From 2153c66d1bb6bb796a4dc96258b7139cd424bca7 Mon Sep 17 00:00:00 2001
From: Martin Hoffmann <martin@nlnetlabs.nl>
Date: Wed, 4 Mar 2020 14:15:46 +0100
Subject: [PATCH 1/2] Move extending a Captured into a CapturedBuilder.

---
 Cargo.toml      |  2 +-
 src/captured.rs | 76 ++++++++++++++++++++++++++++++++++++++++---------
 src/lib.rs      |  2 +-
 3 files changed, 65 insertions(+), 15 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 27b0c1a..0dd16b7 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "bcder"
-version = "0.4.3-pre"
+version = "0.5.0-pre"
 edition = "2018"
 authors = ["The NLnet Labs RPKI Team <rpki@nlnetlabs.nl>"]
 description = "Handling of data encoded in BER, CER, and DER."
diff --git a/src/captured.rs b/src/captured.rs
index b9ec5c5..db03682 100644
--- a/src/captured.rs
+++ b/src/captured.rs
@@ -3,7 +3,7 @@
 //! This is a private module. Its public items are re-exported by the parent.
 
 use std::{fmt, io, ops};
-use bytes::Bytes;
+use bytes::{Bytes, BytesMut};
 use crate::{decode, encode};
 use crate::mode::Mode;
 
@@ -62,9 +62,9 @@ impl Captured {
     /// with the given mode, and returns the resulting data as a captured
     /// value.
     pub fn from_values<V: encode::Values>(mode: Mode, values: V) -> Self {
-        let mut res = Self::new(Bytes::new(), mode);
-        res.extend(values);
-        res
+        let mut builder = Self::builder(mode);
+        builder.extend(values);
+        builder.freeze()
     }
 
     /// Creates a new empty captured value in the given mode.
@@ -75,15 +75,17 @@ impl Captured {
         }
     }
 
-    /// Extends the captured value by encoding the given values.
+    /// Crates a builder for a captured value in the given mode.
+    pub fn builder(mode: Mode) -> CapturedBuilder {
+        CapturedBuilder::new(mode)
+    }
+
+    /// Converts the captured values into a builder in order to add new values.
     ///
-    /// The function encodes the given values in the captured value’s own mode
-    /// and places the encoded content at the end of the captured value.
-    pub fn extend<V: encode::Values>(&mut self, values: V) {
-        values.write_encoded(
-            self.mode,
-            &mut CapturedWriter(&mut self.bytes)
-        ).unwrap()
+    /// Because the captured values might be shared, this requires copying the
+    /// underlying data.
+    pub fn into_builder(self) -> CapturedBuilder {
+        self.into()
     }
 
     /// Decodes the full content using the provided function argument.
@@ -188,9 +190,57 @@ impl fmt::Debug for Captured {
 }
 
 
+//------------ CapturedBuilder -----------------------------------------------
+
+pub struct CapturedBuilder {
+    bytes: BytesMut,
+    mode: Mode,
+}
+
+impl CapturedBuilder {
+    pub fn new(mode: Mode) -> Self {
+        CapturedBuilder {
+            bytes: BytesMut::new(),
+            mode
+        }
+    }
+
+    pub fn with_capacity(capacity: usize, mode: Mode) -> Self {
+        CapturedBuilder {
+            bytes: BytesMut::with_capacity(capacity),
+            mode
+        }
+    }
+
+    /// Extends the captured value by encoding the given values.
+    ///
+    /// The function encodes the given values in the captured value’s own mode
+    /// and places the encoded content at the end of the captured value.
+    pub fn extend<V: encode::Values>(&mut self, values: V) {
+        values.write_encoded(
+            self.mode,
+            &mut CapturedWriter(&mut self.bytes)
+        ).unwrap()
+    }
+
+    pub fn freeze(self) -> Captured {
+        Captured::new(self.bytes.freeze(), self.mode)
+    }
+}
+
+impl From<Captured> for CapturedBuilder {
+    fn from(src: Captured) -> Self {
+        CapturedBuilder {
+            bytes: src.bytes.as_ref().into(),
+            mode: src.mode
+        }
+    }
+}
+
+
 //------------ CapturedWriter ------------------------------------------------
 
-struct CapturedWriter<'a>(&'a mut Bytes);
+struct CapturedWriter<'a>(&'a mut BytesMut);
 
 impl<'a> io::Write for CapturedWriter<'a> {
     fn write(&mut self, buf: &[u8]) -> Result<usize, io::Error> {
diff --git a/src/lib.rs b/src/lib.rs
index c6cc9df..948524d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -36,7 +36,7 @@
 
 //--- Re-exports
 
-pub use self::captured::Captured;
+pub use self::captured::{Captured, CapturedBuilder};
 pub use self::int::{Integer, Unsigned};
 pub use self::mode::Mode;
 pub use self::oid::{ConstOid, Oid};

From 3235a2cf43af449ca25d78dac571355459d1d5ab Mon Sep 17 00:00:00 2001
From: Martin Hoffmann <martin@nlnetlabs.nl>
Date: Wed, 4 Mar 2020 14:35:20 +0100
Subject: [PATCH 2/2] Update Changelog.

---
 Changelog.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Changelog.md b/Changelog.md
index ecc2caf..4fc8432 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -4,12 +4,17 @@
 
 Breaking
 
+* Move extending a `Captured` to an explicit `CapturedBuilder`. This
+  becomes necessary with bytes 0.5. [(#46)]
+
 New
 
 Bug Fixes
 
 Dependencies
 
+[(#46)]: https://github.com/NLnetLabs/bcder/pull/46
+
 
 ## 0.4.2