basic wal with registry

Cargo.toml

@@ -11,11 +11,12 @@ members = [
   "libsql-replication",
   "libsql-ffi",
   "libsql-hrana",
+  "libsql-wal",
 
   "vendored/rusqlite",
   "vendored/sqlite3-parser",
 
-  "xtask", "libsql-hrana",
+  "xtask", "libsql-hrana", "libsql-wal",
 ]
 
 exclude = [

libsql-wal/Cargo.toml

@@ -0,0 +1,25 @@
+[package]
+name = "libsql-wal"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+bytes = "1.6.0"
+fst = "0.4.7"
+hashbrown = "0.14.3"
+libsql-sys = { path = "../libsql-sys", features = ["rusqlite"] }
+memmap = "0.7.0"
+memoffset = "0.9.1"
+mmap = "0.1.1"
+nix = { version = "0.28.0", features = ["uio", "fs"] }
+parking_lot = "0.12.1"
+tokio = { version = "1.36.0", features = ["full"] }
+tracing = "0.1.40"
+tracing-subscriber = { version = "0.3.18", features = ["env-filter", "time"] }
+walkdir = "2.5.0"
+zerocopy = { version = "0.7.32", features = ["derive"] }
+
+[dev-dependencies]
+tempfile = "3.10.1"

libsql-wal/src/file.rs

@@ -0,0 +1,73 @@
+use std::io;
+use std::io::ErrorKind;
+use std::io::IoSlice;
+use std::io::Result;
+
+use std::fs::File;
+use std::io::Write;
+
+pub trait FileExt {
+    fn write_all_at(&self, buf: &[u8], offset: u64) -> Result<()>;
+    fn write_at_vectored(&self, bufs: &[IoSlice], offset: u64) -> Result<usize>;
+    fn write_at(&self, buf: &[u8], offset: u64) -> Result<usize>;
+
+    fn read_exact_at(&self, buf: &mut [u8], offset: u64) -> Result<()>;
+
+    fn cursor(&self, offset: u64) -> Cursor<Self> where Self: Sized {
+        Cursor { file: self, offset }
+    }
+}
+
+impl FileExt for File {
+    fn write_all_at(&self, buf: &[u8], offset: u64) -> Result<()> {
+        let mut written = 0;
+
+        while written != buf.len() {
+            written += nix::sys::uio::pwrite(self, &buf[written..], offset as _)?;
+        }
+
+        Ok(())
+    }
+
+    fn write_at_vectored(&self, bufs: &[IoSlice], offset: u64) -> Result<usize> {
+        Ok(nix::sys::uio::pwritev(self, bufs, offset as _)?)
+    }
+
+
+    fn write_at(&self, buf: &[u8], offset: u64) -> Result<usize> {
+        Ok(nix::sys::uio::pwrite(self, buf, offset as _)?)
+    }
+
+    fn read_exact_at(&self, buf: &mut [u8], offset: u64) -> Result<()> {
+        let mut read = 0;
+
+        while read != buf.len() {
+            let n = nix::sys::uio::pread(self, &mut buf[read..], (offset + read as u64) as _)?;
+            if n == 0 {
+                return Err(io::Error::new(ErrorKind::UnexpectedEof, "unexpected end-of-file"))
+            }
+            read += n;
+
+        }
+
+        Ok(())
+    }
+}
+
+pub struct Cursor<'a, T> {
+    file: &'a T,
+    offset: u64,
+}
+
+impl<'a, T: FileExt> Write for Cursor<'a, T> {
+    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+        let count = self.file.write_at(buf, self.offset)?;
+        self.offset += count as u64;
+        Ok(count)
+    }
+
+    fn flush(&mut self) -> std::io::Result<()> {
+        Ok(())
+    }
+}
+

libsql-wal/src/lib.rs

@@ -0,0 +1,8 @@
+pub mod shared_wal;
+pub mod log;
+pub mod segment;
+pub mod file;
+pub mod wal;
+pub mod transaction;
+pub mod registry;
+pub mod name;