notesmachine/server/nm-store/src/store.rs

97 lines
3.9 KiB
Rust

// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
//! # Storage layer for Notesmachine
//!
//! This library implements the core functionality of Notesmachine and
//! describes that functionality to a storage layer. There's a bit of
//! intermingling in here which can't be helped, although it may make
//! sense in the future to separate the decomposition of the note
//! content into a higher layer.
//!
//! Notesmachine storage notes consist of two items: Zettle and Kasten.
//! This distinction is somewhat arbitrary, as structurally these two
//! items are stored in the same table.
//!
//! - Boxes have titles (and date metadata)
//! - Notes have content and a type (and date metadata)
//! - Notes are stored in boxes
//! - Notes are positioned with respect to other notes.
//! - There are two positions:
//! - Siblings, creating lists
//! - Children, creating trees like this one
//! - Notes may have references (pointers) to other boxes
//! - Notes may be moved around
//! - Notes may be deleted
//! - Boxes may be deleted
//! - When a box is renamed, every reference to that box is auto-edited to
//! reflect the change. If a box is renamed to match an existing box, the
//! notes in both boxes are merged.
//!
//! Note-to-note relationships form trees, and are kept in a SQL database of
//! (`parent_id`, `child_id`, `position`, `relationship_type`). The
//! `position` is a monotonic index on the parent (that is, every pair
//! (`parent_id`, `position`) must be unique). The `relationship_type` is
//! an enum and can specify that the relationship is *original*,
//! *embedding*, or *referencing*. An embedded or referenced note may be
//! read/write or read-only with respect to the original, but there is only
//! one original note at any time.
//!
//! Note-to-box relationships form a graph, and are kept in the SQL database
//! as a collection of *edges* from the note to the box (and naturally
//! vice-versa).
//!
//! - Decision: When an original note is deleted, do all references and
//! embeddings also get deleted, or is the oldest one elevated to be a new
//! "original"? Or is that something the user may choose?
//!
//! - Decision: Should the merging issue be handled at this layer, or would
//! it make sense to move this to a higher layer, and only provide the
//! hooks for it here?
//!
use crate::errors::NoteStoreError;
use crate::store_private::*;
use crate::structs::*;
use sqlx::sqlite::SqlitePool;
use std::cmp;
use std::collections::HashMap;
use std::sync::Arc;
/// A handle to our Sqlite database.
#[derive(Clone, Debug)]
pub struct NoteStore(Arc<SqlitePool>);
type NoteResult<T> = core::result::Result<T, NoteStoreError>;
impl NoteStore {
/// Initializes a new instance of the note store. Note that the
/// note store holds an Arc internally; this code is (I think)
/// safe to Send.
pub async fn new(url: &str) -> NoteResult<Self> {
let pool = SqlitePool::connect(url).await?;
Ok(NoteStore(Arc::new(pool)))
}
/// Erase all the data in the database and restore it
/// to its original empty form. Do not use unless you
/// really, really want that to happen.
pub async fn reset_database(&self) -> NoteResult<()> {
reset_database(&*self.0).await.map_err(NoteStoreError::DBError)
}
/// Fetch page by slug
///
/// Supports the use case of the user navigating to a known place
/// via a bookmark or other URL. Since the title isn't clear from
/// the slug, the slug is insufficient to generate a new page, so
/// this use case says that in the event of a failure to find the
/// requested page, return a basic NotFound.
pub async fn get_kasten_by_slug(&self, slug: &str) -> NoteResult<Vec<RawZettle>> {
let page = select_kasten_by_slug(&*self.0, slug).await?;
Ok(page)
}
}