deno/src/deno_dir.rs

// Copyright 2018 the Deno authors. All rights reserved. MIT license.
use dirs;
use errors::DenoError;
use errors::DenoResult;
use errors::ErrorKind;
use fs as deno_fs;
use http_util;
use msg;
use ring;
use std;
use std::fmt::Write;
use std::fs;
use std::path::Path;
use std::path::PathBuf;
use std::result::Result;
#[cfg(test)]
use tempfile::TempDir;
use url;
use url::Url;

pub struct DenoDir {
  // Example: /Users/rld/.deno/
  pub root: PathBuf,
  // In the Go code this was called SrcDir.
  // This is where we cache http resources. Example:
  // /Users/rld/.deno/deps/github.com/ry/blah.js
  pub gen: PathBuf,
  // In the Go code this was called CacheDir.
  // This is where we cache compilation outputs. Example:
  // /Users/rld/.deno/gen/f39a473452321cacd7c346a870efb0e3e1264b43.js
  pub deps: PathBuf,
  // This splits to http and https deps
  pub deps_http: PathBuf,
  pub deps_https: PathBuf,
  // If remote resources should be reloaded.
  reload: bool,
}

impl DenoDir {
  // Must be called before using any function from this module.
  // https://github.com/denoland/deno/blob/golang/deno_dir.go#L99-L111
  pub fn new(
    reload: bool,
    custom_root: Option<&Path>,
  ) -> std::io::Result<DenoDir> {
    // Only setup once.
    let home_dir = dirs::home_dir().expect("Could not get home directory.");
    let default = home_dir.join(".deno");

    let root: PathBuf = match custom_root {
      None => default,
      Some(path) => path.to_path_buf(),
    };
    let gen = root.as_path().join("gen");
    let deps = root.as_path().join("deps");
    let deps_http = deps.join("http");
    let deps_https = deps.join("https");

    let deno_dir = DenoDir {
      root,
      gen,
      deps,
      deps_http,
      deps_https,
      reload,
    };
    deno_fs::mkdir(deno_dir.gen.as_ref(), 0o755)?;
    deno_fs::mkdir(deno_dir.deps.as_ref(), 0o755)?;
    deno_fs::mkdir(deno_dir.deps_http.as_ref(), 0o755)?;
    deno_fs::mkdir(deno_dir.deps_https.as_ref(), 0o755)?;

    debug!("root {}", deno_dir.root.display());
    debug!("gen {}", deno_dir.gen.display());
    debug!("deps {}", deno_dir.deps.display());
    debug!("deps_http {}", deno_dir.deps_http.display());
    debug!("deps_https {}", deno_dir.deps_https.display());

    Ok(deno_dir)
  }

  // https://github.com/denoland/deno/blob/golang/deno_dir.go#L32-L35
  pub fn cache_path(
    self: &DenoDir,
    filename: &str,
    source_code: &str,
  ) -> (PathBuf, PathBuf) {
    let cache_key = source_code_hash(filename, source_code);
    (
      self.gen.join(cache_key.to_string() + ".js"),
      self.gen.join(cache_key.to_string() + ".js.map"),
    )
  }

  fn load_cache(
    self: &DenoDir,
    filename: &str,
    source_code: &str,
  ) -> Result<(String, String), std::io::Error> {
    let (output_code, source_map) = self.cache_path(filename, source_code);
    debug!(
      "load_cache code: {} map: {}",
      output_code.display(),
      source_map.display()
    );
    let read_output_code = fs::read_to_string(&output_code)?;
    let read_source_map = fs::read_to_string(&source_map)?;
    Ok((read_output_code, read_source_map))
  }

  pub fn code_cache(
    self: &DenoDir,
    filename: &str,
    source_code: &str,
    output_code: &str,
    source_map: &str,
  ) -> std::io::Result<()> {
    let (cache_path, source_map_path) = self.cache_path(filename, source_code);
    // TODO(ry) This is a race condition w.r.t to exists() -- probably should
    // create the file in exclusive mode. A worry is what might happen is there
    // are two processes and one reads the cache file while the other is in the
    // midst of writing it.
    if cache_path.exists() && source_map_path.exists() {
      Ok(())
    } else {
      fs::write(cache_path, output_code.as_bytes())?;
      fs::write(source_map_path, source_map.as_bytes())?;
      Ok(())
    }
  }

