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Rewrite delivery/processing code

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This commit is contained in:
Riley Apeldoorn 2024-05-05 16:18:23 +02:00
parent d1b08f1b07
commit 7641add472
8 changed files with 720 additions and 33 deletions
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51
Cargo.lock generated
View file

@ -518,6 +518,21 @@ dependencies = [
"percent-encoding",
]
[[package]]
name = "futures"
version = "0.3.30"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "645c6916888f6cb6350d2550b80fb63e734897a8498abe35cfb732b6487804b0"
dependencies = [
"futures-channel",
"futures-core",
"futures-executor",
"futures-io",
"futures-sink",
"futures-task",
"futures-util",
]
[[package]]
name = "futures-channel"
version = "0.3.30"
@ -525,6 +540,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "eac8f7d7865dcb88bd4373ab671c8cf4508703796caa2b1985a9ca867b3fcb78"
dependencies = [
"futures-core",
"futures-sink",
]
[[package]]
@ -533,6 +549,34 @@ version = "0.3.30"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "dfc6580bb841c5a68e9ef15c77ccc837b40a7504914d52e47b8b0e9bbda25a1d"
[[package]]
name = "futures-executor"
version = "0.3.30"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "a576fc72ae164fca6b9db127eaa9a9dda0d61316034f33a0a0d4eda41f02b01d"
dependencies = [
"futures-core",
"futures-task",
"futures-util",
]
[[package]]
name = "futures-io"
version = "0.3.30"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "a44623e20b9681a318efdd71c299b6b222ed6f231972bfe2f224ebad6311f0c1"
[[package]]
name = "futures-macro"
version = "0.3.30"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "87750cf4b7a4c0625b1529e4c543c2182106e4dedc60a2a6455e00d212c489ac"
dependencies = [
"proc-macro2",
"quote",
"syn 2.0.60",
]
[[package]]
name = "futures-sink"
version = "0.3.30"
@ -551,10 +595,16 @@ version = "0.3.30"
source = "registry+https://github.com/rust-lang/crates.io-index"
checksum = "3d6401deb83407ab3da39eba7e33987a73c3df0c82b4bb5813ee871c19c41d48"
dependencies = [
"futures-channel",
"futures-core",
"futures-io",
"futures-macro",
"futures-sink",
"futures-task",
"memchr",
"pin-project-lite",
"pin-utils",
"slab",
]
[[package]]
@ -1258,6 +1308,7 @@ dependencies = [
"derive_more",
"either",
"fetch",
"futures",
"serde_json",
"store",
"tracing",

6
lib/fetch/src/client.rs
View file

@ -38,13 +38,13 @@ impl Client {
///
/// Note that in order for the request to be considered valid by most implementations, `key.owner`
/// must equal `payload.actor`.
#[instrument(target = "fetch.delivery", skip_all, fields(activity = payload.id, url = inbox, key = key.id))]
pub async fn deliver(&self, key: &SigningKey, payload: &Activity, inbox: &str) {
#[instrument(target = "fetch.delivery", skip_all, fields(activity = payload.id, url = inbox.as_ref(), key = key.id))]
pub async fn deliver(&self, key: &SigningKey, payload: &Activity, inbox: impl AsRef<str>) {
let system = Subsystem::Delivery;
let body = serde_json::to_string(&payload.to_json_ld()).unwrap();
let mut req = system
.new_request(inbox)
.new_request(inbox.as_ref())
.unwrap()
.method(Method::POST)
.header("content-type", ACTIVITYPUB_TYPE)

1
lib/puppy/Cargo.toml
View file

@ -14,3 +14,4 @@ either = "*"
derive_more = "*"
serde_json = "*"
tracing = "*"
futures = "*"

