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    use crate::process_error::ProcessError;
    use crate::read2;

    use anyhow::{bail, Context, Result};
    use jobserver::Client;
    use shell_escape::escape;
    use tempfile::NamedTempFile;

    use std::collections::BTreeMap;
    use std::env;
    use std::ffi::{OsStr, OsString};
    use std::fmt;
    use std::io::{self, Write};
    use std::iter::once;
    use std::path::Path;
    use std::process::{Command, ExitStatus, Output, Stdio};

    /// A builder object for an external process, similar to [`std::process::Command`].
    #[derive(Clone, Debug)]
    pub struct ProcessBuilder {
        /// The program to execute.
        program: OsString,
        /// A list of arguments to pass to the program.
        args: Vec<OsString>,
        /// Any environment variables that should be set for the program.
        env: BTreeMap<String, Option<OsString>>,
        /// The directory to run the program from.
        cwd: Option<OsString>,
        /// A list of wrappers that wrap the original program when calling
        /// [`ProcessBuilder::wrapped`]. The last one is the outermost one.
        wrappers: Vec<OsString>,
        /// The `make` jobserver. See the [jobserver crate] for
        /// more information.
        ///
        /// [jobserver crate]: https://docs.rs/jobserver/
        jobserver: Option<Client>,
        /// `true` to include environment variable in display.
        display_env_vars: bool,
        /// `true` to retry with an argfile if hitting "command line too big" error.
        /// See [`ProcessBuilder::retry_with_argfile`] for more information.
        retry_with_argfile: bool,
        /// Data to write to stdin.
        stdin: Option<Vec<u8>>,
    }

    impl fmt::Display for ProcessBuilder {
        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
            write!(f, "`")?;

            if self.display_env_vars {
                for (key, val) in self.env.iter() {
                    if let Some(val) = val {
                        let val = escape(val.to_string_lossy());
                        if cfg!(windows) {
                            write!(f, "set {}={}&& ", key, val)?;
                        } else {
                            write!(f, "{}={} ", key, val)?;
                        }
                    }
                }
            }

            write!(f, "{}", self.get_program().to_string_lossy())?;

            for arg in self.get_args() {
                write!(f, " {}", escape(arg.to_string_lossy()))?;
            }

            write!(f, "`")
        }
    }

    impl ProcessBuilder {
        /// Creates a new [`ProcessBuilder`] with the given executable path.
        pub fn new<T: AsRef<OsStr>>(cmd: T) -> ProcessBuilder {
            ProcessBuilder {
                program: cmd.as_ref().to_os_string(),
                args: Vec::new(),
                cwd: None,
                env: BTreeMap::new(),
                wrappers: Vec::new(),
                jobserver: None,
                display_env_vars: false,
                retry_with_argfile: false,
                stdin: None,
            }
        }

        /// (chainable) Sets the executable for the process.
        pub fn program<T: AsRef<OsStr>>(&mut self, program: T) -> &mut ProcessBuilder {
            self.program = program.as_ref().to_os_string();
            self
        }

        /// (chainable) Adds `arg` to the args list.
        pub fn arg<T: AsRef<OsStr>>(&mut self, arg: T) -> &mut ProcessBuilder {
            self.args.push(arg.as_ref().to_os_string());
            self
        }

        /// (chainable) Adds multiple `args` to the args list.
        pub fn args<T: AsRef<OsStr>>(&mut self, args: &[T]) -> &mut ProcessBuilder {
            self.args
                .extend(args.iter().map(|t| t.as_ref().to_os_string()));
            self
        }

        /// (chainable) Replaces the args list with the given `args`.
        pub fn args_replace<T: AsRef<OsStr>>(&mut self, args: &[T]) -> &mut ProcessBuilder {
            if let Some(program) = self.wrappers.pop() {
                // User intend to replace all args, so we
                // - use the outermost wrapper as the main program, and
                // - cleanup other inner wrappers.
                self.program = program;
                self.wrappers = Vec::new();
            }
            self.args = args.iter().map(|t| t.as_ref().to_os_string()).collect();
            self
        }

