Spacing support: Add server-side support for margins

lib/block-supports/spacing.php

@@ -0,0 +1,85 @@
+<?php
+/**
+ * Spacing block support flag.
+ *
+ * @package gutenberg
+ */
+
+/**
+ * Registers the style block attribute for block types that support it.
+ *
+ * @param WP_Block_Type $block_type Block Type.
+ */
+function gutenberg_register_spacing_support( $block_type ) {
+	$has_spacing_support = gutenberg_block_has_support( $block_type, array( 'spacing' ), false );
+
+	// Setup attributes and styles within that if needed.
+	if ( ! $block_type->attributes ) {
+		$block_type->attributes = array();
+	}
+
+	if ( $has_spacing_support && ! array_key_exists( 'style', $block_type->attributes ) ) {
+		$block_type->attributes['style'] = array(
+			'type' => 'object',
+		);
+	}
+}
+
+/**
+ * Add CSS classes for block spacing to the incoming attributes array.
+ * This will be applied to the block markup in the front-end.
+ *
+ * @param WP_Block_Type $block_type       Block Type.
+ * @param array         $block_attributes Block attributes.
+ *
+ * @return array Block spacing CSS classes and inline styles.
+ */
+function gutenberg_apply_spacing_support( $block_type, $block_attributes ) {
+	$has_padding_support = gutenberg_has_spacing_feature_support( $block_type, 'padding' );
+	$has_margin_support  = gutenberg_has_spacing_feature_support( $block_type, 'margin' );
+	$styles              = array();
+
+	if ( $has_padding_support ) {
+		$padding_value = _wp_array_get( $block_attributes, array( 'style', 'spacing', 'padding' ), null );
+		if ( null !== $padding_value ) {
+			foreach ( $padding_value as $key => $value ) {
+				$styles[] = sprintf( 'padding-%s: %s;', $key, $value );
+			}
+		}
+	}
+
+	if ( $has_margin_support ) {
+		$margin_value = _wp_array_get( $block_attributes, array( 'style', 'spacing', 'margin' ), null );
+		if ( null !== $margin_value ) {
+			foreach ( $margin_value as $key => $value ) {
+				$styles[] = sprintf( 'margin-%s: %s;', $key, $value );
+			}
+		}
+	}
+
+	return empty( $styles ) ? array() : array( 'style' => implode( ' ', $styles ) );
+}
+
+/**
+ * Checks whether the current block type supports the spacing feature requested.
+ *
+ * @param WP_Block_Type $block_type Block type to check for support.
+ * @param string        $feature    Name of the feature to check support for.
+ * @param mixed         $default    Fallback value for feature support, defaults to false.
+ *
+ * @return boolean                  Whether or not the feature is supported.
+ */
+function gutenberg_has_spacing_feature_support( $block_type, $feature, $default = false ) {
+	// Check if the specific feature has been opted into individually
+	// via nested flag under `spacing`.
+	return gutenberg_block_has_support( $block_type, array( 'spacing', $feature ), $default );
+}
+
+// Register the block support.
+WP_Block_Supports::get_instance()->register(
+	'spacing',
+	array(
+		'register_attribute' => 'gutenberg_register_spacing_support',
+		'apply'              => 'gutenberg_apply_spacing_support',
+	)
+);

lib/load.php

@@ -129,5 +129,5 @@ function gutenberg_is_experiment_enabled( $name ) {
 require __DIR__ . '/block-supports/custom-classname.php';
 require __DIR__ . '/block-supports/border.php';
 require __DIR__ . '/block-supports/layout.php';
-require __DIR__ . '/block-supports/padding.php';
+require __DIR__ . '/block-supports/spacing.php';
 require __DIR__ . '/block-supports/duotone.php';