storage: doc fixes (#228)

* database: doc fixes

* blockchain: doc fixes

* database: fix doc test

* database: readme fixes

* blockchain: ops fix

* blockchain: readme fix

storage/blockchain/README.md

@@ -5,6 +5,10 @@ This documentation is mostly for practical usage of `cuprate_blockchain`.
 For a high-level overview, see the database section in
 [Cuprate's architecture book](https://architecture.cuprate.org).
 
+If you're looking for a database crate, consider using the lower-level
+[`cuprate-database`](https://doc.cuprate.org/cuprate_database)
+crate that this crate is built on-top of.
+
 # Purpose
 This crate does 3 things:
 1. Uses [`cuprate_database`] as a base database layer
@@ -47,11 +51,11 @@ there are some things that must be kept in mind when doing so.
 Failing to uphold these invariants may cause panics.
 
 1. `LMDB` requires the user to resize the memory map resizing (see [`cuprate_database::RuntimeError::ResizeNeeded`]
-1. `LMDB` has a maximum reader transaction count, currently it is set to `128`
+1. `LMDB` has a maximum reader transaction count, currently, [it is set to `126`](https://github.com/LMDB/lmdb/blob/b8e54b4c31378932b69f1298972de54a565185b1/libraries/liblmdb/mdb.c#L794-L799)
 1. `LMDB` has [maximum key/value byte size](http://www.lmdb.tech/doc/group__internal.html#gac929399f5d93cef85f874b9e9b1d09e0) which must not be exceeded
 
 # Examples
-The below is an example of using `cuprate_blockchain`
+The below is an example of using `cuprate_blockchain`'s
 lowest API, i.e. using a mix of this crate and `cuprate_database`'s traits directly -
 **this is NOT recommended.**
 

storage/blockchain/src/config/reader_threads.rs

@@ -20,12 +20,11 @@ use serde::{Deserialize, Serialize};
 /// This controls how many reader thread `service`'s
 /// thread-pool will spawn to receive and send requests/responses.
 ///
-/// It does nothing outside of `service`.
+/// # Invariant
-///
-/// It will always be at least 1, up until the amount of threads on the machine.
-///
 /// The main function used to extract an actual
 /// usable thread count out of this is [`ReaderThreads::as_threads`].
+///
+/// This will always return at least 1, up until the amount of threads on the machine.
 #[derive(Copy, Clone, Debug, Default, PartialEq, PartialOrd)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub enum ReaderThreads {
@@ -97,30 +96,30 @@ impl ReaderThreads {
     ///
     /// # Example
     /// ```rust
-    /// use cuprate_blockchain::config::ReaderThreads as Rt;
+    /// use cuprate_blockchain::config::ReaderThreads as R;
     ///
     /// let total_threads: std::num::NonZeroUsize =
     ///     cuprate_helper::thread::threads();
     ///
-    /// assert_eq!(Rt::OnePerThread.as_threads(), total_threads);
+    /// assert_eq!(R::OnePerThread.as_threads(), total_threads);
     ///
-    /// assert_eq!(Rt::One.as_threads().get(), 1);
+    /// assert_eq!(R::One.as_threads().get(), 1);
     ///
-    /// assert_eq!(Rt::Number(0).as_threads(), total_threads);
+    /// assert_eq!(R::Number(0).as_threads(), total_threads);
-    /// assert_eq!(Rt::Number(1).as_threads().get(), 1);
+    /// assert_eq!(R::Number(1).as_threads().get(), 1);
-    /// assert_eq!(Rt::Number(usize::MAX).as_threads(), total_threads);
+    /// assert_eq!(R::Number(usize::MAX).as_threads(), total_threads);
     ///
-    /// assert_eq!(Rt::Percent(0.01).as_threads().get(), 1);
+    /// assert_eq!(R::Percent(0.01).as_threads().get(), 1);
-    /// assert_eq!(Rt::Percent(0.0).as_threads(), total_threads);
+    /// assert_eq!(R::Percent(0.0).as_threads(), total_threads);
-    /// assert_eq!(Rt::Percent(1.0).as_threads(), total_threads);
+    /// assert_eq!(R::Percent(1.0).as_threads(), total_threads);
-    /// assert_eq!(Rt::Percent(f32::NAN).as_threads(), total_threads);
+    /// assert_eq!(R::Percent(f32::NAN).as_threads(), total_threads);
-    /// assert_eq!(Rt::Percent(f32::INFINITY).as_threads(), total_threads);
+    /// assert_eq!(R::Percent(f32::INFINITY).as_threads(), total_threads);
-    /// assert_eq!(Rt::Percent(f32::NEG_INFINITY).as_threads(), total_threads);
+    /// assert_eq!(R::Percent(f32::NEG_INFINITY).as_threads(), total_threads);
     ///
     /// // Percentage only works on more than 1 thread.
     /// if total_threads.get() > 1 {
     ///     assert_eq!(
-    ///         Rt::Percent(0.5).as_threads().get(),
+    ///         R::Percent(0.5).as_threads().get(),
     ///         (total_threads.get() as f32 / 2.0) as usize,
     ///     );
     /// }

