[librsvg: 26/38] Finish porting the GObject boilerplate to Rust. Yay!!!!!!!

[Federico Mena Quintero <federico src gnome org>]

commit 3f47eeb92dc80987960a0b5ba28d340485633fba
Author: Federico Mena Quintero <federico gnome org>
Date:   Wed Jan 23 14:23:17 2019 -0600

    Finish porting the GObject boilerplate to Rust.  Yay!!!!!!!

 librsvg/rsvg-handle.c              | 240 +------------------------------------
 rsvg_internals/src/c_api.rs        |  27 ++++-
 rsvg_internals/src/handle.rs       |  24 ++--
 rsvg_internals/src/pixbuf_utils.rs |   3 +-
 4 files changed, 37 insertions(+), 257 deletions(-)
---
diff --git a/librsvg/rsvg-handle.c b/librsvg/rsvg-handle.c
index 0fb6beb1..f5281e93 100644
--- a/librsvg/rsvg-handle.c
+++ b/librsvg/rsvg-handle.c
@@ -197,236 +197,13 @@ extern RsvgHandle *rsvg_handle_rust_new_from_data (const guint8 *data,
                                                    gsize data_len,
                                                    GError **error);
 
-typedef struct {
-    RsvgHandleRust *rust_handle;
-} RsvgHandlePrivate;
-
-enum {
-    PROP_0,
-    PROP_FLAGS,
-    PROP_DPI_X,
-    PROP_DPI_Y,
-    PROP_BASE_URI,
-    PROP_WIDTH,
-    PROP_HEIGHT,
-    PROP_EM,
-    PROP_EX,
-    PROP_TITLE,
-    PROP_DESC,
-    PROP_METADATA,
-    NUM_PROPS
-};
-
-G_DEFINE_TYPE_WITH_CODE (RsvgHandle, rsvg_handle, G_TYPE_OBJECT,
-                         G_ADD_PRIVATE (RsvgHandle))
-
-static void
-rsvg_handle_init (RsvgHandle *self)
-{
-    RsvgHandlePrivate *priv = rsvg_handle_get_instance_private (self);
-    priv->rust_handle = rsvg_handle_rust_new();
-}
-
-static void
-rsvg_handle_dispose (GObject *instance)
-{
-    RsvgHandle *self = (RsvgHandle *) instance;
-    RsvgHandlePrivate *priv = rsvg_handle_get_instance_private (self);
-
-    g_clear_pointer (&priv->rust_handle, rsvg_handle_rust_free);
-
-    G_OBJECT_CLASS (rsvg_handle_parent_class)->dispose (instance);
-}
-
-static void
-rsvg_handle_set_property (GObject * instance, guint prop_id, GValue const *value, GParamSpec * pspec)
-{
-    RsvgHandle *self = RSVG_HANDLE (instance);
-
-    switch (prop_id) {
-    case PROP_FLAGS:
-        rsvg_handle_rust_set_flags (self, g_value_get_flags (value));
-        break;
-    case PROP_DPI_X:
-        rsvg_handle_rust_set_dpi_x (self, g_value_get_double (value));
-        break;
-    case PROP_DPI_Y:
-        rsvg_handle_rust_set_dpi_y (self, g_value_get_double (value));
-        break;
-    case PROP_BASE_URI: {
-        const char *str = g_value_get_string (value);
-
-        if (str) {
-            rsvg_handle_set_base_uri (self, str);
-        }
-
-        break;
-    }
-    default:
-        G_OBJECT_WARN_INVALID_PROPERTY_ID (instance, prop_id, pspec);
-    }
-}
-
-static void
-rsvg_handle_get_property (GObject * instance, guint prop_id, GValue * value, GParamSpec * pspec)
-{
-    RsvgHandle *self = RSVG_HANDLE (instance);
-    RsvgDimensionData dim;
-
-    switch (prop_id) {
-    case PROP_FLAGS:
-        g_value_set_flags (value, rsvg_handle_rust_get_flags (self));
-        break;
-    case PROP_DPI_X:
-        g_value_set_double (value, rsvg_handle_rust_get_dpi_x (self));
-        break;
-    case PROP_DPI_Y:
-        g_value_set_double (value, rsvg_handle_rust_get_dpi_y (self));
-        break;
-    case PROP_BASE_URI:
-        g_value_set_string (value, rsvg_handle_get_base_uri (self));
-        break;
-    case PROP_WIDTH:
-        rsvg_handle_get_dimensions (self, &dim);
-        g_value_set_int (value, dim.width);
-        break;
-    case PROP_HEIGHT:
-        rsvg_handle_get_dimensions (self, &dim);
-        g_value_set_int (value, dim.height);
-        break;
-    case PROP_EM:
-        rsvg_handle_get_dimensions (self, &dim);
-        g_value_set_double (value, dim.em);
-        break;
-    case PROP_EX:
-        rsvg_handle_get_dimensions (self, &dim);
-        g_value_set_double (value, dim.ex);
-        break;
-    case PROP_TITLE:
-        /* deprecated */
-        break;
-    case PROP_DESC:
-        /* deprecated */
-        break;
-    case PROP_METADATA:
-        g_value_set_string (value, rsvg_handle_get_metadata (self));
-        break;
-    default:
-        G_OBJECT_WARN_INVALID_PROPERTY_ID (instance, prop_id, pspec);
-    }
-}
+/* Implemented in rsvg_internals/src/c_api.rs */
+extern GType rsvg_handle_rust_get_type (void);
 
