6 files changed, 673 insertions, 0 deletions
diff --git a/src/tools/rust-analyzer/crates/stdx/Cargo.toml b/src/tools/rust-analyzer/crates/stdx/Cargo.toml
new file mode 100644
index 000000000..092b99ae5
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/stdx/Cargo.toml
@@ -0,0 +1,24 @@
+[package]
+name = "stdx"
+version = "0.0.0"
+description = "TBD"
+license = "MIT OR Apache-2.0"
+edition = "2021"
+rust-version = "1.57"
+
+[lib]
+doctest = false
+
+[dependencies]
+libc = "0.2.126"
+backtrace = { version = "0.3.65", optional = true }
+always-assert = { version = "0.1.2", features = ["log"] }
+# Think twice before adding anything here
+
+[target.'cfg(windows)'.dependencies]
+miow = "0.4.0"
+winapi = { version = "0.3.9", features = ["winerror"] }
+
+[features]
+# Uncomment to enable for the whole crate graph
+# default = [ "backtrace" ]
diff --git a/src/tools/rust-analyzer/crates/stdx/src/lib.rs b/src/tools/rust-analyzer/crates/stdx/src/lib.rs
new file mode 100644
index 000000000..b4d45206c
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/stdx/src/lib.rs
@@ -0,0 +1,247 @@
+//! Missing batteries for standard libraries.
+
+#![warn(rust_2018_idioms, unused_lifetimes, semicolon_in_expressions_from_macros)]
+
+use std::process::Command;
+use std::{cmp::Ordering, ops, time::Instant};
+use std::{io as sio, iter};
+
+mod macros;
+pub mod process;
+pub mod panic_context;
+pub mod non_empty_vec;
+
+pub use always_assert::{always, never};
+
+#[inline(always)]
+pub fn is_ci() -> bool {
+    option_env!("CI").is_some()
+}
+
+#[must_use]
+pub fn timeit(label: &'static str) -> impl Drop {
+    let start = Instant::now();
+    defer(move || eprintln!("{}: {:.2?}", label, start.elapsed()))
+}
+
+/// Prints backtrace to stderr, useful for debugging.
+pub fn print_backtrace() {
+    #[cfg(feature = "backtrace")]
+    eprintln!("{:?}", backtrace::Backtrace::new());
+
+    #[cfg(not(feature = "backtrace"))]
+    eprintln!(
+        r#"Enable the backtrace feature.
+Uncomment `default = [ "backtrace" ]` in `crates/stdx/Cargo.toml`.
+"#
+    );
+}
+
+pub fn to_lower_snake_case(s: &str) -> String {
+    to_snake_case(s, char::to_ascii_lowercase)
+}
+pub fn to_upper_snake_case(s: &str) -> String {
+    to_snake_case(s, char::to_ascii_uppercase)
+}
+
+// Code partially taken from rust/compiler/rustc_lint/src/nonstandard_style.rs
+// commit: 9626f2b
+fn to_snake_case<F: Fn(&char) -> char>(mut s: &str, change_case: F) -> String {
+    let mut words = vec![];
+
+    // Preserve leading underscores
+    s = s.trim_start_matches(|c: char| {
+        if c == '_' {
+            words.push(String::new());
+            true
+        } else {
+            false
+        }
+    });
+
+    for s in s.split('_') {
+        let mut last_upper = false;
+        let mut buf = String::new();
+
+        if s.is_empty() {
+            continue;
+        }
+
+        for ch in s.chars() {
+            if !buf.is_empty() && buf != "'" && ch.is_uppercase() && !last_upper {
+                words.push(buf);
+                buf = String::new();
+            }
+
+            last_upper = ch.is_uppercase();
+            buf.extend(iter::once(change_case(&ch)));
+        }
+
+        words.push(buf);
+    }
+
+    words.join("_")
+}
+
+pub fn replace(buf: &mut String, from: char, to: &str) {
+    if !buf.contains(from) {
+        return;
+    }
+    // FIXME: do this in place.
+    *buf = buf.replace(from, to);
+}
+
+pub fn trim_indent(mut text: &str) -> String {
+    if text.starts_with('\n') {
+        text = &text[1..];
+    }
+    let indent = text
+        .lines()
+        .filter(|it| !it.trim().is_empty())
+        .map(|it| it.len() - it.trim_start().len())
+        .min()
+        .unwrap_or(0);
+    text.split_inclusive('\n')
+        .map(
+            |line| {
+                if line.len() <= indent {
+                    line.trim_start_matches(' ')
+                } else {
+                    &line[indent..]
