Replace std::env::home_dir() with home crate impl.

* Import the `home` crate in `util/dir`.

* Replace uses of `env::home_dir()` with `home::home_dir()`.
  * `home` uses a 'correct' impl. on windows and the stdlib impl.
    of `::home_dir` otherwise.

* Reexport `home::home_dir` from `util/dir`.

* Bump `util/dir` to 0.1.2.

parity/upgrade.rs

@@ -19,11 +19,10 @@
 use semver::{Version, SemVerError};
 use std::collections::*;
 use std::fs::{self, File, create_dir_all};
-use std::env;
 use std::io;
 use std::io::{Read, Write};
 use std::path::{PathBuf, Path};
-use dir::{DatabaseDirectories, default_data_path};
+use dir::{DatabaseDirectories, default_data_path, home_dir};
 use dir::helpers::replace_home;
 use journaldb::Algorithm;
 
@@ -201,7 +200,7 @@ fn upgrade_user_defaults(dirs: &DatabaseDirectories) {
 }
 
 pub fn upgrade_data_paths(base_path: &str, dirs: &DatabaseDirectories, pruning: Algorithm) {
-	if env::home_dir().is_none() {
+	if home_dir().is_none() {
 		return;
 	}
 

util/dir/Cargo.toml

@@ -1,10 +1,11 @@
 [package]
 name = "dir"
-version = "0.1.1"
+version = "0.1.2"
 authors = ["Parity Technologies <admin@parity.io>"]
 license = "GPL3"
 
 [dependencies]
 ethereum-types = "0.3"
 journaldb = { path = "../journaldb" }
 app_dirs = { git = "https://github.com/paritytech/app-dirs-rs" }
+home = "0.3"

util/dir/src/helpers.rs

@@ -15,14 +15,14 @@
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
 //! Directory helper functions
-use std::env;
+use ::home_dir;
 
 /// Replaces `$HOME` str with home directory path.
 pub fn replace_home(base: &str, arg: &str) -> String {
 	// the $HOME directory on mac os should be `~/Library` or `~/Library/Application Support`
 	// We use an `if` so that we don't need to call `home_dir()` if not necessary.
 	let r = if arg.contains("$HOME") {
-		arg.replace("$HOME", env::home_dir().expect("$HOME isn't defined").to_str().unwrap())
+		arg.replace("$HOME", home_dir().expect("$HOME isn't defined").to_str().unwrap())
 	} else {
 		arg.to_owned()
 	};