Move mmap to storages from example

crates/librqbit/src/storage/mmap.rs

@@ -0,0 +1,60 @@
+use anyhow::Context;
+use memmap2::{MmapMut, MmapOptions};
+use parking_lot::RwLock;
+
+use crate::{FileInfos, ManagedTorrentInfo};
+
+use super::{StorageFactory, TorrentStorage};
+
+pub struct MmapStorageFactory {}
+
+struct MmapStorage {
+    mmap: RwLock<MmapMut>,
+    file_infos: FileInfos,
+}
+
+impl StorageFactory for MmapStorageFactory {
+    fn init_storage(
+        &self,
+        info: &ManagedTorrentInfo,
+    ) -> anyhow::Result<Box<dyn crate::storage::TorrentStorage>> {
+        Ok(Box::new(MmapStorage {
+            mmap: RwLock::new(
+                MmapOptions::new()
+                    .len(info.lengths.total_length().try_into()?)
+                    .map_anon()?,
+            ),
+            file_infos: info.file_infos.clone(),
+        }))
+    }
+}
+
+impl TorrentStorage for MmapStorage {
+    fn pread_exact(&self, file_id: usize, offset: u64, buf: &mut [u8]) -> anyhow::Result<()> {
+        let start: usize = (self.file_infos[file_id].offset_in_torrent + offset).try_into()?;
+        let end = start + buf.len();
+        buf.copy_from_slice(self.mmap.read().get(start..end).context("bad range")?);
+        Ok(())
+    }
+
+    fn pwrite_all(&self, file_id: usize, offset: u64, buf: &[u8]) -> anyhow::Result<()> {
+        let start: usize = (self.file_infos[file_id].offset_in_torrent + offset).try_into()?;
+        let end = start + buf.len();
+        let mut g = self.mmap.write();
+        let target = g.get_mut(start..end).context("bad range")?;
+        target.copy_from_slice(buf);
+        Ok(())
+    }
+
+    fn remove_file(&self, _file_id: usize, _filename: &std::path::Path) -> anyhow::Result<()> {
+        Ok(())
+    }
+
+    fn ensure_file_length(&self, _file_id: usize, _length: u64) -> anyhow::Result<()> {
+        Ok(())
+    }
+
+    fn take(&self) -> anyhow::Result<Box<dyn TorrentStorage>> {
+        anyhow::bail!("not implemented")
+    }
+}

crates/librqbit/src/storage/mod.rs

@@ -1,5 +1,6 @@
 pub mod example;
 pub mod filesystem;
+pub mod mmap;
 
 use std::{any::Any, path::Path};