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#[cfg(unix)] mod os { pub const NULL_DEVICE: &str = "/dev/null"; pub const SHELL: [&str; 2] = ["sh", "-c"]; } #[cfg(windows)] mod os { pub const NULL_DEVICE: &str = "nul"; pub const SHELL: [&str; 2] = ["cmd.exe", "/c"]; } pub use self::exec::{CaptureData, Exec, NullFile}; pub use self::os::*; pub use self::pipeline::Pipeline; #[cfg(unix)] pub use exec::unix; mod exec { use std::ffi::{OsStr, OsString}; use std::fmt; use std::fs::{File, OpenOptions}; use std::io::{self, Read, Write}; use std::ops::BitOr; use std::path::Path; use crate::communicate::Communicator; use crate::os_common::ExitStatus; use crate::popen::{Popen, PopenConfig, Redirection, Result as PopenResult}; use super::os::*; use super::Pipeline; /// A builder for [`Popen`] instances, providing control and /// convenience methods. /// /// `Exec` provides a builder API for [`Popen::create`], and /// includes convenience methods for capturing the output, and for /// connecting subprocesses into pipelines. /// /// # Examples /// /// Execute an external command and wait for it to complete: /// /// ```no_run /// # use subprocess::*; /// # fn dummy() -> Result<()> { /// # let dirname = "some_dir"; /// let exit_status = Exec::cmd("umount").arg(dirname).join()?; /// # Ok(()) /// # } /// ``` /// /// Execute the command using the OS shell, like C's `system`: /// /// ```no_run /// # use subprocess::*; /// # fn dummy() -> Result<()> { /// Exec::shell("shutdown -h now").join()?; /// # Ok(()) /// # } /// ``` /// /// Start a subprocess and obtain its output as a `Read` trait object, /// like C's `popen`: /// /// ``` /// # use subprocess::*; /// # fn dummy() -> Result<()> { /// let stream = Exec::cmd("ls").stream_stdout()?; /// // call stream.read_to_string, construct io::BufReader(stream), etc. /// # Ok(()) /// # } /// ``` /// /// Capture the output of a command: /// /// ``` /// # use subprocess::*; /// # fn dummy() -> Result<()> { /// let out = Exec::cmd("ls") /// .stdout(Redirection::Pipe) /// .capture()? /// .stdout_str(); /// # Ok(()) /// # } /// ``` /// /// Redirect errors to standard output, and capture both in a single stream: /// /// ``` /// # use subprocess::*; /// # fn dummy() -> Result<()> { /// let out_and_err = Exec::cmd("ls") /// .stdout(Redirection::Pipe) /// .stderr(Redirection::Merge) /// .capture()? /// .stdout_str(); /// # Ok(()) /// # } /// ``` /// /// Provide input to the command and read its output: /// /// ``` /// # use subprocess::*; /// # fn dummy() -> Result<()> { /// let out = Exec::cmd("sort") /// .stdin("b\nc\na\n") /// .stdout(Redirection::Pipe) /// .capture()? /// .stdout_str(); /// assert!(out == "a\nb\nc\n"); /// # Ok(()) /// # } /// ``` /// /// [`Popen`]: struct.Popen.html /// [`Popen::create`]: struct.Popen.html#method.create #[must_use] pub struct Exec { command: OsString, args: Vec<OsString>, config: PopenConfig, stdin_data: Option<Vec<u8>>, } impl Exec { /// Constructs a new `Exec`, configured to run `command`. /// /// The command will be run directly in the OS, without an /// intervening shell. To run it through a shell, use /// [`Exec::shell`] instead. /// /// By default, the command will be run without arguments, and /// none of the standard streams will be modified. /// /// [`Exec::shell`]: struct.Exec.html#method.shell pub fn cmd(command: impl AsRef<OsStr>) -> Exec { Exec { command: command.as_ref().to_owned(), args: vec![], config: PopenConfig::default(), stdin_data: None, } } /// Constructs a new `Exec`, configured to run `cmdstr` with /// the system shell. /// /// `subprocess` never spawns shells without an explicit /// request. This command requests the shell to be used; on /// Unix-like systems, this is equivalent to /// `Exec::cmd("sh").arg("-c").arg(cmdstr)`. On Windows, it /// runs `Exec::cmd("cmd.exe").arg("/c")`. /// /// `shell` is useful for porting code that uses the C /// `system` function, which also spawns a shell. /// /// When invoking this function, be careful not to interpolate /// arguments into the string run by the shell, such as /// `Exec::shell(format!