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<?php
/**
* @file
* Functions to aid in presenting database results as a set of pages.
*/
/**
* Query extender for pager queries.
*
* This is the "default" pager mechanism. It creates a paged query with a fixed
* number of entries per page.
*/
class PagerDefault extends SelectQueryExtender {
/**
* The highest element we've autogenerated so far.
*
* @var int
*/
static $maxElement = 0;
/**
* The number of elements per page to allow.
*
* @var int
*/
protected $limit = 10;
/**
* The unique ID of this pager on this page.
*
* @var int
*/
protected $element = NULL;
/**
* The count query that will be used for this pager.
*
* @var SelectQueryInterface
*/
protected $customCountQuery = FALSE;
public function __construct(SelectQueryInterface $query, DatabaseConnection $connection) {
parent::__construct($query, $connection);
// Add pager tag. Do this here to ensure that it is always added before
// preExecute() is called.
$this->addTag('pager');
}
/**
* Override the execute method.
*
* Before we run the query, we need to add pager-based range() instructions
* to it.
*/
public function execute() {
// Add convenience tag to mark that this is an extended query. We have to
// do this in the constructor to ensure that it is set before preExecute()
// gets called.
if (!$this->preExecute($this)) {
return NULL;
}
// A NULL limit is the "kill switch" for pager queries.
if (empty($this->limit)) {
return;
}
$this->ensureElement();
$total_items = $this->getCountQuery()->execute()->fetchField();
$current_page = pager_default_initialize($total_items, $this->limit, $this->element);
$this->range($current_page * $this->limit, $this->limit);
// Now that we've added our pager-based range instructions, run the query normally.
return $this->query->execute();
}
/**
* Ensure that there is an element associated with this query.
* If an element was not specified previously, then the value of the
* $maxElement counter is taken, after which the counter is incremented.
*
* After running this method, access $this->element to get the element for this
* query.
*/
protected function ensureElement() {
if (!isset($this->element)) {
$this->element = self::$maxElement++;
}
}
/**
* Specify the count query object to use for this pager.
*
* You will rarely need to specify a count query directly. If not specified,
* one is generated off of the pager query itself.
*
* @param SelectQueryInterface $query
* The count query object. It must return a single row with a single column,
* which is the total number of records.
*/
public function setCountQuery(SelectQueryInterface $query) {
$this->customCountQuery = $query;
}
/**
* Retrieve the count query for this pager.
*
* The count query may be specified manually or, by default, taken from the
* query we are extending.
*
* @return SelectQueryInterface
* A count query object.
*/
public function getCountQuery() {
if ($this->customCountQuery) {
return $this->customCountQuery;
}
else {
return $this->query->countQuery();
}
}
/**
* Specify the maximum number of elements per page for this query.
*
* The default if not specified is 10 items per page.
*
* @param $limit
* An integer specifying the number of elements per page. If passed a false
* value (FALSE, 0, NULL), the pager is disabled.
*/
public function limit($limit = 10) {
$this->limit = $limit;
return $this;
}
/**
* Specify the element ID for this pager query.
*
* The element is used to differentiate different pager queries on the same
* page so that they may be operated independently. If you do not specify an
* element, every pager query on the page will get a unique element. If for
* whatever reason you want to explicitly define an element for a given query,
* you may do so here.
*
* Setting the element here also increments the static $maxElement counter,
* which is used for determining the $element when there's none specified.
*
* Note that no collision detection is done when setting an element ID
* explicitly, so it is possible for two pagers to end up using the same ID
* if both are set explicitly.
*
* @param $element
*/
public function element($element) {
$this->element = $element;
if ($element >= self::$maxElement) {
self::$maxElement = $element + 1;
}
return $this;
}
}
/**
* Returns the current page being requested for display within a pager.
*
* @param $element
* An optional integer to distinguish between multiple pagers on one page.
*
* @return
* The number of the current requested page, within the pager represented by
* $element. This is determined from the URL query parameter $_GET['page'], or
* 0 by default. Note that this number may differ from the actual page being
* displayed. For example, if a search for "example text" brings up three
* pages of results, but a users visits search/node/example+text?page=10, this
* function will return 10, even though the default pager implementation
* adjusts for this and still displays the third page of search results at
* that URL.
*
* @see pager_default_initialize()
*/
function pager_find_page($element = 0) {
$page = isset($_GET['page']) ? $_GET['page'] : '';
$page_array = explode(',', $page);
if (!isset($page_array[$element])) {
$page_array[$element] = 0;
}
return (int) $page_array[$element];
}
/**
* Initializes a pager for theme('pager').
*
* This function sets up the necessary global variables so that future calls
* to theme('pager') will render a pager that correctly corresponds to the
* items being displayed.
