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/* 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/. */ #![deny( missing_docs, non_camel_case_types, non_snake_case, path_statements, trivial_casts, trivial_numeric_casts, unsafe_code, unstable_features, unused_allocation, unused_import_braces, unused_imports, unused_must_use, unused_mut, while_true, )] //! # Rustbreak //! //! Rustbreak was a [Daybreak][daybreak] inspired single file Database. //! It has now since evolved into something else. Please check v1 for a more similar version. //! //! You will find an overview here in the docs, but to give you a more complete tale of how this is //! used please check the [examples][examples]. //! //! At its core, Rustbreak is an attempt at making a configurable general-purpose store Database. //! It features the possibility of: //! //! - Choosing what kind of Data is stored in it //! - Which kind of Serialization is used for persistence //! - Which kind of persistence is used //! //! This means you can take any struct you can serialize and deserialize and stick it into this //! Database. It is then encoded with Ron, Yaml, JSON, Bincode, anything really that uses Serde //! operations! //! //! There are two helper type aliases `MemoryDatabase` and `FileDatabase`, each backed by their //! respective backend. //! //! The `MemoryBackend` saves its data into a `Vec<u8>`, which is not that useful on its own, but //! is needed for compatibility with the rest of the Library. //! //! The `FileDatabase` is a classical file based database. You give it a path or a file, and it //! will use it as its storage. You still get to pick what encoding it uses. //! //! Using the `with_deser` and `with_backend` one can switch between the representations one needs. //! Even at runtime! However this is only useful in a few scenarios. //! //! If you have any questions feel free to ask at the main [repo][repo]. //! //! ## Quickstart //! //! Add this to your `Cargo.toml`: //! //! ```toml //! [dependencies.rustbreak] //! version = "2" //! features = ["ron_enc"] # You can also use "yaml_enc" or "bin_enc" //! # Check the documentation to add your own! //! ``` //! //! ```rust //! # extern crate failure; //! # extern crate rustbreak; //! # use std::collections::HashMap; //! use rustbreak::{MemoryDatabase, deser::Ron}; //! //! # fn main() { //! # let func = || -> Result<(), failure::Error> { //! let db = MemoryDatabase::<HashMap<u32, String>, Ron>::memory(HashMap::new())?; //! //! println!("Writing to Database"); //! db.write(|db| { //! db.insert(0, String::from("world")); //! db.insert(1, String::from("bar")); //! }); //! //! db.read(|db| { //! // db.insert("foo".into(), String::from("bar")); //! // The above line will not compile since we are only reading //! println!("Hello: {:?}", db.get(&0)); //! })?; //! # return Ok(()); }; //! # func().unwrap(); //! # } //! ``` //! //! Or alternatively: //! ```rust //! # extern crate failure; //! # extern crate rustbreak; //! # use std::collections::HashMap; //! use rustbreak::{MemoryDatabase, deser::Ron}; //! //! # fn main() { //! # let func = || -> Result<(), failure::Error> { //! let db = MemoryDatabase::<HashMap<u32, String>, Ron>::memory(HashMap::new())?; //! //! println!("Writing to Database"); //! { //! let mut data = db.borrow_data_mut()?; //! data.insert(0, String::from("world")); //! data.insert(1, String::from("bar")); //! } //! //! let data = db.borrow_data()?; //! println!("Hello: {:?