("sort {}", filename))`. Such code is /// prone to errors and, if `filename` comes from an untrusted /// source, to shell injection attacks. Instead, use /// `Exec::cmd("sort").arg(filename)`. pub fn shell(cmdstr: impl AsRef<OsStr>) -> Exec { Exec::cmd(SHELL[0]).args(&SHELL[1..]).arg(cmdstr) } /// Appends `arg` to argument list. pub fn arg(mut self, arg: impl AsRef<OsStr>) -> Exec { self.args.push(arg.as_ref().to_owned()); self } /// Extends the argument list with `args`. pub fn args(mut self, args: &[impl AsRef<OsStr>]) -> Exec { self.args.extend(args.iter().map(|x| x.as_ref().to_owned())); self } /// Specifies that the process is initially detached. /// /// A detached process means that we will not wait for the /// process to finish when the object that owns it goes out of /// scope. pub fn detached(mut self) -> Exec { self.config.detached = true; self } fn ensure_env(&mut self) { if self.config.env.is_none() { self.config.env = Some(PopenConfig::current_env()); } } /// Clears the environment of the subprocess. /// /// When this is invoked, the subprocess will not inherit the /// environment of this process. pub fn env_clear(mut self) -> Exec { self.config.env = Some(Vec::new()); self } /// Sets an environment variable in the child process. /// /// If the same variable is set more than once, the last value /// is used. /// /// Other environment variables are by default inherited from /// the current process. If this is undesirable, call /// `env_clear` first. pub fn env(mut self, key: impl AsRef<OsStr>, value: impl AsRef<OsStr>) -> Exec { self.ensure_env(); self.config .env .as_mut() .unwrap() .push((key.as_ref().to_owned(), value.as_ref().to_owned())); self } /// Sets multiple environment variables in the child process. /// /// The keys and values of the variables are specified by the /// slice. If the same variable is set more than once, the /// last value is used. /// /// Other environment variables are by default inherited from /// the current process. If this is undesirable, call /// `env_clear` first. pub fn env_extend(mut self, vars: &[(impl AsRef<OsStr>, impl AsRef<OsStr>)]) -> Exec { self.ensure_env(); { let envvec = self.config.env.as_mut().unwrap(); for &(ref k, ref v) in vars { envvec.push((k.as_ref().to_owned(), v.as_ref().to_owned())); } } self } /// Removes an environment variable from the child process. /// /// Other environment variables are inherited by default. pub fn env_remove(mut self, key: impl AsRef<OsStr>) -> Exec { self.ensure_env(); self.config .env .as_mut() .unwrap() .retain(|&(ref k, ref _v)| k != key.as_ref()); self } /// Specifies the current working directory of the child process. /// /// If unspecified, the current working directory is inherited /// from the parent. pub fn cwd(mut self, dir: impl AsRef<Path>) -> Exec { self.config.cwd = Some(dir.as_ref().as_os_str().to_owned()); self } /// Specifies how to set up the standard input of the child process. /// /// Argument can be: /// /// * a [`Redirection`]; /// * a `File`, which is a shorthand for `Redirection::File(file)`; /// * a `Vec<u8>` or `&str`, which will set up a `Redirection::Pipe` /// for stdin, making sure that `capture` feeds that data into the /// standard input of the subprocess; /// * [`NullFile`], which will redirect the standard input to read from /// `/dev/null`. /// /// [`Redirection`]: struct.Redirection.html /// [`NullFile`]: struct.NullFile.html pub fn stdin(mut self, stdin: impl Into<InputRedirection>) -> Exec { match (&self.config.stdin, stdin.into()) { (&Redirection::None, InputRedirection::AsRedirection(new)) => { self.config.stdin = new } (&Redirection::Pipe, InputRedirection::AsRedirection(Redirection::Pipe)) => (), (&Redirection::None, InputRedirection::FeedData(data)) => { self.config.stdin = Redirection::Pipe; self.stdin_data = Some(data); } (_, _) => panic!