620
lib/puppy/src/lib.rs
View file

@ -2,7 +2,13 @@
//! you should take a look at [`fetch`].
// Working with result types is such a bitch without these.
#![feature(iterator_try_collect, try_blocks, once_cell_try, box_into_inner)]
#![feature(
iterator_try_collect,
try_blocks,
once_cell_try,
box_into_inner,
type_changing_struct_update
)]
use std::hint::unreachable_unchecked;
@ -336,7 +342,7 @@ pub async fn ingest(cx: &Context, auth: Key, activity: &Activity) -> Result<()>
match object {
Object::Activity(a) => interpret(&cx, a)?,
Object::Actor(a) => cx.run(|tx| actor::create_remote(tx, a).map(void))?,
Object::Note(a) => post::create_post_from_note(cx, a).map(void)?,
Object::Note(a) => cx.run(|tx| post::create_post_from_note(tx, a).map(void))?,
_ => todo!(),
}
}
@ -345,3 +351,613 @@ pub async fn ingest(cx: &Context, auth: Key, activity: &Activity) -> Result<()>
/// Discard the argument.
fn void<T>(_: T) -> () {}
pub mod systems {
//! Logic containment zone.
use fetch::Client;
use store::{Key, Transaction};
use tracing::warn;
/// Allows subsystems to interact with the [fetch] and [store] components.
pub trait Context {
/// Access the transaction.
fn db(&self) -> &Transaction<'_>;
/// Access the federation client.
fn client(&self) -> &Client;
/// Get the ActivityPub domain of this server.
fn domain(&self) -> &str;
/// Format `key` as an object ID.
fn make_object_id(&self, key: Key) -> String {
format!("https://{}/o/{key}", self.domain())
}
/// Check whether we already know about an object.
fn is_known(&self, url: &str) -> bool {
use crate::data::Id;
match self.db().lookup(Id(url.to_string())) {
Ok(Some(_)) => true,
_ => false,
}
}
/// Check whether `url` refers to an object that is considered "local" to this server.
fn is_local(&self, url: &str) -> bool {
use crate::data::{Id, Object};
let Ok(Some(key)) = self.db().lookup(Id(url.to_string())) else {
return false;
};
match self.db().get_mixin(key) {
Ok(Some(Object { local, .. })) => local,
Ok(None) => false,
Err(err) => {
warn!("error while trying to determine origin of {key}: {err}");
false
}
}
}
}
pub mod notification {
//! Manages the delivery of notifications to local users.
use tracing::info;
use crate::Result;
use super::Context;
/// Something that can be sent to a local user as a (push) notification.
pub trait Notification {}
/// Get the notification where it needs to go.
pub fn dispatch<C>(cx: &C, event: &impl Notification) -> Result<()>
where
C: Context,
{
info!("ding!");
Ok(())
}
}
pub mod delivery {
//! A mid-level system for delivering messages to remote servers.
use fetch::{
object::{Activity, Object},
signatures::SigningKey,
};
use futures::{stream::FuturesUnordered, Future, StreamExt as _};
use derive_more::Display;
use store::{arrow::Multi, Key};
use tracing::error;
use crate::{entities::Accept, Error, Result};
use super::Context;
/// Type tag for an activity.
#[derive(Clone, Copy, Display)]
pub enum Tag {
Follow,
Accept,
Reject,
Create,
Delete,
Bite,
}
/// Implemented for types that can represent an activity that can be delivered to a remote server.
pub trait Payload {
/// Construct an [`Activity`] for delivery.
fn prepare<C>(self, cx: &C) -> Result<Activity>
where
C: Context + ?Sized;
/// Call the delivery subsystem to this payload everywhere it needs to go.
///
/// A convenience method to call [`deliver`] as a method instead of a free-standing function.
fn deliver<C>(self, cx: &C) -> impl Future<Output = Result<()>> + Send + Sync
where
Self: Sized + Send + Sync,
C: Context + Send + Sync + ?Sized,
{
deliver(cx, self)
}
}
impl Payload for Accept {
fn prepare<C>(self, cx: &C) -> Result<Activity>
where
C: Context + ?Sized,
{
let (actor, object, tag) = get_activity_data(cx, self.into())?;
Ok(Activity {
id: cx.make_object_id(self.into()),
actor,
object: Box::new(Object::Id { id: object }),
kind: tag.to_string(),
})
}
}
/// Deliver the activity-like payload to all its intended recipients.
pub async fn deliver<C>(cx: &C, payload: impl Payload) -> Result<()>
where
C: Context + ?Sized,
{
let activity = payload.prepare(cx)?;
if !cx.is_local(&activity.id) {
error!("delivery of non-local activity!!");
