587 lines
16 KiB
Rust
587 lines
16 KiB
Rust
//! A mock type implementing [`Read`] and [`Write`].
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//!
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//! Copied from https://github.com/carllerche/mock-io.
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//!
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//! TODO:
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//! - Either the mock-io crate should be released or this module should be
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//! removed from h2.
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//!
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//! # Overview
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//!
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//! Provides a type that implements [`Read`] + [`Write`] that can be configured
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//! to handle an arbitrary sequence of read and write operations. This is useful
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//! for writing unit tests for networking services as using an actual network
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//! type is fairly non deterministic.
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//!
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//! # Usage
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//!
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//! Add the following to your `Cargo.toml`
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//!
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//! ```toml
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//! [dependencies]
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//! mock-io = { git = "https://github.com/carllerche/mock-io" }
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//! ```
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//!
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//! Then use it in your project. For example, a test could be written:
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//!
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//! ```
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//! extern crate mock_io;
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//!
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//! use mock_io::{Builder, Mock};
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//! use std::io::{Read, Write};
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//!
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//! # /*
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//! #[test]
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//! # */
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//! fn test_io() {
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//! let mut mock = Builder::new()
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//! .write(b"ping")
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//! .read(b"pong")
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//! .build();
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//!
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//! let n = mock.write(b"ping").unwrap();
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//! assert_eq!(n, 4);
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//!
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//! let mut buf = vec![];
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//! mock.read_to_end(&mut buf).unwrap();
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//!
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//! assert_eq!(buf, b"pong");
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//! }
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//! # pub fn main() {
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//! # test_io();
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//! # }
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//! ```
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//!
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//! Attempting to write data that the mock isn't expected will result in a
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//! panic.
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//!
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//! # Tokio
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//!
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//! `Mock` also supports tokio by implementing `AsyncRead` and `AsyncWrite`.
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//! When using `Mock` in context of a Tokio task, it will automatically switch
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//! to "async" behavior (this can also be set explicitly by calling `set_async`
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//! on `Builder`).
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//!
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//! In async mode, calls to read and write are non-blocking and the task using
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//! the mock is notified when the readiness state changes.
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//!
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//! # `io-dump` dump files
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//!
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//! `Mock` can also be configured from an `io-dump` file. By doing this, the
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//! mock value will replay a previously recorded behavior. This is useful for
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//! collecting a scenario from the real world and replying it as part of a test.
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//!
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//! [`Read`]: https://doc.rust-lang.org/std/io/trait.Read.html
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//! [`Write`]: https://doc.rust-lang.org/std/io/trait.Write.html
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#![allow(deprecated)]
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use std::{cmp, io};
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use std::collections::VecDeque;
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use std::time::{Duration, Instant};
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/// An I/O handle that follows a predefined script.
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///
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/// This value is created by `Builder` and implements `Read + `Write`. It
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/// follows the scenario described by the builder and panics otherwise.
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#[derive(Debug)]
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pub struct Mock {
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inner: Inner,
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tokio: tokio::Inner,
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async: Option<bool>,
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}
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#[derive(Debug)]
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pub struct Handle {
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inner: tokio::Handle,
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}
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/// Builds `Mock` instances.
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#[derive(Debug, Clone, Default)]
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pub struct Builder {
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// Sequence of actions for the Mock to take
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actions: VecDeque<Action>,
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// true for Tokio, false for blocking, None to auto detect
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async: Option<bool>,
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}
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#[derive(Debug, Clone)]
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enum Action {
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Read(Vec<u8>),
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Write(Vec<u8>),
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Wait(Duration),
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}
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#[derive(Debug)]
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struct Inner {
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actions: VecDeque<Action>,
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waiting: Option<Instant>,
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}
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impl Builder {
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/// Return a new, empty `Builder.
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pub fn new() -> Self {
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Self::default()
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}
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/// Sequence a `read` operation.
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///
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/// The next operation in the mock's script will be to expect a `read` call
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/// and return `buf`.
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pub fn read(&mut self, buf: &[u8]) -> &mut Self {
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self.actions.push_back(Action::Read(buf.into()));
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self
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}
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/// Sequence a `write` operation.
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///
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/// The next operation in the mock's script will be to expect a `write`
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/// call.
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pub fn write(&mut self, buf: &[u8]) -> &mut Self {
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self.actions.push_back(Action::Write(buf.into()));
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self
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}
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/// Sequence a wait.
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///
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/// The next operation in the mock's script will be to wait without doing so
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/// for `duration` amount of time.
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pub fn wait(&mut self, duration: Duration) -> &mut Self {
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let duration = cmp::max(duration, Duration::from_millis(1));
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self.actions.push_back(Action::Wait(duration));
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self
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}
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/// Build a `Mock` value according to the defined script.
