Add Js\ByRef() class to allow values to be passed by reference to JS.

Author: cscott

lib/startup.php

@@ -3,4 +3,15 @@
 // helpers which are easier to write in PHP than in C.
 namespace Js;
 
+// Simple marker class to indicate that a given value should be
+// passed by reference.  Internally we'll call `getValue` to
+// unwrap the reference inside.
+class ByRef {
+    public $value;
+    public function __construct(&$value) { $this->value =& $value; }
+    public function &getValue() {
+        return $this->value;
+    }
+}
+
 ?>

src/node_php_jsobject_class.cc

@@ -359,10 +359,14 @@ class JsInvokeMsg : public MessageToJs {
               objid_t objId, zval *member, ulong argc, zval **argv TSRMLS_DC)
       : MessageToJs(m, callback, isSync),
         object_(), member_(m, member TSRMLS_CC),
-        argc_(argc), argv_(Value::NewArray(m, argc, argv TSRMLS_CC)) {
+        argc_(argc), argv_() {
     object_.SetJsObject(objId);
+    argv_.SetArrayByValue(argc, [m, argv TSRMLS_CC](uint32_t idx, Value& v) {
+      ZVal z(argv[idx] ZEND_FILE_LINE_CC);
+      z.UnwrapByRef(TSRMLS_C);  // Unwrap Js\ByRef values.
+      v.Set(m, z TSRMLS_CC);
+    });
   }
-  ~JsInvokeMsg() override { delete[] argv_; }
 
  protected:
   void InJs(JsObjectMapper *m) override {
@@ -431,7 +435,7 @@ class JsInvokeMsg : public MessageToJs {
   Value object_;
   Value member_;
   ulong argc_;
-  Value *argv_;
+  Value argv_;
 };
 
 // XXX Figure out how to actually invoke methods async.
@@ -442,8 +446,6 @@ ZEND_BEGIN_ARG_INFO_EX(node_php_jsobject_call_args, 0, 1/*return by ref*/, 1)
     ZEND_ARG_ARRAY_INFO(0, args, 0)
 ZEND_END_ARG_INFO()
 
-// XXX can't figure out how to pass arrays by reference instead of
-// by value.
 PHP_METHOD(JsObject, __call) {
   zval *member; zval *args;
   TRACE(">");

src/values.h

@@ -18,6 +18,7 @@
 
 extern "C" {
 #include "main/php.h"
+#include "Zend/zend_interfaces.h"  // for zend_call_method_with_*
 }
 
 #include "src/macros.h"
@@ -101,6 +102,24 @@ class ZVal {
     return z;
   }
 
+  // Unwrap references protected by Js\ByRef
+  inline void UnwrapByRef(TSRMLS_D) {
+    if (!IsObject()) { return; }
+    assert(zvalp && !transferred_);
+    zend_class_entry *ce = Z_OBJCE_P(zvalp);
+    // XXX cache the zend_class_entry at startup so we can do a simple
+    // pointer comparison instead of looking at the class name
+    if (ce->name_length == 8 && strcmp("Js\\ByRef", ce->name) == 0) {
+      // Unwrap!
+      zval *rv;
+      zend_call_method_with_0_params(&zvalp, nullptr, nullptr, "getValue", &rv);
+      if (rv) {
+        zval_ptr_dtor(&zvalp);
+        zvalp = rv;
+      }
+    }
+  }
+
   // Support a PHP calling convention where the actual zval object
   // is owned by the caller, but the contents are transferred to the
   // callee.
@@ -694,6 +713,10 @@ class Value {
   inline bool IsArrayByValue() const {
     return (type_ == VALUE_ARRAY_BY_VALUE);
   }
+  inline Value& operator[](int i) const {
+    assert(IsArrayByValue());
+    return array_by_value_.item_[i];
+  }
   bool AsBool() const {
     switch (type_) {
     case VALUE_BOOL:

test/byref.js

@@ -0,0 +1,48 @@
+// Test cases for passing values "by reference".
+var StringStream = require('../test-stream.js');
+
+var path = require('path');
+var should = require('should');
+
+describe('Wrapped PHP objects passed by reference to JavaScript', function() {
+  var php = require('../');
+  var defaultCode = [
+    'call_user_func(function () {',
+    '  $ctxt = $_SERVER["CONTEXT"];',
+    '  #include $ctxt->file;',
+    '',
+    '  $a = {{VALUE}};',
+    '  $b = $a;',
+    '  $ctxt->jsfunc(new Js\\ByRef($a));',
+    '  var_dump($a);',
+    '  var_dump($b);',
+    '})',
+  ].join('\n');
+  var test = function(value, f) {
+    var code = defaultCode.replace('{{VALUE}}', value);
+    var out = new StringStream();
+    return php.request({ source: code, context: {
+      jsfunc: f,
+      file: path.join(__dirname, 'byref.php'),
+    }, stream: out, }).then(function(v) { return [v, out.toString()]; });
+  };
+  it('arrays', function() {
+    return test('array("a"=>"b")',function(a, b) {
+      a[1] = 2;
+    }).spread(function(v, out) {
+      out.should.equal([
+        'array(2) {',
+        '  ["a"]=>',
+        '  string(1) "b"',
+        '  [1]=>',
+        '  int(2)',
+        '}',
+        'array(1) {',
+        '  ["a"]=>',
+        '  string(1) "b"',
+        '}',
+        '',
+      ].join('\n'));
+    });
+  });
+});

test/phparray.js

@@ -535,38 +535,14 @@ describe('Wrapped PHP arrays accessed from JavaScript', function() {
   });
   it('can be passed by reference', function() {
     return test(function(arr) {
-      arr.offsetSet(1, 2);
-      arr.offsetSet('foo', 'bar');
-      // XXX make the below work.
-      // `arr[1] = 2;`
-      // `arr['foo'] = 'bar';`
+      arr[1] = 2;
+      arr.set('foo', 'bar');
     }, [
       'call_user_func(function() {',
-      // XXX this `wrap` class should be built-in as Js\ArrayByRef
-      '  class wrap implements ArrayAccess, Countable {',
-      '    private $a;',
-      '    public function __construct(&$a) { $this->a =& $a; }',
-      '    public function offsetSet($offset, $value) {',
-      '      if (is_null($offset)) { $this->a[] = $value; }',
-      '      else { $this->a[$offset] = $value; }',
-      '    }',
-      '    public function offsetExists($offset) {',
-      '      return isset($this->a[$offset]);',
-      '    }',
-      '    public function offsetUnset($offset) {',
-      '      unset($this->a[$offset]);',
-      '    }',
-      '    public function offsetGet($offset) {',
-      '      return isset($this->a[$offset]) ? $this->a[$offset] : null;',
-      '    }',
-      '    public function count() {',
-      '      return count($this->a);',
-      '    }',
-      '  }',
       '  $a = array("a" => "b");',
       '  $b = $a;',
       '  $ctxt = $_SERVER["CONTEXT"];',
-      '  $ctxt->jsfunc(new wrap($a));',
+      '  $ctxt->jsfunc(new Js\\ByRef($a));',
       '  var_dump($a);',
       '  var_dump($b);',
       '})',