return Ok(());
}
let signing_key = get_keypair(cx, &activity.actor)?;
get_targets(cx, &activity)?
.into_iter()
.map(|inbox| cx.client().deliver(&signing_key, &activity, inbox))
.collect::<FuturesUnordered<_>>()
.collect::<()>()
.await;
Ok(())
}
/// Calculate the list of inboxes to send the activity to.
fn get_targets<C>(cx: &C, activity: &Activity) -> Result<impl IntoIterator<Item = String>>
where
C: Context + ?Sized,
{
use crate::data::{Channel, Id};
let get_inbox = |id: &str| -> Result<Option<String>> {
let Some(key) = cx.db().lookup(Id(id.to_owned()))? else {
return Ok(None);
};
cx.db()
.get_mixin(key)
.map(|o| o.map(|Channel { inbox }| inbox))
.map_err(Error::Store)
};
match *activity.object {
Object::Id { ref id } => get_inbox(&id),
Object::Activity(ref a) => get_inbox(&a.actor),
Object::Actor(ref a) => Ok(Some(a.inbox.clone())),
Object::Note(ref a) => get_inbox(&a.author),
}
}
/// Get a signing key for the given actor id.
///
/// Will fail if the actor isn't local.
fn get_keypair<C>(cx: &C, actor_id: &str) -> Result<SigningKey>
where
C: Context + ?Sized,
{
use crate::{
actor::{get_signing_key, Actor},
data::Id,
};
let Some(actor_key) = cx.db().lookup(Id(actor_id.to_string()))? else {
panic!("could not get db key for {actor_id}");
};
get_signing_key(cx.db(), Actor { key: actor_key }).map_err(Error::Store)
}
/// Get actor id, the object id, and the type of the activity.
fn get_activity_data<C>(cx: &C, key: Key) -> Result<(String, String, Tag)>
where
C: Context + ?Sized,
{
// TODO: instead of panicking, return a normal error.
use crate::data::{Id, Object, ActivityKind, ObjectKind};
let Some(Object { kind, .. }) = cx.db().get_mixin(key)? else {
panic!("activity must be an object")
};
let Some(Multi { origin, target, .. }) = cx.db().get_arrow_raw(key)? else {
panic!("expected activity to have multi-arrow repr")
};
let Some(Id(object)) = cx.db().get_alias(target)? else {
panic!("expected object of activity to have an id")
};
let Some(Id(actor)) = cx.db().get_alias(origin)? else {
panic!("expected author of activity to have an id")
};
let tag = match kind {
ObjectKind::Activity(tag) => match tag {
ActivityKind::Create => Tag::Create,
ActivityKind::Follow => Tag::Follow,
ActivityKind::Accept => Tag::Accept,
ActivityKind::Reject => Tag::Reject,
ActivityKind::Bite => Tag::Bite,
},
_ => panic!("invalid kind for activity"),
};
Ok((actor, object, tag))
}
}
pub mod ingestion {
//! Processing remote objects to make them part of our local graph.
}
pub mod processor {
//! The structure and interpretation of activity graphs.
//!
//! This is where the magic happens.
//!
//! This module contains the code that assembles and executes a graph of activities. This is a higher
//! level system, that depends on the following sibling systems:
//!
//! - [`following`][super::following]
//! - [`delivery`][super::delivery]
//!
//! Its main purpose is to integrate all the above system in the context of receiving an activity in
//! an inbox, and the subsequent processing that needs to happen. In order to *correctly* interpret an
//! activity, we need to know about the other nodes that it references.
use fetch::{
object::{Activity, Actor, Note, Object},
signatures::SigningKey,
FetchError,
};
use store::Key;
use tracing::{debug, info, trace, warn};
use crate::{data, Result};
use super::{
delivery::{self, Tag},
following, Context,
};
/// Process an incoming activity.
#[tracing::instrument(target = "puppy.processor", skip_all, fields(activity = root.id))]
pub async fn process_incoming<C>(
cx: &C,
on_behalf_of: &SigningKey,
root: Activity,
) -> Result<(Key, Tag)>
where
C: Context,
{
if cx.is_local(&root.id) || cx.is_known(&root.id) {
panic!("could not process activity, it already exists");
}
// Fetch all transitive dependencies of `root`, returned in the order that they need to be processed.
let (actors, notes, activities) =
fetch_dependencies(cx, &root, &on_behalf_of, 3).await?;
trace!("storing actors");
for actor in actors {
store_actor(cx, actor)?;
}
trace!("storing notes");
for note in notes {
store_note(cx, note)?;
}