*
* If the items being displayed result from a database query performed using
* Drupal's database API, and if you have control over the construction of the
* database query, you do not need to call this function directly; instead, you
* can simply extend the query object with the 'PagerDefault' extender before
* executing it. For example:
* @code
* $query = db_select('some_table')->extend('PagerDefault');
* @endcode
*
* However, if you are using a different method for generating the items to be
* paged through, then you should call this function in preparation.
*
* The following example shows how this function can be used in a page callback
* that invokes an external datastore with an SQL-like syntax:
* @code
* // First find the total number of items and initialize the pager.
* $where = "status = 1";
* $total = mymodule_select("SELECT COUNT(*) FROM data " . $where)->result();
* $num_per_page = variable_get('mymodule_num_per_page', 10);
* $page = pager_default_initialize($total, $num_per_page);
*
* // Next, retrieve and display the items for the current page.
* $offset = $num_per_page * $page;
* $result = mymodule_select("SELECT * FROM data " . $where . " LIMIT %d, %d", $offset, $num_per_page)->fetchAll();
* $output = theme('mymodule_results', array('result' => $result));
*
* // Finally, display the pager controls, and return.
* $output .= theme('pager');
* return $output;
* @endcode
*
* A second example involves a page callback that invokes an external search
* service where the total number of matching results is provided as part of
* the returned set (so that we do not need a separate query in order to obtain
* this information). Here, we call pager_find_page() to calculate the desired
* offset before the search is invoked:
* @code
* // Perform the query, using the requested offset from pager_find_page().
* // This comes from a URL parameter, so here we are assuming that the URL
* // parameter corresponds to an actual page of results that will exist
* // within the set.
* $page = pager_find_page();
* $num_per_page = variable_get('mymodule_num_per_page', 10);
* $offset = $num_per_page * $page;
* $result = mymodule_remote_search($keywords, $offset, $num_per_page);
*
* // Now that we have the total number of results, initialize the pager.
* pager_default_initialize($result->total, $num_per_page);
*
* // Display the search results.
* $output = theme('search_results', array('results' => $result->data, 'type' => 'remote'));
*
* // Finally, display the pager controls, and return.
* $output .= theme('pager');
* return $output;
* @endcode
*
* @param $total
* The total number of items to be paged.
* @param $limit
* The number of items the calling code will display per page.
* @param $element
* An optional integer to distinguish between multiple pagers on one page.
*
* @return
* The number of the current page, within the pager represented by $element.
* This is determined from the URL query parameter $_GET['page'], or 0 by
* default. However, if a page that does not correspond to the actual range
* of the result set was requested, this function will return the closest
* page actually within the result set.
*/
function pager_default_initialize($total, $limit, $element = 0) {
global $pager_page_array, $pager_total, $pager_total_items, $pager_limits;
$page = pager_find_page($element);
// We calculate the total of pages as ceil(items / limit).
$pager_total_items[$element] = $total;
$pager_total[$element] = ceil($pager_total_items[$element] / $limit);
$pager_page_array[$element] = max(0, min($page, ((int) $pager_total[$element]) - 1));
$pager_limits[$element] = $limit;
return $pager_page_array[$element];
}
/**
* Compose a URL query parameter array for pager links.
*
* @return
* A URL query parameter array that consists of all components of the current
* page request except for those pertaining to paging.
*/
function pager_get_query_parameters() {
$query = &drupal_static(__FUNCTION__);
if (!isset($query)) {
$query = drupal_get_query_parameters($_GET, array('q', 'page'));
}
return $query;
}
/**
* Returns HTML for a query pager.
*
* Menu callbacks that display paged query results should call theme('pager') to
* retrieve a pager control so that users can view other results. Format a list
* of nearby pages with additional query results.
*
* @param $variables
* An associative array containing:
* - tags: An array of labels for the controls in the pager.
* - element: An optional integer to distinguish between multiple pagers on
* one page.
* - parameters: An associative array of query string parameters to append to
* the pager links.
* - quantity: The number of pages in the list.
*
* @ingroup themeable
*/
function theme_pager($variables) {
$tags = $variables['tags'];
$element = $variables['element'];
$parameters = $variables['parameters'];
$quantity = $variables['quantity'];
global $pager_page_array, $pager_total;
// Calculate various markers within this pager piece:
// Middle is used to "center" pages around the current page.
$pager_middle = ceil($quantity / 2);
// current is the page we are currently paged to
$pager_current = $pager_page_array[$element] + 1;
// first is the first page listed by this pager piece (re quantity)
$pager_first = $pager_current - $pager_middle + 1;
// last is the last page listed by this pager piece (re quantity)
$pager_last = $pager_current + $quantity - $pager_middle;
// max is the maximum page number
$pager_max = $pager_total[$element];
// End of marker calculations.
// Prepare for generation loop.
$i = $pager_first;
if ($pager_last > $pager_max) {
// Adjust "center" if at end of query.