  // Prototype https://github.com/denoland/deno/blob/golang/deno_dir.go#L37-L73
  fn fetch_remote_source(
    self: &DenoDir,
    module_name: &str,
    filename: &str,
  ) -> DenoResult<(String, msg::MediaType)> {
    let p = Path::new(filename);
    // We write a special ".mime" file into the `.deno/deps` directory along side the
    // cached file, containing just the media type.
    let mut media_type_filename = filename.to_string();
    media_type_filename.push_str(".mime");
    let mt = Path::new(&media_type_filename);

    let src = if self.reload || !p.exists() {
      println!("Downloading {}", module_name);
      let (source, content_type) = http_util::fetch_sync_string(module_name)?;
      match p.parent() {
        Some(ref parent) => fs::create_dir_all(parent),
        None => Ok(()),
      }?;
      deno_fs::write_file(&p, source.as_bytes(), 0o666)?;
      deno_fs::write_file(&mt, content_type.as_bytes(), 0o666)?;
      (source, map_content_type(&p, Some(&content_type)))
    } else {
      let source = fs::read_to_string(&p)?;
      let content_type = fs::read_to_string(&mt)?;
      (source, map_content_type(&p, Some(&content_type)))
    };
    Ok(src)
  }

  // Prototype: https://github.com/denoland/deno/blob/golang/os.go#L122-L138
  fn get_source_code(
    self: &DenoDir,
    module_name: &str,
    filename: &str,
  ) -> DenoResult<CodeFetchOutput> {
    if module_name.starts_with(ASSET_PREFIX) {
      panic!("Asset resolution should be done in JS, not Rust.");
    }
    let is_module_remote = is_remote(module_name);
    let use_extension = |ext| {
      let module_name = format!("{}{}", module_name, ext);
      let filename = format!("{}{}", filename, ext);
      let (source_code, media_type) = if is_module_remote {
        self.fetch_remote_source(&module_name, &filename)?
      } else {
        assert_eq!(
          module_name, filename,
          "if a module isn't remote, it should have the same filename"
        );
        let path = Path::new(&filename);
        (fs::read_to_string(path)?, map_content_type(path, None))
      };
      Ok(CodeFetchOutput {
        module_name: module_name.to_string(),
        filename: filename.to_string(),
        media_type,
        source_code,
        maybe_output_code: None,
        maybe_source_map: None,
      })
    };
    let default_attempt = use_extension("");
    if default_attempt.is_ok() {
      return default_attempt;
    }
    debug!("Trying {}.ts...", module_name);
    let ts_attempt = use_extension(".ts");
    if ts_attempt.is_ok() {
      return ts_attempt;
    }
    debug!("Trying {}.js...", module_name);
    use_extension(".js")
  }

  pub fn code_fetch(
    self: &DenoDir,
    module_specifier: &str,
    containing_file: &str,
  ) -> Result<CodeFetchOutput, DenoError> {
    debug!(
      "code_fetch. module_specifier {} containing_file {}",
      module_specifier, containing_file
    );

    let (module_name, filename) =
      self.resolve_module(module_specifier, containing_file)?;

    let result = self.get_source_code(module_name.as_str(), filename.as_str());
    let out = match result {
      Err(err) => {
        if err.kind() == ErrorKind::NotFound {
          // For NotFound, change the message to something better.
          return Err(DenoError::from(std::io::Error::new(
            std::io::ErrorKind::NotFound,
            format!(
              "Cannot resolve module \"{}\" from \"{}\"",
              module_specifier, containing_file
            ),
          )));
        } else {
          return Err(err);
        }
      }
      Ok(out) => out,
    };

