Trait gcmodule::Trace

pub trait Trace: 'static {
    fn trace(&self, tracer: &mut Tracer) { ... }
    fn is_type_tracked() -> bool
    where
        Self: Sized,
    { ... }
    fn as_any(&self) -> Option<&dyn Any> { ... }
}

Defines how the cycle collector should collect a type.

The 'static bound

Types tracked by the collector can potentially be kept alive forever. Therefore types with non-static references are not allowed.

Provided methods

fn trace(&self, tracer: &mut Tracer)

Define how to visit values referred by this value.

For example, if self.x is a value referred by self, call self.x.trace(tracer) to visit it.

The values that are visited must match the Drop::drop implementation. Otherwise memory leak or panic might happen. After the panic, dereferencing already collected Cc<T> can trigger:

• Undefined behavior on release build.
• Another panic on debug build.

Ideally this can be generated by the compiler, since the compiler already knows how to generate Drop::drop.

fn is_type_tracked() -> bool where
    Self: Sized, 

Whether this type should be tracked by the collector.

Types that might include Cc<T> where T can form a cycle should be tracked. This allows the collector to visit the Cc values from its parents and count references correctly.

If a type T is tracked, Cc<T> will be 3 usize larger and the collector will check them.

For example,

• Vec<u8> is not tracked. It does include any kind of Cc<T>.
• Box<Cc<u8>> is not tracked. It includes Cc<u8> but u8 cannot create cycles.
• Box<dyn Trace> is tracked. The trait object can be anything, including any kinds of types that contains a Cc<T>.

Usually, concrete Rust types can opt-out the cycle collector. There are a few exceptions:

• Trait objects, and types containing trait objects. Trait objects can be anything so they should be tracked.
• Recursive types. Such as, struct S(RefCell<Option<Rc<Box<S>>>>). Those types need an explicit name like S, and a manual implementation of the Trace trait. That implementation should make is_type_tracked return true directly.

This is an optimization for performance. When in-doubt, return true for correctness.

fn as_any(&self) -> Option<&dyn Any>

Provide downcast support.

Types that want downcast support should implement this method like: fn as_any(&self) -> Option<&dyn std::any::Any> { Some(self) }

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Implementations on Foreign Types

impl Trace for bool

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for char

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for f32

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for f64

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for i16

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for i32

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for i64

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for i8

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for isize

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for u16

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for u32

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for u64

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for u8

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for usize

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for ()

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for String

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for &'static str

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: Trace, B: Trace> Trace for (A, B)

fn trace(&self, tracer: &mut Tracer)

fn is_type_tracked() -> bool

fn as_any(&self) -> Option<&dyn Any>

impl<A: Trace, B: Trace, C: Trace> Trace for (A, B, C)

fn trace(&self, tracer: &mut Tracer)

fn is_type_tracked() -> bool

fn as_any(&self) -> Option<&dyn Any>

impl<A: Trace, B: Trace, C: Trace, D: Trace> Trace for (A, B, C, D)

fn trace(&self, tracer: &mut Tracer)

fn is_type_tracked() -> bool

fn as_any(&self) -> Option<&dyn Any>

impl<A: Trace, B: Trace, C: Trace, D: Trace, E: Trace> Trace for (A, B, C, D, E)

fn trace(&self, tracer: &mut Tracer)

fn is_type_tracked() -> bool

fn as_any(&self) -> Option<&dyn Any>

impl<T: Trace> Trace for Box<T>

fn trace(&self, tracer: &mut Tracer)

fn is_type_tracked() -> bool

fn as_any(&self) -> Option<&dyn Any>

impl Trace for Box<dyn Trace>

fn trace(&self, tracer: &mut Tracer)

fn is_type_tracked() -> bool

fn as_any(&self) -> Option<&dyn Any>

impl<T: Copy + Trace> Trace for Cell<T>

fn trace(&self, tracer: &mut Tracer)

fn is_type_tracked() -> bool

fn as_any(&self) -> Option<&dyn Any>

impl<T: Trace> Trace for RefCell<T>

fn trace(&self, tracer: &mut Tracer)

fn is_type_tracked() -> bool

fn as_any(&self) -> Option<&dyn Any>

impl<K: Trace, V: Trace> Trace for BTreeMap<K, V>

fn trace(&self, tracer: &mut Tracer)

fn is_type_tracked() -> bool

fn as_any(&self) -> Option<&dyn Any>

impl<K: Eq + Hash + Trace, V: Trace> Trace for HashMap<K, V>

fn trace(&self, tracer: &mut Tracer)

fn is_type_tracked() -> bool

fn as_any(&self) -> Option<&dyn Any>

impl<T: Trace> Trace for LinkedList<T>

fn trace(&self, tracer: &mut Tracer)

fn is_type_tracked() -> bool

fn as_any(&self) -> Option<&dyn Any>

impl<T: Trace> Trace for VecDeque<T>

fn trace(&self, tracer: &mut Tracer)

