futuresdr 0.0.41

An Experimental Async SDR Runtime for Heterogeneous Architectures.
Documentation 
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

use std::future::Future;
use std::pin::Pin;

use crate::runtime::Result;
use crate::runtime::dev::BlockMeta;
use crate::runtime::dev::MessageOutputs;
use crate::runtime::dev::WorkIo;

/// Send-capable marker for normal runtime blocks.
///
/// This keeps verbose return-type-notation bounds in one place: normal blocks
/// must have a `Send` value, `Send` block-on future, and `Send` futures returned
/// from the kernel lifecycle methods.
#[doc(hidden)]
pub trait SendKernel: Kernel<BlockOn: Send> + Send
where
    Self: Kernel<work(..): Send, init(..): Send, deinit(..): Send>,
{
}

impl<T> SendKernel for T where
    T: Kernel<BlockOn: Send, work(..): Send, init(..): Send, deinit(..): Send> + Send
{
}

/// Processing logic for a block.
///
/// `Kernel` is the central trait custom block authors implement. The
/// `#[derive(Block)]` macro declares stream and message ports from annotated
/// fields and methods; the `Kernel` implementation supplies initialization,
/// work, and shutdown behavior.
///
/// The runtime calls [`Kernel::init`] once, then repeatedly calls
/// [`Kernel::work`] until the block marks itself finished or the flowgraph is
/// stopped, and finally calls [`Kernel::deinit`]. A `work()` implementation
/// should consume and produce exactly the number of stream items it handled and
/// use [`WorkIo`] to request another immediate call, wait on a future, or finish.
///
/// Normal runtime entry points accept only kernels whose value, block-on future,
/// and returned futures are `Send`. Kernels that do not satisfy these bounds can
/// still run in a local domain.
///
/// ```
/// use futuresdr::runtime::dev::prelude::*;
///
/// #[derive(Block)]
/// struct Scale {
///     #[input]
///     input: DefaultCpuReader<f32>,
///     #[output]
///     output: DefaultCpuWriter<f32>,
///     gain: f32,
/// }
///
/// impl Kernel for Scale {
///     async fn work(
///         &mut self,
///         io: &mut WorkIo,
///         _mo: &mut MessageOutputs,
///         _meta: &mut BlockMeta,
///     ) -> Result<()> {
///         let input = self.input.slice();
///         let output = self.output.slice();
///         let n = input.len().min(output.len());
///
///         for i in 0..n {
///             output[i] = input[i] * self.gain;
///         }
///
///         self.input.consume(n);
///         self.output.produce(n);
///
///         if self.input.finished() {
///             io.finished = true;
///         }
///
///         Ok(())
///     }
/// }
/// ```
pub trait Kernel {
    /// Typed future that may be used to wake the block again.
    type BlockOn: Future<Output = ()> + 'static = std::future::Pending<()>;

    /// Return the typed future that should wake this block again.
    ///
    /// This is queried after [`WorkIo::block_on`] has been set. Returning
    /// `None` falls back to waiting only for inbox/stream notifications.
    fn block_on(&mut self) -> Option<Pin<&mut Self::BlockOn>> {
        None
    }

    /// Process stream data and emit messages.
    ///
    /// Implementations inspect their input buffers, write output buffers, update
    /// consume/produce counts, optionally post PMTs through [`MessageOutputs`],
    /// and update [`WorkIo`] flags before returning.
    fn work(
        &mut self,
        _io: &mut WorkIo,
        _mo: &mut MessageOutputs,
        _b: &mut BlockMeta,
    ) -> impl Future<Output = Result<()>> {
        async { Ok(()) }
    }

    /// Initialize the kernel before normal work starts.
    ///
    /// This is the place to allocate runtime resources, send initial messages,
    /// or update [`BlockMeta`]. Stream ports have already been initialized and
    /// validated when this method is called.
    fn init(
        &mut self,
        _mo: &mut MessageOutputs,
        _b: &mut BlockMeta,
    ) -> impl Future<Output = Result<()>> {
        async { Ok(()) }
    }

    /// De-initialize the kernel after work has stopped.
    ///
    /// This is called during block shutdown even when the block stopped because
    /// the flowgraph was terminated. It should release resources owned by the
    /// block and may post final messages.
    fn deinit(
        &mut self,
        _mo: &mut MessageOutputs,
        _b: &mut BlockMeta,
    ) -> impl Future<Output = Result<()>> {
        async { Ok(()) }
    }
}