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//! Contains the types for read concerns and write concerns.
#[cfg(test)]
mod test;
use std::time::Duration;
use serde::{Deserialize, Deserializer, Serialize, Serializer};
use serde_with::skip_serializing_none;
use typed_builder::TypedBuilder;
use crate::{
bson::{doc, serde_helpers, Timestamp},
error::{ErrorKind, Result},
serde_util,
};
/// Specifies the consistency and isolation properties of read operations from replica sets and
/// replica set shards.
///
/// See the documentation [here](https://www.mongodb.com/docs/manual/reference/read-concern/) for more
/// information about read concerns.
#[skip_serializing_none]
#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
#[serde(rename_all = "camelCase")]
#[non_exhaustive]
pub struct ReadConcern {
/// The level of the read concern.
pub level: ReadConcernLevel,
}
impl ReadConcern {
/// A `ReadConcern` with level `ReadConcernLevel::Local`.
pub const LOCAL: ReadConcern = ReadConcern {
level: ReadConcernLevel::Local,
};
/// A `ReadConcern` with level `ReadConcernLevel::Majority`.
pub const MAJORITY: ReadConcern = ReadConcern {
level: ReadConcernLevel::Majority,
};
/// A `ReadConcern` with level `ReadConcernLevel::Linearizable`.
pub const LINEARIZABLE: ReadConcern = ReadConcern {
level: ReadConcernLevel::Linearizable,
};
/// A `ReadConcern` with level `ReadConcernLevel::Available`.
pub const AVAILABLE: ReadConcern = ReadConcern {
level: ReadConcernLevel::Available,
};
/// A `ReadConcern` with level `ReadConcernLevel::Snapshot`.
pub const SNAPSHOT: ReadConcern = ReadConcern {
level: ReadConcernLevel::Snapshot,
};
}
/// An internal-only read concern type that allows the omission of a "level" as well as
/// specification of "atClusterTime" and "afterClusterTime".
#[skip_serializing_none]
#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
#[serde(rename_all = "camelCase")]
#[serde(rename = "readConcern")]
pub(crate) struct ReadConcernInternal {
/// The level of the read concern.
pub(crate) level: Option<ReadConcernLevel>,
/// The snapshot read timestamp.
pub(crate) at_cluster_time: Option<Timestamp>,
/// The time of most recent operation using this session.
/// Used for providing causal consistency.
pub(crate) after_cluster_time: Option<Timestamp>,
}
impl ReadConcern {
/// Creates a read concern with level "majority".
/// See the specific documentation for this read concern level [here](https://www.mongodb.com/docs/manual/reference/read-concern-majority/).
pub fn majority() -> Self {
ReadConcernLevel::Majority.into()
}
/// Creates a read concern with level "local".
/// See the specific documentation for this read concern level [here](https://www.mongodb.com/docs/manual/reference/read-concern-local/).
pub fn local() -> Self {
ReadConcernLevel::Local.into()
}
/// Creates a read concern with level "linearizable".
/// See the specific documentation for this read concern level [here](https://www.mongodb.com/docs/manual/reference/read-concern-linearizable/).
pub fn linearizable() -> Self {
ReadConcernLevel::Linearizable.into()
}
/// Creates a read concern with level "available".
/// See the specific documentation for this read concern level [here](https://www.mongodb.com/docs/manual/reference/read-concern-available/).
pub fn available() -> Self {
ReadConcernLevel::Available.into()
}
/// Creates a read concern with level "snapshot".
/// See the specific documentation for this read concern level [here](https://www.mongodb.com/docs/manual/reference/read-concern-snapshot/).
pub fn snapshot() -> Self {
ReadConcernLevel::Snapshot.into()
}
/// Creates a read concern with a custom read concern level. This is present to provide forwards
/// compatibility with any future read concerns which may be added to new versions of
/// MongoDB.
pub fn custom(level: String) -> Self {
ReadConcernLevel::from_str(level.as_str()).into()
}
#[cfg(test)]
pub(crate) fn serialize_for_client_options<S>(
read_concern: &Option<ReadConcern>,
serializer: S,
) -> std::result::Result<S::Ok, S::Error>
where
S: Serializer,
{
#[derive(Serialize)]
struct ReadConcernHelper<'a> {
readconcernlevel: &'a str,
}
let state = read_concern.as_ref().map(|concern| ReadConcernHelper {
readconcernlevel: concern.level.as_str(),
});
state.serialize(serializer)
}
}
impl From<ReadConcern> for ReadConcernInternal {
fn from(rc: ReadConcern) -> Self {
ReadConcernInternal {
level: Some(rc.level),
at_cluster_time: None,
after_cluster_time: None,
}
}
}
impl From<ReadConcernLevel> for ReadConcern {
fn from(level: ReadConcernLevel) -> Self {
Self { level }
}
}
/// Specifies the level consistency and isolation properties of a given `ReadCocnern`.
