lib.rs

extern crate swc_common;
extern crate swc_ecmascript;
#[macro_use]
extern crate swc_atoms;
extern crate data_encoding;
extern crate dunce;
extern crate inflector;
extern crate path_slash;
extern crate pathdiff;
extern crate serde;
extern crate serde_bytes;
extern crate sha1;

mod decl_collector;
mod dependency_collector;
mod env_replacer;
mod fs;
mod global_replacer;
mod hoist;
mod modules;
mod node_replacer;
mod typeof_replacer;
mod utils;

use std::collections::{HashMap, HashSet};
use std::path::{Path, PathBuf};
use std::str::FromStr;

use path_slash::PathExt;
use serde::{Deserialize, Serialize};
use swc_common::comments::SingleThreadedComments;
use swc_common::errors::{DiagnosticBuilder, Emitter, Handler};
use swc_common::{chain, sync::Lrc, FileName, Globals, Mark, SourceMap};
use swc_ecmascript::ast::Module;
use swc_ecmascript::codegen::text_writer::JsWriter;
use swc_ecmascript::parser::lexer::Lexer;
use swc_ecmascript::parser::{EsConfig, PResult, Parser, StringInput, Syntax, TsConfig};
use swc_ecmascript::preset_env::{preset_env, Mode::Entry, Targets, Version, Versions};
use swc_ecmascript::transforms::fixer::paren_remover;
use swc_ecmascript::transforms::resolver;
use swc_ecmascript::transforms::{
  compat::reserved_words::reserved_words, fixer, helpers, hygiene,
  optimization::simplify::dead_branch_remover, optimization::simplify::expr_simplifier,
  pass::Optional, proposals::decorators, react, typescript,
};
use swc_ecmascript::visit::{FoldWith, VisitWith};

use decl_collector::*;
use dependency_collector::*;
use env_replacer::*;
use fs::inline_fs;
use global_replacer::GlobalReplacer;
use hoist::{hoist, CollectResult, HoistResult};
use modules::esm2cjs;
use node_replacer::NodeReplacer;
use typeof_replacer::*;
use utils::{CodeHighlight, Diagnostic, DiagnosticSeverity, SourceLocation, SourceType};

use crate::hoist::Collect;

type SourceMapBuffer = Vec<(swc_common::BytePos, swc_common::LineCol)>;

#[derive(Serialize, Debug, Deserialize)]
pub struct Config {
  filename: String,
  #[serde(with = "serde_bytes")]
  code: Vec<u8>,
  module_id: String,
  project_root: String,
  replace_env: bool,
  env: HashMap<swc_atoms::JsWord, swc_atoms::JsWord>,
  inline_fs: bool,
  insert_node_globals: bool,
  node_replacer: bool,
  is_browser: bool,
  is_worker: bool,
  is_type_script: bool,
  is_jsx: bool,
  jsx_pragma: Option<String>,
  jsx_pragma_frag: Option<String>,
  automatic_jsx_runtime: bool,
  jsx_import_source: Option<String>,
  decorators: bool,
  use_define_for_class_fields: bool,
  is_development: bool,
  react_refresh: bool,
  targets: Option<HashMap<String, String>>,
  source_maps: bool,
  scope_hoist: bool,
  source_type: SourceType,
  supports_module_workers: bool,
  is_library: bool,
  is_esm_output: bool,
  trace_bailouts: bool,
  is_swc_helpers: bool,
}

#[derive(Serialize, Debug, Default)]
pub struct TransformResult {
  #[serde(with = "serde_bytes")]
  code: Vec<u8>,
  map: Option<String>,
  shebang: Option<String>,
  dependencies: Vec<DependencyDescriptor>,
  hoist_result: Option<HoistResult>,
  symbol_result: Option<CollectResult>,
  diagnostics: Option<Vec<Diagnostic>>,
  needs_esm_helpers: bool,
  used_env: HashSet<swc_atoms::JsWord>,
  has_node_replacements: bool,
}

fn targets_to_versions(targets: &Option<HashMap<String, String>>) -> Option<Versions> {
  if let Some(targets) = targets {
    macro_rules! set_target {
      ($versions: ident, $name: ident) => {
        let version = targets.get(stringify!($name));
        if let Some(version) = version {
          if let Ok(version) = Version::from_str(version.as_str()) {
            $versions.$name = Some(version);
          }
        }
      };
    }

    let mut versions = Versions::default();
    set_target!(versions, chrome);
    set_target!(versions, opera);
    set_target!(versions, edge);
    set_target!(versions, firefox);
    set_target!(versions, safari);
    set_target!(versions, ie);
    set_target!(versions, ios);
    set_target!(versions, android);
    set_target!(versions, node);
    set_target!(versions, electron);
    return Some(versions);
  }