        /// (chainable) Sets the current working directory of the process.
        pub fn cwd<T: AsRef<OsStr>>(&mut self, path: T) -> &mut ProcessBuilder {
            self.cwd = Some(path.as_ref().to_os_string());
            self
        }

        /// (chainable) Sets an environment variable for the process.
        pub fn env<T: AsRef<OsStr>>(&mut self, key: &str, val: T) -> &mut ProcessBuilder {
            self.env
                .insert(key.to_string(), Some(val.as_ref().to_os_string()));
            self
        }

        /// (chainable) Unsets an environment variable for the process.
        pub fn env_remove(&mut self, key: &str) -> &mut ProcessBuilder {
            self.env.insert(key.to_string(), None);
            self
        }

        /// Gets the executable name.
        pub fn get_program(&self) -> &OsString {
            self.wrappers.last().unwrap_or(&self.program)
        }

        /// Gets the program arguments.
        pub fn get_args(&self) -> impl Iterator<Item = &OsString> {
            self.wrappers
                .iter()
                .rev()
                .chain(once(&self.program))
                .chain(self.args.iter())
                .skip(1) // Skip the main `program
        }

        /// Gets the current working directory for the process.
        pub fn get_cwd(&self) -> Option<&Path> {
            self.cwd.as_ref().map(Path::new)
        }

        /// Gets an environment variable as the process will see it (will inherit from environment
        /// unless explicitally unset).
        pub fn get_env(&self, var: &str) -> Option<OsString> {
            self.env
                .get(var)
                .cloned()
                .or_else(|| Some(env::var_os(var)))
                .and_then(|s| s)
        }

        /// Gets all environment variables explicitly set or unset for the process (not inherited
        /// vars).
        pub fn get_envs(&self) -> &BTreeMap<String, Option<OsString>> {
            &self.env
        }

        /// Sets the `make` jobserver. See the [jobserver crate][jobserver_docs] for
        /// more information.
        ///
        /// [jobserver_docs]: https://docs.rs/jobserver/0.1.6/jobserver/
        pub fn inherit_jobserver(&mut self, jobserver: &Client) -> &mut Self {
            self.jobserver = Some(jobserver.clone());
            self
        }

        /// Enables environment variable display.
        pub fn display_env_vars(&mut self) -> &mut Self {
            self.display_env_vars = true;
            self
        }

        /// Enables retrying with an argfile if hitting "command line too big" error
        ///
        /// This is primarily for the `@path` arg of rustc and rustdoc, which treat
        /// each line as an command-line argument, so `LF` and `CRLF` bytes are not
        /// valid as an argument for argfile at this moment.
        /// For example, `RUSTDOCFLAGS="--crate-version foo\nbar" cargo doc` is
        /// valid when invoking from command-line but not from argfile.
        ///
        /// To sum up, the limitations of the argfile are:
        ///
        /// - Must be valid UTF-8 encoded.
        /// - Must not contain any newlines in each argument.
        ///
        /// Ref:
        ///
        /// - <https://doc.rust-lang.org/rustdoc/command-line-arguments.html#path-load-command-line-flags-from-a-path>
        /// - <https://doc.rust-lang.org/rustc/command-line-arguments.html#path-load-command-line-flags-from-a-path>
        pub fn retry_with_argfile(&mut self, enabled: bool) -> &mut Self {
            self.retry_with_argfile = enabled;
            self
        }

        /// Sets a value that will be written to stdin of the process on launch.
        pub fn stdin<T: Into<Vec<u8>>>(&mut self, stdin: T) -> &mut Self {
            self.stdin = Some(stdin.into());
            self
        }

        fn should_retry_with_argfile(&self, err: &io::Error) -> bool {
            self.retry_with_argfile && imp::command_line_too_big(err)
        }

