From 4973a0cb41245684be50036ecf1db65adacb7663 Mon Sep 17 00:00:00 2001
From: Sam Hemelryk <sam@moodle.com>
Date: Mon, 19 Aug 2013 10:00:44 +1200
Subject: [PATCH] MDL-41106 cache: tidied up several elements

---
 cache/classes/loaders.php    | 95 +++++++++++++++++++++++++++---------
 cache/stores/session/lib.php | 30 ++++++++----
 cache/tests/cache_test.php   | 91 +++++++++++++++++++++++++++++++++-
 cache/tests/fixtures/lib.php | 18 +++++++
 4 files changed, 201 insertions(+), 33 deletions(-)

diff --git a/cache/classes/loaders.php b/cache/classes/loaders.php
index 69949c0b859..6de94e299b3 100644
--- a/cache/classes/loaders.php
+++ b/cache/classes/loaders.php
@@ -271,7 +271,7 @@ class cache implements cache_loader {
      *      In advanced cases an array may be useful such as in situations requiring the multi-key functionality.
      * @param int $strictness One of IGNORE_MISSING | MUST_EXIST
      * @return mixed|false The data from the cache or false if the key did not exist within the cache.
-     * @throws moodle_exception
+     * @throws coding_exception
      */
     public function get($key, $strictness = IGNORE_MISSING) {
         // 1. Parse the key.
@@ -329,7 +329,7 @@ class cache implements cache_loader {
         }
         // 5. Validate strictness.
         if ($strictness === MUST_EXIST && $result === false) {
-            throw new moodle_exception('Requested key did not exist in any cache stores and could not be loaded.');
+            throw new coding_exception('Requested key did not exist in any cache stores and could not be loaded.');
         }
         // 6. Set it to the store if we got it from the loader/datasource.
         if ($setaftervalidation) {
@@ -363,7 +363,7 @@ class cache implements cache_loader {
      * @return array An array of key value pairs for the items that could be retrieved from the cache.
      *      If MUST_EXIST was used and not all keys existed within the cache then an exception will be thrown.
      *      Otherwise any key that did not exist will have a data value of false within the results.
-     * @throws moodle_exception
+     * @throws coding_exception
      */
     public function get_many(array $keys, $strictness = IGNORE_MISSING) {
 