-static void
-rsvg_handle_class_init (RsvgHandleClass * klass)
+GType
+rsvg_handle_get_type (void)
 {
-    GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
-
-    gobject_class->dispose = rsvg_handle_dispose;
-    gobject_class->set_property = rsvg_handle_set_property;
-    gobject_class->get_property = rsvg_handle_get_property;
-
-    /**
-     * RsvgHandle:flags:
-     *
-     * Flags from #RsvgHandleFlags.
-     *
-     * Since: 2.36
-     */
-    g_object_class_install_property (gobject_class,
-                                     PROP_FLAGS,
-                                     g_param_spec_flags ("flags", NULL, NULL,
-                                                         RSVG_TYPE_HANDLE_FLAGS,
-                                                         RSVG_HANDLE_FLAGS_NONE,
-                                                         G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY));
-
-    /**
-     * dpi-x:
-     */
-    g_object_class_install_property (gobject_class,
-                                     PROP_DPI_X,
-                                     g_param_spec_double ("dpi-x", _("Horizontal resolution"),
-                                                          _("Horizontal resolution"),
-                                                          0., G_MAXDOUBLE, 0.,
-                                                          (GParamFlags) (G_PARAM_READWRITE |
-                                                                         G_PARAM_CONSTRUCT)));
-
-    g_object_class_install_property (gobject_class,
-                                     PROP_DPI_Y,
-                                     g_param_spec_double ("dpi-y", _("Vertical resolution"),
-                                                          _("Vertical resolution"),
-                                                          0., G_MAXDOUBLE, 0.,
-                                                          (GParamFlags) (G_PARAM_READWRITE |
-                                                                         G_PARAM_CONSTRUCT)));
-
-    g_object_class_install_property (gobject_class,
-                                     PROP_BASE_URI,
-                                     g_param_spec_string ("base-uri", _("Base URI"),
-                                                          _("Base URI"), NULL,
-                                                          (GParamFlags) (G_PARAM_READWRITE |
-                                                                         G_PARAM_CONSTRUCT)));
-
-    g_object_class_install_property (gobject_class,
-                                     PROP_WIDTH,
-                                     g_param_spec_int ("width", _("Image width"),
-                                                       _("Image width"), 0, G_MAXINT, 0,
-                                                       (GParamFlags) (G_PARAM_READABLE)));
-
-    g_object_class_install_property (gobject_class,
-                                     PROP_HEIGHT,
-                                     g_param_spec_int ("height", _("Image height"),
-                                                       _("Image height"), 0, G_MAXINT, 0,
-                                                       (GParamFlags) (G_PARAM_READABLE)));
-
-    g_object_class_install_property (gobject_class,
-                                     PROP_EM,
-                                     g_param_spec_double ("em", _("em"),
-                                                          _("em"), 0, G_MAXDOUBLE, 0,
-                                                          (GParamFlags) (G_PARAM_READABLE)));
-
-    g_object_class_install_property (gobject_class,
-                                     PROP_EX,
-                                     g_param_spec_double ("ex", _("ex"),
-                                                          _("ex"), 0, G_MAXDOUBLE, 0,
-                                                          (GParamFlags) (G_PARAM_READABLE)));
-
-    /**
-     * RsvgHandle:title:
-     *
-     * SVG's description
-     *
-     * Deprecated: 2.36
-     */
-    g_object_class_install_property (gobject_class,
-                                     PROP_TITLE,
-                                     g_param_spec_string ("title", _("Title"),
-                                                          _("SVG file title"), NULL,
-                                                          (GParamFlags) (G_PARAM_READABLE)));
-
-    /**
-     * RsvgHandle:desc:
-     *
-     * SVG's description
-     *
-     * Deprecated: 2.36
-     */
-    g_object_class_install_property (gobject_class,
-                                     PROP_DESC,
-                                     g_param_spec_string ("desc", _("Description"),
-                                                          _("SVG file description"), NULL,
-                                                          (GParamFlags) (G_PARAM_READABLE)));
-
-    /**
-     * RsvgHandle:metadata:
-     *
-     * SVG's description
-     *
-     * Deprecated: 2.36
-     */
-    g_object_class_install_property (gobject_class,
-                                     PROP_METADATA,
-                                     g_param_spec_string ("metadata", _("Metadata"),
-                                                          _("SVG file metadata"), NULL,
-                                                          (GParamFlags) (G_PARAM_READABLE)));
+    return rsvg_handle_rust_get_type ();
 }
 
