[gjs: 6/12] cairo: Remove JSClass macros from Cairo context

[Philip Chimento <pchimento src gnome org>]

commit e15f239b9ff528bb473b83a7e57313236d4a76b7
Author: Philip Chimento <philip chimento gmail com>
Date:   Tue May 5 22:30:12 2020 -0700

    cairo: Remove JSClass macros from Cairo context
    
    Remove the usage of the GJS_DEFINE_PRIV_FROM_JS and GJS_DEFINE_PROTO
    families of macros from the Cairo context wrapper type. Use CWrapper
    instead, for more type safety and less boilerplate.
    
    Also requires adding a debug topic for Cairo.

 modules/cairo-context.cpp | 98 +++++++++++------------------------------------
 modules/cairo-private.h   | 62 +++++++++++++++++++++++++-----
 modules/cairo.cpp         |  2 +-
 util/log.cpp              |  3 ++
 util/log.h                |  1 +
 5 files changed, 80 insertions(+), 86 deletions(-)
---
diff --git a/modules/cairo-context.cpp b/modules/cairo-context.cpp
index 3654cae4..b1693239 100644
--- a/modules/cairo-context.cpp
+++ b/modules/cairo-context.cpp
@@ -6,14 +6,12 @@
 
 #include <vector>
 
-#include <cairo-gobject.h>
 #include <cairo.h>
 #include <girepository.h>
 #include <glib.h>
 
 #include <js/Array.h>  // for JS::NewArrayObject
 #include <js/CallArgs.h>
-#include <js/Class.h>
 #include <js/Conversions.h>
 #include <js/PropertyDescriptor.h>  // for JSPROP_READONLY
 #include <js/PropertySpec.h>
@@ -28,17 +26,16 @@
 #include "gi/arg.h"
 #include "gi/foreign.h"
 #include "gjs/enum-utils.h"
-#include "gjs/jsapi-class.h"
 #include "gjs/jsapi-util-args.h"
 #include "gjs/jsapi-util.h"
 #include "gjs/macros.h"
 #include "modules/cairo-private.h"
 
-struct GjsCairoContext;
-
 #define _GJS_CAIRO_CONTEXT_GET_PRIV_CR_CHECKED(cx, argc, vp, argv, obj) \
-    GJS_GET_PRIV(context, argc, vp, argv, obj, GjsCairoContext, priv);  \
-    cairo_t* cr = priv->get();                                          \
+    GJS_GET_THIS(cx, argc, vp, argv, obj);                              \
+    cairo_t* cr;                                                        \
+    if (!CairoContext::for_js_typecheck(cx, obj, &cr, &argv))           \
+        return false;                                                   \
     if (!cr)                                                            \
         return true;
 
@@ -248,64 +245,38 @@ _GJS_CAIRO_CONTEXT_DEFINE_FUNC_BEGIN(method)                               \
     argv.rval().setUndefined();                                            \
 _GJS_CAIRO_CONTEXT_DEFINE_FUNC_END
 
-[[nodiscard]] static JSObject* gjs_cairo_context_get_proto(JSContext*);
-
-struct GjsCairoContext
-    : GjsAutoPointer<cairo_t, cairo_t, cairo_destroy, cairo_reference> {
-    explicit GjsCairoContext(cairo_t* cr)
-        : GjsAutoPointer(cr, GjsAutoTakeOwnership()) {}
-};
-
-GJS_DEFINE_PROTO_WITH_GTYPE("Context", cairo_context,
-                            CAIRO_GOBJECT_TYPE_CONTEXT,
-                            JSCLASS_BACKGROUND_FINALIZE)
-GJS_DEFINE_PRIV_FROM_JS(GjsCairoContext, gjs_cairo_context_class);
-
-static void _gjs_cairo_context_construct_internal(JSContext* context,
-                                                  JS::HandleObject obj,
-                                                  cairo_t* cr) {
-    g_assert(!priv_from_js(context, obj));
-    JS_SetPrivate(obj, new GjsCairoContext(cr));
-}
-
-GJS_NATIVE_CONSTRUCTOR_DECLARE(cairo_context)
-{
-    GJS_NATIVE_CONSTRUCTOR_VARIABLES(cairo_context)
+GJS_JSAPI_RETURN_CONVENTION
+cairo_t* CairoContext::constructor_impl(JSContext* context,
+                                        const JS::CallArgs& argv) {
     cairo_t *cr;
 
