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<?php
namespace Illuminate\Pipeline;
use Closure;
use RuntimeException;
use Illuminate\Contracts\Container\Container;
use Illuminate\Contracts\Pipeline\Pipeline as PipelineContract;
class Pipeline implements PipelineContract
{
/**
* The container implementation.
*
* @var \Illuminate\Contracts\Container\Container
*/
protected $container;
/**
* The object being passed through the pipeline.
*
* @var mixed
*/
protected $passable;
/**
* The array of class pipes.
*
* @var array
*/
protected $pipes = [];
/**
* The method to call on each pipe.
*
* @var string
*/
protected $method = 'handle';
/**
* Create a new class instance.
*
* @param \Illuminate\Contracts\Container\Container|null $container
* @return void
*/
public function __construct(Container $container = null)
{
$this->container = $container;
}
/**
* Set the object being sent through the pipeline.
*
* @param mixed $passable
* @return $this
*/
public function send($passable)
{
$this->passable = $passable;
return $this;
}
/**
* Set the array of pipes.
*
* @param array|mixed $pipes
* @return $this
*/
public function through($pipes)
{
$this->pipes = is_array($pipes) ? $pipes : func_get_args();
return $this;
}
/**
* Set the method to call on the pipes.
*
* @param string $method
* @return $this
*/
public function via($method)
{
$this->method = $method;
return $this;
}
/**
* Run the pipeline with a final destination callback.
*
* @param \Closure $destination
* @return mixed
*/
public function then(Closure $destination)
{
$pipeline = array_reduce(
array_reverse($this->pipes), $this->carry(), $this->prepareDestination($destination)
);
return $pipeline($this->passable);
}
/**
* Get the final piece of the Closure onion.
*
* @param \Closure $destination
* @return \Closure
*/
protected function prepareDestination(Closure $destination)
{
return function ($passable) use ($destination) {
return $destination($passable);
};
}
/**
* Get a Closure that represents a slice of the application onion.
*
* @return \Closure
*/
protected function carry()
{
return function ($stack, $pipe) {
return function ($passable) use ($stack, $pipe) {
if (is_callable($pipe)) {
// If the pipe is an instance of a Closure, we will just call it directly but
// otherwise we'll resolve the pipes out of the container and call it with
// the appropriate method and arguments, returning the results back out.
//如果pip也就中間件函式是一個閉包可呼叫函式，就直接回傳這個閉包函式就行了
//這里我還沒有找到對應的使用場景，后續補充
return $pipe($passable, $stack);
} elseif (! is_object($pipe)) {
list($name, $parameters) = $this->parsePipeString($pipe);
// If the pipe is a string we will parse the string and resolve the class out
// of the dependency injection container. We can then build a callable and
// execute the pipe function giving in the parameters that are required.
$pipe = $this->getContainer()->make($name);
$parameters = array_merge([$passable, $stack], $parameters);
} else {
// If the pipe is already an object we'll just make a callable and pass it to
// the pipe as-is. There is no need to do any extra parsing and formatting
// since the object we're given was already a fully instantiated object.
$parameters = [$passable, $stack];
}
return method_exists($pipe, $this->method)
? $pipe->{$this->method}(...$parameters)
: $pipe(...$parameters);
};
};
}
/**
* Parse full pipe string to get name and parameters.
*
* @param string $pipe
* @return array
*/
protected function parsePipeString($pipe)
{
list($name, $parameters) = array_pad(explode(':', $pipe, 2), 2, []);
if (is_string($parameters)) {
$parameters = explode(',', $parameters);
}
return [$name, $parameters];
}
/**
* Get the container instance.
*
* @return \Illuminate\Contracts\Container\Container
* @throws \RuntimeException
*/
protected function getContainer()
{
if (! $this->container) {
throw new RuntimeException('A container instance has not been passed to the Pipeline.');
}
return $this->container;
}
}
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