///
/// See the documentation [here](https://www.mongodb.com/docs/manual/reference/read-concern/) for more
/// information about read concerns.
#[derive(Clone, Debug, PartialEq)]
#[non_exhaustive]
pub enum ReadConcernLevel {
/// See the specific documentation for this read concern level [here](https://www.mongodb.com/docs/manual/reference/read-concern-local/).
Local,
/// See the specific documentation for this read concern level [here](https://www.mongodb.com/docs/manual/reference/read-concern-majority/).
Majority,
/// See the specific documentation for this read concern level [here](https://www.mongodb.com/docs/manual/reference/read-concern-linearizable/).
Linearizable,
/// See the specific documentation for this read concern level [here](https://www.mongodb.com/docs/manual/reference/read-concern-available/).
Available,
/// See the specific documentation for this read concern level [here](https://www.mongodb.com/docs/manual/reference/read-concern-snapshot/).
Snapshot,
/// Specify a custom read concern level. This is present to provide forwards compatibility with
/// any future read concerns which may be added to new versions of MongoDB.
Custom(String),
}
impl ReadConcernLevel {
pub(crate) fn from_str(s: &str) -> Self {
match s {
"local" => ReadConcernLevel::Local,
"majority" => ReadConcernLevel::Majority,
"linearizable" => ReadConcernLevel::Linearizable,
"available" => ReadConcernLevel::Available,
"snapshot" => ReadConcernLevel::Snapshot,
s => ReadConcernLevel::Custom(s.to_string()),
}
}
/// Gets the string representation of the `ReadConcernLevel`.
pub(crate) fn as_str(&self) -> &str {
match self {
ReadConcernLevel::Local => "local",
ReadConcernLevel::Majority => "majority",
ReadConcernLevel::Linearizable => "linearizable",
ReadConcernLevel::Available => "available",
ReadConcernLevel::Snapshot => "snapshot",
ReadConcernLevel::Custom(ref s) => s,
}
}
}
impl<'de> Deserialize<'de> for ReadConcernLevel {
fn deserialize<D: Deserializer<'de>>(deserializer: D) -> std::result::Result<Self, D::Error> {
let s = String::deserialize(deserializer)?;
Ok(ReadConcernLevel::from_str(&s))
}
}
impl Serialize for ReadConcernLevel {
fn serialize<S>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error>
where
S: Serializer,
{
self.as_str().serialize(serializer)
}
}
/// Specifies the level of acknowledgement requested from the server for write operations.
///
/// See the documentation [here](https://www.mongodb.com/docs/manual/reference/write-concern/) for more
/// information about write concerns.
#[skip_serializing_none]
#[derive(Clone, Debug, Default, PartialEq, TypedBuilder, Serialize, Deserialize)]
#[builder(field_defaults(default, setter(into)))]
#[non_exhaustive]
pub struct WriteConcern {
/// Requests acknowledgement that the operation has propagated to a specific number or variety
/// of servers.
pub w: Option<Acknowledgment>,
/// Specifies a time limit for the write concern. If an operation has not propagated to the
/// requested level within the time limit, an error will return.
///
/// Note that an error being returned due to a write concern error does not imply that the
/// write would not have finished propagating if allowed more time to finish, and the
/// server will not roll back the writes that occurred before the timeout was reached.
#[serde(rename = "wtimeout", alias = "wtimeoutMS")]
#[serde(serialize_with = "serde_util::serialize_duration_option_as_int_millis")]
#[serde(deserialize_with = "serde_util::deserialize_duration_option_from_u64_millis")]
#[serde(default)]
pub w_timeout: Option<Duration>,
/// Requests acknowledgement that the operation has propagated to the on-disk journal.
