ACM/lib/Psr4AutoloaderClass.php

<?php

/*
PSR-4 autoloader example implementations given by
https://www.php-fig.org/psr/psr-4/
*/

namespace Module\ACM\Lib;

/**
 * An example of a general-purpose implementation that includes the optional
 * functionality of allowing multiple base directories for a single namespace
 * prefix.
 *
 * Given a foo-bar package of classes in the file system at the following
 * paths ...
 *
 *     /path/to/packages/foo-bar/
 *         src/
 *             Baz.php             # Foo\Bar\Baz
 *             Qux/
 *                 Quux.php        # Foo\Bar\Qux\Quux
 *         tests/
 *             BazTest.php         # Foo\Bar\BazTest
 *             Qux/
 *                 QuuxTest.php    # Foo\Bar\Qux\QuuxTest
 *
 * ... add the path to the classe files for the \Foo\Bar\ namespace prefix
 * as follows:
 *
 *      <?php
 *      // instantiate the loader
 *      $loader = new \Example\Psr4AutoloaderClass;
 *
 *      // register the autoloader
 *      $loader->register();
 *
 *      // register the base directories for the namespace prefix
 *      $loader->addNamespace('Foo\Bar', '/path/to/packages/foo-bar/src');
 *      $loader->addNamespace('Foo\Bar', '/path/to/packages/foo-bar/tests');
 *
 * The following line would cause the autoloader to attempt to load the
 * \Foo\Bar\Qux\Quux classe from /path/to/packages/foo-bar/src/Qux/Quux.php:
 *
 *      <?php
 *      new \Foo\Bar\Qux\Quux;
 *
 * The following line would cause the autoloader to attempt to load the
 * \Foo\Bar\Qux\QuuxTest classe from /path/to/packages/foo-bar/tests/Qux/QuuxTest.php:
 *
 *      <?php
 *      new \Foo\Bar\Qux\QuuxTest;
 */
class Psr4AutoloaderClass
{

    private bool $debug;

    public function __construct(bool $debug=false)
    {
        $this->debug = $debug;
    }

    private function affichageDebogage(string $message) : void
    {
        if ($this->debug)
            echo $message;
    }

    /**
     * An associative array where the key is a namespace prefix and the value
     * is an array of base directories for classes in that namespace.
     *
     * @var array
     */
    protected array $prefixes = array();

    /**
     * Register loader with SPL autoloader stack.
     *
     * @return void
     */
    public function register() : void
    {
        spl_autoload_register(array($this, 'loadClass'));
    }

    /**
     * Adds a base directory for a namespace prefix.
     *
     * @param string $prefix The namespace prefix.
     * @param string $base_dir A base directory for classe files in the
     * namespace.
     * @param bool $prepend If true, prepend the base directory to the stack
     * instead of appending it; this causes it to be searched first rather
     * than last.
     * @return void
     */
    public function addNamespace(string $prefix, string $base_dir, bool $prepend = false) : void
    {
        // normalize namespace prefix
        $prefix = trim($prefix, '\\') . '\\';

        // normalize the base directory with a trailing separator
        $base_dir = rtrim($base_dir, DIRECTORY_SEPARATOR) . '/';

        // initialize the namespace prefix array
        if (isset($this->prefixes[$prefix]) === false) {
            $this->prefixes[$prefix] = array();
        }

        // retain the base directory for the namespace prefix
        if ($prepend) {
            array_unshift($this->prefixes[$prefix], $base_dir);
        } else {
            array_push($this->prefixes[$prefix], $base_dir);
        }
    }

    /**
     * Loads the classe file for a given classe name.
     *
     * @param string $class The fully-qualified classe name.
     * @return mixed The mapped file name on success, or boolean false on
     * failure.
     */
    public function loadClass(string $class)
    {
        $this->affichageDebogage("<h3>Chargement automatique de classe $class </h3>");
        // the current namespace prefix
        $prefix = $class;

        // work backwards through the namespace names of the fully-qualified
        // classe name to find a mapped file name
        while (false !== $pos = strrpos($prefix, '\\')) {

            // retain the trailing namespace separator in the prefix
            $prefix = substr($class, 0, $pos + 1);

            // the rest is the relative classe name
            $relative_class = substr($class, $pos + 1);

            // try to load a mapped file for the prefix and relative classe
            $mapped_file = $this->loadMappedFile($prefix, $relative_class);
            if ($mapped_file) {
                return $mapped_file;
            }

            // remove the trailing namespace separator for the next iteration
            // of strrpos()
            $prefix = rtrim($prefix, '\\');
        }

        // never found a mapped file
        $this->affichageDebogage("<h3 style=\"color:red;font-weight: bold;\">Échec !</h3>");
        return false;
    }

    /**
     * Load the mapped file for a namespace prefix and relative classe.
     *
     * @param string $prefix The namespace prefix.
     * @param string $relative_class The relative classe name.
     * @return mixed Boolean false if no mapped file can be loaded, or the
     * name of the mapped file that was loaded.
     */
    protected function loadMappedFile(string $prefix, string $relative_class)
    {
        // are there any base directories for this namespace prefix?
        if (isset($this->prefixes[$prefix]) === false) {
            return false;
        }

        // look through base directories for this namespace prefix
        foreach ($this->prefixes[$prefix] as $base_dir) {

            $this->affichageDebogage("Remplacement du préfixe $prefix par $base_dir<br>");

            // replace the namespace prefix with the base directory,
            // replace namespace separators with directory separators
            // in the relative classe name, append with .php
            $file = $base_dir
                . str_replace('\\', '/', $relative_class)
                . '.php';

            // if the mapped file exists, require it
            if ($this->requireFile($file)) {
                // yes, we're done
                return $file;
            }
        }

        // never found it
        return false;
    }

    /**
     * If a file exists, require it from the file system.
     *
     * @param string $file The file to require.
     * @return bool True if the file exists, false if not.
     */
    protected function requireFile(string $file) : bool
    {
        if (file_exists($file)) {
            $this->affichageDebogage("<p><span style=\"color:green;font-weight: bold;\">Réussite</span> : fichier chargé <pre>$file</pre></p>");
            require $file;
            return true;
        }
        $this->affichageDebogage("<p><span style=\"color:red;font-weight: bold;\">Échec</span> : fichier introuvable <pre>$file</pre></p>");
        return false;
    }
}