@@ -420,7 +420,7 @@ class cache implements cache_loader {
             $missingkeys = array();
             foreach ($result as $key => $value) {
                 if ($value === false) {
-                    $missingkeys[] = ($usingloader) ? $key : $parsedkeys[$key];
+                    $missingkeys[] = $parsedkeys[$key];
                 }
             }
             if (!empty($missingkeys)) {
@@ -430,11 +430,9 @@ class cache implements cache_loader {
                     $resultmissing = $this->datasource->load_many_for_cache($missingkeys);
                 }
                 foreach ($resultmissing as $key => $value) {
-                    $pkey = ($usingloader) ? $key : $keysparsed[$key];
-                    $realkey = ($usingloader) ? $parsedkeys[$key] : $key;
-                    $result[$pkey] = $value;
+                    $result[$keysparsed[$key]] = $value;
                     if ($value !== false) {
-                        $this->set($realkey, $value);
+                        $this->set($key, $value);
                     }
                 }
                 unset($resultmissing);
@@ -453,7 +451,7 @@ class cache implements cache_loader {
         if ($strictness === MUST_EXIST) {
             foreach ($keys as $key) {
                 if (!array_key_exists($key, $fullresult)) {
-                    throw new moodle_exception('Not all the requested keys existed within the cache stores.');
+                    throw new coding_exception('Not all the requested keys existed within the cache stores.');
                 }
             }
         }
@@ -483,6 +481,11 @@ class cache implements cache_loader {
         if ($this->perfdebug) {
             cache_helper::record_cache_set($this->storetype, $this->definition->get_id());
         }
+        if ($this->loader !== false) {
+            // We have a loader available set it there as well.
+            // We have to let the loader do its own parsing of data as it may be unique.
+            $this->loader->set($key, $data);
+        }
         if (is_object($data) && $data instanceof cacheable_object) {
             $data = new cache_cached_object($data);
         } else if (!is_scalar($data)) {
@@ -506,6 +509,7 @@ class cache implements cache_loader {
      * Removes references where required.
      *
      * @param stdClass|array $data
+     * @return mixed What ever was put in but without any references.
      */
     protected function unref($data) {
         if ($this->definition->uses_simple_data()) {
@@ -593,6 +597,11 @@ class cache implements cache_loader {
      *      ... if they care that is.
      */
     public function set_many(array $keyvaluearray) {
+        if ($this->loader !== false) {
+            // We have a loader available set it there as well.
+            // We have to let the loader do its own parsing of data as it may be unique.
+            $this->loader->set_many($keyvaluearray);
+        }
         $data = array();
         $simulatettl = $this->has_a_ttl() && !$this->store_supports_native_ttl();
         $usepersistcache = $this->is_using_persist_cache();
@@ -1340,7 +1349,6 @@ class cache_application extends cache implements cache_loader_with_locking {
      * @param string|int $key The key for the data being requested.
      * @param int $strictness One of IGNORE_MISSING | MUST_EXIST
      * @return mixed|false The data from the cache or false if the key did not exist within the cache.
-     * @throws moodle_exception
      */
     public function get($key, $strictness = IGNORE_MISSING) {
         if ($this->requirelockingread && $this->check_lock_state($key) === false) {
@@ -1364,7 +1372,7 @@ class cache_application extends cache implements cache_loader_with_locking {
      * @return array An array of key value pairs for the items that could be retrieved from the cache.
      *      If MUST_EXIST was used and not all keys existed within the cache then an exception will be thrown.
      *      Otherwise any key that did not exist will have a data value of false within the results.
-     * @throws moodle_exception
+     * @throws coding_exception
      */
     public function get_many(array $keys, $strictness = IGNORE_MISSING) {
         if ($this->requirelockingread) {
@@ -1498,7 +1506,7 @@ class cache_session extends cache {
     /**
      * This is the key used to track last access.
      */
-    const LASTACCESS = 'lastaccess';
+    const LASTACCESS = '__lastaccess__';
 
