boa/boa_cli/src/main.rs

#![deny(
    unused_qualifications,
    clippy::all,
    unused_qualifications,
    unused_import_braces,
    unused_lifetimes,
    unreachable_pub,
    trivial_numeric_casts,
    rustdoc,
    missing_debug_implementations,
    missing_copy_implementations,
    deprecated_in_future,
    non_ascii_idents,
    rust_2018_compatibility,
    rust_2018_idioms,
    future_incompatible,
    nonstandard_style
)]
#![warn(clippy::perf, clippy::single_match_else, clippy::dbg_macro)]
#![allow(
    clippy::missing_inline_in_public_items,
    clippy::cognitive_complexity,
    clippy::must_use_candidate,
    clippy::missing_errors_doc,
    clippy::as_conversions
)]

use boa::{
    exec::Interpreter,
    forward_val,
    realm::Realm,
    syntax::ast::{node::StatementList, token::Token},
};
use colored::*;
use lazy_static::lazy_static;
use regex::{Captures, Regex};
use rustyline::{
    config::Config,
    error::ReadlineError,
    highlight::Highlighter,
    validate::{MatchingBracketValidator, ValidationContext, ValidationResult, Validator},
    EditMode, Editor,
};
use rustyline_derive::{Completer, Helper, Hinter};
use std::borrow::Cow;
use std::collections::HashSet;
use std::{fs::read_to_string, path::PathBuf};
use structopt::{clap::arg_enum, StructOpt};

#[cfg(all(target_arch = "x86_64", target_os = "linux", target_env = "gnu"))]
#[cfg_attr(
    all(target_arch = "x86_64", target_os = "linux", target_env = "gnu"),
    global_allocator
)]
static ALLOC: jemallocator::Jemalloc = jemallocator::Jemalloc;

/// CLI configuration for Boa.
static CLI_HISTORY: &str = ".boa_history";

// Added #[allow(clippy::option_option)] because to StructOpt an Option<Option<T>>
// is an optional argument that optionally takes a value ([--opt=[val]]).
// https://docs.rs/structopt/0.3.11/structopt/#type-magic
#[allow(clippy::option_option)]
#[derive(Debug, StructOpt)]
#[structopt(author, about, name = "boa")]
struct Opt {
    /// The JavaScript file(s) to be evaluated.
    #[structopt(name = "FILE", parse(from_os_str))]
    files: Vec<PathBuf>,

    /// Dump the token stream to stdout with the given format.
    #[structopt(
        long,
        short = "t",
        value_name = "FORMAT",
        possible_values = &DumpFormat::variants(),
        case_insensitive = true,
        conflicts_with = "dump-ast"
    )]
    dump_tokens: Option<Option<DumpFormat>>,

    /// Dump the ast to stdout with the given format.
    #[structopt(
        long,
        short = "a",
        value_name = "FORMAT",
        possible_values = &DumpFormat::variants(),
        case_insensitive = true
    )]
    dump_ast: Option<Option<DumpFormat>>,

    /// Use vi mode in the REPL
    #[structopt(long = "vi")]
    vi_mode: bool,
}

impl Opt {
    /// Returns whether a dump flag has been used.
    fn has_dump_flag(&self) -> bool {
        self.dump_tokens.is_some() || self.dump_ast.is_some()
    }
}

arg_enum! {
    /// The different types of format available for dumping.
    ///
    // NOTE: This can easily support other formats just by
    // adding a field to this enum and adding the necessary
    // implementation. Example: Toml, Html, etc.
    //
    // NOTE: The fields of this enum are not doc comments because
    // arg_enum! macro does not support it.
    #[derive(Debug)]
    enum DumpFormat {
        // This is the default format that you get from std::fmt::Debug.
        Debug,

        // This is a minified json format.
        Json,

        // This is a pretty printed json format.
        JsonPretty,
    }
}

/// Lexes the given source code into a stream of tokens and return it.
///
/// Returns a error of type String with a message,
/// if the source has a syntax error.
fn lex_source(src: &str) -> Result<Vec<Token>, String> {
    use boa::syntax::lexer::Lexer;

    let mut lexer = Lexer::new(src);
    lexer.lex().map_err(|e| format!("SyntaxError: {}", e))?;
    Ok(lexer.tokens)
}

/// Parses the the token stream into a ast and returns it.
///
/// Returns a error of type String with a message,
/// if the token stream has a parsing error.
fn parse_tokens(tokens: Vec<Token>) -> Result<StatementList, String> {
    use boa::syntax::parser::Parser;

    Parser::new(&tokens)
        .parse_all()
        .map_err(|e| format!("ParsingError: {}", e))
}

/// Dumps the token stream or ast to stdout depending on the given arguments.
///
/// Returns a error of type String with a error message,
/// if the source has a syntax or parsing error.
fn dump(src: &str, args: &Opt) -> Result<(), String> {
    let tokens = lex_source(src)?;

    if let Some(ref arg) = args.dump_tokens {
        match arg {
            Some(format) => match format {
                DumpFormat::Debug => println!("{:#?}", tokens),
                DumpFormat::Json => println!("{}", serde_json::to_string(&tokens).unwrap()),
                DumpFormat::JsonPretty => {
                    println!("{}", serde_json::to_string_pretty(&tokens).unwrap())
                }
            },
            // Default token stream dumping format.
            None => println!("{:#?}", tokens),
        }
    } else if let Some(ref arg) = args.dump_ast {
        let ast = parse_tokens(tokens)?;

        match arg {
            Some(format) => match format {
                DumpFormat::Debug => println!("{:#?}", ast),
                DumpFormat::Json => println!("{}", serde_json::to_string(&ast).unwrap()),
                DumpFormat::JsonPretty => {
                    println!("{}", serde_json::to_string_pretty(&ast).unwrap())
                }
            },
            // Default ast dumping format.
            None => println!("{:#?}", ast),
        }
    }