 /**
@@ -796,13 +573,6 @@ rsvg_handle_get_desc (RsvgHandle * handle)
     return NULL;
 }
 
-RsvgHandleRust *
-rsvg_handle_get_rust (RsvgHandle *handle)
-{
-    RsvgHandlePrivate *priv = rsvg_handle_get_instance_private (handle);
-    return priv->rust_handle;
-}
-
 /**
  * rsvg_handle_render_cairo_sub:
  * @handle: A #RsvgHandle
diff --git a/rsvg_internals/src/c_api.rs b/rsvg_internals/src/c_api.rs
index b4979c81..992338e9 100644
--- a/rsvg_internals/src/c_api.rs
+++ b/rsvg_internals/src/c_api.rs
@@ -243,7 +243,15 @@ impl ObjectImpl for Handle {
             }
 
             subclass::Property("base-uri", ..) => {
-                self.set_base_url(value.get().expect("base-uri should be a non-NULL string"));
+                let v: Option<String> = value.get();;
+
+                // rsvg_handle_set_base_uri() expects non-NULL URI strings,
+                // but the "base-uri" property can be set to NULL due to a missing
+                // construct-time property.
+
+                if let Some(s) = v {
+                    self.set_base_url(&s);
+                }
             }
 
             _ => unreachable!("invalid property id {}", id),
@@ -273,11 +281,22 @@ impl ObjectImpl for Handle {
             subclass::Property("em", ..) => Ok(self.get_dimensions_no_error().em.to_value()),
             subclass::Property("ex", ..) => Ok(self.get_dimensions_no_error().ex.to_value()),
 
-            subclass::Property("title", ..) => Ok("".to_value()), // deprecated
-            subclass::Property("desc", ..) => Ok("".to_value()),  // deprecated
-            subclass::Property("metadata", ..) => Ok("".to_value()), // deprecated
+            // the following three are deprecated
+            subclass::Property("title", ..) => Ok((None as Option<String>).to_value()),
+            subclass::Property("desc", ..) => Ok((None as Option<String>).to_value()),
+            subclass::Property("metadata", ..) => Ok((None as Option<String>).to_value()),
 
