<?php namespace EmailLog;
/**
* Autoloader for EmailLog, based on the PSR-4 general purpose implementation.
*
* @see http://www.php-fig.org/psr/psr-4/
*
* This differs from WordPress coding standard in the following ways.
*
* - Class name and directory names use Snake case.
* - Use of namespaces.
*
* 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 class files for the \Foo\Bar\ namespace prefix
* as follows:
*
* <?php
* // instantiate the loader
* $loader = new \EmailLog\EmailLogAutoloader;
*
* // 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 class 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 class from /path/to/packages/foo-bar/tests/Qux/QuuxTest.php:
*
* <?php
* new \Foo\Bar\Qux\QuuxTest;
* @since 2.0
*/
class EmailLogAutoloader {
/**
* 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();
/**
* An associative array containing the list files that needs to be autoloaded.
*
* @var array
*/
protected $files = array();
/**
* Register loader with SPL autoloader stack.
*
* @return void
*/
public function register() {
spl_autoload_register( array( $this, 'load_class' ) );
// file exists check is already done in `add_file`.
foreach ( $this->files as $file ) {
$this->require_file( $file );
}
}
/**
* Adds a base directory for a namespace prefix.
*
* @param string $prefix The namespace prefix.
* @param string $base_dir 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 add_namespace( $prefix, $base_dir, $prepend = false ) {
// 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 ( false === isset( $this->prefixes[ $prefix ] ) ) {
$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 );
}
}
/**
* Add a file to be autoloaded.
*
* @param string $filename File to be autoloaded.
*/
public function add_file( $filename ) {
if ( ! in_array( $filename, $this->files, true ) ) {
$this->files[] = $filename;
}
}
/**
* Loads the class file for a given class name.
*
* @param string $class The fully-qualified class name.
*
* @return false|string The mapped file name on success, or boolean false on
* failure.
*/
public function load_class( $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
$relative_class = substr( $class, $pos + 1 );
// try to load a mapped file for the prefix and relative class
$mapped_file = $this->load_mapped_file( $prefix, $relative_class );
if ( $mapped_file !== false ) {
return $mapped_file;
}
// 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 $relative_class The relative class name.
*
* @return false|string Boolean false if no mapped file can be loaded, or the
* name of the mapped file that was loaded.
*/
protected function load_mapped_file( $prefix, $relative_class ) {
// are there any base directories for this namespace prefix?
if ( false === isset( $this->prefixes[ $prefix ] ) ) {
return false;
}
// look through base directories for this namespace prefix
foreach ( $this->prefixes[ $prefix ] as $base_dir ) {
// replace the namespace prefix with the base directory,
// replace namespace separators with directory separators
// in the relative class name, append with .php
$file = $base_dir
. str_replace( '\\', '/', $relative_class )
. '.php';
// if the mapped file exists, require it
if ( $this->require_file( $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 require_file( $file ) {
if ( file_exists( $file ) ) {
require_once $file;
return true;
}
return false;
}
}