    let result =
      self.load_cache(out.filename.as_str(), out.source_code.as_str());
    match result {
      Err(err) => {
        if err.kind() == std::io::ErrorKind::NotFound {
          Ok(out)
        } else {
          Err(err.into())
        }
      }
      Ok((output_code, source_map)) => Ok(CodeFetchOutput {
        module_name: out.module_name,
        filename: out.filename,
        media_type: out.media_type,
        source_code: out.source_code,
        maybe_output_code: Some(output_code),
        maybe_source_map: Some(source_map),
      }),
    }
  }

  // Prototype: https://github.com/denoland/deno/blob/golang/os.go#L56-L68
  fn src_file_to_url(self: &DenoDir, filename: &str) -> String {
    let filename_path = Path::new(filename);
    if filename_path.starts_with(&self.deps) {
      let (rest, prefix) = if filename_path.starts_with(&self.deps_https) {
        let rest = filename_path.strip_prefix(&self.deps_https).unwrap();
        let prefix = "https://".to_string();
        (rest, prefix)
      } else if filename_path.starts_with(&self.deps_http) {
        let rest = filename_path.strip_prefix(&self.deps_http).unwrap();
        let prefix = "http://".to_string();
        (rest, prefix)
      } else {
        // TODO(kevinkassimo): change this to support other protocols than http
        unimplemented!()
      };
      // Windows doesn't support ":" in filenames, so we represent port using a
      // special string.
      // TODO(ry) This current implementation will break on a URL that has
      // the default port but contains "_PORT" in the path.
      let rest = rest.to_str().unwrap().replacen("_PORT", ":", 1);
      prefix + &rest
    } else {
      String::from(filename)
    }
  }

  // Prototype: https://github.com/denoland/deno/blob/golang/os.go#L70-L98
  // Returns (module name, local filename)
  fn resolve_module(
    self: &DenoDir,
    module_specifier: &str,
    containing_file: &str,
  ) -> Result<(String, String), url::ParseError> {
    let module_name;
    let filename;

    let module_specifier = self.src_file_to_url(module_specifier);
    let containing_file = self.src_file_to_url(containing_file);

    debug!(
      "resolve_module module_specifier {} containing_file {}",
      module_specifier, containing_file
    );

    let j: Url = if containing_file == "."
      || is_remote(&module_specifier)
      || Path::new(&module_specifier).is_absolute()
    {
      parse_local_or_remote(&module_specifier)?
    } else if containing_file.ends_with('/') {
      let r = Url::from_directory_path(&containing_file);
      // TODO(ry) Properly handle error.
      if r.is_err() {
        error!("Url::from_directory_path error {}", containing_file);
      }
      let base = r.unwrap();
      base.join(module_specifier.as_ref())?
    } else {
      let base = parse_local_or_remote(&containing_file)?;
      base.join(module_specifier.as_ref())?
    };

    match j.scheme() {
      "file" => {
        let mut p = deno_fs::normalize_path(j.to_file_path().unwrap().as_ref());
        module_name = p.clone();
        filename = p;
      }
      "https" => {
        module_name = j.to_string();
        filename = deno_fs::normalize_path(
          get_cache_filename(self.deps_https.as_path(), &j).as_ref(),
        )
      }
      "http" => {
        module_name = j.to_string();
        filename = deno_fs::normalize_path(
          get_cache_filename(self.deps_http.as_path(), &j).as_ref(),
        )
      }
      // TODO(kevinkassimo): change this to support other protocols than http
      _ => unimplemented!(),
    }

    debug!("module_name: {}, filename: {}", module_name, filename);
    Ok((module_name, filename))
  }
}

fn get_cache_filename(basedir: &Path, url: &Url) -> PathBuf {
  let host = url.host_str().unwrap();
  let host_port = match url.port() {
    // Windows doesn't support ":" in filenames, so we represent port using a
    // special string.
    Some(port) => format!("{}_PORT{}", host, port),
    None => host.to_string(),
  };

  let mut out = basedir.to_path_buf();
  out.push(host_port);
  for path_seg in url.path_segments().unwrap() {
    out.push(path_seg);
  }
  out
}