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pub fn build(&mut self) -> Mock {
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let (mock, _) = self.build_with_handle();
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mock
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}
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/// Build a `Mock` value paired with a handle
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pub fn build_with_handle(&mut self) -> (Mock, Handle) {
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let (tokio, handle) = tokio::Inner::new();
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let src = self.clone();
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let mock = Mock {
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inner: Inner {
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actions: src.actions,
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waiting: None,
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},
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tokio: tokio,
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async: src.async,
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};
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let handle = Handle { inner: handle };
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(mock, handle)
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}
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}
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impl Handle {
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/// Sequence a `read` operation.
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///
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/// The next operation in the mock's script will be to expect a `read` call
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/// and return `buf`.
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pub fn read(&mut self, buf: &[u8]) -> &mut Self {
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self.inner.read(buf);
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self
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}
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/// Sequence a `write` operation.
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///
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/// The next operation in the mock's script will be to expect a `write`
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/// call.
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pub fn write(&mut self, buf: &[u8]) -> &mut Self {
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self.inner.write(buf);
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self
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}
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}
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impl Mock {
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fn sync_read(&mut self, dst: &mut [u8]) -> io::Result<usize> {
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use std::thread;
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loop {
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match self.inner.read(dst) {
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Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
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if let Some(rem) = self.inner.remaining_wait() {
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thread::sleep(rem);
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} else {
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// We've entered a dead lock scenario. The peer expects
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// a write but we are reading.
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panic!("mock_io::Mock expects write but currently blocked in read");
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}
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}
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ret => return ret,
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}
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}
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}
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fn sync_write(&mut self, src: &[u8]) -> io::Result<usize> {
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match self.inner.write(src) {
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Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
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panic!("mock_io::Mock not currently expecting a write");
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}
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ret => ret,
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}
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}
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/// Returns `true` if running in a futures-rs task context
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fn is_async(&self) -> bool {
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self.async.unwrap_or(tokio::is_task_ctx())
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}
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}
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impl Inner {
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fn read(&mut self, dst: &mut [u8]) -> io::Result<usize> {
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match self.action() {
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Some(&mut Action::Read(ref mut data)) =>{
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// Figure out how much to copy
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let n = cmp::min(dst.len(), data.len());
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// Copy the data into the `dst` slice
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(&mut dst[..n]).copy_from_slice(&data[..n]);
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// Drain the data from the source
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data.drain(..n);
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// Return the number of bytes read
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Ok(n)
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}
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Some(_) => {
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// Either waiting or expecting a write
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Err(io::ErrorKind::WouldBlock.into())
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}
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None => {
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Ok(0)
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}
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}
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}
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fn write(&mut self, mut src: &[u8]) -> io::Result<usize> {
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let mut ret = 0;
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if self.actions.is_empty() {
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return Err(io::ErrorKind::BrokenPipe.into());
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}
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match self.action() {
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Some(&mut Action::Wait(..)) => {
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return Err(io::ErrorKind::WouldBlock.into());
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}
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_ => {}
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}
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for i in 0..self.actions.len() {
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match self.actions[i] {
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Action::Write(ref mut expect) => {
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let n = cmp::min(src.len(), expect.len());
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assert_eq!(&src[..n], &expect[..n]);
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// Drop data that was matched
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expect.drain(..n);
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src = &src[n..];
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ret += n;
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if src.is_empty() {
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return Ok(ret);
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}
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}
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Action::Wait(..) => {
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break;
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}
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_ => {}
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}
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// TODO: remove write
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}
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Ok(ret)
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}
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fn remaining_wait(&mut self) -> Option<Duration> {
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match self.action() {
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Some(&mut Action::Wait(dur)) => Some(dur),
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_ => None,
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}
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}
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fn action(&mut self) -> Option<&mut Action> {
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loop {
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if self.actions.is_empty() {
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return None;
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}
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match self.actions[0] {
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Action::Read(ref mut data) => {
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if !data.is_empty() {
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break;
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}
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}
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Action::Write(ref mut data) => {
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if !data.is_empty() {
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break;
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}
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}
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Action::Wait(ref mut dur) => {
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if let Some(until) = self.waiting {
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let now = Instant::now();
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if now < until {
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break;
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}
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} else {
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self.waiting = Some(Instant::now() + *dur);
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break;
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}
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}
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}
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let _action = self.actions.pop_front();
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}
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self.actions.front_mut()
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}
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}
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impl io::Read for Mock {
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fn read(&mut self, dst: &mut [u8]) -> io::Result<usize> {
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if self.is_async() {
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tokio::async_read(self, dst)
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} else {
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self.sync_read(dst)
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}
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}
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}
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impl io::Write for Mock {
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fn write(&mut self, src: &[u8]) -> io::Result<usize> {
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if self.is_async() {
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tokio::async_write(self, src)
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} else {
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self.sync_write(src)
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}
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}
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fn flush(&mut self) -> io::Result<()> {
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Ok(())
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}
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}
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// use tokio::*;
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mod tokio {
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extern crate futures;
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extern crate tokio_io;
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extern crate tokio_timer;
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use super::*;
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use self::futures::{Future, Stream, Poll, Async};
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use self::futures::sync::mpsc;
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use self::futures::task::{self, Task};
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use self::tokio_io::{AsyncRead, AsyncWrite};
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use self::tokio_timer::{Timer, Sleep};
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use std::io;
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impl Builder {
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pub fn set_async(&mut self, is_async: bool) -> &mut Self {
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self.async = Some(is_async);
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self
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}
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}
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#[derive(Debug)]
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pub struct Inner {
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timer: Timer,
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sleep: Option<Sleep>,
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read_wait: Option<Task>,
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rx: mpsc::UnboundedReceiver<Action>,
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}
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#[derive(Debug)]
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pub struct Handle {
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tx: mpsc::UnboundedSender<Action>,
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}
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// ===== impl Handle =====
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impl Handle {
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pub fn read(&mut self, buf: &[u8]) {
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mpsc::UnboundedSender::send(&mut self.tx, Action::Read(buf.into())).unwrap();
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}
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pub fn write(&mut self, buf: &[u8]) {
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mpsc::UnboundedSender::send(&mut self.tx, Action::Write(buf.into())).unwrap();
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}
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}
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// ===== impl Inner =====
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impl Inner {
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pub fn new() -> (Inner, Handle) {
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// TODO: We probably want a higher resolution timer.
