✨ Improve paths deserialization (wasm) (#6501)

* ♻️ Refactor path wasm code to its own wasm submodule

* ♻️ Use unified enum for RawSegmentData and transmute to deserialize

* ♻️ Move set_shape_path_attrs to wasm::paths module

* 💄 Unify repr declarations

render-wasm/src/main.rs

@@ -345,38 +345,6 @@ pub extern "C" fn set_shape_blur(blur_type: u8, hidden: bool, value: f32) {
     });
 }
 
-#[no_mangle]
-pub extern "C" fn set_shape_path_content() {
-    with_current_shape!(state, |shape: &mut Shape| {
-        let bytes = mem::bytes();
-        let raw_segments = bytes
-            .chunks(size_of::<shapes::RawPathData>())
-            .map(|data| shapes::RawPathData {
-                data: data.try_into().unwrap(),
-            })
-            .collect();
-        shape.set_path_segments(raw_segments).unwrap();
-    });
-}
-
-// Extracts a string from the bytes slice until the next null byte (0) and returns the result as a `String`.
-// Updates the `start` index to the end of the extracted string.
-fn extract_string(start: &mut usize, bytes: &[u8]) -> String {
-    match bytes[*start..].iter().position(|&b| b == 0) {
-        Some(pos) => {
-            let end = *start + pos;
-            let slice = &bytes[*start..end];
-            *start = end + 1; // Move the `start` pointer past the null byte
-                              // Call to unsafe function within an unsafe block
-            unsafe { String::from_utf8_unchecked(slice.to_vec()) }
-        }
-        None => {
-            *start = bytes.len(); // Move `start` to the end if no null byte is found
-            String::new()
-        }
-    }
-}
-
 #[no_mangle]
 pub extern "C" fn set_shape_corners(r1: f32, r2: f32, r3: f32, r4: f32) {
     with_current_shape!(state, |shape: &mut Shape| {
@@ -384,19 +352,6 @@ pub extern "C" fn set_shape_corners(r1: f32, r2: f32, r3: f32, r4: f32) {
     });
 }
 
-#[no_mangle]
-pub extern "C" fn set_shape_path_attrs(num_attrs: u32) {
-    with_current_shape!(state, |shape: &mut Shape| {
-        let bytes = mem::bytes();
-        let mut start = 0;
-        for _ in 0..num_attrs {
-            let name = extract_string(&mut start, &bytes);
-            let value = extract_string(&mut start, &bytes);
-            shape.set_path_attr(name, value);
-        }
-    });
-}
-
 #[no_mangle]
 pub extern "C" fn propagate_modifiers(pixel_precision: bool) -> *mut u8 {
     let bytes = mem::bytes();

render-wasm/src/shapes.rs

@@ -469,8 +469,8 @@ impl Shape {
         self.strokes.clear();
     }
 
-    pub fn set_path_segments(&mut self, buffer: Vec<RawPathData>) -> Result<(), String> {
-        let path = Path::try_from(buffer)?;
+    pub fn set_path_segments(&mut self, segments: Vec<Segment>) {
+        let path = Path::new(segments);
 
         match &mut self.shape_type {
             Type::Bool(Bool { bool_type, .. }) => {
@@ -484,7 +484,6 @@ impl Shape {
             }
             _ => {}
         };
-        Ok(())
     }
 
     pub fn set_path_attr(&mut self, name: String, value: String) {

render-wasm/src/shapes/paths.rs

@@ -1,74 +1,15 @@
 use skia_safe::{self as skia, Matrix};
-use std::array::TryFromSliceError;
 
 type Point = (f32, f32);
 
