Desktop: Use the OS temp directory for CEF caches (#4030)

* Desktop: Use the OS temp dir

* Review

desktop/src/dirs.rs

@@ -1,11 +1,31 @@
-use std::fs::create_dir_all;
-use std::path::PathBuf;
+use std::fs;
+use std::io;
+use std::path::{Path, PathBuf};
 
 use crate::consts::{APP_DIRECTORY_NAME, APP_DOCUMENTS_DIRECTORY_NAME};
 
 pub(crate) fn ensure_dir_exists(path: &PathBuf) {
 	if !path.exists() {
-		create_dir_all(path).unwrap_or_else(|_| panic!("Failed to create directory at {path:?}"));
+		fs::create_dir_all(path).unwrap_or_else(|_| panic!("Failed to create directory at {path:?}"));
+	}
+}
+
+fn clear_dir(path: &PathBuf) {
+	let Ok(entries) = fs::read_dir(path) else {
+		tracing::error!("Failed to read directory at {path:?}");
+		return;
+	};
+	for entry in entries.flatten() {
+		let entry_path = entry.path();
+		if entry_path.is_dir() {
+			if let Err(e) = fs::remove_dir_all(&entry_path) {
+				tracing::error!("Failed to remove directory at {:?}: {}", entry_path, e);
+			}
+		} else if entry_path.is_file() {
+			if let Err(e) = fs::remove_file(&entry_path) {
+				tracing::error!("Failed to remove file at {:?}: {}", entry_path, e);
+			}
+		}
 	}
 }
 
@@ -15,8 +35,52 @@ pub(crate) fn app_data_dir() -> PathBuf {
 	path
 }
 
+fn app_tmp_dir() -> PathBuf {
+	let path = std::env::temp_dir().join(APP_DIRECTORY_NAME);
+	ensure_dir_exists(&path);
+	path
+}
+
+pub(crate) fn app_tmp_dir_cleanup() {
+	clear_dir(&app_tmp_dir());
+}
+
 pub(crate) fn app_autosave_documents_dir() -> PathBuf {
 	let path = app_data_dir().join(APP_DOCUMENTS_DIRECTORY_NAME);
 	ensure_dir_exists(&path);
 	path
 }
+
+/// Temporary directory that is automatically deleted when dropped.
+pub struct TempDir {
+	path: PathBuf,
+}
+
+impl TempDir {
+	pub fn new() -> io::Result<Self> {
+		Self::new_with_parent(app_tmp_dir())
+	}
+
+	pub fn new_with_parent(parent: impl AsRef<Path>) -> io::Result<Self> {
+		let random_suffix = format!("{:032x}", rand::random::<u128>());
+		let name = format!("{}_{}", std::process::id(), random_suffix);
+		let path = parent.as_ref().join(name);
+		fs::create_dir_all(&path)?;
+		Ok(Self { path })
+	}
+}
+
+impl Drop for TempDir {
+	fn drop(&mut self) {
+		let result = fs::remove_dir_all(&self.path);
+		if let Err(e) = result {
+			tracing::error!("Failed to remove temporary directory at {:?}: {}", self.path, e);
+		}
+	}
+}
+
+impl AsRef<Path> for TempDir {
+	fn as_ref(&self) -> &Path {
+		&self.path
+	}
+}