<?php
/**
* WP_View_Config_Data class
*
* @package WordPress
* @since 7.1.0
*/
/**
* Holds an entity's view configuration while it is being built.
*
* An instance of this class is what `get_entity_view_config_{$kind}_{$name}`
* filter callbacks receive: a callback changes the configuration by calling
* methods on the instance and returning it. The configuration has four
* top-level keys — `default_view`, `default_layouts`, `view_list`, and
* `form` — and there are three ways to contribute. They form a gradient of how
* deep the replacement reaches:
*
* - The `merge()` method merges partial changes (patches) into what is already
* there: `default_view`, `default_layouts`, and the `form` settings by key,
* and the `view_list` entries by view `slug` identity. This is what plugins
* should use: patches compose with core's configuration and with other
* plugins'.
* - `replace()` applies a patch the same way `merge()` does, with one
* difference: a list in the patch replaces the current list wholesale
* instead of merging into it by member identity. It shouldn't be the
* default choice — a callback that replaces a list stops inheriting core's
* future additions to it — but it's useful when a contributor needs to pin
* a list to an exact set of members.
* - `set()` goes one step further: it replaces each top-level key the patch
* names wholesale, dropping whatever that key held instead of merging into
* it. It's for a callback that owns a key outright and wants to pin it to an
* exact shape without the inherited default leaking through a key-by-key
* merge.
*
* All three touch only the top-level keys the patch names — an omitted key
* keeps whatever it had, and a top-level `null` value drops the key it names,
* which resets it to its default. They differ only in how deep the replacement
* reaches once a key is named: `merge()` and `replace()` merge the value in
* key by key (an associative array merges member by member, a nested `null`
* deletes just that leaf, a scalar replaces just that value), while `set()`
* swaps the whole value. A nested `null` deletes just the leaf it names in
* every case. A patch value whose shape does not match the current value —
* an associative array where a list lives, or the reverse — is rejected with
* a notice rather than merged, and an empty array under `merge()` is a
* no-op. Each patch also declares the configuration schema
* version it was written against (currently 1), so a future WordPress release
* that changes the configuration shape can migrate existing patches forward
* instead of breaking them.
*
* Where those three write values, `remove()` deletes them: it takes a spec of
* names — a list to delete entries at a level, or a nested map to reach deeper —
* and prunes just what it names, mirroring the configuration's shape all the way
* down to individual list members.
*
* @since 7.1.0
*/
class WP_View_Config_Data {
/**
* The latest supported configuration schema version.
*
* @since 7.1.0
* @var int
*/
const LATEST_VERSION = 1;
/**
* The documented top-level configuration keys.
*
* @since 7.1.0
* @var string[]
*/
const CONFIG_KEYS = array( 'default_view', 'default_layouts', 'view_list', 'form' );
/**
* The configuration being contributed to.
*
* @since 7.1.0
* @var array
*/
private $config;
/**
* The default configuration.
*
* @since 7.1.0
* @var array
*/
private $defaults;
/**
* Constructor.
*
* @since 7.1.0
*
* @param array $config The base configuration to contribute to.
*/
public function __construct( array $config ) {
$this->config = $config;
$this->defaults = $config;
}
/**
* Returns the current configuration array.
*
* Deliberately private: filter callbacks receive the container, not the
* materialized configuration, so they cannot read the built result and
* become coupled to a specific configuration shape or schema version. Only
* the class itself reconciles the container back into an array.
*
* @since 7.1.0
*
* @return array The configuration.
*/
private function get_data() {
return $this->config;
}
/**
* Applies the entity view configuration filter and returns the result.
*
* Exposes the container through the dynamic
* `get_entity_view_config_{$kind}_{$name}` filter (with the dynamic portions
* lowercased), so that core and third parties can provide the configuration for a specific entity,
* then reconciles the filtered container back into a plain configuration array,
* limited to the documented configuration keys.
*
* @since 7.1.0
*
* @param string $kind The entity kind (e.g. `postType`).
* @param string $name The entity name (e.g. `page`).
* @return array The filtered configuration, limited to the documented keys.
*/
public function apply_filters( $kind, $name ) {
/**
* Filters the view configuration for a given entity.