("stdin is already set"), } self } /// Specifies how to set up the standard output of the child process. /// /// Argument can be: /// /// * a [`Redirection`]; /// * a `File`, which is a shorthand for `Redirection::File(file)`; /// * [`NullFile`], which will redirect the standard output to go to /// `/dev/null`. /// /// [`Redirection`]: struct.Redirection.html /// [`NullFile`]: struct.NullFile.html pub fn stdout(mut self, stdout: impl Into<OutputRedirection>) -> Exec { match (&self.config.stdout, stdout.into().into_redirection()) { (&Redirection::None, new) => self.config.stdout = new, (&Redirection::Pipe, Redirection::Pipe) => (), (_, _) => panic!("stdout is already set"), } self } /// Specifies how to set up the standard error of the child process. /// /// Argument can be: /// /// * a [`Redirection`]; /// * a `File`, which is a shorthand for `Redirection::File(file)`; /// * [`NullFile`], which will redirect the standard error to go to /// `/dev/null`. /// /// [`Redirection`]: struct.Redirection.html /// [`NullFile`]: struct.NullFile.html pub fn stderr(mut self, stderr: impl Into<OutputRedirection>) -> Exec { match (&self.config.stderr, stderr.into().into_redirection()) { (&Redirection::None, new) => self.config.stderr = new, (&Redirection::Pipe, Redirection::Pipe) => (), (_, _) => panic!("stderr is already set"), } self } fn check_no_stdin_data(&self, meth: &str) { if self.stdin_data.is_some() { panic!("{} called with input data specified", meth); } } // Terminators /// Starts the process, returning a `Popen` for the running process. pub fn popen(mut self) -> PopenResult<Popen> { self.check_no_stdin_data("popen"); self.args.insert(0, self.command); let p = Popen::create(&self.args, self.config)?; Ok(p) } /// Starts the process, waits for it to finish, and returns /// the exit status. /// /// This method will wait for as long as necessary for the process to /// finish. If a timeout is needed, use /// `<...>.detached().popen()?.wait_timeout(...)` instead. pub fn join(self) -> PopenResult<ExitStatus> { self.check_no_stdin_data("join"); self.popen()?.wait() } /// Starts the process and returns a value implementing the `Read` /// trait that reads from the standard output of the child process. /// /// This will automatically set up /// `stdout(Redirection::Pipe)`, so it is not necessary to do /// that beforehand. /// /// When the trait object is dropped, it will wait for the /// process to finish. If this is undesirable, use /// `detached()`. pub fn stream_stdout(self) -> PopenResult<impl Read> { self.check_no_stdin_data("stream_stdout"); let p = self.stdout(Redirection::Pipe).popen()?; Ok(ReadOutAdapter(p)) } /// Starts the process and returns a value implementing the `Read` /// trait that reads from the standard error of the child process. /// /// This will automatically set up /// `stderr(Redirection::Pipe)`, so it is not necessary to do /// that beforehand. /// /// When the trait object is dropped, it will wait for the /// process to finish. If this is undesirable, use /// `detached()`. pub fn stream_stderr(self) -> PopenResult<impl Read> { self.check_no_stdin_data("stream_stderr"); let p = self.stderr(Redirection::Pipe).popen()?; Ok(ReadErrAdapter(p)) } /// Starts the process and returns a value implementing the `Write` /// trait that writes to the