  None
}

#[derive(Debug, Clone, Default)]
pub struct ErrorBuffer(std::sync::Arc<std::sync::Mutex<Vec<swc_common::errors::Diagnostic>>>);

impl Emitter for ErrorBuffer {
  fn emit(&mut self, db: &DiagnosticBuilder) {
    self.0.lock().unwrap().push((**db).clone());
  }
}

pub fn transform(config: Config) -> Result<TransformResult, std::io::Error> {
  let mut result = TransformResult::default();
  let mut map_buf = vec![];

  let code = unsafe { std::str::from_utf8_unchecked(&config.code) };
  let source_map = Lrc::new(SourceMap::default());
  let module = parse(
    code,
    config.project_root.as_str(),
    config.filename.as_str(),
    &source_map,
    &config,
  );

  match module {
    Err(err) => {
      let error_buffer = ErrorBuffer::default();
      let handler = Handler::with_emitter(true, false, Box::new(error_buffer.clone()));
      err.into_diagnostic(&handler).emit();

      result.diagnostics = Some(error_buffer_to_diagnostics(&error_buffer, &source_map));
      Ok(result)
    }
    Ok((module, comments)) => {
      let mut module = module;
      result.shebang = match module.shebang {
        Some(shebang) => {
          module.shebang = None;
          Some(shebang.to_string())
        }
        None => None,
      };

      let mut global_deps = vec![];
      let mut fs_deps = vec![];
      let should_inline_fs = config.inline_fs
        && config.source_type != SourceType::Script
        && code.contains("readFileSync");
      let should_import_swc_helpers = match config.source_type {
        SourceType::Module => true,
        SourceType::Script => false,
      };

      swc_common::GLOBALS.set(&Globals::new(), || {
        let error_buffer = ErrorBuffer::default();
        let handler = Handler::with_emitter(true, false, Box::new(error_buffer.clone()));
        swc_common::errors::HANDLER.set(&handler, || {
          helpers::HELPERS.set(
            &helpers::Helpers::new(
              /* external helpers from @swc/helpers */ should_import_swc_helpers,
            ),
            || {
              let mut react_options = react::Options::default();
              if config.is_jsx {
                react_options.use_spread = Some(true);
                if let Some(jsx_pragma) = &config.jsx_pragma {
                  react_options.pragma = Some(jsx_pragma.clone());
                }
                if let Some(jsx_pragma_frag) = &config.jsx_pragma_frag {
                  react_options.pragma_frag = Some(jsx_pragma_frag.clone());
                }
                react_options.development = Some(config.is_development);
                react_options.refresh = if config.react_refresh {
                  Some(react::RefreshOptions::default())
                } else {
                  None
                };

                react_options.runtime = if config.automatic_jsx_runtime {
                  if let Some(import_source) = &config.jsx_import_source {
                    react_options.import_source = Some(import_source.clone());
                  }
                  Some(react::Runtime::Automatic)
                } else {
                  Some(react::Runtime::Classic)
                };
              }

              let global_mark = Mark::fresh(Mark::root());
              let unresolved_mark = Mark::fresh(Mark::root());
              module = {
                let mut passes = chain!(
                  // Decorators can use type information, so must run before the TypeScript pass.
                  Optional::new(
                    decorators::decorators(decorators::Config {
                      legacy: true,
                      use_define_for_class_fields: config.use_define_for_class_fields,
                      // Always disabled for now, SWC's implementation doesn't match TSC.
                      emit_metadata: false,
                    }),
                    config.decorators
                  ),
                  Optional::new(
                    typescript::strip_with_jsx(
                      source_map.clone(),
                      typescript::Config {
                        pragma: react_options.pragma.clone(),
                        pragma_frag: react_options.pragma_frag.clone(),
                        ..Default::default()
                      },
                      Some(&comments),
                      global_mark,
                    ),
                    config.is_type_script && config.is_jsx
                  ),
                  Optional::new(
                    typescript::strip(global_mark),
                    config.is_type_script && !config.is_jsx
                  ),
                  resolver(unresolved_mark, global_mark, config.is_type_script),
                  Optional::new(
                    react::react(
                      source_map.clone(),
                      Some(&comments),
                      react_options,
                      global_mark
                    ),
                    config.is_jsx
                  ),
                );

                module.fold_with(&mut passes)
              };

              let mut decls = collect_decls(&module);

              let mut preset_env_config = swc_ecmascript::preset_env::Config {
                dynamic_import: true,
                ..Default::default()
              };
              let versions = targets_to_versions(&config.targets);
              let mut should_run_preset_env = false;
              if !config.is_swc_helpers {
                // Avoid transpiling @swc/helpers so that we don't cause infinite recursion.
                // Filter the versions for preset_env only so that syntax support checks
                // (e.g. in esm2cjs) still work correctly.
                if let Some(versions) = versions {
                  should_run_preset_env = true;
                  preset_env_config.targets = Some(Targets::Versions(versions));
                  preset_env_config.shipped_proposals = true;
                  preset_env_config.mode = Some(Entry);
                  preset_env_config.bugfixes = true;
                }
              }