storage/blockchain/src/free.rs

@@ -6,7 +6,7 @@ use cuprate_database::{ConcreteEnv, Env, EnvInner, InitError, RuntimeError, TxRw
 use crate::{config::Config, tables::OpenTables};
 
 //---------------------------------------------------------------------------------------------------- Free functions
-/// Open the blockchain database, using the passed [`Config`].
+/// Open the blockchain database using the passed [`Config`].
 ///
 /// This calls [`cuprate_database::Env::open`] and prepares the
 /// database to be ready for blockchain-related usage, e.g.

storage/blockchain/src/ops/block.rs

@@ -1,4 +1,4 @@
-//! Blocks functions.
+//! Block functions.
 
 //---------------------------------------------------------------------------------------------------- Import
 use bytemuck::TransparentWrapper;

storage/blockchain/src/ops/mod.rs

@@ -5,14 +5,14 @@
 //! database operations.
 //!
 //! # `impl Table`
-//! `ops/` functions take [`Tables`](crate::tables::Tables) and
+//! Functions in this module take [`Tables`](crate::tables::Tables) and
 //! [`TablesMut`](crate::tables::TablesMut) directly - these are
 //! _already opened_ database tables.
 //!
-//! As such, the function puts the responsibility
+//! As such, the responsibility of
-//! of transactions, tables, etc on the caller.
+//! transactions, tables, etc, are on the caller.
 //!
-//! This does mean these functions are mostly as lean
+//! Notably, this means that these functions are as lean
 //! as possible, so calling them in a loop should be okay.
 //!
 //! # Atomicity

storage/database/README.md

@@ -6,10 +6,10 @@ For a high-level overview, see the database section in
 [Cuprate's architecture book](https://architecture.cuprate.org).
 
 If you need blockchain specific capabilities, consider using the higher-level
-`cuprate-blockchain` crate which builds upon this one.
+[`cuprate-blockchain`](https://doc.cuprate.org/cuprate_blockchain) crate which builds upon this one.
 
 # Purpose
-This crate abstracts various database backends with traits. The databases are:
+This crate abstracts various database backends with traits.
 
 All backends have the following attributes:
 - [Embedded](https://en.wikipedia.org/wiki/Embedded_database)
@@ -19,6 +19,10 @@ All backends have the following attributes:
 - Are table oriented (`"table_name" -> (key, value)`)
 - Allows concurrent readers
 
+The currently implemented backends are:
+- [`heed`](https://github.com/meilisearch/heed) (LMDB)
+- [`redb`](https://github.com/cberner/redb)
+
 # Terminology
 To be more clear on some terms used in this crate:
 
@@ -26,17 +30,17 @@ To be more clear on some terms used in this crate:
 |------------------|--------------------------------------|
 | `Env`            | The 1 database environment, the "whole" thing
 | `DatabaseR{o,w}` | A _actively open_ readable/writable `key/value` store
-| `Table`          | Solely the metadata of a `cuprate_database` (the `key` and `value` types, and the name)
+| `Table`          | Solely the metadata of a `Database` (the `key` and `value` types, and the name)
 | `TxR{o,w}`       | A read/write transaction
-| `Storable`       | A data that type can be stored in the database
+| `Storable`       | A data type that can be stored in the database
 
-The dataflow is `Env` -> `Tx` -> `cuprate_database`
+The flow is `Env` -> `Tx` -> `Database`
 
 Which reads as:
 1. You have a database `Environment`
 1. You open up a `Transaction`
-1. You open a particular `Table` from that `Environment`, getting a `cuprate_database`
+1. You open a particular `Table` from that `Environment`, getting a `Database`
-1. You can now read/write data from/to that `cuprate_database`
+1. You can now read/write data from/to that `Database`
 
