Move files around a bit

crates/librqbit/src/storage/filesystem/mod.rs

@@ -1,3 +1,5 @@
+mod opened_file;
+
 use std::{
     fs::OpenOptions,
     io::{Read, Seek, SeekFrom, Write},
@@ -6,7 +8,9 @@ use std::{
 
 use anyhow::Context;
 
-use crate::{opened_file::OpenedFile, torrent_state::ManagedTorrentInfo};
+use crate::torrent_state::ManagedTorrentInfo;
+
+use self::opened_file::OpenedFile;
 
 use super::{StorageFactory, TorrentStorage};
 

crates/librqbit/src/storage/filesystem/opened_file.rs

@@ -0,0 +1,43 @@
+use std::fs::File;
+
+use anyhow::Context;
+use parking_lot::Mutex;
+
+#[derive(Debug)]
+pub(crate) struct OpenedFile {
+    pub file: Mutex<File>,
+}
+
+pub(crate) fn dummy_file() -> anyhow::Result<std::fs::File> {
+    #[cfg(target_os = "windows")]
+    const DEVNULL: &str = "NUL";
+    #[cfg(not(target_os = "windows"))]
+    const DEVNULL: &str = "/dev/null";
+
+    std::fs::OpenOptions::new()
+        .read(true)
+        .open(DEVNULL)
+        .with_context(|| format!("error opening {}", DEVNULL))
+}
+
+impl OpenedFile {
+    pub fn new(f: File) -> Self {
+        Self {
+            file: Mutex::new(f),
+        }
+    }
+
+    pub fn take(&self) -> anyhow::Result<File> {
+        let mut f = self.file.lock();
+        let dummy = dummy_file()?;
+        let f = std::mem::replace(&mut *f, dummy);
+        Ok(f)
+    }
+
+    pub fn take_clone(&self) -> anyhow::Result<Self> {
+        let f = self.take()?;
+        Ok(Self {
+            file: Mutex::new(f),
+        })
+    }
+}