From 72af75c035e6ae459914654c654243b435ace255 Mon Sep 17 00:00:00 2001
From: Lars Wirzenius <liw@liw.fi>
Date: Mon, 1 Oct 2018 17:24:50 +0300
Subject: Change: split out fswaslking to its own module

---
 src/fswalk.rs | 117 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)
 create mode 100644 src/fswalk.rs

diff --git a/src/fswalk.rs b/src/fswalk.rs
new file mode 100644
index 0000000..ac95540
--- /dev/null
+++ b/src/fswalk.rs
@@ -0,0 +1,117 @@
+use std::io;
+use std::path::PathBuf;
+use std::cmp::Ordering;
+
+// A filesystem entry: directory, file, symlink, etc
+#[derive(Debug)]
+pub struct Entry {
+    path: PathBuf,
+}
+
+impl Entry {
+    fn new(path: &PathBuf) -> Entry {
+        Entry {
+            path: path.clone(),
+        }
+    }
+
+    pub fn path(&self) -> String {
+        self.path.to_string_lossy().to_string()
+    }
+}
+
+impl Eq for Entry {}
+
+impl PartialEq for Entry {
+    fn eq(&self, other: &Entry) -> bool {
+        self.path == other.path
+    }
+}
+
+impl Ord for Entry {
+    fn cmp(&self, other: &Entry) -> Ordering {
+        self.path.cmp(&other.path)
+    }
+}
+
+impl PartialOrd for Entry {
+    fn partial_cmp(&self, other: &Entry) -> Option<Ordering> {
+        Some(self.path.cmp(&other.path))
+    }
+}
+
+// Keep two stacks of Entry values, sorted in ascending order. The
+// first stack has non-directories. When we iterate, we return a
+// directory, then of its non-dirs, then recurse each of its subdirs.
+#[derive(Debug)]
+pub struct DirTree {
+    entries: Vec<Entry>,
+    dirs: Vec<Entry>,
+}
+
+impl DirTree {
+    pub fn new(path: &str) -> DirTree {
+        let mut dt = DirTree::empty();
+        dt.add_dir(&PathBuf::from(path));
+        dt
+    }
+
+    fn empty() -> DirTree {
+        DirTree {
+            entries: Vec::new(),
+            dirs: Vec::new(),
+        }
+    }
+
+    fn add_dir(&mut self, path: &PathBuf) {
+        let entry = Entry::new(path);
+        self.dirs.push(entry);
+    }
+
+    fn add_entries(&mut self, path: &PathBuf) -> io::Result<()> {
+        let mut entries = Vec::new();
+        let mut dirs = Vec::new();
+        for dir_entry in path.read_dir()? {
+            let dir_entry = dir_entry?;
+            let metadata = dir_entry.metadata()?;
+            let entry = Entry::new(&dir_entry.path());
+            if metadata.is_dir() {
+                dirs.push(entry);
+            } else {
+                entries.push(entry);
+            }
+        }
+
+        entries.sort();
+        entries.reverse();
+        for e in entries {
+            self.entries.push(e);
+        }
+
+        dirs.sort();
+        dirs.reverse();
+        for e in dirs {
+            self.dirs.push(e);
+        }
+
+        Ok(())
+    }
+}
+
+impl Iterator for DirTree {
+    type Item = Entry;
+
+    fn next(&mut self) -> Option<Entry> {
+        if let Some(e) = self.entries.pop() {
+            Some(e)
+        } else if let Some(e) = self.dirs.pop() {
+            if let Ok(_) = self.add_entries(&e.path) {
+                // We ignore any errors from adding entries. Boo. Not
+                // sure how I'd propagate errors, from a next method.
+            }
+            Some(e)
+        } else {
+            None
+        }
+    }
+}
-- 
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