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//! Provides undo-redo functionality with static dispatch and manual command merging.
//!
//! * [Record] provides a stack based undo-redo functionality.
//! * [History] provides a tree based undo-redo functionality that allows you to jump between different branches.
//! * [Queue] wraps a [Record] or [History] and provides batch queue functionality.
//! * [Checkpoint] wraps a [Record] or [History] and provides checkpoint functionality.
//! * Commands can be merged using the [`merge`] method.
//! When two commands are merged, undoing and redoing them are done in a single step.
//! * Configurable display formatting is provided through the [Display] structure.
//! * Time stamps and time travel is provided when the `chrono` feature is enabled.
//! * Serialization and deserialization is provided when the `serde` feature is enabled.
//!
//! [Record]: struct.Record.html
//! [History]: struct.History.html
//! [Queue]: struct.Queue.html
//! [Checkpoint]: struct.Checkpoint.html
//! [Display]: struct.Display.html
//! [`merge`]: trait.Command.html#method.merge
#![doc(html_root_url = "https://docs.rs/redo/0.29.1")]
#![deny(
bad_style,
bare_trait_objects,
missing_debug_implementations,
missing_docs,
unused_import_braces,
unused_qualifications,
unsafe_code,
unstable_features
)]
extern crate bitflags;
#[cfg(feature = "chrono")]
extern crate chrono;
extern crate colored;
extern crate rustc_hash;
#[cfg(feature = "serde")]
#[macro_use]
extern crate serde;
mod checkpoint;
mod display;
mod history;
mod queue;
mod record;
#[cfg(feature = "chrono")]
use chrono::{DateTime, Utc};
use std::{error::Error as StdError, fmt};
pub use checkpoint::Checkpoint;
pub use display::Display;
pub use history::{History, HistoryBuilder};
pub use queue::Queue;
pub use record::{Record, RecordBuilder};
/// Base functionality for all commands.
pub trait Command<R> {
/// The error type.
type Error;
/// Applies the command on the receiver and returns `Ok` if everything went fine,
/// and `Err` if something went wrong.
fn apply(&mut self, receiver: &mut R) -> Result<(), Self::Error>;
/// Restores the state of the receiver as it was before the command was applied
/// and returns `Ok` if everything went fine, and `Err` if something went wrong.
fn undo(&mut self, receiver: &mut R) -> Result<(), Self::Error>;
/// Reapplies the command on the receiver and return `Ok` if everything went fine,
/// and `Err` if something went wrong.
///
/// The default implementation uses the [`apply`] implementation.
///
/// [`apply`]: trait.Command.html#tymethod.apply
#[inline]
fn redo(&mut self, receiver: &mut R) -> Result<(), Self::Error> {
self.apply(receiver)
}
/// Used for manual merging of two commands.
///
/// # Examples
/// ```
/// # use redo::*;
/// #[derive(Debug)]
/// struct Add(String);
///
/// impl Command<String> for Add {
/// type Error = ();
///
/// fn apply(&mut self, s: &mut String) -> Result<(), ()> {
/// s.push_str(&self.0);
/// Ok(())
/// }
///
/// fn undo(&mut self, s: &mut String) -> Result<(), ()> {
/// let len = s.len() - self.0.len();
/// s.truncate(len);
/// Ok(())
/// }
///
/// fn merge(&mut self, Add(s): Self) -> Merge<Self> {
/// self.0.push_str(&s);
/// Merge::Yes
/// }
/// }
///
/// fn main() -> Result<(), Error<String, Add>> {
/// let mut record = Record::default();
/// // The `a`, `b`, and `c` commands are merged.
/// record.apply(Add("a".into()))?;
/// record.apply(Add("b".into()))?;
/// record.apply(Add("c".into()))?;
/// assert_eq!(record.as_receiver(), "abc");
/// // Calling `undo` once will undo all the merged commands.
/// record.undo().unwrap()?;
/// assert_eq!(record.as_receiver(), "");
/// // Calling `redo` once will redo all the merged commands.
/// record.redo().unwrap()?;
/// assert_eq!(record.as_receiver(), "abc");
/// Ok(())
/// }
/// ```
#[inline]
fn merge(&mut self, command: Self) -> Merge<Self>
where
Self: Sized,
{
Merge::No(command)
}
}
/// The signal sent when the record, the history, or the receiver changes.
///
/// When one of these states changes, they will send a corresponding signal to the user.
