Merge pull request #61 from iodide-project/more-proxy

Add a lot more jsproxy functionality

docs/type_conversions.md

@@ -42,23 +42,55 @@ Any of the types not listed above are shared between languages using proxies
 that allow methods and some operators to be called on the object from the other
 language.
 
+### Javascript from Python
 
 When passing a Javascript object to Python, an extension type is used to
 delegate Python operations to the Javascript side. The following operations are
 currently supported. (More should be possible in the future -- work in ongoing
 to make this more complete):
 
-| Python         | Javascript     |
-|----------------|----------------|
-| `repr(x)`      | `x.toString()` |
-| `x.foo`        | `x.foo`        |
-| `x.foo = bar`  | `x.foo = bar`  |
-| `x(...)`       | `x(...)`       |
-| `x.foo(...)`   | `x.foo(...)`   |
-| `X.new(...)`   | `new X(...)`   |
-| `len(x)`       | `x.length`     |
-| `x[foo]`       | `x[foo]`       |
-| `x[foo] = bar` | `x[foo] = bar` |
+| Python         | Javascript      |
+|----------------|-----------------|
+| `repr(x)`      | `x.toString()`  |
+| `x.foo`        | `x.foo`         |
+| `x.foo = bar`  | `x.foo = bar`   |
+| `del x.foo`    | `delete x.foo`  |
+| `x(...)`       | `x(...)`        |
+| `x.foo(...)`   | `x.foo(...)`    |
+| `X.new(...)`   | `new X(...)`    |
+| `len(x)`       | `x.length`      |
+| `x[foo]`       | `x[foo]`        |
+| `x[foo] = bar` | `x[foo] = bar`  |
+| `del x[foo]`   | `delete x[foo]` |
+| `x == y`       | `x == y`        |
+| `x.typeof`     | `typeof x`      |
+
+One important difference between Python objects and Javascript objects is that
+if you access a missing member in Python, an exception is raised. In Javascript,
+it returns `undefined`. Since we can't make any assumptions about whether the
+Javascript member is missing or simply set to `undefined`, Python mirrors the
+Javascript behavior. For example:
+
+```javascript
+// Javascript
+class Point {
+  constructor(x, y) {
+    this.x = x;
+    this.y = y;
+  }
+}
+point = new Point(42, 43))
+```
+
+```python
+# python
+from js import point
+assert point.y == 43
+del point.y
+assert point.y is None
+```
+
+### Python from Javascript
 
 When passing a Python object to Javascript, the Javascript [Proxy
 API](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy)

src/hiwire.c

@@ -100,6 +100,12 @@ EM_JS(void, hiwire_set_member_string, (int idobj, int ptrkey, int idval), {
   jsobj[jskey] = jsval;
 });
 
+EM_JS(void, hiwire_delete_member_string, (int idobj, int ptrkey), {
+  var jsobj = Module.hiwire_get_value(idobj);
+  var jskey = UTF8ToString(ptrkey);
+  delete jsobj[jskey];
+});
+
 EM_JS(int, hiwire_get_member_int, (int idobj, int idx), {
   var jsobj = Module.hiwire_get_value(idobj);
   return Module.hiwire_new_value(jsobj[idx]);
@@ -109,6 +115,25 @@ EM_JS(void, hiwire_set_member_int, (int idobj, int idx, int idval), {
   Module.hiwire_get_value(idobj)[idx] = Module.hiwire_get_value(idval);
 });
 