-fn stringify_slice_err(_: TryFromSliceError) -> String {
-    "Error deserializing path".to_string()
-}
-
-#[derive(Debug)]
-pub struct RawPathData {
-    pub data: [u8; 28],
-}
-
-impl RawPathData {
-    fn command(&self) -> Result<u16, String> {
-        let cmd = u16::from_le_bytes(self.data[0..2].try_into().map_err(stringify_slice_err)?);
-        Ok(cmd)
-    }
-
-    fn xy(&self) -> Result<Point, String> {
-        let x = f32::from_le_bytes(self.data[20..24].try_into().map_err(stringify_slice_err)?);
-        let y = f32::from_le_bytes(self.data[24..].try_into().map_err(stringify_slice_err)?);
-        Ok((x, y))
-    }
-
-    fn c1(&self) -> Result<Point, String> {
-        let c1_x = f32::from_le_bytes(self.data[4..8].try_into().map_err(stringify_slice_err)?);
-        let c1_y = f32::from_le_bytes(self.data[8..12].try_into().map_err(stringify_slice_err)?);
-
-        Ok((c1_x, c1_y))
-    }
-
-    fn c2(&self) -> Result<Point, String> {
-        let c2_x = f32::from_le_bytes(self.data[12..16].try_into().map_err(stringify_slice_err)?);
-        let c2_y = f32::from_le_bytes(self.data[16..20].try_into().map_err(stringify_slice_err)?);
-
-        Ok((c2_x, c2_y))
-    }
-}
-
-const MOVE_TO: u16 = 1;
-const LINE_TO: u16 = 2;
-const CURVE_TO: u16 = 3;
-const CLOSE: u16 = 4;
-
 #[derive(Debug, PartialEq, Copy, Clone)]
-enum Segment {
+pub enum Segment {
     MoveTo(Point),
     LineTo(Point),
     CurveTo((Point, Point, Point)),
     Close,
 }
 
-impl TryFrom<RawPathData> for Segment {
-    type Error = String;
-    fn try_from(value: RawPathData) -> Result<Self, Self::Error> {
-        let cmd = value.command()?;
-        match cmd {
-            MOVE_TO => Ok(Segment::MoveTo(value.xy()?)),
-            LINE_TO => Ok(Segment::LineTo(value.xy()?)),
-            CURVE_TO => Ok(Segment::CurveTo((value.c1()?, value.c2()?, value.xy()?))),
-            CLOSE => Ok(Segment::Close),
-            _ => Err(format!(
-                "Error deserializing path. Unknown command/flags: {:#010x}",
-                cmd
-            )),
-        }
-    }
-}
-
 #[derive(Debug, Clone, PartialEq)]
 pub struct Path {
     segments: Vec<Segment>,
@@ -78,20 +19,13 @@ pub struct Path {
 
 impl Default for Path {
     fn default() -> Self {
-        Path::try_from(Vec::new()).unwrap()
+        Self::new(vec![])
     }
 }
 
-impl TryFrom<Vec<RawPathData>> for Path {
-    type Error = String;
-
-    fn try_from(value: Vec<RawPathData>) -> Result<Self, Self::Error> {
+impl Path {
+    pub fn new(segments: Vec<Segment>) -> Self {
         let mut open = true;
-        let segments = value
-            .into_iter()
-            .map(Segment::try_from)
-            .collect::<Result<Vec<Segment>, String>>()?;
-
         let mut skia_path = skia::Path::new();
         let mut start = None;
 
@@ -123,15 +57,14 @@ impl TryFrom<Vec<RawPathData>> for Path {
                 }
             }
         }
-        Ok(Path {
+
+        Self {
             segments,
             skia_path,
             open,
-        })
+        }
     }
-}
 
-impl Path {
     pub fn to_skia_path(&self) -> skia::Path {
         self.skia_path.snapshot()
     }

render-wasm/src/wasm.rs

@@ -1,4 +1,5 @@
 pub mod fills;
 pub mod fonts;
+pub mod paths;
 pub mod strokes;
 pub mod text;

render-wasm/src/wasm/fills.rs

@@ -9,9 +9,7 @@ use crate::STATE;
 
 const RAW_FILL_DATA_SIZE: usize = std::mem::size_of::<RawFillData>();
 