standard input of the child process. /// /// This will automatically set up `stdin(Redirection::Pipe)`, /// so it is not necessary to do that beforehand. /// /// When the trait object is dropped, it will wait for the /// process to finish. If this is undesirable, use /// `detached()`. pub fn stream_stdin(self) -> PopenResult<impl Write> { self.check_no_stdin_data("stream_stdin"); let p = self.stdin(Redirection::Pipe).popen()?; Ok(WriteAdapter(p)) } fn setup_communicate(mut self) -> PopenResult<(Communicator, Popen)> { let stdin_data = self.stdin_data.take(); if let (&Redirection::None, &Redirection::None) = (&self.config.stdout, &self.config.stderr) { self = self.stdout(Redirection::Pipe); } let mut p = self.popen()?; Ok((p.communicate_start(stdin_data), p)) } /// Starts the process and returns a `Communicator` handle. /// /// This is a lower-level API that offers more choice in how /// communication is performed, such as read size limit and timeout, /// equivalent to [`Popen::communicate`]. /// /// Unlike `capture()`, this method doesn't wait for the process to /// finish, effectively detaching it. /// /// [`Popen::communicate`]: struct.Popen.html#method.communicate pub fn communicate(self) -> PopenResult<Communicator> { let comm = self.detached().setup_communicate()?.0; Ok(comm) } /// Starts the process, collects its output, and waits for it /// to finish. /// /// The return value provides the standard output and standard /// error as bytes or optionally strings, as well as the exit /// status. /// /// Unlike `Popen::communicate`, this method actually waits /// for the process to finish, rather than simply waiting for /// its standard streams to close. If this is undesirable, /// use `detached()`. pub fn capture(self) -> PopenResult<CaptureData> { let (mut comm, mut p) = self.setup_communicate()?; let (maybe_out, maybe_err) = comm.read()?; Ok(CaptureData { stdout: maybe_out.unwrap_or_else(Vec::new), stderr: maybe_err.unwrap_or_else(Vec::new), exit_status: p.wait()?, }) } /// Show Exec as command-line string quoted in the Unix style. pub fn to_cmdline_lossy(&self) -> String { fn nice_char(c: char) -> bool { match c { '-' | '_' | '.' | ',' | '/' => true, c if c.is_ascii_alphanumeric() => true, _ => false, } } fn write_quoted(out: &mut String, s: &str) { if !s.chars().all(nice_char) { out.push_str(&format!("'{}'", s.replace("'", r#"'\''"#))); } else { out.push_str(s); } } let mut out = String::new(); write_quoted(&mut out, &self.command.to_string_lossy()); for arg in &self.args { out.push(' '); write_quoted(&mut out, &arg.to_string_lossy()); } out } } impl Clone for Exec { /// Returns a copy of the value. /// /// This method is guaranteed not to fail as long as none of /// the `Redirection` values contain a `Redirection::File` /// variant. If a redirection to `File` is present, cloning /// that field will use `File::try_clone` method, which /// duplicates a file descriptor and can (but is not likely /// to) fail. In that scenario, `Exec::clone` panics. fn clone(&self) -> Exec { Exec { command: self.command.clone(), args: self.args.clone(), config: self.config.try_clone().unwrap(), stdin_data: self.stdin_data.as_ref().cloned(), } } } impl BitOr for Exec { type Output = Pipeline; /// Create a `Pipeline` from `self` and `rhs`. fn bitor(self, rhs: Exec) -> Pipeline { Pipeline::new(self, rhs) } } impl fmt::Debug for Exec { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { write!