Crate journalmap 

Journaling data storage types for easy version control and undo + redo

journalmap, which was originally made for my side hustle Mjolnir , is a crate meant to provide analog to common data storage types with built-in journaling, meaning each write transaction is recorded so that you can easily undo and redo operations. The end user treats these data types like you would a normal Vec or HashMap, except they can add “tags”, basically generic markers that can be traveled to, to either undo a change, redo a change, or check out a previous version of the data.

Example

Below is an example of a JournalVec.

use journalmap::JournalVec;

fn main() {
   let mut rsvp: JournalVec<&'static str, _> = JournalVec::new();

    // Always add a tag at the start
    rsvp.append_tag("start").unwrap();

    rsvp.push("Sarah");
    rsvp.push("John");
    rsvp.push("Mariah");
    rsvp.insert(1, "Steve");

    rsvp.append_tag("middle").unwrap();

    rsvp.pop();
    rsvp.remove(1);

    rsvp.append_tag("end").unwrap();

     // Now let's reverse it and watch our changes be undone...
    rsvp.reverse_to_next();

    assert_eq!(rsvp.as_slice(), &["Sarah", "Steve", "John", "Mariah"]);

    // We can also redo the changes we've applied
    rsvp.forward_to_tag(&"end");

    assert_eq!(rsvp.as_slice(), &["Sarah", "John"]);

    rsvp.reverse_to_next();

    // Inserting a new entry truncates the future so we can no longer
    // re-do the changes we've undone
    rsvp.push("Omar");
    rsvp.append_tag("end").unwrap();

    assert_eq!(rsvp.as_slice(), &["Sarah", "Steve", "John", "Mariah", "Omar"]);
}

Flags

• serde - enables serde-based serialization and deserialization of journals.

Structs

JournalMap

Journaling HashMap. Each transaction is recorded to the journal and can be undone and redone.

JournalMapJournal

An extracted journal from a JournalMap. Used for storage purposes: if you want to serialize a JournalMap for later, you want to extract a JournalMapJournal and then serialize said journal.

JournalSet

Journaling HashSet. Each transaction is recorded to the journal and can be undone and redone.

JournalSetJournal

An extracted journal from a JournalSet. Used for storage purposes: if you want to serialize a JournalSet for later, you want to extract a JournalSetJournal and then serialize said journal.

JournalVec

Journaling Vector. Each transaction is recorded to the journal and can be undone and redone.

JournalVecJournal

An extracted journal from a JournalVec. Used for storage purposes: if you want to serialize a JournalVec for later, you want to extract a JournalVecJournal and then serialize said journal.

Enums

JournalError