}", data.get(&0)); //! # return Ok(()); }; //! # func().unwrap(); //! # } //! ``` //! //! ## Error Handling //! //! Handling errors in Rustbreak is straightforward. Every `Result` has as its fail case as //! `error::RustbreakError`. This means that you can now either continue bubbling up said error //! case, or handle it yourself. //! //! You can simply call its `.kind()` method, giving you all the information you need to continue. //! //! ```rust //! use rustbreak::{ //! MemoryDatabase, //! deser::Ron, //! error::{ //! RustbreakError, //! } //! }; //! let db = match MemoryDatabase::<usize, Ron>::memory(0) { //! Ok(db) => db, //! Err(e) => { //! // Do something with `e` here //! ::std::process::exit(1); //! } //! }; //! ``` //! //! ## Panics //! //! This Database implementation uses `RwLock` and `Mutex` under the hood. If either the closures //! given to `Database::write` or any of the Backend implementation methods panic the respective //! objects are then poisoned. This means that you *cannot panic* under any circumstances in your //! closures or custom backends. //! //! Currently there is no way to recover from a poisoned `Database` other than re-creating it. //! //! ## Examples //! //! There are several more or less in-depth example programs you can check out! //! Check them out here: [Examples][examples] //! //! - `config.rs` shows you how a possible configuration file could be managed with rustbreak //! - `full.rs` shows you how the database can be used as a hashmap store //! - `switching.rs` show you how you can easily swap out different parts of the Database //! *Note*: To run this example you need to enable the feature `yaml` like so: //! `cargo run --example switching --features yaml` //! - `server/` is a fully fledged example app written with the Rocket framework to make a form of //! micro-blogging website. You will need rust nightly to start it. //! //! ## Features //! //! Rustbreak comes with following optional features: //! //! - `ron_enc` which enables the [Ron][ron] de/serialization //! - `yaml_enc` which enables the Yaml de/serialization //! - `bin_enc` which enables the Bincode de/serialization //! - 'mmap' whhich enables memory map backend. //! //! [Enable them in your `Cargo.toml` file to use them.][features] You can safely have them all //! turned on per-default. //! //! //! [repo]: https://github.com/TheNeikos/rustbreak //! [daybreak]: https://propublica.github.io/daybreak //! [examples]: https://github.com/TheNeikos/rustbreak/tree/master/examples //! [ron]: https://github.com/ron-rs/ron //! [failure]: https://boats.gitlab.io/failure/intro.html //! [features]: https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#choosing-features extern crate serde; #[macro_use] extern crate failure; #[cfg(feature = "ron_enc")] extern crate ron; #[cfg(feature = "yaml_enc")] extern crate serde_yaml; #[cfg(feature = "bin_enc")] extern crate bincode; #[cfg(feature = "bin_enc")] extern crate base64; #[cfg(feature = "mmap")] extern crate memmap; #[cfg(test)] extern crate tempfile; /// The rustbreak errors that can be returned pub mod error; pub mod backend; /// Different serialization and deserialization methods one can use pub mod deser; /// The `DeSerializer` trait used by serialization structs pub use deser::DeSerializer; /// The general error used by the Rustbreak Module pub use error::RustbreakError; use std::sync::{Mutex, RwLock, RwLockReadGuard, RwLockWriteGuard}; use std::fmt::Debug; use serde::Serialize; use serde::de::DeserializeOwned; use failure::ResultExt; use backend::{Backend, MemoryBackend, FileBackend}; #[cfg(feature = "mmap")] use backend::MmapStorage; /// The Central Database to RustBreak /// /// It has 3 Type Generics: /// /// - Data: Is the Data, you must specify this /// - Back: The storage backend. /// - DeSer: The Serializer/Deserializer or short DeSer. Check the `deser` module for other /// strategies. /// /// # Panics /// /// If the backend or the de/serialization panics, the database is poisoned. This means that any /// subsequent writes/reads will fail with an `error::RustbreakErrorKind::PoisonError`. /// You can only recover from this by re-creating the Database Object. #[derive(Debug)] pub struct Database<Data, Back, DeSer> { data: RwLock<Data>, backend: