feat: add error and fs utils

migra/src/error.rs

@@ -0,0 +1,32 @@
+use std::fmt;
+use std::io;
+
+pub type MigraResult<T> = Result<T, Error>;
+
+#[derive(Debug)]
+pub enum Error {
+    Io(io::Error),
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Error::Io(ref error) => write!(fmt, "{}", error),
+        }
+    }
+}
+
+impl std::error::Error for Error {}
+
+impl PartialEq for Error {
+    fn eq(&self, other: &Self) -> bool {
+        std::mem::discriminant(self) == std::mem::discriminant(other)
+    }
+}
+
+impl From<io::Error> for Error {
+    #[inline]
+    fn from(err: io::Error) -> Error {
+        Error::Io(err)
+    }
+}

migra/src/fs.rs

@@ -0,0 +1,33 @@
+use crate::error::MigraResult;
+use crate::migration;
+use std::io;
+use std::path::Path;
+
+#[must_use]
+pub fn is_migration_dir(path: &Path) -> bool {
+    path.join("up.sql").exists() && path.join("down.sql").exists()
+}
+
+pub fn get_all_migrations(dir_path: &Path) -> MigraResult<migration::List> {
+    let mut entries = match dir_path.read_dir() {
+        Err(e) if e.kind() == io::ErrorKind::NotFound => vec![],
+        entries => entries?
+            .filter_map(|res| res.ok().map(|e| e.path()))
+            .filter(|path| is_migration_dir(&path))
+            .collect::<Vec<_>>(),
+    };
+
+    if entries.is_empty() {
+        return Ok(migration::List::new());
+    }
+
+    entries.sort();
+
+    let file_names = entries
+        .iter()
+        .filter_map(|path| path.file_name())
+        .filter_map(std::ffi::OsStr::to_str)
+        .collect::<Vec<_>>();
+
+    Ok(migration::List::from(file_names))
+}

migra/src/lib.rs

@@ -2,4 +2,36 @@
 #![deny(clippy::all, clippy::pedantic)]
 #![allow(clippy::missing_errors_doc)]
 
+mod error;
+pub mod fs;
 pub mod migration;
+
+pub use error::{Error, MigraResult as Result};
+
+/*
+
+# list
+
+fs::get_all_migrations()
+db::get_applied_migrations()
+utils::filter_pending_migrations(all_migrations, applied_migrations)
+show_migrations(applied_migrations)
+show_migrations(pending_migrations)
+
+
+# upgrade
+
+fs::get_all_migrations()
+db::get_applied_migrations()
+utils::filter_pending_migrations(all_migrations, applied_migrations)
+
+db::upgrade_migration()
+
+
+
+# downgrade
+
+
+
+
+*/