bendns' repos / rust-fsm
Finite state machines in rust; bendns fork to add types.
Implement a DSL compiler for defining state machines based on `rust-fsm` and add examples.
Browse Source
Yevhenii Babichenko 2019-04-29
parent 9780937 · commit 5c33ea7
Diffstat
-rw-r--r--rust_fsm/Cargo.toml3
-rw-r--r--rust_fsm/examples/circuit_breaker_dsl.rs59
-rw-r--r--rust_fsm/examples/simple.rs23
-rw-r--r--rust_fsm/src/lib.rs2
-rw-r--r--rust_fsm_dsl/Cargo.toml4
-rw-r--r--rust_fsm_dsl/src/lib.rs177
6 files changed, 263 insertions, 5 deletions
diff --git a/rust_fsm/Cargo.toml b/rust_fsm/Cargo.toml
index 09d6a83..486cf51 100644
--- a/rust_fsm/Cargo.toml
+++ b/rust_fsm/Cargo.toml
@@ -11,4 +11,5 @@ version = "0.1.0"
authors = ["Yevhenii Babichenko"]
edition = "2018"
-[dependencies]
+[dev-dependencies]
+rust-fsm-dsl = { path = "../rust_fsm_dsl" }
diff --git a/rust_fsm/examples/circuit_breaker_dsl.rs b/rust_fsm/examples/circuit_breaker_dsl.rs
new file mode 100644
index 0000000..6a22aab
--- /dev/null
+++ b/rust_fsm/examples/circuit_breaker_dsl.rs
@@ -0,0 +1,59 @@
+/// A dummy implementation of the Circuit Breaker pattern to demonstrate
+/// capabilities of its library DSL for defining finite state machines.
+/// https://martinfowler.com/bliki/CircuitBreaker.html
+#[macro_use]
+extern crate rust_fsm_dsl;
+
+use rust_fsm::*;
+use std::sync::{Arc, Mutex};
+
+state_machine! {
+ CircuitBreaker(Closed)
+
+ Closed(Unsuccessful) => Open [SetupTimer],
+ Open(TimerTriggered) => HalfOpen,
+ HalfOpen(Successful) => Closed,
+ HalfOpen(Unsuccessful) => Open [SetupTimer],
+}
+
+fn main() {
+ let machine: StateMachineWrapper<CircuitBreaker> = StateMachineWrapper::new();
+
+ // Unsuccessful request
+ let machine = Arc::new(Mutex::new(machine));
+ {
+ let mut lock = machine.lock().unwrap();
+ let res = lock.consume_anyway(&CircuitBreakerInput::Unsuccessful);
+ assert_eq!(res, Some(CircuitBreakerOutput::SetupTimer));
+ assert_eq!(lock.state(), &CircuitBreakerState::Open);
+ }
+
+ // Set up a timer
+ let machine_wait = machine.clone();
+ std::thread::spawn(move || {
+ std::thread::sleep_ms(5000);
+ let mut lock = machine_wait.lock().unwrap();
+ let res = lock.consume_anyway(&CircuitBreakerInput::TimerTriggered);
+ assert_eq!(res, None);
+ assert_eq!(lock.state(), &CircuitBreakerState::HalfOpen);
+ });
+
+ // Try to pass a request when the circuit breaker is still open
+ let machine_try = machine.clone();
+ std::thread::spawn(move || {
+ std::thread::sleep_ms(1000);
+ let mut lock = machine_try.lock().unwrap();
+ let res = lock.consume_anyway(&CircuitBreakerInput::Successful);
+ assert_eq!(res, None);
+ assert_eq!(lock.state(), &CircuitBreakerState::Open);
+ });
+
+ // Test if the circit breaker was actually closed
+ std::thread::sleep_ms(7000);
+ {
+ let mut lock = machine.lock().unwrap();
+ let res = lock.consume_anyway(&CircuitBreakerInput::Successful);
+ assert_eq!(res, None);
+ assert_eq!(lock.state(), &CircuitBreakerState::Closed);
+ }
+}
diff --git a/rust_fsm/examples/simple.rs b/rust_fsm/examples/simple.rs
new file mode 100644
index 0000000..46ef7be
--- /dev/null
+++ b/rust_fsm/examples/simple.rs
@@ -0,0 +1,23 @@
+#[macro_use]
+extern crate rust_fsm_dsl;
+
+use rust_fsm::*;
+
+state_machine! {
+ Door(Open)
+
+ Open(Key) => Closed,
+ Closed(Key) => Open,
+ Open(Break) => Broken,
+ Closed(Break) => Broken,
+}
+
+fn main() {
+ let mut machine: StateMachineWrapper<Door> = StateMachineWrapper::new();
+ machine.consume(&DoorInput::Key).unwrap();
+ println!("{:?}", machine.state());
+ machine.consume(&DoorInput::Key).unwrap();
+ println!("{:?}", machine.state());
+ machine.consume(&DoorInput::Break).unwrap();
+ println!("{:?}", machine.state());
+}
diff --git a/rust_fsm/src/lib.rs b/rust_fsm/src/lib.rs
index 259e038..7c5fbd2 100644
--- a/rust_fsm/src/lib.rs
+++ b/rust_fsm/src/lib.rs
@@ -30,7 +30,7 @@
//! All you need to do to build a state machine is to implement the
//! `StateMachine` trait and use it in conjuctions with some of the provided
//! wrappers (for now there is only `StateMachineWrapper`).
-//!
+//!
//! You can see an example of the Circuit Breaker state machine in the
//! [project repository][repo].
