Add once option to css().

The default value is false for backwards compatibility. In 3.0, the
default will be made consistent with script().

Refs #1973
Refs #3628

lib/Cake/Test/Case/View/Helper/HtmlHelperTest.php

@@ -695,6 +695,31 @@ public function testCssLink() {
 		$this->assertTags($result, $expected);
 	}
 
+/**
+ * Test css() with once option.
+ *
+ * @return void
+ */
+	public function testCssLinkOnce() {
+		Configure::write('Asset.filter.css', false);
+
+		$result = $this->Html->css('screen', array('once' => true));
+		$expected = array(
+			'link' => array('rel' => 'stylesheet', 'type' => 'text/css', 'href' => 'preg:/.*css\/screen\.css/')
+		);
+		$this->assertTags($result, $expected);
+
+		$result = $this->Html->css('screen', array('once' => true));
+		$this->assertEquals('', $result);
+
+		// Default is once=false
+		$result = $this->Html->css('screen');
+		$expected = array(
+			'link' => array('rel' => 'stylesheet', 'type' => 'text/css', 'href' => 'preg:/.*css\/screen\.css/')
+		);
+		$this->assertTags($result, $expected);
+	}
+
 /**
  * Test css link BC usage
  *

lib/Cake/View/Helper/HtmlHelper.php

@@ -112,11 +112,11 @@ class HtmlHelper extends AppHelper {
 	protected $_crumbs = array();
 
 /**
- * Names of script files that have been included once
+ * Names of script & css files that have been included once
  *
  * @var array
  */
-	protected $_includedScripts = array();
+	protected $_includedAssets = array();
 
 /**
  * Options for the currently opened script block buffer if any.
@@ -397,6 +397,9 @@ public function link($title, $url = null, $options = array(), $confirmMessage =
  *
  * - `inline` If set to false, the generated tag will be appended to the 'css' block,
  *   and included in the `$scripts_for_layout` layout variable. Defaults to true.
+ * - `once` Whether or not the css file should be checked for uniqueness. If true css
+ *   files  will only be included once, use false to allow the same
+ *   css to be included more than once per request.
  * - `block` Set the name of the block link/style tag will be appended to.
  *   This overrides the `inline` option.
  * - `plugin` False value will prevent parsing path as a plugin
@@ -423,7 +426,12 @@ public function css($path, $options = array()) {
 			unset($rel);
 		}
 
-		$options += array('block' => null, 'inline' => true, 'rel' => 'stylesheet');
+		$options += array(
+			'block' => null,
+			'inline' => true,
+			'once' => false,
+			'rel' => 'stylesheet'
+		);
 		if (!$options['inline'] && empty($options['block'])) {
 			$options['block'] = __FUNCTION__;
 		}
@@ -440,6 +448,12 @@ public function css($path, $options = array()) {
 			return;
 		}
 
+		if ($options['once'] && isset($this->_includedAssets[$path])) {
+			return '';
+		}
+		unset($options['once']);
+		$this->_includedAssets[$path] = true;
+
 		if (strpos($path, '//') !== false) {
 			$url = $path;
 		} else {
@@ -538,10 +552,10 @@ public function script($url, $options = array()) {
 			}
 			return null;
 		}
-		if ($options['once'] && isset($this->_includedScripts[$url])) {
+		if ($options['once'] && isset($this->_includedAssets[$url])) {
 			return null;
 		}
-		$this->_includedScripts[$url] = true;
+		$this->_includedAssets[$url] = true;
 
 		if (strpos($url, '//') === false) {
 			$url = $this->assetUrl($url, $options + array('pathPrefix' => Configure::read('App.jsBaseUrl'), 'ext' => '.js'));