Module egui::any [−][src]
Expand description
Any-type storages for Memory.
This module contains structs to store arbitrary types using Any trait. Also, they can be cloned, and structs in [serializable] can be de/serialized.
All this is just HashMap<TypeId, Box<dyn Any + static>> and HashMap<Key, Box<dyn Any + static>>, but with helper functions and hacks for cloning and de/serialization.
Trait requirements
If you want to store your type here, it must implement Clone and Any and be 'static, which means it must not contain references. If you want to store your data in serializable storage, it must implement serde::Serialize and serde::Deserialize under the persistent feature.
TypeMap
It stores everything by just type. You should use this map for your widget when all instances of your widgets can have only one state. E.g. for popup windows, for color picker.
To not have intersections, you should create newtype for anything you try to store here, like:
struct MyEditBool(pub bool);
AnyMap<Key>
TypeMap and AnyMap<Key> has a quite similar interface, except for AnyMap you should pass Key to get and insert things.
It stores everything by Key, this should be used when your widget can have different data for different instances of the widget.
serializable
TypeMap and [serializable::TypeMap] has exactly the same interface, but [serializable::TypeMap] only requires serde traits for stored object under persistent feature. Same thing for AnyMap and [serializable::AnyMap].
What could break
Things here could break only when you trying to load this from file.
First, serialized TypeId in [serializable::TypeMap] could broke if you updated the version of the Rust compiler between runs.
Second, count and reset all instances of a type in [serializable::AnyMap] could return an incorrect value for the same reason.
Deserialization errors of loaded elements of these storages can be determined only when you call get_... functions, they not logged and not provided to a user, on this errors value is just replaced with or_insert()/default value.
When not to use this
This is not for important widget data. Some errors are just ignored and the correct value of type is inserted when you call. This is done to more simple interface.
You shouldn’t use any map here when you need very reliable state storage with rich error-handling. For this purpose you should create your own Memory struct and pass it everywhere you need it. Then, you should de/serialize it by yourself, handling all serialization or other errors as you wish.