Mutex<Back>, deser: DeSer } impl<Data, Back, DeSer> Database<Data, Back, DeSer> where Data: Serialize + DeserializeOwned + Debug + Clone + Send, Back: Backend + Debug, DeSer: DeSerializer<Data> + Debug + Send + Sync + Clone { /// Write lock the database and get write access to the `Data` container /// /// This gives you an exclusive lock on the memory object. Trying to open the database in /// writing will block if it is currently being written to. /// /// # Panics /// /// If you panic in the closure, the database is poisoned. This means that any /// subsequent writes/reads will fail with an `std::sync::PoisonError`. /// You can only recover from this by re-creating the Database Object. /// /// If you do not have full control over the code being written, and cannot incur the cost of /// having a single operation panicking then use `Database::write_safe`. /// /// # Examples /// /// ```rust /// # #[macro_use] extern crate serde_derive; /// # extern crate rustbreak; /// # extern crate serde; /// # extern crate tempfile; /// # extern crate failure; /// use rustbreak::{FileDatabase, deser::Ron}; /// /// #[derive(Debug, Serialize, Deserialize, Clone)] /// struct Data { /// level: u32, /// } /// /// # fn main() { /// # let func = || -> Result<(), failure::Error> { /// # let file = tempfile::tempfile()?; /// let db = FileDatabase::<Data, Ron>::from_file(file, Data { level: 0 })?; /// /// db.write(|db| { /// db.level = 42; /// })?; /// /// // You can also return from a `.read()`. But don't forget that you cannot return references /// // into the structure /// let value = db.read(|db| db.level)?; /// assert_eq!(42, value); /// # return Ok(()); /// # }; /// # func().unwrap(); /// # } /// ``` pub fn write<T, R>(&self, task: T) -> error::Result<R> where T: FnOnce(&mut Data) -> R { let mut lock = self.data.write().map_err(|_| error::RustbreakErrorKind::Poison)?; Ok(task(&mut lock)) } /// Write lock the database and get write access to the `Data` container in a safe way /// /// This gives you an exclusive lock on the memory object. Trying to open the database in /// writing will block if it is currently being written to. /// /// This differs to `Database::write` in that a clone of the internal data is made, which is /// then passed to the closure. Only if the closure doesn't panic is the internal model /// updated. /// /// Depending on the size of the database this can be very costly. This is a tradeoff to make /// for panic safety. /// /// You should read the documentation about this: /// [UnwindSafe](https://doc.rust-lang.org/std/panic/trait.UnwindSafe.html) /// /// # Panics /// /// When the closure panics, it is caught and a `error::RustbreakErrorKind::WritePanic` will be /// returned. /// /// # Examples /// /// ```rust /// # #[macro_use] extern crate serde_derive; /// # extern crate rustbreak; /// # extern crate serde; /// # extern crate tempfile; /// # extern crate failure; /// use rustbreak::{ /// FileDatabase, /// deser::Ron, /// error::{ /// RustbreakError, /// RustbreakErrorKind, /// } /// }; /// /// #[derive(Debug, Serialize, Deserialize, Clone)] /// struct Data { /// level: u32, /// } /// /// # fn main() { /// # let func = || -> Result<(), failure::Error> { /// # let file = tempfile::tempfile()?; /// let db = FileDatabase::<Data, Ron>::from_file(file, Data { level: 0 })?; /// /// let result = db.write_safe(|db| { /// db.level = 42; /// panic!("We panic inside the write code."); /// }).expect_err("This should have been caught"); /// /// match result.kind() { /// RustbreakErrorKind::WritePanic => { /// // We can now handle this, in this example we will just ignore it /// } /// e => { /// println!("{:#?}", e); /// // You should always have generic error catching here. /// // This future-proofs your code, and makes your code more robust. /// // In this example this is unreachable though, and to assert that we have this /// // macro here /// unreachable!