build.rs/src/dvcs.rs

use std::process::Command;
use std::path::{Path,PathBuf};

pub fn from_setting(setting: Option<String>) -> Backend {
    // Git is the default setting until further notice
    setting.map_or(Backend::Git, |name| match name.as_ref() {
        "git" => Backend::Git,
        "mercurial" => Backend::Mercurial,
        _ => Backend::Unknown(name.to_string())
    })
}

#[derive(Debug)]
pub enum Backend {
    Git,
    Mercurial,
    Unknown(String),
}

#[derive(Debug)]
pub struct Repo {
    pub backend: Backend,
    pub source: String,
    pub dest: PathBuf,
    pub subupdates: bool,
}

impl Repo {
    pub fn new(backend: Backend, source: &str, dest: &Path, subupdates: bool) -> Repo {
        Repo {
            backend,
            source: source.to_string(),
            dest: dest.to_path_buf(),
            subupdates
        }
    }

    pub fn branch(&self) -> String {
        match &self.backend {
            Backend::Git => {
                let output = Command::new("git")
                    .arg("rev-parse")
                    .arg("--abbrev-ref")
                    .arg("HEAD")
                    .output().expect("WTF");
                if !output.status.success() {
                    panic!("Corrupted git repository???");
                }
                String::from_utf8(output.stdout).unwrap().trim().to_string()
            },
            Backend::Mercurial => {
                unreachable!("UNIMPLEMENTED!");
            },
            Backend::Unknown(name) => {
                panic!("Uknown backend: {}. Cannot find ranch", name);
            },
        }
    }

    pub fn clone(&self) -> bool {
        match &self.backend {
            Backend::Git => {
                let status = Command::new("git")
                    .arg("clone")
                    .arg("--recursive")
                    .arg(&self.source)
                    .arg(&self.dest)
                    .status().expect("PROCESS ERROR!");
                status.success()
            },
            Backend::Mercurial => {
                unreachable!("Unimplemented");
            },
            Backend::Unknown(name) => {
                eprintln!("Unknown DVCS: {}", name);
                false
            }
        }
    }

    pub fn checkout(&self, target: &str) -> bool {
        println!("CHECKOUT TO {}", target);
        match &self.backend {
            Backend::Git => {
                let status = Command::new("git")
                    .arg("checkout")
                    .arg(target)
                    .status().expect("PROCESS ERROR!");
                status.success()
            },
            Backend::Mercurial => {
                unreachable!("UNIMPLEMENTED");
            },
            Backend::Unknown(name) => {
                eprintln!("Unknown DVCS: {}", name);
                false
            }
        }
    }

    pub fn has_updates(&self) -> bool {
        match &self.backend {
            Backend::Git => {
                // Refresh remote
                if !Command::new("git")
                    .arg("fetch")
                    .arg("--quiet")
                    .arg("origin")
                    .status().expect("WTF").success() {
                    // FAILED, no internet??
                    eprintln!("Fetching updates failed");
                    return false;
                }
                let branch = self.branch();
                if Command::new("git")
                    .arg("diff")
                    .arg("--quiet")
                    .arg(format!("remotes/origin/{}", &branch))
                    .status().expect("WTF").success() {
                    // Command succeeeded, no updates
                    return false;
                }
                // Updates
                return true;
            },
            Backend::Mercurial => {
                unreachable!("unimplemented");
            },
            Backend::Unknown(name) => {
                eprintln!("Unknown DVCS:{}!", name);
                false
            }
        }
    }
    /*
    /// Runs an update on the repository in dest. Returns true
    /// when an update was performed, false otherwise
    pub fn update(&self, dest: &str) -> bool {
        match self {
            Backend::Git => {
                
            },
            Backend::Mercurial => {

            },
            Backend::Unknown(name) => {
                eprintln!("Unknown DVCS: {}", name);
                false
            }
        }
    }*/
}