.
     *
     * @var \Illuminate\Foundation\AliasLoader
     */
    protected static $instance;

    /**
     * Create a new AliasLoader instance.
     *
     * @param  array  $aliases
     * @return void
     */
    private function __construct($aliases)
    {
        $this->aliases = $aliases;
    }

    /**
     * Get or create the singleton alias loader instance.
     *
     * @param  array  $aliases
     * @return \Illuminate\Foundation\AliasLoader
     */
    public static function getInstance(array $aliases = [])
    {
        if (is_null(static::$instance)) {
            return static::$instance = new static($aliases);
        }

        $aliases = array_merge(static::$instance->getAliases(), $aliases);

        static::$instance->setAliases($aliases);

        return static::$instance;
    }

    /**
     * Load a class alias if it is registered.
     *
     * @param  string  $alias
     * @return bool|null
     */
    public function load($alias)
    {
        if (static::$facadeNamespace && str_starts_with($alias, static::$facadeNamespace)) {
            $this->loadFacade($alias);

            return true;
        }

        if (isset($this->aliases[$alias])) {
            return class_alias($this->aliases[$alias], $alias);
        }
    }

    /**
     * Load a real-time facade for the given alias.
     *
     * @param  string  $alias
     * @return void
     */
    protected function loadFacade($alias)
    {
        require $this->ensureFacadeExists($alias);
    }

    /**
     * Ensure that the given alias has an existing real-time facade class.
     *
     * @param  string  $alias
     * @return string
     */
    protected function ensureFacadeExists($alias)
    {
        if (is_file($path = storage_path('framework/cache/facade-'.sha1($alias).'.php'))) {
            return $path;
        }

        file_put_contents($path, $this->formatFacadeStub(
            $alias, file_get_contents(__DIR__.'/stubs/facade.stub')
        ));

        return $path;
    }

    /**
     * Format the facade stub with the proper namespace and class.
     *
     * @param  string  $alias
     * @param  string  $stub
     * @return string
     */
    protected function formatFacadeStub($alias, $stub)
    {
        $replacements = [
            str_replace('/', '\\', dirname(str_replace('\\', '/', $alias))),
            class_basename($alias),
            substr($alias, strlen(static::$facadeNamespace)),
        ];

        return str_replace(
            ['DummyNamespace', 'DummyClass', 'DummyTarget'], $replacements, $stub
        );
    }

    /**
     * Add an alias to the loader.
     *
     * @param  string  $alias
     * @param  string  $class
     * @return void
     */
    public function alias($alias, $class)
    {
        $this->aliases[$alias] = $class;
    }

    /**
     * Register the loader on the auto-loader stack.
     *
     * @return void
     */
    public function register()
    {
        if (! $this->registered) {
            $this->prependToLoaderStack();

            $this->registered = true;
        }
    }

    /**
     * Prepend the load method to the auto-loader stack.
     *
     * @return void
     */
    protected function prependToLoaderStack()
    {
        spl_autoload_register([$this, 'load'], true, true);
    }

    /**
     * Get the registered aliases.
     *
     * @return array
     */
    public function getAliases()
    {
        return $this->aliases;
    }

    /**
     * Set the registered aliases.
     *
     * @param  array  $aliases
     * @return void
     */
    public function setAliases(array $aliases)
    {
        $this->aliases = $aliases;
    }

    /**
     * Indicates if the loader has been registered.
     *
     * @return bool
     */
    public function isRegistered()
    {
        return $this->registered;
    }

    /**
     * Set the "registered" state of the loader.
     *
     * @param  bool  $value
     * @return void
     */
    public function setRegistered($value)
    {
        $this->registered = $value;
    }

    /**
     * Set the real-time facade namespace.
     *
     * @param  string  $namespace
     * @return void
     */
    public static function setFacadeNamespace($namespace)
    {
        static::$facadeNamespace = rtrim($namespace, '\\').'\\';
    }

    /**
     * Set the value of the singleton alias loader.
     *
     * @param  \Illuminate\Foundation\AliasLoader  $loader
     * @return void
     */
    public static function setInstance($loader)
    {
        static::$instance = $loader;
    }

    /**
     * Clone method.
     *
     * @return void
     */
    private function __clone()
    {
        //
    }
}