(f, "Exec {{ {} }}", self.to_cmdline_lossy()) } } #[derive(Debug)] struct ReadOutAdapter(Popen); impl Read for ReadOutAdapter { fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> { self.0.stdout.as_mut().unwrap().read(buf) } } #[derive(Debug)] struct ReadErrAdapter(Popen); impl Read for ReadErrAdapter { fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> { self.0.stderr.as_mut().unwrap().read(buf) } } #[derive(Debug)] struct WriteAdapter(Popen); impl Write for WriteAdapter { fn write(&mut self, buf: &[u8]) -> io::Result<usize> { self.0.stdin.as_mut().unwrap().write(buf) } fn flush(&mut self) -> io::Result<()> { self.0.stdin.as_mut().unwrap().flush() } } // We must implement Drop in order to close the stream. The typical // use case for stream_stdin() is a process that reads something from // stdin. WriteAdapter going out of scope invokes Popen::drop(), // which waits for the process to exit. Without closing stdin, this // deadlocks because the child process hangs reading its stdin. impl Drop for WriteAdapter { fn drop(&mut self) { self.0.stdin.take(); } } /// Data captured by [`Exec::capture`] and [`Pipeline::capture`]. /// /// [`Exec::capture`]: struct.Exec.html#method.capture /// [`Pipeline::capture`]: struct.Pipeline.html#method.capture pub struct CaptureData { /// Standard output as bytes. pub stdout: Vec<u8>, /// Standard error as bytes. pub stderr: Vec<u8>, /// Exit status. pub exit_status: ExitStatus, } impl CaptureData { /// Returns the standard output as string, converted from bytes using /// `String::from_utf8_lossy`. pub fn stdout_str(&self) -> String { String::from_utf8_lossy(&self.stdout).into_owned() } /// Returns the standard error as string, converted from bytes using /// `String::from_utf8_lossy`. pub fn stderr_str(&self) -> String { String::from_utf8_lossy(&self.stderr).into_owned() } /// True if the exit status of the process or pipeline is 0. pub fn success(&self) -> bool { self.exit_status.success() } } pub enum InputRedirection { AsRedirection(Redirection), FeedData(Vec<u8>), } impl From<Redirection> for InputRedirection { fn from(r: Redirection) -> Self { if let Redirection::Merge = r { panic!("Redirection::Merge is only allowed for output streams"); } InputRedirection::AsRedirection(r) } } impl From<File> for InputRedirection { fn from(f: File) -> Self { InputRedirection::AsRedirection(Redirection::File(f)) } } /// Marker value for [`stdin`], [`stdout`], and [`stderr`] methods /// of [`Exec`] and [`Pipeline`]. /// /// Use of this value means that the corresponding stream should /// be redirected to the devnull device. /// /// [`stdin`]: struct.Exec.html#method.stdin /// [`stdout`]: struct.Exec.html#method.stdout /// [`stderr`]: struct.Exec.html#method.stderr /// [`Exec`]: struct.Exec.html /// [`Pipeline`]: struct.Pipeline.html #[derive(Debug)] pub struct NullFile; impl From<NullFile> for InputRedirection { fn from(_nf: NullFile) -> Self { let null_file = OpenOptions::new().read(true).open(NULL_DEVICE).unwrap(); InputRedirection::AsRedirection(Redirection::File(null_file)) } } impl From<Vec<u8>> for InputRedirection { fn from(v: Vec<u8>) -> Self { InputRedirection::FeedData(v) } } impl<'a> From<&'a str> for InputRedirection { fn from(s: &'a str) -> Self { InputRedirection::FeedData(s.as_bytes().to_vec()) } } #[derive(Debug)] pub struct OutputRedirection(Redirection); impl OutputRedirection { pub fn into_redirection(self) -> Redirection { self.0 } } impl From<Redirection> for OutputRedirection { fn from(r: Redirection) -> Self { OutputRedirection(r) } } impl From<File> for OutputRedirection { fn from(f: File) -> Self { OutputRedirection(Redirection::File(f)) } } impl From<NullFile> for OutputRedirection { fn from(_nf: NullFile) -> Self { let null_file = OpenOptions::new().write(true).open(NULL_DEVICE).unwrap(); OutputRedirection(Redirection::File(null_file)) } } #[cfg(unix)] pub mod unix { use super::Exec; pub trait ExecExt { fn setuid(self, uid: u32) -> Self; fn setgid(self, gid: u32) -> Self; } impl ExecExt for Exec { fn setuid(mut self, uid: u32) -> Exec { self.config.setuid = Some(uid); self } fn setgid(mut self, gid: u32) -> Exec { self.config.setgid = Some(gid); self } } } } mod pipeline { use std::fmt; use std::fs::File; use std::io::{self, Read, Write}; use std::ops::BitOr; use std::rc::Rc; use crate::communicate::{self, Communicator}; use crate::os_common::ExitStatus; use crate::popen::{Popen, Redirection, Result as PopenResult}; use super::exec::{CaptureData, Exec, InputRedirection, OutputRedirection}; /// A builder for multiple [`Popen`] instances connected via /// pipes. /// /// A pipeline is a sequence of two or more [`Exec`] commands /// connected via pipes. Just like in a Unix shell pipeline, each /// command receives standard input from the previous command, and /// passes standard output to the next command. Optionally, the /// standard input of the first command can be provided from the /// outside, and the output of the last command can be captured. /// /// In most cases you do not need to create [`Pipeline`] instances /// directly; instead, combine [`Exec`] instances using the `|` /// operator which produces `Pipeline`. /// /// # Examples /// /// Execute a pipeline and return the exit status of the last command: /// /// ```no_run /// # use subprocess::*; /// # fn dummy() -> Result<()> { /// let exit_status = /// (Exec::shell("ls *.bak") | Exec::cmd("xargs").arg("rm")).join()?; /// # Ok(()) /// # } /// ``` /// /// Capture the pipeline's output: /// /// ```no_run /// # use subprocess::*; /// # fn dummy() -> Result<()> { /// let dir_checksum = { /// Exec::cmd("find . -type f") | Exec::cmd("sort") | Exec::cmd("sha1sum") /// }.capture()?.stdout_str(); /// # Ok(()) /// # } /// ``` /// /// [`Popen`]: struct.Popen.html /// [`Exec`]: struct.Exec.html /// [`Pipeline`]: struct.Pipeline.html #[must_use] pub struct Pipeline { cmds: Vec<Exec>, stdin: Redirection, stdout: Redirection, stderr_file: Option<File>, stdin_data: Option<Vec<u8>>, } impl Pipeline { /// Creates a new pipeline by combining two commands. /// /// Equivalent to `cmd1 | cmd2`. pub fn new(cmd1: Exec, cmd2: Exec) -> Pipeline { Pipeline { cmds: vec![cmd1, cmd2], stdin: Redirection::None, stdout: Redirection::None, stderr_file: None, stdin_data: None, } } /// Specifies how to set up the standard input of the first /// command in the pipeline. /// /// Argument can be: /// /// * a [`Redirection`]; /// * a `File`, which is a shorthand for `Redirection::File(file)`; /// * a `Vec<u8>` or `&str`, which will set up a `Redirection::Pipe` /// for stdin, making sure that `capture` feeds that data into the /// standard input of the subprocess. /// * `NullFile`, which will redirect the standard input to read from /// /dev/null. /// /// [`Redirection`]: struct.Redirection.html pub fn stdin(mut self, stdin: impl Into<InputRedirection>) -> Pipeline { match stdin.into() { InputRedirection::AsRedirection(r) => self.stdin = r, InputRedirection::FeedData(data) => { self.stdin = Redirection::Pipe; self.stdin_data = Some(data); } }; self } /// Specifies how to set up the standard output of the last /// command in the pipeline. /// /// Argument can be: /// /// * a [`Redirection`]; /// * a `File`, which is a shorthand for `Redirection::File(file)`; /// * `NullFile`, which will redirect the standard output to write to /// /dev/null. /// /// [`Redirection`]: struct.Redirection.html pub fn stdout(mut self, stdout: impl Into<OutputRedirection>) -> Pipeline { self.stdout = stdout.into().into_redirection(); self } /// Specifies a file to which to redirect the standard error of all /// the commands in the pipeline. /// /// It is useful for capturing the standard error of the pipeline as a /// whole. Unlike `stdout()`, which only affects the last command in /// the pipeline, this affects all commands. The difference is /// because standard output is piped from one command to the next, so /// only the output of the last command is "free". In contrast, the /// standard errors are not connected in any way. This is also the /// reason only a `File` is supported - it allows for efficient /// sharing of the same file by all commands. pub fn stderr_to(mut self, to: File) -> Pipeline { self.stderr_file = Some(to); self } fn check_no_stdin_data(&self, meth: &str) { if self.stdin_data.is_some() { panic!