Function scanner for Twig AST

src/RobustTwigFunctionsScanner.php

@@ -0,0 +1,71 @@
+<?php
+
+namespace WP_CLI\I18n;
+
+use Gettext\Utils\FunctionsScanner;
+
+/**
+ * This is a function scanner for Twig templates. The initial string (whether template text or filename) is parsed.
+ * Then getFunctions() recursively traverses nodes.
+ * Nodes expressing a function call to one of the WordPress i18n functions (see parent {$this->functions) and saveGettextFunctions())
+ * are extracted.
+ */
+final class RobustTwigFunctionsScanner extends PhpFunctionsScanner {
+    public function __construct( $string, $twig, $func_names ) {
+        $this->tokens = $twig->parse( $twig->tokenize( new \Twig_Source( $string, '' ) ) );
+        $this->functions = $func_names;
+    }
+
+    /**
+     * A pseudo-generator to extract twig nodes corresponding to i18n function calls.
+     * @param array $constants Unused yet.
+     * @return array List of functions arguments/line-number compatible with PhpFunctionsScanner.
+     */
+    public function getFunctions( array $constants = [] ) {
+        return self::_get_gettext_functions( $this->tokens );
+    }
+
+    private function is_gettext_function( $obj ) {
+        return ( $obj instanceof \Twig_Node_Expression_Function && in_array( $obj->getAttribute( 'name' ), $this->functions, TRUE ) );
+    }
+
+    private function _get_gettext_functions( $tokens ) {
+        if ( is_array( $tokens ) ) {
+            $functions = [];
+            foreach($tokens as $v) {
+                $functions = array_merge( $functions, self::_get_gettext_functions( $v ) );
+            }
+            return $functions;
+        }
+
+        $value = $tokens;
+        if ( $this->is_gettext_function( $value )) {
+            $arguments_obj = (array)$value->getNode( 'arguments' )->getIterator();
+            $name = $value->getAttribute('name');
+            $line = $value->getTemplateLine();
+
+            // basic verification of node arguments
+            if ( ! ( $arguments_obj[0] instanceof \Twig_Node_Expression_Constant && $arguments_obj[1] instanceof \Twig_Node_Expression_Constant ) ) {
+                \WP_CLI::warning( "Translation expression does not contains constant expressions " . PHP_EOL );
+                printf( STDERR, print_r( $arguments_obj, TRUE ) );
+                return [];
+            }
+
+            $arguments = array_map( function( $obj ) use( $name ) {
+                if ($name == '_n' && $obj instanceof \Twig_Node_Expression_GetAttr) {
+                    return "count";
+                } else {
+                    return $obj->getAttribute('value');
+                }
+            }, $arguments_obj );
+
+            return [ [ $name, $line, $arguments ] ];
+        }
+
+        $functions = [];
+        foreach( $tokens->getIterator() as $v) {
+            $functions = array_merge( $functions, self::_get_gettext_functions( $v ) );
+        }
+        return $functions;
+    }
+}