Merge pull request #86 from ivanceras/pre_eval-clone

This adds prediff feature for sauron. This is the first step towards optimization of skipping nodes for diffing by checking the App fields alone.

Cargo.toml

@@ -26,6 +26,7 @@ with-ric = ["sauron-core/with-ric"]
 with-raf = ["sauron-core/with-raf"]
 with-interning = ["sauron-core/with-interning"]
 with-jss = ["sauron-macro", "with-lookup"] #enable use of jss (css style in json format)
+prediff = ["sauron-core/prediff"]
 
 # shows telemetry such as duration it took to update the dom
 with-measure = ["sauron-core/with-measure"]

TODO.md

@@ -234,7 +234,8 @@
 - [ ] Bring back CreatedNode maybe with a different name: `DomNode` which wraps the `Node` or `Element` along with it's closures from event listener
     - These are then saved into the `Program` where when removed or dropped, it will also drop the associated closures with them, thereby simplifying the code.
     - Right now, we are attaching a `vdom-data` attribute for nodes that have listeners
-
+- [ ] Make use of `Arc<RwLock>` to check if can solve copying the `APP` via `transmute_copy`. ~~it didn't solve it~~
+    - See if there are performance penalty
 
 ## Features
 - [X] Storage service (May not be needed since the user can directly use web-sys)
@@ -304,6 +305,9 @@
 - [ ] Find a way to break up building the view into multiple frames, since view can take a long time to build
 - [ ] Find a way to break up diffing the current vdom and the new vdom as they can also take a bit of long time as well.
 - [ ] Add benchmark function for using CACHE_ELEMENT and not
+- [ ] Make dispatch pending patches break when the animation frame timeouts, same way as dispatching pending msgs
+- [ ] Check the last time the dom is updated, if it is less than 17ms, delay the dom update until 17ms has elapsed since the last update.
+- [ ] Make use of [talc](https://github.com/SFBdragon/talc) allocator for faster and leaner memory
 
 ## Maintenance
 - [X] Move `sauron-markdown` into it's own repo, for keeping sauron slim.

crates/sauron-core/Cargo.toml

@@ -20,7 +20,7 @@ log = "0.4"
 cfg-if = "1.0"
 thiserror = "1.0"
 doc-comment = "0.3"
-mt-dom = { version = "0.59.1" }
+mt-dom = { version = "0.59.2" }
 #mt-dom = { path = "../../../mt-dom" }
 #mt-dom = { git = "https://github.com/ivanceras/mt-dom", branch = "master" }
 once_cell = "1.8"
@@ -117,6 +117,7 @@ with-ric = [] # use of request_idle_callback in javascript
 with-raf = [] # use of request_animation_frame in javascript
 with-interning = [] # use caching of strings when crossing rust to js, for faster transfer
 custom_element = [] # use of register_custom_element, adding this will add the js snippets
+prediff = [] # diffing optimization
 
 [dev-dependencies]
 wasm-bindgen-test = "0.3"

crates/sauron-core/src/dom.rs

@@ -16,7 +16,7 @@ mod task;
 use cfg_if::cfg_if;
 
 cfg_if! {if #[cfg(feature = "with-dom")] {
-    pub use application::{Application, Measurements};
+    pub use application::{Application, Measurements, PreDiff, diff_if};
     #[cfg(feature = "custom_element")]
     pub use web_component::{register_web_component, WebComponent, WebComponentWrapper};
     pub use dom_patch::{DomPatch, PatchVariant};

crates/sauron-core/src/dom/application.rs

@@ -1,29 +1,36 @@
 use crate::dom::Cmd;
 use crate::vdom::Node;
+pub use prediff::{diff_if, PreDiff};
+
+mod prediff;
+
 
 /// An Application is the root component of your program.
 /// Everything that happens in your application is done here.
 ///
-pub trait Application<MSG>
+pub trait Application<MSG> : Sized + 'static
 where
     MSG: 'static,
 {
     ///  The application can implement this method where it can modify its initial state.
     ///  This method is called right after the program is mounted into the DOM.
-    fn init(&mut self) -> Cmd<Self, MSG>
-    where
-        Self: Sized + 'static,
-    {
+    fn init(&mut self) -> Cmd<Self, MSG> {
         Cmd::none()
     }
 
     /// Update the component with a message.
     /// The update function returns a Cmd, which can be executed by the runtime.
     ///
     /// Called each time an action is triggered from the view
-    fn update(&mut self, _msg: MSG) -> Cmd<Self, MSG>
-    where
-        Self: Sized + 'static;
+    fn update(&mut self, _msg: MSG) -> Cmd<Self, MSG>;
+
+    /// an optimization solution.
+    /// pre evaluate the expression to determine
+    /// whether to diff the nodes
+    #[cfg(feature = "prediff")]
+    fn prediff(&self, _other: &Self) -> Option<Vec<PreDiff>> {
+        None
+    }
 
