From 6b8000d8fd8b88afbc7fb45094da29fb02627ed2 Mon Sep 17 00:00:00 2001
From: Determinant <tederminant@gmail.com>
Date: Tue, 16 Jun 2020 12:40:07 -0400
Subject: finish the AIO File/Store impl

---
 src/lib.rs | 169 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 169 insertions(+)

(limited to 'src')

diff --git a/src/lib.rs b/src/lib.rs
index 7635dab..906ec41 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,2 +1,171 @@
 #[macro_use] extern crate scan_fmt;
 pub mod wal;
+
+use async_trait::async_trait;
+use futures::executor::block_on;
+use libaiofut::{new_batch_scheduler, AIOBatchSchedulerIn, AIOManager};
+use libc::off_t;
+use nix::fcntl::{fallocate, open, openat, FallocateFlags, OFlag};
+use nix::sys::stat::Mode;
+use nix::unistd::{close, ftruncate, mkdir, unlinkat, UnlinkatFlags};
+use std::cell::RefCell;
+use std::os::unix::io::RawFd;
+use std::rc::Rc;
+use wal::{WALBytes, WALFile, WALPos, WALRingId, WALStore};
+
+pub struct WALFileAIO {
+    fd: RawFd,
+    aiomgr: Rc<RefCell<AIOManager<AIOBatchSchedulerIn>>>,
+}
+
+impl WALFileAIO {
+    pub fn new(
+        rootfd: RawFd,
+        filename: &str,
+        aiomgr: Rc<RefCell<AIOManager<AIOBatchSchedulerIn>>>,
+    ) -> Result<Self, ()> {
+        openat(
+            rootfd,
+            filename,
+            OFlag::O_CREAT | OFlag::O_RDWR,
+            Mode::S_IRUSR | Mode::S_IWUSR,
+        )
+        .and_then(|fd| Ok(WALFileAIO { fd, aiomgr }))
+        .or_else(|_| Err(()))
+    }
+}
+
+impl Drop for WALFileAIO {
+    fn drop(&mut self) {
+        close(self.fd).unwrap();
+    }
+}
+
+#[async_trait(?Send)]
+impl WALFile for WALFileAIO {
+    async fn allocate(&self, offset: WALPos, length: usize) -> Result<(), ()> {
+        // TODO: is there any async version of fallocate?
+        fallocate(
+            self.fd,
+            FallocateFlags::FALLOC_FL_ZERO_RANGE,
+            offset as off_t,
+            length as off_t,
+        )
+        .and_then(|_| Ok(()))
+        .or_else(|_| Err(()))
+    }
+
+    fn truncate(&self, length: usize) -> Result<(), ()> {
+        ftruncate(self.fd, length as off_t).or_else(|_| Err(()))
+    }
+
+    async fn write(&self, offset: WALPos, data: WALBytes) -> Result<(), ()> {
+        self.aiomgr
+            .borrow_mut()
+            .write(self.fd, offset, data, None)
+            .await
+            .or_else(|_| Err(()))
+            .and_then(|(nwrote, data)| {
+                if nwrote == data.len() {
+                    Ok(())
+                } else {
+                    Err(())
+                }
+            })
+    }
+
+    fn read(
+        &self,
+        offset: WALPos,
+        length: usize,
+    ) -> Result<Option<WALBytes>, ()> {
+        block_on(self.aiomgr.borrow_mut().read(self.fd, offset, length, None))
+            .or_else(|_| Err(()))
+            .and_then(|(nread, data)| {
+                Ok(if nread == length { Some(data) } else { None })
+            })
+    }
+}
+
+pub struct WALStoreAIO<F: FnMut(WALBytes, WALRingId) -> Result<(), ()>> {
+    rootfd: RawFd,
+    rootpath: String,
+    recover_func: RefCell<F>,
+}
+
+impl<F: FnMut(WALBytes, WALRingId) -> Result<(), ()>> WALStoreAIO<F> {
+    pub fn new(wal_dir: &str, truncate: bool, recover_func: F) -> Self {
+        let recover_func = RefCell::new(recover_func);
+        let rootpath = wal_dir.to_string();
+        if truncate {
+            let _ = std::fs::remove_dir_all(wal_dir);
+        }
+        match mkdir(wal_dir, Mode::S_IRUSR | Mode::S_IWUSR | Mode::S_IXUSR) {
+            Err(e) => {
+                if truncate {
+                    panic!("error while creating directory: {}", e)
+                }
+            }
+            Ok(_) => (),
+        }
+        let rootfd = match open(
+            wal_dir,
+            OFlag::O_DIRECTORY | OFlag::O_PATH,
+            Mode::empty(),
+        ) {
+            Ok(fd) => fd,
+            Err(_) => panic!("error while opening the WAL directory"),
+        };
+        WALStoreAIO {
+            rootfd,
+            rootpath,
+            recover_func,
+        }
+    }
+}
+
+#[async_trait(?Send)]
+impl<F: FnMut(WALBytes, WALRingId) -> Result<(), ()>> WALStore
+    for WALStoreAIO<F>
+{
+    type FileNameIter = std::vec::IntoIter<String>;
+
+    async fn open_file(
+        &self,
+        filename: &str,
+        _touch: bool,
+    ) -> Result<Box<dyn WALFile>, ()> {
+        let filename = filename.to_string();
+        let aiomgr = Rc::new(RefCell::new(
+            AIOManager::new(new_batch_scheduler(None), 10, None, None)
+                .or(Err(()))?,
+        ));
+        WALFileAIO::new(self.rootfd, &filename, aiomgr.clone())
+            .and_then(|f| Ok(Box::new(f) as Box<dyn WALFile>))
+    }
+
+    async fn remove_file(&self, filename: String) -> Result<(), ()> {
+        unlinkat(
+            Some(self.rootfd),
+            filename.as_str(),
+            UnlinkatFlags::NoRemoveDir,
+        )
+        .or_else(|_| Err(()))
+    }
+
+    fn enumerate_files(&self) -> Result<Self::FileNameIter, ()> {
+        let mut logfiles = Vec::new();
+        for fname in std::fs::read_dir(&self.rootpath).unwrap() {
+            logfiles.push(fname.unwrap().file_name().into_string().unwrap())
+        }
+        Ok(logfiles.into_iter())
+    }
+
+    fn apply_payload(
+        &self,
+        payload: WALBytes,
+        ringid: WALRingId,
+    ) -> Result<(), ()> {
+        (&mut *self.recover_func.borrow_mut())(payload, ringid)
+    }
+}
-- 
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