SnapCache Class Reference
[Core]

Cache manager for Snap2. More...

Inheritance diagram for SnapCache:

List of all members.

Static Public Member Functions

static clearObjectCache ($name)

INSERT BRIEF DESCRIPTION HERE.

static deleteById ($type, $id)

Remove object from cache by ID.

static deleteByPath ($type, $path)

Removes object from cache via its path.

static dumpCache ()

Displays detailed cache information in the debug message queue.

static getById ($type, $id)

Retrieve Snap object from cache by ID.

static getByPath ($type, $path)

Retrieves object from cache by path.

static getObjectCache ($name)

INSERT BRIEF DESCRIPTION HERE.

static getPathsById ($type, $id)

Retrieves all paths in cache for object with given ID.

static init ($useCache=true, $useApc=true)

Initializes the cache manager.

static putById ($type, $id, $obj)

Puts a Snap object in the cache, identified by ID.

static putByPath ($type, $path, $obj, $isCanon=false)

Put object into path cache.

static setEnableAPC ($enable, $clear=false)

Enables/disables usage of the APC cache.

static setEnableCache ($enable, $clear=false)

Enables/disables the plain old cache.

static showStats ()

Displays cache statistics in the debug message queue.

static updateById ($type, $id)

Update object in cache.

static usingApc ()

Returns whether APC is currently enabled.

static usingCache ()

Returnes whether plain cache is in use.

Static Private Attributes

static $APC_EXISTS

static $CACHE_ID

static $CACHE_PATH

static $ID_CACHE_HITS

static $ID_CACHE_MISSES

static $ID_TO_PATH

static $PATH_CACHE_HITS

static $PATH_CACHE_MISSES

static $TYPE_MAP

static $useApc

static $useCache

Detailed Description

Cache manager for Snap2.

For internal use only.

The cache stores Snap objects for the duration of a script's execution, with the goal of improving performance. The cache manager can also store objects in the APC cache, so that they continue to exist even after the script exits and can be used by future runs of the script. Currently, the APC cache is broken and is disabled by default. Do not enable it if you plan to have non-corrupt data.

Users of the Snap2 API should not use this class directly. Cache management features are available from the Snap2 management class.

Definition at line 17 of file SnapCache.php5.

Member Function Documentation

static SnapCache::clearObjectCache ( $ name ) [static]

INSERT BRIEF DESCRIPTION HERE.

INSERT FULL DESCRIPTION HERE

Parameters:

$name

[TYPE]: DESCRIPTION

Returns:: [TYPE]: RETURN DESCRIPTION

Definition at line 332 of file SnapCache.php5.

Referenced by SnapPermission::commit(), SnapPermission::grantPrivilege(), and SnapPermission::revokePrivilege().

static SnapCache::deleteById	(	$	type,
		$	id
	)			`[static]`

Remove object from cache by ID.

For internal use only.

Also removes entries in path cache that point to the same object. Object is not actually "deleted", however.

Parameters:

	$type	[string]: type of object to delete (e.g., 'Directory')
	$id	[mixed]: ID of object to delete

Definition at line 187 of file SnapCache.php5.

static SnapCache::deleteByPath	(	$	type,
		$	path
	)			`[static]`

Removes object from cache via its path.

For internal use only.

This method does not remove other paths to the object in the cache, or the ID cache entry.

Parameters:

	$type	[string]: type of object to remove from path cache (e.g., 'Directory', etc.)
	$path	[string]: path of object

Definition at line 286 of file SnapCache.php5.

static SnapCache::dumpCache ( ) [static]

Displays detailed cache information in the debug message queue.

For internal use only.

Definition at line 387 of file SnapCache.php5.

References SErrorManager::setDebug().

static SnapCache::getById	(	$	type,
		$	id
	)			`[static]`

Retrieve Snap object from cache by ID.

For internal use only.

If object is not in cache, and APC is enabled, then APC is consulted to retrieve the object, which is then put in the regular cache and returned. If object is not in cache or APC, then null is returned.

Parameters:

	$type	[string]: type of object to retrieve (e.g., 'Directory', etc.)
	$id	[mixed]: ID of object to retrieve

Returns:: [SnapObject]: object from cache, or null if cache miss

Definition at line 159 of file SnapCache.php5.

Referenced by SnapDirectory::listContents(), SnapFile::loadMetadata(), SnapFile::loadPermission(), SnapResourceUserPermission::retrieve(), SnapResourceGroupPermission::retrieve(), SnapDirectoryUserPermission::retrieve(), SnapDirectoryGroupPermission::retrieve(), SnapVersion::retrieve(), SnapResource::retrieve(), SnapDirectory::retrieve(), and SnapPermissionObject::warmCache().

static SnapCache::getByPath	(	$	type,
		$	path
	)			`[static]`

Retrieves object from cache by path.

For internal use only.

If no object is found in the cache by the given path, then APC is consulted. If there is an object in APC for the path, then it is put in the regular cache. If it is not in APC or the regular cache, null is returned.

