[librsvg: 2/3] drawing_ctx: move get/remove_acquired_node to rust

[Federico Mena Quintero <federico src gnome org>]

commit 5a59ebe9a3a795e71b508eb81fb573dc5693bda6
Author: Paolo Borelli <pborelli gnome org>
Date:   Thu Jun 14 21:47:37 2018 +0200

    drawing_ctx: move get/remove_acquired_node to rust

 librsvg/rsvg-drawing-ctx.c        | 64 +++------------------------------------
 librsvg/rsvg-drawing-ctx.h        |  8 +++--
 rsvg_internals/src/defs.rs        | 12 ++++++++
 rsvg_internals/src/drawing_ctx.rs | 39 ++++++++++++++++++------
 4 files changed, 51 insertions(+), 72 deletions(-)
---
diff --git a/librsvg/rsvg-drawing-ctx.c b/librsvg/rsvg-drawing-ctx.c
index eda8b82a..89d78445 100644
--- a/librsvg/rsvg-drawing-ctx.c
+++ b/librsvg/rsvg-drawing-ctx.c
@@ -208,7 +208,7 @@ rsvg_drawing_ctx_pop_cr (RsvgDrawingCtx *ctx)
     ctx->cr_stack = g_list_delete_link (ctx->cr_stack, ctx->cr_stack);
 }
 
-static gboolean
+gboolean
 rsvg_drawing_ctx_prepend_acquired_node (RsvgDrawingCtx *ctx,
                                         RsvgNode       *node)
 {
@@ -220,70 +220,16 @@ rsvg_drawing_ctx_prepend_acquired_node (RsvgDrawingCtx *ctx,
     return FALSE;
 }
 
-static void
+void
 rsvg_drawing_ctx_remove_acquired_node (RsvgDrawingCtx *ctx, RsvgNode *node)
 {
     ctx->acquired_nodes = g_slist_remove (ctx->acquired_nodes, node);
 }
 
-/*
- * rsvg_drawing_ctx_acquire_node:
- * @ctx: The drawing context in use
- * @url: The IRI to lookup, or %NULL
- *
- * Use this function when looking up urls to other nodes. This
- * function does proper recursion checking and thereby avoids
- * infinite loops.
- *
- * Nodes acquired by this function must be released using
- * rsvg_drawing_ctx_release_node() in reverse acquiring order.
- *
- * Note that if you acquire a node, you have to release it before trying to
- * acquire it again.  If you acquire a node "#foo" and don't release it before
- * trying to acquire "foo" again, you will obtain a %NULL the second time.
- *
- * Returns: The node referenced by @url; or %NULL if the @url
- *          is %NULL or it does not reference a node.
- */
-RsvgNode *
-rsvg_drawing_ctx_acquire_node (RsvgDrawingCtx *ctx, const char *url)
-{
-  RsvgNode *node;
-
-  if (url == NULL)
-      return NULL;
-
-  node = rsvg_defs_lookup (ctx->defs, url);
-  if (node == NULL)
-    return NULL;
-
-  if (rsvg_drawing_ctx_prepend_acquired_node (ctx, node)) {
-    return node;
-  }
-
-  return NULL;
-}
-
-/*
- * rsvg_drawing_ctx_release_node:
- * @ctx: The drawing context the node was acquired from
- * @node: Node to release
- *
- * Releases a node previously acquired via rsvg_drawing_ctx_acquire_node() or
- * rsvg_drawing_ctx_acquire_node_of_type().
- *
- * if @node is %NULL, this function does nothing.
- */
-void
-rsvg_drawing_ctx_release_node (RsvgDrawingCtx *ctx, RsvgNode *node)
+RsvgDefs *
+rsvg_drawing_ctx_get_defs (RsvgDrawingCtx *ctx)
 {
-  if (node == NULL)
-    return;
-
-  g_return_if_fail (ctx->acquired_nodes != NULL);
-  g_return_if_fail (ctx->acquired_nodes->data == node);
-
-  rsvg_drawing_ctx_remove_acquired_node (ctx, node);
+    return ctx->defs;
 }
 
 void
diff --git a/librsvg/rsvg-drawing-ctx.h b/librsvg/rsvg-drawing-ctx.h
index ed824215..f6142cdd 100644
--- a/librsvg/rsvg-drawing-ctx.h
+++ b/librsvg/rsvg-drawing-ctx.h
@@ -81,11 +81,13 @@ G_GNUC_INTERNAL
 gboolean rsvg_drawing_ctx_is_cairo_context_nested (RsvgDrawingCtx *ctx, cairo_t *cr);
 
 G_GNUC_INTERNAL
-RsvgNode *rsvg_drawing_ctx_acquire_node         (RsvgDrawingCtx * ctx, const char *url);
+gboolean rsvg_drawing_ctx_prepend_acquired_node (RsvgDrawingCtx *ctx, RsvgNode *node);
+
 G_GNUC_INTERNAL
-RsvgNode *rsvg_drawing_ctx_acquire_node_of_type (RsvgDrawingCtx * ctx, const char *url, RsvgNodeType type);
+void rsvg_drawing_ctx_remove_acquired_node (RsvgDrawingCtx *ctx, RsvgNode *node);
+
 G_GNUC_INTERNAL
-void rsvg_drawing_ctx_release_node              (RsvgDrawingCtx * ctx, RsvgNode *node);
+RsvgDefs *rsvg_drawing_ctx_get_defs (RsvgDrawingCtx *ctx);
 