#[serde(rename = "j", alias = "journal")]
pub journal: Option<bool>,
}
impl WriteConcern {
// Can't use `Default::default()` in const contexts yet :(
const DEFAULT: WriteConcern = WriteConcern {
w: None,
w_timeout: None,
journal: None,
};
/// A `WriteConcern` requesting `Acknowledgment::Majority`.
pub const MAJORITY: WriteConcern = WriteConcern {
w: Some(Acknowledgment::Majority),
..WriteConcern::DEFAULT
};
}
/// The type of the `w` field in a [`WriteConcern`](struct.WriteConcern.html).
#[derive(Clone, Debug, PartialEq)]
#[non_exhaustive]
pub enum Acknowledgment {
/// Requires acknowledgement that the write has reached the specified number of nodes.
///
/// Note: specifying 0 here indicates that the write concern is unacknowledged, which is
/// currently unsupported and will result in an error during operation execution.
Nodes(u32),
/// Requires acknowledgement that the write has reached the majority of nodes.
Majority,
/// Requires acknowledgement according to the given custom write concern. See [here](https://www.mongodb.com/docs/manual/tutorial/configure-replica-set-tag-sets/#tag-sets-and-custom-write-concern-behavior)
/// for more information.
Custom(String),
}
impl Serialize for Acknowledgment {
fn serialize<S>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error>
where
S: Serializer,
{
match self {
Acknowledgment::Majority => serializer.serialize_str("majority"),
Acknowledgment::Nodes(n) => serde_helpers::serialize_u32_as_i32(n, serializer),
Acknowledgment::Custom(name) => serializer.serialize_str(name),
}
}
}
impl<'de> Deserialize<'de> for Acknowledgment {
fn deserialize<D>(deserializer: D) -> std::result::Result<Self, D::Error>
where
D: Deserializer<'de>,
{
#[derive(Deserialize)]
#[serde(untagged)]
enum IntOrString {
Int(u32),
String(String),
}
match IntOrString::deserialize(deserializer)? {
IntOrString::String(s) => Ok(s.into()),
IntOrString::Int(i) => Ok(i.into()),
}
}
}
impl From<u32> for Acknowledgment {
fn from(i: u32) -> Self {
Acknowledgment::Nodes(i)
}
}
impl From<String> for Acknowledgment {
fn from(s: String) -> Self {
if s == "majority" {
Acknowledgment::Majority
} else {
Acknowledgment::Custom(s)
}
}
}
impl WriteConcern {
pub(crate) fn is_acknowledged(&self) -> bool {
self.w != Some(Acknowledgment::Nodes(0)) || self.journal == Some(true)
}
/// Whether the write concern was created with no values specified. If true, the write concern
/// should be considered the server's default.
pub(crate) fn is_empty(&self) -> bool {
self.w.is_none() && self.w_timeout.is_none() && self.journal.is_none()
}
/// Validates that the write concern. A write concern is invalid if both the `w` field is 0
/// and the `j` field is `true`.
pub(crate) fn validate(&self) -> Result<()> {
if self.w == Some(Acknowledgment::Nodes(0)) && self.journal == Some(true) {
return Err(ErrorKind::InvalidArgument {
message: "write concern cannot have w=0 and j=true".to_string(),
}
.into());
}
if let Some(w_timeout) = self.w_timeout {
if w_timeout < Duration::from_millis(0) {
return Err(ErrorKind::InvalidArgument {
message: "write concern `w_timeout` field cannot be negative".to_string(),
}
.into());
}
}
Ok(())
}
#[cfg(test)]
pub(crate) fn serialize_for_client_options<S>(
write_concern: &Option<WriteConcern>,
serializer: S,
) -> std::result::Result<S::Ok, S::Error>
where
S: Serializer,
{
#[derive(Serialize)]
struct WriteConcernHelper<'a> {
w: Option<&'a Acknowledgment>,
#[serde(serialize_with = "serde_util::serialize_duration_option_as_int_millis")]
wtimeoutms: Option<Duration>,
journal: Option<bool>,
}
let state = write_concern.as_ref().map(|concern| WriteConcernHelper {
w: concern.w.as_ref(),
wtimeoutms: concern.w_timeout,
journal: concern.journal,
});
state.serialize(serializer)
}
}