diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs
index 1af6157ca68bf..4a9405905dc32 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -253,6 +253,7 @@
#![feature(const_ip)]
#![feature(const_ipv4)]
#![feature(const_ipv6)]
+#![feature(const_option)]
#![feature(const_raw_ptr_deref)]
#![feature(const_socketaddr)]
#![feature(container_error_extra)]
diff --git a/library/std/src/sys/windows/args.rs b/library/std/src/sys/windows/args.rs
index f1264130faf7a..3919025b08006 100644
--- a/library/std/src/sys/windows/args.rs
+++ b/library/std/src/sys/windows/args.rs
@@ -1,13 +1,18 @@
-#![allow(dead_code)] // runtime init functions not used during testing
+//! The Windows command line is just a string
+//! <https://docs.microsoft.com/en-us/archive/blogs/larryosterman/the-windows-command-line-is-just-a-string>
+//!
+//! This module implements the parsing necessary to turn that string into a list of arguments.
#[cfg(test)]
mod tests;
use crate::ffi::OsString;
use crate::fmt;
+use crate::marker::PhantomData;
+use crate::num::NonZeroU16;
use crate::os::windows::prelude::*;
use crate::path::PathBuf;
-use crate::slice;
+use crate::ptr::NonNull;
use crate::sys::c;
use crate::sys::windows::os::current_exe;
use crate::vec;
@@ -15,9 +20,11 @@ use crate::vec;
use core::iter;
pub fn args() -> Args {
+ // SAFETY: `GetCommandLineW` returns a pointer to a null terminated UTF-16
+ // string so it's safe for `WStrUnits` to use.
unsafe {
let lp_cmd_line = c::GetCommandLineW();
- let parsed_args_list = parse_lp_cmd_line(lp_cmd_line as *const u16, || {
+ let parsed_args_list = parse_lp_cmd_line(WStrUnits::new(lp_cmd_line), || {
current_exe().map(PathBuf::into_os_string).unwrap_or_else(|_| OsString::new())
});
@@ -28,129 +35,120 @@ pub fn args() -> Args {
/// Implements the Windows command-line argument parsing algorithm.
///
/// Microsoft's documentation for the Windows CLI argument format can be found at
-/// <https://docs.microsoft.com/en-us/previous-versions//17w5ykft(v=vs.85)>.
+/// <https://docs.microsoft.com/en-us/cpp/cpp/main-function-command-line-args?view=msvc-160#parsing-c-command-line-arguments>
///
-/// Windows includes a function to do this in shell32.dll,
-/// but linking with that DLL causes the process to be registered as a GUI application.
+/// A more in-depth explanation is here:
+/// <https://daviddeley.com/autohotkey/parameters/parameters.htm#WIN>
+///
+/// Windows includes a function to do command line parsing in shell32.dll.
+/// However, this is not used for two reasons:
+///
+/// 1. Linking with that DLL causes the process to be registered as a GUI application.
/// GUI applications add a bunch of overhead, even if no windows are drawn. See
/// <https://randomascii.wordpress.com/2018/12/03/a-not-called-function-can-cause-a-5x-slowdown/>.
///
-/// This function was tested for equivalence to the shell32.dll implementation in
-/// Windows 10 Pro v1803, using an exhaustive test suite available at
-/// <https://gist.github.com/notriddle/dde431930c392e428055b2dc22e638f5> or
-/// <https://paste.gg/p/anonymous/47d6ed5f5bd549168b1c69c799825223>.
-unsafe fn parse_lp_cmd_line<F: Fn() -> OsString>(
- lp_cmd_line: *const u16,
+/// 2. It does not follow the modern C/C++ argv rules outlined in the first two links above.
+///
+/// This function was tested for equivalence to the C/C++ parsing rules using an
+/// extensive test suite available at
+/// <https://github.com/ChrisDenton/winarg/tree/std>.
