[librsvg/rustification] Make rsvg_state_new() / rsvg_state_free() the only way of getting new states

[Federico Mena Quintero <federico src gnome org>]

commit 468f9251782b7aed6f9ff5e34e404a6da161e880
Author: Federico Mena Quintero <federico gnome org>
Date:   Wed Nov 9 15:37:27 2016 -0600

    Make rsvg_state_new() / rsvg_state_free() the only way of getting new states
    
    Previously they were allocated on the stack, allocated by hand on the
    heap, allocated with g_slice by rsvg_state_push()...
    
    Make all of that consistent; rsvg_state_new() is the only way to get
    a new state now.

 rsvg-image.c        |    4 +-
 rsvg-paint-server.c |   15 ++++---
 rsvg-structure.c    |   11 +++--
 rsvg-styles.c       |  125 ++++++++++++++++++++++++++++++---------------------
 rsvg-styles.h       |    5 +-
 5 files changed, 91 insertions(+), 69 deletions(-)
---
diff --git a/rsvg-image.c b/rsvg-image.c
index 700aa79..69127e3 100644
--- a/rsvg-image.c
+++ b/rsvg-image.c
@@ -155,9 +155,7 @@ static void
 rsvg_node_image_free (RsvgNode * self)
 {
     RsvgNodeImage *z = (RsvgNodeImage *) self;
-    rsvg_state_finalize (z->super.state);
-    g_free (z->super.state);
-    z->super.state = NULL;
+
     if (z->surface)
         cairo_surface_destroy (z->surface);
     _rsvg_node_free(self);
diff --git a/rsvg-paint-server.c b/rsvg-paint-server.c
index 1bbb4cb..ebf24bb 100644
--- a/rsvg-paint-server.c
+++ b/rsvg-paint-server.c
@@ -153,7 +153,7 @@ rsvg_stop_set_atts (RsvgNode * self, RsvgHandle * ctx, RsvgPropertyBag * atts)
     gboolean is_current_color = FALSE;
     const char *value;
     RsvgGradientStop *stop;
-    RsvgState state;
+    RsvgState *state;
 
     stop = (RsvgGradientStop *) self;
 
@@ -179,12 +179,15 @@ rsvg_stop_set_atts (RsvgNode * self, RsvgHandle * ctx, RsvgPropertyBag * atts)
         rsvg_parse_style_pairs (ctx, self->state, atts);
     }
     self->parent = ctx->priv->currentnode;
-    rsvg_state_init (&state);
-    rsvg_state_reconstruct (&state, self);
+
+    state = rsvg_state_new ();
+    rsvg_state_reconstruct (state, self);
+
     if (is_current_color)
-        state.stop_color = state.current_color;
-    stop->rgba = (state.stop_color << 8) | state.stop_opacity;
-    rsvg_state_finalize (&state);
+        state->stop_color = state->current_color;
+    stop->rgba = (state->stop_color << 8) | state->stop_opacity;
+
+    rsvg_state_free (state);
 }
 
 RsvgNode *
diff --git a/rsvg-structure.c b/rsvg-structure.c
index c494cf5..cf9e9c5 100644
--- a/rsvg-structure.c
+++ b/rsvg-structure.c
@@ -92,8 +92,7 @@ _rsvg_node_init (RsvgNode * self,
     self->type = type;
     self->parent = NULL;
     self->children = g_ptr_array_new ();
-    self->state = g_new (RsvgState, 1);
-    rsvg_state_init (self->state);
+    self->state = rsvg_state_new ();
     self->free = _rsvg_node_free;
     self->draw = _rsvg_node_draw_nothing;
     self->set_atts = _rsvg_node_dont_set_atts;
@@ -103,11 +102,13 @@ void
 _rsvg_node_finalize (RsvgNode * self)
 {
     if (self->state != NULL) {
-        rsvg_state_finalize (self->state);
-        g_free (self->state);
+        rsvg_state_free (self->state);
+        self->state = NULL;
     }
-    if (self->children != NULL)
+    if (self->children != NULL) {
         g_ptr_array_free (self->children, TRUE);
+        self->children = NULL;
+    }
 }
 
 void
diff --git a/rsvg-styles.c b/rsvg-styles.c
index 6e91981..ee302f0 100644
--- a/rsvg-styles.c
+++ b/rsvg-styles.c
@@ -114,7 +114,7 @@ rsvg_dpi_percentage (RsvgHandle * ctx)
     return sqrt (ctx->priv->dpi_x * ctx->priv->dpi_y);
 }
 
-void
+static void
 rsvg_state_init (RsvgState * state)
 {
     memset (state, 0, sizeof (RsvgState));
@@ -211,6 +211,71 @@ rsvg_state_init (RsvgState * state)
                                            g_free, (GDestroyNotify) style_value_data_free);
 }
 
