Chris@13: <?php
Chris@13: 
Chris@13: /*
Chris@13:  * This file is part of Psy Shell.
Chris@13:  *
Chris@13:  * (c) 2012-2018 Justin Hileman
Chris@13:  *
Chris@13:  * For the full copyright and license information, please view the LICENSE
Chris@13:  * file that was distributed with this source code.
Chris@13:  */
Chris@13: 
Chris@13: namespace Psy\CodeCleaner;
Chris@13: 
Chris@13: use PhpParser\Node;
Chris@13: use PhpParser\Node\Name;
Chris@13: use PhpParser\Node\Name\FullyQualified as FullyQualifiedName;
Chris@13: use PhpParser\Node\Stmt\GroupUse;
Chris@13: use PhpParser\Node\Stmt\Namespace_;
Chris@13: use PhpParser\Node\Stmt\Use_;
Chris@13: use PhpParser\NodeTraverser;
Chris@13: 
Chris@13: /**
Chris@13:  * Provide implicit use statements for subsequent execution.
Chris@13:  *
Chris@13:  * The use statement pass remembers the last use statement line encountered:
Chris@13:  *
Chris@13:  *     use Foo\Bar as Baz;
Chris@13:  *
Chris@13:  * ... which it then applies implicitly to all future evaluated code, until the
Chris@13:  * current namespace is replaced by another namespace.
Chris@13:  */
Chris@13: class UseStatementPass extends CodeCleanerPass
Chris@13: {
Chris@13:     private $aliases       = [];
Chris@13:     private $lastAliases   = [];
Chris@13:     private $lastNamespace = null;
Chris@13: 
Chris@13:     /**
Chris@13:      * Re-load the last set of use statements on re-entering a namespace.
Chris@13:      *
Chris@13:      * This isn't how namespaces normally work, but because PsySH has to spin
Chris@13:      * up a new namespace for every line of code, we do this to make things
Chris@13:      * work like you'd expect.
Chris@13:      *
Chris@13:      * @param Node $node
Chris@13:      */
Chris@13:     public function enterNode(Node $node)
Chris@13:     {
Chris@13:         if ($node instanceof Namespace_) {
Chris@13:             // If this is the same namespace as last namespace, let's do ourselves
Chris@13:             // a favor and reload all the aliases...
Chris@17:             if (\strtolower($node->name) === \strtolower($this->lastNamespace)) {
Chris@13:                 $this->aliases = $this->lastAliases;
Chris@13:             }
Chris@13:         }
Chris@13:     }
Chris@13: 
Chris@13:     /**
Chris@13:      * If this statement is a namespace, forget all the aliases we had.
Chris@13:      *
Chris@13:      * If it's a use statement, remember the alias for later. Otherwise, apply
Chris@13:      * remembered aliases to the code.
Chris@13:      *
Chris@13:      * @param Node $node
Chris@13:      */
Chris@13:     public function leaveNode(Node $node)
Chris@13:     {
Chris@13:         if ($node instanceof Use_) {
Chris@13:             // Store a reference to every "use" statement, because we'll need
Chris@13:             // them in a bit.
Chris@13:             foreach ($node->uses as $use) {
Chris@17:                 $alias = $use->alias ?: \end($use->name->parts);
Chris@17:                 $this->aliases[\strtolower($alias)] = $use->name;
Chris@13:             }
Chris@13: 
Chris@13:             return NodeTraverser::REMOVE_NODE;
Chris@13:         } elseif ($node instanceof GroupUse) {
Chris@13:             // Expand every "use" statement in the group into a full, standalone
Chris@13:             // "use" and store 'em with the others.
Chris@13:             foreach ($node->uses as $use) {
Chris@17:                 $alias = $use->alias ?: \end($use->name->parts);
Chris@17:                 $this->aliases[\strtolower($alias)] = Name::concat($node->prefix, $use->name, [
Chris@13:                     'startLine' => $node->prefix->getAttribute('startLine'),
Chris@13:                     'endLine'   => $use->name->getAttribute('endLine'),
Chris@13:                 ]);
Chris@13:             }
Chris@13: 
Chris@13:             return NodeTraverser::REMOVE_NODE;
Chris@13:         } elseif ($node instanceof Namespace_) {
Chris@13:             // Start fresh, since we're done with this namespace.
Chris@13:             $this->lastNamespace = $node->name;
Chris@13:             $this->lastAliases   = $this->aliases;
Chris@13:             $this->aliases       = [];
Chris@13:         } else {
Chris@13:             foreach ($node as $name => $subNode) {
Chris@13:                 if ($subNode instanceof Name) {
Chris@13:                     // Implicitly thunk all aliases.
Chris@13:                     if ($replacement = $this->findAlias($subNode)) {
Chris@13:                         $node->$name = $replacement;
Chris@13:                     }
Chris@13:                 }
Chris@13:             }
Chris@13: 
Chris@13:             return $node;
Chris@13:         }
Chris@13:     }
Chris@13: 
Chris@13:     /**
Chris@13:      * Find class/namespace aliases.
Chris@13:      *
Chris@13:      * @param Name $name
Chris@13:      *
Chris@13:      * @return FullyQualifiedName|null
Chris@13:      */
Chris@13:     private function findAlias(Name $name)
Chris@13:     {
Chris@17:         $that = \strtolower($name);
Chris@13:         foreach ($this->aliases as $alias => $prefix) {
Chris@13:             if ($that === $alias) {
Chris@13:                 return new FullyQualifiedName($prefix->toString());
Chris@17:             } elseif (\substr($that, 0, \strlen($alias) + 1) === $alias . '\\') {
Chris@17:                 return new FullyQualifiedName($prefix->toString() . \substr($name, \strlen($alias)));
Chris@13:             }
Chris@13:         }
Chris@13:     }
Chris@13: }