#[test]
fn test_get_cache_filename() {
  let url = Url::parse("http://example.com:1234/path/to/file.ts").unwrap();
  let basedir = Path::new("/cache/dir/");
  let cache_file = get_cache_filename(&basedir, &url);
  assert_eq!(
    cache_file,
    Path::new("/cache/dir/example.com_PORT1234/path/to/file.ts")
  );
}

#[derive(Debug)]
pub struct CodeFetchOutput {
  pub module_name: String,
  pub filename: String,
  pub media_type: msg::MediaType,
  pub source_code: String,
  pub maybe_output_code: Option<String>,
  pub maybe_source_map: Option<String>,
}

#[cfg(test)]
pub fn test_setup() -> (TempDir, DenoDir) {
  let temp_dir = TempDir::new().expect("tempdir fail");
  let deno_dir =
    DenoDir::new(false, Some(temp_dir.path())).expect("setup fail");
  (temp_dir, deno_dir)
}

#[test]
fn test_cache_path() {
  let (temp_dir, deno_dir) = test_setup();
  assert_eq!(
    (
      temp_dir
        .path()
        .join("gen/a3e29aece8d35a19bf9da2bb1c086af71fb36ed5.js"),
      temp_dir
        .path()
        .join("gen/a3e29aece8d35a19bf9da2bb1c086af71fb36ed5.js.map")
    ),
    deno_dir.cache_path("hello.ts", "1+2")
  );
}

#[test]
fn test_code_cache() {
  let (_temp_dir, deno_dir) = test_setup();

  let filename = "hello.js";
  let source_code = "1+2";
  let output_code = "1+2 // output code";
  let source_map = "{}";
  let (cache_path, source_map_path) =
    deno_dir.cache_path(filename, source_code);
  assert!(
    cache_path.ends_with("gen/e8e3ee6bee4aef2ec63f6ec3db7fc5fdfae910ae.js")
  );
  assert!(
    source_map_path
      .ends_with("gen/e8e3ee6bee4aef2ec63f6ec3db7fc5fdfae910ae.js.map")
  );

  let r = deno_dir.code_cache(filename, source_code, output_code, source_map);
  r.expect("code_cache error");
  assert!(cache_path.exists());
  assert_eq!(output_code, fs::read_to_string(&cache_path).unwrap());
}

// https://github.com/denoland/deno/blob/golang/deno_dir.go#L25-L30
fn source_code_hash(filename: &str, source_code: &str) -> String {
  let mut ctx = ring::digest::Context::new(&ring::digest::SHA1);
  ctx.update(filename.as_bytes());
  ctx.update(source_code.as_bytes());
  let digest = ctx.finish();
  let mut out = String::new();
  // TODO There must be a better way to do this...
  for byte in digest.as_ref() {
    write!(&mut out, "{:02x}", byte).unwrap();
  }
  out
}

#[test]
fn test_source_code_hash() {
  assert_eq!(
    "a3e29aece8d35a19bf9da2bb1c086af71fb36ed5",
    source_code_hash("hello.ts", "1+2")
  );
  // Different source_code should result in different hash.
  assert_eq!(
    "914352911fc9c85170908ede3df1128d690dda41",
    source_code_hash("hello.ts", "1")
  );
  // Different filename should result in different hash.
  assert_eq!(
    "2e396bc66101ecc642db27507048376d972b1b70",
    source_code_hash("hi.ts", "1+2")
  );
}

// The `add_root` macro prepends "C:" to a string if on windows; on posix
// systems it returns the input string untouched. This is necessary because
// `Url::from_file_path()` fails if the input path isn't an absolute path.
#[cfg(test)]
macro_rules! add_root {
  ($path:expr) => {
    if cfg!(target_os = "windows") {
      concat!("C:", $path)
    } else {
      $path
    }
  };
}

