Introduced settings sources and formats

A `SettingsSource` is meant to represent any kind of local or remote
store from which settings can be read, be this a local file, remote URL,
database, etc. It is concerned with reading in (and possibly decoding)
settings data, and computing a consistent hash key that may be used in
caching.

A `SettingsFormat` is meant to detect supported file types and/or decode
source contents into settings arrays. As of now, JSON is the only
supported format but others may be implemented.

`FileSource` is the first source implementation, with its default format
being JSON, meant to read settings from local JSON files.

`ArraySource` is mostly useful for testing using array literals.

Refactored `SettingsBuilder` methods to use the new source abstractions.

Bug: T295499
Change-Id: If7869609c4ad1ccd0894d5ba358f885007168972

1 files changed, 25 insertions, 0 deletions

diff --git a/includes/Settings/Source/ArraySource.php b/includes/Settings/Source/ArraySource.php
new file mode 100644
index 000000000000..a7a1cdfbf66f
--- /dev/null
+++ b/includes/Settings/Source/ArraySource.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace MediaWiki\Settings\Source;
+
+/**
+ * Settings loaded from an array.
+ *
+ * @since 1.38
+ */
+class ArraySource implements SettingsSource {
+
+	private $settings;
+
+	public function __construct( array $settings ) {
+		$this->settings = $settings;
+	}
+
+	public function load(): array {
+		return $this->settings;
+	}
+
+	public function __toString(): string {
+		return '<array>';
+	}
+}