From 13d0d5592cbc11e9f43299c4317fc18fd6cd9d85 Mon Sep 17 00:00:00 2001
From: Hazel OHearn <gygaxis@zingolabs.org>
Date: Thu, 1 Dec 2022 16:15:10 -0400
Subject: [PATCH 1/4] Add spends/outputs getter fns to builders for use in
 change calculation

---
 CHANGELOG.md   |  4 +++-
 src/builder.rs | 43 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b66e0f428..ab9f7f447 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -33,7 +33,9 @@ and this project adheres to Rust's notion of
   - `impl memuse::DynamicUsage for Nullifier`
 - `orchard::note_encryption`:
   - `impl memuse::DynamicUsage for OrchardDomain`
-- `orchard::builder::SpendInfo::new`
+- `orchard::builder`:
+  - `{SpendInfo::new, InputView, OutputView}`
+  - `Builder::{spends, outputs}`
 - `orchard::circuit::Circuit::from_action_context`
 - impls of `Eq` for:
   - `orchard::zip32::ChildIndex`
diff --git a/src/builder.rs b/src/builder.rs
index ee5203e6a..96ef4cb0e 100644
--- a/src/builder.rs
+++ b/src/builder.rs
@@ -345,6 +345,16 @@ impl Builder {
         Ok(())
     }
 
+    /// Returns the action spend components that will be produced by the transaction being constructed
+    pub fn spends(&self) -> &Vec<impl InputView<()>> {
+        &self.spends
+    }
+
+    /// Returns the action output components that will be produced by the transaction being constructed
+    pub fn outputs(&self) -> &Vec<impl OutputView> {
+        &self.recipients
+    }
+
     /// The net value of the bundle to be built. The value of all spends,
     /// minus the value of all outputs.
     ///
@@ -711,6 +721,39 @@ impl<V> Bundle<InProgress<Proof, PartiallyAuthorized>, V> {
     }
 }
 
+/// A trait that provides a minimized view of an Orchard input suitable for use in
+/// fee and change calculation.
+pub trait InputView<NoteRef> {
+    /// An identifier for the input being spent.
+    fn note_id(&self) -> &NoteRef;
+    /// The value of the input being spent.
+    fn value<V: From<u64>>(&self) -> V;
+}
+
+impl InputView<()> for SpendInfo {
+    fn note_id(&self) -> &() {
+        // The builder does not make use of note identifiers, so we can just return the unit value.
+        &()
+    }
+
+    fn value<V: From<u64>>(&self) -> V {
+        V::from(self.note.value().inner())
+    }
+}
+
+/// A trait that provides a minimized view of an Orchard output suitable for use in
+/// fee and change calculation.
+pub trait OutputView {
+    /// The value of the output being produced.
+    fn value<V: From<u64>>(&self) -> V;
+}
+
+impl OutputView for RecipientInfo {
+    fn value<V: From<u64>>(&self) -> V {
+        V::from(self.value.inner())
+    }
+}
+
 /// Generators for property testing.
 #[cfg(any(test, feature = "test-dependencies"))]
 #[cfg_attr(docsrs, doc(cfg(feature = "test-dependencies")))]

From c34632746ff0bb759969360b31b1e9eca4b945c9 Mon Sep 17 00:00:00 2001
From: Hazel OHearn <gygaxis@protonmail.com>
Date: Thu, 8 Dec 2022 10:59:36 -0400
Subject: [PATCH 2/4] fix changelog additions

---
 CHANGELOG.md | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index ab9f7f447..a553528a1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,8 @@ and this project adheres to Rust's notion of
 ## [Unreleased]
 ### Added
 - `orchard::builder`:
+  - `{SpendInfo::new, InputView, OutputView}`
+  - `Builder::{spends, outputs}`
   - `SpendError` 
   - `OutputError` 
 
@@ -33,9 +35,6 @@ and this project adheres to Rust's notion of
   - `impl memuse::DynamicUsage for Nullifier`
 - `orchard::note_encryption`:
   - `impl memuse::DynamicUsage for OrchardDomain`
-- `orchard::builder`:
-  - `{SpendInfo::new, InputView, OutputView}`
-  - `Builder::{spends, outputs}`
 - `orchard::circuit::Circuit::from_action_context`
 - impls of `Eq` for:
   - `orchard::zip32::ChildIndex`

From cd8a39bd0c79561c6be235dccfe308a7ba05e861 Mon Sep 17 00:00:00 2001
From: Gygaxis Vainhardt <gygaxis@zingolabs.org>
Date: Thu, 8 Dec 2022 17:23:35 -0400
Subject: [PATCH 3/4] Format comments

Co-authored-by: Kris Nuttycombe <kris@nutty.land>
---
 src/builder.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/builder.rs b/src/builder.rs
index 96ef4cb0e..ab4f56c13 100644
--- a/src/builder.rs
+++ b/src/builder.rs
@@ -345,12 +345,14 @@ impl Builder {
         Ok(())
     }
 
-    /// Returns the action spend components that will be produced by the transaction being constructed
+    /// Returns the action spend components that will be produced by the 
+    /// transaction being constructed
     pub fn spends(&self) -> &Vec<impl InputView<()>> {
         &self.spends
     }
 
-    /// Returns the action output components that will be produced by the transaction being constructed
+    /// Returns the action output components that will be produced by the
+    /// transaction being constructed
     pub fn outputs(&self) -> &Vec<impl OutputView> {
         &self.recipients
     }

From b64d6ba01e6754d9af8ec28d85852df1a5e4fd6b Mon Sep 17 00:00:00 2001
From: Gygaxis Vainhardt <gygaxis@zingolabs.org>
Date: Tue, 3 Jan 2023 17:34:28 -0400
Subject: [PATCH 4/4] Update src/builder.rs

Co-authored-by: Kris Nuttycombe <kris@nutty.land>
---
 src/builder.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/builder.rs b/src/builder.rs
index ab4f56c13..5586f54d4 100644
--- a/src/builder.rs
+++ b/src/builder.rs
@@ -345,7 +345,7 @@ impl Builder {
         Ok(())
     }
 
-    /// Returns the action spend components that will be produced by the 
+    /// Returns the action spend components that will be produced by the
     /// transaction being constructed
     pub fn spends(&self) -> &Vec<impl InputView<()>> {
         &self.spends