Refactor DenoDir (#2636)

* rename `ModuleMetaData` to `SourceFile` and remove TS specific
  functionality

* add `TsCompiler` struct encapsulating processing of TypeScript files

* move `SourceMapGetter` trait implementation to `//cli/compiler.rs`

* add low-level `DiskCache` API for general purpose caches and use it in
  `DenoDir` and `TsCompiler` for filesystem access

* don't use hash-like filenames for compiled modules, instead use
  metadata file for storing compilation hash

* add `SourceFileCache` for in-process caching of loaded files for fast
  subsequent access

* define `SourceFileFetcher` trait encapsulating loading of local and
  remote files and implement it for `DenoDir`

* define `use_cache` and `no_fetch` flags on `DenoDir` instead of using
  in fetch methods

1 files changed, 29 insertions, 0 deletions

diff --git a/cli/fs.rs b/cli/fs.rs
index 6fe891141..34e4d59f2 100644
--- a/cli/fs.rs
+++ b/cli/fs.rs
@@ -8,6 +8,7 @@ use std::path::{Path, PathBuf};
 use deno::ErrBox;
 use rand;
 use rand::Rng;
+use url::Url;
 
 #[cfg(unix)]
 use nix::unistd::{chown as unix_chown, Gid, Uid};
@@ -126,3 +127,31 @@ pub fn chown(_path: &str, _uid: u32, _gid: u32) -> Result<(), ErrBox> {
   // TODO: implement chown for Windows
   Err(crate::deno_error::op_not_implemented())
 }
+
+pub fn resolve_from_cwd(path: &str) -> Result<(PathBuf, String), ErrBox> {
+  let candidate_path = Path::new(path);
+
+  let resolved_path = if candidate_path.is_absolute() {
+    candidate_path.to_owned()
+  } else {
+    let cwd = std::env::current_dir().unwrap();
+    cwd.join(path)
+  };
+
+  // HACK: `Url::from_directory_path` is used here because it normalizes the path.
+  // Joining `/dev/deno/" with "./tests" using `PathBuf` yields `/deno/dev/./tests/`.
+  // On the other hand joining `/dev/deno/" with "./tests" using `Url` yields "/dev/deno/tests"
+  // - and that's what we want.
+  // There exists similar method on `PathBuf` - `PathBuf.canonicalize`, but the problem
+  // is `canonicalize` resolves symlinks and we don't want that.
+  // We just want o normalize the path...
+  let resolved_url = Url::from_file_path(resolved_path)
+    .expect("PathBuf should be parseable URL");
+  let normalized_path = resolved_url
+    .to_file_path()
+    .expect("URL from PathBuf should be valid path");
+
+  let path_string = normalized_path.to_str().unwrap().to_string();
+
+  Ok((normalized_path, path_string))
+}