*
* The dynamic portions of the hook name, `$kind` and `$name`, refer to the
* entity kind (e.g. `postType`) and the entity name (e.g. `page`),
* lowercased — so the `postType`/`page` entity maps to the
* `get_entity_view_config_posttype_page` hook.
*
* Callbacks receive a WP_View_Config_Data object and change the
* configuration through its methods. Each write method takes the schema
* version the change was authored against as its second argument,
* and returns the object for chaining:
*
* - `merge( $patch, $version )` merges a partial change into the current
* configuration. It touches only the top-level keys the patch names, and
* merges each named value into the current one by shape: a scalar
* replaces, an associative array merges key by key, and a list merges by
* member identity (`id`, `slug`, or `field`). A `null` value drops the
* key it names, resetting it to its default.
* - `replace( $patch, $version )` applies a patch exactly like `merge()`,
* but swaps any list it names wholesale instead of merging that list by
* member identity.
* - `set( $patch, $version )` also touches only the keys the patch names,
* but swaps each named value in wholesale, dropping whatever the key held
* before — for a callback that owns those keys outright.
* - `remove( $spec, $version )` deletes named properties. The spec mirrors
* the configuration shape: a list of names deletes entries at that level,
* and a nested map recurses to prune from within a named value, down to
* individual list members.
*
* A change that declares an unsupported schema version is rejected and does
* not alter anything. As with any filter, each callback's return value is
* passed to the next callback as `$data`, so callbacks must return the
* container they received: a callback that returns nothing, or any other
* value, hands that result to every callback hooked at a later priority
* instead of the container. Since the write methods return the container,
* a callback can end with `return $data->merge( $patch, $version );`.
*
* @since 7.1.0
*
* @param WP_View_Config_Data $data The view configuration container
* for the entity, exposing the
* `default_view`, `default_layouts`,
* `view_list`, and `form` keys.
* @param array $entity {
* The entity the configuration is built for.
*
* @type string $kind The entity kind.
* @type string $name The entity name.
* }
*/
apply_filters(
wp_get_entity_view_config_hook_name( $kind, $name ),
$this,
array(
'kind' => $kind,
'name' => $name,
)
);
// Discard any keys the filter introduced that are not part of the
// documented configuration shape.
return array_intersect_key( $this->get_data(), array_flip( self::CONFIG_KEYS ) );
}
/**
* Replaces whole top-level keys, leaving the rest of the configuration alone.
*
* Like merge() and replace(), set() applies a patch of top-level keys and
* touches only the keys the patch names: a key the patch omits keeps whatever
* it had, and a `null` value drops the key it names (which resets it to its
* default). The difference is depth — where merge() and replace() merge a
* named key's value into the current one key by key, set() swaps the whole
* value in wholesale, dropping whatever the key held before. A `null` nested
* within that value still drops the property it names, so set() honours
* nulls at every depth just as merge() and replace() do.
*
* Use it when a callback owns a key outright and wants to pin it to an exact
* shape, without the inherited default leaking through a key-by-key merge.
*
* A patch that declares an unsupported schema version is rejected and does
* not change anything.
*
* @since 7.1.0
*
* @param array $patch The partial configuration whose named keys to replace.
* @param int $version The schema version the patch was authored against.
* @return WP_View_Config_Data The instance, for chaining.
*/
public function set( array $patch, int $version ) {
return $this->apply( $patch, $version, __METHOD__, 'set' );
}
/**
* Removes named properties from the configuration, leaving the rest alone.
*
* Where merge(), replace(), and set() take a patch of *values* to write,
* remove() takes a spec of *names* to delete, and its shape mirrors the
* configuration it prunes:
*
* - A list of names deletes each named entry from the value at that level: a
* key from an associative array, or the member with a matching identity
* (`id`, `slug`, `field`, or a bare scalar) from a list.
* - An associative array maps a name to a nested spec, recursing into that
* entry's value to delete from within it.
*
* Naming a top-level configuration key is the one exception: like a `null`
* value in a patch, it resets that key to its default rather than dropping it
* outright, so top-level removal and top-level `null` compose the same way.