 # Concrete types
 You should _not_ rely on the concrete type of any abstracted backend.

storage/database/src/config/config.rs

@@ -160,7 +160,7 @@ pub struct Config {
     /// Set the number of slots in the reader table.
     ///
     /// This is only used in LMDB, see
-    /// <https://github.com/LMDB/lmdb/blob/b8e54b4c31378932b69f1298972de54a565185b1/libraries/liblmdb/mdb.c#L794-L799>.
+    /// [here](https://github.com/LMDB/lmdb/blob/b8e54b4c31378932b69f1298972de54a565185b1/libraries/liblmdb/mdb.c#L794-L799).
     ///
     /// By default, this value is [`READER_THREADS_DEFAULT`].
     pub reader_threads: NonZeroUsize,

storage/database/src/config/sync_mode.rs

@@ -127,8 +127,8 @@ pub enum SyncMode {
     /// In the case of a system crash, the database
     /// may become corrupted when using this option.
     ///
-    /// [^1]:
+    ///
-    /// Semantically, this variant would actually map to
+    /// [^1]: Semantically, this variant would actually map to
     /// [`redb::Durability::None`](https://docs.rs/redb/1.5.0/redb/enum.Durability.html#variant.None),
     /// however due to [`#149`](https://github.com/Cuprate/cuprate/issues/149),
     /// this is not possible. As such, when using the `redb` backend,

storage/database/src/env.rs

@@ -24,15 +24,14 @@ use crate::{
 ///
 /// # Lifetimes
 /// The lifetimes associated with `Env` have a sequential flow:
-/// 1. `ConcreteEnv`
+/// ```text
-/// 2. `'env`
+/// Env -> Tx -> Database
-/// 3. `'tx`
+/// ```
-/// 4. `'db`
 ///
 /// As in:
 /// - open database tables only live as long as...
 /// - transactions which only live as long as the...
-/// - environment ([`EnvInner`])
+/// - database environment
 pub trait Env: Sized {
     //------------------------------------------------ Constants
     /// Does the database backend need to be manually
@@ -202,18 +201,19 @@ Subsequent table opens will follow the flags/ordering, but only if
 /// Note that when opening tables with [`EnvInner::open_db_ro`],
 /// they must be created first or else it will return error.
 ///
-/// Note that when opening tables with [`EnvInner::open_db_ro`],
-/// they must be created first or else it will return error.
-///
 /// See [`EnvInner::create_db`] for creating tables.
 ///
 /// # Invariant
 #[doc = doc_heed_create_db_invariant!()]
 pub trait EnvInner<'env> {
     /// The read-only transaction type of the backend.
-    type Ro<'a>: TxRo<'a>;
+    ///
+    /// `'tx` is the lifetime of the transaction itself.
+    type Ro<'tx>: TxRo<'tx>;
     /// The read-write transaction type of the backend.
-    type Rw<'a>: TxRw<'a>;
+    ///
+    /// `'tx` is the lifetime of the transaction itself.
+    type Rw<'tx>: TxRw<'tx>;
 
     /// Create a read-only transaction.
     ///
@@ -235,11 +235,37 @@ pub trait EnvInner<'env> {
     /// This will open the database [`Table`]
     /// passed as a generic to this function.
     ///
-    /// ```rust,ignore
+    /// ```rust
-    /// let db = env.open_db_ro::<Table>(&tx_ro);
+    /// # use cuprate_database::{
-    /// //  ^                     ^
+    /// #     ConcreteEnv,
-    /// // database table       table metadata
+    /// #     config::ConfigBuilder,
-    /// //                      (name, key/value type)
+    /// #     Env, EnvInner,
+    /// #     DatabaseRo, DatabaseRw, TxRo, TxRw,
+    /// # };
+    /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
+    /// # let tmp_dir = tempfile::tempdir()?;
+    /// # let db_dir = tmp_dir.path().to_owned();
+    /// # let config = ConfigBuilder::new(db_dir.into()).build();
+    /// # let env = ConcreteEnv::open(config)?;
+    /// #
+    /// # struct Table;
+    /// # impl cuprate_database::Table for Table {
+    /// #     const NAME: &'static str = "table";
+    /// #     type Key = u8;
+    /// #     type Value = u64;
+    /// # }
+    /// #
+    /// # let env_inner = env.env_inner();
+    /// # let tx_rw = env_inner.tx_rw()?;
+    /// # env_inner.create_db::<Table>(&tx_rw)?;
+    /// # TxRw::commit(tx_rw);
+    /// #
+    /// # let tx_ro = env_inner.tx_ro()?;
+    /// let db = env_inner.open_db_ro::<Table>(&tx_ro);
+    /// //  ^                           ^
+    /// // database table             table metadata
+    /// //                            (name, key/value type)
+    /// # Ok(()) }
     /// ```
     ///
     /// # Errors