+                }
+            },
+        )
+        .collect()
+}
+
+pub fn equal_range_by<T, F>(slice: &[T], mut key: F) -> ops::Range<usize>
+where
+    F: FnMut(&T) -> Ordering,
+{
+    let start = slice.partition_point(|it| key(it) == Ordering::Less);
+    let len = slice[start..].partition_point(|it| key(it) == Ordering::Equal);
+    start..start + len
+}
+
+#[must_use]
+pub fn defer<F: FnOnce()>(f: F) -> impl Drop {
+    struct D<F: FnOnce()>(Option<F>);
+    impl<F: FnOnce()> Drop for D<F> {
+        fn drop(&mut self) {
+            if let Some(f) = self.0.take() {
+                f();
+            }
+        }
+    }
+    D(Some(f))
+}
+
+/// A [`std::process::Child`] wrapper that will kill the child on drop.
+#[cfg_attr(not(target_arch = "wasm32"), repr(transparent))]
+#[derive(Debug)]
+pub struct JodChild(pub std::process::Child);
+
+impl ops::Deref for JodChild {
+    type Target = std::process::Child;
+    fn deref(&self) -> &std::process::Child {
+        &self.0
+    }
+}
+
+impl ops::DerefMut for JodChild {
+    fn deref_mut(&mut self) -> &mut std::process::Child {
+        &mut self.0
+    }
+}
+
+impl Drop for JodChild {
+    fn drop(&mut self) {
+        let _ = self.0.kill();
+        let _ = self.0.wait();
+    }
+}
+
+impl JodChild {
+    pub fn spawn(mut command: Command) -> sio::Result<Self> {
+        command.spawn().map(Self)
+    }
+
+    pub fn into_inner(self) -> std::process::Child {
+        if cfg!(target_arch = "wasm32") {
+            panic!("no processes on wasm");
+        }
+        // SAFETY: repr transparent, except on WASM
+        unsafe { std::mem::transmute::<JodChild, std::process::Child>(self) }
+    }
+}
+
+// feature: iter_order_by
+// Iterator::eq_by
+pub fn iter_eq_by<I, I2, F>(this: I2, other: I, mut eq: F) -> bool
+where
+    I: IntoIterator,
+    I2: IntoIterator,
+    F: FnMut(I2::Item, I::Item) -> bool,
+{
+    let mut other = other.into_iter();
+    let mut this = this.into_iter();
+
+    loop {
+        let x = match this.next() {
+            None => return other.next().is_none(),
+            Some(val) => val,
+        };
+
+        let y = match other.next() {
+            None => return false,
+            Some(val) => val,
+        };
+
+        if !eq(x, y) {
+            return false;
+        }
+    }
+}
+
+/// Returns all final segments of the argument, longest first.
+pub fn slice_tails<T>(this: &[T]) -> impl Iterator<Item = &[T]> {
+    (0..this.len()).map(|i| &this[i..])
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_trim_indent() {
+        assert_eq!(trim_indent(""), "");
+        assert_eq!(
+            trim_indent(
+                "
+            hello
+            world
+"
+            ),
+            "hello\nworld\n"
+        );
+        assert_eq!(
+            trim_indent(
+                "
+            hello
+            world"
+            ),
+            "hello\nworld"
+        );
+        assert_eq!(trim_indent("    hello\n    world\n"), "hello\nworld\n");
+        assert_eq!(
+            trim_indent(
+                "
+            fn main() {
+                return 92;
+            }
+        "
+            ),
+            "fn main() {\n    return 92;\n}\n"
+        );
+    }
+}
diff --git a/src/tools/rust-analyzer/crates/stdx/src/macros.rs b/src/tools/rust-analyzer/crates/stdx/src/macros.rs
new file mode 100644
index 000000000..d91fc690c
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/stdx/src/macros.rs
@@ -0,0 +1,47 @@
+//! Convenience macros.
+
+#[macro_export]
+macro_rules! eprintln {
+    ($($tt:tt)*) => {{
+        if $crate::is_ci() {
+            panic!("Forgot to remove debug-print?")
+        }
+        std::eprintln!($($tt)*)
+    }}
+}
+
+/// Appends formatted string to a `String`.