+EM_JS(int, hiwire_get_member_obj, (int idobj, int ididx), {
+  var jsobj = Module.hiwire_get_value(idobj);
+  var jsidx = Module.hiwire_get_value(ididx);
+  return Module.hiwire_new_value(jsobj[jsidx]);
+});
+
+EM_JS(void, hiwire_set_member_obj, (int idobj, int ididx, int idval), {
+  var jsobj = Module.hiwire_get_value(idobj);
+  var jsidx = Module.hiwire_get_value(ididx);
+  var jsval = Module.hiwire_get_value(idval);
+  jsobj[jsidx] = jsval;
+});
+
+EM_JS(void, hiwire_delete_member_obj, (int idobj, int ididx), {
+    var jsobj = Module.hiwire_get_value(idobj);
+    var jsidx = Module.hiwire_get_value(ididx);
+    delete jsobj[jsidx];
+});
+
 EM_JS(void, hiwire_call, (int idfunc, int idargs), {
   var jsfunc = Module.hiwire_get_value(idfunc);
   var jsargs = Module.hiwire_get_value(idargs);
@@ -146,3 +171,33 @@ EM_JS(int, hiwire_is_function, (int idobj), {
 EM_JS(int, hiwire_to_string, (int idobj), {
   return Module.hiwire_new_value(Module.hiwire_get_value(idobj).toString());
 });
+
+EM_JS(int, hiwire_typeof, (int idobj), {
+  return Module.hiwire_new_value(typeof Module.hiwire_get_value(idobj));
+});
+
+#define MAKE_OPERATOR(name, op) \
+  EM_JS(int, hiwire_##name, (int ida, int idb), { \
+    return (Module.hiwire_get_value(ida) op Module.hiwire_get_value(idb)) ? 1 : 0; \
+  });
+
+MAKE_OPERATOR(less_than, <);
+MAKE_OPERATOR(less_than_equal, <=);
+MAKE_OPERATOR(equal, ==);
+MAKE_OPERATOR(not_equal, !=);
+MAKE_OPERATOR(greater_than, >);
+MAKE_OPERATOR(greater_than_equal, >=);
+
+EM_JS(int, hiwire_next, (int idobj), {
+  var jsobj = Module.hiwire_get_value(idobj);
+  if (jsobj.next === undefined) {
+    return -1;
+  }
+
+  return Module.hiwire_new_value(jsobj.next());
+});
+
+EM_JS(int, hiwire_nonzero, (int idobj), {
+  var jsobj = Module.hiwire_get_value(idobj);
+  return (jsobj != 0) ? 1 : 0;
+});

src/hiwire.h

@@ -179,6 +179,14 @@ hiwire_get_member_string(int idobj, int ptrname);
 void
 hiwire_set_member_string(int idobj, int ptrname, int idval);
 
+/**
+ * Delete an object member by string.
+ *
+ * The string is a char* to null-terminated UTF8.
+ */
+void
+hiwire_delete_member_string(int idobj, int ptrname);
+
 /**
  * Get an object member by integer.
  *
@@ -194,11 +202,32 @@ hiwire_get_member_int(int idobj, int idx);
  *
  * The integer is a C integer, not an id reference to a Javascript integer.
  *
- * Returns: New reference
  */
 void
 hiwire_set_member_int(int idobj, int idx, int idval);
 
+/**
+ * Get an object member by object.
+ *
+ * Returns: New reference
+ */
+int
+hiwire_get_member_obj(int idobj, int ididx);
+
+/**
+ * Set an object member by object.
+ *
+ */
+void
+hiwire_set_member_obj(int idobj, int ididx, int idval);
+
+/**
+ * Delete an object member by object.
+ *
+ */
+void
+hiwire_delete_member_obj(int idobj, int ididx);
+
 /**
  * Call a function
  *
@@ -255,4 +284,62 @@ hiwire_is_function(int idobj);
 int
 hiwire_to_string(int idobj);
 
+/**
+ * Gets the "typeof" string for a value.
+ *
+ * Returns: New reference to Javascript string
+ */
+int
+hiwire_typeof(int idobj);
+
+/**
+ * Returns non-zero if a < b.
+ */
+int
+hiwire_less_than(int ida, int idb);
+
+/**
+ * Returns non-zero if a <= b.
+ */
+int
+hiwire_less_than_equal(int ida, int idb);
+
+/**
+ * Returns non-zero if a == b.
+ */
+int
+hiwire_equal(int ida, int idb);
+
+/**
+ * Returns non-zero if a != b.
+ */
+int
+hiwire_not_equal(int idx, int idb);
+
+/**
+ * Returns non-zero if a > b.
+ */
+int
+hiwire_greater_than(int ida, int idb);
+
+/**
+ * Returns non-zero if a >= b.
+ */
+int
+hiwire_greater_than_equal(int ida, int idb);
+
+/**
+ * Calls the `next` function on an iterator.
+ *
+ * Returns: -1 if `next` function is undefined.
+ */
+int
+hiwire_next(int idobj);
+
+/**
+ * Returns 1 if the value is non-zero.
+ *
+ */
+int hiwire_nonzero(int idobj);
+
 #endif /* HIWIRE_H */