     /**
      * Override the cache::construct method.
@@ -1599,7 +1607,7 @@ class cache_session extends cache {
     protected function parse_key($key) {
         $prefix = $this->get_key_prefix();
         if ($key === self::LASTACCESS) {
-            return '__lastaccess__'.$prefix;
+            return $key.$prefix;
         }
         return $prefix.'_'.parent::parse_key($key);
     }
@@ -1651,7 +1659,7 @@ class cache_session extends cache {
      *      In advanced cases an array may be useful such as in situations requiring the multi-key functionality.
      * @param int $strictness One of IGNORE_MISSING | MUST_EXIST
      * @return mixed|false The data from the cache or false if the key did not exist within the cache.
-     * @throws moodle_exception
+     * @throws coding_exception
      */
     public function get($key, $strictness = IGNORE_MISSING) {
         // Check the tracked user.
@@ -1695,7 +1703,7 @@ class cache_session extends cache {
         }
         // 5. Validate strictness.
         if ($strictness === MUST_EXIST && $result === false) {
-            throw new moodle_exception('Requested key did not exist in any cache stores and could not be loaded.');
+            throw new coding_exception('Requested key did not exist in any cache stores and could not be loaded.');
         }
         // 6. Make sure we don't pass back anything that could be a reference.
         //    We don't want people modifying the data in the cache.
@@ -1728,6 +1736,12 @@ class cache_session extends cache {
      */
     public function set($key, $data) {
         $this->check_tracked_user();
+        $loader = $this->get_loader();
+        if ($loader !== false) {
+            // We have a loader available set it there as well.
+            // We have to let the loader do its own parsing of data as it may be unique.
+            $loader->set($key, $data);
+        }
         if ($this->perfdebug) {
             cache_helper::record_cache_set($this->storetype, $this->get_definition()->get_id());
         }
@@ -1780,7 +1794,7 @@ class cache_session extends cache {
      * @return array An array of key value pairs for the items that could be retrieved from the cache.
      *      If MUST_EXIST was used and not all keys existed within the cache then an exception will be thrown.
      *      Otherwise any key that did not exist will have a data value of false within the results.
-     * @throws moodle_exception
+     * @throws coding_exception
      */
     public function get_many(array $keys, $strictness = IGNORE_MISSING) {
         $this->check_tracked_user();
@@ -1788,17 +1802,19 @@ class cache_session extends cache {
         $keymap = array();
         foreach ($keys as $key) {
             $parsedkey = $this->parse_key($key);
-            $parsedkeys[] = $parsedkey;
+            $parsedkeys[$key] = $parsedkey;
             $keymap[$parsedkey] = $key;
         }
         $result = $this->get_store()->get_many($parsedkeys);
-        $mustexist = $strictness === MUST_EXIST;
         $return = array();
+        $missingkeys = array();
+        $hasmissingkeys = false;
         foreach ($result as $parsedkey => $value) {
+            $key = $keymap[$parsedkey];
             if ($value instanceof cache_ttl_wrapper) {
                 /* @var cache_ttl_wrapper $value */
                 if ($value->has_expired()) {
-                    $this->get_store()->delete($parsedkey);
+                    $this->delete($keymap[$parsedkey]);
                     $value = false;
                 } else {
                     $value = $value->data;
@@ -1808,11 +1824,40 @@ class cache_session extends cache {
                 /* @var cache_cached_object $value */
                 $value = $value->restore_object();
             }
-            if ($value === false && $mustexist) {
-                throw new moodle_exception('Not all the requested keys existed within the cache stores.');
+            $return[$key] = $value;
+            if ($value === false) {
+                $hasmissingkeys = true;
+                $missingkeys[$parsedkey] = $key;
             }
-            $return[$keymap[$parsedkey]] = $value;
         }
+        if ($hasmissingkeys) {
+            // We've got missing keys - we've got to check any loaders or data sources.
+            $loader = $this->get_loader();
+            $datasource = $this->get_datasource();
+            if ($loader !== false) {
+                foreach ($loader->get_many($missingkeys) as $key => $value) {
+                    if ($value !== false) {
+                        $return[$key] = $value;
+                        unset($missingkeys[$parsedkeys[$key]]);
+                    }
+                }
+            }
+            $hasmissingkeys = count($missingkeys) > 0;
+            if ($datasource !== false && $hasmissingkeys) {
+                // We're still missing keys but we've got a datasource.
+                foreach ($datasource->load_many_for_cache($missingkeys) as $key => $value) {
+                    if ($value !== false) {
+                        $return[$key] = $value;
+                        unset($missingkeys[$parsedkeys[$key]]);
+                    }
+                }
+                $hasmissingkeys = count($missingkeys) > 0;
+            }
+        }
+        if ($hasmissingkeys && $strictness === MUST_EXIST) {
+            throw new coding_exception('Requested key did not exist in any cache stores and could not be loaded.');
+        }
+
         return $return;
 