              let mut diagnostics = vec![];
              let module = {
                let mut passes = chain!(
                  Optional::new(
                    TypeofReplacer { decls: &decls },
                    config.source_type != SourceType::Script
                  ),
                  // Inline process.env and process.browser
                  Optional::new(
                    EnvReplacer {
                      replace_env: config.replace_env,
                      env: &config.env,
                      is_browser: config.is_browser,
                      decls: &decls,
                      used_env: &mut result.used_env,
                      source_map: &source_map,
                      diagnostics: &mut diagnostics
                    },
                    config.source_type != SourceType::Script
                  ),
                  paren_remover(Some(&comments)),
                  // Simplify expressions and remove dead branches so that we
                  // don't include dependencies inside conditionals that are always false.
                  expr_simplifier(unresolved_mark, Default::default()),
                  dead_branch_remover(unresolved_mark),
                  // Inline Node fs.readFileSync calls
                  Optional::new(
                    inline_fs(
                      config.filename.as_str(),
                      source_map.clone(),
                      // TODO this clone is unnecessary if we get the lifetimes right
                      decls.clone(),
                      global_mark,
                      &config.project_root,
                      &mut fs_deps,
                    ),
                    should_inline_fs
                  ),
                );

                module.fold_with(&mut passes)
              };

              let module = module.fold_with(
                // Replace __dirname and __filename with placeholders in Node env
                &mut Optional::new(
                  NodeReplacer {
                    source_map: &source_map,
                    items: &mut global_deps,
                    global_mark,
                    globals: HashMap::new(),
                    project_root: Path::new(&config.project_root),
                    filename: Path::new(&config.filename),
                    decls: &mut decls,
                    scope_hoist: config.scope_hoist,
                    has_node_replacements: &mut result.has_node_replacements,
                  },
                  config.node_replacer,
                ),
              );

              let module = {
                let mut passes = chain!(
                  // Insert dependencies for node globals
                  Optional::new(
                    GlobalReplacer {
                      source_map: &source_map,
                      items: &mut global_deps,
                      global_mark,
                      globals: HashMap::new(),
                      project_root: Path::new(&config.project_root),
                      filename: Path::new(&config.filename),
                      decls: &mut decls,
                      scope_hoist: config.scope_hoist
                    },
                    config.insert_node_globals
                  ),
                  // Transpile new syntax to older syntax if needed
                  Optional::new(
                    preset_env(
                      global_mark,
                      Some(&comments),
                      preset_env_config,
                      Default::default(),
                    ),
                    should_run_preset_env,
                  ),
                  // Inject SWC helpers if needed.
                  helpers::inject_helpers(),
                );

                module.fold_with(&mut passes)
              };

              // Flush (JsWord, SyntaxContexts) into unique names and reresolve to
              // set global_mark for all nodes, even generated ones.
              // - This changes the syntax context ids and therefore invalidates decls
              // - This will also remove any other other marks (like ignore_mark)
              // This only needs to be done if preset_env ran because all other transforms
              // insert declarations with global_mark (even though they are generated).
              let (decls, module) = if config.scope_hoist && should_run_preset_env {
                let module = module.fold_with(&mut chain!(
                  hygiene(),
                  resolver(unresolved_mark, global_mark, false)
                ));
                (collect_decls(&module), module)
              } else {
                (decls, module)
              };

              let ignore_mark = Mark::fresh(Mark::root());
              let module = module.fold_with(
                // Collect dependencies
                &mut dependency_collector(
                  &source_map,
                  &mut result.dependencies,
                  &decls,
                  ignore_mark,
                  &config,
                  &mut diagnostics,
                ),
              );

              diagnostics.extend(error_buffer_to_diagnostics(&error_buffer, &source_map));

              if diagnostics
                .iter()
                .any(|d| d.severity == DiagnosticSeverity::Error)
              {
                result.diagnostics = Some(diagnostics);
                return Ok(result);
              }

              let mut collect = Collect::new(
                source_map.clone(),
                decls,
                ignore_mark,
                global_mark,
                config.trace_bailouts,
              );
              module.visit_with(&mut collect);
              if let Some(bailouts) = &collect.bailouts {
                diagnostics.extend(bailouts.iter().map(|bailout| bailout.to_diagnostic()));
              }