src/jsproxy.c

@@ -49,6 +49,12 @@ JsProxy_GetAttr(PyObject* o, PyObject* attr_name)
   if (strncmp(key, "new", 4) == 0) {
     Py_DECREF(str);
     return PyObject_GenericGetAttr(o, attr_name);
+  } else if (strncmp(key, "typeof", 7) == 0) {
+    Py_DECREF(str);
+    int idval = hiwire_typeof(self->js);
+    PyObject* result = js2python(idval);
+    hiwire_decref(idval);
+    return result;
   }
 
   int idresult = hiwire_get_member_string(self->js, (int)key);
@@ -74,9 +80,14 @@ JsProxy_SetAttr(PyObject* o, PyObject* attr_name, PyObject* pyvalue)
     return -1;
   }
   char* key = PyUnicode_AsUTF8(attr_name_py_str);
-  int idvalue = python2js(pyvalue);
-  hiwire_set_member_string(self->js, (int)key, idvalue);
-  hiwire_decref(idvalue);
+
+  if (pyvalue == NULL) {
+    hiwire_delete_member_string(self->js, (int)key);
+  } else {
+    int idvalue = python2js(pyvalue);
+    hiwire_set_member_string(self->js, (int)key, idvalue);
+    hiwire_decref(idvalue);
+  }
   Py_DECREF(attr_name_py_str);
 
   return 0;
@@ -104,6 +115,84 @@ JsProxy_Call(PyObject* o, PyObject* args, PyObject* kwargs)
   return pyresult;
 }
 
+static PyObject*
+JsProxy_RichCompare(PyObject *a, PyObject *b, int op) {
+  JsProxy* aproxy = (JsProxy*)a;
+
+  if (!JsProxy_Check(b)) {
+    switch (op) {
+    case Py_EQ:
+      Py_RETURN_FALSE;
+    case Py_NE:
+      Py_RETURN_TRUE;
+    default:
+      return Py_NotImplemented;
+    }
+  }
+
+  int result;
+  int ida = python2js(a);
+  int idb = python2js(b);
+  switch (op) {
+  case Py_LT:
+    result = hiwire_less_than(ida, idb);
+    break;
+  case Py_LE:
+    result = hiwire_less_than_equal(ida, idb);
+    break;
+  case Py_EQ:
+    result = hiwire_equal(ida, idb);
+    break;
+  case Py_NE:
+    result = hiwire_not_equal(ida, idb);
+    break;
+  case Py_GT:
+    result = hiwire_greater_than(ida, idb);
+    break;
+  case Py_GE:
+    result = hiwire_greater_than_equal(ida, idb);
+    break;
+  }
+
+  hiwire_decref(ida);
+  hiwire_decref(idb);
+  if (result) {
+    Py_RETURN_TRUE;
+  } else {
+    Py_RETURN_FALSE;
+  }
+}
+
+static PyObject*
+JsProxy_GetIter(PyObject *o)
+{
+  Py_INCREF(o);
+  return o;
+}
+
+static PyObject*
+JsProxy_IterNext(PyObject *o)
+{
+  JsProxy* self = (JsProxy*)o;
+
+  int idresult = hiwire_next(self->js);
+  if (idresult == -1) {
+    return NULL;
+  }
+
+  int iddone = hiwire_get_member_string(idresult, (int)"done");
+  int done = hiwire_nonzero(iddone);
+  hiwire_decref(iddone);
+  if (done) {
+    return NULL;
+  }
+
+  int idvalue = hiwire_get_member_string(idresult, (int)"value");
+  PyObject* pyvalue = js2python(idvalue);
+  hiwire_decref(idvalue);
+  return pyvalue;
+}
+
 static PyObject*
 JsProxy_New(PyObject* o, PyObject* args, PyObject* kwargs)
 {
@@ -135,38 +224,39 @@ JsProxy_length(PyObject* o)
 }
 
 PyObject*
-JsProxy_item(PyObject* o, Py_ssize_t idx)
+JsProxy_subscript(PyObject* o, PyObject* pyidx)
 {
   JsProxy* self = (JsProxy*)o;
 