     }
@@ -1859,6 +1904,12 @@ class cache_session extends cache {
      */
     public function set_many(array $keyvaluearray) {
         $this->check_tracked_user();
+        $loader = $this->get_loader();
+        if ($loader !== false) {
+            // We have a loader available set it there as well.
+            // We have to let the loader do its own parsing of data as it may be unique.
+            $loader->set_many($keyvaluearray);
+        }
         $data = array();
         $definitionid = $this->get_definition()->get_ttl();
         $simulatettl = $this->has_a_ttl() && !$this->store_supports_native_ttl();
diff --git a/cache/stores/session/lib.php b/cache/stores/session/lib.php
index 3187dfa7c32..d1f735d3b59 100644
--- a/cache/stores/session/lib.php
+++ b/cache/stores/session/lib.php
@@ -190,7 +190,7 @@ class cachestore_session extends session_data_store implements cache_is_key_awar
      */
     public function initialise(cache_definition $definition) {
         $this->storeid = $definition->generate_definition_hash();
-        $this->store = &self::register_store_id($definition->get_id());
+        $this->store = &self::register_store_id($this->name.'-'.$definition->get_id());
         $this->ttl = $definition->get_ttl();
         $this->check_ttl();
     }
@@ -374,6 +374,9 @@ class cachestore_session extends session_data_store implements cache_is_key_awar
      * @return bool Returns true if the operation was a success, false otherwise.
      */
     public function delete($key) {
+        if (!isset($this->store[$key])) {
+            return false;
+        }
         unset($this->store[$key]);
         return true;
     }
@@ -385,6 +388,7 @@ class cachestore_session extends session_data_store implements cache_is_key_awar
      * @return int The number of items successfully deleted.
      */
     public function delete_many(array $keys) {
+        // The number of items that have been successfully deleted.
         $count = 0;
         foreach ($keys as $key) {
             unset($this->store[$key]);
@@ -445,23 +449,23 @@ class cachestore_session extends session_data_store implements cache_is_key_awar
      * @return int number of removed elements
      */
     protected function check_ttl() {
-        if ($this->ttl == 0) {
+        if ($this->ttl === 0) {
             return 0;
         }
         $maxtime = cache::now() - $this->ttl;
-        $c = 0;
+        $count = 0;
         for ($value = reset($this->store); $value !== false; $value = next($this->store)) {
             if ($value[1] >= $maxtime) {
-                // We know that elements are sorted by ttl so no need to continue;
+                // We know that elements are sorted by ttl so no need to continue.
                 break;
             }
-            $c++;
+            $count++;
         }
-        if ($c) {
-            // Remove first $c elements as they are expired.
-            $this->store = array_slice($this->store, $c, null, true);
+        if ($count) {
+            // Remove first $count elements as they are expired.
+            $this->store = array_slice($this->store, $count, null, true);
         }
-        return $c;
+        return $count;
     }
 
     /**
@@ -489,4 +493,12 @@ class cachestore_session extends session_data_store implements cache_is_key_awar
         }
         return $return;
     }
+
+    /**
+     * This store supports native TTL handling.
+     * @return bool
+     */
+    public function store_supports_native_ttl() {
+        return true;
+    }
 }
diff --git a/cache/tests/cache_test.php b/cache/tests/cache_test.php
index 26a331d8440..9d36ef6a1f2 100644
--- a/cache/tests/cache_test.php
+++ b/cache/tests/cache_test.php
@@ -1109,9 +1109,9 @@ class cache_phpunit_tests extends advanced_testcase {
     }
 