fn is_type_tracked() -> bool

fn as_any(&self) -> Option<&dyn Any>

impl<T: Trace> Trace for Vec<T>

fn trace(&self, tracer: &mut Tracer)

fn is_type_tracked() -> bool

fn as_any(&self) -> Option<&dyn Any>

impl<X: 'static> Trace for fn() -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, X: 'static> Trace for fn(_: &A) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, X: 'static> Trace for fn(_: A) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, X: 'static> Trace for fn(_: &A, _: &B) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, X: 'static> Trace for fn(_: A, _: &B) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, X: 'static> Trace for fn(_: &A, _: B) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, X: 'static> Trace for fn(_: A, _: B) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, X: 'static> Trace for fn(_: &A, _: &B, _: &C) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, X: 'static> Trace for fn(_: A, _: &B, _: &C) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, X: 'static> Trace for fn(_: &A, _: B, _: &C) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, X: 'static> Trace for fn(_: A, _: B, _: &C) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, X: 'static> Trace for fn(_: &A, _: &B, _: C) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, X: 'static> Trace for fn(_: A, _: &B, _: C) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, X: 'static> Trace for fn(_: &A, _: B, _: C) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, X: 'static> Trace for fn(_: A, _: B, _: C) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, D: 'static, X: 'static> Trace for fn(_: &A, _: &B, _: &C, _: &D) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, D: 'static, X: 'static> Trace for fn(_: A, _: &B, _: &C, _: &D) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, D: 'static, X: 'static> Trace for fn(_: &A, _: B, _: &C, _: &D) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, D: 'static, X: 'static> Trace for fn(_: A, _: B, _: &C, _: &D) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, D: 'static, X: 'static> Trace for fn(_: &A, _: &B, _: C, _: &D) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, D: 'static, X: 'static> Trace for fn(_: A, _: &B, _: C, _: &D) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, D: 'static, X: 'static> Trace for fn(_: &A, _: B, _: C, _: &D) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, D: 'static, X: 'static> Trace for fn(_: A, _: B, _: C, _: &D) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, D: 'static, X: 'static> Trace for fn(_: &A, _: &B, _: &C, _: D) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, D: 'static, X: 'static> Trace for fn(_: A, _: &B, _: &C, _: D) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, D: 'static, X: 'static> Trace for fn(_: &A, _: B, _: &C, _: D) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, D: 'static, X: 'static> Trace for fn(_: A, _: B, _: &C, _: D) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, D: 'static, X: 'static> Trace for fn(_: &A, _: &B, _: C, _: D) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, D: 'static, X: 'static> Trace for fn(_: A, _: &B, _: C, _: D) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, D: 'static, X: 'static> Trace for fn(_: &A, _: B, _: C, _: D) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, D: 'static, X: 'static> Trace for fn(_: A, _: B, _: C, _: D) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, D: 'static, E: 'static, X: 'static> Trace for fn(_: A, _: B, _: C, _: D, _: E) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<A: 'static, B: 'static, C: 'static, D: 'static, E: 'static, F: 'static, X: 'static> Trace for fn(_: A, _: B, _: C, _: D, _: E, _: F) -> X

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for CString

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for NulError

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for OsString

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for AddrParseError

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for Ipv4Addr

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for Ipv6Addr

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for SocketAddrV4

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for SocketAddrV6

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for TcpListener

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for TcpStream

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for UdpSocket

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<T: Trace> Trace for Option<T>

fn trace(&self, tracer: &mut Tracer)

fn is_type_tracked() -> bool

fn as_any(&self) -> Option<&dyn Any>

impl Trace for PathBuf

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for Child

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for ChildStderr

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for ChildStdin

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for ChildStdout

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for Command

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for ExitStatus

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for Output

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for Stdio

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<T: 'static> Trace for Rc<T>

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<T: 'static> Trace for Weak<T>

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<T: Trace, U: Trace> Trace for Result<T, U>

fn trace(&self, tracer: &mut Tracer)

fn is_type_tracked() -> bool

fn as_any(&self) -> Option<&dyn Any>

impl<T: 'static> Trace for Arc<T>

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<T: 'static> Trace for Mutex<T>

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<T: 'static> Trace for RwLock<T>

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<T: 'static> Trace for JoinHandle<T>

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl<T: 'static> Trace for LocalKey<T>

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

impl Trace for Thread

fn is_type_tracked() -> bool where
    Self: Sized, 

fn as_any(&self) -> Option<&dyn Any>

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Implementors

impl Trace for Cc<dyn Trace>

fn trace(&self, tracer: &mut Tracer)

fn is_type_tracked() -> bool

fn as_any(&self) -> Option<&dyn Any>

impl<T: Trace> Trace for Cc<T>

fn trace(&self, tracer: &mut Tracer)

fn is_type_tracked() -> bool

fn as_any(&self) -> Option<&dyn Any>

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