View Cleaning (#17018)

This cleans up the view component and extracts some traits.

src/Illuminate/View/Compilers/Concerns/CompilesLayouts.php

@@ -6,6 +6,13 @@
 
 trait CompilesLayouts
 {
+    /**
+     * The name of the last section that was started.
+     *
+     * @var string
+     */
+    protected $lastSection;
+
     /**
      * Compile the extends statements into valid PHP.
      *
@@ -31,6 +38,8 @@ protected function compileExtends($expression)
      */
     protected function compileSection($expression)
     {
+        $this->lastSection = trim($expression, "()'");
+
         return "<?php \$__env->startSection{$expression}; ?>";
     }
 
@@ -41,7 +50,7 @@ protected function compileSection($expression)
      */
     protected function compileParent()
     {
-        return ViewFactory::parentPlaceholder();
+        return ViewFactory::parentPlaceholder($this->lastSection ?: '');
     }
 
     /**

src/Illuminate/View/Compilers/Concerns/CompilesLoops.php

@@ -22,7 +22,7 @@ protected function compileForelse($expression)
 
         $initLoop = "\$__currentLoopData = {$iteratee}; \$__env->addLoop(\$__currentLoopData);";
 
-        $iterateLoop = '$__env->incrementLoopIndices(); $loop = $__env->getFirstLoop();';
+        $iterateLoop = '$__env->incrementLoopIndices(); $loop = $__env->getLastLoop();';
 
         return "<?php {$empty} = true; {$initLoop} foreach(\$__currentLoopData as {$iteration}): {$iterateLoop} {$empty} = false; ?>";
     }
@@ -37,7 +37,7 @@ protected function compileEmpty($expression)
     {
         $empty = '$__empty_'.$this->forElseCounter--;
 
-        return "<?php endforeach; \$__env->popLoop(); \$loop = \$__env->getFirstLoop(); if ({$empty}): ?>";
+        return "<?php endforeach; \$__env->popLoop(); \$loop = \$__env->getLastLoop(); if ({$empty}): ?>";
     }
 
     /**
@@ -78,7 +78,7 @@ protected function compileForeach($expression)
 
         $initLoop = "\$__currentLoopData = {$iteratee}; \$__env->addLoop(\$__currentLoopData);";
 
-        $iterateLoop = '$__env->incrementLoopIndices(); $loop = $__env->getFirstLoop();';
+        $iterateLoop = '$__env->incrementLoopIndices(); $loop = $__env->getLastLoop();';
 
         return "<?php {$initLoop} foreach(\$__currentLoopData as {$iteration}): {$iterateLoop} ?>";
     }
@@ -124,7 +124,7 @@ protected function compileEndfor($expression)
      */
     protected function compileEndforeach($expression)
     {
-        return '<?php endforeach; $__env->popLoop(); $loop = $__env->getFirstLoop(); ?>';
+        return '<?php endforeach; $__env->popLoop(); $loop = $__env->getLastLoop(); ?>';
     }
 
     /**

src/Illuminate/View/Concerns/ManagesComponents.php

@@ -0,0 +1,123 @@
+<?php
+
+namespace Illuminate\View\Concerns;
+
+use Illuminate\Support\HtmlString;
+
+trait ManagesComponents
+{
+    /**
+     * The components being rendered.
+     *
+     * @var array
+     */
+    protected $componentStack = [];
+
+    /**
+     * The original data passed to the component.
+     *
+     * @var array
+     */
+    protected $componentData = [];
+
+    /**
+     * The slot contents for the component.
+     *
+     * @var array
+     */
+    protected $slots = [];
+
+    /**
+     * The names of the slots being rendered.
+     *
+     * @var array
+     */
+    protected $slotStack = [];
+
+    /**
+     * Start a component rendering process.
+     *
+     * @param  string  $name
+     * @param  array  $data
+     * @return void
+     */
+    public function startComponent($name, array $data = [])
+    {
+        if (ob_start()) {
+            $this->componentStack[] = $name;
+
+            $this->componentData[$name] = $data;
+
+            $this->slots[$name] = [];
+        }
+    }
+
+    /**
+     * Render the current component.
+     *
+     * @return string
+     */
+    public function renderComponent()
+    {
+        $name = array_pop($this->componentStack);
+
+        return tap($this->make($name, $this->componentData($name))->render(), function () use ($name) {
+            $this->resetComponent($name);
+        });
+    }
+
+    /**
+     * Get the data for the given component.
+     *
+     * @param  string  $name
+     * @return array
+     */
+    protected function componentData($name)
+    {
+        $slot = ['slot' => new HtmlString(trim(ob_get_clean()))];
+
+        return array_merge($this->componentData[$name], $slot, $this->slots[$name]);
+    }
+
+    /**
+     * Start the slot rendering process.
+     *
+     * @param  string  $name
+     * @return void
+     */
+    public function slot($name)
+    {
+        if (ob_start()) {
+            $this->slots[last($this->componentStack)][$name] = '';
+
+            $this->slotStack[last($this->componentStack)][] = $name;
+        }
+    }
+
+    /**
+     * Save the slot content for rendering.
+     *
+     * @return void
+     */
+    public function endSlot()
+    {
+        $current = last($this->componentStack);
+
+        $currentSlot = array_pop($this->slotStack[$current]);
+
+        $this->slots[$current][$currentSlot] = new HtmlString(trim(ob_get_clean()));
+    }
+
+    /**
+     * Reset the state for the given component.
+     *
+     * @param  string  $name
+     * @return void
+     */
+    protected function resetComponent($name)
+    {
+        unset($this->slots[$name]);
+        unset($this->slotStack[$name]);
+        unset($this->componentData[$name]);
+    }
+}

