From 493adb4688d445d52e1227eb03dce31d274b3741 Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Sat, 19 Oct 2024 16:15:23 -0400
Subject: [PATCH] Switch to iterative instead of recursive.

---
 src/command/build/runner.rs  | 16 +++++++--
 src/command/build/walk_fs.rs | 66 +++++++++++++++++++++++-------------
 2 files changed, 55 insertions(+), 27 deletions(-)

diff --git a/src/command/build/runner.rs b/src/command/build/runner.rs
index a36c9af..b9fe1b7 100644
--- a/src/command/build/runner.rs
+++ b/src/command/build/runner.rs
@@ -5,6 +5,7 @@ use std::sync::Mutex;
 
 use super::stylesheet::Stylesheet;
 use super::walk_fs::walk_fs;
+use super::walk_fs::WalkAction;
 use crate::cli::parameters::BuildArgs;
 use crate::command::build::render::SiteRenderer;
 use crate::config::Config;
@@ -61,12 +62,21 @@ async fn get_output_directory(config: &Config) -> Result<PathBuf, CustomError> {
     Ok(output_directory)
 }
 
-async fn filter_to_post_directories(entry: &DirEntry) -> Result<bool, CustomError> {
-    Ok(true)
+async fn filter_to_highest_folders_containing_org_files(
+    entry: &DirEntry,
+) -> Result<WalkAction, CustomError> {
+    let file_type = entry.file_type().await?;
+    let mut entries = tokio::fs::read_dir(entry.path()).await?;
+
+    todo!()
 }
 
 async fn get_post_directories(config: &Config) -> Result<Vec<PathBuf>, CustomError> {
-    walk_fs(config.get_posts_directory(), filter_to_post_directories).await?;
+    walk_fs(
+        config.get_posts_directory(),
+        filter_to_highest_folders_containing_org_files,
+    )
+    .await?;
 
     let mut ret = Vec::new();
     if !config.get_posts_directory().exists() {
diff --git a/src/command/build/walk_fs.rs b/src/command/build/walk_fs.rs
index 0361a70..cf20661 100644
--- a/src/command/build/walk_fs.rs
+++ b/src/command/build/walk_fs.rs
@@ -1,35 +1,53 @@
-use std::future::Future;
+use std::collections::VecDeque;
 use std::ops::AsyncFn;
-use std::path::Path;
+use std::path::PathBuf;
 
-use futures::future::BoxFuture;
-use futures::FutureExt;
 use tokio::fs::DirEntry;
 
 use crate::error::CustomError;
 
-pub(crate) fn walk_fs<'p, P: AsRef<Path> + std::marker::Send + 'p>(
+pub(crate) async fn walk_fs<
+    P: Into<PathBuf>,
+    F: AsyncFn(&DirEntry) -> Result<WalkAction, CustomError>,
+>(
     root: P,
-    predicate: impl AsyncFn(&DirEntry) -> Result<bool, CustomError>
-        + std::marker::Send
-        + 'p
-        + std::marker::Copy,
-) -> BoxFuture<'p, Result<Vec<DirEntry>, CustomError>> {
-    async move {
-        let mut ret = Vec::new();
-        let mut entries = tokio::fs::read_dir(root).await?;
+    filter: F,
+) -> Result<Vec<DirEntry>, CustomError> {
+    let mut ret = Vec::new();
+    let mut backlog = VecDeque::new();
+    backlog.push_back(root.into());
+    while let Some(p) = backlog.pop_front() {
+        let mut entries = tokio::fs::read_dir(p).await?;
         while let Some(entry) = entries.next_entry().await? {
-            let file_type = entry.file_type().await?;
-            if file_type.is_dir() {
-                let child_entries = walk_fs(entry.path(), predicate).await?;
-                ret.extend(child_entries);
-            }
-            if predicate(&entry).await? {
-                ret.push(entry);
-            }
+            let action = filter(&entry).await?;
+            match action {
+                WalkAction::HaltAndCapture => {
+                    ret.push(entry);
+                }
+                WalkAction::Halt => {}
+                WalkAction::RecurseAndCapture => {
+                    backlog.push_back(entry.path());
+                    ret.push(entry);
+                }
+                WalkAction::Recurse => {
+                    backlog.push_back(entry.path());
+                }
+            };
         }
-
-        Ok(ret)
     }
-    .boxed()
+    Ok(ret)
+}
+
+pub(crate) enum WalkAction {
+    /// Do not walk down this path but add it to the return list.
+    HaltAndCapture,
+
+    /// Do not walk down this path and do not add it to the return list.
+    Halt,
+
+    /// Walk down this path and add it to the return list.
+    RecurseAndCapture,
+
+    /// Walk down this path but do not add it to the return list.
+    Recurse,
 }