zentaopms/lib/spout/Autoloader/Psr4Autoloader.php
2023-05-16 10:47:08 +08:00

151 lines
4.5 KiB
PHP

<?php
namespace Box\Spout\Autoloader;
/**
* Class Psr4Autoloader
* @see https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-4-autoloader-examples.md#class-example
*
* @package Box\Spout\Autoloader
*/
class Psr4Autoloader
{
/**
* 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 $prefixes = array();
/**
* Register loader with SPL autoloader stack.
*
* @return void
*/
public function register()
{
spl_autoload_register(array($this, 'loadClass'));
}
/**
* Adds a base directory for a namespace prefix.
*
* @param string $prefix The namespace prefix.
* @param string $baseDir A base directory for class files in the
* namespace.
* @param bool $prepend If true, prepend the base directory to the stack
* instead of appending it; this causes it to be searched first rather
* than last.
* @return void
*/
public function addNamespace($prefix, $baseDir, $prepend = false)
{
// normalize namespace prefix
$prefix = trim($prefix, '\\') . '\\';
// normalize the base directory with a trailing separator
$baseDir = rtrim($baseDir, 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], $baseDir);
} else {
array_push($this->prefixes[$prefix], $baseDir);
}
}
/**
* Loads the class file for a given class name.
*
* @param string $class The fully-qualified class name.
* @return mixed The mapped file name on success, or boolean false on
* failure.
*/
public function loadClass($class)
{
// the current namespace prefix
$prefix = $class;
// work backwards through the namespace names of the fully-qualified
// class 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 class name
$relativeClass = substr($class, $pos + 1);
// try to load a mapped file for the prefix and relative class
$mappedFile = $this->loadMappedFile($prefix, $relativeClass);
if ($mappedFile !== false) {
return $mappedFile;
}
// remove the trailing namespace separator for the next iteration
// of strrpos()
$prefix = rtrim($prefix, '\\');
}
// never found a mapped file
return false;
}
/**
* Load the mapped file for a namespace prefix and relative class.
*
* @param string $prefix The namespace prefix.
* @param string $relativeClass The relative class name.
* @return mixed Boolean false if no mapped file can be loaded, or the
* name of the mapped file that was loaded.
*/
protected function loadMappedFile($prefix, $relativeClass)
{
// are there any base directories for this namespace prefix?
if (isset($this->prefixes[$prefix]) === false) {
return false;
}
// look through base directories for this namespace prefix
foreach ($this->prefixes[$prefix] as $baseDir) {
// replace the namespace prefix with the base directory,
// replace namespace separators with directory separators
// in the relative class name, append with .php
$file = $baseDir
. str_replace('\\', '/', $relativeClass)
. '.php';
// if the mapped file exists, require it
if ($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 $file The file to require.
* @return bool True if the file exists, false if not.
*/
protected function requireFile($file)
{
if (file_exists($file)) {
require $file;
return true;
}
return false;
}
}