/// For example, if the record can no longer redo any commands, it sends a `Redo(false)`
/// signal to tell the user.
#[derive(Copy, Clone, Debug, Hash, Ord, PartialOrd, Eq, PartialEq)]
pub enum Signal {
/// Says if the record can undo.
///
/// This signal will be emitted when the records ability to undo changes.
Undo(bool),
/// Says if the record can redo.
///
/// This signal will be emitted when the records ability to redo changes.
Redo(bool),
/// Says if the receiver is in a saved state.
///
/// This signal will be emitted when the record enters or leaves its receivers saved state.
Saved(bool),
/// Says if the current command has changed.
///
/// This signal will be emitted when the cursor has changed. This includes
/// when two commands have been merged, in which case `old == new`.
Cursor {
/// The old cursor.
old: usize,
/// The new cursor.
new: usize,
},
/// Says if the current branch, or root, has changed.
///
/// This is only emitted from `History`.
Root {
/// The old root.
old: usize,
/// The new root.
new: usize,
},
}
/// The result of merging two commands.
#[derive(Copy, Clone, Debug, Hash, Ord, PartialOrd, Eq, PartialEq)]
pub enum Merge<C> {
/// The commands have been merged.
Yes,
/// The commands have not been merged.
No(C),
/// The two commands cancels each other out. This removes both commands.
Annul,
}
/// A position in a history tree.
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
#[derive(Copy, Clone, Debug, Default, Hash, Ord, PartialOrd, Eq, PartialEq)]
struct At {
branch: usize,
cursor: usize,
}
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
#[derive(Debug)]
struct Meta<C> {
command: C,
#[cfg(feature = "chrono")]
timestamp: DateTime<Utc>,
}
impl<C> From<C> for Meta<C> {
#[inline]
fn from(command: C) -> Self {
Meta {
command,
#[cfg(feature = "chrono")]
timestamp: Utc::now(),
}
}
}
impl<R, C: Command<R>> Command<R> for Meta<C> {
type Error = C::Error;
#[inline]
fn apply(&mut self, receiver: &mut R) -> Result<(), <Self as Command<R>>::Error> {
self.command.apply(receiver)
}
#[inline]
fn undo(&mut self, receiver: &mut R) -> Result<(), <Self as Command<R>>::Error> {
self.command.undo(receiver)
}
#[inline]
fn redo(&mut self, receiver: &mut R) -> Result<(), <Self as Command<R>>::Error> {
self.command.redo(receiver)
}
#[inline]
fn merge(&mut self, command: Self) -> Merge<Self>
where
Self: Sized,
{
match self.command.merge(command.command) {
Merge::Yes => Merge::Yes,
Merge::No(command) => Merge::No(Meta::from(command)),
Merge::Annul => Merge::Annul,
}
}
}
impl<C: fmt::Display> fmt::Display for Meta<C> {
#[inline]
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
(&self.command as &dyn fmt::Display).fmt(f)
}
}
/// An error which holds the command that caused it.
pub struct Error<R, C: Command<R>> {
meta: Meta<C>,
error: C::Error,
}
impl<R, C: Command<R>> Error<R, C> {
/// Returns a new error.
#[inline]
fn new(meta: Meta<C>, error: C::Error) -> Error<R, C> {
Error { meta, error }
}
}
impl<R, C: Command<R>> Error<R, C> {
/// Returns a reference to the command that caused the error.
#[inline]
pub fn command(&self) -> &C {
&self.meta.command
}
/// Returns the command that caused the error.
#[inline]
pub fn into_command(self) -> C {
self.meta.command
}
}
impl<R, C: Command<R> + fmt::Debug> fmt::Debug for Error<R, C>
where
C::Error: fmt::Debug,
{
#[inline]
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.debug_struct("Error")
.field("meta", &self.meta)
.field("error", &self.error)
.finish()
}
}
impl<R, C: Command<R>> fmt::Display for Error<R, C>
where
C::Error: fmt::Display,
{
#[inline]
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
(&self.error as &dyn fmt::Display).fmt(f)
}
}
impl<R, C: Command<R>> StdError for Error<R, C>
where
C: fmt::Debug,
C::Error: StdError,
{
#[inline]
fn description(&self) -> &str {
self.error.description()
}
#[inline]
fn cause(&self) -> Option<&dyn StdError> {
self.error.cause()
}
}