        /// Like [`Command::status`] but with a better error message.
        pub fn status(&self) -> Result<ExitStatus> {
            self._status()
                .with_context(|| ProcessError::could_not_execute(self))
        }

        fn _status(&self) -> io::Result<ExitStatus> {
            if !debug_force_argfile(self.retry_with_argfile) {
                let mut cmd = self.build_command();
                match cmd.spawn() {
                    Err(ref e) if self.should_retry_with_argfile(e) => {}
                    Err(e) => return Err(e),
                    Ok(mut child) => return child.wait(),
                }
            }
            let (mut cmd, argfile) = self.build_command_with_argfile()?;
            let status = cmd.spawn()?.wait();
            close_tempfile_and_log_error(argfile);
            status
        }

        /// Runs the process, waiting for completion, and mapping non-success exit codes to an error.
        pub fn exec(&self) -> Result<()> {
            let exit = self.status()?;
            if exit.success() {
                Ok(())
            } else {
                Err(ProcessError::new(
                    &format!("process didn't exit successfully: {}", self),
                    Some(exit),
                    None,
                )
                .into())
            }
        }

        /// Replaces the current process with the target process.
        ///
        /// On Unix, this executes the process using the Unix syscall `execvp`, which will block
        /// this process, and will only return if there is an error.
        ///
        /// On Windows this isn't technically possible. Instead we emulate it to the best of our
        /// ability. One aspect we fix here is that we specify a handler for the Ctrl-C handler.
        /// In doing so (and by effectively ignoring it) we should emulate proxying Ctrl-C
        /// handling to the application at hand, which will either terminate or handle it itself.
        /// According to Microsoft's documentation at
        /// <https://docs.microsoft.com/en-us/windows/console/ctrl-c-and-ctrl-break-signals>.
        /// the Ctrl-C signal is sent to all processes attached to a terminal, which should
        /// include our child process. If the child terminates then we'll reap them in Cargo
        /// pretty quickly, and if the child handles the signal then we won't terminate
        /// (and we shouldn't!) until the process itself later exits.
        pub fn exec_replace(&self) -> Result<()> {
            imp::exec_replace(self)
        }

        /// Like [`Command::output`] but with a better error message.
        pub fn output(&self) -> Result<Output> {
            self._output()
                .with_context(|| ProcessError::could_not_execute(self))
        }

        fn _output(&self) -> io::Result<Output> {
            if !debug_force_argfile(self.retry_with_argfile) {
                let mut cmd = self.build_command();
                match piped(&mut cmd, self.stdin.is_some()).spawn() {
                    Err(ref e) if self.should_retry_with_argfile(e) => {}
                    Err(e) => return Err(e),
                    Ok(mut child) => {
                        if let Some(stdin) = &self.stdin {
                            child.stdin.take().unwrap().write_all(stdin)?;
                        }
                        return child.wait_with_output();
                    }
                }
            }
            let (mut cmd, argfile) = self.build_command_with_argfile()?;
            let mut child = piped(&mut cmd, self.stdin.is_some()).spawn()?;
            if let Some(stdin) = &self.stdin {
                child.stdin.take().unwrap().write_all(stdin)?;
            }
            let output = child.wait_with_output();
            close_tempfile_and_log_error(argfile);
            output
        }

        /// Executes the process, returning the stdio output, or an error if non-zero exit status.
        pub fn exec_with_output(&self) -> Result<Output> {
            let output = self.output()?;
            if output.status.success() {
                Ok(output)
            } else {
                Err(ProcessError::new(
                    &format!("process didn't exit successfully: {}", self),
                    Some(output.status),
                    Some(&output),
                )
                .into())
            }
        }

