Add FullHistory

patican/src/canvas.rs

@@ -1,50 +1,11 @@
 use crate::{
     color::{Color, Rgba},
     command::{Command, Metadata, PutCommand, RemoveCommand},
+    history::History,
     spatial::{Point, RectangularArea},
 };
 use std::collections::BTreeMap;
 
-pub trait History {
-    fn len(&self) -> usize;
-    fn is_empty(&self) -> bool {
-        self.len() == 0
-    }
-
-    fn append_command(&mut self, command: Command);
-    fn get_redo_command(&self, index: usize) -> Option<&Command>;
-    fn get_undo_command(&self, index: usize) -> Option<&Command>;
-}
-
-// TODO: PerfectHistory or FullHistory
-
-#[derive(Debug, Default, Clone)]
-pub struct NoopHistory {
-    len: usize,
-}
-
-impl NoopHistory {
-    pub fn new() -> Self {
-        Self::default()
-    }
-}
-
-impl History for NoopHistory {
-    fn append_command(&mut self, _command: Command) {}
-
-    fn len(&self) -> usize {
-        self.len
-    }
-
-    fn get_redo_command(&self, _index: usize) -> Option<&Command> {
-        None
-    }
-
-    fn get_undo_command(&self, _index: usize) -> Option<&Command> {
-        None
-    }
-}
-
 #[derive(Debug, Clone)]
 pub struct Canvas<H> {
     cursor: Point,

patican/src/history.rs

@@ -0,0 +1,115 @@
+use std::collections::VecDeque;
+
+use crate::command::Command;
+
+pub trait History {
+    fn len(&self) -> usize;
+    fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
+    fn append_command(&mut self, command: Command);
+    fn get_redo_command(&self, index: usize) -> Option<&Command>;
+    fn get_undo_command(&self, index: usize) -> Option<&Command>;
+}
+
+#[derive(Debug, Default, Clone)]
+pub struct NullHistory {
+    len: usize,
+}
+
+impl NullHistory {
+    pub fn new() -> Self {
+        Self::default()
+    }
+}
+
+impl History for NullHistory {
+    fn append_command(&mut self, _command: Command) {}
+
+    fn len(&self) -> usize {
+        self.len
+    }
+
+    fn get_redo_command(&self, _index: usize) -> Option<&Command> {
+        None
+    }
+
+    fn get_undo_command(&self, _index: usize) -> Option<&Command> {
+        None
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct FullHistory(LimitedHistory);
+
+impl FullHistory {
+    pub fn new() -> Self {
+        Self(LimitedHistory::new(usize::MAX))
+    }
+}
+
+impl Default for FullHistory {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl History for FullHistory {
+    fn append_command(&mut self, command: Command) {
+        self.0.append_command(command);
+    }
+
+    fn len(&self) -> usize {
+        self.0.len()
+    }
+
+    fn get_redo_command(&self, index: usize) -> Option<&Command> {
+        self.0.get_redo_command(index)
+    }
+
+    fn get_undo_command(&self, index: usize) -> Option<&Command> {
+        self.0.get_undo_command(index)
+    }
+}
+
+#[derive(Debug, Default, Clone)]
+pub struct LimitedHistory {
+    limit: usize,
+    len: usize,
+    commands: VecDeque<Command>,
+}
+
+impl LimitedHistory {
+    pub fn new(limit: usize) -> Self {
+        Self {
+            limit,
+            len: 0,
+            commands: VecDeque::new(),
+        }
+    }
+}
+
+impl History for LimitedHistory {
+    fn len(&self) -> usize {
+        self.len
+    }
+
+    fn append_command(&mut self, command: Command) {
+        self.len += 1;
+        self.commands.push_back(command);
+        if self.commands.len() > self.limit {
+            self.commands.pop_front();
+        }
+    }
+
+    fn get_redo_command(&self, index: usize) -> Option<&Command> {
+        let dropepd = self.len - self.commands.len();
+        let i = index.checked_sub(dropepd)?;
+        self.commands.get(i)
+    }
+
+    fn get_undo_command(&self, index: usize) -> Option<&Command> {
+        todo!()
+    }
+}

patican/src/lib.rs

@@ -1,4 +1,5 @@
 pub mod canvas;
 pub mod color;
 pub mod command;
+pub mod history;
 pub mod spatial;