Pipe filesystem writes in `lightning-persister` through `BufWriter`
[rust-lightning] / lightning-persister / src / util.rs
index 0e3999883fb652a2fe511de8f13278f222ffd71b..f26296794c6858a28fc4aa5bce46055a55657cb6 100644 (file)
@@ -1,21 +1,46 @@
+#[cfg(target_os = "windows")]
+extern crate winapi;
+
 use std::fs;
 use std::path::{Path, PathBuf};
+use std::io::{BufWriter, Write};
 
 #[cfg(not(target_os = "windows"))]
 use std::os::unix::io::AsRawFd;
 
+#[cfg(target_os = "windows")]
+use {
+       std::ffi::OsStr,
+       std::os::windows::ffi::OsStrExt
+};
+
 pub(crate) trait DiskWriteable {
-       fn write_to_file(&self, writer: &mut fs::File) -> Result<(), std::io::Error>;
+       fn write_to_file<W: Write>(&self, writer: &mut W) -> Result<(), std::io::Error>;
 }
 
-pub fn get_full_filepath(filepath: String, filename: String) -> String {
-       let mut path = PathBuf::from(filepath);
-       path.push(filename);
-       path.to_str().unwrap().to_string()
+pub(crate) fn get_full_filepath(mut filepath: PathBuf, filename: String) -> String {
+       filepath.push(filename);
+       filepath.to_str().unwrap().to_string()
+}
+
+#[cfg(target_os = "windows")]
+macro_rules! call {
+       ($e: expr) => (
+               if $e != 0 {
+                       return Ok(())
+               } else {
+                       return Err(std::io::Error::last_os_error())
+               }
+       )
+}
+
+#[cfg(target_os = "windows")]
+fn path_to_windows_str<T: AsRef<OsStr>>(path: T) -> Vec<winapi::shared::ntdef::WCHAR> {
+       path.as_ref().encode_wide().chain(Some(0)).collect()
 }
 
 #[allow(bare_trait_objects)]
-pub(crate) fn write_to_file<D: DiskWriteable>(path: String, filename: String, data: &D) -> std::io::Result<()> {
+pub(crate) fn write_to_file<D: DiskWriteable>(path: PathBuf, filename: String, data: &D) -> std::io::Result<()> {
        fs::create_dir_all(path.clone())?;
        // Do a crazy dance with lots of fsync()s to be overly cautious here...
        // We never want to end up in a state where we've lost the old data, or end up using the
@@ -23,23 +48,41 @@ pub(crate) fn write_to_file<D: DiskWriteable>(path: String, filename: String, da
        // The way to atomically write a file on Unix platforms is:
        // open(tmpname), write(tmpfile), fsync(tmpfile), close(tmpfile), rename(), fsync(dir)
        let filename_with_path = get_full_filepath(path, filename);
-       let tmp_filename = format!("{}.tmp", filename_with_path);
+       let tmp_filename = format!("{}.tmp", filename_with_path.clone());
 
        {
                // Note that going by rust-lang/rust@d602a6b, on MacOS it is only safe to use
                // rust stdlib 1.36 or higher.
-               let mut f = fs::File::create(&tmp_filename)?;
-               data.write_to_file(&mut f)?;
-               f.sync_all()?;
+               let mut buf = BufWriter::new(fs::File::create(&tmp_filename)?);
+               data.write_to_file(&mut buf)?;
+               buf.into_inner()?.sync_all()?;
        }
-       fs::rename(&tmp_filename, &filename_with_path)?;
        // Fsync the parent directory on Unix.
        #[cfg(not(target_os = "windows"))]
        {
+               fs::rename(&tmp_filename, &filename_with_path)?;
                let path = Path::new(&filename_with_path).parent().unwrap();
                let dir_file = fs::OpenOptions::new().read(true).open(path)?;
                unsafe { libc::fsync(dir_file.as_raw_fd()); }
        }
+       #[cfg(target_os = "windows")]
+       {
+               let src = PathBuf::from(tmp_filename.clone());
+               let dst = PathBuf::from(filename_with_path.clone());
+               if Path::new(&filename_with_path.clone()).exists() {
+                       unsafe {winapi::um::winbase::ReplaceFileW(
+                               path_to_windows_str(dst).as_ptr(), path_to_windows_str(src).as_ptr(), std::ptr::null(),
+                               winapi::um::winbase::REPLACEFILE_IGNORE_MERGE_ERRORS,
+                               std::ptr::null_mut() as *mut winapi::ctypes::c_void,
+                               std::ptr::null_mut() as *mut winapi::ctypes::c_void
+                       )};
+               } else {
+                       call!(unsafe {winapi::um::winbase::MoveFileExW(
+                               path_to_windows_str(src).as_ptr(), path_to_windows_str(dst).as_ptr(),
+                               winapi::um::winbase::MOVEFILE_WRITE_THROUGH | winapi::um::winbase::MOVEFILE_REPLACE_EXISTING
+                       )});
+               }
+       }
        Ok(())
 }
 