        /// Executes a command, passing each line of stdout and stderr to the supplied callbacks, which
        /// can mutate the string data.
        ///
        /// If any invocations of these function return an error, it will be propagated.
        ///
        /// If `capture_output` is true, then all the output will also be buffered
        /// and stored in the returned `Output` object. If it is false, no caching
        /// is done, and the callbacks are solely responsible for handling the
        /// output.
        pub fn exec_with_streaming(
            &self,
            on_stdout_line: &mut dyn FnMut(&str) -> Result<()>,
            on_stderr_line: &mut dyn FnMut(&str) -> Result<()>,
            capture_output: bool,
        ) -> Result<Output> {
            let mut stdout = Vec::new();
            let mut stderr = Vec::new();

            let mut callback_error = None;
            let mut stdout_pos = 0;
            let mut stderr_pos = 0;

            let spawn = |mut cmd| {
                if !debug_force_argfile(self.retry_with_argfile) {
                    match piped(&mut cmd, false).spawn() {
                        Err(ref e) if self.should_retry_with_argfile(e) => {}
                        Err(e) => return Err(e),
                        Ok(child) => return Ok((child, None)),
                    }
                }
                let (mut cmd, argfile) = self.build_command_with_argfile()?;
                Ok((piped(&mut cmd, false).spawn()?, Some(argfile)))
            };

            let status = (|| {
                let cmd = self.build_command();
                let (mut child, argfile) = spawn(cmd)?;
                let out = child.stdout.take().unwrap();
                let err = child.stderr.take().unwrap();
                read2(out, err, &mut |is_out, data, eof| {
                    let pos = if is_out {
                        &mut stdout_pos
                    } else {
                        &mut stderr_pos
                    };
                    let idx = if eof {
                        data.len()
                    } else {
                        match data[*pos..].iter().rposition(|b| *b == b'\n') {
                            Some(i) => *pos + i + 1,
                            None => {
                                *pos = data.len();
                                return;
                            }
                        }
                    };

                    let new_lines = &data[..idx];

                    for line in String::from_utf8_lossy(new_lines).lines() {
                        if callback_error.is_some() {
                            break;
                        }
                        let callback_result = if is_out {
                            on_stdout_line(line)
                        } else {
                            on_stderr_line(line)
                        };
                        if let Err(e) = callback_result {
                            callback_error = Some(e);
                            break;
                        }
                    }

                    if capture_output {
                        let dst = if is_out { &mut stdout } else { &mut stderr };
                        dst.extend(new_lines);
                    }

                    data.drain(..idx);
                    *pos = 0;
                })?;
                let status = child.wait();
                if let Some(argfile) = argfile {
                    close_tempfile_and_log_error(argfile);
                }
                status
            })()
            .with_context(|| ProcessError::could_not_execute(self))?;
            let output = Output {
                status,
                stdout,
                stderr,
            };

            {
                let to_print = if capture_output { Some(&output) } else { None };
                if let Some(e) = callback_error {
                    let cx = ProcessError::new(
                        &format!("failed to parse process output: {}", self),
                        Some(output.status),
                        to_print,
                    );
                    bail!(anyhow::Error::new(cx).context(e));
                } else if !output.status.success() {
                    bail!(ProcessError::new(
                        &format!("process didn't exit successfully: {}", self),
                        Some(output.status),
                        to_print,
                    ));
                }
            }

            Ok(output)
        }

        /// Builds the command with an `@<path>` argfile that contains all the
        /// arguments. This is primarily served for rustc/rustdoc command family.
        fn build_command_with_argfile(&self) -> io::Result<(Command, NamedTempFile)> {
            use std::io::Write as _;

            let mut tmp = tempfile::Builder::new()
                .prefix("cargo-argfile.")
                .tempfile()?;

            let mut arg = OsString::from("@");
            arg.push(tmp.path());
            let mut cmd = self.build_command_without_args();
            cmd.arg(arg);
            log::debug!("created argfile at {} for {self}", tmp.path().display());

