Populate layer entry cache (#437)

* Populate layer entry cache

* Serialize the DocumentMessageHandler

* Fix restoring of collapsed/expanded state, add iter impl for Layer, and clean up layer_data() functions

* Fixed bug with CreateEmptyLayer revealed by test

Co-authored-by: Keavon Chambers <keavon@keavon.com>
Co-authored-by: otdavies <oliver@psyfer.io>

graphene/src/document.rs

@@ -34,10 +34,6 @@ impl Default for Document {
 }
 
 impl Document {
-	pub fn with_content(serialized_content: &str) -> Result<Self, DocumentError> {
-		serde_json::from_str(serialized_content).map_err(|e| DocumentError::InvalidFile(e.to_string()))
-	}
-
 	/// Wrapper around render, that returns the whole document as a Response.
 	pub fn render_root(&mut self, mode: ViewMode) -> String {
 		self.root.render(&mut vec![], mode);
@@ -48,12 +44,6 @@ impl Document {
 		self.state_identifier.finish()
 	}
 
-	pub fn serialize_document(&self) -> String {
-		let val = serde_json::to_string(self);
-		// We fully expect the serialization to succeed
-		val.unwrap()
-	}
-
 	/// Checks whether each layer under `path` intersects with the provided `quad` and adds all intersection layers as paths to `intersections`.
 	pub fn intersects_quad(&self, quad: Quad, path: &mut Vec<LayerId>, intersections: &mut Vec<Vec<LayerId>>) {
 		self.layer(path).unwrap().intersects_quad(quad, path, intersections);

graphene/src/layers/mod.rs

@@ -105,6 +105,10 @@ impl Layer {
 		}
 	}
 
+	pub fn iter(&self) -> LayerIter<'_> {
+		LayerIter { stack: vec![self] }
+	}
+
 	pub fn render(&mut self, transforms: &mut Vec<DAffine2>, view_mode: ViewMode) -> &str {
 		if !self.visible {
 			return "";
@@ -179,3 +183,40 @@ impl Clone for Layer {
 		}
 	}
 }
+
+impl<'a> IntoIterator for &'a Layer {
+	type Item = &'a Layer;
+	type IntoIter = LayerIter<'a>;
+
+	fn into_iter(self) -> Self::IntoIter {
+		self.iter()
+	}
+}
+
+#[derive(Debug)]
+pub struct LayerIter<'a> {
+	pub stack: Vec<&'a Layer>,
+}
+
+impl Default for LayerIter<'_> {
+	fn default() -> Self {
+		Self { stack: vec![] }
+	}
+}
+
+impl<'a> Iterator for LayerIter<'a> {
+	type Item = &'a Layer;
+
+	fn next(&mut self) -> Option<Self::Item> {
+		match self.stack.pop() {
+			Some(layer) => {
+				if let LayerDataType::Folder(folder) = &layer.data {
+					let layers = folder.layers();
+					self.stack.extend(layers);
+				};
+				Some(layer)
+			}
+			None => None,
+		}
+	}
+}