-#[repr(C)]
-#[repr(align(4))]
-#[repr(u8)]
+#[repr(C, u8, align(4))]
 #[derive(Debug, PartialEq, Clone, Copy)]
 #[allow(dead_code)]
 pub enum RawFillData {

render-wasm/src/wasm/paths.rs

@@ -0,0 +1,186 @@
+use crate::shapes::{Path, Segment};
+use crate::{mem, with_current_shape, STATE};
+
+const RAW_SEGMENT_DATA_SIZE: usize = size_of::<RawSegmentData>();
+
+#[repr(C, u16, align(4))]
+#[derive(Debug, PartialEq, Clone, Copy)]
+#[allow(dead_code)]
+enum RawSegmentData {
+    MoveTo(RawMoveCommand) = 0x01,
+    LineTo(RawLineCommand) = 0x02,
+    CurveTo(RawCurveCommand) = 0x03,
+    Close = 0x04,
+}
+
+impl From<[u8; size_of::<RawSegmentData>()]> for RawSegmentData {
+    fn from(bytes: [u8; size_of::<RawSegmentData>()]) -> Self {
+        unsafe { std::mem::transmute(bytes) }
+    }
+}
+
+impl TryFrom<&[u8]> for RawSegmentData {
+    type Error = String;
+    fn try_from(bytes: &[u8]) -> Result<Self, Self::Error> {
+        let data: [u8; RAW_SEGMENT_DATA_SIZE] = bytes
+            .get(0..RAW_SEGMENT_DATA_SIZE)
+            .and_then(|slice| slice.try_into().ok())
+            .ok_or("Invalid path data".to_string())?;
+        Ok(RawSegmentData::from(data))
+    }
+}
+
+#[repr(C, align(4))]
+#[derive(Debug, PartialEq, Clone, Copy)]
+struct RawMoveCommand {
+    _padding: [u32; 4],
+    x: f32,
+    y: f32,
+}
+
+#[repr(C, align(4))]
+#[derive(Debug, PartialEq, Clone, Copy)]
+struct RawLineCommand {
+    _padding: [u32; 4],
+    x: f32,
+    y: f32,
+}
+
+#[repr(C, align(4))]
+#[derive(Debug, PartialEq, Clone, Copy)]
+struct RawCurveCommand {
+    c1_x: f32,
+    c1_y: f32,
+    c2_x: f32,
+    c2_y: f32,
+    x: f32,
+    y: f32,
+}
+
+impl From<RawSegmentData> for Segment {
+    fn from(value: RawSegmentData) -> Self {
+        match value {
+            RawSegmentData::MoveTo(cmd) => Segment::MoveTo((cmd.x, cmd.y)),
+            RawSegmentData::LineTo(cmd) => Segment::LineTo((cmd.x, cmd.y)),
+            RawSegmentData::CurveTo(cmd) => {
+                Segment::CurveTo(((cmd.c1_x, cmd.c1_y), (cmd.c2_x, cmd.c2_y), (cmd.x, cmd.y)))
+            }
+            RawSegmentData::Close => Segment::Close,
+        }
+    }
+}
+
+impl From<Vec<RawSegmentData>> for Path {
+    fn from(value: Vec<RawSegmentData>) -> Self {
+        let segments = value.into_iter().map(Segment::from).collect();
+        Path::new(segments)
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn set_shape_path_content() {
+    with_current_shape!(state, |shape: &mut Shape| {
+        let bytes = mem::bytes();
+
+        let segments = bytes
+            .chunks(size_of::<RawSegmentData>())
+            .map(|chunk| RawSegmentData::try_from(chunk).expect("Invalid path data"))
+            .map(Segment::from)
+            .collect();
+
+        shape.set_path_segments(segments);
+    });
+}
+
+// Extracts a string from the bytes slice until the next null byte (0) and returns the result as a `String`.
+// Updates the `start` index to the end of the extracted string.
+fn extract_string(start: &mut usize, bytes: &[u8]) -> String {
+    match bytes[*start..].iter().position(|&b| b == 0) {
+        Some(pos) => {