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let timer = tokio_timer::wheel()
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.tick_duration(Duration::from_millis(1))
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.max_timeout(Duration::from_secs(3600))
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.build();
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let (tx, rx) = mpsc::unbounded();
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let inner = Inner {
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timer: timer,
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sleep: None,
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read_wait: None,
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rx: rx,
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};
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let handle = Handle { tx };
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(inner, handle)
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}
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pub(super) fn poll_action(&mut self) -> Poll<Option<Action>, ()> {
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self.rx.poll()
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}
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}
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impl Mock {
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fn maybe_wakeup_reader(&mut self) {
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match self.inner.action() {
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Some(&mut Action::Read(_)) | None => {
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if let Some(task) = self.tokio.read_wait.take() {
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task.notify();
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}
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}
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_ => {}
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}
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}
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}
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pub fn async_read(me: &mut Mock, dst: &mut [u8]) -> io::Result<usize> {
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loop {
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if let Some(ref mut sleep) = me.tokio.sleep {
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let res = try!(sleep.poll());
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if !res.is_ready() {
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return Err(io::ErrorKind::WouldBlock.into());
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}
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}
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// If a sleep is set, it has already fired
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me.tokio.sleep = None;
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match me.inner.read(dst) {
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Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
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if let Some(rem) = me.inner.remaining_wait() {
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me.tokio.sleep = Some(me.tokio.timer.sleep(rem));
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} else {
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me.tokio.read_wait = Some(task::current());
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return Err(io::ErrorKind::WouldBlock.into());
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}
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}
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Ok(0) => {
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// TODO: Extract
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match me.tokio.poll_action().unwrap() {
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Async::Ready(Some(action)) => {
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me.inner.actions.push_back(action);
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continue;
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}
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Async::Ready(None) => {
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return Ok(0);
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}
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Async::NotReady => {
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return Err(io::ErrorKind::WouldBlock.into());
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}
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}
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}
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ret => return ret,
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}
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}
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}
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pub fn async_write(me: &mut Mock, src: &[u8]) -> io::Result<usize> {
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loop {
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if let Some(ref mut sleep) = me.tokio.sleep {
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let res = try!(sleep.poll());
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if !res.is_ready() {
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return Err(io::ErrorKind::WouldBlock.into());
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}
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}
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// If a sleep is set, it has already fired
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me.tokio.sleep = None;
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match me.inner.write(src) {
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Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
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if let Some(rem) = me.inner.remaining_wait() {
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me.tokio.sleep = Some(me.tokio.timer.sleep(rem));
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} else {
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panic!("unexpected WouldBlock");
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}
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}
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Ok(0) => {
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// TODO: Is this correct?
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if !me.inner.actions.is_empty() {
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return Err(io::ErrorKind::WouldBlock.into());
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}
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// TODO: Extract
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match me.tokio.poll_action().unwrap() {
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Async::Ready(Some(action)) => {
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me.inner.actions.push_back(action);
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continue;
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}
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Async::Ready(None) => {
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panic!("unexpected write");
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}
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Async::NotReady => {
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return Err(io::ErrorKind::WouldBlock.into());
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}
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}
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}
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ret => {
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me.maybe_wakeup_reader();
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return ret;
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}
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}
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}
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}
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impl AsyncRead for Mock {
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}
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impl AsyncWrite for Mock {
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fn shutdown(&mut self) -> Poll<(), io::Error> {
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Ok(Async::Ready(()))
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}
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}
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/// Returns `true` if called from the context of a futures-rs Task
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pub fn is_task_ctx() -> bool {
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use std::panic;
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// Save the existing panic hook
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let h = panic::take_hook();
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// Install a new one that does nothing
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panic::set_hook(Box::new(|_| {}));
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// Attempt to call the fn
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let r = panic::catch_unwind(|| task::current()).is_ok();
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// Re-install the old one
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panic::set_hook(h);
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// Return the result
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r
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}
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}
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