cache_disabled Class Reference

Required as it is needed for cache_config_disabled which extends cache_config_writer. More...

Inheritance diagram for cache_disabled:

Public Member Functions
	__construct (cache_definition $definition, cache_store $store, $loader=null)
	Constructs the cache. More...
	delete ($key, $recurse=true)
	Deletes an item from the cache. More...
	delete_many (array $keys, $recurse=true)
	Deletes many items at once from the cache. More...
	get ($key, $strictness=IGNORE_MISSING)
	Gets a key from the cache. More...
	get_many (array $keys, $strictness=IGNORE_MISSING)
	Gets many keys at once from the cache. More...
	has ($key)
	Test is a cache has a key. More...
	has ($key, $tryloadifpossible=false)
	Checks if the cache has the requested key. More...
	has_all (array $keys)
	Checks if the cache has all of the requested keys. More...
	has_any (array $keys)
	Checks if the cache has any of the requested keys. More...
	purge ()
	Purges all items from the cache. More...
	purge_current_user ()
	Subclasses may support purging cache of all data belonging to the current user.
	set ($key, $data)
	Sets a key value pair in the cache. More...
	set_identifiers (array $identifiers)
	Alters the identifiers that have been provided to the definition. More...
	set_many (array $keyvaluearray)
	Sets many key value pairs in the cache at once. More...

Static Public Member Functions
static	compare_purge_tokens ($tokena, $tokenb)
	Compare a pair of purge tokens. More...
static	get_purge_token ($reset=false)
	Get a 'purge' token used for cache invalidation handling. More...
static	make ($component, $area, array $identifiers=array(), $unused=null)
	Creates a new cache instance for a pre-defined definition. More...
static	make_from_params ($mode, $component, $area, array $identifiers=array(), array $options=array())
	Creates a new cache instance based upon the given params. More...
static	now ($float=false)
	Returns the timestamp from the first request for the time from the cache API. More...

Protected Member Functions
	deep_clone ($value)
	Creates a reference free clone of the given value. More...
	delete_from_persist_cache ()
	get_datasource ()
	Returns the data source associated with this cache. More...
	get_definition ()
	Returns the cache definition. More...
	get_from_persist_cache ()
	get_loader ()
	Returns the loader associated with this instance. More...
	get_store ()
	Returns the cache store. More...
	handle_invalidation_events ()
	Process any outstanding invalidation events for the cache we are registering,. More...
	has_a_ttl ()
	Returns true if the cache is making use of a ttl. More...
	is_in_persist_cache ()
	is_using_persist_cache ()
	parse_key ($key)
	Parses the key turning it into a string (or array is required) suitable to be passed to the cache store. More...
	requires_serialisation ($value, $depth=1)
	Checks to see if a var requires serialisation. More...
	set_data_source (cache_data_source $datasource)
	Set the data source for this cache. More...
	set_in_persist_cache ()
	set_is_sub_loader ($setting=true)
	Used to inform the loader of its state as a sub loader, or as the top of the chain. More...
	set_loader (cache_loader $loader)
	Set the loader for this cache. More...
	static_acceleration_delete ($key)
	Deletes an item from the static acceleration array. More...
	static_acceleration_get ($key)
	Returns the item from the static acceleration array if it exists there. More...
	static_acceleration_has ($key)
	Returns true if the requested key exists within the static acceleration array. More...
	static_acceleration_purge ()
	Purge the static acceleration cache.
	static_acceleration_set ($key, $data)
	Sets a key value pair into the static acceleration array. More...
	store_supports_key_awareness ()
	Returns true if the store supports key awareness. More...
	store_supports_native_locking ()
	Returns true if the store natively supports locking. More...
	store_supports_native_ttl ()
	Returns true if the cache store supports native ttl. More...
	unref ($data)
	Removes references where required. More...
	use_static_acceleration ()
	Returns true if this cache is making use of the static acceleration array. More...

