From ecf71d5daef7be88e66f82c075f4438a83c2433a Mon Sep 17 00:00:00 2001
From: Julio Biason <julio.biason@pm.me>
Date: Sat, 16 Sep 2023 15:25:30 -0300
Subject: [PATCH] Working with iter

---
 diritertest/Cargo.lock     |  7 ++++++
 diritertest/Cargo.toml     |  8 +++++++
 diritertest/README.md      |  3 +++
 diritertest/src/diriter.rs | 48 ++++++++++++++++++++++++++++++++++++++
 diritertest/src/main.rs    | 21 +++++++++++++++++
 5 files changed, 87 insertions(+)
 create mode 100644 diritertest/Cargo.lock
 create mode 100644 diritertest/Cargo.toml
 create mode 100644 diritertest/README.md
 create mode 100644 diritertest/src/diriter.rs
 create mode 100644 diritertest/src/main.rs

diff --git a/diritertest/Cargo.lock b/diritertest/Cargo.lock
new file mode 100644
index 0000000..84e82c9
--- /dev/null
+++ b/diritertest/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "diritertest"
+version = "0.1.0"
diff --git a/diritertest/Cargo.toml b/diritertest/Cargo.toml
new file mode 100644
index 0000000..108236b
--- /dev/null
+++ b/diritertest/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "diritertest"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/diritertest/README.md b/diritertest/README.md
new file mode 100644
index 0000000..414d934
--- /dev/null
+++ b/diritertest/README.md
@@ -0,0 +1,3 @@
+# DirIterTest
+
+An iterator over directories (and subdirectories).
diff --git a/diritertest/src/diriter.rs b/diritertest/src/diriter.rs
new file mode 100644
index 0000000..0944ded
--- /dev/null
+++ b/diritertest/src/diriter.rs
@@ -0,0 +1,48 @@
+//! Iterator over directories
+
+use std::collections::VecDeque;
+use std::fs::DirEntry;
+use std::fs::ReadDir;
+use std::path::Path;
+use std::path::PathBuf;
+
+pub struct DirIter {
+    curr_dir: ReadDir,
+    remaining_dirs: VecDeque<PathBuf>,
+}
+
+impl DirIter {
+    pub fn new(start: &Path) -> std::io::Result<Self> {
+        Ok(Self {
+            curr_dir: start.read_dir()?,
+            remaining_dirs: VecDeque::new(),
+        })
+    }
+
+    pub fn advance(&mut self) -> Option<PathBuf> {
+        let next = self.curr_dir.next();
+        match next {
+            Some(Ok(x)) => {
+                if x.path().is_dir() {
+                    self.remaining_dirs.push_back(x.path());
+                    self.advance()
+                } else {
+                    Some(x.path())
+                }
+            }
+            Some(Err(_)) | None => {
+                let next_dir = self.remaining_dirs.pop_front()?;
+                self.curr_dir = std::fs::read_dir(next_dir).ok()?;
+                self.advance()
+            }
+        }
+    }
+}
+
+impl Iterator for DirIter {
+    type Item = PathBuf;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.advance()
+    }
+}
diff --git a/diritertest/src/main.rs b/diritertest/src/main.rs
new file mode 100644
index 0000000..8d11a0b
--- /dev/null
+++ b/diritertest/src/main.rs
@@ -0,0 +1,21 @@
+use std::path::Path;
+
+use crate::diriter::DirIter;
+
+mod diriter;
+
+fn main() {
+    let mut all_iter = DirIter::new(&Path::new(".")).unwrap();
+    while let Some(path) = all_iter.next() {
+        println!(">> {:?}", path);
+    }
+
+    println!("-----------------------");
+
+    let all_iter = DirIter::new(&Path::new(".")).unwrap();
+    for path in all_iter {
+        println!(">>> {:?}", path);
+    }
+
+    println!("Hello, world!");
+}