Struct ChangeTracker 

pub struct ChangeTracker { /* private fields */ }

Concrete helper that stores original, current, and previous attribute values.

Implementations

impl ChangeTracker

pub fn new() -> Self

Creates an empty change tracker.

pub fn track_change(&mut self, name: &str, old: Value, new: Value)

Tracks a change from old to new for the named attribute.

If the attribute has already changed, the original value is preserved. If new matches the original value, the attribute is removed from the current change set.

pub fn changed(&self) -> bool

Returns true when at least one attribute is currently changed.

pub fn changes(&self) -> &HashMap<String, [Value; 2]>

Returns the current unsaved changes.

pub fn previous_changes(&self) -> &HashMap<String, [Value; 2]>

Returns the previously applied changes.

pub fn attribute_changed(&self, name: &str) -> bool

Returns true when the named attribute is currently changed.

pub fn attribute_was(&self, name: &str) -> Option<&Value>

Returns the original value for the named changed attribute.

pub fn restore_attribute(&mut self, name: &str) -> Option<Value>

Restores a single attribute by removing it from the tracked changes.

The returned value is the original value that callers should write back to the underlying attribute storage.

pub fn clear(&mut self)

Clears both current and previous change history.

pub fn apply(&mut self)

Moves current changes into previous_changes and resets the tracker.

Trait Implementations

impl Clone for ChangeTracker

fn clone(&self) -> ChangeTracker

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ChangeTracker

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ChangeTracker

fn default() -> ChangeTracker

Returns the “default value” for a type.

impl PartialEq for ChangeTracker

fn eq(&self, other: &ChangeTracker) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for ChangeTracker