(); /// } /// } /// /// // We read it back out again, it has not changed /// let value = db.read(|db| db.level)?; /// assert_eq!(0, value); /// # return Ok(()); /// # }; /// # func().unwrap(); /// # } /// ``` pub fn write_safe<T>(&self, task: T) -> error::Result<()> where T: FnOnce(&mut Data) + std::panic::UnwindSafe, { let mut lock = self.data.write().map_err(|_| error::RustbreakErrorKind::Poison)?; let mut data = lock.clone(); ::std::panic::catch_unwind(::std::panic::AssertUnwindSafe(|| { task(&mut data); })).map_err(|_| error::RustbreakErrorKind::WritePanic)?; *lock = data; Ok(()) } /// Read lock the database and get write access to the `Data` container /// /// This gives you a read-only lock on the database. You can have as many readers in parallel /// as you wish. /// /// # Errors /// /// May return: /// /// - `error::RustbreakErrorKind::Backend` /// /// # Panics /// /// If you panic in the closure, the database is poisoned. This means that any /// subsequent writes/reads will fail with an `error::RustbreakErrorKind::Poison`. /// You can only recover from this by re-creating the Database Object. pub fn read<T, R>(&self, task: T) -> error::Result<R> where T: FnOnce(&Data) -> R { let mut lock = self.data.read().map_err(|_| error::RustbreakErrorKind::Poison)?; Ok(task(&mut lock)) } /// Read lock the database and get access to the underlying struct /// /// This gives you access to the underlying struct, allowing for simple read /// only operations on it. /// /// # Examples /// /// ```rust /// # #[macro_use] extern crate serde_derive; /// # extern crate rustbreak; /// # extern crate serde; /// # extern crate tempfile; /// # extern crate failure; /// use rustbreak::{FileDatabase, deser::Ron}; /// /// #[derive(Debug, Serialize, Deserialize, Clone)] /// struct Data { /// level: u32, /// } /// /// # fn main() { /// # let func = || -> Result<(), failure::Error> { /// # let file = tempfile::tempfile()?; /// let db = FileDatabase::<Data, Ron>::from_file(file, Data { level: 0 })?; /// /// db.write(|db| { /// db.level = 42; /// })?; /// /// let data = db.borrow_data()?; /// /// assert_eq!(42, data.level); /// # return Ok(()); /// # }; /// # func().unwrap(); /// # } /// ``` pub fn borrow_data<'a>(&'a self) -> error::Result<RwLockReadGuard<'a, Data>> { self.data.read().map_err(|_| error::RustbreakErrorKind::Poison.into()) } /// Write lock the database and get access to the underlying struct /// /// This gives you access to the underlying struct, allowing you to modify it. /// /// # Panics /// /// If you panic while holding this reference, the database is poisoned. This means that any /// subsequent writes/reads will fail with an `std::sync::PoisonError`. /// You can only recover from this by re-creating the Database Object. /// /// If you do not have full control over the code being written, and cannot incur the cost of /// having a single operation panicking then use `Database::write_safe`. /// /// # Examples /// /// ```rust /// # #[macro_use] extern crate serde_derive; /// # extern crate rustbreak; /// # extern crate serde; /// # extern crate tempfile; /// # extern crate failure; /// use rustbreak::{FileDatabase, deser::Ron}; /// /// #[derive(Debug, Serialize, Deserialize, Clone)] /// struct Data { /// level: u32, /// } /// /// # fn main() { /// # let func = || -> Result<(), failure::Error> { /// # let file = tempfile::tempfile()?; /// let db = FileDatabase::<Data, Ron>::from_file(file, Data { level: 0 })?; /// /// { /// let mut data = db.borrow_data_mut()?; /// data.level = 42; /// } /// /// let data = db.borrow_data()?; /// /// assert_eq!(42, data.level); /// # return Ok(()); /// # }; /// # func().unwrap(); /// # } /// ``` pub fn borrow_data_mut<'a>(&'a self) -> error::Result<RwLockWriteGuard<'a, Data>> { self.data.write().map_err(|_| error::RustbreakErrorKind::Poison.into()) } fn inner_load(backend: &mut Back, deser: &DeSer) -> error::Result<Data> { let new_data = deser.deserialize( &backend.get_data().context(error::RustbreakErrorKind::Backend)?