1 files changed, 197 insertions, 0 deletions
diff --git a/development/libs/barrel/src/integrations/diesel.rs b/development/libs/barrel/src/integrations/diesel.rs
new file mode 100644
index 000000000000..f376c211fe7b
--- /dev/null
+++ b/development/libs/barrel/src/integrations/diesel.rs
@@ -0,0 +1,197 @@
+//!
+
+// This integration relies on _knowing_ which backend is being used at compile-time
+// This is a poor woman's XOR - if you know how to make it more pretty, PRs welcome <3
+#[cfg(any(
+    all(feature = "pg", feature = "mysql"),
+    all(feature = "pg", feature = "sqlite3"),
+    all(feature = "mysql", feature = "sqlite3")
+))]
+compile_error!("`barrel` can only integrate with `diesel` if you select one (1) backend!");
+
+use diesel_rs::connection::SimpleConnection;
+use diesel_rs::migration::{Migration, RunMigrationsError};
+use std::fs::{self, File};
+use std::io::prelude::*;
+use std::path::{Path, PathBuf};
+use std::process::Command;
+
+/// Represents a migration run inside Diesel
+///
+/// 1. Path
+/// 2. Version
+/// 3. Up
+/// 4. Down
+pub struct BarrelMigration(PathBuf, String, String, String);
+
+impl Migration for BarrelMigration {
+    fn file_path(&self) -> Option<&Path> {
+        Some(self.0.as_path())
+    }
+
+    fn version(&self) -> &str {
+        &self.1
+    }
+
+    fn run(&self, conn: &SimpleConnection) -> Result<(), RunMigrationsError> {
+        conn.batch_execute(&self.2)?;
+        Ok(())
+    }
+
+    fn revert(&self, conn: &SimpleConnection) -> Result<(), RunMigrationsError> {
+        conn.batch_execute(&self.3)?;
+        Ok(())
+    }
+}
+
+/// Generate migration files using the barrel schema builder
+pub fn generate_initial(path: &PathBuf) {
+    generate_initial_with_content(
+        path,
+        &"fn up(migr: &mut Migration) {} \n\n".to_string(),
+        &"fn down(migr: &mut Migration) {} \n".to_string(),
+    )
+}
+
+/// Generate migration files using the barrel schema builder with initial content
+pub fn generate_initial_with_content(path: &PathBuf, up_content: &String, down_content: &String) {
+    let migr_path = path.join("mod.rs");
+    println!("Creating {}", migr_path.display());
+
+    let mut barrel_migr = fs::File::create(migr_path).unwrap();
+    barrel_migr.write(b"/// Handle up migrations \n").unwrap();
+    barrel_migr.write(up_content.as_bytes()).unwrap();
+
+    barrel_migr.write(b"/// Handle down migrations \n").unwrap();
+    barrel_migr.write(down_content.as_bytes()).unwrap();
+}
+
+/// Generate a Migration from the provided path
+pub fn migration_from(path: &Path) -> Option<Box<Migration>> {
+    match path.join("mod.rs").exists() {
+        true => Some(run_barrel_migration_wrapper(&path.join("mod.rs"))),
+        false => None,
+    }
+}
+
+fn version_from_path(path: &Path) -> Result<String, ()> {
+    path.parent()
+        .unwrap_or_else(|| {
+            panic!(
+                "Migration doesn't appear to be in a directory: `{:?}`",
+                path
+            )
+        })
+        .file_name()
+        .unwrap_or_else(|| panic!("Can't get file name from path `{:?}`", path))
+        .to_string_lossy()
+        .split('_')
+        .nth(0)
+        .map(|s| Ok(s.replace('-', "")))
+        .unwrap_or_else(|| Err(()))
+}
+
+fn run_barrel_migration_wrapper(path: &Path) -> Box<Migration> {
+    let (up, down) = run_barrel_migration(&path);
+    let version = version_from_path(path).unwrap();
+    let migration_path = match path.parent() {
+        Some(parent_path) => parent_path.to_path_buf(),
+        None => path.to_path_buf(),
+    };
+    Box::new(BarrelMigration(migration_path, version, up, down))
+}
+
+fn run_barrel_migration(migration: &Path) -> (String, String) {
+    /* Create a tmp dir with src/ child */
+    use tempfile::Builder;
+
+    let dir = Builder::new().prefix("barrel").tempdir().unwrap();
+    fs::create_dir_all(&dir.path().join("src")).unwrap();
+
+    let (feat, ident) = get_backend_pair();
+
+    let toml = format!(
+        "# This file is auto generated by barrel
+[package]
+name = \"tmp-generator\"
+description = \"Doing nasty things with cargo\"
+version = \"0.0.0\"
+authors = [\"Katharina Fey <kookie@spacekookie.de>\"]
+# TODO: Use same `barrel` dependency as crate
+[dependencies]
+barrel = {{ version = \"*\", features = [ {:?} ] }}",
+        feat
+    );
+
+    /* Add a Cargo.toml file */
+    let ct = dir.path().join("Cargo.toml");
+    let mut cargo_toml = File::create(&ct).unwrap();
+    cargo_toml.write_all(toml.as_bytes()).unwrap();
+
+    /* Generate main.rs based on user migration */
+    let main_file_path = &dir.path().join("src").join("main.rs");
+    let mut main_file = File::create(&main_file_path).unwrap();
+
+    let user_migration = migration.as_os_str().to_os_string().into_string().unwrap();
+    main_file
+        .write_all(
+            format!(
+                "//! This file is auto generated by barrel
+extern crate barrel;
+use barrel::*;
+
+use barrel::backend::{ident};
+
+include!(\"{}\");
+
+fn main() {{
+    let mut m_up = Migration::new();
+    up(&mut m_up);
+    println!(\"{{}}\", m_up.make::<{ident}>());
+
+    let mut m_down = Migration::new();
+    down(&mut m_down);
+    println!(\"{{}}\", m_down.make::<{ident}>());
+}}
+",
+                user_migration,
+                ident = ident
+            )
+            .as_bytes(),
+        )
+        .unwrap();
+
+    let output = if cfg!(target_os = "windows") {
+        Command::new("cargo")
+            .current_dir(dir.path())
+            .arg("run")
+            .output()
+            .expect("failed to execute cargo!")
+    } else {
+        Command::new("sh")
+            .current_dir(dir.path())
+            .arg("-c")
+            .arg("cargo run")
+            .output()
+            .expect("failed to execute cargo!")
+    };
+
+    let output = String::from_utf8_lossy(&output.stdout);
+    let vec: Vec<&str> = output.split("\n").collect();
+    let up = String::from(vec[0]);
+    let down = String::from(vec[1]);
+
+    (up, down)
+}
+
+/// Uses the fact that barrel with diesel support is only compiled with _one_ feature
+///
+/// The first string is the feature-name, the other the struct ident
+fn get_backend_pair() -> (&'static str, &'static str) {
+    #[cfg(feature = "pg")]
+    return ("pg", "Pg");
+    #[cfg(feature = "mysql")]
+    return ("mysql", "Mysql");
+    #[cfg(feature = "sqlite3")]
+    return ("sqlite3", "Sqlite");
+}