1 files changed, 108 insertions, 0 deletions
diff --git a/src/file/imp/windows.rs b/src/file/imp/windows.rs
new file mode 100644
index 0000000..71b4748
--- /dev/null
+++ b/src/file/imp/windows.rs
@@ -0,0 +1,108 @@
+use std::ffi::OsStr;
+use std::fs::{File, OpenOptions};
+use std::os::windows::ffi::OsStrExt;
+use std::os::windows::fs::OpenOptionsExt;
+use std::os::windows::io::{AsRawHandle, FromRawHandle, RawHandle};
+use std::path::Path;
+use std::{io, iter};
+
+use winapi::um::fileapi::SetFileAttributesW;
+use winapi::um::handleapi::INVALID_HANDLE_VALUE;
+use winapi::um::winbase::{MoveFileExW, ReOpenFile};
+use winapi::um::winbase::{FILE_FLAG_DELETE_ON_CLOSE, MOVEFILE_REPLACE_EXISTING};
+use winapi::um::winnt::{FILE_ATTRIBUTE_NORMAL, FILE_ATTRIBUTE_TEMPORARY};
+use winapi::um::winnt::{FILE_GENERIC_READ, FILE_GENERIC_WRITE, HANDLE};
+use winapi::um::winnt::{FILE_SHARE_DELETE, FILE_SHARE_READ, FILE_SHARE_WRITE};
+
+use crate::util;
+
+fn to_utf16(s: &Path) -> Vec<u16> {
+    s.as_os_str().encode_wide().chain(iter::once(0)).collect()
+}
+
+pub fn create_named(path: &Path, open_options: &mut OpenOptions) -> io::Result<File> {
+    open_options
+        .create_new(true)
+        .read(true)
+        .write(true)
+        .custom_flags(FILE_ATTRIBUTE_TEMPORARY)
+        .open(path)
+}
+
+pub fn create(dir: &Path) -> io::Result<File> {
+    util::create_helper(
+        dir,
+        OsStr::new(".tmp"),
+        OsStr::new(""),
+        crate::NUM_RAND_CHARS,
+        |path| {
+            OpenOptions::new()
+                .create_new(true)
+                .read(true)
+                .write(true)
+                .share_mode(0)
+                .custom_flags(FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_DELETE_ON_CLOSE)
+                .open(path)
+        },
+    )
+}
+
+pub fn reopen(file: &File, _path: &Path) -> io::Result<File> {
+    let handle = file.as_raw_handle();
+    unsafe {
+        let handle = ReOpenFile(
+            handle as HANDLE,
+            FILE_GENERIC_READ | FILE_GENERIC_WRITE,
+            FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+            0,
+        );
+        if handle == INVALID_HANDLE_VALUE {
+            Err(io::Error::last_os_error())
+        } else {
+            Ok(FromRawHandle::from_raw_handle(handle as RawHandle))
+        }
+    }
+}
+
+pub fn keep(path: &Path) -> io::Result<()> {
+    unsafe {
+        let path_w = to_utf16(path);
+        if SetFileAttributesW(path_w.as_ptr(), FILE_ATTRIBUTE_NORMAL) == 0 {
+            Err(io::Error::last_os_error())
+        } else {
+            Ok(())
+        }
+    }
+}
+
+pub fn persist(old_path: &Path, new_path: &Path, overwrite: bool) -> io::Result<()> {
+    // TODO: We should probably do this in one-shot using SetFileInformationByHandle but the API is
+    // really painful.
+
+    unsafe {
+        let old_path_w = to_utf16(old_path);
+        let new_path_w = to_utf16(new_path);
+
+        // Don't succeed if this fails. We don't want to claim to have successfully persisted a file
+        // still marked as temporary because this file won't have the same consistency guarantees.
+        if SetFileAttributesW(old_path_w.as_ptr(), FILE_ATTRIBUTE_NORMAL) == 0 {
+            return Err(io::Error::last_os_error());
+        }
+
+        let mut flags = 0;
+
+        if overwrite {
+            flags |= MOVEFILE_REPLACE_EXISTING;
+        }
+
+        if MoveFileExW(old_path_w.as_ptr(), new_path_w.as_ptr(), flags) == 0 {
+            let e = io::Error::last_os_error();
+            // If this fails, the temporary file is now un-hidden and no longer marked temporary
+            // (slightly less efficient) but it will still work.
+            let _ = SetFileAttributesW(old_path_w.as_ptr(), FILE_ATTRIBUTE_TEMPORARY);
+            Err(e)
+        } else {
+            Ok(())
+        }
+    }
+}