     /**
-     * Test that multiple loaders work ok.
+     * Test that multiple application loaders work ok.
      */
-    public function test_multiple_loaders() {
+    public function test_multiple_application_loaders() {
         $instance = cache_config_phpunittest::instance(true);
         $instance->phpunit_add_file_store('phpunittest1');
         $instance->phpunit_add_file_store('phpunittest2');
@@ -1156,6 +1156,93 @@ class cache_phpunit_tests extends advanced_testcase {
         $this->assertFalse($result['a']);
         $this->assertEquals('B', $result['b']);
         $this->assertFalse($result['c']);
+
+        // Test non-recursive deletes.
+        $this->assertTrue($cache->set('test', 'test'));
+        $this->assertSame('test', $cache->get('test'));
+        $this->assertTrue($cache->delete('test', false));
+        // We should still have it on a deeper loader.
+        $this->assertSame('test', $cache->get('test'));
+        // Test non-recusive with many functions.
+        $this->assertSame(3, $cache->set_many(array(
+            'one' => 'one',
+            'two' => 'two',
+            'three' => 'three'
+        )));
+        $this->assertSame('one', $cache->get('one'));
+        $this->assertSame(array('two' => 'two', 'three' => 'three'), $cache->get_many(array('two', 'three')));
+        $this->assertSame(3, $cache->delete_many(array('one', 'two', 'three'), false));
+        $this->assertSame('one', $cache->get('one'));
+        $this->assertSame(array('two' => 'two', 'three' => 'three'), $cache->get_many(array('two', 'three')));
+    }
+
+    /**
+     * Test that multiple application loaders work ok.
+     */
+    public function test_multiple_session_loaders() {
+        /* @var cache_config_phpunittest $instance */
+        $instance = cache_config_phpunittest::instance(true);
+        $instance->phpunit_add_session_store('phpunittest1');
+        $instance->phpunit_add_session_store('phpunittest2');
+        $instance->phpunit_add_definition('phpunit/multi_loader', array(
+            'mode' => cache_store::MODE_SESSION,
+            'component' => 'phpunit',
+            'area' => 'multi_loader'
+        ));
+        $instance->phpunit_add_definition_mapping('phpunit/multi_loader', 'phpunittest1', 3);
+        $instance->phpunit_add_definition_mapping('phpunit/multi_loader', 'phpunittest2', 2);
+
+        $cache = cache::make('phpunit', 'multi_loader');
+        $this->assertInstanceOf('cache_session', $cache);
+        $this->assertFalse($cache->get('test'));
+        $this->assertTrue($cache->set('test', 'test'));
+        $this->assertEquals('test', $cache->get('test'));
+        $this->assertTrue($cache->delete('test'));
+        $this->assertFalse($cache->get('test'));
+        $this->assertTrue($cache->set('test', 'test'));
+        $this->assertTrue($cache->purge());
+        $this->assertFalse($cache->get('test'));
+
+        // Test the many commands.
+        $this->assertEquals(3, $cache->set_many(array('a' => 'A', 'b' => 'B', 'c' => 'C')));
+        $result = $cache->get_many(array('a', 'b', 'c'));
+        $this->assertInternalType('array', $result);
+        $this->assertCount(3, $result);
+        $this->assertArrayHasKey('a', $result);
+        $this->assertArrayHasKey('b', $result);
+        $this->assertArrayHasKey('c', $result);
+        $this->assertEquals('A', $result['a']);
+        $this->assertEquals('B', $result['b']);
+        $this->assertEquals('C', $result['c']);
+        $this->assertEquals($result, $cache->get_many(array('a', 'b', 'c')));
+        $this->assertEquals(2, $cache->delete_many(array('a', 'c')));
+        $result = $cache->get_many(array('a', 'b', 'c'));
+        $this->assertInternalType('array', $result);
+        $this->assertCount(3, $result);
+        $this->assertArrayHasKey('a', $result);
+        $this->assertArrayHasKey('b', $result);
+        $this->assertArrayHasKey('c', $result);
+        $this->assertFalse($result['a']);
+        $this->assertEquals('B', $result['b']);
+        $this->assertFalse($result['c']);
+
+        // Test non-recursive deletes.
+        $this->assertTrue($cache->set('test', 'test'));
+        $this->assertSame('test', $cache->get('test'));
+        $this->assertTrue($cache->delete('test', false));
+        // We should still have it on a deeper loader.
+        $this->assertSame('test', $cache->get('test'));
+        // Test non-recusive with many functions.
+        $this->assertSame(3, $cache->set_many(array(
+            'one' => 'one',
+            'two' => 'two',
+            'three' => 'three'
+        )));
+        $this->assertSame('one', $cache->get('one'));
+        $this->assertSame(array('two' => 'two', 'three' => 'three'), $cache->get_many(array('two', 'three')));
+        $this->assertSame(3, $cache->delete_many(array('one', 'two', 'three'), false));
+        $this->assertSame('one', $cache->get('one'));
+        $this->assertSame(array('two' => 'two', 'three' => 'three'), $cache->get_many(array('two', 'three')));
     }
 
     /**
diff --git a/cache/tests/fixtures/lib.php b/cache/tests/fixtures/lib.php
index b68bfd4c8fd..fda991f703a 100644
--- a/cache/tests/fixtures/lib.php
+++ b/cache/tests/fixtures/lib.php
@@ -86,6 +86,24 @@ class cache_config_phpunittest extends cache_config_writer {
         );
     }
 
+    /**
+     * Forcefully adds a session store.
+     *
+     * @param string $name
+     */
+    public function phpunit_add_session_store($name) {
+        $this->configstores[$name] = array(
+            'name' => $name,
+            'plugin' => 'session',
+            'configuration' => array(),
+            'features' => 14,
+            'modes' => 2,
+            'default' => true,
+            'class' => 'cachestore_session',
+            'lock' => 'cachelock_file_default',
+        );
+    }
+
     /**
      * Forcefully injects a definition => store mapping.
      *