rust/hgcli/build.rs

commit: move sorting of added and removed files list to lower level

localrepo.commitctx() has lists of all changed files, as well as lists
of added and removed files. The list of all files is unsorted and
changelog.add() will sort it. Let's also sort the lists of added and
removed files at a lower level (manifestrevlog.add()) for
consistency. It also seems safer to do it there, just before we write
them to the store. That way other callers won't be able to create
invalid commits (or whatever the consequence is) by passing in
unsorted lists. Also, alternative storages may not care that the lists
are sorted. I don't think this will be a performance problem (someone
should have fixed the sorting in changelog.add() if it were).

Differential Revision: https://phab.mercurial-scm.org/D6390

// build.rs -- Configure build environment for `hgcli` Rust package.
//
// Copyright 2017 Gregory Szorc <[e-mail]>
//
// This software may be used and distributed according to the terms of the
// GNU General Public License version 2 or any later version.

use std::collections::HashMap;
use std::env;
use std::path::Path;
use std::process::Command;

struct PythonConfig {
    python: String,
    config: HashMap<String, String>,
}

fn get_python_config() -> PythonConfig {
    // The python27-sys crate exports a Cargo variable defining the full
    // path to the interpreter being used.
    let python = env::var("DEP_PYTHON27_PYTHON_INTERPRETER").expect(
        "Missing DEP_PYTHON27_PYTHON_INTERPRETER; bad python27-sys crate?",
    );

    if !Path::new(&python).exists() {
        panic!(
            "Python interpreter {} does not exist; this should never happen",
            python
        );
    }

    // This is a bit hacky but it gets the job done.
    let separator = "SEPARATOR STRING";

    let script = "import sysconfig; \
c = sysconfig.get_config_vars(); \
print('SEPARATOR STRING'.join('%s=%s' % i for i in c.items()))";

    let mut command = Command::new(&python);
    command.arg("-c").arg(script);

    let out = command.output().unwrap();

    if !out.status.success() {
        panic!(
            "python script failed: {}",
            String::from_utf8_lossy(&out.stderr)
        );
    }

    let stdout = String::from_utf8_lossy(&out.stdout);
    let mut m = HashMap::new();

    for entry in stdout.split(separator) {
        let mut parts = entry.splitn(2, "=");
        let key = parts.next().unwrap();
        let value = parts.next().unwrap();
        m.insert(String::from(key), String::from(value));
    }

    PythonConfig {
        python: python,
        config: m,
    }
}

#[cfg(not(target_os = "windows"))]
fn have_shared(config: &PythonConfig) -> bool {
    match config.config.get("Py_ENABLE_SHARED") {
        Some(value) => value == "1",
        None => false,
    }
}

#[cfg(target_os = "windows")]
fn have_shared(config: &PythonConfig) -> bool {
    use std::path::PathBuf;

    // python27.dll should exist next to python2.7.exe.
    let mut dll = PathBuf::from(&config.python);
    dll.pop();
    dll.push("python27.dll");

    return dll.exists();
}

const REQUIRED_CONFIG_FLAGS: [&str; 2] = ["Py_USING_UNICODE", "WITH_THREAD"];

fn main() {
    let config = get_python_config();

    println!("Using Python: {}", config.python);
    println!("cargo:rustc-env=PYTHON_INTERPRETER={}", config.python);

    let prefix = config.config.get("prefix").unwrap();

    println!("Prefix: {}", prefix);

    // TODO Windows builds don't expose these config flags. Figure out another
    // way.
    #[cfg(not(target_os = "windows"))]
    for key in REQUIRED_CONFIG_FLAGS.iter() {
        let result = match config.config.get(*key) {
            Some(value) => value == "1",
            None => false,
        };

        if !result {
            panic!("Detected Python requires feature {}", key);
        }
    }

    // We need a Python shared library.
    if !have_shared(&config) {
        panic!("Detected Python lacks a shared library, which is required");
    }

    let ucs4 = match config.config.get("Py_UNICODE_SIZE") {
        Some(value) => value == "4",
        None => false,
    };

    if !ucs4 {
        #[cfg(not(target_os = "windows"))]
        panic!("Detected Python doesn't support UCS-4 code points");
    }
}