fix regression (#8)

Cargo.toml

@@ -14,6 +14,6 @@ random-access-storage = "0.3.0"
 mkdirp = "0.1.0"
 
 [dev-dependencies]
-clippy = "0.0"
+# clippy = "0.0"
 quickcheck = "0.6.2"
 tempdir = "0.3.7"

src/lib.rs

@@ -2,8 +2,8 @@
 #![cfg_attr(test, deny(warnings))]
 #![feature(external_doc)]
 #![doc(include = "../README.md")]
-#![cfg_attr(test, feature(plugin))]
-#![cfg_attr(test, plugin(clippy))]
+// #![cfg_attr(test, feature(plugin))]
+// #![cfg_attr(test, plugin(clippy))]
 
 #[macro_use]
 extern crate failure;

src/sync.rs

@@ -6,14 +6,15 @@ use failure::Error;
 use std::fs;
 use std::fs::OpenOptions;
 use std::io::{Read, Seek, SeekFrom, Write};
+use std::ops::Drop;
 use std::path;
 
 /// Main constructor.
 pub struct Sync {}
 
 impl Sync {
   /// Create a new instance.
-  #[cfg_attr(test, allow(new_ret_no_self))]
+  // #[cfg_attr(test, allow(new_ret_no_self))]
   pub fn new(filename: path::PathBuf) -> random_access::Sync<SyncMethods> {
     random_access::Sync::new(SyncMethods {
       filename,
@@ -26,6 +27,7 @@ impl Sync {
 /// Methods that have been implemented to provide synchronous access to disk.  .
 /// These should generally be kept private, but exposed to prevent leaking
 /// internals.
+#[derive(Debug)]
 pub struct SyncMethods {
   filename: path::PathBuf,
   file: Option<fs::File>,
@@ -37,12 +39,14 @@ impl random_access::SyncMethods for SyncMethods {
     if let Some(dirname) = self.filename.parent() {
       mkdirp::mkdirp(&dirname)?;
     }
-
-    self.file = Some(OpenOptions::new()
-      .create_new(true)
+    let file = OpenOptions::new()
+      .create(true)
       .read(true)
       .write(true)
-      .open(&self.filename)?);
+      .open(&self.filename)?;
+    file.sync_all()?;
+
+    self.file = Some(file);
 
     let metadata = fs::metadata(&self.filename)?;
     self.length = metadata.len();
@@ -53,6 +57,7 @@ impl random_access::SyncMethods for SyncMethods {
     let mut file = self.file.as_ref().expect("self.file was None.");
     file.seek(SeekFrom::Start(offset as u64))?;
     file.write_all(&data)?;
+    file.sync_all()?;
 
     // We've changed the length of our file.
     let new_len = (offset + data.len()) as u64;
@@ -70,7 +75,7 @@ impl random_access::SyncMethods for SyncMethods {
   // whether it's okay to return a fully zero'd out slice. It's a bit weird,
   // because we're replacing empty data with actual zeroes - which does not
   // reflect the state of the world.
-  #[cfg_attr(test, allow(unused_io_amount))]
+  // #[cfg_attr(test, allow(unused_io_amount))]
   fn read(&mut self, offset: usize, length: usize) -> Result<Vec<u8>, Error> {
     ensure!(
       (offset + length) as u64 <= self.length,
@@ -87,3 +92,11 @@ impl random_access::SyncMethods for SyncMethods {
     panic!("Not implemented yet");
   }
 }
+
+impl Drop for SyncMethods {
+  fn drop(&mut self) {
+    if let Some(file) = &self.file {
+      file.sync_all().unwrap();
+    }
+  }
+}

tests/sync_regression.rs

@@ -2,6 +2,7 @@ extern crate random_access_disk as rad;
 extern crate tempdir;
 
 use self::tempdir::TempDir;
+use std::env;
 
 #[test]
 // postmortem: read_exact wasn't behaving like we hoped, so we had to switch
@@ -12,3 +13,15 @@ fn regress_1() {
   file.write(27, b"").unwrap();
   file.read(13, 5).unwrap();
 }
+
+#[test]
+// postmortem: accessing the same file twice would fail, so we had to switch to
+// from `.create_new()` to `.create()`.
+//
+// NOTE: test needs to be run twice in a row to trigger regression. I'm sorry.
+fn regress_2() {
+  let mut dir = env::temp_dir();
+  dir.push("regression-2.db");
+  let mut file = rad::Sync::new(dir);
+  file.write(27, b"").unwrap();
+}