Update copy indices implementation to match spec changes in w3c/IFT#252

Copy indices becomes child indices. Intersection is now based on the intersection of the child entries instead of forming a union of the child entry subset definitions.
googlefonts · Feb 5, 2025 · 63e7121 · 63e7121
1 parent ec75c7d
commit 63e7121
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Showing 9 changed files with 233 additions and 139 deletions.
diff --git a/font-codegen/src/fields.rs b/font-codegen/src/fields.rs
@@ -157,7 +157,7 @@ impl Fields {
             .find(|fld| &fld.name == name)
             .map(|fld| match &fld.typ {
                 FieldType::Scalar { typ } => typ,
-                _ => panic!("not a scalar field: {:?}", &fld.typ),
+                _ => panic!("not a scalar field"),
             })
             .or_else(|| {
                 self.read_args.as_ref().and_then(|args| {

diff --git a/font-codegen/src/parsing.rs b/font-codegen/src/parsing.rs
@@ -317,7 +317,7 @@ pub(crate) enum CountTransform {
     /// Number of bytes to hold a bitmap with max value N
     MaxValueBitmapLen,
     /// requires exactly one arg. Get the count from the $arg1.try_into::<usize>().
-    CustomCount,
+    Custom,
 }
 
 /// Attributes for specifying how to compile a field
@@ -1467,7 +1467,7 @@ static TRANSFORM_IDENTS: &[(CountTransform, &str)] = &[
     ),
     (CountTransform::BitmapLen, "bitmap_len"),
     (CountTransform::MaxValueBitmapLen, "max_value_bitmap_len"),
-    (CountTransform::CustomCount, "custom"),
+    (CountTransform::Custom, "custom"),
 ];
 
 impl FromStr for CountTransform {
@@ -1504,7 +1504,7 @@ impl CountTransform {
             CountTransform::ItemVariationDataLen => 3,
             CountTransform::BitmapLen => 1,
             CountTransform::MaxValueBitmapLen => 1,
-            CountTransform::CustomCount => 1,
+            CountTransform::Custom => 1,
         }
     }
 }
@@ -1659,7 +1659,7 @@ impl Count {
                 (CountTransform::MaxValueBitmapLen, [a]) => {
                     quote!(transforms::max_value_bitmap_len(#a))
                 }
-                (CountTransform::CustomCount, [a]) => {
+                (CountTransform::Custom, [a]) => {
                     quote!(transforms::custom_count(#a))
                 }
                 _ => unreachable!("validated before now"),

diff --git a/font-test-data/src/ift.rs b/font-test-data/src/ift.rs
@@ -296,7 +296,7 @@ pub fn features_and_design_space_format2() -> BeBuffer {
     buffer
 }
 
-pub fn copy_indices_format2() -> BeBuffer {
+pub fn child_indices_format2() -> BeBuffer {
     let mut buffer = be_buffer! {
       2u8,                      // format
 
@@ -347,33 +347,33 @@ pub fn copy_indices_format2() -> BeBuffer {
       0x0064_0000,                            // end = 100
 
       // Entry id = 5
-      {0b00000010u8: "entries[4]"},           // format = COPY_INDICES
-      1u8,                                    // copy count
-      (Uint24::new(0)),                       // copy
+      {0b00000010u8: "entries[4]"},           // format = CHILD_INDICES
+      1u8,                                    // child count
+      (Uint24::new(0)),                       // child[0] = 0
 
       // Entry id = 6
-      {0b00000010u8: "entries[5]"},           // format = COPY_INDICES
-      1u8,                                    // copy count
-      (Uint24::new(2)),                       // copy
+      {0b00000010u8: "entries[5]"},           // format = CHILD_INDICES
+      1u8,                                    // child count
+      (Uint24::new(2)),                       // child
 
       // Entry id = 7
-      {0b00000010u8: "entries[6]"},           // format = COPY_INDICES
-      4u8,                                    // copy count
-      (Uint24::new(3)),                       // copy[0]
-      (Uint24::new(2)),                       // copy[1]
-      (Uint24::new(1)),                       // copy[2]
-      (Uint24::new(0)),                       // copy[3]
+      {0b00000010u8: "entries[6]"},           // format = CHILD_INDICES
+      {4u8: "entries[6]_child_count"},        // child count
+      (Uint24::new(3)),                       // child[0] = 3
+      (Uint24::new(2)),                       // child[1] = 2
+      (Uint24::new(1)),                       // child[2] = 1
+      (Uint24::new(0)),                       // child[3] = 0
 
       // Entry id = 8
-      {0b00000010u8: "entries[7]"},           // format = COPY_INDICES
-      2u8,                                    // copy count
-      (Uint24::new(4)),                       // copy[0]
-      (Uint24::new(5)),                       // copy[1]
+      {0b00000010u8: "entries[7]"},           // format = CHILD_INDICES
+      2u8,                                    // child count
+      (Uint24::new(4)),                       // child[0] = 4
+      (Uint24::new(5)),                       // child[1] = 5
 
       // Entry id = 9
-      {0b00100010u8: "entries[8]"},           // format = CODEPOINT_BIT_2 | COPY_INDICES
-      1u8,                                    // copy count
-      (Uint24::new(0)),                       // copy[0]
+      {0b00100010u8: "entries[8]"},           // format = CODEPOINT_BIT_2 | CHILD_INDICES
+      1u8,                                    // child count
+      (Uint24::new(0)),                       // chil[0] = 0
       100u16,                                 // bias
       [0b00001101, 0b00000011, 0b00110001u8]  // codepoints = [100..117]
     };

diff --git a/incremental-font-transfer/src/patch_group.rs b/incremental-font-transfer/src/patch_group.rs
@@ -1446,7 +1446,7 @@ mod tests {
         let s = SubsetDefinition::codepoints([5].into_iter().collect());
         let g = PatchGroup::select_next_patches(font.clone(), &s);
 
-        assert!(g.is_err());
+        assert!(g.is_err(), "did not fail as expected.");
         if let Err(err) = g {
             assert_eq!(ReadError::ValidationError, err);
         }