313 lines
9.8 KiB
Rust
313 lines
9.8 KiB
Rust
//! Simple file-locking apis for each OS.
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//!
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//! This is not meant to be in the standard library, it does nothing with
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//! green/native threading. This is just a bare-bones enough solution for
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//! librustdoc, it is not production quality at all.
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#![allow(non_camel_case_types)]
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#![allow(nonstandard_style)]
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use std::io;
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use std::path::Path;
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cfg_if! {
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if #[cfg(unix)] {
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use std::ffi::{CString, OsStr};
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use std::os::unix::prelude::*;
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#[cfg(any(target_os = "linux", target_os = "android"))]
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mod os {
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#[repr(C)]
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pub struct flock {
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pub l_type: libc::c_short,
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pub l_whence: libc::c_short,
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pub l_start: libc::off_t,
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pub l_len: libc::off_t,
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pub l_pid: libc::pid_t,
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// not actually here, but brings in line with freebsd
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pub l_sysid: libc::c_int,
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}
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}
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#[cfg(target_os = "freebsd")]
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mod os {
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#[repr(C)]
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pub struct flock {
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pub l_start: libc::off_t,
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pub l_len: libc::off_t,
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pub l_pid: libc::pid_t,
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pub l_type: libc::c_short,
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pub l_whence: libc::c_short,
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pub l_sysid: libc::c_int,
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}
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}
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#[cfg(any(target_os = "dragonfly",
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target_os = "bitrig",
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target_os = "netbsd",
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target_os = "openbsd"))]
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mod os {
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#[repr(C)]
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pub struct flock {
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pub l_start: libc::off_t,
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pub l_len: libc::off_t,
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pub l_pid: libc::pid_t,
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pub l_type: libc::c_short,
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pub l_whence: libc::c_short,
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// not actually here, but brings in line with freebsd
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pub l_sysid: libc::c_int,
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}
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}
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#[cfg(target_os = "haiku")]
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mod os {
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#[repr(C)]
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pub struct flock {
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pub l_type: libc::c_short,
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pub l_whence: libc::c_short,
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pub l_start: libc::off_t,
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pub l_len: libc::off_t,
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pub l_pid: libc::pid_t,
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// not actually here, but brings in line with freebsd
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pub l_sysid: libc::c_int,
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}
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}
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#[cfg(any(target_os = "macos", target_os = "ios"))]
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mod os {
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#[repr(C)]
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pub struct flock {
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pub l_start: libc::off_t,
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pub l_len: libc::off_t,
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pub l_pid: libc::pid_t,
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pub l_type: libc::c_short,
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pub l_whence: libc::c_short,
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// not actually here, but brings in line with freebsd
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pub l_sysid: libc::c_int,
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}
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}
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#[cfg(target_os = "solaris")]
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mod os {
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#[repr(C)]
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pub struct flock {
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pub l_type: libc::c_short,
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pub l_whence: libc::c_short,
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pub l_start: libc::off_t,
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pub l_len: libc::off_t,
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pub l_sysid: libc::c_int,
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pub l_pid: libc::pid_t,
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}
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}
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#[derive(Debug)]
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pub struct Lock {
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fd: libc::c_int,
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}
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impl Lock {
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pub fn new(p: &Path,
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wait: bool,
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create: bool,
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exclusive: bool)
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-> io::Result<Lock> {
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let os: &OsStr = p.as_ref();
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let buf = CString::new(os.as_bytes()).unwrap();
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let open_flags = if create {
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libc::O_RDWR | libc::O_CREAT
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} else {
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libc::O_RDWR
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};
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let fd = unsafe {
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libc::open(buf.as_ptr(), open_flags,
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libc::S_IRWXU as libc::c_int)
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};
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if fd < 0 {
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return Err(io::Error::last_os_error());
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}
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let lock_type = if exclusive {
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libc::F_WRLCK as libc::c_short
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} else {
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libc::F_RDLCK as libc::c_short
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};
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let flock = os::flock {
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l_start: 0,
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l_len: 0,
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l_pid: 0,
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l_whence: libc::SEEK_SET as libc::c_short,
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l_type: lock_type,
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l_sysid: 0,
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};
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let cmd = if wait { libc::F_SETLKW } else { libc::F_SETLK };
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let ret = unsafe {
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libc::fcntl(fd, cmd, &flock)
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};
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if ret == -1 {
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let err = io::Error::last_os_error();
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unsafe { libc::close(fd); }
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Err(err)