+#[macro_export]
+macro_rules! format_to {
+    ($buf:expr) => ();
+    ($buf:expr, $lit:literal $($arg:tt)*) => {
+        { use ::std::fmt::Write as _; let _ = ::std::write!($buf, $lit $($arg)*); }
+    };
+}
+
+/// Generates `From` impls for `Enum E { Foo(Foo), Bar(Bar) }` enums
+///
+/// # Example
+///
+/// ```rust
+/// impl_from!(Struct, Union, Enum for Adt);
+/// ```
+#[macro_export]
+macro_rules! impl_from {
+    ($($variant:ident $(($($sub_variant:ident),*))?),* for $enum:ident) => {
+        $(
+            impl From<$variant> for $enum {
+                fn from(it: $variant) -> $enum {
+                    $enum::$variant(it)
+                }
+            }
+            $($(
+                impl From<$sub_variant> for $enum {
+                    fn from(it: $sub_variant) -> $enum {
+                        $enum::$variant($variant::$sub_variant(it))
+                    }
+                }
+            )*)?
+        )*
+    }
+}
diff --git a/src/tools/rust-analyzer/crates/stdx/src/non_empty_vec.rs b/src/tools/rust-analyzer/crates/stdx/src/non_empty_vec.rs
new file mode 100644
index 000000000..342194c78
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/stdx/src/non_empty_vec.rs
@@ -0,0 +1,39 @@
+//! See [`NonEmptyVec`].
+
+/// A [`Vec`] that is guaranteed to at least contain one element.
+pub struct NonEmptyVec<T> {
+    first: T,
+    rest: Vec<T>,
+}
+
+impl<T> NonEmptyVec<T> {
+    #[inline]
+    pub fn new(first: T) -> Self {
+        NonEmptyVec { first, rest: Vec::new() }
+    }
+
+    #[inline]
+    pub fn last_mut(&mut self) -> &mut T {
+        self.rest.last_mut().unwrap_or(&mut self.first)
+    }
+
+    #[inline]
+    pub fn pop(&mut self) -> Option<T> {
+        self.rest.pop()
+    }
+
+    #[inline]
+    pub fn push(&mut self, value: T) {
+        self.rest.push(value)
+    }
+
+    #[inline]
+    pub fn len(&self) -> usize {
+        1 + self.rest.len()
+    }
+
+    #[inline]
+    pub fn into_last(mut self) -> T {
+        self.rest.pop().unwrap_or(self.first)
+    }
+}
diff --git a/src/tools/rust-analyzer/crates/stdx/src/panic_context.rs b/src/tools/rust-analyzer/crates/stdx/src/panic_context.rs
new file mode 100644
index 000000000..f8fafc5a6
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/stdx/src/panic_context.rs
@@ -0,0 +1,49 @@
+//! A micro-crate to enhance panic messages with context info.
+//!
+//! FIXME: upstream to <https://github.com/kriomant/panic-context> ?
+
+use std::{cell::RefCell, panic, sync::Once};
+
+pub fn enter(context: String) -> PanicContext {
+    static ONCE: Once = Once::new();
+    ONCE.call_once(PanicContext::init);
+
+    with_ctx(|ctx| ctx.push(context));
+    PanicContext { _priv: () }
+}
+
+#[must_use]
+pub struct PanicContext {
+    _priv: (),
+}
+
+impl PanicContext {
+    fn init() {
+        let default_hook = panic::take_hook();
+        let hook = move |panic_info: &panic::PanicInfo<'_>| {
+            with_ctx(|ctx| {
+                if !ctx.is_empty() {
+                    eprintln!("Panic context:");
+                    for frame in ctx.iter() {
+                        eprintln!("> {}\n", frame);
+                    }
+                }
+                default_hook(panic_info);
+            });
+        };
+        panic::set_hook(Box::new(hook));
+    }
+}
+
+impl Drop for PanicContext {
+    fn drop(&mut self) {
+        with_ctx(|ctx| assert!(ctx.pop().is_some()));
+    }
+}
+
+fn with_ctx(f: impl FnOnce(&mut Vec<String>)) {
+    thread_local! {
+        static CTX: RefCell<Vec<String>> = RefCell::new(Vec::new());
+    }
+    CTX.with(|ctx| f(&mut *ctx.borrow_mut()));
+}
diff --git a/src/tools/rust-analyzer/crates/stdx/src/process.rs b/src/tools/rust-analyzer/crates/stdx/src/process.rs
new file mode 100644
index 000000000..e5aa34365
--- /dev/null
+++ b/src/tools/rust-analyzer/crates/stdx/src/process.rs
@@ -0,0 +1,267 @@
+//! Read both stdout and stderr of child without deadlocks.
+//!