+fn parse_lp_cmd_line<'a, F: Fn() -> OsString>(
+ lp_cmd_line: Option<WStrUnits<'a>>,
exe_name: F,
) -> Vec<OsString> {
- const BACKSLASH: u16 = '\\' as u16;
- const QUOTE: u16 = '"' as u16;
- const TAB: u16 = '\t' as u16;
- const SPACE: u16 = ' ' as u16;
+ const BACKSLASH: NonZeroU16 = NonZeroU16::new(b'\\' as u16).unwrap();
+ const QUOTE: NonZeroU16 = NonZeroU16::new(b'"' as u16).unwrap();
+ const TAB: NonZeroU16 = NonZeroU16::new(b'\t' as u16).unwrap();
+ const SPACE: NonZeroU16 = NonZeroU16::new(b' ' as u16).unwrap();
+
let mut ret_val = Vec::new();
- if lp_cmd_line.is_null() || *lp_cmd_line == 0 {
+ // If the cmd line pointer is null or it points to an empty string then
+ // return the name of the executable as argv[0].
+ if lp_cmd_line.as_ref().and_then(|cmd| cmd.peek()).is_none() {
ret_val.push(exe_name());
return ret_val;
}
- let mut cmd_line = {
- let mut end = 0;
- while *lp_cmd_line.offset(end) != 0 {
- end += 1;
- }
- slice::from_raw_parts(lp_cmd_line, end as usize)
- };
+ let mut code_units = lp_cmd_line.unwrap();
+
// The executable name at the beginning is special.
- cmd_line = match cmd_line[0] {
- // The executable name ends at the next quote mark,
- // no matter what.
- QUOTE => {
- let args = {
- let mut cut = cmd_line[1..].splitn(2, |&c| c == QUOTE);
- if let Some(exe) = cut.next() {
- ret_val.push(OsString::from_wide(exe));
- }
- cut.next()
- };
- if let Some(args) = args {
- args
- } else {
- return ret_val;
- }
- }
- // Implement quirk: when they say whitespace here,
- // they include the entire ASCII control plane:
- // "However, if lpCmdLine starts with any amount of whitespace, CommandLineToArgvW
- // will consider the first argument to be an empty string. Excess whitespace at the
- // end of lpCmdLine is ignored."
- 0..=SPACE => {
- ret_val.push(OsString::new());
- &cmd_line[1..]
- }
- // The executable name ends at the next whitespace,
- // no matter what.
- _ => {
- let args = {
- let mut cut = cmd_line.splitn(2, |&c| c > 0 && c <= SPACE);
- if let Some(exe) = cut.next() {
- ret_val.push(OsString::from_wide(exe));
- }
- cut.next()
- };
- if let Some(args) = args {
- args
- } else {
- return ret_val;
- }
+ let mut in_quotes = false;
+ let mut cur = Vec::new();
+ for w in &mut code_units {
+ match w {
+ // A quote mark always toggles `in_quotes` no matter what because
+ // there are no escape characters when parsing the executable name.
+ QUOTE => in_quotes = !in_quotes,
+ // If not `in_quotes` then whitespace ends argv[0].
+ SPACE | TAB if !in_quotes => break,
+ // In all other cases the code unit is taken literally.
+ _ => cur.push(w.get()),
}
- };
+ }
+ // Skip whitespace.
+ code_units.advance_while(|w| w == SPACE || w == TAB);
+ ret_val.push(OsString::from_wide(&cur));
+
+ // Parse the arguments according to these rules:
+ // * All code units are taken literally except space, tab, quote and backslash.
+ // * When not `in_quotes`, space and tab separate arguments. Consecutive spaces and tabs are
+ // treated as a single separator.
+ // * A space or tab `in_quotes` is taken literally.
+ // * A quote toggles `in_quotes` mode unless it's escaped. An escaped quote is taken literally.
+ // * A quote can be escaped if preceded by an odd number of backslashes.
+ // * If any number of backslashes is immediately followed by a quote then the number of
+ // backslashes is halved (rounding down).
+ // * Backslashes not followed by a quote are all taken literally.
+ // * If `in_quotes` then a quote can also be escaped using another quote
+ // (i.e. two consecutive quotes become one literal quote).
let mut cur = Vec::new();
let mut in_quotes = false;
- let mut was_in_quotes = false;
- let mut backslash_count: usize = 0;
- for &c in cmd_line {
- match c {
- // backslash
- BACKSLASH => {
- backslash_count += 1;
- was_in_quotes = false;
+ while let Some(w) = code_units.next() {
+ match w {
+ // If not `in_quotes`, a space or tab ends the argument.
+ SPACE | TAB if !in_quotes => {
+ ret_val.push(OsString::from_wide(&cur[..]));
+ cur.truncate(0);
+
+ // Skip whitespace.