Parameters:

	$type	[string]: type of object to retrieve from cache (e.g., 'Directory', etc.)
	$path	[string]: path by which to retrieve object

Returns:: [SnapObject]: object from cache or null if not in cache

Definition at line 234 of file SnapCache.php5.

Referenced by SnapVersion::lookup(), SnapResource::lookup(), and SnapDirectory::lookup().

static SnapCache::getObjectCache ( $ name ) [static]

INSERT BRIEF DESCRIPTION HERE.

INSERT FULL DESCRIPTION HERE

Parameters:

$name

[TYPE]: DESCRIPTION

Returns:: [TYPE]: RETURN DESCRIPTION

Definition at line 346 of file SnapCache.php5.

Referenced by SnapPermission::commit(), SnapPermission::grantPrivilege(), and SnapPermission::revokePrivilege().

static SnapCache::getPathsById	(	$	type,
		$	id
	)			`[static]`

Retrieves all paths in cache for object with given ID.

For internal use only.

Parameters:

	$type	[string]: type of object to retrieve (e.g., 'Directory', etc.)
	$id	[mixed]: ID of object to retrieve paths for

Returns:: [array]: array of all paths in cache for object, or null of object not found in cache

Definition at line 266 of file SnapCache.php5.

Referenced by SnapFile::loadCanonicalPath().

static SnapCache::init	(	$	useCache = `true`,
		$	useApc = `true`
	)			`[static]`

Initializes the cache manager.

For internal use only.

This method should only be called by Snap2::init.

Parameters:

	$useCache	[boolean]: whether to use the plain cache
	$useApc	[boolean]: whether to use the APC cache

Definition at line 68 of file SnapCache.php5.

References $useApc, and $useCache.

Referenced by Snap2::init(), and Snap2::reinit().

static SnapCache::putById	(	$	type,
		$	id,
		$	obj
	)			`[static]`

Puts a Snap object in the cache, identified by ID.

For internal use only.

Use updatebyId() if object is already in the cache. This method will perform a write-through to APC if use of the APC cache is enabled.

Parameters:

	$type	[string]: object type (e.g., 'Directory', etc.)
	$id	[mixed]: ID of object
	$obj	[SnapObject]: actual object

Definition at line 139 of file SnapCache.php5.

Referenced by SnapDirectory::createDirectory(), SnapDirectory::createResource(), SnapDirectory::listContents(), SnapFile::loadMetadata(), SnapFile::loadPermission(), SnapResourceUserPermission::retrieve(), SnapResourceGroupPermission::retrieve(), SnapDirectoryUserPermission::retrieve(), SnapDirectoryGroupPermission::retrieve(), SnapVersion::retrieve(), SnapResource::retrieve(), SnapDirectory::retrieve(), and SnapPermissionObject::warmCache().

static SnapCache::putByPath	(	$	type,
		$	path,
		$	obj,
		$	isCanon = `false`
	)			`[static]`

Put object into path cache.

For internal use only.

In addition to putting the object in the path cache, it also puts the object in the regular ID-based cache. You can also specify if the path is the canonical path of the object, so that canonical path lookups will be faster.

Parameters:

	$type	[string]: type of object (e.g., 'Directory', etc.)
	$path	[string]: Snap path
	$obj	[SnapObject]: object to put into the cache
	$isCanon	[boolean]: whether $path is the canonical path to the object

Definition at line 209 of file SnapCache.php5.

Referenced by SnapDirectory::listContents(), and SnapFile::loadCanonicalPath().

static SnapCache::setEnableAPC	(	$	enable,
		$	clear = `false`
	)			`[static]`

Enables/disables usage of the APC cache.

For internal use only.

Call Snap2::setEnableAPC() instead (which just calls this method, but does some other things as well).

Parameters:

	$enable	[boolean]: whether to enable APC cache
	$clear	[boolean]: whether to clear out the existing entries in the APC cache if disabling

Definition at line 84 of file SnapCache.php5.

Referenced by Snap2::setEnableAPC().

static SnapCache::setEnableCache	(	$	enable,
		$	clear = `false`
	)			`[static]`

Enables/disables the plain old cache.

Call Snap2::setEnableCache() instead (which calls this method, but does some other things as well).

Parameters:

	$enable	[boolean]: whether to enable to cache
	$clear	[boolean]: whether to clear out the cache if disabling

Definition at line 108 of file SnapCache.php5.

Referenced by SnapPermission::commit(), and Snap2::setEnableCache().

static SnapCache::showStats ( ) [static]

Displays cache statistics in the debug message queue.

For internal use only.

Definition at line 355 of file SnapCache.php5.

References SErrorManager::setDebug().

static SnapCache::updateById	(	$	type,
		$	id
	)			`[static]`

Update object in cache.

For internal use only.

This method only exists because APC caching is currently write-through, not write-back or write-combining, so we need to explicitly have an object written to the APC cache when it is changed, or it won't be properly stored. Call this method whenever an object changes.