+            let end = *start + pos;
+            let slice = &bytes[*start..end];
+            *start = end + 1; // Move the `start` pointer past the null byte
+                              // Call to unsafe function within an unsafe block
+            unsafe { String::from_utf8_unchecked(slice.to_vec()) }
+        }
+        None => {
+            *start = bytes.len(); // Move `start` to the end if no null byte is found
+            String::new()
+        }
+    }
+}
+
+#[no_mangle]
+pub extern "C" fn set_shape_path_attrs(num_attrs: u32) {
+    with_current_shape!(state, |shape: &mut Shape| {
+        let bytes = mem::bytes();
+        let mut start = 0;
+        for _ in 0..num_attrs {
+            let name = extract_string(&mut start, &bytes);
+            let value = extract_string(&mut start, &bytes);
+            shape.set_path_attr(name, value);
+        }
+    });
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_move_command_deserialization() {
+        let mut bytes = [0x00; size_of::<RawSegmentData>()];
+        bytes[0..2].copy_from_slice(&0x01_u16.to_le_bytes());
+        bytes[20..24].copy_from_slice(&1.0_f32.to_le_bytes());
+        bytes[24..28].copy_from_slice(&2.0_f32.to_le_bytes());
+
+        let raw_segment = RawSegmentData::try_from(&bytes[..]).unwrap();
+        let segment = Segment::from(raw_segment);
+
+        assert_eq!(segment, Segment::MoveTo((1.0, 2.0)));
+    }
+
+    #[test]
+    fn test_line_command_deserialization() {
+        let mut bytes = [0x00; size_of::<RawSegmentData>()];
+        bytes[0..2].copy_from_slice(&0x02_u16.to_le_bytes());
+        bytes[20..24].copy_from_slice(&3.0_f32.to_le_bytes());
+        bytes[24..28].copy_from_slice(&4.0_f32.to_le_bytes());
+
+        let raw_segment = RawSegmentData::try_from(&bytes[..]).unwrap();
+        let segment = Segment::from(raw_segment);
+
+        assert_eq!(segment, Segment::LineTo((3.0, 4.0)));
+    }
+
+    #[test]
+    fn test_curve_command_deserialization() {
+        let mut bytes = [0x00; size_of::<RawSegmentData>()];
+        bytes[0..2].copy_from_slice(&0x03_u16.to_le_bytes());
+        bytes[4..8].copy_from_slice(&1.0_f32.to_le_bytes());
+        bytes[8..12].copy_from_slice(&2.0_f32.to_le_bytes());
+        bytes[12..16].copy_from_slice(&3.0_f32.to_le_bytes());
+        bytes[16..20].copy_from_slice(&4.0_f32.to_le_bytes());
+        bytes[20..24].copy_from_slice(&5.0_f32.to_le_bytes());
+        bytes[24..28].copy_from_slice(&6.0_f32.to_le_bytes());
+
+        let raw_segment = RawSegmentData::try_from(&bytes[..]).unwrap();
+        let segment = Segment::from(raw_segment);
+
+        assert_eq!(
+            segment,
+            Segment::CurveTo(((1.0, 2.0), (3.0, 4.0), (5.0, 6.0)))
+        );
+    }
+
+    #[test]
+    fn test_close_command_deserialization() {
+        let mut bytes = [0x00; size_of::<RawSegmentData>()];
+        bytes[0..2].copy_from_slice(&0x04_u16.to_le_bytes());
+
+        let raw_segment = RawSegmentData::try_from(&bytes[..]).unwrap();
+        let segment = Segment::from(raw_segment);
+
+        assert_eq!(segment, Segment::Close);
+    }
+}