Fix first/last_index_of functions to use deep object comparison (#612)

stellar · Dec 15, 2022 · 94a347c · 94a347c
1 parent 995386a
commit 94a347c
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Showing 2 changed files with 24 additions and 6 deletions.
diff --git a/soroban-env-host/src/host.rs b/soroban-env-host/src/host.rs
@@ -1649,7 +1649,7 @@ impl VmCallerCheckedEnv for Host {
     ) -> Result<RawVal, Self::Error> {
         self.visit_obj(v, |hv: &HostVec| {
             Ok(
-                match hv.first_index_of(|other| x.shallow_eq(other), &self.as_budget())? {
+                match hv.first_index_of(|other| self.compare(&x, other), &self.as_budget())? {
                     Some(u) => self.usize_to_rawval_u32(u)?,
                     None => RawVal::from_void(),
                 },
@@ -1665,7 +1665,7 @@ impl VmCallerCheckedEnv for Host {
     ) -> Result<RawVal, Self::Error> {
         self.visit_obj(v, |hv: &HostVec| {
             Ok(
-                match hv.last_index_of(|other| x.shallow_eq(other), self.as_budget())? {
+                match hv.last_index_of(|other| self.compare(&x, other), self.as_budget())? {
                     Some(u) => self.usize_to_rawval_u32(u)?,
                     None => RawVal::from_void(),
                 },

diff --git a/soroban-env-host/src/host/metered_vector.rs b/soroban-env-host/src/host/metered_vector.rs
@@ -201,18 +201,36 @@ where
 
     pub fn first_index_of<F>(&self, f: F, budget: &Budget) -> Result<Option<usize>, HostError>
     where
-        F: FnMut(&A) -> bool,
+        F: Fn(&A) -> Result<Ordering, HostError>,
     {
         self.charge_scan(budget)?;
-        Ok(self.vec.iter().position(f))
+        let mut i = 0;
+        let mut iter = self.vec.iter();
+        // this is similar logic to `iter.position(f)` but is fallible
+        while let Some(val) = iter.next() {
+            if f(val)? == Ordering::Equal {
+                return Ok(Some(i));
+            }
+            i += 1;
+        }
+        Ok(None)
     }
 
     pub fn last_index_of<F>(&self, f: F, budget: &Budget) -> Result<Option<usize>, HostError>
     where
-        F: FnMut(&A) -> bool,
+        F: Fn(&A) -> Result<Ordering, HostError>,
     {
         self.charge_scan(budget)?;
-        Ok(self.vec.iter().rposition(f))
+        let mut i = self.vec.len();
+        let mut iter = self.vec.iter();
+        // this is similar logic to `iter.rposition(f)` but is fallible
+        while let Some(val) = iter.next_back() {
+            i -= 1;
+            if f(val)? == Ordering::Equal {
+                return Ok(Some(i));
+            }
+        }
+        Ok(None)
     }
 
     pub fn binary_search_by<F>(