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//! GameShell - A fast and lightweight shell for interactive work in Rust //! //! GameShell is a little lisp-like command shell made to be embedded in rust programs. It has no //! runtime and attempts to call given handlers as fast as possible. This means that GameShell is //! made for one-time commands, where the heavy lifting is done in your specified handler //! functions. It does not do any JIT/compilation or bytecode conversion, but goes straight to a //! handler and calls it. //! //! # Language # //! //! The language is just //! ```ignore //! command argument (subcommand argument ...) (#literal string inside here) argument ... //! ``` //! //! If an opened parenthesis is not closed on a newline, the next line is also considered part of //! the command: //! ```ignore //! command ( //! subcommand //! argument //! ... //! ) argument ... //! ``` //! //! # Example # //! //! This example sets up a basic interpreter and a single handler for a single command. More //! commands and handlers can be added. //! //! ``` //! use gameshell::{ //! predicates::*, types::Type, Evaluator, GameShell, IncConsumer, //! }; //! use std::str::from_utf8; //! //! fn main() { //! // This is the input stream, GameShell will handle anything that implements //! // std::io::Read, and will efficiently acquire data from such a stream. //! let read = b"Lorem ipsum 1.23\n"; //! // This is the output stream, GameShell will use this to write messages out. //! let mut write = [0u8; 12]; //! //! // A gameshell is created by supplying a context object (here 0u8), and an IO stream. //! let mut eval = GameShell::new(0u8, &read[..], &mut write[..]); //! //! // We then register command handler functions to GameShell, such that it can run commands //! // when reading from the input stream //! // //! // Each command handler takes a `&mut Context` (here u8), and a list of arguments. //! // It returns a result, `Ok` indicating a successful computation, //! // and an `Err` indicating an error, aborting any nested computation and writing out the //! // error message to the writer. //! fn handler(context: &mut u8, args: &[Type]) -> Result<String, String> { //! *context += 1; //! println!["Got types: {:?}", args[0]]; //! Ok("Hello world!".into()) //! } //! //! // Register the handler and associate it with the command "Lorem ipsum <f32>". //! // The first element in the pair is a string literal on which we match the command tree, //! // and the second argument is an arbitrary `Decider` which parses our input data into a //! // `Type`. Deciders can consume as many elements as they like. //! eval.register((&[("Lorem", None), ("ipsum", ANY_F32)], handler)).unwrap(); //! //! // Run the command loop, keeps reading from the tcp buffer until the buffer has no more //! // elements. When reading from a `TcpStream` this call will block until the stream is //! // closed. The `buffer` provided here is the buffer for parsing a single incoming whole //! // command. If the command exceeds this size, the command will be discarded and the //! // connection severed. //! let buffer = &mut [0u8; 1024]; //! eval.run(buffer); //! //! // Ensure that we have run at least once, our starting context was 0, which should now be 1 //! assert_eq![1, *eval.context()]; //! // Our Ok message has been written to the writer //! assert_eq!["Hello world!", from_utf8(&write[..]).unwrap()]; //! } //! ``` //! //! # Why does a command handler return a string instead of a type? # //! //! Because nested commands may reinterpret the string in any way they like, according to an //! arbitrary decider. Thus, we can't return types. This is an inefficiency to allow for proper //! error checking in nested calls. //! //! As unfortunate as that is, this library is not meant to sacrifice usability for speed. If you //! want speed, you can just collapse two commands into one and use a single handler, since pure //! Rust will always beat this library at speed. //! //! # Builtin commands # //! //! GameShell has 2 builtin commands: //! ```ignore //! ? //! ``` //! List all registered commands and their potential arguments. An argument to this command will //! regex filter the output: `? lorem`. //! and //! ```ignore //! autocomplete //! ``` //! Autocomplete a query. //! //! These commands return strings that contain useful information to be displayed to the user. #![deny( missing_docs, trivial_casts, trivial_numeric_casts, unsafe_code, unused_import_braces, unused_qualifications )] pub use crate::{evaluator::Evaluator, incconsumer::IncConsumer}; use crate::{ incconsumer::{Consumption, Process, Validation}, types::Type, }; use cmdmat::RegError; pub use cmdmat::{self, Spec}; pub use