*
* So `array( 'default_view' )` resets the whole `default_view` key to its
* default, `array( 'default_view' => array( 'sort' ) )` drops just its `sort`
* property, and `array( 'default_view' => array( 'fields' => array( 'f2' ) ) )`
* drops the `f2` member from its `fields` list. A name that is not present is
* ignored, and a list is renumbered after a member is removed.
*
* A spec that declares an unsupported schema version is rejected and does not
* change anything.
*
* @since 7.1.0
*
* @param array $spec The names to remove, keyed to match the configuration shape.
* @param int $version The schema version the spec was authored against.
* @return WP_View_Config_Data The instance, for chaining.
*/
public function remove( array $spec, int $version ) {
if ( $version <= 0 || $version > self::LATEST_VERSION ) {
_doing_it_wrong(
__METHOD__,
esc_html__( 'A view configuration patch must declare a supported schema version.' ),
'7.1.0'
);
return $this;
}
// A flat list names top-level keys to reset; a map recurses into each
// named key to prune from within its value.
$spec_is_list = array_is_list( $spec );
foreach ( $spec as $spec_key => $spec_value ) {
$key = $spec_is_list ? $spec_value : $spec_key;
if ( ! in_array( $key, self::CONFIG_KEYS, true ) ) {
_doing_it_wrong(
__METHOD__,
sprintf(
/* translators: %s: the configuration key. */
esc_html__( '"%s" is not a documented view configuration key.' ),
esc_html( $key )
),
'7.1.0'
);
continue;
}
if ( $spec_is_list ) {
// Removing a top-level key resets it to its default, just as a
// null patch value does.
$this->config[ $key ] = $this->defaults[ $key ] ?? array();
} elseif ( array_key_exists( $key, $this->config ) ) {
$this->config[ $key ] = $this->remove_properties( $this->config[ $key ], $spec_value );
}
}
return $this;
}
/**
* Replaces list values while merging the rest of a partial configuration.
*
* Takes the same arguments as merge() and applies the patch the same way,
* with one difference: a list in the patch replaces the current list
* wholesale instead of merging into it by member identity. Associative
* arrays still merge key by key, `null` still drops what it names, and a
* scalar still replaces the current value.
*
* It shouldn't be the default choice — a callback that replaces a list
* stops inheriting core's future additions to it — but it's useful when a
* contributor needs to pin a list to an exact set of members.
*
* The shape rule applies here too: a patch value whose shape does not match
* the current value — an associative array where a list lives, or a
* non-empty list where an associative value lives — is rejected with a
* notice and leaves the current value unchanged. An empty array is exempt,
* so replacing a list with an empty list still clears it.
*
* A patch that declares an unsupported schema version is rejected and does
* not change anything.
*
* @since 7.1.0
*
* @param array $patch The partial configuration to apply.
* @param int $version The schema version the patch was authored against.
* @return WP_View_Config_Data The instance, for chaining.
*/
public function replace( array $patch, int $version ) {
return $this->apply( $patch, $version, __METHOD__, 'replace' );
}
/**
* Merges a partial configuration into the existing one.
*
* Applies a patch of top-level keys and touches only the keys the patch
* names: a key the patch omits keeps whatever it had, and a `null` value
* drops the key it names (which resets it to its default). Each named key's
* value is then merged into the current one by value shape:
*
* - a scalar replaces the current value;
* - an associative array merges key by key, with a nested `null` deleting
* just the leaf it names;
* - a list merges into the current list by member identity.
*
* Identity is the member's value cast to a string: a bare scalar is its own
* identity, and a map is identified by the value of the first of the
* well-known identity keys (`id`, `slug`, `field`) it carries. A member
* whose identity matches one already present merges into it in place, keeping
* its position; a member with no identity is appended to the end of the list.
*
* For example, given this patch:
*
* ```php
* array(
* 'default_view' => array( 'titleField' => 'newTitleField', 'fields' => array( 'newField' ) ),
* 'default_layouts' => array( 'grid' => array( 'layout' => array( 'badgeFields' => array( 'newField' ) ) ) ),
* 'view_list' => array( array( 'slug' => 'table', 'title' => 'New title' ) ),
* )
* ```
*
* - default_view will be updated so the titleField is 'newTitleField' and the newField is appended to the list of fields.