// Process the activities that have to execute before `activity`. These dependencies are returned
// in the exact order that they need to be applied. `fetch_dependencies` only returns stuff that is
// missing from the graph.
trace!("applying dependency activities");
for dep in activities {
let (key, tag) = apply_activity(cx, dep).await?;
debug!(
dependency_of = root.id,
kind = tag.to_string(),
"processed activity {key}"
);
}
// Now that all activities that this depends on have been executed, we can execute the original
// one.
trace!("executing target activity");
apply_activity(cx, root).await
}
/// Execute the activity.
///
/// # Panics
///
/// This function assumes that everything the activity references by ActivityPub ID is already present in the context.
/// If this is not the case, it will panic.
///
/// Specifically,
#[tracing::instrument(level = "TRACE", target = "puppy.processor", skip_all, fields(activity = activity.id))]
async fn apply_activity<C>(cx: &C, activity: Activity) -> Result<(Key, Tag)>
where
C: Context,
{
use crate::data::{Id, Create};
// Get a key and error out if it does not exist
let get_key = |url: &str| -> Key {
cx.db()
.lookup(data::Id(url.to_string()))
.expect("database should be operable")
.expect("url should already have been inserted")
};
let tag = tagof(&activity);
let key = match tag {
Tag::Follow => {
let requester = get_key(&activity.actor);
let target = get_key(activity.object.id());
let req = following::create_follow_request(cx, requester, target)?;
debug!("created follow request {req}");
// For now, automatically accept follow requests.
if cx.is_local(activity.object.id()) {
debug!("auto-accepting follow request for local actor {target}",);
let accept = following::accept_follow_request(cx, req)?;
if !cx.is_local(&activity.actor) {
debug!("delivering to remote actor");
delivery::deliver(cx, accept).await?;
}
}
req.into()
}
Tag::Accept => {
let req_id = get_key(activity.object.id());
following::accept_follow_request(cx, req_id.into())?.into()
}
Tag::Reject => {
let req_id = get_key(activity.object.id());
following::reject_follow_request(cx, req_id.into())?.into()
}
Tag::Create => {
let id = Key::gen();
let actor = get_key(&activity.actor);
let object = get_key(activity.object.id());
cx.db().add_alias(id, Id(cx.make_object_id(id)))?;
cx.db().create(Create { id, actor, object })?;
id.into()
}
Tag::Delete => todo!(),
Tag::Bite => todo!(),
};
Ok((key, tag))
}
/// Fetch all transitive dependencies of `root` using the given `auth` as the signing authority.
///
/// The `budget` parameter specifies the maximum number of recursive calls.
#[tracing::instrument(target = "puppy.processor", skip_all, fields(budget = budget, target = root.id))]
async fn fetch_dependencies<C>(
cx: &C,
root: &Activity,
auth: &SigningKey,
budget: usize,
) -> Result<(Vec<Actor>, Vec<Note>, Vec<Activity>)>
where
C: Context,
{
let mut actors = Vec::new();
let mut notes = Vec::new();
let mut activities = Vec::new();
for url in [root.actor.as_str(), root.object.id()] {
if cx.is_known(url) {
debug!(parent = root.id, url, "already known, skipping");
continue;
} else {
debug!(parent = root.id, url, budget, "fetching dependency");
}
let json = cx.client().resolve(auth, url).await?;
let object = Object::from_json(json).map_err(FetchError::BadJson)?;
match object {
Object::Id { id } => {
warn!(parent = root.id, url, "could not fetch {id}");
}
Object::Activity(a) if budget == 0 => {
info!(parent = root.id, url, "exceeded budget, skipping");
activities.push(a);
continue;
}
Object::Activity(a) => {
debug!(parent = root.id, url, "fetching dependencies");
// BUG: this won't hit cache because none of the stuff is in there yet.
let (x, y, z) =
Box::pin(fetch_dependencies(cx, &a, auth, budget - 1)).await?;
trace!(
parent = root.id,
url,
"fetch completed, total: {}",
x.len() + y.len() + z.len()
);
actors.extend(x);
notes.extend(y);
activities.extend(z);
activities.push(a);
}
Object::Actor(a) => actors.push(a),
Object::Note(a) => notes.push(a),
}
}
Ok((actors, notes, activities))
}
fn store_actor<C>(cx: &C, actor: Actor) -> Result<()>
where
C: Context,
{
if !cx.is_known(&actor.id) {
crate::actor::create_remote(cx.db(), actor)?;
