Convert DrupalCacheArray and SchemaCache to PSR-0

DrupalCacheArray itself I don't think belongs in the cache subsystem (at the moment it has a cross-dependency on the lock system for a start), and feels more like a standalone to me.

The Schema class should go in the Drupal\Core\Schema namespace, except we'd need to convert the schema API to classes first. There may be an issue for that already.

Agreed with catch. DrupalCacheArray should be its own thing, and we should try to remove those dependencies if possible (or inject them). For schema... Overhauling the Schema API to be more consistent and modern is on my todo list, but so are many other things. :-/

Perhaps we should have a Drupal\Core\Utility for these one-off little classes for the time being, so they don't pollute Drupal\Core if they have nowhere else to go.

There's an issue for lock.inc at #1225404: Modern event based lock framework proposal however it's gone quite a bit further than a straight OOP-ifying, so I'm wondering if we need a new issue for a straight-as-possible conversion to unblock the general detangling issues such as this.

+++ b/core/lib/Drupal/Core/Utilities/DrupalCacheArray.php
@@ -0,0 +1,202 @@
+<?php
+namespace Drupal\Core\Utilities;
+use \ArrayAccess;

Missing @file doc block: http://drupal.org/node/1354#files

Also, missing blank line between the namespace declaration and the use statement, and I think we decided against using "\" in front of class names.

For inspiration, you can take a look at a class that has already been converted, like http://drupalcode.org/project/drupal.git/blob/refs/heads/8.x:/core/lib/D...

+++ b/core/lib/Drupal/Core/Utilities/DrupalCacheArray.php
@@ -0,0 +1,202 @@
+abstract class DrupalCacheArray implements ArrayAccess {

I think we need to drop 'Drupal' and rename to CacheArray.

+++ b/core/lib/Drupal/Core/Utilities/DrupalCacheArray.php
@@ -0,0 +1,202 @@
\ No newline at end of file

+++ b/core/lib/Drupal/Core/Utilities/SchemaCache.php
@@ -0,0 +1,28 @@
\ No newline at end of file

Meh :)

This looks good to me now. I think we'll eventually want to move the schema cache stuff into the schema namespace, but that can wait on having actual code existing there.

There's not really a problem extending classes in different namespaces as far as I'm concerned - it just shows the various dependencies for what they are.

I think we're using singular namespaces, not plural, so it should be Drupal\Core\Utility, not Drupal\Core\Utilities. Other than that, this looks done.

Partially agreed with catch. Inheriting from an out-of-namespace class isn't a bad thing. However, if you're inheriting back and forth like a madman between two namespaces, it is a code smell that maybe they should be the same namespace/package.

Either way, fix the pluralization here and I think we're good to go.

And I second that.

Committed/pushed to 8.x, thanks!