+//! <https://github.com/rust-lang/cargo/blob/905af549966f23a9288e9993a85d1249a5436556/crates/cargo-util/src/read2.rs>
+//! <https://github.com/rust-lang/cargo/blob/58a961314437258065e23cb6316dfc121d96fb71/crates/cargo-util/src/process_builder.rs#L231>
+
+use std::{
+    io,
+    process::{ChildStderr, ChildStdout, Command, Output, Stdio},
+};
+
+use crate::JodChild;
+
+pub fn streaming_output(
+    out: ChildStdout,
+    err: ChildStderr,
+    on_stdout_line: &mut dyn FnMut(&str),
+    on_stderr_line: &mut dyn FnMut(&str),
+) -> io::Result<(Vec<u8>, Vec<u8>)> {
+    let mut stdout = Vec::new();
+    let mut stderr = Vec::new();
+
+    imp::read2(out, err, &mut |is_out, data, eof| {
+        let idx = if eof {
+            data.len()
+        } else {
+            match data.iter().rposition(|b| *b == b'\n') {
+                Some(i) => i + 1,
+                None => return,
+            }
+        };
+        {
+            // scope for new_lines
+            let new_lines = {
+                let dst = if is_out { &mut stdout } else { &mut stderr };
+                let start = dst.len();
+                let data = data.drain(..idx);
+                dst.extend(data);
+                &dst[start..]
+            };
+            for line in String::from_utf8_lossy(new_lines).lines() {
+                if is_out {
+                    on_stdout_line(line);
+                } else {
+                    on_stderr_line(line);
+                }
+            }
+        }
+    })?;
+
+    Ok((stdout, stderr))
+}
+
+pub fn spawn_with_streaming_output(
+    mut cmd: Command,
+    on_stdout_line: &mut dyn FnMut(&str),
+    on_stderr_line: &mut dyn FnMut(&str),
+) -> io::Result<Output> {
+    let cmd = cmd.stdout(Stdio::piped()).stderr(Stdio::piped()).stdin(Stdio::null());
+
+    let mut child = JodChild(cmd.spawn()?);
+    let (stdout, stderr) = streaming_output(
+        child.stdout.take().unwrap(),
+        child.stderr.take().unwrap(),
+        on_stdout_line,
+        on_stderr_line,
+    )?;
+    let status = child.wait()?;
+    Ok(Output { status, stdout, stderr })
+}
+
+#[cfg(unix)]
+mod imp {
+    use std::{
+        io::{self, prelude::*},
+        mem,
+        os::unix::prelude::*,
+        process::{ChildStderr, ChildStdout},
+    };
+
+    pub(crate) fn read2(
+        mut out_pipe: ChildStdout,
+        mut err_pipe: ChildStderr,
+        data: &mut dyn FnMut(bool, &mut Vec<u8>, bool),
+    ) -> io::Result<()> {
+        unsafe {
+            libc::fcntl(out_pipe.as_raw_fd(), libc::F_SETFL, libc::O_NONBLOCK);
+            libc::fcntl(err_pipe.as_raw_fd(), libc::F_SETFL, libc::O_NONBLOCK);
+        }
+
+        let mut out_done = false;
+        let mut err_done = false;
+        let mut out = Vec::new();
+        let mut err = Vec::new();
+
+        let mut fds: [libc::pollfd; 2] = unsafe { mem::zeroed() };
+        fds[0].fd = out_pipe.as_raw_fd();
+        fds[0].events = libc::POLLIN;
+        fds[1].fd = err_pipe.as_raw_fd();
+        fds[1].events = libc::POLLIN;
+        let mut nfds = 2;
+        let mut errfd = 1;
+
+        while nfds > 0 {
+            // wait for either pipe to become readable using `select`
+            let r = unsafe { libc::poll(fds.as_mut_ptr(), nfds, -1) };
+            if r == -1 {
+                let err = io::Error::last_os_error();
+                if err.kind() == io::ErrorKind::Interrupted {
+                    continue;
+                }
+                return Err(err);
+            }
+
+            // Read as much as we can from each pipe, ignoring EWOULDBLOCK or
+            // EAGAIN. If we hit EOF, then this will happen because the underlying
+            // reader will return Ok(0), in which case we'll see `Ok` ourselves. In
+            // this case we flip the other fd back into blocking mode and read
+            // whatever's leftover on that file descriptor.
