<?php
/**
* CakePHP(tm) : Rapid Development Framework (https://cakephp.org)
* Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
*
* Licensed under The MIT License
* For full copyright and license information, please see the LICENSE.txt
* Redistributions of files must retain the above copyright notice.
*
* @copyright Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
* @link https://cakephp.org CakePHP(tm) Project
* @since 2.1.0
* @license https://opensource.org/licenses/mit-license.php MIT License
*/
namespace Cake\View;
use Cake\Core\Exception\Exception;
/**
* ViewBlock implements the concept of Blocks or Slots in the View layer.
* Slots or blocks are combined with extending views and layouts to afford slots
* of content that are present in a layout or parent view, but are defined by the child
* view or elements used in the view.
*/
class ViewBlock
{
/**
* Override content
*
* @var string
*/
const OVERRIDE = 'override';
/**
* Append content
*
* @var string
*/
const APPEND = 'append';
/**
* Prepend content
*
* @var string
*/
const PREPEND = 'prepend';
/**
* Block content. An array of blocks indexed by name.
*
* @var string[]
*/
protected $_blocks = [];
/**
* The active blocks being captured.
*
* @var array
*/
protected $_active = [];
/**
* Should the currently captured content be discarded on ViewBlock::end()
*
* @see \Cake\View\ViewBlock::end()
* @var bool
*/
protected $_discardActiveBufferOnEnd = false;
/**
* Start capturing output for a 'block'
*
* Blocks allow you to create slots or blocks of dynamic content in the layout.
* view files can implement some or all of a layout's slots.
*
* You can end capturing blocks using View::end(). Blocks can be output
* using View::get();
*
* @param string $name The name of the block to capture for.
* @param string $mode If ViewBlock::OVERRIDE existing content will be overridden by new content.
* If ViewBlock::APPEND content will be appended to existing content.
* If ViewBlock::PREPEND it will be prepended.
* @throws \Cake\Core\Exception\Exception When starting a block twice
* @return void
*/
public function start($name, $mode = ViewBlock::OVERRIDE)
{
if (array_key_exists($name, $this->_active)) {
throw new Exception(sprintf("A view block with the name '%s' is already/still open.", $name));
}
$this->_active[$name] = $mode;
ob_start();
}
/**
* End a capturing block. The compliment to ViewBlock::start()
*
* @return void
* @see \Cake\View\ViewBlock::start()
*/
public function end()
{
if ($this->_discardActiveBufferOnEnd) {
$this->_discardActiveBufferOnEnd = false;
ob_end_clean();
return;
}
if ($this->_active) {
$mode = end($this->_active);
$active = key($this->_active);
$content = ob_get_clean();
if ($mode === ViewBlock::OVERRIDE) {
$this->_blocks[$active] = (string)$content;
} else {
$this->concat($active, $content, $mode);
}
array_pop($this->_active);
}
}
/**
* Concat content to an existing or new block.
* Concating to a new block will create the block.
*
* Calling concat() without a value will create a new capturing
* block that needs to be finished with View::end(). The content
* of the new capturing context will be added to the existing block context.
*
* @param string $name Name of the block
* @param mixed $value The content for the block. Value will be type cast
* to string.
* @param string $mode If ViewBlock::APPEND content will be appended to existing content.
* If ViewBlock::PREPEND it will be prepended.
* @return void
*/
public function concat($name, $value = null, $mode = ViewBlock::APPEND)
{
if ($value === null) {
$this->start($name, $mode);
return;
}
if (!isset($this->_blocks[$name])) {
$this->_blocks[$name] = '';
}
if ($mode === ViewBlock::PREPEND) {
$this->_blocks[$name] = $value . $this->_blocks[$name];
} else {
$this->_blocks[$name] .= $value;
}
}
/**
* Set the content for a block. This will overwrite any
* existing content.
*
* @param string $name Name of the block
* @param mixed $value The content for the block. Value will be type cast
* to string.
* @return void
*/
public function set($name, $value)
{
$this->_blocks[$name] = (string)$value;
}
/**
* Get the content for a block.
*
* @param string $name Name of the block
* @param string $default Default string
* @return string The block content or $default if the block does not exist.
*/
public function get($name, $default = '')
{
if (!isset($this->_blocks[$name])) {
return $default;
}
return $this->_blocks[$name];
}
/**
* Check if a block exists
*
* @param string $name Name of the block
* @return bool
*/
public function exists($name)
{
return isset($this->_blocks[$name]);
}
/**
* Get the names of all the existing blocks.
*
* @return string[] An array containing the blocks.
*/
public function keys()
{
return array_keys($this->_blocks);
}
/**
* Get the name of the currently open block.
*
* @return string|null Either null or the name of the last open block.
*/
public function active()
{
end($this->_active);
return key($this->_active);
}
/**
* Get the names of the unclosed/active blocks.
*
* @return array An array of unclosed blocks.
*/
public function unclosed()
{
return $this->_active;
}
}