oh RFC 6902, why, why

idubrov · Mar 19, 2024 · bab30d8 · bab30d8
1 parent b9ee0f0
commit bab30d8
Showing 1 changed file with 13 additions and 6 deletions.
diff --git a/src/diff.rs b/src/diff.rs
@@ -4,27 +4,30 @@ use serde_json::Value;
 struct PatchDiffer {
     path: Pointer,
     patch: super::Patch,
+    shift: usize,
 }
 
 impl PatchDiffer {
     fn new() -> Self {
         Self {
             path: Pointer::root(),
             patch: super::Patch(Vec::new()),
+            shift: 0,
         }
     }
 }
 
 impl<'a> treediff::Delegate<'a, treediff::value::Key, Value> for PatchDiffer {
     fn push(&mut self, key: &treediff::value::Key) {
         match key {
-            treediff::value::Key::Index(idx) => self.path.push_back(idx.into()),
+            treediff::value::Key::Index(idx) => self.path.push_back((idx - self.shift).into()),
             treediff::value::Key::String(key) => self.path.push_back(key.into()),
         }
     }
 
     fn pop(&mut self) {
         self.path.pop_back();
+        self.shift = 0;
     }
 
     fn removed<'b>(&mut self, k: &'b treediff::value::Key, _v: &'a Value) {
@@ -34,7 +37,11 @@ impl<'a> treediff::Delegate<'a, treediff::value::Key, Value> for PatchDiffer {
             .push(super::PatchOperation::Remove(super::RemoveOperation {
                 path: self.path.clone(),
             }));
-        self.pop();
+        // Shift indices, we are deleting array elements
+        if let treediff::value::Key::Index(_) = k {
+            self.shift += 1;
+        }
+        self.path.pop_back();
     }
 
     fn added(&mut self, k: &treediff::value::Key, v: &Value) {
@@ -45,7 +52,7 @@ impl<'a> treediff::Delegate<'a, treediff::value::Key, Value> for PatchDiffer {
                 path: self.path.clone(),
                 value: v.clone(),
             }));
-        self.pop();
+        self.path.pop_back();
     }
 
     fn modified(&mut self, _old: &'a Value, new: &'a Value) {
@@ -167,7 +174,7 @@ mod tests {
             p,
             serde_json::from_value(json!([
                 { "op": "remove", "path": "/0" },
-                { "op": "remove", "path": "/1" },
+                { "op": "remove", "path": "/0" },
             ]))
             .unwrap()
         );
@@ -182,7 +189,7 @@ mod tests {
             p,
             serde_json::from_value(json!([
                 { "op": "remove", "path": "/1" },
-                { "op": "remove", "path": "/2" },
+                { "op": "remove", "path": "/1" },
             ]))
             .unwrap()
         );
@@ -197,7 +204,7 @@ mod tests {
             serde_json::from_value(json!([
                 { "op": "add", "path": "/hello", "value": "bye" },
                 { "op": "remove", "path": "/0" },
-                { "op": "remove", "path": "/1" },
+                { "op": "remove", "path": "/0" },
             ]))
             .unwrap()
         );