+ code_units.advance_while(|w| w == SPACE || w == TAB);
}
- QUOTE if backslash_count % 2 == 0 => {
- cur.extend(iter::repeat(b'\\' as u16).take(backslash_count / 2));
- backslash_count = 0;
- if was_in_quotes {
- cur.push('"' as u16);
- was_in_quotes = false;
+ // Backslashes can escape quotes or backslashes but only if consecutive backslashes are followed by a quote.
+ BACKSLASH => {
+ let backslash_count = code_units.advance_while(|w| w == BACKSLASH) + 1;
+ if code_units.peek() == Some(QUOTE) {
+ cur.extend(iter::repeat(BACKSLASH.get()).take(backslash_count / 2));
+ // The quote is escaped if there are an odd number of backslashes.
+ if backslash_count % 2 == 1 {
+ code_units.next();
+ cur.push(QUOTE.get());
+ }
} else {
- was_in_quotes = in_quotes;
- in_quotes = !in_quotes;
+ // If there is no quote on the end then there is no escaping.
+ cur.extend(iter::repeat(BACKSLASH.get()).take(backslash_count));
}
}
- QUOTE if backslash_count % 2 != 0 => {
- cur.extend(iter::repeat(b'\\' as u16).take(backslash_count / 2));
- backslash_count = 0;
- was_in_quotes = false;
- cur.push(b'"' as u16);
- }
- SPACE | TAB if !in_quotes => {
- cur.extend(iter::repeat(b'\\' as u16).take(backslash_count));
- if !cur.is_empty() || was_in_quotes {
- ret_val.push(OsString::from_wide(&cur[..]));
- cur.truncate(0);
+ // If `in_quotes` and not backslash escaped (see above) then a quote either
+ // unsets `in_quote` or is escaped by another quote.
+ QUOTE if in_quotes => match code_units.peek() {
+ // Two consecutive quotes when `in_quotes` produces one literal quote.
+ Some(QUOTE) => {
+ cur.push(QUOTE.get());
+ code_units.next();
}
- backslash_count = 0;
- was_in_quotes = false;
- }
- _ => {
- cur.extend(iter::repeat(b'\\' as u16).take(backslash_count));
- backslash_count = 0;
- was_in_quotes = false;
- cur.push(c);
- }
+ // Otherwise set `in_quotes`.
+ Some(_) => in_quotes = false,
+ // The end of the command line.
+ // Push `cur` even if empty, which we do by breaking while `in_quotes` is still set.
+ None => break,
+ },
+ // If not `in_quotes` and not BACKSLASH escaped (see above) then a quote sets `in_quote`.
+ QUOTE => in_quotes = true,
+ // Everything else is always taken literally.
+ _ => cur.push(w.get()),
}
}
- cur.extend(iter::repeat(b'\\' as u16).take(backslash_count));
- // include empty quoted strings at the end of the arguments list
- if !cur.is_empty() || was_in_quotes || in_quotes {
+ // Push the final argument, if any.
+ if !cur.is_empty() || in_quotes {
ret_val.push(OsString::from_wide(&cur[..]));
}
ret_val
@@ -187,3 +185,52 @@ impl ExactSizeIterator for Args {
self.parsed_args_list.len()
}
}
+
+/// A safe iterator over a LPWSTR
+/// (aka a pointer to a series of UTF-16 code units terminated by a NULL).
+struct WStrUnits<'a> {
+ // The pointer must never be null...
+ lpwstr: NonNull<u16>,
+ // ...and the memory it points to must be valid for this lifetime.
+ lifetime: PhantomData<&'a [u16]>,
+}
+impl WStrUnits<'_> {
+ /// Create the iterator. Returns `None` if `lpwstr` is null.
+ ///
+ /// SAFETY: `lpwstr` must point to a null-terminated wide string that lives
+ /// at least as long as the lifetime of this struct.
+ unsafe fn new(lpwstr: *const u16) -> Option<Self> {
+ Some(Self { lpwstr: NonNull::new(lpwstr as _)?, lifetime: PhantomData })
+ }
+ fn peek(&self) -> Option<NonZeroU16> {
+ // SAFETY: It's always safe to read the current item because we don't
+ // ever move out of the array's bounds.
+ unsafe { NonZeroU16::new(*self.lpwstr.as_ptr()) }
+ }
+ /// Advance the iterator while `predicate` returns true.
+ /// Returns the number of items it advanced by.
