1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162

// Copyright 2023 Centrifuge Foundation (centrifuge.io).
//
// This file is part of the Centrifuge chain project.
// Centrifuge is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version (see http://www.gnu.org/licenses).
// Centrifuge is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
#![cfg_attr(not(feature = "std"), no_std)]

use frame_support::{
	dispatch::GetDispatchInfo,
	pallet_prelude::*,
	traits::{IsSubType, OriginTrait},
	BoundedVec,
};
use frame_system::pallet_prelude::*;
pub use pallet::*;
use sp_runtime::traits::Dispatchable;
use sp_std::boxed::Box;
pub use weights::WeightInfo;

#[cfg(feature = "runtime-benchmarks")]
mod benchmarking;

#[cfg(test)]
mod mock;
#[cfg(test)]
mod tests;

mod weights;

#[frame_support::pallet]
pub mod pallet {
	use super::*;

	#[pallet::config]
	pub trait Config: frame_system::Config {
		type RuntimeEvent: From<Event<Self>> + IsType<<Self as frame_system::Config>::RuntimeEvent>;

		/// The handler used to check remarks before and after call dispatch.
		type RemarkDispatchHandler: RemarkDispatchHandler<RemarkArgs<Self>>;

		/// The overarching call type.
		type RuntimeCall: Parameter
			+ Dispatchable<RuntimeOrigin = Self::RuntimeOrigin>
			+ GetDispatchInfo
			+ From<frame_system::Call<Self>>
			+ IsSubType<Call<Self>>
			+ IsType<<Self as frame_system::Config>::RuntimeCall>;

		/// Weight information.
		type WeightInfo: WeightInfo;

		/// The type attached to the remark event.
		type Remark: Parameter + Member + Default;

		/// Type that restrains the maximum remarks that can be attached to a
		/// call.
		type MaxRemarksPerCall: Get<u32>;
	}

	#[pallet::pallet]
	pub struct Pallet<T>(_);

	#[pallet::event]
	#[pallet::generate_deposit(pub (super) fn deposit_event)]
	pub enum Event<T: Config> {
		/// A remark was made.
		Remark {
			remarks: BoundedVec<T::Remark, T::MaxRemarksPerCall>,
			call: <T as Config>::RuntimeCall,
		},
	}

	#[pallet::error]
	pub enum Error<T> {
		/// No remarks were provided.
		NoRemarks,
	}

	#[pallet::call]
	impl<T: Config> Pallet<T> {
		/// Add remarks to a call.
		///
		/// The weight calculation is similar to the one in the Proxy.proxy.
		#[pallet::call_index(0)]
		#[pallet::weight({
			let dispatch_info = call.get_dispatch_info();
			(T::WeightInfo::remark(T::MaxRemarksPerCall::get())
				.saturating_add(dispatch_info.weight),
			dispatch_info.class)
		})]
		pub fn remark(
			origin: OriginFor<T>,
			remarks: BoundedVec<T::Remark, T::MaxRemarksPerCall>,
			call: Box<<T as Config>::RuntimeCall>,
		) -> DispatchResult {
			ensure!(!remarks.is_empty(), Error::<T>::NoRemarks);

			T::RemarkDispatchHandler::pre_dispatch_check((
				origin.clone(),
				remarks.clone(),
				call.clone(),
			))?;

			let mut filtered_origin = origin.clone();

			// Nested remark calls are not allowed.
			filtered_origin.add_filter(move |c: &<T as frame_system::Config>::RuntimeCall| {
				let c = <T as Config>::RuntimeCall::from_ref(c);
				!matches!(c.is_sub_type(), Some(Call::remark { .. }))
			});

			call.clone()
				.dispatch(filtered_origin)
				.map(|_| ())
				.map_err(|e| e.error)?;

			T::RemarkDispatchHandler::post_dispatch_check((origin, remarks.clone(), call.clone()))?;

			Self::deposit_event(Event::Remark {
				remarks,
				call: *call,
			});

			Ok(())
		}
	}
}

/// The type used in the RemarkDispatchHandler trait of the pallet's Config.
pub type RemarkArgs<T> = (
	OriginFor<T>,
	BoundedVec<<T as Config>::Remark, <T as Config>::MaxRemarksPerCall>,
	Box<<T as Config>::RuntimeCall>,
);

/// The handler used to check remarks before and after call dispatch.
pub trait RemarkDispatchHandler<T> {
	fn pre_dispatch_check(t: T) -> DispatchResult;

	fn post_dispatch_check(t: T) -> DispatchResult;
}

pub struct NoopRemarkDispatchHandler<T>(PhantomData<T>);

impl<T> RemarkDispatchHandler<RemarkArgs<T>> for NoopRemarkDispatchHandler<T>
where
	T: Config,
{
	fn pre_dispatch_check(_t: RemarkArgs<T>) -> DispatchResult {
		Ok(())
	}

	fn post_dispatch_check(_t: RemarkArgs<T>) -> DispatchResult {
		Ok(())
	}
}