            let cap = self.get_args().map(|arg| arg.len() + 1).sum::<usize>();
            let mut buf = Vec::with_capacity(cap);
            for arg in &self.args {
                let arg = arg.to_str().ok_or_else(|| {
                    io::Error::new(
                        io::ErrorKind::Other,
                        format!(
                            "argument for argfile contains invalid UTF-8 characters: `{}`",
                            arg.to_string_lossy()
                        ),
                    )
                })?;
                if arg.contains('\n') {
                    return Err(io::Error::new(
                        io::ErrorKind::Other,
                        format!("argument for argfile contains newlines: `{arg}`"),
                    ));
                }
                writeln!(buf, "{arg}")?;
            }
            tmp.write_all(&mut buf)?;
            Ok((cmd, tmp))
        }

        /// Builds a command from `ProcessBuilder` for everything but not `args`.
        fn build_command_without_args(&self) -> Command {
            let mut command = {
                let mut iter = self.wrappers.iter().rev().chain(once(&self.program));
                let mut cmd = Command::new(iter.next().expect("at least one `program` exists"));
                cmd.args(iter);
                cmd
            };
            if let Some(cwd) = self.get_cwd() {
                command.current_dir(cwd);
            }
            for (k, v) in &self.env {
                match *v {
                    Some(ref v) => {
                        command.env(k, v);
                    }
                    None => {
                        command.env_remove(k);
                    }
                }
            }
            if let Some(ref c) = self.jobserver {
                c.configure(&mut command);
            }
            command
        }

        /// Converts `ProcessBuilder` into a `std::process::Command`, and handles
        /// the jobserver, if present.
        ///
        /// Note that this method doesn't take argfile fallback into account. The
        /// caller should handle it by themselves.
        pub fn build_command(&self) -> Command {
            let mut command = self.build_command_without_args();
            for arg in &self.args {
                command.arg(arg);
            }
            command
        }

        /// Wraps an existing command with the provided wrapper, if it is present and valid.
        ///
        /// # Examples
        ///
        /// ```rust
        /// use cargo_util::ProcessBuilder;
        /// // Running this would execute `rustc`
        /// let cmd = ProcessBuilder::new("rustc");
        ///
        /// // Running this will execute `sccache rustc`
        /// let cmd = cmd.wrapped(Some("sccache"));
        /// ```
        pub fn wrapped(mut self, wrapper: Option<impl AsRef<OsStr>>) -> Self {
            if let Some(wrapper) = wrapper.as_ref() {
                let wrapper = wrapper.as_ref();
                if !wrapper.is_empty() {
                    self.wrappers.push(wrapper.to_os_string());
                }
            }
            self
        }
    }

    /// Forces the command to use `@path` argfile.
    ///
    /// You should set `__CARGO_TEST_FORCE_ARGFILE` to enable this.
    fn debug_force_argfile(retry_enabled: bool) -> bool {
        cfg!(debug_assertions) && env::var("__CARGO_TEST_FORCE_ARGFILE").is_ok() && retry_enabled
    }

    /// Creates new pipes for stderr, stdout, and optionally stdin.
    fn piped(cmd: &mut Command, pipe_stdin: bool) -> &mut Command {
        cmd.stdout(Stdio::piped())
            .stderr(Stdio::piped())
            .stdin(if pipe_stdin {
                Stdio::piped()
            } else {
                Stdio::null()
            })
    }

    fn close_tempfile_and_log_error(file: NamedTempFile) {
        file.close().unwrap_or_else(|e| {
            log::warn!("failed to close temporary file: {e}");
        });
    }

    #[cfg(unix)]
    mod imp {
        use super::{close_tempfile_and_log_error, debug_force_argfile, ProcessBuilder, ProcessError};
        use anyhow::Result;
        use std::io;
        use std::os::unix::process::CommandExt;

        pub fn exec_replace(process_builder: &ProcessBuilder) -> Result<()> {
            let mut error;
            let mut file = None;
            if debug_force_argfile(process_builder.retry_with_argfile) {
                let (mut command, argfile) = process_builder.build_command_with_argfile()?;
                file = Some(argfile);
                error = command.exec()
            } else {
                let mut command = process_builder.build_command();
                error = command.exec();
                if process_builder.should_retry_with_argfile(&error) {
                    let (mut command, argfile) = process_builder.build_command_with_argfile()?;
                    file = Some(argfile);
                    error = command.exec()
                }
            }
            if let Some(file) = file {
                close_tempfile_and_log_error(file);
            }