src/Illuminate/View/Concerns/ManagesEvents.php

@@ -0,0 +1,200 @@
+<?php
+
+namespace Illuminate\View\Concerns;
+
+use Closure;
+use Illuminate\Support\Str;
+use Illuminate\Contracts\Events\Dispatcher;
+use Illuminate\Contracts\Container\Container;
+use Illuminate\Contracts\View\View as ViewContract;
+
+trait ManagesEvents
+{
+    /**
+     * Register a view creator event.
+     *
+     * @param  array|string     $views
+     * @param  \Closure|string  $callback
+     * @return array
+     */
+    public function creator($views, $callback)
+    {
+        $creators = [];
+
+        foreach ((array) $views as $view) {
+            $creators[] = $this->addViewEvent($view, $callback, 'creating: ');
+        }
+
+        return $creators;
+    }
+
+    /**
+     * Register multiple view composers via an array.
+     *
+     * @param  array  $composers
+     * @return array
+     */
+    public function composers(array $composers)
+    {
+        $registered = [];
+
+        foreach ($composers as $callback => $views) {
+            $registered = array_merge($registered, $this->composer($views, $callback));
+        }
+
+        return $registered;
+    }
+
+    /**
+     * Register a view composer event.
+     *
+     * @param  array|string  $views
+     * @param  \Closure|string  $callback
+     * @param  int|null  $priority
+     * @return array
+     */
+    public function composer($views, $callback, $priority = null)
+    {
+        $composers = [];
+
+        foreach ((array) $views as $view) {
+            $composers[] = $this->addViewEvent($view, $callback, 'composing: ', $priority);
+        }
+
+        return $composers;
+    }
+
+    /**
+     * Add an event for a given view.
+     *
+     * @param  string  $view
+     * @param  \Closure|string  $callback
+     * @param  string  $prefix
+     * @param  int|null  $priority
+     * @return \Closure|null
+     */
+    protected function addViewEvent($view, $callback, $prefix = 'composing: ', $priority = null)
+    {
+        $view = $this->normalizeName($view);
+
+        if ($callback instanceof Closure) {
+            $this->addEventListener($prefix.$view, $callback, $priority);
+
+            return $callback;
+        } elseif (is_string($callback)) {
+            return $this->addClassEvent($view, $callback, $prefix, $priority);
+        }
+    }
+
+    /**
+     * Register a class based view composer.
+     *
+     * @param  string    $view
+     * @param  string    $class
+     * @param  string    $prefix
+     * @param  int|null  $priority
+     * @return \Closure
+     */
+    protected function addClassEvent($view, $class, $prefix, $priority = null)
+    {
+        $name = $prefix.$view;
+
+        // When registering a class based view "composer", we will simply resolve the
+        // classes from the application IoC container then call the compose method
+        // on the instance. This allows for convenient, testable view composers.
+        $callback = $this->buildClassEventCallback(
+            $class, $prefix
+        );
+
+        $this->addEventListener($name, $callback, $priority);
+
+        return $callback;
+    }
+
+    /**
+     * Build a class based container callback Closure.
+     *
+     * @param  string  $class
+     * @param  string  $prefix
+     * @return \Closure
+     */
+    protected function buildClassEventCallback($class, $prefix)
+    {
+        list($class, $method) = $this->parseClassEvent($class, $prefix);
+
+        // Once we have the class and method name, we can build the Closure to resolve
+        // the instance out of the IoC container and call the method on it with the
+        // given arguments that are passed to the Closure as the composer's data.
+        return function () use ($class, $method) {
+            return call_user_func_array(
+                [$this->container->make($class), $method], func_get_args()
+            );
+        };
+    }
+
+    /**
+     * Parse a class based composer name.
+     *
+     * @param  string  $class
+     * @param  string  $prefix
+     * @return array
+     */
+    protected function parseClassEvent($class, $prefix)
+    {
+        if (! Str::contains($class, '@')) {
+            return [$class, $this->classEventMethodForPrefix($prefix)];
+        }
+
+        return explode('@', $class);
+    }
+
+    /**
+     * Determine the class event method based on the given prefix.
+     *
+     * @param  string  $prefix
+     * @return string
+     */
+    protected function classEventMethodForPrefix($prefix)
+    {
+        return Str::contains($prefix, 'composing') ? 'compose' : 'create';
+    }
+
+    /**
+     * Add a listener to the event dispatcher.
+     *
+     * @param  string    $name
+     * @param  \Closure  $callback
+     * @param  int|null  $priority
+     * @return void
+     */
+    protected function addEventListener($name, $callback, $priority = null)
+    {
+        if (is_null($priority)) {
+            $this->events->listen($name, $callback);
+        } else {
+            $this->events->listen($name, $callback, $priority);
+        }
+    }
+
+    /**
+     * Call the composer for a given view.
+     *
+     * @param  \Illuminate\Contracts\View\View  $view
+     * @return void
+     */
+    public function callComposer(ViewContract $view)
+    {
+        $this->events->fire('composing: '.$view->name(), [$view]);
+    }
+
+    /**
+     * Call the creator for a given view.
+     *
+     * @param  \Illuminate\Contracts\View\View  $view
+     * @return void
+     */
+    public function callCreator(ViewContract $view)
+    {
+        $this->events->fire('creating: '.$view->name(), [$view]);
+    }
+}