vendor/criterion/src/async_executor.rs

   1 //! This module defines a trait that can be used to plug in different Futures executors into
   2 //! Criterion.rs' async benchmarking support.
   3 //!
   4 //! Implementations are provided for:
   5 //! * Tokio (implemented directly for tokio::Runtime)
   6 //! * Async-std
   7 //! * Smol
   8 //! * The Futures crate
   9 //!
  10 //! Please note that async benchmarks will have a small amount of measurement overhead relative
  11 //! to synchronous benchmarks. It is recommended to use synchronous benchmarks where possible, to
  12 //! improve measurement accuracy.
  13
  14 use std::future::Future;
  15
  16 /// Plugin trait used to allow benchmarking on multiple different async runtimes.
  17 ///
  18 /// Smol, Tokio and Async-std are supported out of the box, as is the current-thread runner from the
  19 /// Futures crate; it is recommended to use whichever runtime you use in production.
  20 pub trait AsyncExecutor {
  21     /// Spawn the given future onto this runtime and block until it's complete, returning the result.
  22     fn block_on<T>(&self, future: impl Future<Output = T>) -> T;
  23 }
  24
  25 /// Runs futures on the 'futures' crate's built-in current-thread executor
  26 #[cfg(feature = "async_futures")]
  27 pub struct FuturesExecutor;
  28 #[cfg(feature = "async_futures")]
  29 impl AsyncExecutor for FuturesExecutor {
  30     fn block_on<T>(&self, future: impl Future<Output = T>) -> T {
  31         futures::executor::block_on(future)
  32     }
  33 }
  34
  35 /// Runs futures on the 'smol' crate's global executor
  36 #[cfg(feature = "async_smol")]
  37 pub struct SmolExecutor;
  38 #[cfg(feature = "async_smol")]
  39 impl AsyncExecutor for SmolExecutor {
  40     fn block_on<T>(&self, future: impl Future<Output = T>) -> T {
  41         smol::block_on(future)
  42     }
  43 }
  44
  45 #[cfg(feature = "async_tokio")]
  46 impl AsyncExecutor for tokio::runtime::Runtime {
  47     fn block_on<T>(&self, future: impl Future<Output = T>) -> T {
  48         self.block_on(future)
  49     }
  50 }
  51 #[cfg(feature = "async_tokio")]
  52 impl AsyncExecutor for &tokio::runtime::Runtime {
  53     fn block_on<T>(&self, future: impl Future<Output = T>) -> T {
  54         (*self).block_on(future)
  55     }
  56 }
  57
  58 /// Runs futures on the 'async-std' crate's global executor
  59 #[cfg(feature = "async_std")]
  60 pub struct AsyncStdExecutor;
  61 #[cfg(feature = "async_std")]
  62 impl AsyncExecutor for AsyncStdExecutor {
  63     fn block_on<T>(&self, future: impl Future<Output = T>) -> T {
  64         async_std::task::block_on(future)
  65     }
  66 }