Protected Attributes
bool	$perfdebug = false
	Gets set to true if we want to collect performance information about the cache API.
strubg	$storetype = 'unknown'
	Gets set to the class name of the store during initialisation. More...
bool	$subloader = false
	Determines if this loader is a sub loader, not the top of the chain.

Static Protected Attributes
static int	$now
	We need a timestamp to use within the cache API. More...
static string	$purgetoken
	A purge token used to distinguish between multiple cache purges in the same second. More...

Detailed Description

Required as it is needed for cache_config_disabled which extends cache_config_writer.

The cache loader class used when the Cache has been disabled.

Copyright

2012 Sam Hemelryk

License

http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

Constructor & Destructor Documentation

__construct()

cache_disabled::__construct	(	cache_definition	$definition,
		cache_store	$store,
			$loader = null
	)

Constructs the cache.

Parameters

cache_definition	$definition
cache_store	$store
null	$loader	Unused.

Reimplemented from cache.

Member Function Documentation

compare_purge_tokens()

static cache::compare_purge_tokens (   $tokena,   $tokenb  )

staticinherited

Compare a pair of purge tokens.

If the two tokens are identical, then the return value is 0. If the time component of token A is newer than token B, then a positive value is returned. If the time component of token B is newer than token A, then a negative value is returned.

Note: This function is intended for use from within the Cache API only and not by plugins, or cache stores.

Parameters

string	$tokena
string	$tokenb

Return values

int

deep_clone()

cache::deep_clone (   $value )

protectedinherited

Creates a reference free clone of the given value.

Parameters

mixed

$value

Return values

mixed

delete()

cache_disabled::delete	(		$key,
			$recurse = true
	)

Deletes an item from the cache.

Parameters

int | string	$key	Unused.
bool	$recurse	Unused.

Return values

bool

Reimplemented from cache.

delete_from_persist_cache()

cache::delete_from_persist_cache ( )

protectedinherited

Deprecated:

since 2.6

See also

cache::static_acceleration_delete()

delete_many()

cache_disabled::delete_many	(	array	$keys,
			$recurse = true
	)

Deletes many items at once from the cache.

Parameters

array	$keys	Unused.
bool	$recurse	Unused.

Return values

int

Reimplemented from cache.

get()

cache_disabled::get	(		$key,
			$strictness = IGNORE_MISSING
	)

Gets a key from the cache.

Parameters

int | string	$key
int	$strictness	Unused.

Return values

bool

Reimplemented from cache.

get_datasource()

cache::get_datasource ( )

protectedinherited

Returns the data source associated with this cache.

Since

Moodle 2.4.4

Return values

cache_data_source|false

get_definition()

cache::get_definition ( )

protectedinherited

Returns the cache definition.

Return values

cache_definition

get_from_persist_cache()

cache::get_from_persist_cache ( )

protectedinherited

Deprecated:

since 2.6

See also

cache::static_acceleration_get

get_loader()

cache::get_loader ( )

protectedinherited

Returns the loader associated with this instance.

Since

Moodle 2.4.4

Return values

cache|false

get_many()

cache_disabled::get_many	(	array	$keys,
			$strictness = IGNORE_MISSING
	)

Gets many keys at once from the cache.

Parameters

array	$keys
int	$strictness	Unused.

Return values

array

Reimplemented from cache.

get_purge_token()

static cache::get_purge_token (   $reset = false )

staticinherited

Get a 'purge' token used for cache invalidation handling.

Note: This function is intended for use from within the Cache API only and not by plugins, or cache stores.

Parameters

bool

$reset

Whether to reset the token and generate a new one.

Return values

string

get_store()

cache::get_store ( )

protectedinherited

Returns the cache store.

Return values

cache_store

handle_invalidation_events()

cache::handle_invalidation_events ( )

protectedinherited

Process any outstanding invalidation events for the cache we are registering,.

Identifiers and event invalidation are not compatible with each other at this time. As a result the cache does not need to consider identifiers when working out what to invalidate.

has() [1/2]

cache_loader::has (   $key )

inherited

Test is a cache has a key.

