Add RecursiveDataStructureTraverser helper to manipulate nested data

Author: petitphp

src/Cache/NonExistentKeyException.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace WP_CLI\Cache;
+
+use OutOfBoundsException;
+
+class NonExistentKeyException extends OutOfBoundsException {
+	/** @var RecursiveDataStructureTraverser */
+	protected $traverser;
+
+	/**
+	 * @param RecursiveDataStructureTraverser $traverser
+	 */
+	public function set_traverser( $traverser ) {
+		$this->traverser = $traverser;
+	}
+
+	/**
+	 * @return RecursiveDataStructureTraverser
+	 */
+	public function get_traverser() {
+		return $this->traverser;
+	}
+}

src/Cache/RecursiveDataStructureTraverser.php

@@ -0,0 +1,182 @@
+<?php
+
+namespace WP_CLI\Cache;
+
+use UnexpectedValueException;
+
+class RecursiveDataStructureTraverser {
+
+	/**
+	 * @var mixed The data to traverse set by reference.
+	 */
+	protected $data;
+
+	/**
+	 * @var null|string The key the data belongs to in the parent's data.
+	 */
+	protected $key;
+
+	/**
+	 * @var null|static The parent instance of the traverser.
+	 */
+	protected $parent;
+
+	/**
+	 * RecursiveDataStructureTraverser constructor.
+	 *
+	 * @param mixed $data The data to read/manipulate by reference.
+	 * @param string|int $key The key/property the data belongs to.
+	 * @param static $parent
+	 */
+	public function __construct( &$data, $key = null, $parent = null ) {
+		$this->data   =& $data;
+		$this->key    = $key;
+		$this->parent = $parent;
+	}
+
+	/**
+	 * Get the nested value at the given key path.
+	 *
+	 * @param string|int|array $key_path
+	 *
+	 * @return static
+	 */
+	public function get( $key_path ) {
+		return $this->traverse_to( (array) $key_path )->value();
+	}
+
+	/**
+	 * Get the current data.
+	 *
+	 * @return mixed
+	 */
+	public function value() {
+		return $this->data;
+	}
+
+	/**
+	 * Update a nested value at the given key path.
+	 *
+	 * @param string|int|array $key_path
+	 * @param mixed $value
+	 */
+	public function update( $key_path, $value ) {
+		$this->traverse_to( (array) $key_path )->set_value( $value );
+	}
+
+	/**
+	 * Update the current data with the given value.
+	 *
+	 * This will mutate the variable which was passed into the constructor
+	 * as the data is set and traversed by reference.
+	 *
+	 * @param mixed $value
+	 */
+	public function set_value( $value ) {
+		$this->data = $value;
+	}
+
+	/**
+	 * Unset the value at the given key path.
+	 *
+	 * @param $key_path
+	 */
+	public function delete( $key_path ) {
+		$this->traverse_to( (array) $key_path )->unset_on_parent();
+	}
+
+	/**
+	 * Define a nested value while creating keys if they do not exist.
+	 *
+	 * @param array $key_path
+	 * @param mixed $value
+	 */
+	public function insert( $key_path, $value ) {
+		try {
+			$this->update( $key_path, $value );
+		} catch ( NonExistentKeyException $exception ) {
+			$exception->get_traverser()->create_key();
+			$this->insert( $key_path, $value );
+		}
+	}
+
+	/**
+	 * Delete the key on the parent's data that references this data.
+	 */
+	public function unset_on_parent() {
+		$this->parent->delete_by_key( $this->key );
+	}
+
+	/**
+	 * Delete the given key from the data.
+	 *
+	 * @param $key
+	 */
+	public function delete_by_key( $key ) {
+		if ( is_array( $this->data ) ) {
+			unset( $this->data[ $key ] );
+		} else {
+			unset( $this->data->$key );
+		}
+	}
+
+	/**
+	 * Get an instance of the traverser for the given hierarchical key.
+	 *
+	 * @param array $key_path Hierarchical key path within the current data to traverse to.
+	 *
+	 * @throws NonExistentKeyException
+	 *
+	 * @return static
+	 */
+	public function traverse_to( array $key_path ) {
+		$current = array_shift( $key_path );
+
+		if ( null === $current ) {
+			return $this;
+		}
+
+		if ( ! $this->exists( $current ) ) {
+			$exception = new NonExistentKeyException( "No data exists for key \"{$current}\"" );
+			$exception->set_traverser( new static( $this->data, $current, $this->parent ) );
+			throw $exception;
+		}
+
+		foreach ( $this->data as $key => &$key_data ) {
+			if ( $key === $current ) {
+				$traverser = new static( $key_data, $key, $this );
+				return $traverser->traverse_to( $key_path );
+			}
+		}
+	}
+
+	/**
+	 * Create the key on the current data.
+	 *
+	 * @throws UnexpectedValueException
+	 */
+	protected function create_key() {
+		if ( is_array( $this->data ) ) {
+			$this->data[ $this->key ] = null;
+		} elseif ( is_object( $this->data ) ) {
+			$this->data->{$this->key} = null;
+		} else {
+			$type = gettype( $this->data );
+			throw new UnexpectedValueException(
+				"Cannot create key \"{$this->key}\" on data type {$type}"
+			);
+		}
+	}
+
+	/**
+	 * Check if the given key exists on the current data.
+	 *
+	 * @param string $key
+	 *
+	 * @return bool
+	 */
+	public function exists( $key ) {
+		return ( is_array( $this->data ) && array_key_exists( $key, $this->data ) ) ||
+			( is_object( $this->data ) && property_exists( $this->data, $key ) );
+	}
+}

src/Cache/Utils.php

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+<?php
+
+namespace WP_CLI\Cache;
+
+class Utils {
+
+	/**
+	 * Check whether any input is passed to STDIN.
+	 *
+	 * @return bool
+	 */
+	public static function has_stdin() {
+		$handle  = fopen( 'php://stdin', 'r' );
+		$read    = array( $handle );
+		$write   = null;
+		$except  = null;
+		$streams = stream_select( $read, $write, $except, 0 );
+		fclose( $handle );
+
+		return 1 === $streams;
+	}
+}