gix-filter 0.35.0

A crate of the gitoxide project implementing git filters
Documentation 
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use std::process::Stdio;

use gix_error::ExnMessageResult;

use bstr::{BStr, BString};

use crate::{
    Driver, driver,
    driver::{Operation, Process, State, process, substitute_f_parameter},
};

/// Lifecycle
impl State {
    /// Obtain a process as defined in `driver` suitable for a given `operation. `rela_path` may be used to substitute the current
    /// file for use in the invoked `SingleFile` process.
    ///
    /// Note that if a long-running process is defined, the `operation` isn't relevant and capabilities are to be checked by the caller.
    pub fn maybe_launch_process(
        &mut self,
        driver: &Driver,
        operation: Operation,
        rela_path: &BStr,
    ) -> ExnMessageResult<Option<Process<'_>>> {
        match driver.process.as_ref() {
            Some(process) => {
                let client = match self.running.remove(process) {
                    Some(c) => c,
                    None => {
                        let (child, cmd) = spawn_driver(process.clone(), &self.context)?;
                        use gix_error::{ResultExt, message};
                        process::Client::handshake(child, "git-filter", &[2], &["clean", "smudge", "delay"])
                            .or_raise(|| message!("Process handshake with command {cmd:?} failed"))?
                    }
                };

                // TODO: find a way to not have to do this 'borrow-dance'.
                // this strangeness is to workaround the borrowchecker, who otherwise won't let us return a reader. Quite sad :/.
                // One would want to `get_mut()` or insert essentially, but it won't work.
                self.running.insert(process.clone(), client);
                let client = self.running.get_mut(process).expect("just inserted");

                Ok(Some(Process::MultiFile {
                    client,
                    key: driver::Key(process.to_owned()),
                }))
            }
            None => {
                let cmd = match operation {
                    Operation::Clean => driver
                        .clean
                        .as_ref()
                        .map(|cmd| substitute_f_parameter(cmd.as_ref(), rela_path)),

                    Operation::Smudge => driver
                        .smudge
                        .as_ref()
                        .map(|cmd| substitute_f_parameter(cmd.as_ref(), rela_path)),
                };

                let cmd = match cmd {
                    Some(cmd) => cmd,
                    None => return Ok(None),
                };

                let (child, command) = spawn_driver(cmd, &self.context)?;
                Ok(Some(Process::SingleFile { child, command }))
            }
        }
    }
}

fn spawn_driver(
    cmd: BString,
    context: &gix_command::Context,
) -> ExnMessageResult<(std::process::Child, std::process::Command)> {
    let mut cmd: std::process::Command = gix_command::prepare(gix_path::from_bstr(cmd).into_owned())
        .command_may_be_shell_script()
        .with_context(context.clone())
        .stdin(Stdio::piped())
        .stdout(Stdio::piped())
        .stderr(Stdio::inherit())
        .into();
    gix_trace::debug!(cmd = ?cmd, "launching filter driver");
    let child = match cmd.spawn() {
        Ok(child) => child,
        Err(err) => {
            use gix_error::ErrorExt;
            return Err(err.and_raise(gix_error::message!("Failed to spawn driver: {cmd:?}")));
        }
    };
    Ok((child, cmd))
}