@@ -49,10 +92,11 @@ mod tests {
        use std::fs;
        use std::io;
        use std::io::Write;
+       use std::path::PathBuf;
 
        struct TestWriteable{}
        impl DiskWriteable for TestWriteable {
-               fn write_to_file(&self, writer: &mut fs::File) -> Result<(), io::Error> {
+               fn write_to_file<W: Write>(&self, writer: &mut W) -> Result<(), io::Error> {
                        writer.write_all(&[42; 1])
                }
        }
@@ -70,7 +114,7 @@ mod tests {
                let mut perms = fs::metadata(path.to_string()).unwrap().permissions();
                perms.set_readonly(true);
                fs::set_permissions(path.to_string(), perms).unwrap();
-               match write_to_file(path.to_string(), filename, &test_writeable) {
+               match write_to_file(PathBuf::from(path.to_string()), filename, &test_writeable) {
                        Err(e) => assert_eq!(e.kind(), io::ErrorKind::PermissionDenied),
                        _ => panic!("Unexpected error message")
                }
@@ -79,25 +123,21 @@ mod tests {
        // Test failure to rename in the process of atomically creating a channel
        // monitor's file. We induce this failure by making the `tmp` file a
        // directory.
-       // Explanation: given "from" = the file being renamed, "to" = the
-       // renamee that already exists: Windows should fail because it'll fail
-       // whenever "to" is a directory, and Unix should fail because if "from" is a
-       // file, then "to" is also required to be a file.
+       // Explanation: given "from" = the file being renamed, "to" = the destination
+       // file that already exists: Unix should fail because if "from" is a file,
+       // then "to" is also required to be a file.
+       // TODO: ideally try to make this work on Windows again
+       #[cfg(not(target_os = "windows"))]
        #[test]
        fn test_rename_failure() {
                let test_writeable = TestWriteable{};
                let filename = "test_rename_failure_filename";
-               let path = "test_rename_failure_dir";
+               let path = PathBuf::from("test_rename_failure_dir");
                // Create the channel data file and make it a directory.
-               fs::create_dir_all(get_full_filepath(path.to_string(), filename.to_string())).unwrap();
-               match write_to_file(path.to_string(), filename.to_string(), &test_writeable) {
-                       Err(e) => {
-                               #[cfg(not(target_os = "windows"))]
-                               assert_eq!(e.kind(), io::ErrorKind::Other);
-                               #[cfg(target_os = "windows")]
-                               assert_eq!(e.kind(), io::ErrorKind::PermissionDenied);
-                       }
-                       _ => panic!("Unexpected error message")
+               fs::create_dir_all(get_full_filepath(path.clone(), filename.to_string())).unwrap();
+               match write_to_file(path.clone(), filename.to_string(), &test_writeable) {
+                       Err(e) => assert_eq!(e.raw_os_error(), Some(libc::EISDIR)),
+                       _ => panic!("Unexpected Ok(())")
                }
                fs::remove_dir_all(path).unwrap();
        }
@@ -106,15 +146,15 @@ mod tests {
        fn test_diskwriteable_failure() {
                struct FailingWriteable {}
                impl DiskWriteable for FailingWriteable {
-                       fn write_to_file(&self, _writer: &mut fs::File) -> Result<(), std::io::Error> {
+                       fn write_to_file<W: Write>(&self, _writer: &mut W) -> Result<(), std::io::Error> {
                                Err(std::io::Error::new(std::io::ErrorKind::Other, "expected failure"))
                        }
                }
 
                let filename = "test_diskwriteable_failure";
-               let path = "test_diskwriteable_failure_dir";
+               let path = PathBuf::from("test_diskwriteable_failure_dir");
                let test_writeable = FailingWriteable{};
-               match write_to_file(path.to_string(), filename.to_string(), &test_writeable) {
+               match write_to_file(path.clone(), filename.to_string(), &test_writeable) {
                        Err(e) => {
                                assert_eq!(e.kind(), std::io::ErrorKind::Other);
                                assert_eq!(e.get_ref().unwrap().to_string(), "expected failure");
@@ -131,7 +171,7 @@ mod tests {
        fn test_tmp_file_creation_failure() {
                let test_writeable = TestWriteable{};
                let filename = "test_tmp_file_creation_failure_filename".to_string();
-               let path = "test_tmp_file_creation_failure_dir".to_string();
+               let path = PathBuf::from("test_tmp_file_creation_failure_dir");
 
                // Create the tmp file and make it a directory.
                let tmp_path = get_full_filepath(path.clone(), format!("{}.tmp", filename.clone()));
@@ -139,7 +179,7 @@ mod tests {
                match write_to_file(path, filename, &test_writeable) {
                        Err(e) => {
                                #[cfg(not(target_os = "windows"))]
-                               assert_eq!(e.kind(), io::ErrorKind::Other);
+                               assert_eq!(e.raw_os_error(), Some(libc::EISDIR));
                                #[cfg(target_os = "windows")]
                                assert_eq!(e.kind(), io::ErrorKind::PermissionDenied);
                        }