+            let handle = |res: io::Result<_>| match res {
+                Ok(_) => Ok(true),
+                Err(e) => {
+                    if e.kind() == io::ErrorKind::WouldBlock {
+                        Ok(false)
+                    } else {
+                        Err(e)
+                    }
+                }
+            };
+            if !err_done && fds[errfd].revents != 0 && handle(err_pipe.read_to_end(&mut err))? {
+                err_done = true;
+                nfds -= 1;
+            }
+            data(false, &mut err, err_done);
+            if !out_done && fds[0].revents != 0 && handle(out_pipe.read_to_end(&mut out))? {
+                out_done = true;
+                fds[0].fd = err_pipe.as_raw_fd();
+                errfd = 0;
+                nfds -= 1;
+            }
+            data(true, &mut out, out_done);
+        }
+        Ok(())
+    }
+}
+
+#[cfg(windows)]
+mod imp {
+    use std::{
+        io,
+        os::windows::prelude::*,
+        process::{ChildStderr, ChildStdout},
+        slice,
+    };
+
+    use miow::{
+        iocp::{CompletionPort, CompletionStatus},
+        pipe::NamedPipe,
+        Overlapped,
+    };
+    use winapi::shared::winerror::ERROR_BROKEN_PIPE;
+
+    struct Pipe<'a> {
+        dst: &'a mut Vec<u8>,
+        overlapped: Overlapped,
+        pipe: NamedPipe,
+        done: bool,
+    }
+
+    pub(crate) fn read2(
+        out_pipe: ChildStdout,
+        err_pipe: ChildStderr,
+        data: &mut dyn FnMut(bool, &mut Vec<u8>, bool),
+    ) -> io::Result<()> {
+        let mut out = Vec::new();
+        let mut err = Vec::new();
+
+        let port = CompletionPort::new(1)?;
+        port.add_handle(0, &out_pipe)?;
+        port.add_handle(1, &err_pipe)?;
+
+        unsafe {
+            let mut out_pipe = Pipe::new(out_pipe, &mut out);
+            let mut err_pipe = Pipe::new(err_pipe, &mut err);
+
+            out_pipe.read()?;
+            err_pipe.read()?;
+
+            let mut status = [CompletionStatus::zero(), CompletionStatus::zero()];
+
+            while !out_pipe.done || !err_pipe.done {
+                for status in port.get_many(&mut status, None)? {
+                    if status.token() == 0 {
+                        out_pipe.complete(status);
+                        data(true, out_pipe.dst, out_pipe.done);
+                        out_pipe.read()?;
+                    } else {
+                        err_pipe.complete(status);
+                        data(false, err_pipe.dst, err_pipe.done);
+                        err_pipe.read()?;
+                    }
+                }
+            }
+
+            Ok(())
+        }
+    }
+
+    impl<'a> Pipe<'a> {
+        unsafe fn new<P: IntoRawHandle>(p: P, dst: &'a mut Vec<u8>) -> Pipe<'a> {
+            Pipe {
+                dst,
+                pipe: NamedPipe::from_raw_handle(p.into_raw_handle()),
+                overlapped: Overlapped::zero(),
+                done: false,
+            }
+        }
+
+        unsafe fn read(&mut self) -> io::Result<()> {
+            let dst = slice_to_end(self.dst);
+            match self.pipe.read_overlapped(dst, self.overlapped.raw()) {
+                Ok(_) => Ok(()),
+                Err(e) => {
+                    if e.raw_os_error() == Some(ERROR_BROKEN_PIPE as i32) {
+                        self.done = true;
+                        Ok(())
+                    } else {
+                        Err(e)
+                    }
+                }
+            }
+        }
+
+        unsafe fn complete(&mut self, status: &CompletionStatus) {
+            let prev = self.dst.len();
+            self.dst.set_len(prev + status.bytes_transferred() as usize);
+            if status.bytes_transferred() == 0 {
+                self.done = true;
+            }
+        }
+    }
+
+    unsafe fn slice_to_end(v: &mut Vec<u8>) -> &mut [u8] {
+        if v.capacity() == 0 {
+            v.reserve(16);
+        }
+        if v.capacity() == v.len() {
+            v.reserve(1);
+        }
+        slice::from_raw_parts_mut(v.as_mut_ptr().add(v.len()), v.capacity() - v.len())
+    }
+}
+
+#[cfg(target_arch = "wasm32")]
+mod imp {
+    use std::{
+        io,
+        process::{ChildStderr, ChildStdout},
+    };
+
+    pub(crate) fn read2(
+        _out_pipe: ChildStdout,
+        _err_pipe: ChildStderr,
+        _data: &mut dyn FnMut(bool, &mut Vec<u8>, bool),
+    ) -> io::Result<()> {
+        panic!("no processes on wasm")
+    }
+}