redesign: allow borrowing and fix valgrind issues

src/sys/tskbox.rs

@@ -2,18 +2,8 @@ use std::ptr::NonNull;
 
 pub struct TskBox<T> {
     tsk: NonNull<T>,
-    teardown: unsafe extern "C" fn(*mut T) -> i32,
-}
-
-// WIP
-trait TskInit {
-    type Options: Sized;
-    unsafe fn init(tsk: *mut Self, option: Self::Options) -> i32;
-}
-
-// WIP
-trait TskFree {
-    unsafe fn free(tsk: *mut Self);
+    teardown: Option<unsafe extern "C" fn(*mut T) -> i32>,
+    owning: bool,
 }
 
 impl<T> TskBox<T> {
@@ -24,16 +14,33 @@ impl<T> TskBox<T> {
         let x = unsafe { libc::malloc(std::mem::size_of::<T>()) as *mut T };
         let _ = init(x);
         let tsk = NonNull::new(x).unwrap();
-        Self { tsk, teardown }
+        Self {
+            tsk,
+            teardown: Some(teardown),
+            owning: true,
+        }
+    }
+
+    pub fn new_borrowed(owner: &Self) -> Self {
+        let tsk = owner.tsk;
+        Self {
+            tsk,
+            teardown: None,
+            owning: false,
+        }
     }
 }
 
 impl<T> Drop for TskBox<T> {
     fn drop(&mut self) {
-        unsafe {
-            (self.teardown)(self.tsk.as_mut() as *mut T);
+        if let Some(teardown) = self.teardown {
+            unsafe {
+                (teardown)(self.tsk.as_mut() as *mut T);
+            }
+        }
+        if self.owning {
+            unsafe { libc::free(self.tsk.as_ptr() as *mut libc::c_void) }
         }
-        unsafe { libc::free(self.tsk.as_ptr() as *mut libc::c_void) }
     }
 }
 
@@ -56,14 +63,16 @@ fn test_miri() {
 
     let options = 0_i32;
 
-    let _ = TskBox::new(
+    let b = TskBox::new(
         |x: *mut X| unsafe {
             (*x).data = options;
             0
         },
         teardown_x,
     );
 
+    let _ = TskBox::new_borrowed(&b);
+
     //is_send_sync(&b)
 }
 
@@ -77,3 +86,15 @@ fn test_table_collection_tskbox() {
         super::bindings::tsk_table_collection_free,
     );
 }
+
+#[test]
+fn test_table_collection_tskbox_shared_ptr() {
+    let flags: u32 = 0;
+    let tables = TskBox::new(
+        |t: *mut super::bindings::tsk_table_collection_t| unsafe {
+            super::bindings::tsk_table_collection_init(t, flags)
+        },
+        super::bindings::tsk_table_collection_free,
+    );
+    let _ = TskBox::new_borrowed(&tables);
+}