+ fn advance_while<P: FnMut(NonZeroU16) -> bool>(&mut self, mut predicate: P) -> usize {
+ let mut counter = 0;
+ while let Some(w) = self.peek() {
+ if !predicate(w) {
+ break;
+ }
+ counter += 1;
+ self.next();
+ }
+ counter
+ }
+}
+impl Iterator for WStrUnits<'_> {
+ // This can never return zero as that marks the end of the string.
+ type Item = NonZeroU16;
+ fn next(&mut self) -> Option<NonZeroU16> {
+ // SAFETY: If NULL is reached we immediately return.
+ // Therefore it's safe to advance the pointer after that.
+ unsafe {
+ let next = self.peek()?;
+ self.lpwstr = NonNull::new_unchecked(self.lpwstr.as_ptr().add(1));
+ Some(next)
+ }
+ }
+}
diff --git a/library/std/src/sys/windows/args/tests.rs b/library/std/src/sys/windows/args/tests.rs
index 756a4361ea3de..82c32d08c5ea8 100644
--- a/library/std/src/sys/windows/args/tests.rs
+++ b/library/std/src/sys/windows/args/tests.rs
@@ -5,9 +5,9 @@ fn chk(string: &str, parts: &[&str]) {
let mut wide: Vec<u16> = OsString::from(string).encode_wide().collect();
wide.push(0);
let parsed =
- unsafe { parse_lp_cmd_line(wide.as_ptr() as *const u16, || OsString::from("TEST.EXE")) };
+ unsafe { parse_lp_cmd_line(WStrUnits::new(wide.as_ptr()), || OsString::from("TEST.EXE")) };
let expected: Vec<OsString> = parts.iter().map(|k| OsString::from(k)).collect();
- assert_eq!(parsed.as_slice(), expected.as_slice());
+ assert_eq!(parsed.as_slice(), expected.as_slice(), "{:?}", string);
}
#[test]
@@ -27,35 +27,65 @@ fn single_words() {
#[test]
fn official_examples() {
chk(r#"EXE "abc" d e"#, &["EXE", "abc", "d", "e"]);
- chk(r#"EXE a\\\b d"e f"g h"#, &["EXE", r#"a\\\b"#, "de fg", "h"]);
+ chk(r#"EXE a\\\b d"e f"g h"#, &["EXE", r"a\\\b", "de fg", "h"]);
chk(r#"EXE a\\\"b c d"#, &["EXE", r#"a\"b"#, "c", "d"]);
- chk(r#"EXE a\\\\"b c" d e"#, &["EXE", r#"a\\b c"#, "d", "e"]);
+ chk(r#"EXE a\\\\"b c" d e"#, &["EXE", r"a\\b c", "d", "e"]);
}
#[test]
fn whitespace_behavior() {
- chk(r#" test"#, &["", "test"]);
- chk(r#" test"#, &["", "test"]);
- chk(r#" test test2"#, &["", "test", "test2"]);
- chk(r#" test test2"#, &["", "test", "test2"]);
- chk(r#"test test2 "#, &["test", "test2"]);
- chk(r#"test test2 "#, &["test", "test2"]);
- chk(r#"test "#, &["test"]);
+ chk(" test", &["", "test"]);
+ chk(" test", &["", "test"]);
+ chk(" test test2", &["", "test", "test2"]);
+ chk(" test test2", &["", "test", "test2"]);
+ chk("test test2 ", &["test", "test2"]);
+ chk("test test2 ", &["test", "test2"]);
+ chk("test ", &["test"]);
}
#[test]
fn genius_quotes() {
chk(r#"EXE "" """#, &["EXE", "", ""]);
- chk(r#"EXE "" """"#, &["EXE", "", "\""]);
+ chk(r#"EXE "" """"#, &["EXE", "", r#"""#]);
chk(
r#"EXE "this is """all""" in the same argument""#,
- &["EXE", "this is \"all\" in the same argument"],
+ &["EXE", r#"this is "all" in the same argument"#],
);
