From 60f831bc6f47dafdeba1edcc1692ae534312adbd Mon Sep 17 00:00:00 2001
From: Igor Katson <igor.katson@gmail.com>
Date: Mon, 19 Aug 2024 11:25:45 +0100
Subject: [PATCH] dummy file is Option now instead of additional open

---
 crates/librqbit/src/storage/filesystem/fs.rs  | 30 +++++++++++++++----
 .../librqbit/src/storage/filesystem/mmap.rs   |  3 +-
 .../src/storage/filesystem/opened_file.rs     | 23 +++-----------
 3 files changed, 30 insertions(+), 26 deletions(-)

diff --git a/crates/librqbit/src/storage/filesystem/fs.rs b/crates/librqbit/src/storage/filesystem/fs.rs
index 4831a76..5d202b0 100644
--- a/crates/librqbit/src/storage/filesystem/fs.rs
+++ b/crates/librqbit/src/storage/filesystem/fs.rs
@@ -54,7 +54,12 @@ impl TorrentStorage for FilesystemStorage {
         #[cfg(target_family = "unix")]
         {
             use std::os::unix::fs::FileExt;
-            Ok(of.file.read().read_exact_at(buf, offset)?)
+            Ok(of
+                .file
+                .read()
+                .as_ref()
+                .context("file is None")?
+                .read_exact_at(buf, offset)?)
         }
         #[cfg(not(target_family = "unix"))]
         {
@@ -70,14 +75,21 @@ impl TorrentStorage for FilesystemStorage {
         #[cfg(target_family = "unix")]
         {
             use std::os::unix::fs::FileExt;
-            Ok(of.file.read().write_all_at(buf, offset)?)
+            Ok(of
+                .file
+                .read()
+                .as_ref()
+                .context("file is None")?
+                .write_all_at(buf, offset)?)
         }
         #[cfg(target_family = "windows")]
         {
             use std::os::windows::fs::FileExt;
             let mut remaining = buf.len();
+            let g = of.file.read();
+            let f = g.as_ref().context("file is None")?;
             while remaining > 0 {
-                remaining -= of.file.read().seek_write(buf, offset)?;
+                remaining -= f.seek_write(buf, offset)?;
             }
             Ok(())
         }
@@ -85,8 +97,9 @@ impl TorrentStorage for FilesystemStorage {
         {
             use std::io::{Read, Seek, SeekFrom, Write};
             let mut g = of.file.write();
-            g.seek(SeekFrom::Start(offset))?;
-            Ok(g.write_all(buf)?)
+            let mut f = g.as_ref().context("file is None")?;
+            f.seek(SeekFrom::Start(offset))?;
+            Ok(f.write_all(buf)?)
         }
     }
 
@@ -95,7 +108,12 @@ impl TorrentStorage for FilesystemStorage {
     }
 
     fn ensure_file_length(&self, file_id: usize, len: u64) -> anyhow::Result<()> {
-        Ok(self.opened_files[file_id].file.write().set_len(len)?)
+        Ok(self.opened_files[file_id]
+            .file
+            .write()
+            .as_ref()
+            .context("file is None")?
+            .set_len(len)?)
     }
 
     fn take(&self) -> anyhow::Result<Box<dyn TorrentStorage>> {
diff --git a/crates/librqbit/src/storage/filesystem/mmap.rs b/crates/librqbit/src/storage/filesystem/mmap.rs
index 07efe1e..1e68b24 100644
--- a/crates/librqbit/src/storage/filesystem/mmap.rs
+++ b/crates/librqbit/src/storage/filesystem/mmap.rs
@@ -102,9 +102,10 @@ impl TorrentStorage for MmapFilesystemStorage {
         let mut mmaps = Vec::new();
         for (idx, file) in self.fs.opened_files.iter().enumerate() {
             let fg = file.file.write();
+            let fg = fg.as_ref().context("file is None")?;
             fg.set_len(meta.file_infos[idx].len)
                 .context("mmap storage: error setting length")?;
-            let mmap = unsafe { MmapOptions::new().map_mut(&*fg) }.context("error mapping file")?;
+            let mmap = unsafe { MmapOptions::new().map_mut(fg) }.context("error mapping file")?;
             mmaps.push(RwLock::new(mmap));
         }
 
diff --git a/crates/librqbit/src/storage/filesystem/opened_file.rs b/crates/librqbit/src/storage/filesystem/opened_file.rs
index 88f24dd..f1f4e06 100644
--- a/crates/librqbit/src/storage/filesystem/opened_file.rs
+++ b/crates/librqbit/src/storage/filesystem/opened_file.rs
@@ -1,37 +1,22 @@
 use std::fs::File;
 
-use anyhow::Context;
 use parking_lot::RwLock;
 
 #[derive(Debug)]
 pub(crate) struct OpenedFile {
-    pub file: RwLock<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))
+    pub file: RwLock<Option<File>>,
 }
 
 impl OpenedFile {
     pub fn new(f: File) -> Self {
         Self {
-            file: RwLock::new(f),
+            file: RwLock::new(Some(f)),
         }
     }
 
-    pub fn take(&self) -> anyhow::Result<File> {
+    pub fn take(&self) -> anyhow::Result<Option<File>> {
         let mut f = self.file.write();
-        let dummy = dummy_file()?;
-        let f = std::mem::replace(&mut *f, dummy);
-        Ok(f)
+        Ok(f.take())
     }
 
     pub fn take_clone(&self) -> anyhow::Result<Self> {