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Use locking open flags if they are defined

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This commit is contained in:
LeRoyce Pearson 2020-03-23 20:59:09 -06:00
parent 613956cc47
commit 5b278fb606
1 changed files with 23 additions and 12 deletions
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35
lib/std/fs.zig
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@ -666,8 +666,19 @@ pub const Dir = struct {
const path_w = try os.windows.cStrToPrefixedFileW(sub_path);
return self.openFileW(&path_w, flags);
}
// Use the O_ locking flags if the os supports them
const lock_flag: u32 = lock_flag: {
if (!flags.lock) break :lock_flag 0;
if (flags.write) {
break :lock_flag if (@hasDecl(os, "O_EXLOCK")) os.O_EXLOCK else 0;
} else {
break :lock_flag if (@hasDecl(os, "O_SHLOCK")) os.O_SHLOCK else 0;
}
};
const O_LARGEFILE = if (@hasDecl(os, "O_LARGEFILE")) os.O_LARGEFILE else 0;
const os_flags = O_LARGEFILE | os.O_CLOEXEC | if (flags.write and flags.read)
const os_flags = lock_flag | O_LARGEFILE | os.O_CLOEXEC | if (flags.write and flags.read)
@as(u32, os.O_RDWR)
else if (flags.write)
@as(u32, os.O_WRONLY)
@ -678,18 +689,14 @@ pub const Dir = struct {
else
try os.openatC(self.fd, sub_path, os_flags, 0);
var locked = false;
if (flags.lock) {
// use fcntl file locking if no lock flag was given
if (flags.lock and lock_flag == 0) {
// TODO: integrate async I/O
// mem.zeroes is used here because flock's structure can vary across architectures and systems
var flock = mem.zeroes(os.Flock);
flock.l_type = if (flags.write) os.F_WRLCK else os.F_RDLCK;
flock.l_whence = os.SEEK_SET;
flock.l_start = 0;
flock.l_len = 0;
flock.l_pid = 0;
try os.fcntl(fd, os.F_SETLKW, &flock);
locked = true;
}
return File{
@ -735,8 +742,15 @@ pub const Dir = struct {
const path_w = try os.windows.cStrToPrefixedFileW(sub_path_c);
return self.createFileW(&path_w, flags);
}
// Use the O_ locking flags if the os supports them
const lock_flag: u32 = lock_flag: {
if (!flags.lock) break :lock_flag 0;
break :lock_flag if (@hasDecl(os, "O_EXLOCK")) os.O_EXLOCK else 0;
};
const O_LARGEFILE = if (@hasDecl(os, "O_LARGEFILE")) os.O_LARGEFILE else 0;
const os_flags = O_LARGEFILE | os.O_CREAT | os.O_CLOEXEC |
const os_flags = lock_flag | O_LARGEFILE | os.O_CREAT | os.O_CLOEXEC |
(if (flags.truncate) @as(u32, os.O_TRUNC) else 0) |
(if (flags.read) @as(u32, os.O_RDWR) else os.O_WRONLY) |
(if (flags.exclusive) @as(u32, os.O_EXCL) else 0);
@ -745,15 +759,12 @@ pub const Dir = struct {
else
try os.openatC(self.fd, sub_path_c, os_flags, flags.mode);
if (flags.lock) {
if (flags.lock and lock_flag == 0) {
// TODO: integrate async I/O
// mem.zeroes is used here because flock's structure can vary across architectures and systems
var flock = mem.zeroes(os.Flock);
flock.l_type = os.F_WRLCK;
flock.l_whence = os.SEEK_SET;
flock.l_start = 0;
flock.l_len = 0;
flock.l_pid = 0;
try os.fcntl(fd, os.F_SETLKW, &flock);
}