* - default_layouts will be updated so that newField is appended to the badgeFields.
* - view_list will be updated so that the view with slug 'table' has its title changed to 'New title'.
*
* A patch value only merges into a current value of the same shape: an
* associative array where a list lives, or a non-empty list where an
* associative value lives, is rejected with a notice and leaves the current
* value unchanged. An empty array merges nothing and is a no-op — clear a
* list with replace() and an empty list, or reset a key to its default with
* a top-level `null`.
*
* A patch that declares an unsupported schema version is rejected and does
* not change anything.
*
* @since 7.1.0
*
* @param array $patch The partial configuration to merge.
* @param int $version The schema version the patch was authored against.
* @return WP_View_Config_Data The instance, for chaining.
*/
public function merge( array $patch, int $version ) {
return $this->apply( $patch, $version, __METHOD__, 'merge' );
}
/**
* Applies a patch to the configuration, top-level key by top-level key.
*
* Shared by merge(), replace(), and set(); the three differ only in how the
* value of a named key is applied, which is carried by $mode:
*
* - `merge` merges the value into the current one, lists by member identity;
* - `replace` merges the value in the same way but swaps lists wholesale;
* - `set` swaps the whole value in wholesale, without merging.
*
* In every mode a top-level `null` resets the key it names to its default, a
* nested `null` drops the property it names, and an omitted key is left
* untouched, so all three treat nulls the same way at every depth.
*
* @since 7.1.0
*
* @param array $patch The partial configuration to apply.
* @param int $version The schema version the patch was authored against.
* @param string $method The public method the patch was passed to, for misuse reporting.
* @param string $mode How to apply each named key's value: `merge`, `replace`, or `set`.
* @return WP_View_Config_Data The instance, for chaining.
*/
private function apply( array $patch, int $version, $method, $mode ) {
if ( $version <= 0 || $version > self::LATEST_VERSION ) {
_doing_it_wrong(
esc_html( $method ),
esc_html__( 'A view configuration patch must declare a supported schema version.' ),
'7.1.0'
);
return $this;
}
foreach ( $patch as $key => $value ) {
if ( ! in_array( $key, self::CONFIG_KEYS, true ) ) {
_doing_it_wrong(
esc_html( $method ),
sprintf(
/* translators: %s: the configuration key. */
esc_html__( '"%s" is not a documented view configuration key.' ),
esc_html( $key )
),
'7.1.0'
);
continue;
}
// A null patch value makes the top-level property reset to defaults.
if ( null === $value ) {
$this->config[ $key ] = $this->defaults[ $key ] ?? array();
continue;
}
// set() swaps the whole value in; merge()/replace() merge it into the
// current one, differing only in how they treat lists. In every mode a
// nested null still drops the property it names.
$this->config[ $key ] = 'set' === $mode
? $this->strip_nulls( $value )
: $this->merge_properties( $this->config[ $key ] ?? array(), $value, 'replace' === $mode );
}
return $this;
}
/**
* Recursively drops every property whose value is `null` from a value.
*
* set() swaps a named key's value in wholesale rather than merging it into
* the current one, so it has no existing leaf for a nested `null` to delete
* the way merge() and replace() do. Stripping nulls here gives a nested
* `null` the same "drop the property it names" meaning under set() that it
* carries everywhere else. The same applies to a list replace() swaps in
* wholesale. A list is renumbered after a member is removed so removed
* entries do not leave gaps.
*
* @since 7.1.0
*
* @param mixed $value The value to strip nulls from.
* @return mixed The value with every `null` property removed, recursively.
*/
private function strip_nulls( $value ) {
if ( ! is_array( $value ) ) {
return $value;
}
$result = array();
foreach ( $value as $key => $item ) {
// A null value drops the property it names.
if ( null === $item ) {
continue;
}
$result[ $key ] = $this->strip_nulls( $item );
}
// Renumber a list so a removed member does not leave a gap.
return array_is_list( $value ) ? array_values( $result ) : $result;
}
/**
* Merges an incoming value into the current one, recursing by value shape.
