"Interior mutability is a design pattern in Rust that allows you to mutate data even when there are immutable references to that data"
> Interior mutability is a design pattern in Rust that allows you to mutate data even when there are immutable references to that data.
in this exercise a Drop checker API has to be created. For this you must define:
In this exercise, you will create a Drop Checker API.
- Two structures:
Define the following structures:
- `Workers` that will have two fields:
- `drops` that will save the number of dropped threads.
- `states` that will save a state of multiple threads.
If the thread is not dropped, the state will be false otherwise true.
- `Thread` that will have the following fields:
- `pid`, the id of the thread.
- `cmd`, the name of the thread.
- `parent`, that will be the link to the structure `Workers` (Tip: this must be a reference to the structure Workers)
- Implementation of each structure:state
- `Workers`: containing:
- `drops`: that will save the number of dropped threads.
- `states`: that will save the state of multiple threads. If the thread is not dropped, the state will be `false`, and will be `true` otherwise.
- `Thread`: containing:
- `pid`: the id of the thread.
- `cmd`: the name of the thread.
- `parent`: a link to the structure `Workers`. (Tip: this should be a reference).
- `Workers` :
You'll need to also add the following associated functions to the structures:
- `new`, that creates a default worker
- `new_worker`, that returns a tuple with the `pid` and a new `Thread`,
this function must receive a `String` being the `cmd`
- `is_dropped`, that receives a `pid` and returns a `bool` that indicates the state of the thread by using the `pid`
- `track_worker`, it should return a `usize`, that will be the last available index of the `states` vector, being the new next thread
- `add_drop`, this function must be **called by the `Drop` trait**. It will receive a `pid` that will be used to change the
state of the thread. If the state of that thread is `true` then it will panic with the message ("Cannot drop {}, because its already dropped", pid).
Otherwise it should change the state to true and increment the `drops` field by one.
- `Workers` :
- `new`: that creates a default worker.
- `new_worker`: that returns a tuple with the `pid` and a new `Thread`. This function must receive a `String` representing the `cmd`.
- `is_dropped`: that receives a `pid` and returns a `bool` that indicates the state of the thread.
- `track_worker`: which returns a `usize` representing the length of the `states` vector. (The index of the next new thread).
- `add_drop`: which is **called by the `Drop` trait**. It will receive a `pid` that will be used to change the state of the thread. If the state of that thread is `true` then it will panic with the message `"Cannot drop X, because its already dropped"`, where `X` represents the `pid`). Otherwise it should change the state to `true` and increment the `drops` field by 1.
- `Thread`:
- `new_thread`, that initializes a new thread
- `skill`, that drops the thread
- `Thread`:
- `new_thread`: that initializes a new thread.
- `skill`: that drops the thread.
- You must implement for the structure `Thread` the `Drop` trait. In this trait you must call the function `add_drop` so that the state of the thread changes
- You must implement the `Drop` trait for the `Thread` structure. In this trait you must call the function `add_drop` so that the state of the thread changes.
davhojt
2 years ago
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