[..] ).context(error::RustbreakErrorKind::Deserialization)?; Ok(new_data) } /// Load the Data from the backend pub fn load(&self) -> error::Result<()> { let mut data = self.data.write().map_err(|_| error::RustbreakErrorKind::Poison)?; let mut backend = self.backend.lock().map_err(|_| error::RustbreakErrorKind::Poison)?; *data = Self::inner_load(&mut backend, &self.deser).context(error::RustbreakErrorKind::Backend)?; Ok(()) } /// Flush the data structure to the backend pub fn save(&self) -> error::Result<()> { let mut backend = self.backend.lock().map_err(|_| error::RustbreakErrorKind::Poison)?; let data = self.data.write().map_err(|_| error::RustbreakErrorKind::Poison)?; let ser = self.deser.serialize(&*data) .context(error::RustbreakErrorKind::Serialization)?; backend.put_data(&ser).context(error::RustbreakErrorKind::Backend)?; Ok(()) } /// Get a clone of the data as it is in memory right now /// /// To make sure you have the latest data, call this method with `load` true pub fn get_data(&self, load: bool) -> error::Result<Data> { let mut backend = self.backend.lock().map_err(|_| error::RustbreakErrorKind::Poison)?; let mut data = self.data.write().map_err(|_| error::RustbreakErrorKind::Poison)?; if load { *data = Self::inner_load(&mut backend, &self.deser).context(error::RustbreakErrorKind::Backend)?; drop(backend); } Ok(data.clone()) } /// Puts the data as is into memory /// /// To save the data afterwards, call with `save` true. pub fn put_data(&self, new_data: Data, save: bool) -> error::Result<()> { let mut backend = self.backend.lock().map_err(|_| error::RustbreakErrorKind::Poison)?; let mut data = self.data.write().map_err(|_| error::RustbreakErrorKind::Poison)?; if save { // TODO: Spin this into its own method let ser = self.deser.serialize(&*data) .context(error::RustbreakErrorKind::Serialization)?; backend.put_data(&ser).context(error::RustbreakErrorKind::Backend)?; drop(backend); } *data = new_data; Ok(()) } /// Create a database from its constituents pub fn from_parts(data: Data, backend: Back, deser: DeSer) -> Database<Data, Back, DeSer> { Database { data: RwLock::new(data), backend: Mutex::new(backend), deser: deser, } } /// Break a database into its individual parts pub fn into_inner(self) -> error::Result<(Data, Back, DeSer)> { Ok((self.data.into_inner().map_err(|_| error::RustbreakErrorKind::Poison)?, self.backend.into_inner().map_err(|_| error::RustbreakErrorKind::Poison)?, self.deser)) } /// Tries to clone the Data in the Database. /// /// This method returns a `MemoryDatabase` which has an empty vector as a /// backend initially. This means that the user is responsible for assigning a new backend /// if an alternative is wanted. /// /// # Examples /// /// ```rust /// # #[macro_use] extern crate serde_derive; /// # extern crate rustbreak; /// # extern crate serde; /// # extern crate tempfile; /// # extern crate failure; /// use rustbreak::{FileDatabase, deser::Ron}; /// /// #[derive(Debug, Serialize, Deserialize, Clone)] /// struct Data { /// level: u32, /// } /// /// # fn main() { /// # let func = || -> Result<(), failure::Error> { /// # let file = tempfile::tempfile()?; /// let db = FileDatabase::<Data, Ron>::from_file(file, Data { level: 0 })?; /// /// db.write(|db| { /// db.level = 42; /// })?; /// /// db.save()?; /// /// let other_db = db.try_clone()?; /// /// // You can also return from a `.read()`. But don't forget that you cannot return references /// // into the structure /// let value = other_db.read(|db| db.level)?; /// assert_eq!