*
* This is the core of the merge algorithm and is applied at every nesting
* level: a scalar (or `null`) in $incoming replaces $current outright, an
* associative array merges key by key (recursing here for each key, with a
* `null` value deleting that key), and a list either replaces $current
* wholesale ($replace_lists) or merges into it by member identity. The
* $replace_lists flag is carried down through associative nesting so that,
* under replace(), every list reached along the way is swapped wholesale.
*
* An array in $incoming only merges into a current value of the same shape.
* A non-empty mismatch — an associative array where a list lives, or a
* non-empty list where an associative value lives — is reported with
* _doing_it_wrong() and leaves the current value unchanged, so a malformed
* patch cannot silently destroy configuration. An empty array is
* shape-ambiguous and merges nothing, so it is a no-op: clearing a list is
* spelled replace() with an empty list, and resetting a key is spelled
* `null`.
*
* @since 7.1.0
*
* @param mixed $current The current value.
* @param mixed $incoming The incoming value.
* @param bool $replace_lists Whether a list in $incoming replaces the current list
* wholesale instead of merging into it by member identity.
* @return mixed The merged value.
*/
private function merge_properties( $current, $incoming, $replace_lists ) {
// Scalar properties are merged as-is.
if ( ! is_array( $incoming ) ) {
return $incoming;
}
// Numerical indexed arrays are expected to be lists (sequential integer keys starting at 0).
if ( array_is_list( $incoming ) ) {
// A non-empty list only lands where a list (or nothing) lives, under
// merge() and replace() alike. An empty array is shape-ambiguous and
// exempt, so replace() with an empty list can still clear a list.
if ( array() !== $incoming && is_array( $current ) && ! array_is_list( $current ) && array() !== $current ) {
_doing_it_wrong(
__METHOD__,
esc_html__( 'A view configuration patch value must match the shape of the value it patches: a list merges into a list, and an associative array into an associative array.' ),
'7.1.0'
);
return $current;
}
// replace() takes an incoming list as-is; merge() merges it by member identity.
if ( $replace_lists ) {
// As-is except for nulls: a list swapped in wholesale has no
// existing leaf for a null to delete (the same rationale as
// set()), so a null member is dropped rather than stored.
return $this->strip_nulls( $incoming );
}
// An empty list has no members to merge, and an empty array is
// shape-ambiguous, so merging one is a no-op rather than a reset.
if ( array() === $incoming ) {
return $current;
}
return $this->merge_list_by_identity(
is_array( $current ) && array_is_list( $current ) ? $current : array(),
$incoming
);
}
// Consider any other array as associative (keys are strings).
if ( is_array( $current ) && array_is_list( $current ) && array() !== $current ) {
_doing_it_wrong(
__METHOD__,
esc_html__( 'A view configuration patch value must match the shape of the value it patches: a list merges into a list, and an associative array into an associative array.' ),
'7.1.0'
);
return $current;
}
$result = is_array( $current ) && ! array_is_list( $current ) ? $current : array();
foreach ( $incoming as $key => $value ) {
// A null patch value deletes the property.
if ( null === $value ) {
unset( $result[ $key ] );
continue;
}
$result[ $key ] = $this->merge_properties(
array_key_exists( $key, $result ) ? $result[ $key ] : array(),
$value,
$replace_lists
);
}
return $result;
}
/**
* Removes the properties a spec names from the current value.
*
* The mirror of merge_properties(), applied at every nesting level: a list in
* $spec names entries to delete from $current — associative keys are unset,
* and list members are matched by identity (list_item_identity) and dropped —
* while an associative $spec recurses into each named entry to prune from
* within it. A name absent from $current is ignored, and a list is renumbered
* after members are removed so it keeps sequential keys.
*
* @since 7.1.0
*
* @param mixed $current The current value.
* @param mixed $spec The names to remove from it.
* @return mixed The pruned value.
