Module observe 

Types and traits for observing mutations to data structures.

How Observers Work

Observers are types that implement DerefMut to the target type being observed. When any method requiring &mut self is called, it triggers the DerefMut hook where change tracking occurs. Additionally, for specific methods like String::push_str and Vec::push, observers provide specialized implementations for more precise tracking.

For types that already implement Deref (like Box<T>), implementing observers is more challenging. If type A dereferences to B, and we have corresponding observers A' and B', where should A' deref to?

• If A' → A → B: Changes on B cannot be precisely tracked (because no B' in the dereference chain)
• If A' → B' → B: Properties and methods on A become inaccessible (because no A in the dereference chain)

To solve this, we use a Pointer type to create the dereference chain: A' → B' → Pointer<A> → A → B. This allows tracking changes on both A and B.

Structs

DefaultSpec

Default observation specification.

SnapshotSpec

Snapshot-based observation specification.

Traits

Observe

A trait for types that can be observed for mutations.

ObserveExt

Extension trait providing ergonomic methods for types implementing Observe.

Observer

A trait for observer types that wrap and track mutations to values.

RefObserve

A trait for types whose references can be observed for mutations.

SerializeObserver

Trait for observers that can serialize their recorded mutations.

SerializeObserverExt

Extension trait providing ergonomic methods for SerializeObserver.