 G_GNUC_INTERNAL
 void rsvg_drawing_ctx_add_node_and_ancestors_to_stack (RsvgDrawingCtx *draw_ctx, RsvgNode *node);
diff --git a/rsvg_internals/src/defs.rs b/rsvg_internals/src/defs.rs
index 94c23662..6f9ddce3 100644
--- a/rsvg_internals/src/defs.rs
+++ b/rsvg_internals/src/defs.rs
@@ -12,6 +12,7 @@ extern "C" {
         id: *const libc::c_char,
         node: *const RsvgNode,
     );
+    fn rsvg_defs_lookup(defs: *const RsvgDefs, name: *const libc::c_char) -> *mut RsvgNode;
 }
 
 pub fn register_node_by_id(defs: *mut RsvgDefs, id: &str, node: &RsvgNode) {
@@ -19,3 +20,14 @@ pub fn register_node_by_id(defs: *mut RsvgDefs, id: &str, node: &RsvgNode) {
         rsvg_defs_register_node_by_id(defs, id.to_glib_none().0, node);
     }
 }
+
+pub fn lookup(defs: *const RsvgDefs, name: &str) -> Option<&mut RsvgNode> {
+    unsafe {
+        let node = rsvg_defs_lookup(defs, name.to_glib_none().0);
+        if node.is_null() {
+            None
+        } else {
+            Some(&mut *node)
+        }
+    }
+}
diff --git a/rsvg_internals/src/drawing_ctx.rs b/rsvg_internals/src/drawing_ctx.rs
index 4faf4756..fafb2eba 100644
--- a/rsvg_internals/src/drawing_ctx.rs
+++ b/rsvg_internals/src/drawing_ctx.rs
@@ -12,6 +12,7 @@ use pangocairo;
 use bbox::{BoundingBox, RsvgBbox};
 use clip_path::{ClipPathUnits, NodeClipPath};
 use coord_units::CoordUnits;
+use defs::{self, RsvgDefs};
 use filters::filter_render;
 use iri::IRI;
 use mask::NodeMask;
@@ -49,12 +50,14 @@ extern "C" {
 
     fn rsvg_drawing_ctx_pop_view_box(draw_ctx: *const RsvgDrawingCtx);
 
-    fn rsvg_drawing_ctx_acquire_node(
+    fn rsvg_drawing_ctx_prepend_acquired_node(
         draw_ctx: *const RsvgDrawingCtx,
-        url: *const libc::c_char,
-    ) -> *mut RsvgNode;
+        node: *mut RsvgNode,
+    ) -> glib_sys::gboolean;
+
+    fn rsvg_drawing_ctx_remove_acquired_node(draw_ctx: *const RsvgDrawingCtx, node: *mut RsvgNode);
 
-    fn rsvg_drawing_ctx_release_node(draw_ctx: *const RsvgDrawingCtx, node: *mut RsvgNode);
+    fn rsvg_drawing_ctx_get_defs(draw_ctx: *const RsvgDrawingCtx) -> *const RsvgDefs;
 
     fn rsvg_drawing_ctx_get_offset(
         draw_ctx: *const RsvgDrawingCtx,
@@ -144,14 +147,30 @@ pub fn pop_view_box(draw_ctx: *const RsvgDrawingCtx) {
     }
 }
 
+// Use this function when looking up urls to other nodes. This function
+// does proper recursion checking and thereby avoids infinite loops.
+//
+// Nodes acquired by this function must be released in reverse
+// acquiring order.
+//
+// Note that if you acquire a node, you have to release it before trying to
+// acquire it again.  If you acquire a node "#foo" and don't release it before
+// trying to acquire "foo" again, you will obtain a %NULL the second time.
 pub fn get_acquired_node(draw_ctx: *const RsvgDrawingCtx, url: &str) -> Option<AcquiredNode> {
-    let raw_node = unsafe { rsvg_drawing_ctx_acquire_node(draw_ctx, str::to_glib_none(url).0) };
+    let defs = unsafe {
+        let d = rsvg_drawing_ctx_get_defs(draw_ctx);
+        &*d
+    };
 
-    if raw_node.is_null() {
-        None
-    } else {
-        Some(AcquiredNode(draw_ctx, raw_node))
+    if let Some(node) = defs::lookup(defs, url) {
+        unsafe {
+            if from_glib(rsvg_drawing_ctx_prepend_acquired_node(draw_ctx, node)) {
+                return Some(AcquiredNode(draw_ctx, node));
+            }
+        }
     }
+
+    None
 }
 
 // Use this function when looking up urls to other nodes, and when you expect
@@ -646,7 +665,7 @@ pub struct AcquiredNode(*const RsvgDrawingCtx, *mut RsvgNode);
 impl Drop for AcquiredNode {
     fn drop(&mut self) {
         unsafe {
-            rsvg_drawing_ctx_release_node(self.0, self.1);
+            rsvg_drawing_ctx_remove_acquired_node(self.0, self.1);
         }
     }
 }