- chk(r#"EXE "a"""#, &["EXE", "a\""]);
- chk(r#"EXE "a"" a"#, &["EXE", "a\"", "a"]);
+ chk(r#"EXE "a"""#, &["EXE", r#"a""#]);
+ chk(r#"EXE "a"" a"#, &["EXE", r#"a" a"#]);
// quotes cannot be escaped in command names
chk(r#""EXE" check"#, &["EXE", "check"]);
chk(r#""EXE check""#, &["EXE check"]);
- chk(r#""EXE """for""" check"#, &["EXE ", r#"for""#, "check"]);
- chk(r#""EXE \"for\" check"#, &[r#"EXE \"#, r#"for""#, "check"]);
+ chk(r#""EXE """for""" check"#, &["EXE for check"]);
+ chk(r#""EXE \"for\" check"#, &[r"EXE \for\ check"]);
+ chk(r#""EXE \" for \" check"#, &[r"EXE \", "for", r#"""#, "check"]);
+ chk(r#"E"X"E test"#, &["EXE", "test"]);
+ chk(r#"EX""E test"#, &["EXE", "test"]);
+}
+
+// from https://daviddeley.com/autohotkey/parameters/parameters.htm#WINCRULESEX
+#[test]
+fn post_2008() {
+ chk("EXE CallMeIshmael", &["EXE", "CallMeIshmael"]);
+ chk(r#"EXE "Call Me Ishmael""#, &["EXE", "Call Me Ishmael"]);
+ chk(r#"EXE Cal"l Me I"shmael"#, &["EXE", "Call Me Ishmael"]);
+ chk(r#"EXE CallMe\"Ishmael"#, &["EXE", r#"CallMe"Ishmael"#]);
+ chk(r#"EXE "CallMe\"Ishmael""#, &["EXE", r#"CallMe"Ishmael"#]);
+ chk(r#"EXE "Call Me Ishmael\\""#, &["EXE", r"Call Me Ishmael\"]);
+ chk(r#"EXE "CallMe\\\"Ishmael""#, &["EXE", r#"CallMe\"Ishmael"#]);
+ chk(r#"EXE a\\\b"#, &["EXE", r"a\\\b"]);
+ chk(r#"EXE "a\\\b""#, &["EXE", r"a\\\b"]);
+ chk(r#"EXE "\"Call Me Ishmael\"""#, &["EXE", r#""Call Me Ishmael""#]);
+ chk(r#"EXE "C:\TEST A\\""#, &["EXE", r"C:\TEST A\"]);
+ chk(r#"EXE "\"C:\TEST A\\\"""#, &["EXE", r#""C:\TEST A\""#]);
+ chk(r#"EXE "a b c" d e"#, &["EXE", "a b c", "d", "e"]);
+ chk(r#"EXE "ab\"c" "\\" d"#, &["EXE", r#"ab"c"#, r"\", "d"]);
+ chk(r#"EXE a\\\b d"e f"g h"#, &["EXE", r"a\\\b", "de fg", "h"]);
+ chk(r#"EXE a\\\"b c d"#, &["EXE", r#"a\"b"#, "c", "d"]);
+ chk(r#"EXE a\\\\"b c" d e"#, &["EXE", r"a\\b c", "d", "e"]);
+ // Double Double Quotes
+ chk(r#"EXE "a b c"""#, &["EXE", r#"a b c""#]);
+ chk(r#"EXE """CallMeIshmael""" b c"#, &["EXE", r#""CallMeIshmael""#, "b", "c"]);
+ chk(r#"EXE """Call Me Ishmael""""#, &["EXE", r#""Call Me Ishmael""#]);
+ chk(r#"EXE """"Call Me Ishmael"" b c"#, &["EXE", r#""Call"#, "Me", "Ishmael", "b", "c"]);
}
diff --git a/library/std/src/sys/windows/c.rs b/library/std/src/sys/windows/c.rs
index 63f9be7b7e350..023186c7a9067 100644
--- a/library/std/src/sys/windows/c.rs
+++ b/library/std/src/sys/windows/c.rs
@@ -781,7 +781,7 @@ extern "system" {
pub fn RemoveDirectoryW(lpPathName: LPCWSTR) -> BOOL;
pub fn SetFileAttributesW(lpFileName: LPCWSTR, dwFileAttributes: DWORD) -> BOOL;
pub fn SetLastError(dwErrCode: DWORD);
- pub fn GetCommandLineW() -> *mut LPCWSTR;
+ pub fn GetCommandLineW() -> LPWSTR;
pub fn GetTempPathW(nBufferLength: DWORD, lpBuffer: LPCWSTR) -> DWORD;
pub fn GetCurrentProcess() -> HANDLE;
pub fn GetCurrentThread() -> HANDLE;