$i = $i + ($pager_max - $pager_last);
$pager_last = $pager_max;
}
if ($i <= 0) {
// Adjust "center" if at start of query.
$pager_last = $pager_last + (1 - $i);
$i = 1;
}
// End of generation loop preparation.
$li_first = theme('pager_first', array('text' => (isset($tags[0]) ? $tags[0] : t('« first')), 'element' => $element, 'parameters' => $parameters));
$li_previous = theme('pager_previous', array('text' => (isset($tags[1]) ? $tags[1] : t('‹ previous')), 'element' => $element, 'interval' => 1, 'parameters' => $parameters));
$li_next = theme('pager_next', array('text' => (isset($tags[3]) ? $tags[3] : t('next ›')), 'element' => $element, 'interval' => 1, 'parameters' => $parameters));
$li_last = theme('pager_last', array('text' => (isset($tags[4]) ? $tags[4] : t('last »')), 'element' => $element, 'parameters' => $parameters));
if ($pager_total[$element] > 1) {
if ($li_first) {
$items[] = array(
'class' => array('pager-first'),
'data' => $li_first,
);
}
if ($li_previous) {
$items[] = array(
'class' => array('pager-previous'),
'data' => $li_previous,
);
}
// When there is more than one page, create the pager list.
if ($i != $pager_max) {
if ($i > 1) {
$items[] = array(
'class' => array('pager-ellipsis'),
'data' => '…',
);
}
// Now generate the actual pager piece.
for (; $i <= $pager_last && $i <= $pager_max; $i++) {
if ($i < $pager_current) {
$items[] = array(
'class' => array('pager-item'),
'data' => theme('pager_previous', array('text' => $i, 'element' => $element, 'interval' => ($pager_current - $i), 'parameters' => $parameters)),
);
}
if ($i == $pager_current) {
$items[] = array(
'class' => array('pager-current'),
'data' => $i,
);
}
if ($i > $pager_current) {
$items[] = array(
'class' => array('pager-item'),
'data' => theme('pager_next', array('text' => $i, 'element' => $element, 'interval' => ($i - $pager_current), 'parameters' => $parameters)),
);
}
}
if ($i < $pager_max) {
$items[] = array(
'class' => array('pager-ellipsis'),
'data' => '…',
);
}
}
// End generation.
if ($li_next) {
$items[] = array(
'class' => array('pager-next'),
'data' => $li_next,
);
}
if ($li_last) {
$items[] = array(
'class' => array('pager-last'),
'data' => $li_last,
);
}
return '<h2 class="element-invisible">' . t('Pages') . '</h2>' . theme('item_list', array(
'items' => $items,
'attributes' => array('class' => array('pager')),
));
}
}
/**
* @defgroup pagerpieces Pager pieces
* @{
* Theme functions for customizing pager elements.
*
* Note that you should NOT modify this file to customize your pager.
*/
/**
* Returns HTML for the "first page" link in a query pager.
*
* @param $variables
* An associative array containing:
* - text: The name (or image) of the link.
* - element: An optional integer to distinguish between multiple pagers on
* one page.
* - parameters: An associative array of query string parameters to append to
* the pager links.
*
* @ingroup themeable
*/
function theme_pager_first($variables) {
$text = $variables['text'];
$element = $variables['element'];
$parameters = $variables['parameters'];
global $pager_page_array;
$output = '';
// If we are anywhere but the first page
if ($pager_page_array[$element] > 0) {
$output = theme('pager_link', array('text' => $text, 'page_new' => pager_load_array(0, $element, $pager_page_array), 'element' => $element, 'parameters' => $parameters));
}
return $output;
}
/**
* Returns HTML for the "previous page" link in a query pager.
*
* @param $variables
* An associative array containing:
* - text: The name (or image) of the link.
* - element: An optional integer to distinguish between multiple pagers on
* one page.
* - interval: The number of pages to move backward when the link is clicked.
* - parameters: An associative array of query string parameters to append to
* the pager links.
*
* @ingroup themeable
*/
function theme_pager_previous($variables) {
$text = $variables['text'];
$element = $variables['element'];
$interval = $variables['interval'];
$parameters = $variables['parameters'];
global $pager_page_array;
$output = '';
// If we are anywhere but the first page
if ($pager_page_array[$element] > 0) {
$page_new = pager_load_array($pager_page_array[$element] - $interval, $element, $pager_page_array);
// If the previous page is the first page, mark the link as such.
if ($page_new[$element] == 0) {
$output = theme('pager_first', array('text' => $text, 'element' => $element, 'parameters' => $parameters));
}
// The previous page is not the first page.
else {
$output = theme('pager_link', array('text' => $text, 'page_new' => $page_new, 'element' => $element, 'parameters' => $parameters));
}
}
return $output;
}
/**
* Returns HTML for the "next page" link in a query pager.