    Ok(())
}

pub fn main() -> Result<(), std::io::Error> {
    let args = Opt::from_args();

    let realm = Realm::create();

    let mut engine = Interpreter::new(realm);

    for file in &args.files {
        let buffer = read_to_string(file)?;

        if args.has_dump_flag() {
            if let Err(e) = dump(&buffer, &args) {
                eprintln!("{}", e);
            }
        } else {
            match forward_val(&mut engine, &buffer) {
                Ok(v) => print!("{}", v.to_string()),
                Err(v) => eprint!("{}", v.to_string()),
            }
        }
    }

    if args.files.is_empty() {
        let config = Config::builder()
            .keyseq_timeout(1)
            .edit_mode(if args.vi_mode {
                EditMode::Vi
            } else {
                EditMode::Emacs
            })
            .build();

        let mut editor = Editor::with_config(config);
        let _ = editor.load_history(CLI_HISTORY);
        editor.set_helper(Some(RLHelper {
            highlighter: LineHighlighter,
            validator: MatchingBracketValidator::new(),
        }));

        let readline = ">> ".cyan().bold().to_string();

        loop {
            match editor.readline(&readline) {
                Ok(line) if line == ".exit" => break,
                Err(ReadlineError::Interrupted) | Err(ReadlineError::Eof) => break,

                Ok(line) => {
                    editor.add_history_entry(&line);

                    if args.has_dump_flag() {
                        if let Err(e) = dump(&line, &args) {
                            eprintln!("{}", e);
                        }
                    } else {
                        match forward_val(&mut engine, line.trim_end()) {
                            Ok(v) => println!("{}", v),
                            Err(v) => eprintln!("{}: {}", "Uncaught".red(), v.to_string().red()),
                        }
                    }
                }

                Err(err) => {
                    eprintln!("Unknown error: {:?}", err);
                    break;
                }
            }
        }

        editor.save_history(CLI_HISTORY).unwrap();
    }

    Ok(())
}

#[derive(Completer, Helper, Hinter)]
struct RLHelper {
    highlighter: LineHighlighter,
    validator: MatchingBracketValidator,
}

impl Validator for RLHelper {
    fn validate(&self, ctx: &mut ValidationContext<'_>) -> Result<ValidationResult, ReadlineError> {
        self.validator.validate(ctx)
    }

    fn validate_while_typing(&self) -> bool {
        self.validator.validate_while_typing()
    }
}

impl Highlighter for RLHelper {
    fn highlight_hint<'h>(&self, hint: &'h str) -> Cow<'h, str> {
        hint.into()
    }

    fn highlight<'l>(&self, line: &'l str, pos: usize) -> Cow<'l, str> {
        self.highlighter.highlight(line, pos)
    }

    fn highlight_candidate<'c>(
        &self,
        candidate: &'c str,
        _completion: rustyline::CompletionType,
    ) -> Cow<'c, str> {
        self.highlighter.highlight(candidate, 0)
    }

    fn highlight_char(&self, line: &str, _: usize) -> bool {
        !line.is_empty()
    }
}

lazy_static! {
    static ref KEYWORDS: HashSet<&'static str> = {
        let mut keywords = HashSet::new();
        keywords.insert("break");
        keywords.insert("case");
        keywords.insert("catch");
        keywords.insert("class");
        keywords.insert("const");
        keywords.insert("continue");
        keywords.insert("default");
        keywords.insert("delete");
        keywords.insert("do");
        keywords.insert("else");
        keywords.insert("export");
        keywords.insert("extends");
        keywords.insert("finally");
        keywords.insert("for");
        keywords.insert("function");
        keywords.insert("if");
        keywords.insert("import");
        keywords.insert("instanceof");
        keywords.insert("new");
        keywords.insert("return");
        keywords.insert("super");
        keywords.insert("switch");
        keywords.insert("this");
        keywords.insert("throw");
        keywords.insert("try");
        keywords.insert("typeof");
        keywords.insert("var");
        keywords.insert("void");
        keywords.insert("while");
        keywords.insert("with");
        keywords.insert("yield");
        keywords.insert("await");
        keywords.insert("enum");
        keywords.insert("let");
        keywords
    };
}

struct LineHighlighter;

impl Highlighter for LineHighlighter {
    fn highlight<'l>(&self, line: &'l str, _: usize) -> Cow<'l, str> {
        let mut coloured = line.to_string();

        let reg = Regex::new(
            r"(?x)
            (?P<identifier>[$A-z_]+[$A-z_0-9]*) |
            (?P<op>[+\-/*%~^!&|=<>,.;:])",
        )
        .unwrap();

        coloured = reg
            .replace_all(&coloured, |caps: &Captures<'_>| {
                if let Some(cap) = caps.name("identifier") {
                    match cap.as_str() {
                        "true" | "false" | "null" | "Infinity" => cap.as_str().purple().to_string(),
                        "undefined" => cap.as_str().truecolor(100, 100, 100).to_string(),
                        identifier if KEYWORDS.contains(identifier) => {
                            cap.as_str().yellow().bold().to_string()
                        }
                        _ => cap.as_str().to_string(),
                    }
                } else if let Some(cap) = caps.name("op") {
                    cap.as_str().green().to_string()
                } else {
                    caps[0].to_string()
                }
            })
            .to_string();

        coloured.into()
    }
}