EBernhardson has uploaded a new change for review.
https://gerrit.wikimedia.org/r/119079
Change subject: Join ObjectStorage and WritableObjectStorage interfaces
......................................................................
Join ObjectStorage and WritableObjectStorage interfaces
We had ObjectLocator (base ObjectManager class) and DbStorage (backend storage)
implementing the same ObjectStorage interface, this doesn't really make sense
as the query options are different, additionally backend returns rows and
the frontend returns domain models. This is basically a violation of LSP.
Make ObjectLocator no longer implement a particular interface, merge
WritableObjectStorage and ObjectStorage, and make DbStorage implement
ObjectStorage.
Also updated a few class comments.
Change-Id: I9962ff4b4e4aa42d2d5e210eab333bbbfcf2e754
---
M includes/Data/ObjectManager.php
1 file changed, 58 insertions(+), 34 deletions(-)
git pull ssh://gerrit.wikimedia.org:29418/mediawiki/extensions/Flow
refs/changes/79/119079/1
diff --git a/includes/Data/ObjectManager.php b/includes/Data/ObjectManager.php
index 761a5e1..ae53501 100644
--- a/includes/Data/ObjectManager.php
+++ b/includes/Data/ObjectManager.php
@@ -13,13 +13,10 @@
use Flow\Exception\DataPersistenceException;
use Flow\Exception\NoIndexException;
-// Perhaps rethink lifecycle interface. Simpler.
-// Indexes need access to the cache and the backend storage.
-// It seems likely different Indexes could use different caches
(redis/memcache)
-// - But we want to be able to replace that cache with a buffered cache that
flushes
-// on db commit.
-// - Perhaps one buffered cache could wrap both redis and memcache? seems odd
though
-
+/**
+ * Listeners that receive notifications about the lifecycle of
+ * a domain model.
+ */
interface LifecycleHandler {
function onAfterLoad( $object, array $old );
function onAfterInsert( $object, array $new );
@@ -27,45 +24,72 @@
function onAfterRemove( $object, array $old );
}
-// Some denormalized data doesnt accept writes, it merely triggers cache
updates
-// when something else does the write. Indexes are the primary use case.
-// IteratorAggregate rather than traversable to simplify nested implementations
-interface ObjectStorage extends \IteratorAggregate {
- function find( array $attributes, array $options = array() );
+/**
+ * Interface representing backend data stores. Typically they
+ * will be implemented in SQL with the DbStorage base class.
+ */
+interface ObjectStorage {
+
/**
- * The BagOStuff interface returns with keys matching the key,
unfortunately
- * we deal with composite keys which makes that awkward. Instead all
findMulti
- * implementations must return their result as if it was array_map(
array( $obj, 'find' ), $queries ).
- * This is necessary so result sets stay ordered
+ * Perform a single equality query.
*
+ * @param array $attributes Map of attributes the model must contain
+ * @param array $options Query options such as ORDER BY and LIMIT.
+ * @return array
+ */
+ function find( array $attributes, array $options = array() );
+
+ /**
+ * Perform the equivilent of array_map against self::find for multiple
+ * equality queries with the minimum of network round trips.
*
* @param array $queries list of queries to perform
* @param array $options Options to use for all queries
* @return array
*/
function findMulti( array $queries, array $options = array() );
- function getPrimaryKeyColumns();
- // Clear any information stored about loaded objects
- // This interface is used by the frontend (ObjectLocator) and the
backend (BasicDbStorage, etc)
- //function clear();
-}
-// Backing stores, typically in SQL
-// Note that while ObjectLocator implements the above ObjectStorage interface,
ObjectManger
-// cant use this interface because backing stores deal in rows, and OM deals
in objects.
-interface WritableObjectStorage extends ObjectStorage {
/**
- * @param array $row
- * @return array The resulting $row including any auto-assigned ids or
false on failure
+ * @return array The list of columns that together uniquely identify a
row
+ */
+ function getPrimaryKeyColumns();
+
+ /**
+ * Insert the specified row into the data store.
+ *
+ * @param array $row Map of columns to values
+ * @return array|false The resulting $row including any auto-assigned
ids or false on failure
*/
function insert( array $row );
+
+ /**
+ * Perform all changes necessary to turn $old into $new in the data
store.
+ *
+ * @param array $old Map of columns to values that was initially loaded.
+ * @param array $new Map of columns to values that the row should
become.
+ * @return boolean true when the row is successfully updated
+ */
function update( array $old, array $new );
+
+ /**
+ * Remove the specified row from the data store.
+ *
+ * @param array $row Map of columns to values. Must contain the
primary key columns.
+ * @return boolean true when the row is successfully removed
+ */
function remove( array $row );
}
+/**
+ * Interface for converting back and forth between a database row and
+ * a domain model.
+ */
interface ObjectMapper {
/**
* Convert $object from the domain model to its db row
+ *
+ * @param object $object
+ * @return array
*/
function toStorageRow( $object );
@@ -159,9 +183,10 @@
*/
function compareRowToOffset( $row, $offset );
}
+
/**
- * Compact rows before writing to memcache, expand when receiving back
- * Still returns arrays, just removes unneccessary values
+ * Compact rows before writing to cache, expand when receiving back
+ * Still returns arrays, just removes unneccessary values.
*/
interface Compactor {
/**
@@ -185,7 +210,6 @@
*/
public function expandCacheResult( array $cached, array $keyToQuery );
}
-
/**
* A little glue code to allow passing around and manipulating multiple
@@ -254,7 +278,7 @@
* update events.
* Error handling is all wrong, but simplifies prototyping.
*/
-class ObjectLocator implements ObjectStorage {
+class ObjectLocator {
/*
* @var ObjectMapper
*/
@@ -556,7 +580,7 @@
// @var SplObjectStorage $loaded If the object exists then an 'update'
is issued, otherwise 'insert'
protected $loaded;
- public function __construct( ObjectMapper $mapper,
WritableObjectStorage $storage, array $indexes = array(), array
$lifecycleHandlers = array() ) {
+ public function __construct( ObjectMapper $mapper, ObjectStorage
$storage, array $indexes = array(), array $lifecycleHandlers = array() ) {
parent::__construct( $mapper, $storage, $indexes,
$lifecycleHandlers );
// This needs to be SplObjectStorage rather than using
spl_object_hash for keys
@@ -742,13 +766,13 @@
}
/**
- * Base class for all WritableObjectStorage implementers
+ * Base class for all ObjectStorage implementers
* which use a database as the backing store.
*
* Includes some utility methods for database management and
* SQL security.
*/
-abstract class DbStorage implements WritableObjectStorage {
+abstract class DbStorage implements ObjectStorage {
protected $dbFactory;
public function __construct( DbFactory $dbFactory ) {
--
To view, visit https://gerrit.wikimedia.org/r/119079
To unsubscribe, visit https://gerrit.wikimedia.org/r/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: I9962ff4b4e4aa42d2d5e210eab333bbbfcf2e754
Gerrit-PatchSet: 1
Gerrit-Project: mediawiki/extensions/Flow
Gerrit-Branch: master
Gerrit-Owner: EBernhardson <[email protected]>
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