build.rs

#[macro_use]
extern crate diesel;

use diesel::prelude::*;
use diesel::Connection;
use quote::quote;
use std::env;
use std::fs::File;
use std::io::prelude::*;
use std::path::Path;
use walkdir::WalkDir;

#[allow(dead_code)]
mod sqlfunc {
    use diesel::sql_types::Text;
    sql_function!(fn markdown_to_fts(text: Text) -> Text);
    sql_function!(fn theme_from_str_hash(text: Text) -> Text);
}

fn main() {
    let out_dir = env::var("OUT_DIR").expect("cargo must set OUT_DIR");
    let db_path = Path::new(&out_dir).join("build.db");
    let db_path = db_path
        .to_str()
        .expect("Will only work for Unicode-representable paths");

    let _ignore_failure = std::fs::remove_file(db_path);

    let connection = SqliteConnection::establish(db_path)
        .unwrap_or_else(|_| panic!("Error esablishing a database connection to {}", db_path));

    // Integer is a dummy placeholder. Compiling fails when passing ().
    diesel::expression::sql_literal::sql::<diesel::sql_types::Integer>("PRAGMA foreign_keys = ON")
        .execute(&connection)
        .expect("Should be able to enable foreign keys");

    sqlfunc::markdown_to_fts::register_impl(&connection, |_: String| -> String { unreachable!() })
        .unwrap();
    sqlfunc::theme_from_str_hash::register_impl(&connection, |_: String| -> String {
        unreachable!()
    })
    .unwrap();

    diesel_migrations::run_pending_migrations(&connection).unwrap();

    let infer_schema_path = Path::new(&out_dir).join("infer_schema.rs");
    let mut file = File::create(infer_schema_path).expect("Unable to open file for writing");

    file.write_all(
        quote! {
            mod __diesel_infer_schema_articles {
                infer_table_from_schema!(#db_path, "articles");
            }
            pub use self::__diesel_infer_schema_articles::*;

            mod __diesel_infer_schema_article_revisions {
                infer_table_from_schema!(#db_path, "article_revisions");
            }
            pub use self::__diesel_infer_schema_article_revisions::*;
        }
        .to_string()
        .as_bytes(),
    )
    .expect("Unable to write to file");

    for entry in WalkDir::new("migrations")
        .into_iter()
        .filter_map(|e| e.ok())
    {
        println!("cargo:rerun-if-changed={}", entry.path().display());
    }

    // For build_config.rs
    for env_var in &["CONTINUOUS_INTEGRATION", "TRAVIS_BRANCH", "TRAVIS_COMMIT"] {
        println!("cargo:rerun-if-env-changed={}", env_var);
    }
}