              let module = if config.scope_hoist {
                let res = hoist(module, config.module_id.as_str(), &collect);
                match res {
                  Ok((module, hoist_result, hoist_diagnostics)) => {
                    result.hoist_result = Some(hoist_result);
                    diagnostics.extend(hoist_diagnostics);
                    module
                  }
                  Err(diagnostics) => {
                    result.diagnostics = Some(diagnostics);
                    return Ok(result);
                  }
                }
              } else {
                // Bail if we could not statically analyze.
                if collect.static_cjs_exports && !collect.should_wrap {
                  result.symbol_result = Some(collect.into());
                }

                let (module, needs_helpers) = esm2cjs(module, versions);
                result.needs_esm_helpers = needs_helpers;
                module
              };

              let program = {
                let mut passes = chain!(reserved_words(), hygiene(), fixer(Some(&comments)),);
                module.fold_with(&mut passes)
              };

              result.dependencies.extend(global_deps);
              result.dependencies.extend(fs_deps);

              if !diagnostics.is_empty() {
                result.diagnostics = Some(diagnostics);
              }

              let (buf, mut src_map_buf) =
                emit(source_map.clone(), comments, &program, config.source_maps)?;
              if config.source_maps
                && source_map
                  .build_source_map(&mut src_map_buf)
                  .to_writer(&mut map_buf)
                  .is_ok()
              {
                result.map = Some(String::from_utf8(map_buf).unwrap());
              }
              result.code = buf;
              Ok(result)
            },
          )
        })
      })
    }
  }
}

fn parse(
  code: &str,
  project_root: &str,
  filename: &str,
  source_map: &Lrc<SourceMap>,
  config: &Config,
) -> PResult<(Module, SingleThreadedComments)> {
  // Attempt to convert the path to be relative to the project root.
  // If outside the project root, use an absolute path so that if the project root moves the path still works.
  let filename: PathBuf = if let Ok(relative) = Path::new(filename).strip_prefix(project_root) {
    relative.to_slash_lossy().into()
  } else {
    filename.into()
  };
  let source_file = source_map.new_source_file(FileName::Real(filename), code.into());

  let comments = SingleThreadedComments::default();
  let syntax = if config.is_type_script {
    Syntax::Typescript(TsConfig {
      tsx: config.is_jsx,
      decorators: config.decorators,
      ..Default::default()
    })
  } else {
    Syntax::Es(EsConfig {
      jsx: config.is_jsx,
      export_default_from: true,
      decorators: config.decorators,
      ..Default::default()
    })
  };

  let lexer = Lexer::new(
    syntax,
    Default::default(),
    StringInput::from(&*source_file),
    Some(&comments),
  );

  let mut parser = Parser::new_from(lexer);
  match parser.parse_module() {
    Err(err) => Err(err),
    Ok(module) => Ok((module, comments)),
  }
}

fn emit(
  source_map: Lrc<SourceMap>,
  comments: SingleThreadedComments,
  program: &Module,
  source_maps: bool,
) -> Result<(Vec<u8>, SourceMapBuffer), std::io::Error> {
  let mut src_map_buf = vec![];
  let mut buf = vec![];
  {
    let writer = Box::new(JsWriter::new(
      source_map.clone(),
      "\n",
      &mut buf,
      if source_maps {
        Some(&mut src_map_buf)
      } else {
        None
      },
    ));
    let config = swc_ecmascript::codegen::Config {
      minify: false,
      ascii_only: false,
      target: swc_ecmascript::ast::EsVersion::Es5,
    };
    let mut emitter = swc_ecmascript::codegen::Emitter {
      cfg: config,
      comments: Some(&comments),
      cm: source_map,
      wr: writer,
    };

    emitter.emit_module(program)?;
  }

  Ok((buf, src_map_buf))
}

fn error_buffer_to_diagnostics(
  error_buffer: &ErrorBuffer,
  source_map: &Lrc<SourceMap>,
) -> Vec<Diagnostic> {
  let s = error_buffer.0.lock().unwrap().clone();
  s.iter()
    .map(|diagnostic| {
      let message = diagnostic.message();
      let span = diagnostic.span.clone();
      let suggestions = diagnostic.suggestions.clone();

      let span_labels = span.span_labels();
      let code_highlights = if !span_labels.is_empty() {
        let mut highlights = vec![];
        for span_label in span_labels {
          highlights.push(CodeHighlight {
            message: span_label.label,
            loc: SourceLocation::from(source_map, span_label.span),
          });
        }

        Some(highlights)
      } else {
        None
      };

      let hints = if !suggestions.is_empty() {
        Some(
          suggestions
            .into_iter()
            .map(|suggestion| suggestion.msg)
            .collect(),
        )
      } else {
        None
      };

      Diagnostic {
        message,
        code_highlights,
        hints,
        show_environment: false,
        severity: DiagnosticSeverity::Error,
        documentation_url: None,
      }
    })
    .collect()
}