} else {
debug!("actor {} is already known", actor.id);
}
Ok(())
}
fn store_note<C>(cx: &C, note: Note) -> Result<()>
where
C: Context,
{
if !cx.is_known(&note.id) {
crate::post::create_post_from_note(cx.db(), note)?;
} else {
debug!("note {} is already known", note.id);
}
Ok(())
}
/// Get the tag of the activity.
fn tagof(a: &Activity) -> Tag {
match a.kind.as_str() {
"Create" => Tag::Create,
"Delete" => Tag::Delete,
"Follow" => Tag::Follow,
"Accept" => Tag::Accept,
"Reject" => Tag::Reject,
"Bite" => Tag::Bite,
_ => todo!(),
}
}
}
pub mod timelines {
//! Manages the rendering of timelines.
}
pub mod following {
//! Follow requests and management thereof.
use store::Key;
use super::Context;
use crate::{
entities::{Accept, FollowRequest, Reject, Undo},
Result,
};
/// Create a follow request.
pub fn create_follow_request<C>(cx: &C, follower: Key, target: Key) -> Result<FollowRequest>
where
C: Context + ?Sized,
{
Ok(Key::gen().into())
}
/// Cancel a follow request.
///
/// If the follow request was already accepted, the follow request's target is unfollowed by the actor. Otherwise,
/// the follow request is withdrawn.
///
/// This creates a new [`Undo`] entry in the database to which data may be attached.
pub fn cancel_follow_request<C>(cx: &C, req: FollowRequest) -> Result<Undo>
where
C: Context + ?Sized,
{
Ok(Key::gen().into())
}
/// Apply the changes related to accepting a follow request to the social graph and create a new node representing
/// the event.
pub fn accept_follow_request<C>(cx: &C, req: FollowRequest) -> Result<Accept>
where
C: Context + ?Sized,
{
Ok(Key::gen().into())
}
/// Apply the changes related to rejecting a follow request to the social graph and create a new node representing
/// the event.
pub fn reject_follow_request<C>(cx: &C, req: FollowRequest) -> Result<Reject>
where
C: Context + ?Sized,
{
Ok(Key::gen().into())
}
}
pub mod reverse {
//! Undoing operations.
//!
//! This module defines the behavior of the [`Undo`] activity.
use crate::entities::{FollowRequest, Undo};
use super::{following, Context};
/// Describes objects which have a "revert" operation defined (that is, they can be the target of an [`Undo`] activity).
pub trait Reversible {
/// Undo `self` and generate a corresponding [`Undo`] object recording this fact.
fn revert(&self, cx: &dyn Context) -> crate::Result<Undo>;
}
impl Reversible for FollowRequest {
/// Withdraw a follow request if it wasn't yet accepted, or unfollow someone.
fn revert(&self, cx: &dyn Context) -> crate::Result<Undo> {
following::cancel_follow_request(cx, *self)
}
}
}
}
pub mod entities {
//! Virtual data types composed from [components] and operated on by [systems].
//!
//! [components]: crate::components
//! [systems]: crate::systems
use store::Key;
use derive_more::{From, Into, Display};
#[derive(Clone, Copy, Debug, From, Into, Display)]
pub struct Poster(Key);
#[derive(Clone, Copy, Debug, From, Into, Display)]
pub struct Server(Key);
#[derive(Clone, Copy, Debug, From, Into, Display)]
pub struct Post(Key);
/// Represents a `Bite` activity.
#[derive(Clone, Copy, Debug, From, Into, Display)]
pub struct Bite(Key);
/// Represents an `Undo` activity.
#[derive(Clone, Copy, Debug, From, Into, Display)]
pub struct Undo(Key);
/// Represents an `Accept` activity.
#[derive(Clone, Copy, Debug, From, Into, Display)]
pub struct Accept(Key);
/// Represents a `Reject` activity.
#[derive(Clone, Copy, Debug, From, Into, Display)]
pub struct Reject(Key);
/// Represents a `Create` activity.
#[derive(Clone, Copy, Debug, From, Into, Display)]
pub struct Create(Key);
/// Represents a `Follow` activity.
///
/// Also see the [`following`][crate::systems::following] module, which defines the logic for following, follow requests
/// and other related stuff.
#[derive(Clone, Copy, Debug, From, Into, Display)]
pub struct FollowRequest(Key);
#[derive(Clone, Copy, Debug, From, Into, Display)]
pub struct PublicKey(Key);
/// A key newtype that represents an object.
pub trait Entity: Into<Key> + From<Key> + Copy {}
impl<T> Entity for T where T: Into<Key> + From<Key> + Copy {}
}
pub mod components {}