*
* @param $variables
* An associative array containing:
* - text: The name (or image) of the link.
* - element: An optional integer to distinguish between multiple pagers on
* one page.
* - interval: The number of pages to move forward when the link is clicked.
* - parameters: An associative array of query string parameters to append to
* the pager links.
*
* @ingroup themeable
*/
function theme_pager_next($variables) {
$text = $variables['text'];
$element = $variables['element'];
$interval = $variables['interval'];
$parameters = $variables['parameters'];
global $pager_page_array, $pager_total;
$output = '';
// If we are anywhere but the last page
if ($pager_page_array[$element] < ($pager_total[$element] - 1)) {
$page_new = pager_load_array($pager_page_array[$element] + $interval, $element, $pager_page_array);
// If the next page is the last page, mark the link as such.
if ($page_new[$element] == ($pager_total[$element] - 1)) {
$output = theme('pager_last', array('text' => $text, 'element' => $element, 'parameters' => $parameters));
}
// The next page is not the last page.
else {
$output = theme('pager_link', array('text' => $text, 'page_new' => $page_new, 'element' => $element, 'parameters' => $parameters));
}
}
return $output;
}
/**
* Returns HTML for the "last page" link in query pager.
*
* @param $variables
* An associative array containing:
* - text: The name (or image) of the link.
* - element: An optional integer to distinguish between multiple pagers on
* one page.
* - parameters: An associative array of query string parameters to append to
* the pager links.
*
* @ingroup themeable
*/
function theme_pager_last($variables) {
$text = $variables['text'];
$element = $variables['element'];
$parameters = $variables['parameters'];
global $pager_page_array, $pager_total;
$output = '';
// If we are anywhere but the last page
if ($pager_page_array[$element] < ($pager_total[$element] - 1)) {
$output = theme('pager_link', array('text' => $text, 'page_new' => pager_load_array($pager_total[$element] - 1, $element, $pager_page_array), 'element' => $element, 'parameters' => $parameters));
}
return $output;
}
/**
* Returns HTML for a link to a specific query result page.
*
* @param $variables
* An associative array containing:
* - text: The link text. Also used to figure out the title attribute of the
* link, if it is not provided in $variables['attributes']['title']; in
* this case, $variables['text'] must be one of the standard pager link
* text strings that would be generated by the pager theme functions, such
* as a number or t('« first').
* - page_new: The first result to display on the linked page.
* - element: An optional integer to distinguish between multiple pagers on
* one page.
* - parameters: An associative array of query string parameters to append to
* the pager link.
* - attributes: An associative array of HTML attributes to apply to the
* pager link.
*
* @see theme_pager()
*
* @ingroup themeable
*/
function theme_pager_link($variables) {
$text = $variables['text'];
$page_new = $variables['page_new'];
$element = $variables['element'];
$parameters = $variables['parameters'];
$attributes = $variables['attributes'];
$page = isset($_GET['page']) ? $_GET['page'] : '';
if ($new_page = implode(',', pager_load_array($page_new[$element], $element, explode(',', $page)))) {
$parameters['page'] = $new_page;
}
$query = array();
if (count($parameters)) {
$query = drupal_get_query_parameters($parameters, array());
}
if ($query_pager = pager_get_query_parameters()) {
$query = array_merge($query, $query_pager);
}
// Set each pager link title
if (!isset($attributes['title'])) {
static $titles = NULL;
if (!isset($titles)) {
$titles = array(
t('« first') => t('Go to first page'),
t('‹ previous') => t('Go to previous page'),
t('next ›') => t('Go to next page'),
t('last »') => t('Go to last page'),
);
}
if (isset($titles[$text])) {
$attributes['title'] = $titles[$text];
}
elseif (is_numeric($text)) {
$attributes['title'] = t('Go to page @number', array('@number' => $text));
}
}
// @todo l() cannot be used here, since it adds an 'active' class based on the
// path only (which is always the current path for pager links). Apparently,
// none of the pager links is active at any time - but it should still be
// possible to use l() here.
// @see http://drupal.org/node/1410574
$attributes['href'] = url($_GET['q'], array('query' => $query));
return '<a' . drupal_attributes($attributes) . '>' . check_plain($text) . '</a>';
}
/**
* @} End of "Pager pieces".
*/
/**
* Helper function
*
* Copies $old_array to $new_array and sets $new_array[$element] = $value
* Fills in $new_array[0 .. $element - 1] = 0
*/
function pager_load_array($value, $element, $old_array) {
$new_array = $old_array;
// Look for empty elements.
for ($i = 0; $i < $element; $i++) {
if (empty($new_array[$i])) {
// Load found empty element with 0.
$new_array[$i] = 0;
}
}
// Update the changed element.
$new_array[$element] = (int) $value;
return $new_array;
}