(42, value); /// # return Ok(()); /// # }; /// # func().unwrap(); /// # } /// ``` pub fn try_clone(&self) -> error::Result<MemoryDatabase<Data, DeSer>> { let lock = self.data.write().map_err(|_| error::RustbreakErrorKind::Poison)?; Ok(Database { data: RwLock::new(lock.clone()), backend: Mutex::new(MemoryBackend::new()), deser: self.deser.clone(), }) } } /// A database backed by a file pub type FileDatabase<D, DS> = Database<D, FileBackend, DS>; impl<Data, DeSer> Database<Data, FileBackend, DeSer> where Data: Serialize + DeserializeOwned + Debug + Clone + Send, DeSer: DeSerializer<Data> + Debug + Send + Sync + Clone { /// Create new FileDatabase from Path pub fn from_path<S>(path: S, data: Data) -> error::Result<FileDatabase<Data, DeSer>> where S: AsRef<std::path::Path> { let backend = FileBackend::open(path).context(error::RustbreakErrorKind::Backend)?; Ok(Database { data: RwLock::new(data), backend: Mutex::new(backend), deser: DeSer::default(), }) } /// Create new FileDatabase from a file pub fn from_file(file: ::std::fs::File, data: Data) -> error::Result<FileDatabase<Data, DeSer>> { let backend = FileBackend::from_file(file); Ok(Database { data: RwLock::new(data), backend: Mutex::new(backend), deser: DeSer::default(), }) } } /// A database backed by a `Vec<u8>` pub type MemoryDatabase<D, DS> = Database<D, MemoryBackend, DS>; impl<Data, DeSer> Database<Data, MemoryBackend, DeSer> where Data: Serialize + DeserializeOwned + Debug + Clone + Send, DeSer: DeSerializer<Data> + Debug + Send + Sync + Clone { /// Create new FileDatabase from Path pub fn memory(data: Data) -> error::Result<MemoryDatabase<Data, DeSer>> { let backend = MemoryBackend::new(); Ok(Database { data: RwLock::new(data), backend: Mutex::new(backend), deser: DeSer::default(), }) } } /// A database backed by anonymous memory map. #[cfg(feature = "mmap")] pub type MmapDatabase<D, DS> = Database<D, MmapStorage, DS>; #[cfg(feature = "mmap")] impl<Data, DeSer> Database<Data, MmapStorage, DeSer> where Data: Serialize + DeserializeOwned + Debug + Clone + Send, DeSer: DeSerializer<Data> + Debug + Send + Sync + Clone { /// Create new MmapDatabase. pub fn mmap(data: Data) -> error::Result<MmapDatabase<Data, DeSer>> { let backend = MmapStorage::new()?; Ok(Database { data: RwLock::new(data), backend: Mutex::new(backend), deser: DeSer::default(), }) } /// Create new MmapDatabase with specified initial size. pub fn mmap_with_size(data: Data, size: usize) -> error::Result<MmapDatabase<Data, DeSer>> { let backend = MmapStorage::with_size(size)?; Ok(Database { data: RwLock::new(data), backend: Mutex::new(backend), deser: DeSer::default(), }) } } impl<Data, Back, DeSer> Database<Data, Back, DeSer> { /// Exchanges the DeSerialization strategy with the new one pub fn with_deser<T>(self, deser: T) -> Database<Data, Back, T> { Database { backend: self.backend, data: self.data, deser: deser, } } } impl<Data, Back, DeSer> Database<Data, Back, DeSer> { /// Exchanges the Backend with the new one /// /// The new backend does not necessarily have the latest data saved to it, so a `.save` should /// be called to make sure that it is saved. pub fn with_backend<T>(self, backend: T) -> Database<Data, T, DeSer> { Database { backend: Mutex::new(backend), data: self.data, deser: self.deser, } } } impl<Data, Back, DeSer> Database<Data, Back, DeSer> where Data: Serialize + DeserializeOwned + Debug + Clone + Send, Back: Backend + Debug, DeSer: DeSerializer<Data> + Debug + Send + Sync + Clone { /// Converts from one data type to another /// /// This method is useful to migrate from one datatype to another pub fn convert_data<C, OutputData>(self, convert: C) -> error::Result<Database<OutputData, Back, DeSer>> where OutputData: Serialize + DeserializeOwned + Debug + Clone + Send, C: FnOnce(Data) -> OutputData, DeSer: DeSerializer<OutputData> + Debug + Send + Sync, { let (data, backend, deser) = self.into_inner()?; Ok(Database { data: RwLock::new(convert(data)), backend: Mutex::new(backend), deser: deser, }) } }