Enable Windows builds

Fixes #32.

.travis.yml

@@ -12,6 +12,9 @@ matrix:
     - os: osx
       rust: stable
       env: TARGET=x86_64-apple-darwin
+    - os: windows
+      rust: stable
+      env: TARGET=x86_64-pc-windows-msvc
     # Minimum Rust supported channel.
     - os: linux
       rust: 1.29.0

README.md

@@ -125,3 +125,17 @@ Licensed under either of
  * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
 
 at your option.
+
+
+## Windows caveats
+
+ Since even the Windows-internal tools such as (but not limited to)
+ - Powershell,
+ - Explorer,
+ - dir,
+
+ are not respecting hardlinks or junction points when determining the
+ size of a directory, it has been decided that diskus will count
+ any such entries multiple times. too. See  
+ https://github.com/sharkdp/diskus/issues/32#issuecomment-532817905 for
+ an example of this behaviour.

src/walk.rs → src/walk/mod.rs

@@ -1,6 +1,5 @@
 use std::collections::HashSet;
 use std::fs;
-use std::os::unix::fs::MetadataExt;
 use std::path::PathBuf;
 use std::thread;
 
@@ -10,7 +9,17 @@ use rayon;
 use rayon::prelude::*;
 
 #[derive(Eq, PartialEq, Hash)]
-struct UniqueID(u64, u64);
+pub struct UniqueID(u64, u64);
+
+#[cfg(target_os = "windows")]
+mod windows;
+#[cfg(target_os = "windows")]
+pub use self::windows::*;
+
+#[cfg(not(target_os = "windows"))]
+mod unix;
+#[cfg(not(target_os = "windows"))]
+pub use self::unix::*;
 
 enum Message {
     SizeEntry(Option<UniqueID>, u64),
@@ -21,14 +30,7 @@ enum Message {
 fn walk(tx: channel::Sender<Message>, entries: &[PathBuf]) {
     entries.into_par_iter().for_each_with(tx, |tx_ref, entry| {
         if let Ok(metadata) = entry.symlink_metadata() {
-            // If the entry has more than one hard link, generate
-            // a unique ID consisting of device and inode in order
-            // not to count this entry twice.
-            let unique_id = if metadata.is_file() && metadata.nlink() > 1 {
-                Some(UniqueID(metadata.dev(), metadata.ino()))
-            } else {
-                None
-            };
+            let unique_id = generate_unique_id(&metadata);
 
             let size = metadata.len();
 

src/walk/unix.rs

@@ -0,0 +1,14 @@
+use std::os::unix::fs::MetadataExt;
+
+use super::UniqueID;
+
+pub fn generate_unique_id(metadata: &std::fs::Metadata) -> Option<UniqueID> {
+    // If the entry has more than one hard link, generate
+    // a unique ID consisting of device and inode in order
+    // not to count this entry twice.
+    if metadata.is_file() && metadata.nlink() > 1 {
+        Some(UniqueID(metadata.dev(), metadata.ino()))
+    } else {
+        None
+    }
+}

src/walk/windows.rs

@@ -0,0 +1,13 @@
+pub fn generate_unique_id(_metadata: &std::fs::Metadata) -> Option<super::UniqueID> {
+    // Since even the Windows-internal tools such as (but not limited to)
+    // - Powershell,
+    // - Explorer,
+    // - dir,
+    // are not respecting hardlinks or junction points when determining the
+    // size of a directory [1], it has been decided that diskus will count
+    // any such entries multiple times. too.
+    //
+    // Footnotes:
+    // [1] https://github.com/sharkdp/diskus/issues/32#issuecomment-532817905
+    None
+}