             _ => unreachable!("invalid property id={} for RsvgHandle", id),
         }
     }
 }
+
+pub fn get_rust_handle<'a>(handle: *const RsvgHandle) -> &'a Handle {
+    let handle = unsafe { &*handle };
+    handle.get_impl()
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn rsvg_handle_rust_get_type() -> glib_sys::GType {
+    Handle::get_type().to_glib()
+}
diff --git a/rsvg_internals/src/handle.rs b/rsvg_internals/src/handle.rs
index d7d14897..3492c366 100644
--- a/rsvg_internals/src/handle.rs
+++ b/rsvg_internals/src/handle.rs
@@ -13,6 +13,7 @@ use gdk_pixbuf::Pixbuf;
 use gdk_pixbuf_sys;
 use gio::{self, FileExt};
 use gio_sys;
+use glib::subclass::types::ObjectSubclass;
 use glib::translate::*;
 use glib::{self, Bytes, Cast};
 use glib_sys;
@@ -21,7 +22,7 @@ use libc;
 use url::Url;
 
 use allowed_url::{AllowedUrl, Href};
-use c_api::{HandleFlags, RsvgHandle, RsvgHandleFlags};
+use c_api::{get_rust_handle, HandleFlags, RsvgHandle, RsvgHandleFlags};
 use dpi::Dpi;
 use drawing_ctx::{DrawingCtx, RsvgRectangle};
 use error::{set_gerror, DefsLookupErrorKind, LoadingError, RenderingError};
@@ -35,10 +36,10 @@ use xml::XmlState;
 use xml2_load::xml_state_load_from_possibly_compressed_stream;
 
 // A *const RsvgHandle is just an opaque pointer we get from C
-#[repr(C)]
-pub struct RsvgHandle {
-    _private: [u8; 0],
-}
+// #[repr(C)]
+// pub struct RsvgHandle {
+//    _private: [u8; 0],
+// }
 
 // Keep in sync with rsvg.h:RsvgDimensionData
 #[repr(C)]
@@ -656,13 +657,6 @@ impl LoadFlags {
     }
 }
 
-#[allow(improper_ctypes)]
-extern "C" {
-    fn rsvg_handle_get_type() -> glib_sys::GType;
-
-    fn rsvg_handle_get_rust(handle: *const RsvgHandle) -> *const Handle;
-}
-
 #[no_mangle]
 pub unsafe extern "C" fn rsvg_handle_rust_new() -> *mut Handle {
     Box::into_raw(Box::new(Handle::new()))
@@ -674,10 +668,6 @@ pub unsafe extern "C" fn rsvg_handle_rust_free(raw_handle: *mut Handle) {
     Box::from_raw(raw_handle);
 }
 
-pub fn get_rust_handle<'a>(handle: *const RsvgHandle) -> &'a Handle {
-    unsafe { &*rsvg_handle_get_rust(handle) }
-}
-
 #[no_mangle]
 pub unsafe extern "C" fn rsvg_handle_rust_set_base_url(
     raw_handle: *const RsvgHandle,
@@ -1030,7 +1020,7 @@ pub unsafe extern "C" fn rsvg_handle_rust_get_position_sub(
 #[no_mangle]
 pub unsafe extern "C" fn rsvg_handle_rust_new_with_flags(flags: u32) -> *const RsvgHandle {
     let obj: *mut gobject_sys::GObject =
-        glib::Object::new(from_glib(rsvg_handle_get_type()), &[("flags", &flags)])
+        glib::Object::new(Handle::get_type(), &[("flags", &flags)])
             .unwrap()
             .to_glib_full();
 
diff --git a/rsvg_internals/src/pixbuf_utils.rs b/rsvg_internals/src/pixbuf_utils.rs
index 1324fa69..1bea47c9 100644
--- a/rsvg_internals/src/pixbuf_utils.rs
+++ b/rsvg_internals/src/pixbuf_utils.rs
@@ -7,8 +7,9 @@ use glib::translate::*;
 use glib_sys;
 use libc;
 
+use c_api::get_rust_handle;
 use error::{set_gerror, RenderingError};
-use handle::{get_rust_handle, rsvg_handle_rust_new_from_gfile_sync, Handle, RsvgDimensionData};
+use handle::{rsvg_handle_rust_new_from_gfile_sync, Handle, RsvgDimensionData};
 use rect::IRect;
 use surface_utils::{
     iterators::Pixels,