Add a Rust struct and store/use it in the C code

src/rsfilesrc.c

@@ -1,5 +1,10 @@
 #include "rsfilesrc.h"
 
+/* Declarations for Rust code */
+extern void * filesrc_new (void);
+extern void filesrc_drop (void * filesrc);
+extern int filesrc_fill (void * filesrc);
+
 GST_DEBUG_CATEGORY_STATIC (gst_rsfile_src_debug);
 #define GST_CAT_DEFAULT gst_rsfile_src_debug
 
@@ -74,6 +79,8 @@ static void
 gst_rsfile_src_init (GstRsfileSrc * src)
 {
   gst_base_src_set_blocksize (GST_BASE_SRC (src), 4096);
+
+  src->instance = filesrc_new ();
 }
 
 static void
@@ -81,6 +88,7 @@ gst_rsfile_src_finalize (GObject * object)
 {
   GstRsfileSrc *src = GST_RSFILE_SRC (object);
 
+  filesrc_drop (src->instance);
   g_free (src->location);
 
   G_OBJECT_CLASS (parent_class)->finalize (object);
@@ -120,15 +128,14 @@ gst_rsfile_src_get_property (GObject * object, guint prop_id, GValue * value,
   }
 }
 
-extern void foo(void);
-
 static GstFlowReturn
 gst_rsfile_src_fill (GstBaseSrc * basesrc, guint64 offset, guint length,
     GstBuffer * buf)
 {
   GstRsfileSrc *src = GST_RSFILE_SRC (basesrc);
 
-  foo();
+  g_print ("foo %p\n", src->instance);
+  filesrc_fill (src->instance);
 
   gst_buffer_memset (buf, 0, 0, gst_buffer_get_size (buf));
 

src/rsfilesrc.h

@@ -25,6 +25,7 @@ struct _GstRsfileSrc {
   GstBaseSrc element;
 
   gchar *location;
+  gpointer instance;
 };
 
 struct _GstRsfileSrcClass {

src/rsfilesrc.rs

@@ -1,4 +1,40 @@
+use std::mem;
+
 #[no_mangle]
-pub extern fn foo() {
-    print!("foo\n");
+pub extern "C" fn filesrc_new() -> *mut FileSrc {
+    let mut instance = Box::new(FileSrc::new());
+    return &mut *instance;
+}
+
+#[no_mangle]
+pub extern "C" fn filesrc_drop(ptr: *mut FileSrc) {
+    let filesrc: &mut FileSrc = unsafe { &mut *ptr };
+
+    println!("drop");
+    drop(filesrc);
+}
+
+#[no_mangle]
+pub extern "C" fn filesrc_fill(ptr: *mut FileSrc) {
+    let filesrc: &mut FileSrc = unsafe { &mut *ptr };
+
+    println!("fill");
+    filesrc.location = Some(String::from("bla"));
+}
+
+#[derive(Debug)]
+pub struct FileSrc {
+    location: Option<String>,
+}
+
+impl FileSrc {
+    fn new() -> FileSrc {
+        FileSrc { location: None }
+    }
+}
+
+impl Drop for FileSrc {
+    fn drop(&mut self) {
+        println!("drop");
+    }
 }