Initial commit

typo3conf/ext/vhs/Classes/Traits/ConditionViewHelperTrait.php

@@ -0,0 +1,132 @@
+<?php
+namespace FluidTYPO3\Vhs\Traits;
+
+/*
+ * This file is part of the FluidTYPO3/Vhs project under GPLv2 or later.
+ *
+ * For the full copyright and license information, please read the
+ * LICENSE.md file that was distributed with this source code.
+ */
+
+/**
+ * This trait can be used by viewhelpers that generate image tags
+ * to add srcsets based to the imagetag for better responsiveness
+ */
+trait ConditionViewHelperTrait {
+	/**
+	 * renders <f:then> child if $condition is true, otherwise renders <f:else> child.
+	 *
+	 * @return string the rendered string
+	 * @api
+	 */
+	public function render() {
+		if (static::evaluateCondition($this->arguments)) {
+			return $this->renderThenChild();
+		} else {
+			return $this->renderElseChild();
+		}
+	}
+
+	/**
+	 * Default implementation for use in compiled templates
+	 *
+	 * TODO: remove at some point, because this is only here for legacy reasons.
+	 * the AbstractConditionViewHelper in 6.2.* doesn't have a default render
+	 * method. 7.2+ on the other hand provides basically exactly this method here
+	 * luckily it's backwards compatible out of the box.
+	 * tl;dr -> remove after expiration of support for anything below 7.2
+	 *
+	 * @param array $arguments
+	 * @param \Closure $renderChildrenClosure
+	 * @param \TYPO3\CMS\Fluid\Core\Rendering\RenderingContextInterface $renderingContext
+	 * @return mixed
+	 */
+	static public function renderStatic(array $arguments, \Closure $renderChildrenClosure, \TYPO3\CMS\Fluid\Core\Rendering\RenderingContextInterface $renderingContext) {
+		$hasEvaluated = TRUE;
+		if (static::evaluateCondition($arguments)) {
+			$result = static::renderStaticThenChild($arguments, $hasEvaluated);
+			if ($hasEvaluated) {
+				return $result;
+			}
+
+			return $renderChildrenClosure();
+		} else {
+			$result = static::renderStaticElseChild($arguments, $hasEvaluated);
+			if ($hasEvaluated) {
+				return $result;
+			}
+		}
+
+		return '';
+	}
+
+	/**
+	 * Statically evalute "then" children.
+	 * The "$hasEvaluated" argument is there to distinguish the case that "then" returned NULL or was not evaluated.
+	 *
+	 * TODO: remove at some point, because this is only here for legacy reasons.
+	 * the AbstractConditionViewHelper in 6.2.* doesn't have a default render
+	 * method. 7.2+ on the other hand provides basically exactly this method here
+	 * luckily it's backwards compatible out of the box.
+	 * tl;dr -> remove after expiration of support for anything below 7.2
+	 *
+	 * @param array $arguments ViewHelper arguments
+	 * @param bool $hasEvaluated Can be used to check if the "then" child was actually evaluated by this method.
+	 * @return string
+	 */
+	static protected function renderStaticThenChild($arguments, &$hasEvaluated) {
+		if (isset($arguments['then'])) {
+			return $arguments['then'];
+		}
+		if (isset($arguments['__thenClosure'])) {
+			$thenClosure = $arguments['__thenClosure'];
+			return $thenClosure();
+		} elseif (isset($arguments['__elseClosure'])) {
+			return '';
+		}
+
+		$hasEvaluated = FALSE;
+	}
+
+	/**
+	 * Statically evalute "else" children.
+	 * The "$hasEvaluated" argument is there to distinguish the case that "else" returned NULL or was not evaluated.
+	 *
+	 * TODO: remove at some point, because this is only here for legacy reasons.
+	 * the AbstractConditionViewHelper in 6.2.* doesn't have a default render
+	 * method. 7.2+ on the other hand provides basically exactly this method here
+	 * luckily it's backwards compatible out of the box.
+	 * tl;dr -> remove after expiration of support for anything below 7.2
+	 *
+	 * @param array $arguments ViewHelper arguments
+	 * @param bool $hasEvaluated Can be used to check if the "else" child was actually evaluated by this method.
+	 * @return string
+	 */
+	static protected function renderStaticElseChild($arguments, &$hasEvaluated) {
+		if (isset($arguments['else'])) {
+			return $arguments['else'];
+		}
+		if (isset($arguments['__elseClosure'])) {
+			$elseClosure = $arguments['__elseClosure'];
+			return $elseClosure();
+		}
+
+		$hasEvaluated = FALSE;
+	}
+
+	/**
+	 * This method decides if the condition is TRUE or FALSE. It can be overriden in extending viewhelpers to adjust functionality.
+	 *
+	 * TODO: remove at some point, because this is only here for legacy reasons.
+	 * the AbstractConditionViewHelper in 6.2.* doesn't have a default render
+	 * method. 7.2+ on the other hand provides basically exactly this method here
+	 * luckily it's backwards compatible out of the box.
+	 * tl;dr -> remove after expiration of support for anything below 7.2
+	 *
+	 * @param array $arguments ViewHelper arguments to evaluate the condition for this ViewHelper, allows for flexiblity in overriding this method.
+	 * @return bool
+	 */
+	static protected function evaluateCondition($arguments = NULL) {
+		return (isset($arguments['condition']) && $arguments['condition']);
+	}
+}