#[test]
fn test_code_fetch() {
  let (_temp_dir, deno_dir) = test_setup();

  let cwd = std::env::current_dir().unwrap();
  let cwd_string = String::from(cwd.to_str().unwrap()) + "/";

  // Test failure case.
  let module_specifier = "hello.ts";
  let containing_file = add_root!("/baddir/badfile.ts");
  let r = deno_dir.code_fetch(module_specifier, containing_file);
  assert!(r.is_err());

  // Assuming cwd is the deno repo root.
  let module_specifier = "./js/main.ts";
  let containing_file = cwd_string.as_str();
  let r = deno_dir.code_fetch(module_specifier, containing_file);
  assert!(r.is_ok());
  //let code_fetch_output = r.unwrap();
  //println!("code_fetch_output {:?}", code_fetch_output);
}

#[test]
fn test_code_fetch_no_ext() {
  let (_temp_dir, deno_dir) = test_setup();

  let cwd = std::env::current_dir().unwrap();
  let cwd_string = String::from(cwd.to_str().unwrap()) + "/";

  // Assuming cwd is the deno repo root.
  let module_specifier = "./js/main";
  let containing_file = cwd_string.as_str();
  let r = deno_dir.code_fetch(module_specifier, containing_file);
  assert!(r.is_ok());

  // Test .ts extension
  // Assuming cwd is the deno repo root.
  let module_specifier = "./js/main";
  let containing_file = cwd_string.as_str();
  let r = deno_dir.code_fetch(module_specifier, containing_file);
  assert!(r.is_ok());
  let code_fetch_output = r.unwrap();
  // could only test .ends_with to avoid include local abs path
  assert!(code_fetch_output.module_name.ends_with("/js/main.ts"));
  assert!(code_fetch_output.filename.ends_with("/js/main.ts"));
  assert!(code_fetch_output.source_code.len() > 10);

  // Test .js extension
  // Assuming cwd is the deno repo root.
  let module_specifier = "./js/mock_builtin";
  let containing_file = cwd_string.as_str();
  let r = deno_dir.code_fetch(module_specifier, containing_file);
  assert!(r.is_ok());
  let code_fetch_output = r.unwrap();
  // could only test .ends_with to avoid include local abs path
  assert!(
    code_fetch_output
      .module_name
      .ends_with("/js/mock_builtin.js")
  );
  assert!(code_fetch_output.filename.ends_with("/js/mock_builtin.js"));
  assert!(code_fetch_output.source_code.len() > 10);
}

#[test]
fn test_src_file_to_url_1() {
  let (_temp_dir, deno_dir) = test_setup();
  assert_eq!("hello", deno_dir.src_file_to_url("hello"));
  assert_eq!("/hello", deno_dir.src_file_to_url("/hello"));
  let x = deno_dir.deps_http.join("hello/world.txt");
  assert_eq!(
    "http://hello/world.txt",
    deno_dir.src_file_to_url(x.to_str().unwrap())
  );
}

#[test]
fn test_src_file_to_url_2() {
  let (_temp_dir, deno_dir) = test_setup();
  assert_eq!("hello", deno_dir.src_file_to_url("hello"));
  assert_eq!("/hello", deno_dir.src_file_to_url("/hello"));
  let x = deno_dir.deps_https.join("hello/world.txt");
  assert_eq!(
    "https://hello/world.txt",
    deno_dir.src_file_to_url(x.to_str().unwrap())
  );
}

#[test]
fn test_src_file_to_url_3() {
  let (_temp_dir, deno_dir) = test_setup();
  let x = deno_dir.deps_http.join("localhost_PORT4545/world.txt");
  assert_eq!(
    "http://localhost:4545/world.txt",
    deno_dir.src_file_to_url(x.to_str().unwrap())
  );
}