38
lib/puppy/src/post.rs
View file

@ -152,29 +152,27 @@ pub fn create_local_post(
}
/// Assumes all objects referenced already exist.
#[tracing::instrument(skip(cx))]
pub fn create_post_from_note(cx: &Context, note: Note) -> crate::Result<Post> {
cx.run(|tx| {
let Some(author) = tx.lookup(Id(note.author))? else {
panic!("needed author to already exist")
};
#[tracing::instrument(skip(tx))]
pub fn create_post_from_note(tx: &Transaction<'_>, note: Note) -> crate::Result<Post> {
let Some(author) = tx.lookup(Id(note.author))? else {
panic!("needed author to already exist")
};
let key = Key::gen();
let key = Key::gen();
tx.add_alias(key, Id(note.id.clone()))?;
tx.create(AuthorOf { object: key, author })?;
tx.add_mixin(key, Content {
content: note.content,
warning: note.summary,
})?;
tx.add_mixin(key, data::Object {
kind: ObjectKind::Notelike(note.kind),
id: Id(note.id),
local: false,
})?;
tx.add_alias(key, Id(note.id.clone()))?;
tx.create(AuthorOf { object: key, author })?;
tx.add_mixin(key, Content {
content: note.content,
warning: note.summary,
})?;
tx.add_mixin(key, data::Object {
kind: ObjectKind::Notelike(note.kind),
id: Id(note.id),
local: false,
})?;
Ok(Post { key })
})
Ok(Post { key })
}
#[tracing::instrument(skip(cx))]

6
lib/store/src/arrow.rs
View file

@ -222,11 +222,15 @@ impl Transaction<'_> {
where
A: Arrow<Kind = Multi>,
{
Ok(self.get_arrow_raw(key)?.map(A::from))
}
/// Construct the arrow from its identifier.
pub fn get_arrow_raw(&self, key: Key) -> Result<Option<Multi>> {
let arrow = self
.open(crate::types::MULTIEDGE_HEADERS)
.get(key)?
.map(|v| Key::split(v.as_ref()))
.map(|(origin, target)| A::from(Multi { origin, target, identity: key }));
.map(|(origin, target)| Multi { origin, target, identity: key });
Ok(arrow)
}
}

3
lib/store/src/key.rs
View file

@ -3,13 +3,14 @@ use std::{
str::FromStr,
};
use bincode::{Decode, Encode};
use chrono::{DateTime, Utc};
use ulid::Ulid;
use crate::StoreError;
/// A unique identifier for vertices in the database.
#[derive(Clone, Copy, Eq, PartialEq, Ord, PartialOrd, Hash)]
#[derive(Clone, Copy, Eq, PartialEq, Ord, PartialOrd, Hash, Encode, Decode)]
pub struct Key(pub(crate) [u8; 16]);
impl Key {

28
lib/store/src/lib.rs
View file

@ -68,7 +68,7 @@ pub struct Batch {
}
impl Store {
/// Run a [transaction][Transaction].
/// Run a [transaction][Transaction] and ensure that it is either committed or rolled back.
///
/// In a transaction, either all writes succeed, or the transaction is aborted and the changes are not
/// recorded. Changes made inside a transaction can be read from within that transaction before they are
@ -85,15 +85,20 @@ impl Store {
store: &self,
};
let r = f(&tx);
if let Err(e) = if r.is_err() {
tx.inner.rollback()
if r.is_err() {
tx.cancel()?;
} else {
tx.inner.commit()
} {
return Err(E::from(StoreError::Internal(e)));
tx.commit()?;
}
r
}
/// Begin a transaction.
pub fn start(&self) -> Transaction<'_> {
Transaction {
inner: self.inner.transaction(),
store: &self,
}
}
/// Apply a batch of changes atomically.
pub fn apply(&self, batch: Batch) -> Result<()> {
self.inner.write(batch.inner.into_inner())?;
@ -132,6 +137,17 @@ impl Store {
}
}
impl<'db> Transaction<'db> {
/// Complete the transaction successfully.
pub fn commit(self) -> Result<(), StoreError> {
self.inner.commit().map_err(StoreError::from)
}
/// Cancel the transaction.
pub fn cancel(self) -> Result<(), StoreError> {
self.inner.rollback().map_err(StoreError::from)
}
}
/// A shorthand for committing a [`Transaction`] (because I think `Ok(())` is ugly).
pub const OK: Result<()> = Ok(());