+RsvgState *
+rsvg_state_new (void)
+{
+    RsvgState *state;
+
+    state = g_slice_new (RsvgState);
+    rsvg_state_init (state);
+
+    return state;
+}
+
+static void
+rsvg_state_finalize (RsvgState * state)
+{
+    g_free (state->filter);
+    state->filter = NULL;
+
+    g_free (state->mask);
+    state->mask = NULL;
+
+    g_free (state->clip_path);
+    state->clip_path = NULL;
+
+    g_free (state->font_family);
+    state->font_family = NULL;
+
+    g_free (state->lang);
+    state->lang = NULL;
+
+    g_free (state->startMarker);
+    state->startMarker = NULL;
+
+    g_free (state->middleMarker);
+    state->middleMarker = NULL;
+
+    g_free (state->endMarker);
+    state->endMarker = NULL;
+
+    rsvg_paint_server_unref (state->fill);
+    state->fill = NULL;
+
+    rsvg_paint_server_unref (state->stroke);
+    state->stroke = NULL;
+
+    if (state->dash.n_dash != 0) {
+        g_free (state->dash.dash);
+        state->dash.n_dash = 0;
+        state->dash.dash = NULL;
+    }
+
+    if (state->styles) {
+        g_hash_table_unref (state->styles);
+        state->styles = NULL;
+    }
+}
+
+void
+rsvg_state_free (RsvgState *state)
+{
+    g_assert (state != NULL);
+
+    rsvg_state_finalize (state);
+    g_slice_free (RsvgState, state);
+}
+
 void
 rsvg_state_reinit (RsvgState * state)
 {
@@ -468,51 +533,6 @@ rsvg_state_inherit (RsvgState * dst, const RsvgState * src)
     rsvg_state_inherit_run (dst, src, inheritfunction, 1);
 }
 
-void
-rsvg_state_finalize (RsvgState * state)
-{
-    g_free (state->filter);
-    state->filter = NULL;
-
-    g_free (state->mask);
-    state->mask = NULL;
-
-    g_free (state->clip_path);
-    state->clip_path = NULL;
-
-    g_free (state->font_family);
-    state->font_family = NULL;
-
-    g_free (state->lang);
-    state->lang = NULL;
-
-    g_free (state->startMarker);
-    state->startMarker = NULL;
-
-    g_free (state->middleMarker);
-    state->middleMarker = NULL;
-
-    g_free (state->endMarker);
-    state->endMarker = NULL;
-
-    rsvg_paint_server_unref (state->fill);
-    state->fill = NULL;
-
-    rsvg_paint_server_unref (state->stroke);
-    state->stroke = NULL;
-
-    if (state->dash.n_dash != 0) {
-        g_free (state->dash.dash);
-        state->dash.n_dash = 0;
-        state->dash.dash = NULL;
-    }
-
-    if (state->styles) {
-        g_hash_table_unref (state->styles);
-        state->styles = NULL;
-    }
-}
-
 /* Parse a CSS2 style argument, setting the SVG context attributes. */
 static void
 rsvg_parse_style_pair (RsvgHandle * ctx,
@@ -1560,8 +1580,9 @@ rsvg_state_free_all (RsvgState * state)
 {
     while (state) {
         RsvgState *parent = state->parent;
-        rsvg_state_finalize (state);
-        g_slice_free (RsvgState, state);
+
+        rsvg_state_free (state);
+
         state = parent;
     }
 }
@@ -1650,8 +1671,7 @@ rsvg_state_push (RsvgDrawingCtx * ctx)
     RsvgState *baseon;
 
     baseon = ctx->state;
-    data = g_slice_new (RsvgState);
-    rsvg_state_init (data);
+    data = rsvg_state_new ();
 
     if (baseon) {
         rsvg_state_reinherit (data, baseon);
@@ -1666,9 +1686,10 @@ void
 rsvg_state_pop (RsvgDrawingCtx * ctx)
 {
     RsvgState *dead_state = ctx->state;
+
     ctx->state = dead_state->parent;
-    rsvg_state_finalize (dead_state);
-    g_slice_free (RsvgState, dead_state);
+
+    rsvg_state_free (dead_state);
 }
 
 /*
diff --git a/rsvg-styles.h b/rsvg-styles.h
index a044d3f..bad0425 100644
--- a/rsvg-styles.h
+++ b/rsvg-styles.h
@@ -191,7 +191,8 @@ G_GNUC_INTERNAL
 RsvgState *rsvg_state_new (void);
 
 G_GNUC_INTERNAL
-void rsvg_state_init        (RsvgState * state);
+void rsvg_state_free (RsvgState *state);
+
 G_GNUC_INTERNAL
 void rsvg_state_reinit      (RsvgState * state);
 G_GNUC_INTERNAL
@@ -205,8 +206,6 @@ void rsvg_state_dominate    (RsvgState * dst, const RsvgState * src);
 G_GNUC_INTERNAL
 void rsvg_state_override    (RsvgState * dst, const RsvgState * src);
 G_GNUC_INTERNAL
-void rsvg_state_finalize    (RsvgState * state);
-G_GNUC_INTERNAL
 void rsvg_state_free_all    (RsvgState * state);
 
 G_GNUC_INTERNAL