From d12592d50d3aeb494d2e5ddabf4951794086d8c8 Mon Sep 17 00:00:00 2001
From: James <james@prestwi.ch>
Date: Mon, 25 Aug 2025 15:04:21 -0400
Subject: [PATCH 1/2] feat: trait for inspectors that accumulate output

---
 src/inspectors/mod.rs         |  3 +++
 src/inspectors/with_output.rs | 49 +++++++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+)
 create mode 100644 src/inspectors/with_output.rs

diff --git a/src/inspectors/mod.rs b/src/inspectors/mod.rs
index 9e414f6..fbf7df5 100644
--- a/src/inspectors/mod.rs
+++ b/src/inspectors/mod.rs
@@ -10,6 +10,9 @@ pub use set::InspectorSet;
 mod spanning;
 pub use spanning::SpanningInspector;
 
+mod with_output;
+pub use with_output::InspectorWithOutput;
+
 #[cfg(test)]
 mod test {
     use super::*;
diff --git a/src/inspectors/with_output.rs b/src/inspectors/with_output.rs
new file mode 100644
index 0000000..3d901c1
--- /dev/null
+++ b/src/inspectors/with_output.rs
@@ -0,0 +1,49 @@
+use crate::{helpers::Ctx, Trevm};
+use revm::{inspector::CountInspector, Database};
+
+/// An inspector that can produce an output value after EVM execution.
+pub trait InspectorWithOutput<CTX>: revm::inspector::Inspector<CTX> {
+    /// The type of output produced by the inspector.
+    type Output;
+
+    /// Returns `true` if the inspector has a valid output value.
+    fn has_output(&self) -> bool;
+
+    /// Reset the output value to the default state, discarding any current
+    /// value.
+    fn reset_output(&mut self) {
+        self.take_output();
+    }
+
+    /// Take the output value from the inspector, resetting it to the default
+    /// state.
+    fn take_output(&mut self) -> Self::Output;
+}
+
+impl<Db: Database, Insp> Trevm<Db, Insp>
+where
+    Insp: InspectorWithOutput<Ctx<Db>>,
+{
+    /// Take the output value from the inspector.
+    ///
+    /// This will also reset the output value in the inspector.
+    pub fn take_output(&mut self) -> Insp::Output {
+        self.inspector_mut().take_output()
+    }
+}
+
+impl<Ctx> InspectorWithOutput<Ctx> for CountInspector {
+    type Output = Self;
+
+    fn has_output(&self) -> bool {
+        self.total_opcodes() > 0
+    }
+
+    fn reset_output(&mut self) {
+        self.clear();
+    }
+
+    fn take_output(&mut self) -> Self::Output {
+        std::mem::take(self)
+    }
+}

From 9ce98116a94b0d3bb63694bb6e146f1300af8658 Mon Sep 17 00:00:00 2001
From: James <james@prestwi.ch>
Date: Mon, 25 Aug 2025 17:35:24 -0400
Subject: [PATCH 2/2] feat: add impl for 4 byte

---
 Cargo.toml                |  3 +++
 src/inspectors/mod.rs     |  3 +++
 src/inspectors/tracing.rs | 20 ++++++++++++++++++++
 3 files changed, 26 insertions(+)
 create mode 100644 src/inspectors/tracing.rs

diff --git a/Cargo.toml b/Cargo.toml
index a62e04e..2dc9ec5 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -45,6 +45,7 @@ alloy = { version = "1.0.25", default-features = false, features = [
 ] }
 
 revm = { version = "27.1", default-features = false }
+revm-inspectors = { version = "0.27.1", optional = true }
 
 dashmap = { version = "6.1.0", optional = true }
 tracing = { version = "0.1.41", optional = true }
@@ -69,6 +70,7 @@ default = [
     "call",
     "concurrent-db",
     "estimate_gas",
+    "tracing-inspectors",
     "revm/std",
     "revm/c-kzg",
     "revm/blst",
@@ -111,3 +113,4 @@ full_env_cfg = [
     "optional_eip3607",
     "optional_no_base_fee",
 ]
+tracing-inspectors = ["dep:revm-inspectors", "alloy/rpc-types-trace"]
diff --git a/src/inspectors/mod.rs b/src/inspectors/mod.rs
index fbf7df5..e54efc5 100644
--- a/src/inspectors/mod.rs
+++ b/src/inspectors/mod.rs
@@ -4,6 +4,9 @@ pub use layer::Layered;
 mod timeout;
 pub use timeout::TimeLimit;
 
+#[cfg(feature = "tracing-inspectors")]
+mod tracing;
+
 mod set;
 pub use set::InspectorSet;
 
diff --git a/src/inspectors/tracing.rs b/src/inspectors/tracing.rs
new file mode 100644
index 0000000..628fbb2
--- /dev/null
+++ b/src/inspectors/tracing.rs
@@ -0,0 +1,20 @@
+use crate::{helpers::Ctx, inspectors::InspectorWithOutput};
+use alloy::rpc::types::trace::geth::FourByteFrame;
+use revm::Database;
+use revm_inspectors::tracing::FourByteInspector;
+
+impl<Db: Database> InspectorWithOutput<Ctx<Db>> for FourByteInspector {
+    type Output = FourByteFrame;
+
+    fn has_output(&self) -> bool {
+        !self.inner().is_empty()
+    }
+
+    fn reset_output(&mut self) {
+        *self = Self::default();
+    }
+
+    fn take_output(&mut self) -> Self::Output {
+        std::mem::take(self).into()
+    }
+}