*/
private function remove_properties( $current, $spec ) {
if ( ! is_array( $current ) || ! is_array( $spec ) ) {
return $current;
}
$current_is_list = array_is_list( $current );
if ( array_is_list( $spec ) ) {
// Each entry names something to delete from the current value.
foreach ( $spec as $name ) {
if ( $current_is_list ) {
$current = $this->remove_list_member( $current, $name );
} else {
unset( $current[ $name ] );
}
}
} else {
// Each key names an entry to recurse into and prune from within.
foreach ( $spec as $name => $subspec ) {
if ( $current_is_list ) {
foreach ( $current as $index => $member ) {
if ( $this->list_item_identity( $member ) === (string) $name ) {
$current[ $index ] = $this->remove_properties( $member, $subspec );
break;
}
}
} elseif ( array_key_exists( $name, $current ) ) {
$current[ $name ] = $this->remove_properties( $current[ $name ], $subspec );
}
}
}
// Renumber so a list from which a member was removed keeps sequential keys.
return $current_is_list ? array_values( $current ) : $current;
}
/**
* Removes the first list member matching an identity, leaving the rest.
*
* @since 7.1.0
*
* @param array $members The current list.
* @param mixed $identity The identity of the member to remove.
* @return array The list with the matching member removed, if any.
*/
private function remove_list_member( array $members, $identity ) {
foreach ( $members as $index => $member ) {
if ( $this->list_item_identity( $member ) === (string) $identity ) {
unset( $members[ $index ] );
break;
}
}
return $members;
}
/**
* Merges an incoming list into the current one by member identity.
*
* A member of the incoming list whose identity matches one already present
* merges into it in place, keeping its position; an unmatched member is
* appended to the end, except a literal `null`, which carries no identity
* and holds nothing to merge and so is dropped. An appended member has no
* existing leaf for a nested `null` to delete (the same rationale as set()),
* so its nulls are stripped rather than stored. A matched member's contents
* merge recursively with the same rules (merge_properties), so the
* identity-aware merge applies at
* any nesting level: each key named by the patch is substituted while the
* others are left intact, and a list nested inside a member merges by
* identity just like the list it lives in.
*
* @since 7.1.0
*
* @param array $current The current list.
* @param array $incoming The incoming list.
* @return array The merged list.
*/
private function merge_list_by_identity( array $current, array $incoming ) {
$result = $current;
foreach ( $incoming as $item ) {
// A null member carries no identity and holds nothing to merge,
// so it is dropped rather than appended as a literal null.
if ( null === $item ) {
continue;
}
$identity = $this->list_item_identity( $item );
// Find the index of the existing member with the same identity, if any.
// If there's none, append the incoming member to the end of the list.
$index = null;
if ( null !== $identity ) {
foreach ( $result as $i => $existing ) {
if ( $this->list_item_identity( $existing ) === $identity ) {
$index = $i;
break;
}
}
}
if ( null === $index ) {
// An appended member has no existing leaf for a nested null to
// delete, so nulls are dropped rather than stored.
$result[] = $this->strip_nulls( $item );
continue;
}
// Otherwise, merge the incoming member into the existing one in place.
$result[ $index ] = $this->merge_properties( $result[ $index ], $item, false );
}
return $result;
}
/**
* Resolves the identity used to match a list member against another.
*
* The identity is simply the member's value cast to a string, regardless of
* which key carries it: a bare scalar is its own identity, and a map is
* identified by the value of the first of the well-known identity keys
* (`id`, `slug`, `field`) it carries. Because the key is not part of
* the identity, a bare field like `'f3'` matches any map carrying that
* value, whether it appears as `array( 'id' => 'f3' )`,
* `array( 'slug' => 'f3' )`, and so on — this lets the same shorthand target
* lists keyed by different fields. Casting to string keeps numeric
* identities matching whether they arrive as an int or a string. Anything
* else (e.g. a nested list) has no identity and never matches, so it is
* always appended.
*
* @since 7.1.0
*
* @param mixed $item The list member.
* @return string|null The identity, or null when the member has none.
*/
private function list_item_identity( $item ) {
if ( is_scalar( $item ) ) {
return (string) $item;
}
if ( is_array( $item ) && ! array_is_list( $item ) ) {
foreach ( array( 'id', 'slug', 'field' ) as $key ) {
if ( isset( $item[ $key ] ) && is_scalar( $item[ $key ] ) ) {
return (string) $item[ $key ];
}
}
}
return null;
}
}