From 1a39a00dfd317f6adb92c25741dae6cab18902ab Mon Sep 17 00:00:00 2001
From: Boone Gorges <boonebgorges@git.wordpress.org>
Date: Sat, 21 May 2016 17:26:55 +0000
Subject: [PATCH] Cache queries in `get_page_by_path()`.

Props spacedmonkey.
Fixes #36711.

git-svn-id: https://develop.svn.wordpress.org/trunk@37479 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/post.php                   |  21 ++++
 tests/phpunit/tests/post/getPageByPath.php | 119 +++++++++++++++++++++
 2 files changed, 140 insertions(+)

diff --git a/src/wp-includes/post.php b/src/wp-includes/post.php
index 1920e84f9a..ceaa1d96a8 100644
--- a/src/wp-includes/post.php
+++ b/src/wp-includes/post.php
@@ -4231,6 +4231,24 @@ function get_page( $page, $output = OBJECT, $filter = 'raw') {
 function get_page_by_path( $page_path, $output = OBJECT, $post_type = 'page' ) {
 	global $wpdb;
 
+	$last_changed = wp_cache_get( 'last_changed', 'posts' );
+	if ( false === $last_changed ) {
+		$last_changed = microtime();
+		wp_cache_set( 'last_changed', $last_changed, 'posts' );
+	}
+
+	$hash = md5( $page_path . serialize( $post_type ) );
+	$cache_key = "get_page_by_path:$hash:$last_changed";
+	$cached = wp_cache_get( $cache_key, 'posts' );
+	if ( false !== $cached ) {
+		// Special case: '0' is a bad `$page_path`.
+		if ( '0' === $cached || 0 === $cached ) {
+			return;
+		} else {
+			return get_post( $cached );
+		}
+	}
+
 	$page_path = rawurlencode(urldecode($page_path));
 	$page_path = str_replace('%2F', '/', $page_path);
 	$page_path = str_replace('%20', ' ', $page_path);
@@ -4285,6 +4303,9 @@ function get_page_by_path( $page_path, $output = OBJECT, $post_type = 'page' ) {
 		}
 	}
 
+	// We cache misses as well as hits.
+	wp_cache_set( $cache_key, $foundid, 'posts' );
+
 	if ( $foundid ) {
 		return get_post( $foundid, $output );
 	}
diff --git a/tests/phpunit/tests/post/getPageByPath.php b/tests/phpunit/tests/post/getPageByPath.php
index 7bd3610ce2..01271bcaa2 100644
--- a/tests/phpunit/tests/post/getPageByPath.php
+++ b/tests/phpunit/tests/post/getPageByPath.php
@@ -123,4 +123,123 @@ class Tests_Post_GetPageByPath extends WP_UnitTestCase {
 
 		$this->assertNull( $found );
 	}
+
+	/**
+	 * @ticket 36711
+	 */
+	public function test_should_hit_cache() {
+		global $wpdb;
+
+		$page = self::factory()->post->create( array(
+			'post_type' => 'page',
+			'post_name' => 'foo',
+		) );
+
+		// Prime cache.
+		$found = get_page_by_path( 'foo' );
+		$this->assertSame( $page, $found->ID );
+
+		$num_queries = $wpdb->num_queries;
+
+		$found = get_page_by_path( 'foo' );
+		$this->assertSame( $page, $found->ID );
+		$this->assertSame( $num_queries, $wpdb->num_queries );
+	}
+
+	/**
+	 * @ticket 36711
+	 */
+	public function test_bad_path_should_be_cached() {
+		global $wpdb;
+
+		// Prime cache.
+		$found = get_page_by_path( 'foo' );
+		$this->assertNull( $found );
+
+		$num_queries = $wpdb->num_queries;
+
+		$found = get_page_by_path( 'foo' );
+		$this->assertNull( $found );
+		$this->assertSame( $num_queries, $wpdb->num_queries );
+	}
+
+	/**
+	 * @ticket 36711
+	 */
+	public function test_bad_path_served_from_cache_should_not_fall_back_on_current_post() {
+		global $wpdb, $post;
+
+		// Fake the global.
+		$post = self::factory()->post->create_and_get();
+
+		// Prime cache.
+		$found = get_page_by_path( 'foo' );
+		$this->assertNull( $found );
+
+		$num_queries = $wpdb->num_queries;
+
+		$found = get_page_by_path( 'foo' );
+		$this->assertNull( $found );
+		$this->assertSame( $num_queries, $wpdb->num_queries );
+
+		unset( $post );
+	}
+
+	/**
+	 * @ticket 36711
+	 */
+	public function test_cache_should_not_match_post_in_different_post_type_with_same_path() {
+		global $wpdb;
+
+		register_post_type( 'wptests_pt' );
+
+		$p1 = self::factory()->post->create( array(
+			'post_type' => 'page',
+			'post_name' => 'foo',
+		) );
+
+		$p2 = self::factory()->post->create( array(
+			'post_type' => 'wptests_pt',
+			'post_name' => 'foo',
+		) );
+
+		// Prime cache for the page.
+		$found = get_page_by_path( 'foo' );
+		$this->assertSame( $p1, $found->ID );
+
+		$num_queries = $wpdb->num_queries;
+
+		$found = get_page_by_path( 'foo', OBJECT, 'wptests_pt' );
+		$this->assertSame( $p2, $found->ID );
+		$num_queries++;
+		$this->assertSame( $num_queries, $wpdb->num_queries );
+	}
+
+	/**
+	 * @ticket 36711
+	 */
+	public function test_cache_should_be_invalidated_when_post_name_is_edited() {
+		global $wpdb;
+
+		$page = self::factory()->post->create( array(
+			'post_type' => 'page',
+			'post_name' => 'foo',
+		) );
+
+		// Prime cache.
+		$found = get_page_by_path( 'foo' );
+		$this->assertSame( $page, $found->ID );
+
+		wp_update_post( array(
+			'ID' => $page,
+			'post_name' => 'bar',
+		) );
+
+		$num_queries = $wpdb->num_queries;
+
+		$found = get_page_by_path( 'bar' );
+		$this->assertSame( $page, $found->ID );
+		$num_queries++;
+		$this->assertSame( $num_queries, $wpdb->num_queries );
+	}
 }