The use of the has methods is strongly discouraged. In a high load environment the cache may well change between the test and any subsequent action (get, set, delete etc). Instead it is recommended to write your code in such a way they it performs the following steps:

1. Attempt to retrieve the information.
2. Generate the information.
3. Attempt to set the information

Its also worth mentioning that not all stores support key tests. For stores that don't support key tests this functionality is mimicked by using the equivalent get method. Just one more reason you should not use these methods unless you have a very good reason to do so.

Parameters

string | int

$key

Return values

bool	True if the cache has the requested key, false otherwise.

has() [2/2]

cache_disabled::has	(		$key,
			$tryloadifpossible = false
	)

Checks if the cache has the requested key.

Parameters

int | string	$key	Unused.
bool	$tryloadifpossible	Unused.

Return values

bool

Reimplemented from cache.

has_a_ttl()

cache::has_a_ttl ( )

protectedinherited

Returns true if the cache is making use of a ttl.

Return values

bool

has_all()

cache_disabled::has_all

(

array

$keys

)

Checks if the cache has all of the requested keys.

Parameters

array

$keys

Unused.

Return values

bool

Reimplemented from cache.

has_any()

cache_disabled::has_any

(

array

$keys

)

Checks if the cache has any of the requested keys.

Parameters

array

$keys

Unused.

Return values

bool

Reimplemented from cache.

is_in_persist_cache()

cache::is_in_persist_cache ( )

protectedinherited

See also

cache::static_acceleration_has

Deprecated:

since 2.6

is_using_persist_cache()

cache::is_using_persist_cache ( )

protectedinherited

Deprecated:

since 2.6

See also

cache::use_static_acceleration()

make()

static cache::make (   $component,   $area, array  $identifiers = array(),   $unused = null  )

staticinherited

Creates a new cache instance for a pre-defined definition.

Parameters

string	$component	The component for the definition
string	$area	The area for the definition
array	$identifiers	Any additional identifiers that should be provided to the definition.
string	$unused	Used to be datasourceaggregate but that was removed and this is now unused.

Return values

cache_application|cache_session|cache_store

make_from_params()

static cache::make_from_params (   $mode,   $component,   $area, array  $identifiers = array(), array  $options = array()  )

staticinherited

Creates a new cache instance based upon the given params.

Parameters

int	$mode	One of cache_store::MODE_*
string	$component	The component this cache relates to.
string	$area	The area this cache relates to.
array	$identifiers	Any additional identifiers that should be provided to the definition.
array	$options	An array of options, available options are: simplekeys : Set to true if the keys you will use are a-zA-Z0-9_ simpledata : Set to true if the type of the data you are going to store is scalar, or an array of scalar vars staticacceleration : If set to true the cache will hold onto data passing through it. staticaccelerationsize : The max size for the static acceleration array.

Return values

cache_application|cache_session|cache_store

now()

static cache::now (   $float = false )

staticinherited

Returns the timestamp from the first request for the time from the cache API.

This stamp needs to be used for all ttl and time based operations to ensure that we don't end up with timing issues.

Parameters

bool

$float

Whether to use floating precision accuracy.

Return values

int|float

parse_key()

cache::parse_key (   $key )

protectedinherited

Parses the key turning it into a string (or array is required) suitable to be passed to the cache store.

Parameters

string | int

$key

As passed to get|set|delete etc.

Return values

string|array

String unless the store supports multi-identifiers in which case an array if returned.

Reimplemented in cache_session.

purge()

cache_disabled::purge

(

)

Purges all items from the cache.

Return values

bool

Reimplemented from cache.

requires_serialisation()

cache::requires_serialisation (   $value,   $depth = 1  )

protectedinherited

Checks to see if a var requires serialisation.

Parameters

mixed	$value	The value to check.
int	$depth	Used to ensure we don't enter an endless loop (think recursion).

Return values

bool	Returns true if the value is going to require serialisation in order to ensure a reference free copy or false if its safe to clone.

set()

cache_disabled::set	(		$key,
			$data
	)

Sets a key value pair in the cache.