("{} called with input data specified", meth); } } // Terminators: /// Starts all commands in the pipeline, and returns a /// `Vec<Popen>` whose members correspond to running commands. /// /// If some command fails to start, the remaining commands /// will not be started, and the appropriate error will be /// returned. The commands that have already started will be /// waited to finish (but will probably exit immediately due /// to missing output), except for the ones for which /// `detached()` was called. This is equivalent to what the /// shell does. pub fn popen(mut self) -> PopenResult<Vec<Popen>> { self.check_no_stdin_data("popen"); assert!(self.cmds.len() >= 2); if let Some(stderr_to) = self.stderr_file { let stderr_to = Rc::new(stderr_to); self.cmds = self .cmds .into_iter() .map(|cmd| cmd.stderr(Redirection::RcFile(Rc::clone(&stderr_to)))) .collect(); } let first_cmd = self.cmds.drain(..1).next().unwrap(); self.cmds.insert(0, first_cmd.stdin(self.stdin)); let last_cmd = self.cmds.drain(self.cmds.len() - 1..).next().unwrap(); self.cmds.push(last_cmd.stdout(self.stdout)); let mut ret = Vec::<Popen>::new(); let cnt = self.cmds.len(); for (idx, mut runner) in self.cmds.into_iter().enumerate() { if idx != 0 { let prev_stdout = ret[idx - 1].stdout.take().unwrap(); runner = runner.stdin(prev_stdout); } if idx != cnt - 1 { runner = runner.stdout(Redirection::Pipe); } ret.push(runner.popen()?); } Ok(ret) } /// Starts the pipeline, waits for it to finish, and returns /// the exit status of the last command. pub fn join(self) -> PopenResult<ExitStatus> { self.check_no_stdin_data("join"); let mut v = self.popen()?; // Waiting on a pipeline waits for all commands, but // returns the status of the last one. This is how the // shells do it. If the caller needs more precise control // over which status is returned, they can call popen(). v.last_mut().unwrap().wait() } /// Starts the pipeline and returns a value implementing the `Read` /// trait that reads from the standard output of the last command. /// /// This will automatically set up /// `stdout(Redirection::Pipe)`, so it is not necessary to do /// that beforehand. /// /// When the trait object is dropped, it will wait for the /// pipeline to finish. If this is undesirable, use /// `detached()`. pub fn stream_stdout(self) -> PopenResult<impl Read> { self.check_no_stdin_data("stream_stdout"); let v = self.stdout(Redirection::Pipe).popen()?; Ok(ReadPipelineAdapter(v)) } /// Starts the pipeline and returns a value implementing the `Write` /// trait that writes to the standard input of the last command. /// /// This will automatically set up `stdin(Redirection::Pipe)`, /// so it is not necessary to do that beforehand. /// /// When the trait object is dropped, it will wait for the /// process to finish. If this is undesirable, use /// `detached()`. pub fn stream_stdin(self) -> PopenResult<impl Write> { self.check_no_stdin_data("stream_stdin"); let v = self.stdin(Redirection::Pipe).popen()?; Ok(WritePipelineAdapter(v)) } fn setup_communicate(mut self) -> PopenResult<(Communicator, Vec<Popen>)> { assert!