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

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+<?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.
+ */
+
+/**
+ * Class TemplateVariableViewHelperTrait
+ *
+ * Trait implementable by ViewHelpers which operate with
+ * template variables in one way or another. Contains
+ * the following main responsibilities:
+ *
+ * - A generic "as" argument solution
+ * - A method to render child content with automatically
+ *   backed up variables specified in an array.
+ */
+trait TemplateVariableViewHelperTrait {
+
+	/**
+	 * Default initialisation of arguments - will be used
+	 * if the implementing ViewHelper does not itself define
+	 * this method. The default behavior is to only register
+	 * the "as" argument.
+	 *
+	 * @return void
+	 */
+	public function initializeArguments() {
+		$this->registerAsArgument();
+	}
+
+	/**
+	 * Registers the "as" argument for use with the
+	 * implementing ViewHelper.
+	 *
+	 * @return void
+	 */
+	protected function registerAsArgument() {
+		$this->registerArgument('as', 'string', 'Template variable name to assign; if not specified the ViewHelper returns the variable instead.');
+	}
+
+	/**
+	 * @return mixed
+	 */
+	protected function renderChildrenWithVariableOrReturnInput($variable = NULL) {
+		$as = $this->arguments['as'];
+		if (TRUE === empty($as)) {
+			return $variable;
+		} else {
+			$variables = array($as => $variable);
+			$content = static::renderChildrenWithVariables($variables);
+		}
+		return $content;
+	}
+
+	/**
+	 * @param \TYPO3\CMS\Fluid\Core\Rendering\RenderingContextInterface $renderingContext
+	 * @param \Closure $renderChildrenClosure
+	 * @return mixed
+	 */
+	protected static function renderChildrenWithVariableOrReturnInputStatic($variable = NULL, $as, $renderingContext = NULL, $renderChildrenClosure = NULL) {
+		if (TRUE === empty($as)) {
+			return $variable;
+		} else {
+			$variables = array($as => $variable);
+			$content = static::renderChildrenWithVariablesStatic($variables, $renderingContext->getTemplateVariableContainer(), $renderChildrenClosure);
+		}
+		return $content;
+	}
+
+	/**
+	 * Renders tag content of ViewHelper and inserts variables
+	 * in $variables into $variableContainer while keeping backups
+	 * of each existing variable, restoring it after rendering.
+	 * Returns the output of the renderChildren() method on $viewHelper.
+	 *
+	 * @param array $variables
+	 * @return mixed
+	 */
+	protected function renderChildrenWithVariables(array $variables) {
+		return self::renderChildrenWithVariablesStatic($variables, $this->templateVariableContainer, $this->buildRenderChildrenClosure());
+	}
+
+	/**
+	 * Renders tag content of ViewHelper and inserts variables
+	 * in $variables into $variableContainer while keeping backups
+	 * of each existing variable, restoring it after rendering.
+	 * Returns the output of the renderChildren() method on $viewHelper.
+	 *
+	 * @param array $variables
+	 * @param \TYPO3\CMS\Fluid\Core\ViewHelper\TemplateVariableContainer $templateVariableContainer
+	 * @param \Closure $renderChildrenClosure
+	 * @return mixed
+	 */
+	protected static function renderChildrenWithVariablesStatic(array $variables, $templateVariableContainer, $renderChildrenClosure) {
+		$backups = self::backupVariables($variables, $templateVariableContainer);
+		$content = $renderChildrenClosure();
+		self::restoreVariables($variables, $backups, $templateVariableContainer);
+		return $content;
+	}
+
+	/**
+	 * @param array $variables
+	 * @param \TYPO3\CMS\Fluid\Core\ViewHelper\TemplateVariableContainer $templateVariableContainer
+	 * @param \Closure $renderChildrenClosure
+	 * @return array
+	 */
+	private static function backupVariables(array $variables, $templateVariableContainer) {
+		$backups = array();
+		foreach ($variables as $variableName => $variableValue) {
+			if (TRUE === $templateVariableContainer->exists($variableName)) {
+				$backups[$variableName] = $templateVariableContainer->get($variableName);
+				$templateVariableContainer->remove($variableName);
+			}
+			$templateVariableContainer->add($variableName, $variableValue);
+		}
+		return $backups;
+	}
+
+	/**
+	 * @param array $variables
+	 * @param array $backups
+	 * @param \TYPO3\CMS\Fluid\Core\ViewHelper\TemplateVariableContainer $templateVariableContainer
+	 * @return void
+	 */
+	private static function restoreVariables(array $variables, array $backups, $templateVariableContainer) {
+		foreach ($variables as $variableName => $variableValue) {
+			$templateVariableContainer->remove($variableName);
+			if (TRUE === isset($backups[$variableName])) {
+				$templateVariableContainer->add($variableName, $variableValue);
+			}
+		}
+	}
+
+}