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} else {
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Ok(Lock { fd })
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}
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}
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}
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impl Drop for Lock {
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fn drop(&mut self) {
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let flock = os::flock {
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l_start: 0,
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l_len: 0,
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l_pid: 0,
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l_whence: libc::SEEK_SET as libc::c_short,
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l_type: libc::F_UNLCK as libc::c_short,
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l_sysid: 0,
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};
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unsafe {
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libc::fcntl(self.fd, libc::F_SETLK, &flock);
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libc::close(self.fd);
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}
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}
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}
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} else if #[cfg(windows)] {
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use std::mem;
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use std::os::windows::prelude::*;
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use std::os::windows::raw::HANDLE;
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use std::fs::{File, OpenOptions};
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use std::os::raw::{c_ulong, c_int};
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type DWORD = c_ulong;
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type BOOL = c_int;
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type ULONG_PTR = usize;
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type LPOVERLAPPED = *mut OVERLAPPED;
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const LOCKFILE_EXCLUSIVE_LOCK: DWORD = 0x0000_0002;
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const LOCKFILE_FAIL_IMMEDIATELY: DWORD = 0x0000_0001;
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const FILE_SHARE_DELETE: DWORD = 0x4;
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const FILE_SHARE_READ: DWORD = 0x1;
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const FILE_SHARE_WRITE: DWORD = 0x2;
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#[repr(C)]
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struct OVERLAPPED {
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Internal: ULONG_PTR,
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InternalHigh: ULONG_PTR,
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Offset: DWORD,
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OffsetHigh: DWORD,
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hEvent: HANDLE,
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}
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extern "system" {
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fn LockFileEx(hFile: HANDLE,
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dwFlags: DWORD,
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dwReserved: DWORD,
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nNumberOfBytesToLockLow: DWORD,
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nNumberOfBytesToLockHigh: DWORD,
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lpOverlapped: LPOVERLAPPED) -> BOOL;
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}
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#[derive(Debug)]
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pub struct Lock {
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_file: File,
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}
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impl Lock {
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pub fn new(p: &Path,
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wait: bool,
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create: bool,
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exclusive: bool)
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-> io::Result<Lock> {
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assert!(p.parent().unwrap().exists(),
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"Parent directory of lock-file must exist: {}",
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p.display());
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let share_mode = FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE;
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let mut open_options = OpenOptions::new();
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open_options.read(true)
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.share_mode(share_mode);
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if create {
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open_options.create(true)
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.write(true);
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}
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debug!("Attempting to open lock file `{}`", p.display());
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let file = match open_options.open(p) {
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Ok(file) => {
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debug!("Lock file opened successfully");
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file
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}
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Err(err) => {
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debug!("Error opening lock file: {}", err);
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return Err(err)
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}
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};
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let ret = unsafe {
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let mut overlapped: OVERLAPPED = mem::zeroed();
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let mut dwFlags = 0;
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if !wait {
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dwFlags |= LOCKFILE_FAIL_IMMEDIATELY;
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}
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if exclusive {
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dwFlags |= LOCKFILE_EXCLUSIVE_LOCK;
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}
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debug!("Attempting to acquire lock on lock file `{}`",
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p.display());
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LockFileEx(file.as_raw_handle(),
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dwFlags,
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0,
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0xFFFF_FFFF,
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0xFFFF_FFFF,
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&mut overlapped)
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};
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if ret == 0 {
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let err = io::Error::last_os_error();
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debug!("Failed acquiring file lock: {}", err);
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Err(err)
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} else {
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debug!("Successfully acquired lock.");
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Ok(Lock { _file: file })
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}
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}
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}
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// Note that we don't need a Drop impl on the Windows: The file is unlocked
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// automatically when it's closed.
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} else {
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#[derive(Debug)]
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pub struct Lock(());
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impl Lock {
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pub fn new(_p: &Path, _wait: bool, _create: bool, _exclusive: bool)
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-> io::Result<Lock>
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{
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let msg = "file locks not supported on this platform";
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Err(io::Error::new(io::ErrorKind::Other, msg))
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}
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}
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}
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}
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impl Lock {
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pub fn panicking_new(p: &Path,
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wait: bool,
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create: bool,
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exclusive: bool)
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-> Lock {
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Lock::new(p, wait, create, exclusive).unwrap_or_else(|err| {
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panic!("could not lock `{}`: {}", p.display(), err);
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})
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}
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}
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