metac::{Evaluate, PartialParse, PartialParseOp}; use std::{ io::{Read, Write}, str::from_utf8, }; pub mod evaluator; mod incconsumer; pub mod predicates; pub mod types; /// Feedback provided by the interpreter. All results are either a success string or an error /// string. pub type Feedback = Result<String, String>; /// The main virtual machine wrapper for a game shell /// /// This wrapper consumes an input and output stream through which it writes messages. pub struct GameShell<'a, C, R: Read, W: Write> { evaluator: Evaluator<'a, C>, parser: PartialParse, reader: R, writer: W, } impl<'a, C, R: Read, W: Write> GameShell<'a, C, R, W> { /// Spawn a new gameshell with a given context and readers/writers pub fn new(context: C, reader: R, writer: W) -> Self { Self { evaluator: Evaluator::new(context), parser: PartialParse::default(), reader, writer, } } /// Get a reference to the current evaluator pub fn evaluator(&mut self) -> &mut Evaluator<'a, C> { &mut self.evaluator } /// Get a reference to the current context pub fn context(&self) -> &C { self.evaluator.context() } /// Get a mutable reference to the current context pub fn context_mut(&mut self) -> &mut C { self.evaluator.context_mut() } /// Register a command specificator to this gameshell instance pub fn register(&mut self, spec: Spec<'_, 'a, Type, String, C>) -> Result<(), RegError> { self.evaluator.register(spec) } /// Register multiple command specifications to this gameshell instance pub fn register_many( &mut self, spec: &[Spec<'_, 'a, Type, String, C>], ) -> Result<(), RegError> { self.evaluator.register_many(spec) } } impl<'a, C, R: Read, W: Write> IncConsumer for GameShell<'a, C, R, W> { fn consume(&mut self, output: &mut [u8]) -> Consumption { if output.is_empty() { let _ = self .writer .write(b"Input too big for buffer, terminating instance"); return Consumption::Stop; } match self.reader.read(output) { Ok(0) => Consumption::Stop, Ok(count) => Consumption::Consumed(count), Err(_) => Consumption::Stop, } } fn validate(&mut self, input: u8) -> Validation { match self.parser.parse_increment(input) { PartialParseOp::Ready => Validation::Ready, PartialParseOp::Unready => Validation::Unready, PartialParseOp::Discard => Validation::Discard, } } fn process(&mut self, input: &[u8]) -> Process { let string = from_utf8(input); if let Ok(string) = string { let result = self.evaluator.interpret_single(string); if let Ok(result) = result { match result { Feedback::Ok(res) => { if !res.is_empty() { if self.writer.write_all(res.as_bytes()).is_err() { return Process::Stop; } } else if self.writer.write_all(b"Ok").is_err() { return Process::Stop; } } Feedback::Err(res) => { if self .writer .write_all(format!["Err: {}", res].as_bytes()) .is_err() { return Process::Stop; } } } if self.writer.flush().is_err() { return Process::Stop; } } else { if self .writer .write_all(b"Unable to complete query (parse error)") .is_err() { return Process::Stop; } if self.writer.flush().is_err() { return Process::Stop; } } Process::Continue } else { Process::Stop } } } #[cfg(test)] mod tests { use super::*; use crate::predicates::*; #[test] fn basic_case() { let read = b"Lorem ipsum"; let mut write = [0u8; 10]; let mut shell = GameShell::new(0u8, &read[..], &mut write[..]); assert_eq![&mut 0u8, shell.context_mut()]; } #[test] fn basic_byte_stream() { let read = b"call 1.23\n"; let mut write = [0u8; 10]; let mut eval = GameShell::new(0u8, &read[..], &mut write[..]); fn handler(context: &mut u8, _args: &[Type]) -> Result<String, String> { *context += 1; Ok("".into()) } eval.register((&[("call", ANY_F32)], handler)).unwrap(); let buffer = &mut [0u8; 1024]; eval.run(buffer); assert_eq![1, *eval.context()]; } #[test] fn discard_stream_first_command_too_big() { let read = b"call 1.2\ncall 3.1\ncall 99.9999\ncall 1.0"; let mut write = [0u8; 1024]; let mut eval = GameShell::new(0u8, &read[..], &mut write[..]); fn handler(context: &mut u8, _args: &[Type]) -> Result<String, String> { *context += 1; Ok("".into()) } eval.register((&[("call", ANY_F32)], handler)).unwrap(); let buffer = &mut [0u8; 10]; eval.run(buffer); assert_eq![2, *eval.context()]; assert_eq![ "Input too big for buffer, terminating instance", from_utf8(&write[4..50]).unwrap() ]; } #[test] fn partial_read_succeeds() { let read = b"call 1.2\nrock 3.1\n"; let mut write = [0u8; 1024]; let mut eval = GameShell::new(0f32, &read[..], &mut write[..]); fn handler(context: &mut f32, args: &[Type]) -> Result<String, String> { match args[0] { Type::F32(number) => *context += number, _ => panic![], } Ok("".into()) } eval.register((&[("call", ANY_F32)], handler)).unwrap(); eval.register((&[("rock", ANY_F32)], handler)).unwrap(); let buffer = &mut [0u8; 12]; eval.run(buffer); assert_eq![4.3, *eval.context()]; } }