fix: atomically write files to $DENO_DIR (#8822)

cli/disk_cache.rs

@@ -139,7 +139,7 @@ impl DiskCache {
       Some(ref parent) => self.ensure_dir_exists(parent),
       None => Ok(()),
     }?;
-    fs_util::write_file(&path, data, crate::http_cache::CACHE_PERM)
+    fs_util::atomic_write_file(&path, data, crate::http_cache::CACHE_PERM)
       .map_err(|e| with_io_context(&e, format!("{:#?}", &path)))
   }
 }

cli/fs_util.rs

@@ -2,12 +2,28 @@
 
 use deno_core::error::AnyError;
 pub use deno_core::normalize_path;
+use deno_runtime::deno_crypto::rand;
 use std::env::current_dir;
 use std::fs::OpenOptions;
 use std::io::{Error, Write};
 use std::path::{Path, PathBuf};
 use walkdir::WalkDir;
 
+pub fn atomic_write_file<T: AsRef<[u8]>>(
+  filename: &Path,
+  data: T,
+  mode: u32,
+) -> std::io::Result<()> {
+  let rand: String = (0..4)
+    .map(|_| format!("{:02x}", rand::random::<u8>()))
+    .collect();
+  let extension = format!("{}.tmp", rand);
+  let tmp_file = filename.with_extension(extension);
+  write_file(&tmp_file, data, mode)?;
+  std::fs::rename(tmp_file, filename)?;
+  Ok(())
+}
+
 pub fn write_file<T: AsRef<[u8]>>(
   filename: &Path,
   data: T,

cli/http_cache.rs

@@ -87,7 +87,7 @@ impl Metadata {
   pub fn write(&self, cache_filename: &Path) -> Result<(), AnyError> {
     let metadata_filename = Self::filename(cache_filename);
     let json = serde_json::to_string_pretty(self)?;
-    fs_util::write_file(&metadata_filename, json, CACHE_PERM)?;
+    fs_util::atomic_write_file(&metadata_filename, json, CACHE_PERM)?;
     Ok(())
   }
 
@@ -161,7 +161,7 @@ impl HttpCache {
       .expect("Cache filename should have a parent dir");
     self.ensure_dir_exists(parent_filename)?;
     // Cache content
-    fs_util::write_file(&cache_filename, content, CACHE_PERM)?;
+    fs_util::atomic_write_file(&cache_filename, content, CACHE_PERM)?;
 
     let metadata = Metadata {
       url: url.to_string(),