Normalize paths in Windows (fix #113)

While `//?/C:/Users/Someone/config-files` is a valid path, it's not very human friendly.
Such paths are returned from `BaseDirs`. This patch formats them in the traditional way.

src/steps/git.rs

@@ -1,7 +1,7 @@
 use crate::error::Error;
 use crate::executor::{CommandExt, RunType};
 use crate::terminal::print_separator;
-use crate::utils::which;
+use crate::utils::{which, HumanizedPath};
 use log::{debug, error};
 use std::collections::HashSet;
 use std::io;
@@ -58,7 +58,7 @@ impl Git {
     pub fn pull<P: AsRef<Path>>(&self, path: P, run_type: RunType) -> Option<(String, bool)> {
         let path = path.as_ref();
 
-        print_separator(format!("Pulling {}", path.display()));
+        print_separator(format!("Pulling {}", HumanizedPath::from(path)));
 
         let git = self.git.as_ref().unwrap();
 
@@ -73,7 +73,7 @@ impl Git {
         }()
         .is_ok();
 
-        Some((format!("git: {}", path.display()), success))
+        Some((format!("git: {}", HumanizedPath::from(path)), success))
     }
 }
 

src/utils.rs

@@ -1,8 +1,8 @@
 use super::error::{Error, ErrorKind};
 use log::{debug, error};
 use std::ffi::OsStr;
-use std::fmt::Debug;
-use std::path::{Path, PathBuf};
+use std::fmt::{self, Debug};
+use std::path::{Component, Path, PathBuf};
 use std::process::{ExitStatus, Output};
 use which_crate;
 
@@ -68,3 +68,58 @@ pub fn which<T: AsRef<OsStr> + Debug>(binary_name: T) -> Option<PathBuf> {
         }
     }
 }
+
+/// `std::fmt::Display` implementation for `std::path::Path`.
+///
+/// This struct differs from `std::path::Display` in that in Windows it takes care of printing slashes
+/// instead of backslashes and don't print the `\\?` prefix in long paths.
+pub struct HumanizedPath<'a> {
+    path: &'a Path,
+}
+
+impl<'a> From<&'a Path> for HumanizedPath<'a> {
+    fn from(path: &'a Path) -> Self {
+        Self { path }
+    }
+}
+
+impl<'a> fmt::Display for HumanizedPath<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        if cfg!(windows) {
+            let mut iterator = self.path.components().peekable();
+
+            while let Some(component) = iterator.next() {
+                let is_prefix = if let Component::RootDir = &component {
+                    true
+                } else {
+                    false
+                };
+
+                let printed = match &component {
+                    Component::Normal(c) if *c == "?" => false,
+                    Component::RootDir | Component::CurDir => false,
+                    Component::ParentDir => {
+                        write!(f, "..")?;
+                        true
+                    }
+                    Component::Prefix(p) => {
+                        write!(f, "{}", p.as_os_str().to_string_lossy())?;
+                        true
+                    }
+                    Component::Normal(c) => {
+                        write!(f, "{}", c.to_string_lossy())?;
+                        true
+                    }
+                };
+
+                if printed && (iterator.peek().is_some() || is_prefix) {
+                    write!(f, "{}", std::path::MAIN_SEPARATOR)?;
+                }
+            }
+        } else {
+            write!(f, "{}", self.path.display())?;
+        }
+
+        Ok(())
+    }
+}