-    GJS_NATIVE_CONSTRUCTOR_PRELUDE(cairo_context);
-
     JS::RootedObject surface_wrapper(context);
     if (!gjs_parse_call_args(context, "Context", argv, "o",
                              "surface", &surface_wrapper))
-        return false;
+        return nullptr;
 
     cairo_surface_t* surface =
         gjs_cairo_surface_get_surface(context, surface_wrapper);
     if (!surface)
-        return false;
+        return nullptr;
 
     cr = cairo_create(surface);
 
     if (!gjs_cairo_check_status(context, cairo_status(cr), "context"))
-        return false;
-
-    _gjs_cairo_context_construct_internal(context, object, cr);
-    cairo_destroy(cr);
-
-    GJS_NATIVE_CONSTRUCTOR_FINISH(cairo_context);
+        return nullptr;
 
-    return true;
+    return cr;
 }
 
-static void gjs_cairo_context_finalize(JSFreeOp*, JSObject* obj) {
-    delete static_cast<GjsCairoContext*>(JS_GetPrivate(obj));
-    JS_SetPrivate(obj, nullptr);
+void CairoContext::finalize_impl(JSFreeOp*, cairo_t* cr) {
+    if (!cr)
+        return;
+    cairo_destroy(cr);
 }
 
 /* Properties */
 // clang-format off
-JSPropertySpec gjs_cairo_context_proto_props[] = {
+const JSPropertySpec CairoContext::proto_props[] = {
     JS_STRING_SYM_PS(toStringTag, "Context", JSPROP_READONLY),
     JS_PS_END};
 // clang-format on
@@ -820,7 +791,8 @@ getGroupTarget_func(JSContext *context,
     return true;
 }
 
-JSFunctionSpec gjs_cairo_context_proto_funcs[] = {
+// clang-format off
+const JSFunctionSpec CairoContext::proto_funcs[] = {
     JS_FN("$dispose", dispose_func, 0, 0),
     JS_FN("appendPath", appendPath_func, 0, 0),
     JS_FN("arc", arc_func, 0, 0),
@@ -920,31 +892,7 @@ JSFunctionSpec gjs_cairo_context_proto_funcs[] = {
     JS_FN("userToDevice", userToDevice_func, 0, 0),
     JS_FN("userToDeviceDistance", userToDeviceDistance_func, 0, 0),
     JS_FS_END};
-
-JSFunctionSpec gjs_cairo_context_static_funcs[] = { JS_FS_END };
-
-JSObject *
-gjs_cairo_context_from_context(JSContext *context,
-                               cairo_t *cr)
-{
-    JS::RootedObject proto(context, gjs_cairo_context_get_proto(context));
-    JS::RootedObject object(context,
-        JS_NewObjectWithGivenProto(context, &gjs_cairo_context_class, proto));
-    if (!object)
-        return nullptr;
-
-    _gjs_cairo_context_construct_internal(context, object, cr);
-
-    return object;
-}
-
-cairo_t *
-gjs_cairo_context_get_context(JSContext       *context,
-                              JS::HandleObject object)
-{
-    auto* priv = priv_from_js(context, object);
-    return priv ? priv->get() : nullptr;
-}
+// clang-format on
 
 [[nodiscard]] static bool context_to_g_argument(
     JSContext* context, JS::Value value, const char* arg_name,
@@ -963,9 +911,7 @@ gjs_cairo_context_get_context(JSContext       *context,
     }
 
     JS::RootedObject obj(context, &value.toObject());
-    cairo_t *cr;
-
-    cr = gjs_cairo_context_get_context(context, obj);
+    cairo_t* cr = CairoContext::for_js(context, obj);
     if (!cr)
         return false;
     if (transfer == GI_TRANSFER_EVERYTHING)
@@ -981,8 +927,8 @@ context_from_g_argument(JSContext             *context,
                         JS::MutableHandleValue value_p,
                         GIArgument            *arg)
 {
-    JSObject* obj =
-        gjs_cairo_context_from_context(context, gjs_arg_get<cairo_t*>(arg));
+    JSObject* obj = CairoContext::from_c_ptr(
+        context, static_cast<cairo_t*>(arg->v_pointer));
     if (!obj) {
         gjs_throw(context, "Could not create Cairo context");
         return false;
diff --git a/modules/cairo-private.h b/modules/cairo-private.h
index f3f1aec3..601632b1 100644
--- a/modules/cairo-private.h
+++ b/modules/cairo-private.h
@@ -1,6 +1,7 @@
 /* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil; -*- */
 // SPDX-License-Identifier: MIT OR LGPL-2.0-or-later
 // SPDX-FileCopyrightText: 2010 litl, LLC.
+// SPDX-FileCopyrightText: 2020 Philip Chimento <philip chimento gmail com>
 
 #ifndef MODULES_CAIRO_PRIVATE_H_
 #define MODULES_CAIRO_PRIVATE_H_
@@ -8,11 +9,26 @@
 #include <config.h>
 
 #include <cairo-features.h>  // for CAIRO_HAS_PDF_SURFACE, CAIRO_HAS_PS_SURFACE
+#include <cairo-gobject.h>
 #include <cairo.h>
+#include <glib-object.h>
 