storage/database/src/error.rs

@@ -59,18 +59,16 @@ pub enum InitError {
 }
 
 //---------------------------------------------------------------------------------------------------- RuntimeError
-/// Errors that occur _after_ successful ([`Env::open`](crate::env::Env::open)).
+/// Errors that occur _after_ successful [`Env::open`](crate::env::Env::open).
 ///
 /// There are no errors for:
 /// 1. Missing tables
 /// 2. (De)serialization
-/// 3. Shutdown errors
 ///
 /// as `cuprate_database` upholds the invariant that:
 ///
 /// 1. All tables exist
 /// 2. (De)serialization never fails
-/// 3. The database (thread-pool) only shuts down when all channels are dropped
 #[derive(thiserror::Error, Debug)]
 pub enum RuntimeError {
     /// The given key already existed in the database.

storage/database/src/storable.rs

@@ -129,7 +129,7 @@ where
 ///
 /// Slice types are owned both:
 /// - when returned from the database
-/// - in `put()`
+/// - in [`crate::DatabaseRw::put()`]
 ///
 /// This is needed as `impl Storable for Vec<T>` runs into impl conflicts.
 ///

storage/database/src/table.rs

@@ -8,6 +8,8 @@ use crate::{key::Key, storable::Storable};
 /// Database table metadata.
 ///
 /// Purely compile time information for database tables.
+///
+/// See [`crate::define_tables`] for bulk table generation.
 pub trait Table: 'static {
     /// Name of the database table.
     const NAME: &'static str;

storage/database/src/tables.rs

@@ -349,11 +349,18 @@ macro_rules! define_tables {
         /// Note that this is already implemented on [`cuprate_database::EnvInner`], thus:
         /// - You don't need to implement this
         /// - It can be called using `env_inner.open_tables()` notation
+        ///
+        /// # Creation before opening
+        /// As [`cuprate_database::EnvInner`] documentation states,
+        /// tables must be created before they are opened.
+        ///
+        /// I.e. [`OpenTables::create_tables`] must be called before
+        /// [`OpenTables::open_tables`] or else panics may occur.
         pub trait OpenTables<'env> {
             /// The read-only transaction type of the backend.
-            type Ro<'a>;
+            type Ro<'tx>;
             /// The read-write transaction type of the backend.
-            type Rw<'a>;
+            type Rw<'tx>;
 
             /// Open all tables in read/iter mode.
             ///
@@ -362,11 +369,6 @@ macro_rules! define_tables {
             ///
             /// # Errors
             /// This will only return [`cuprate_database::RuntimeError::Io`] if it errors.
-            ///
-            /// # Invariant
-            /// All tables should be created with a crate-specific open function.
-            ///
-            /// TODO: explain why
             fn open_tables(&self, tx_ro: &Self::Ro<'_>) -> Result<impl TablesIter, $crate::RuntimeError>;
 
             /// Open all tables in read-write mode.
@@ -391,8 +393,8 @@ macro_rules! define_tables {
         where
             Ei: $crate::EnvInner<'env>,
         {
-            type Ro<'a> = <Ei as $crate::EnvInner<'env>>::Ro<'a>;
+            type Ro<'tx> = <Ei as $crate::EnvInner<'env>>::Ro<'tx>;
-            type Rw<'a> = <Ei as $crate::EnvInner<'env>>::Rw<'a>;
+            type Rw<'tx> = <Ei as $crate::EnvInner<'env>>::Rw<'tx>;
 
             fn open_tables(&self, tx_ro: &Self::Ro<'_>) -> Result<impl TablesIter, $crate::RuntimeError> {
                 Ok(($(

storage/database/src/transaction.rs

@@ -11,7 +11,7 @@ use crate::error::RuntimeError;
 /// # Commit
 /// It's recommended but may not be necessary to call [`TxRo::commit`] in certain cases:
 /// - <https://docs.rs/heed/0.20.0-alpha.9/heed/struct.RoTxn.html#method.commit>
-pub trait TxRo<'env> {
+pub trait TxRo<'tx> {
     /// Commit the read-only transaction.
     ///
     /// # Errors
@@ -23,7 +23,7 @@ pub trait TxRo<'env> {
 /// Read/write database transaction.
 ///
 /// Returned from [`EnvInner::tx_rw`](crate::EnvInner::tx_rw).
-pub trait TxRw<'env> {
+pub trait TxRw<'tx> {
     /// Commit the read/write transaction.
     ///
     /// Note that this doesn't necessarily sync the database caches to disk.