#[test]
fn test_src_file_to_url_4() {
  let (_temp_dir, deno_dir) = test_setup();
  let x = deno_dir.deps_https.join("localhost_PORT4545/world.txt");
  assert_eq!(
    "https://localhost:4545/world.txt",
    deno_dir.src_file_to_url(x.to_str().unwrap())
  );
}

// https://github.com/denoland/deno/blob/golang/os_test.go#L16-L87
#[test]
fn test_resolve_module_1() {
  let (_temp_dir, deno_dir) = test_setup();

  let test_cases = [
    (
      "./subdir/print_hello.ts",
      add_root!(
        "/Users/rld/go/src/github.com/denoland/deno/testdata/006_url_imports.ts"
      ),
      add_root!(
        "/Users/rld/go/src/github.com/denoland/deno/testdata/subdir/print_hello.ts"
      ),
      add_root!(
        "/Users/rld/go/src/github.com/denoland/deno/testdata/subdir/print_hello.ts"
      ),
    ),
    (
      "testdata/001_hello.js",
      add_root!("/Users/rld/go/src/github.com/denoland/deno/"),
      add_root!("/Users/rld/go/src/github.com/denoland/deno/testdata/001_hello.js"),
      add_root!("/Users/rld/go/src/github.com/denoland/deno/testdata/001_hello.js"),
    ),
    (
      add_root!("/Users/rld/src/deno/hello.js"),
      ".",
      add_root!("/Users/rld/src/deno/hello.js"),
      add_root!("/Users/rld/src/deno/hello.js"),
    ),
    (
      add_root!("/this/module/got/imported.js"),
      add_root!("/that/module/did/it.js"),
      add_root!("/this/module/got/imported.js"),
      add_root!("/this/module/got/imported.js"),
    ),
  ];
  for &test in test_cases.iter() {
    let module_specifier = String::from(test.0);
    let containing_file = String::from(test.1);
    let (module_name, filename) = deno_dir
      .resolve_module(&module_specifier, &containing_file)
      .unwrap();
    assert_eq!(module_name, test.2);
    assert_eq!(filename, test.3);
  }
}

#[test]
fn test_resolve_module_2() {
  let (_temp_dir, deno_dir) = test_setup();

  let module_specifier = "http://localhost:4545/testdata/subdir/print_hello.ts";
  let containing_file = add_root!("/deno/testdata/006_url_imports.ts");

  let expected_module_name =
    "http://localhost:4545/testdata/subdir/print_hello.ts";
  let expected_filename = deno_fs::normalize_path(
    deno_dir
      .deps_http
      .join("localhost_PORT4545/testdata/subdir/print_hello.ts")
      .as_ref(),
  );

  let (module_name, filename) = deno_dir
    .resolve_module(module_specifier, containing_file)
    .unwrap();
  assert_eq!(module_name, expected_module_name);
  assert_eq!(filename, expected_filename);
}

#[test]
fn test_resolve_module_3() {
  let (_temp_dir, deno_dir) = test_setup();

  let module_specifier_ =
    deno_dir.deps_http.join("unpkg.com/liltest@0.0.5/index.ts");
  let module_specifier = module_specifier_.to_str().unwrap();
  let containing_file = ".";

  let expected_module_name = "http://unpkg.com/liltest@0.0.5/index.ts";
  let expected_filename = deno_fs::normalize_path(
    deno_dir
      .deps_http
      .join("unpkg.com/liltest@0.0.5/index.ts")
      .as_ref(),
  );

  let (module_name, filename) = deno_dir
    .resolve_module(module_specifier, containing_file)
    .unwrap();
  assert_eq!(module_name, expected_module_name);
  assert_eq!(filename, expected_filename);
}

#[test]
fn test_resolve_module_4() {
  let (_temp_dir, deno_dir) = test_setup();

  let module_specifier = "./util";
  let containing_file_ =
    deno_dir.deps_http.join("unpkg.com/liltest@0.0.5/index.ts");
  let containing_file = containing_file_.to_str().unwrap();