            Err(anyhow::Error::from(error).context(ProcessError::new(
                &format!("could not execute process {}", process_builder),
                None,
                None,
            )))
        }

        pub fn command_line_too_big(err: &io::Error) -> bool {
            err.raw_os_error() == Some(libc::E2BIG)
        }
    }

    #[cfg(windows)]
    mod imp {
        use super::{ProcessBuilder, ProcessError};
        use anyhow::Result;
        use std::io;
        use windows_sys::Win32::Foundation::{BOOL, FALSE, TRUE};
        use windows_sys::Win32::System::Console::SetConsoleCtrlHandler;

        unsafe extern "system" fn ctrlc_handler(_: u32) -> BOOL {
            // Do nothing; let the child process handle it.
            TRUE
        }

        pub fn exec_replace(process_builder: &ProcessBuilder) -> Result<()> {
            unsafe {
                if SetConsoleCtrlHandler(Some(ctrlc_handler), TRUE) == FALSE {
                    return Err(ProcessError::new("Could not set Ctrl-C handler.", None, None).into());
                }
            }

            // Just execute the process as normal.
            process_builder.exec()
        }

        pub fn command_line_too_big(err: &io::Error) -> bool {
            use windows_sys::Win32::Foundation::ERROR_FILENAME_EXCED_RANGE;
            err.raw_os_error() == Some(ERROR_FILENAME_EXCED_RANGE as i32)
        }
    }

    #[cfg(test)]
    mod tests {
        use super::ProcessBuilder;
        use std::fs;

        #[test]
        fn argfile_build_succeeds() {
            let mut cmd = ProcessBuilder::new("echo");
            cmd.args(["foo", "bar"].as_slice());
            let (cmd, argfile) = cmd.build_command_with_argfile().unwrap();

            assert_eq!(cmd.get_program(), "echo");
            let cmd_args: Vec<_> = cmd.get_args().map(|s| s.to_str().unwrap()).collect();
            assert_eq!(cmd_args.len(), 1);
            assert!(cmd_args[0].starts_with("@"));
            assert!(cmd_args[0].contains("cargo-argfile."));

            let buf = fs::read_to_string(argfile.path()).unwrap();
            assert_eq!(buf, "foo\nbar\n");
        }

        #[test]
        fn argfile_build_fails_if_arg_contains_newline() {
            let mut cmd = ProcessBuilder::new("echo");
            cmd.arg("foo\n");
            let err = cmd.build_command_with_argfile().unwrap_err();
            assert_eq!(
                err.to_string(),
                "argument for argfile contains newlines: `foo\n`"
            );
        }

        #[test]
        fn argfile_build_fails_if_arg_contains_invalid_utf8() {
            let mut cmd = ProcessBuilder::new("echo");

            #[cfg(windows)]
            let invalid_arg = {
                use std::os::windows::prelude::*;
                std::ffi::OsString::from_wide(&[0x0066, 0x006f, 0xD800, 0x006f])
            };

            #[cfg(unix)]
            let invalid_arg = {
                use std::os::unix::ffi::OsStrExt;
                std::ffi::OsStr::from_bytes(&[0x66, 0x6f, 0x80, 0x6f]).to_os_string()
            };

            cmd.arg(invalid_arg);
            let err = cmd.build_command_with_argfile().unwrap_err();
            assert_eq!(
                err.to_string(),
                "argument for argfile contains invalid UTF-8 characters: `fo�o`"
            );
        }
    }