     /// Returns a node on how the component is presented.
     fn view(&self) -> Node<MSG>;
@@ -43,8 +50,6 @@ where
     ///
     /// Warning: DO NOT use for anything else other than the intended purpose
     fn measurements(&self, measurements: Measurements) -> Cmd<Self, MSG>
-    where
-        Self: Sized + 'static,
     {
         log::debug!("Measurements: {:#?}", measurements);
         Cmd::none().no_render()

crates/sauron-core/src/dom/application/prediff.rs

@@ -0,0 +1,73 @@
+use mt_dom::TreePath;
+use std::fmt;
+
+///
+pub struct PreDiff {
+    expr: Box<dyn Fn() -> bool>,
+    children: Vec<PreDiff>,
+}
+
+impl fmt::Debug for PreDiff {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "({}", (self.expr)())?;
+        write!(f, ",[")?;
+        for child in &self.children {
+            child.fmt(f)?;
+        }
+        write!(f, "])")?;
+        Ok(())
+    }
+}
+
+impl PreDiff {
+    /// new
+    pub fn new(val: bool, children: impl IntoIterator<Item = Self>) -> Self {
+        Self {
+            expr: Box::new(move || val),
+            children: children.into_iter().collect(),
+        }
+    }
+
+    ///
+    pub fn none() -> Self {
+        PreDiff {
+            expr: Box::new(|| false),
+            children: vec![],
+        }
+    }
+
+    ///
+    pub fn traverse(evals: &[PreDiff]) -> Vec<TreePath> {
+        let root = TreePath::root();
+        if evals.len() == 1 {
+            Self::traverse_recursive(&evals[0], root)
+        } else {
+            Self::traverse_list(evals, root)
+        }
+    }
+
+    ///
+    fn traverse_list(evals: &[PreDiff], current: TreePath) -> Vec<TreePath> {
+        let mut paths = vec![];
+        for (i, eval) in evals.iter().enumerate() {
+            let more_paths = eval.traverse_recursive(current.traverse(i));
+            paths.extend(more_paths);
+        }
+        paths
+    }
+
+    fn traverse_recursive(&self, current: TreePath) -> Vec<TreePath> {
+        let mut paths = vec![];
+        if (self.expr)() {
+            paths.push(current.clone());
+        }
+        let more_paths = Self::traverse_list(&self.children, current);
+        paths.extend(more_paths);
+        paths
+    }
+}
+
+/// evaluate check
+pub fn diff_if(val: bool, children: impl IntoIterator<Item = PreDiff>) -> PreDiff {
+    PreDiff::new(val, children)
+}

crates/sauron-core/src/dom/cmd.rs

@@ -24,7 +24,7 @@ where
 impl<APP, MSG> Cmd<APP, MSG>
 where
     MSG: 'static,
-    APP: Application<MSG> + 'static,
+    APP: Application<MSG>,
 {
     /// creates a new Cmd from a function
     pub fn new<F>(f: F) -> Self
@@ -118,7 +118,7 @@ where
 impl<APP, MSG> From<Effects<MSG, ()>> for Cmd<APP, MSG>
 where
     MSG: 'static,
-    APP: Application<MSG> + 'static,
+    APP: Application<MSG>,
 {
     /// Convert Effects that has only follow ups
     fn from(effects: Effects<MSG, ()>) -> Self {
@@ -139,7 +139,7 @@ where
 impl<APP, MSG, IN> From<IN> for Cmd<APP, MSG>
 where
     MSG: 'static,
-    APP: Application<MSG> + 'static,
+    APP: Application<MSG>,
     IN: IntoIterator<Item = Effects<MSG, ()>>,
 {
     fn from(effects: IN) -> Self {
@@ -150,7 +150,7 @@ where
 impl<APP, MSG> From<Task<MSG>> for Cmd<APP, MSG>
 where
     MSG: 'static,
-    APP: Application<MSG> + 'static,
+    APP: Application<MSG>,
 {
     fn from(task: Task<MSG>) -> Self {
         let task = task.task;

crates/sauron-core/src/dom/dom_node.rs

@@ -81,7 +81,7 @@ fn create_unique_identifier() -> usize {
 impl<APP, MSG> Program<APP, MSG>
 where
     MSG: 'static,
-    APP: Application<MSG> + 'static,
+    APP: Application<MSG>,
 {
     /// create a text node
     pub fn create_text_node(txt: &str) -> Text {