-  int idresult = hiwire_get_member_int(self->js, idx);
+  int ididx = python2js(pyidx);
+  int idresult = hiwire_get_member_obj(self->js, ididx);
+  hiwire_decref(ididx);
   PyObject* pyresult = js2python(idresult);
   hiwire_decref(idresult);
   return pyresult;
 }
 
 int
-JsProxy_ass_item(PyObject* o, Py_ssize_t idx, PyObject* value)
+JsProxy_ass_subscript(PyObject* o, PyObject* pyidx, PyObject* pyvalue)
 {
   JsProxy* self = (JsProxy*)o;
-  int idvalue = python2js(value);
-  hiwire_set_member_int(self->js, idx, idvalue);
-  hiwire_decref(idvalue);
+  int ididx = python2js(pyidx);
+  if (pyvalue == NULL) {
+    hiwire_delete_member_obj(self->js, ididx);
+  } else {
+    int idvalue = python2js(pyvalue);
+    hiwire_set_member_obj(self->js, ididx, idvalue);
+    hiwire_decref(idvalue);
+  }
+  hiwire_decref(ididx);
   return 0;
 }
 
 // clang-format off
-static PySequenceMethods JsProxy_SequenceMethods = {
+static PyMappingMethods JsProxy_MappingMethods = {
   JsProxy_length,
-  NULL,
-  NULL,
-  JsProxy_item,
-  NULL,
-  JsProxy_ass_item,
-  NULL,
-  NULL,
-  NULL,
-  NULL
+  JsProxy_subscript,
+  JsProxy_ass_subscript,
 };
 // clang-format on
 
@@ -183,10 +273,13 @@ static PyTypeObject JsProxyType = {
   .tp_call = JsProxy_Call,
   .tp_getattro = JsProxy_GetAttr,
   .tp_setattro = JsProxy_SetAttr,
+  .tp_richcompare = JsProxy_RichCompare,
   .tp_flags = Py_TPFLAGS_DEFAULT,
   .tp_doc = "A proxy to make a Javascript object behave like a Python object",
   .tp_methods = JsProxy_Methods,
-  .tp_as_sequence = &JsProxy_SequenceMethods,
+  .tp_as_mapping = &JsProxy_MappingMethods,
+  .tp_iter = JsProxy_GetIter,
+  .tp_iternext = JsProxy_IterNext,
   .tp_repr = JsProxy_Repr
 };
 

test/test_python.py

@@ -172,6 +172,57 @@ def test_jsproxy(selenium):
     assert selenium.run(
         "from js import ImageData\n"
         "ImageData.new(64, 64)")
+    assert selenium.run(
+        "from js import ImageData\n"
+        "ImageData.typeof") == 'function'
+    selenium.run_js(
+        "class Point {\n"
+        "  constructor(x, y) {\n"
+        "    this.x = x;\n"
+        "    this.y = y;\n"
+        "  }\n"
+        "}\n"
+        "window.TEST = new Point(42, 43);")
+    assert selenium.run(
+        "from js import TEST\n"
+        "del TEST.y\n"
+        "TEST.y\n") is None
+    selenium.run_js(
+        "class Point {\n"
+        "  constructor(x, y) {\n"
+        "    this.x = x;\n"
+        "    this.y = y;\n"
+        "  }\n"
+        "}\n"
+        "window.TEST = new Point(42, 43);")
+    assert selenium.run(
+        "from js import TEST\n"
+        "del TEST['y']\n"
+        "TEST['y']\n") is None
+    assert selenium.run(
+        "from js import TEST\n"
+        "TEST == TEST\n")
+    assert selenium.run(
+        "from js import TEST\n"
+        "TEST != 'foo'\n")
+
+
+def test_jsproxy_iter(selenium):
+    selenium.run_js(
+        "function makeIterator(array) {\n"
+        "  var nextIndex = 0;\n"
+        "  return {\n"
+        "    next: function() {\n"
+        "      return nextIndex < array.length ?\n"
+        "        {value: array[nextIndex++], done: false} :\n"
+        "        {done: true};\n"
+        "    }\n"
+        "  };\n"
+        "}\n"
+        "window.ITER = makeIterator([1, 2, 3]);")
+    assert selenium.run(
+        "from js import ITER\n"
+        "list(ITER)") == [1, 2, 3]
 
 
 def test_open_url(selenium):