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
/*******************************************************************************
*
* Copyright (c) 2025 - 2026.
* Haixing Hu, Qubit Co. Ltd.
*
* All rights reserved.
*
******************************************************************************/
//! # BiConsumerOnce Types
//!
//! Provides one-time bi-consumer interface implementations for operations
//! accepting two input parameters without returning a result.
//!
//! It is similar to the `FnOnce(&T, &U)` trait in the standard library.
//!
//! This module provides a unified `BiConsumerOnce` trait and one concrete
//! implementation:
//!
//! - **`BoxBiConsumerOnce<T, U>`**: Box-based single ownership
//! implementation
//!
//! # Why No Arc/Rc Variants?
//!
//! Unlike reusable [`BiConsumer`](crate::consumers::BiConsumer)
//! implementations, this module does **not** provide `ArcBiConsumerOnce` or
//! `RcBiConsumerOnce` implementations. This is a design decision based on the
//! fundamental incompatibility between `FnOnce` semantics and shared ownership.
//! See the design documentation for details.
//!
//! # Design Philosophy
//!
//! BiConsumerOnce uses `FnOnce(&T, &U)` semantics: for truly one-time
//! consumption operations.
//!
//! Unlike BiConsumer, BiConsumerOnce consumes itself on first call. Suitable
//! for initialization callbacks, cleanup callbacks, etc.
//!
//! # Author
//!
//! Haixing Hu
use crate::;
// ==========================================================================
// Type Aliases
// ==========================================================================
/// Type alias for bi-consumer once function signature.
type BiConsumerOnceFn<T, U> = dyn FnOnce;
pub use BoxBiConsumerOnce;
pub use FnBiConsumerOnceOps;
pub use BoxConditionalBiConsumerOnce;
// =======================================================================
// 1. BiConsumerOnce Trait - Unified Interface
// =======================================================================
/// BiConsumerOnce trait - Unified one-time bi-consumer interface
///
/// It is similar to the `FnOnce(&T, &U)` trait in the standard library.
///
/// Defines core behavior for all one-time bi-consumer types. Similar to a
/// bi-consumer implementing `FnOnce(&T, &U)`, performs operations
/// accepting two value references but returning no result (side effects
/// only), consuming itself in the process.
///
/// # Automatic Implementations
///
/// - All closures implementing `FnOnce(&T, &U)`
/// - `BoxBiConsumerOnce<T, U>`
///
/// # Features
///
/// - **Unified Interface**: All bi-consumer types share the same `accept`
/// method signature
/// - **Automatic Implementation**: Closures automatically implement this
/// trait with zero overhead
/// - **Type Conversions**: Can convert to BoxBiConsumerOnce
/// - **Generic Programming**: Write functions accepting any one-time
/// bi-consumer type
///
/// # Examples
///
/// ```rust
/// use qubit_function::{BiConsumerOnce, BoxBiConsumerOnce};
/// use std::sync::{Arc, Mutex};
///
/// fn apply_consumer<C: BiConsumerOnce<i32, i32>>(
/// consumer: C,
/// a: &i32,
/// b: &i32
/// ) {
/// consumer.accept(a, b);
/// }
///
/// let log = Arc::new(Mutex::new(Vec::new()));
/// let l = log.clone();
/// let box_con = BoxBiConsumerOnce::new(move |x: &i32, y: &i32| {
/// l.lock().unwrap().push(*x + *y);
/// });
/// apply_consumer(box_con, &5, &3);
/// assert_eq!(*log.lock().unwrap(), vec![8]);
/// ```
///
/// # Author
///
/// Haixing Hu