//!
diff --git a/rust_fsm_dsl/Cargo.toml b/rust_fsm_dsl/Cargo.toml
index e85b73d..6b8a2a5 100644
--- a/rust_fsm_dsl/Cargo.toml
+++ b/rust_fsm_dsl/Cargo.toml
@@ -16,6 +16,4 @@ proc-macro = true
[dependencies]
syn = "*"
-
-[dev-dependencies]
-rust-fsm = { path = "../rust_fsm" }
+quote = "*"
diff --git a/rust_fsm_dsl/src/lib.rs b/rust_fsm_dsl/src/lib.rs
index e69de29..479e119 100644
--- a/rust_fsm_dsl/src/lib.rs
+++ b/rust_fsm_dsl/src/lib.rs
@@ -0,0 +1,177 @@
+#![recursion_limit = "128"]
+extern crate proc_macro;
+
+use proc_macro::TokenStream;
+use quote::quote;
+use std::collections::HashSet;
+use syn::{
+ bracketed, parenthesized,
+ parse::{Parse, ParseStream, Result},
+ parse_macro_input,
+ punctuated::Punctuated,
+ token::Bracket,
+ Ident, Token,
+};
+
+struct TransitionDef {
+ initial_state: Ident,
+ input_value: Ident,
+ final_state: Ident,
+ output: Option<Ident>,
+}
+
+impl Parse for TransitionDef {
+ fn parse(input: ParseStream) -> Result<Self> {
+ let initial_state = input.parse()?;
+ let input_content;
+ parenthesized!(input_content in input);
+ let input_value = input_content.parse()?;
+ input.parse::<Token![=>]>()?;
+ let final_state = input.parse()?;
+ let output = if input.lookahead1().peek(Bracket) {
+ let output_content;
+ bracketed!(output_content in input);
+ Some(output_content.parse()?)
+ } else {
+ None
+ };
+ Ok(Self {
+ initial_state,
+ input_value,
+ final_state,
+ output,
+ })
+ }
+}
+
+struct StateMachineDef {
+ name: Ident,
+ initial_state: Ident,
+ transitions: Punctuated<TransitionDef, Token![,]>,
+}
+
+impl Parse for StateMachineDef {
+ fn parse(input: ParseStream) -> Result<Self> {
+ let name = input.parse()?;
+ let initial_state_content;
+ parenthesized!(initial_state_content in input);
+ let initial_state = initial_state_content.parse()?;
+ let transitions = input.parse_terminated(TransitionDef::parse)?;
+ Ok(Self {
+ name,
+ initial_state,
+ transitions,
+ })
+ }
+}
+
+#[proc_macro]
+pub fn state_machine(tokens: TokenStream) -> TokenStream {
+ let input = parse_macro_input!(tokens as StateMachineDef);
+
+ let struct_name = input.name;
+
+ let mut states = HashSet::new();
+ let mut inputs = HashSet::new();
+ let mut outputs = HashSet::new();
+
+ states.insert(&input.initial_state);
+
+ for transition in input.transitions.iter() {
+ states.insert(&transition.initial_state);
+ states.insert(&transition.final_state);
+ inputs.insert(&transition.input_value);
+ if let Some(ref output) = transition.output {
+ outputs.insert(output);
+ }
+ }
+
+ let states_enum_name = Ident::new(&format!("{}State", struct_name), struct_name.span());
+ let initial_state_name = &input.initial_state;
+
+ let inputs_enum_name = Ident::new(&format!("{}Input", struct_name), struct_name.span());
+
+ let mut transition_cases = vec![];
+ for transition in input.transitions.iter() {
+ let initial_state = &transition.initial_state;
+ let input_value = &transition.input_value;
+ let final_state = &transition.final_state;
+ transition_cases.push(quote! {
+ (#states_enum_name::#initial_state, #inputs_enum_name::#input_value) => {
+ Some(#states_enum_name::#final_state)
+ }
+ });
+ }
+
+ let (outputs_repr, outputs_type, output_impl) = if !outputs.is_empty() {
+ let outputs_type_name = Ident::new(&format!("{}Output", struct_name), struct_name.span());
+ let outputs_repr = quote! {
+ #[derive(Debug, PartialEq)]
+ enum #outputs_type_name {
+ #(#outputs),*
+ }
+ };
+
+ let outputs_type = quote! { #outputs_type_name };
+
+ let mut output_cases = vec![];
+ for transition in input.transitions.iter() {
+ if let Some(output_value) = &transition.output {
+ let initial_state = &transition.initial_state;
+ let input_value = &transition.input_value;
+ output_cases.push(quote! {
+ (#states_enum_name::#initial_state, #inputs_enum_name::#input_value) => {
+ Some(#outputs_type_name::#output_value)
+ }
+ });
+ }
+ }
+
+ let output_impl = quote! {
+ match (state, input) {
+ #(#output_cases)*
+ _ => None,
+ }
+ };
+
+ (outputs_repr, outputs_type, output_impl)
+ } else {
+ (quote! {}, quote! { () }, quote! {None})
+ };
+
+ let output = quote! {
+ struct #struct_name;
+
+ #[derive(Debug, PartialEq)]
+ enum #states_enum_name {
+ #(#states),*
+ }
+
+ #[derive(Debug, PartialEq)]
+ enum #inputs_enum_name {
+ #(#inputs),*
+ }
+
+ #outputs_repr
+
+ impl rust_fsm::StateMachine for #struct_name {
+ type Input = #inputs_enum_name;
+ type State = #states_enum_name;
+ type Output = #outputs_type;
+ const INITIAL_STATE: Self::State = #states_enum_name::#initial_state_name;
+
+ fn transition(state: &Self::State, input: &Self::Input) -> Option<Self::State> {
+ match (state, input) {
+ #(#transition_cases)*
+ _ => None,
+ }
+ }
+
+ fn output(state: &Self::State, input: &Self::Input) -> Option<Self::Output> {
+ #output_impl
+ }
+ }
+ };
+
+ output.into()
+}