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
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
// This file is part of Gear.

// Copyright (C) 2021-2024 Gear Technologies Inc.
// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0

// This program 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.

// This program 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.

// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.

use crate::{
    async_runtime::{self, signals, Lock, ReplyPoll},
    errors::{Error, Result},
    msg::macros::impl_futures,
    prelude::Vec,
    ActorId, Config, MessageId,
};
use core::{
    future::Future,
    marker::PhantomData,
    pin::Pin,
    task::{Context, Poll},
};
use futures::future::FusedFuture;
use gear_core_errors::ReplyCode;
use scale_info::scale::Decode;

fn poll<F, R>(waiting_reply_to: MessageId, cx: &mut Context<'_>, f: F) -> Poll<Result<R>>
where
    F: Fn(Vec<u8>) -> Result<R>,
{
    let msg_id = crate::msg::id();

    // check if message is timed out.
    if let Some((expected, now)) = async_runtime::locks().is_timeout(msg_id, waiting_reply_to) {
        // Remove lock after timeout.
        async_runtime::locks().remove(msg_id, waiting_reply_to);

        return Poll::Ready(Err(Error::Timeout(expected, now)));
    }

    match signals().poll(waiting_reply_to, cx) {
        ReplyPoll::None => panic!(
            "Somebody created a future with the MessageId that never ended in static replies!"
        ),
        ReplyPoll::Pending => Poll::Pending,
        ReplyPoll::Some((payload, reply_code)) => {
            // Remove lock after waking.
            async_runtime::locks().remove(msg_id, waiting_reply_to);

            match reply_code {
                ReplyCode::Success(_) => Poll::Ready(f(payload)),
                ReplyCode::Error(reason) => {
                    Poll::Ready(Err(Error::ErrorReply(payload.into(), reason)))
                }
                ReplyCode::Unsupported => Poll::Ready(Err(Error::UnsupportedReply(payload))),
            }
        }
    }
}

/// Same as [`MessageFuture`], but allows decoding the reply's payload instead
/// of getting a byte vector.
///
/// Generic `T` type should implement the [`Decode`] trait.
///
/// # Examples
///
/// The following example explicitly annotates variable types for demonstration
/// purposes only. Usually, annotating them is unnecessary because
/// they can be inferred automatically.
///
/// ```
/// use gstd::{
///     msg::{self, CodecMessageFuture},
///     prelude::*,
/// };
/// # use gstd::ActorId;
///
/// #[derive(Decode)]
/// #[codec(crate = gstd::codec)]
/// struct Reply {
///     field: String,
/// }
///
/// #[gstd::async_main]
/// async fn main() {
///     # let dest = ActorId::zero();
///     let future: CodecMessageFuture<Reply> =
///         msg::send_bytes_for_reply_as(dest, b"PING", 0, 0).expect("Unable to send");
///     let reply: Reply = future.await.expect("Unable to get a reply");
///     let field: String = reply.field;
/// }
/// # fn main() {}
/// ```
pub struct CodecMessageFuture<T> {
    /// A message identifier for an expected reply.
    pub waiting_reply_to: MessageId,
    /// Marker
    ///
    /// # Note
    ///
    /// Need to `pub` this field because we are constructing this
    /// field in other files
    pub(crate) _marker: PhantomData<T>,
}

impl_futures!(
    CodecMessageFuture,
    D,
    D,
    |fut, cx| => {
        poll(fut.waiting_reply_to, cx, |reply| {
            D::decode(&mut reply.as_ref()).map_err(Error::Decode)
        })
    }
);

/// Same as [`CreateProgramFuture`], but allows decoding the reply's payload
/// instead of receiving a byte vector.
///
/// Generic `T` type should implement the [`Decode`] trait.
///
/// # Examples
///
/// The following example explicitly annotates variable types for demonstration
/// purposes only. Usually, annotating them is unnecessary because
/// they can be inferred automatically.
///
/// ```
/// use gstd::{msg::CodecCreateProgramFuture, prelude::*, prog, ActorId};
/// # use gstd::CodeId;
///
/// #[derive(Decode)]
/// #[codec(crate = gstd::codec)]
/// struct InitReply {
///     field: String,
/// }
///
/// #[gstd::async_main]
/// async fn main() {
///     # let code_id = CodeId::new([0; 32]);
///     let future: CodecCreateProgramFuture<InitReply> =
///         prog::create_program_bytes_for_reply_as(code_id, b"salt", b"PING", 0, 0)
///             .expect("Unable to create a program");
///     let (prog_id, reply): (ActorId, InitReply) = future.await.expect("Unable to get a reply");
///     let field: String = reply.field;
/// }
/// # fn main() {}
/// ```
pub struct CodecCreateProgramFuture<T> {
    /// A message identifier for an expected reply.
    pub waiting_reply_to: MessageId,
    /// An identifier of a newly created program.
    pub program_id: ActorId,
    /// Marker
    ///
    /// # Note
    ///
    /// Need to `pub` this field because we are constructing this
    /// field in other files.
    pub(crate) _marker: PhantomData<T>,
}