  // http containing files -> load relative import with http
  let expected_module_name = "http://unpkg.com/liltest@0.0.5/util";
  let expected_filename = deno_fs::normalize_path(
    deno_dir
      .deps_http
      .join("unpkg.com/liltest@0.0.5/util")
      .as_ref(),
  );

  let (module_name, filename) = deno_dir
    .resolve_module(module_specifier, containing_file)
    .unwrap();
  assert_eq!(module_name, expected_module_name);
  assert_eq!(filename, expected_filename);
}

#[test]
fn test_resolve_module_5() {
  let (_temp_dir, deno_dir) = test_setup();

  let module_specifier = "./util";
  let containing_file_ =
    deno_dir.deps_https.join("unpkg.com/liltest@0.0.5/index.ts");
  let containing_file = containing_file_.to_str().unwrap();

  // https containing files -> load relative import with https
  let expected_module_name = "https://unpkg.com/liltest@0.0.5/util";
  let expected_filename = deno_fs::normalize_path(
    deno_dir
      .deps_https
      .join("unpkg.com/liltest@0.0.5/util")
      .as_ref(),
  );

  let (module_name, filename) = deno_dir
    .resolve_module(module_specifier, containing_file)
    .unwrap();
  assert_eq!(module_name, expected_module_name);
  assert_eq!(filename, expected_filename);
}

#[test]
fn test_resolve_module_6() {
  let (_temp_dir, deno_dir) = test_setup();

  let module_specifier = "http://localhost:4545/tests/subdir/mod2.ts";
  let containing_file = add_root!("/deno/tests/006_url_imports.ts");
  let expected_module_name = "http://localhost:4545/tests/subdir/mod2.ts";
  let expected_filename = deno_fs::normalize_path(
    deno_dir
      .deps_http
      .join("localhost_PORT4545/tests/subdir/mod2.ts")
      .as_ref(),
  );

  let (module_name, filename) = deno_dir
    .resolve_module(module_specifier, containing_file)
    .unwrap();
  assert_eq!(module_name, expected_module_name);
  assert_eq!(filename, expected_filename);
}

const ASSET_PREFIX: &str = "/$asset$/";

fn is_remote(module_name: &str) -> bool {
  module_name.starts_with("http")
}

fn parse_local_or_remote(p: &str) -> Result<url::Url, url::ParseError> {
  if is_remote(p) {
    Url::parse(p)
  } else {
    Url::from_file_path(p).map_err(|_err| url::ParseError::IdnaError)
  }
}

fn map_file_extension(path: &Path) -> msg::MediaType {
  match path.extension() {
    None => msg::MediaType::Unknown,
    Some(os_str) => match os_str.to_str() {
      Some("ts") => msg::MediaType::TypeScript,
      Some("js") => msg::MediaType::JavaScript,
      Some("json") => msg::MediaType::Json,
      _ => msg::MediaType::Unknown,
    },
  }
}

#[test]
fn test_map_file_extension() {
  assert_eq!(
    map_file_extension(Path::new("foo/bar.ts")),
    msg::MediaType::TypeScript
  );
  assert_eq!(
    map_file_extension(Path::new("foo/bar.d.ts")),
    msg::MediaType::TypeScript
  );
  assert_eq!(
    map_file_extension(Path::new("foo/bar.js")),
    msg::MediaType::JavaScript
  );
  assert_eq!(
    map_file_extension(Path::new("foo/bar.json")),
    msg::MediaType::Json
  );
  assert_eq!(
    map_file_extension(Path::new("foo/bar.txt")),
    msg::MediaType::Unknown
  );
  assert_eq!(
    map_file_extension(Path::new("foo/bar")),
    msg::MediaType::Unknown
  );
}