Parameters:

	$type	[string]: object type (e.g., 'Directory', etc.)
	$id	[mixed]: ID of object

Definition at line 309 of file SnapCache.php5.

Referenced by SnapMetadata::commit(), SnapResource::loadActiveVersion(), SnapFile::loadCanonicalParent(), SnapFile::loadCanonicalPath(), SnapVersion::loadContentModule(), SnapResource::loadDevVersion(), SnapResource::loadLiveVersion(), SnapDirectory::loadMaxDirOrdinal(), SnapResource::loadMaxOrdinal(), SnapDirectory::loadMaxResOrdinal(), SnapFile::loadMetadata(), SnapFile::loadPermission(), SnapVersion::loadPrevVersion(), SnapVersion::loadResource(), SnapVersion::populate(), SnapMetadata::populate(), SnapFile::populate(), and SnapFile::restore().

static SnapCache::usingApc ( ) [static]

Returns whether APC is currently enabled.

Returns:: [boolean]: whether APC is enabled

Definition at line 97 of file SnapCache.php5.

static SnapCache::usingCache ( ) [static]

Returnes whether plain cache is in use.

Returns:: [boolean]: whether plain cache is in use

Definition at line 125 of file SnapCache.php5.

Referenced by SnapPermission::commit().

Member Data Documentation

SnapCache::$APC_EXISTS [static, private]

Whether we can even use APC (in case the extension is disabled)

Definition at line 46 of file SnapCache.php5.

SnapCache::$CACHE_ID [static, private]

ID cache: cache objects by their type and ID

Definition at line 19 of file SnapCache.php5.

SnapCache::$CACHE_PATH [static, private]

Path cache: cache objects by their type and path

Definition at line 29 of file SnapCache.php5.

SnapCache::$ID_CACHE_HITS [static, private]

Number of times ID cache was consulted and the object was found in cache

Definition at line 34 of file SnapCache.php5.

SnapCache::$ID_CACHE_MISSES [static, private]

Number of times ID cache was consulted and object was not in cache

Definition at line 32 of file SnapCache.php5.

SnapCache::$ID_TO_PATH [static, private]

Relates object IDs to entries in the path cache

Definition at line 27 of file SnapCache.php5.

SnapCache::$PATH_CACHE_HITS [static, private]

Number of times path cache was consulted and the object was found in cache

Definition at line 38 of file SnapCache.php5.

SnapCache::$PATH_CACHE_MISSES [static, private]

Number of times path cache was consulted and object was not in cache

Definition at line 36 of file SnapCache.php5.

SnapCache::$TYPE_MAP [static, private]

Used to generate APC cache keys; instead of 'Directory' we'd use 'D', etc.

Definition at line 49 of file SnapCache.php5.

SnapCache::$useApc [static, private]

Whether the APC cache is in use

Definition at line 41 of file SnapCache.php5.

Referenced by init().

SnapCache::$useCache [static, private]

Whether the plain old cache is in use

Definition at line 43 of file SnapCache.php5.

Referenced by init().

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

snap2/core/SnapCache.php5


Static Public Member Functions
static	clearObjectCache ($name)
	INSERT BRIEF DESCRIPTION HERE.
static	deleteById ($type, $id)
	Remove object from cache by ID.
static	deleteByPath ($type, $path)
	Removes object from cache via its path.
static	dumpCache ()
	Displays detailed cache information in the debug message queue.
static	getById ($type, $id)
	Retrieve Snap object from cache by ID.
static	getByPath ($type, $path)
	Retrieves object from cache by path.
static	getObjectCache ($name)
	INSERT BRIEF DESCRIPTION HERE.
static	getPathsById ($type, $id)
	Retrieves all paths in cache for object with given ID.
static	init ($useCache=true, $useApc=true)
	Initializes the cache manager.
static	putById ($type, $id, $obj)
	Puts a Snap object in the cache, identified by ID.
static	putByPath ($type, $path, $obj, $isCanon=false)
	Put object into path cache.
static	setEnableAPC ($enable, $clear=false)
	Enables/disables usage of the APC cache.
static	setEnableCache ($enable, $clear=false)
	Enables/disables the plain old cache.
static	showStats ()
	Displays cache statistics in the debug message queue.
static	updateById ($type, $id)
	Update object in cache.
static	usingApc ()
	Returns whether APC is currently enabled.
static	usingCache ()
	Returnes whether plain cache is in use.
Static Private Attributes
static	$APC_EXISTS
static	$CACHE_ID
static	$CACHE_PATH
static	$ID_CACHE_HITS
static	$ID_CACHE_MISSES
static	$ID_TO_PATH
static	$PATH_CACHE_HITS
static	$PATH_CACHE_MISSES
static	$TYPE_MAP
static	$useApc
static	$useCache

SnapCache Class Reference [Core]

Static Public Member Functions

Static Private Attributes

Detailed Description

Member Function Documentation

Member Data Documentation

SnapCache Class Reference
[Core]