impl_futures!(
    CodecCreateProgramFuture,
    D,
    (ActorId, D),
    |fut, cx| => {
        poll(fut.waiting_reply_to, cx, |reply| {
            D::decode(&mut reply.as_ref())
                .map(|payload| (fut.program_id, payload))
                .map_err(Error::Decode)
        })
    }
);

/// Future returned by async functions related to message sending that wait for
/// a reply (see sending functions with `_for_reply` suffix, e.g.
/// [`send_bytes_for_reply`](super::send_bytes_for_reply)).
///
/// To get the reply payload (in bytes), one should use `.await` syntax. After
/// calling a corresponding async function, the program interrupts its execution
/// until a reply arrives.
///
/// This future keeps the sent message identifier ([`MessageId`] to wake the
/// program after a reply arrives.
///
/// # Examples
///
/// The following example explicitly annotates variable types for demonstration
/// purposes only. Usually, annotating them is unnecessary because
/// they can be inferred automatically.
///
/// ```
/// use gstd::msg::{self, MessageFuture};
/// # use gstd::ActorId;
///
/// #[gstd::async_main]
/// async fn main() {
///     # let dest = ActorId::zero();
///     let future: MessageFuture =
///         msg::send_bytes_for_reply(dest, b"PING", 0, 0).expect("Unable to send");
///     let reply: Vec<u8> = future.await.expect("Unable to get a reply");
/// }
/// # fn main() {}
/// ```
pub struct MessageFuture {
    /// A message identifier for an expected reply.
    ///
    /// This identifier is generated by the corresponding send function (e.g.
    /// [`send_bytes`](super::send_bytes)).
    pub waiting_reply_to: MessageId,
}

impl_futures!(
    MessageFuture,
    Vec<u8>,
    |fut, cx| => {
        poll(fut.waiting_reply_to, cx, Ok)
    }
);

/// Async functions that relate to creating programs wait for a reply from the
/// program's init function. These functions have the suffix` _for_reply`, such
/// as [`crate::prog::create_program_bytes_for_reply`].
///
/// To get the reply payload (in bytes), one should use `.await` syntax. After
/// calling a corresponding async function, the program interrupts its execution
/// until a reply arrives.
///
/// This future keeps the sent message identifier ([`MessageId`]) to wake the
/// program after a reply arrives. Also, it keeps an identifier of a newly
/// created program ([`ActorId`]).
///
/// # Examples
///
/// The following example explicitly annotates variable types for demonstration
/// purposes only. Usually, annotating them is unnecessary because
/// they can be inferred automatically.
///
/// ```
/// use gstd::{msg::CreateProgramFuture, prog, ActorId};
/// # use gstd::CodeId;
///
/// #[gstd::async_main]
/// async fn main() {
///     # let code_id = CodeId::new([0; 32]);
///     let future: CreateProgramFuture =
///         prog::create_program_bytes_for_reply(code_id, b"salt", b"PING", 0, 0)
///             .expect("Unable to create a program");
///     let (prog_id, reply): (ActorId, Vec<u8>) = future.await.expect("Unable to get a reply");
/// }
/// # fn main() {}
/// ```
pub struct CreateProgramFuture {
    /// A message identifier for an expected reply.
    pub waiting_reply_to: MessageId,
    /// An identifier of a newly created program.
    pub program_id: ActorId,
}

impl_futures!(
    CreateProgramFuture,
    (ActorId, Vec<u8>),
    |fut, cx| => {
        poll(fut.waiting_reply_to, cx, |reply| {
            Ok((fut.program_id, reply))
        })
    }
);