diff --git a/src/rsfilesrc.c b/src/rsfilesrc.c
index 2a272550..b55d85fb 100644
--- a/src/rsfilesrc.c
+++ b/src/rsfilesrc.c
@@ -1,11 +1,17 @@
 #include "rsfilesrc.h"
 
+#include <stdint.h>
+
 /* Declarations for Rust code */
 extern void * filesrc_new (void);
 extern void filesrc_drop (void * filesrc);
-extern int filesrc_fill (void * filesrc);
-extern void filesrc_set_location (void * filesrc, const gchar *location);
-extern gchar * filesrc_get_location (void * filesrc);
+extern GstFlowReturn filesrc_fill (void * filesrc);
+extern void filesrc_set_location (void * filesrc, const char *location);
+extern char * filesrc_get_location (void * filesrc);
+extern uint64_t filesrc_get_size (void * filesrc);
+extern gboolean filesrc_is_seekable (void * filesrc);
+extern gboolean filesrc_start (void * filesrc);
+extern gboolean filesrc_stop (void * filesrc);
 
 GST_DEBUG_CATEGORY_STATIC (gst_rsfile_src_debug);
 #define GST_CAT_DEFAULT gst_rsfile_src_debug
@@ -133,12 +139,7 @@ gst_rsfile_src_fill (GstBaseSrc * basesrc, guint64 offset, guint length,
 {
   GstRsfileSrc *src = GST_RSFILE_SRC (basesrc);
 
-  g_print ("foo %p\n", src->instance);
-  filesrc_fill (src->instance);
-
-  gst_buffer_memset (buf, 0, 0, gst_buffer_get_size (buf));
-
-  return GST_FLOW_OK;
+  return filesrc_fill (src->instance);
 }
 
 static gboolean
@@ -146,7 +147,7 @@ gst_rsfile_src_is_seekable (GstBaseSrc * basesrc)
 {
   GstRsfileSrc *src = GST_RSFILE_SRC (basesrc);
 
-  return TRUE;
+  return filesrc_is_seekable (src->instance);
 }
 
 static gboolean
@@ -154,7 +155,7 @@ gst_rsfile_src_get_size (GstBaseSrc * basesrc, guint64 * size)
 {
   GstRsfileSrc *src = GST_RSFILE_SRC (basesrc);
 
-  *size = -1;
+  *size = filesrc_get_size (src->instance);
 
   return TRUE;
 }
@@ -165,7 +166,7 @@ gst_rsfile_src_start (GstBaseSrc * basesrc)
 {
   GstRsfileSrc *src = GST_RSFILE_SRC (basesrc);
 
-  return TRUE;
+  return filesrc_start (src->instance);
 }
 
 /* unmap and close the rsfile */
@@ -174,7 +175,7 @@ gst_rsfile_src_stop (GstBaseSrc * basesrc)
 {
   GstRsfileSrc *src = GST_RSFILE_SRC (basesrc);
 
-  return TRUE;
+  return filesrc_stop (src->instance);
 }
 
 
diff --git a/src/rsfilesrc.rs b/src/rsfilesrc.rs
index 5e2034fc..81a55447 100644
--- a/src/rsfilesrc.rs
+++ b/src/rsfilesrc.rs
@@ -1,6 +1,40 @@
 use libc::{c_char};
 use std::ffi::{CStr, CString};
 use std::ptr;
+use std::u64;
+
+#[derive(Debug)]
+pub struct FileSrc {
+    location: Option<String>,
+}
+
+#[repr(C)]
+pub enum GstFlowReturn {
+    Ok = 0,
+    NotLinked = -1,
+    Flushing = -2,
+    Eos = -3,
+    NotNegotiated = -4,
+    Error = -5,
+}
+
+#[repr(C)]
+pub enum GBoolean {
+    False = 0,
+    True = 1,
+}
+
+impl FileSrc {
+    fn new() -> FileSrc {
+        FileSrc { location: None }
+    }
+}
+
+impl Drop for FileSrc {
+    fn drop(&mut self) {
+        println!("drop");
+    }
+}
 
 #[no_mangle]
 pub extern "C" fn filesrc_new() -> *mut FileSrc {
@@ -38,25 +72,39 @@ pub extern "C" fn filesrc_get_location(ptr: *mut FileSrc) -> *mut c_char {
 }
 
 #[no_mangle]
-pub extern "C" fn filesrc_fill(ptr: *mut FileSrc) {
+pub extern "C" fn filesrc_fill(ptr: *mut FileSrc) -> GstFlowReturn {
     let filesrc: &mut FileSrc = unsafe { &mut *ptr };
 
-    println!("fill {:?}", filesrc);
+    println!("{:?}", filesrc);
+
+    return GstFlowReturn::Ok;
 }
 
-#[derive(Debug)]
-pub struct FileSrc {
-    location: Option<String>,
+#[no_mangle]
+pub extern "C" fn filesrc_get_size(ptr: *mut FileSrc) -> u64 {
+    let filesrc: &mut FileSrc = unsafe { &mut *ptr };
+
+    return u64::MAX;
 }
 
-impl FileSrc {
-    fn new() -> FileSrc {
-        FileSrc { location: None }
-    }
+#[no_mangle]
+pub extern "C" fn filesrc_start(ptr: *mut FileSrc) -> GBoolean {
+    let filesrc: &mut FileSrc = unsafe { &mut *ptr };
+
+    return GBoolean::True;
 }
 
-impl Drop for FileSrc {
-    fn drop(&mut self) {
-        println!("drop");
-    }
+#[no_mangle]
+pub extern "C" fn filesrc_stop(ptr: *mut FileSrc) -> GBoolean {
+    let filesrc: &mut FileSrc = unsafe { &mut *ptr };
+
+    return GBoolean::True;
 }
+
+#[no_mangle]
+pub extern "C" fn filesrc_is_seekable(ptr: *mut FileSrc) -> GBoolean {
+    let filesrc: &mut FileSrc = unsafe { &mut *ptr };
+
+    return GBoolean::True;
+}
+