+#include <js/PropertySpec.h>
 #include <js/TypeDecls.h>
 
+#include "gi/cwrapper.h"
+#include "gi/wrapperutils.h"
+#include "gjs/global.h"
 #include "gjs/macros.h"
+#include "util/log.h"
+
+namespace JS {
+class CallArgs;
+}
+namespace js {
+struct ClassSpec;
+}
+struct JSClass;
 
 GJS_JSAPI_RETURN_CONVENTION
 bool             gjs_cairo_check_status                 (JSContext       *context,
@@ -26,16 +42,44 @@ bool gjs_cairo_region_define_proto(JSContext              *cx,
 
 void gjs_cairo_region_init(void);
 
-GJS_JSAPI_RETURN_CONVENTION
-bool gjs_cairo_context_define_proto(JSContext              *cx,
-                                    JS::HandleObject        module,
-                                    JS::MutableHandleObject proto);
+class CairoContext : public CWrapper<CairoContext, cairo_t> {
+    friend CWrapperPointerOps<CairoContext, cairo_t>;
+    friend CWrapper<CairoContext, cairo_t>;
+
+    CairoContext() = delete;
+    CairoContext(CairoContext&) = delete;
+    CairoContext(CairoContext&&) = delete;
+
+    static constexpr GjsGlobalSlot PROTOTYPE_SLOT =
+        GjsGlobalSlot::PROTOTYPE_cairo_context;
+    static constexpr GjsDebugTopic DEBUG_TOPIC = GJS_DEBUG_CAIRO;
+    static constexpr unsigned constructor_nargs = 1;
+
+    static GType gtype() { return CAIRO_GOBJECT_TYPE_CONTEXT; }
+
+    static cairo_t* copy_ptr(cairo_t* cr) { return cairo_reference(cr); }
+
+    GJS_JSAPI_RETURN_CONVENTION
+    static cairo_t* constructor_impl(JSContext* cx, const JS::CallArgs& args);
+
+    static void finalize_impl(JSFreeOp* fop, cairo_t* cr);
+
+    static const JSFunctionSpec proto_funcs[];
+    static const JSPropertySpec proto_props[];
+    static constexpr js::ClassSpec class_spec = {
+        nullptr,  // createConstructor
+        nullptr,  // createPrototype
+        nullptr,  // constructorFunctions
+        nullptr,  // constructorProperties
+        CairoContext::proto_funcs,
+        CairoContext::proto_props,
+        CairoContext::define_gtype_prop,
+    };
+    static constexpr JSClass klass = {
+        "Context", JSCLASS_HAS_PRIVATE | JSCLASS_BACKGROUND_FINALIZE,
+        &CairoContext::class_ops, &CairoContext::class_spec};
+};
 
-[[nodiscard]] cairo_t* gjs_cairo_context_get_context(JSContext* cx,
-                                                     JS::HandleObject object);
-GJS_JSAPI_RETURN_CONVENTION
-JSObject *       gjs_cairo_context_from_context         (JSContext       *context,
-                                                         cairo_t         *cr);
 void gjs_cairo_context_init(void);
 void gjs_cairo_surface_init(void);
 
diff --git a/modules/cairo.cpp b/modules/cairo.cpp
index 172de91c..c2d3e764 100644
--- a/modules/cairo.cpp
+++ b/modules/cairo.cpp
@@ -61,7 +61,7 @@ gjs_js_define_cairo_stuff(JSContext              *context,
         return false;
     gjs_cairo_region_init();
 
-    if (!gjs_cairo_context_define_proto(context, module, &proto))
+    if (!CairoContext::create_prototype(context, module))
         return false;
     gjs_cairo_context_init();
 
diff --git a/util/log.cpp b/util/log.cpp
index 9ecb866d..728d4c50 100644
--- a/util/log.cpp
+++ b/util/log.cpp
@@ -166,6 +166,9 @@ _Pragma("GCC diagnostic pop")
     case GJS_DEBUG_NATIVE:
         prefix = "JS NATIVE";
         break;
+    case GJS_DEBUG_CAIRO:
+        prefix = "JS CAIRO";
+        break;
     case GJS_DEBUG_KEEP_ALIVE:
         prefix = "JS KP ALV";
         break;
diff --git a/util/log.h b/util/log.h
index b487d898..9dd1f43f 100644
--- a/util/log.h
+++ b/util/log.h
@@ -18,6 +18,7 @@ typedef enum {
     GJS_DEBUG_CONTEXT,
     GJS_DEBUG_IMPORTER,
     GJS_DEBUG_NATIVE,
+    GJS_DEBUG_CAIRO,
     GJS_DEBUG_KEEP_ALIVE,
     GJS_DEBUG_GREPO,
     GJS_DEBUG_GNAMESPACE,