Parameters

int | string	$key	Unused.
mixed	$data	Unused.

Return values

bool

Reimplemented from cache.

set_data_source()

cache::set_data_source ( cache_data_source  $datasource )

protectedinherited

Set the data source for this cache.

Parameters

cache_data_source

$datasource

set_identifiers()

cache::set_identifiers ( array  $identifiers )

inherited

Alters the identifiers that have been provided to the definition.

This is an advanced method and should not be used unless really needed. It allows the developer to slightly alter the definition without having to re-establish the cache. It will cause more processing as the definition will need to clear and reprepare some of its properties.

Parameters

array

$identifiers

set_in_persist_cache()

cache::set_in_persist_cache ( )

protectedinherited

Deprecated:

since 2.6

See also

cache::static_acceleration_set

set_is_sub_loader()

cache::set_is_sub_loader (   $setting = true )

protectedinherited

Used to inform the loader of its state as a sub loader, or as the top of the chain.

This is important as it ensures that we do not have more than one loader keeping static acceleration data. Subloaders need to be "pure" loaders in the sense that they are used to store and retrieve information from stores or the next loader/data source in the chain. Nothing fancy, nothing flash.

Parameters

bool

$setting

set_loader()

cache::set_loader ( cache_loader  $loader )

protectedinherited

Set the loader for this cache.

Parameters

cache_loader

$loader

set_many()

cache_disabled::set_many

(

array

$keyvaluearray

)

Sets many key value pairs in the cache at once.

Parameters

array

$keyvaluearray

Unused.

Return values

int

Reimplemented from cache.

static_acceleration_delete()

cache::static_acceleration_delete (   $key )

protectedinherited

Deletes an item from the static acceleration array.

Parameters

string | int

$key

As given to get|set|delete

Return values

bool	True on success, false otherwise.

static_acceleration_get()

cache::static_acceleration_get (   $key )

protectedinherited

Returns the item from the static acceleration array if it exists there.

Parameters

string

$key

The parsed key

Return values

mixed|false

Dereferenced data from the static acceleration array or false if it wasn't there.

static_acceleration_has()

cache::static_acceleration_has (   $key )

protectedinherited

Returns true if the requested key exists within the static acceleration array.

Parameters

string

$key

The parsed key

Return values

bool

static_acceleration_set()

cache::static_acceleration_set (   $key,   $data  )

protectedinherited

Sets a key value pair into the static acceleration array.

Parameters

string	$key	The parsed key
mixed	$data

Return values

bool

store_supports_key_awareness()

cache::store_supports_key_awareness ( )

protectedinherited

Returns true if the store supports key awareness.

Return values

bool

store_supports_native_locking()

cache::store_supports_native_locking ( )

protectedinherited

Returns true if the store natively supports locking.

Return values

bool

store_supports_native_ttl()

cache::store_supports_native_ttl ( )

protectedinherited

Returns true if the cache store supports native ttl.

Return values

bool

unref()

cache::unref (   $data )

protectedinherited

Removes references where required.

Parameters

stdClass | array

$data

Return values

mixed

What ever was put in but without any references.

use_static_acceleration()

cache::use_static_acceleration ( )

protectedinherited

Returns true if this cache is making use of the static acceleration array.

Return values

bool

Reimplemented in cache_session.

Member Data Documentation

$now

int cache::$now

staticprotectedinherited

We need a timestamp to use within the cache API.

This stamp needs to be used for all ttl and time based operations to ensure that we don't end up with timing issues.

$purgetoken

string cache::$purgetoken

staticprotectedinherited

A purge token used to distinguish between multiple cache purges in the same second.

This is in the format <microtime>-<random string>.

$storetype

strubg cache::$storetype = 'unknown'

protectedinherited

Gets set to the class name of the store during initialisation.

This is used several times in the cache class internally and having it here helps speed up processing.

---

The documentation for this class was generated from the following file:

• cache/disabledlib.php