Struct Metadata

Source

pub struct Metadata(pub BTreeMap<String, Ipld>);

Expand description

The metadata of a node in the WNFS file system.

§Examples

use wnfs_common::Metadata;
use chrono::Utc;

let metadata = Metadata::new(Utc::now());

println!("{:?}", metadata);

Tuple Fields§

§0: BTreeMap<String, Ipld>

Implementations§

Source §

impl Metadata

Source

pub fn new(time: DateTime<Utc>) -> Self

Creates a new metadata.

§Examples

use wnfs_common::Metadata;
use chrono::Utc;

let metadata = Metadata::new(Utc::now());

println!("{:?}", metadata);

Source

pub fn upsert_mtime(&mut self, time: DateTime<Utc>)

Updates modified time.

§Examples

use wnfs_common::Metadata;
use chrono::{Utc, TimeZone, Duration};

let mut metadata = Metadata::new(Utc::now());
let time = Utc::now() + Duration::days(1);

metadata.upsert_mtime(time);

let imprecise_time = Utc.timestamp_opt(time.timestamp(), 0).single();
assert_eq!(metadata.get_modified(), imprecise_time);

Source

pub fn get_created(&self) -> Option<DateTime<Utc>>

Returns the created time.

§Examples

use wnfs_common::Metadata;
use chrono::{Utc, TimeZone};

let time = Utc::now();
let metadata = Metadata::new(time);

let imprecise_time = Utc.timestamp_opt(time.timestamp(), 0).single();
assert_eq!(metadata.get_created(), imprecise_time);

Will return None if there’s no created metadata on the node or if it’s not a second-based POSIX timestamp integer.

Source

pub fn get_modified(&self) -> Option<DateTime<Utc>>

Returns the modified time.

§Examples

use wnfs_common::Metadata;
use chrono::{Utc, TimeZone};

let time = Utc::now();
let metadata = Metadata::new(time);

let imprecise_time = Utc.timestamp_opt(time.timestamp(), 0).single();
assert_eq!(metadata.get_modified(), imprecise_time);

Will return None if there’s no created metadata on the node or if it’s not a second-based POSIX timestamp integer.

Source

pub fn put(&mut self, key: &str, value: Ipld) -> Option<Ipld>

Inserts a key-value pair into the metadata. If the key already existed, the value is updated, and the old value is returned.

§Examples

use wnfs_common::Metadata;
use chrono::Utc;
use ipld_core::ipld::Ipld;

let mut metadata = Metadata::new(Utc::now());
metadata.put("foo", Ipld::String("bar".into()));
assert_eq!(metadata.0.get("foo"), Some(&Ipld::String("bar".into())));
metadata.put("foo", Ipld::String("baz".into()));
assert_eq!(metadata.0.get("foo"), Some(&Ipld::String("baz".into())));

Returns (self, old_value), where old_value is None if the key did not exist prior to this call.

Source

pub fn get(&self, key: &str) -> Option<&Ipld>

Returns metadata value behind given key.

Source

pub fn put_serializable( &mut self, key: &str, value: impl Serialize, ) -> Result<Option<Ipld>>

Serializes and inserts given value at given key in metadata.

Source

pub fn get_deserializable<D: DeserializeOwned>( &self, key: &str, ) -> Option<Result<D>>

Returns deserialized metadata value behind given key.

Source

pub fn delete(&mut self, key: &str) -> Option<Ipld>

Deletes a key from the metadata.

§Examples

use wnfs_common::Metadata;
use chrono::Utc;
use ipld_core::ipld::Ipld;

let mut metadata = Metadata::new(Utc::now());
metadata.put("foo", Ipld::String("bar".into()));
assert_eq!(metadata.0.get("foo"), Some(&Ipld::String("bar".into())));
metadata.delete("foo");
assert_eq!(metadata.0.get("foo"), None);

Returns Some<Ipld> if the key existed prior to this call, otherwise None.

Source

pub fn update(&mut self, other: &Self)

Updates this metadata with the contents of another metadata. merge strategy is to take theirs.

§Examples

use wnfs_common::Metadata;
use chrono::Utc;
use ipld_core::ipld::Ipld;

let mut metadata1 = Metadata::new(Utc::now());
metadata1.put("foo", Ipld::String("bar".into()));
let mut metadata2 = Metadata::new(Utc::now());
metadata2.put("foo", Ipld::String("baz".into()));
metadata1.update(&metadata2);
assert_eq!(metadata1.0.get("foo"), Some(&Ipld::String("baz".into())));

Source

pub fn tie_break_with(&mut self, other: &Self) -> Result<()>

Tie break this node with another one. Used for conflict reconciliation. We don’t merge the two metadata maps together (yet), instead we compare their hashes. The one with the lower hash survives.