// convert a ContentType string into a enumerated MediaType
fn map_content_type(path: &Path, content_type: Option<&str>) -> msg::MediaType {
  match content_type {
    Some(content_type) => {
      // sometimes there is additional data after the media type in
      // Content-Type so we have to do a bit of manipulation so we are only
      // dealing with the actual media type
      let ct_vector: Vec<&str> = content_type.split(';').collect();
      let ct: &str = ct_vector.first().unwrap();
      match ct.to_lowercase().as_ref() {
        "application/typescript"
        | "text/typescript"
        | "video/vnd.dlna.mpeg-tts"
        | "video/mp2t"
        | "application/x-typescript" => msg::MediaType::TypeScript,
        "application/javascript"
        | "text/javascript"
        | "application/ecmascript"
        | "text/ecmascript"
        | "application/x-javascript" => msg::MediaType::JavaScript,
        "application/json" | "text/json" => msg::MediaType::Json,
        "text/plain" => map_file_extension(path),
        _ => {
          debug!("unknown content type: {}", content_type);
          msg::MediaType::Unknown
        }
      }
    }
    None => map_file_extension(path),
  }
}

#[test]
fn test_map_content_type() {
  // Extension only
  assert_eq!(
    map_content_type(Path::new("foo/bar.ts"), None),
    msg::MediaType::TypeScript
  );
  assert_eq!(
    map_content_type(Path::new("foo/bar.d.ts"), None),
    msg::MediaType::TypeScript
  );
  assert_eq!(
    map_content_type(Path::new("foo/bar.js"), None),
    msg::MediaType::JavaScript
  );
  assert_eq!(
    map_content_type(Path::new("foo/bar.json"), None),
    msg::MediaType::Json
  );
  assert_eq!(
    map_content_type(Path::new("foo/bar.txt"), None),
    msg::MediaType::Unknown
  );
  assert_eq!(
    map_content_type(Path::new("foo/bar"), None),
    msg::MediaType::Unknown
  );

  // Media Type
  assert_eq!(
    map_content_type(Path::new("foo/bar"), Some("application/typescript")),
    msg::MediaType::TypeScript
  );
  assert_eq!(
    map_content_type(Path::new("foo/bar"), Some("text/typescript")),
    msg::MediaType::TypeScript
  );
  assert_eq!(
    map_content_type(Path::new("foo/bar"), Some("video/vnd.dlna.mpeg-tts")),
    msg::MediaType::TypeScript
  );
  assert_eq!(
    map_content_type(Path::new("foo/bar"), Some("video/mp2t")),
    msg::MediaType::TypeScript
  );
  assert_eq!(
    map_content_type(Path::new("foo/bar"), Some("application/x-typescript")),
    msg::MediaType::TypeScript
  );
  assert_eq!(
    map_content_type(Path::new("foo/bar"), Some("application/javascript")),
    msg::MediaType::JavaScript
  );
  assert_eq!(
    map_content_type(Path::new("foo/bar"), Some("text/javascript")),
    msg::MediaType::JavaScript
  );
  assert_eq!(
    map_content_type(Path::new("foo/bar"), Some("application/ecmascript")),
    msg::MediaType::JavaScript
  );
  assert_eq!(
    map_content_type(Path::new("foo/bar"), Some("text/ecmascript")),
    msg::MediaType::JavaScript
  );
  assert_eq!(
    map_content_type(Path::new("foo/bar"), Some("application/x-javascript")),
    msg::MediaType::JavaScript
  );
  assert_eq!(
    map_content_type(Path::new("foo/bar"), Some("application/json")),
    msg::MediaType::Json
  );
  assert_eq!(
    map_content_type(Path::new("foo/bar"), Some("text/json")),
    msg::MediaType::Json
  );
  assert_eq!(
    map_content_type(Path::new("foo/bar.ts"), Some("text/plain")),
    msg::MediaType::TypeScript
  );
  assert_eq!(
    map_content_type(Path::new("foo/bar.ts"), Some("foo/bar")),
    msg::MediaType::Unknown
  );
}