(self.cmds.len() >= 2); let (err_read, err_write) = crate::popen::make_pipe()?; self = self.stderr_to(err_write); let stdin_data = self.stdin_data.take(); let mut v = self.stdout(Redirection::Pipe).popen()?; let vlen = v.len(); let comm = communicate::communicate( v[0].stdin.take(), v[vlen - 1].stdout.take(), Some(err_read), stdin_data, ); Ok((comm, v)) } /// Starts the pipeline and returns a `Communicator` handle. /// /// This is a lower-level API that offers more choice in how /// communication is performed, such as read size limit and timeout, /// equivalent to [`Popen::communicate`]. /// /// Unlike `capture()`, this method doesn't wait for the pipeline to /// finish, effectively detaching it. /// /// [`Popen::communicate`]: struct.Popen.html#method.communicate pub fn communicate(mut self) -> PopenResult<Communicator> { self.cmds = self.cmds.into_iter().map(|cmd| cmd.detached()).collect(); let comm = self.setup_communicate()?.0; Ok(comm) } /// Starts the pipeline, collects its output, and waits for all /// commands to finish. /// /// The return value provides the standard output of the last command, /// the combined standard error of all commands, and the exit status /// of the last command. The captured outputs can be accessed as /// bytes or strings. /// /// Unlike `Popen::communicate`, this method actually waits for the /// processes to finish, rather than simply waiting for the output to /// close. If this is undesirable, use `detached()`. pub fn capture(self) -> PopenResult<CaptureData> { let (mut comm, mut v) = self.setup_communicate()?; let (out, err) = comm.read()?; let out = out.unwrap_or_else(Vec::new); let err = err.unwrap(); let vlen = v.len(); let status = v[vlen - 1].wait()?; Ok(CaptureData { stdout: out, stderr: err, exit_status: status, }) } } impl Clone for Pipeline { /// Returns a copy of the value. /// /// This method is guaranteed not to fail as long as none of /// the `Redirection` values contain a `Redirection::File` /// variant. If a redirection to `File` is present, cloning /// that field will use `File::try_clone` method, which /// duplicates a file descriptor and can (but is not likely /// to) fail. In that scenario, `Exec::clone` panics. fn clone(&self) -> Pipeline { Pipeline { cmds: self.cmds.clone(), stdin: self.stdin.try_clone().unwrap(), stdout: self.stdout.try_clone().unwrap(), stderr_file: self.stderr_file.as_ref().map(|f| f.try_clone().unwrap()), stdin_data: self.stdin_data.clone(), } } } impl BitOr<Exec> for Pipeline { type Output = Pipeline; /// Append a command to the pipeline and return a new pipeline. fn bitor(mut self, rhs: Exec) -> Pipeline { self.cmds.push(rhs); self } } impl BitOr for Pipeline { type Output = Pipeline; /// Append a pipeline to the pipeline and return a new pipeline. fn bitor(mut self, rhs: Pipeline) -> Pipeline { self.cmds.extend(rhs.cmds); self.stdout = rhs.stdout; self } } impl fmt::Debug for Pipeline { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { let mut args = Vec::new(); for cmd in &self.cmds { args.push(cmd.to_cmdline_lossy()); } write!(f, "Pipeline {{ {} }}", args.join(" | ")) } } #[derive(Debug)] struct ReadPipelineAdapter(Vec<Popen>); impl Read for ReadPipelineAdapter { fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> { let last = self.0.last_mut().unwrap(); last.stdout.as_mut().unwrap().read(buf) } } #[derive(Debug)] struct WritePipelineAdapter(Vec<Popen>); impl WritePipelineAdapter { fn stdin(&mut self) -> &mut File { let first = self.0.first_mut().unwrap(); first.stdin.as_mut().unwrap() } } impl Write for WritePipelineAdapter { fn write(&mut self, buf: &[u8]) -> io::Result<usize> { self.stdin().write(buf) } fn flush(&mut self) -> io::Result<()> { self.stdin().flush() } } impl Drop for WritePipelineAdapter { // the same rationale as Drop for WriteAdapter fn drop(&mut self) { let first = &mut self.0[0]; first.stdin.take(); } } }