From 1e03b7fe924ad24a6dfa0c199d8e78e029917ff2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jelmer=20Vernoo=C4=B3?= <jelmer@jelmer.uk>
Date: Sun, 7 Jul 2024 12:30:05 +0100
Subject: [PATCH 1/2] Support Patch::write

---
 src/patch.rs | 43 ++++++++++++++++++++++++-------------------
 1 file changed, 24 insertions(+), 19 deletions(-)

diff --git a/src/patch.rs b/src/patch.rs
index c25b029..7fbab02 100644
--- a/src/patch.rs
+++ b/src/patch.rs
@@ -84,8 +84,14 @@ impl UnifiedPatch {
     }
 
     pub fn as_bytes(&self) -> Vec<u8> {
-        let mut lines = vec![
-            format!(
+        let mut bytes = Vec::new();
+        self.write(&mut bytes).unwrap();
+        bytes
+    }
+
+    pub fn write<W: std::io::Write>(&self, w: &mut W) -> std::io::Result<()> {
+        w.write_all(
+            &format!(
                 "--- {}{}\n",
                 String::from_utf8_lossy(&self.orig_name),
                 match &self.orig_ts {
@@ -94,7 +100,9 @@ impl UnifiedPatch {
                 }
             )
             .into_bytes(),
-            format!(
+        )?;
+        w.write_all(
+            &format!(
                 "+++ {}{}\n",
                 String::from_utf8_lossy(&self.mod_name),
                 match &self.mod_ts {
@@ -103,11 +111,11 @@ impl UnifiedPatch {
                 }
             )
             .into_bytes(),
-        ];
+        )?;
         for hunk in &self.hunks {
-            lines.push(hunk.as_bytes());
+            w.write_all(&hunk.as_bytes())?;
         }
-        lines.concat()
+        Ok(())
     }
 
     pub fn parse_patch<'a, I>(iter_lines: I) -> Result<Self, crate::parse::Error>
@@ -214,7 +222,16 @@ pub enum HunkLine {
 }
 
 impl HunkLine {
-    fn get_str(&self, leadchar: u8) -> Vec<u8> {
+    pub fn char(&self) -> u8 {
+        match self {
+            Self::ContextLine(_) => b' ',
+            Self::InsertLine(_) => b'+',
+            Self::RemoveLine(_) => b'-',
+        }
+    }
+
+    pub fn as_bytes(&self) -> Vec<u8> {
+        let leadchar = self.char();
         match self {
             Self::ContextLine(contents)
             | Self::InsertLine(contents)
@@ -229,18 +246,6 @@ impl HunkLine {
         }
     }
 
-    pub fn char(&self) -> u8 {
-        match self {
-            Self::ContextLine(_) => b' ',
-            Self::InsertLine(_) => b'+',
-            Self::RemoveLine(_) => b'-',
-        }
-    }
-
-    pub fn as_bytes(&self) -> Vec<u8> {
-        self.get_str(self.char())
-    }
-
     pub fn parse_line(line: &[u8]) -> Result<Self, MalformedLine> {
         if line.starts_with(b"\n") {
             Ok(Self::ContextLine(line.to_vec()))

From 72377fcd675741e37588ec6c393788d894bf0928 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jelmer=20Vernoo=C4=B3?= <jelmer@jelmer.uk>
Date: Sun, 7 Jul 2024 12:35:37 +0100
Subject: [PATCH 2/2] Fix indentation for context lines

---
 src/patch.rs | 49 +++++++++++++++++++++++++++----------------------
 1 file changed, 27 insertions(+), 22 deletions(-)

diff --git a/src/patch.rs b/src/patch.rs
index 7fbab02..5467fd2 100644
--- a/src/patch.rs
+++ b/src/patch.rs
@@ -113,7 +113,7 @@ impl UnifiedPatch {
             .into_bytes(),
         )?;
         for hunk in &self.hunks {
-            w.write_all(&hunk.as_bytes())?;
+            hunk.write(w)?;
         }
         Ok(())
     }
@@ -210,7 +210,7 @@ mod patch_tests {
                 lines: vec![super::HunkLine::ContextLine(b"foo\n".to_vec())],
             }],
         };
-        assert_eq!(patch.as_bytes(), b"--- foo\n+++ bar\n@@ -1 +2 @@\nfoo\n");
+        assert_eq!(patch.as_bytes(), b"--- foo\n+++ bar\n@@ -1 +2 @@\n foo\n");
     }
 }
 
@@ -230,22 +230,25 @@ impl HunkLine {
         }
     }
 
-    pub fn as_bytes(&self) -> Vec<u8> {
-        let leadchar = self.char();
+    pub fn contents(&self) -> &[u8] {
         match self {
-            Self::ContextLine(contents)
-            | Self::InsertLine(contents)
-            | Self::RemoveLine(contents) => {
-                let terminator = if !contents.ends_with(&b"\n"[..]) {
-                    [b"\n".to_vec(), crate::parse::NO_NL.to_vec()].concat()
-                } else {
-                    b"".to_vec()
-                };
-                [vec![leadchar], contents.clone(), terminator].concat()
-            }
+            Self::ContextLine(bytes) => bytes,
+            Self::InsertLine(bytes) => bytes,
+            Self::RemoveLine(bytes) => bytes,
         }
     }
 
+    pub fn as_bytes(&self) -> Vec<u8> {
+        let leadchar = self.char();
+        let contents = self.contents();
+        let terminator = if !contents.ends_with(&b"\n"[..]) {
+            [b"\n".to_vec(), crate::parse::NO_NL.to_vec()].concat()
+        } else {
+            b"".to_vec()
+        };
+        [vec![leadchar], contents.to_vec(), terminator].concat()
+    }
+
     pub fn parse_line(line: &[u8]) -> Result<Self, MalformedLine> {
         if line.starts_with(b"\n") {
             Ok(Self::ContextLine(line.to_vec()))
@@ -415,16 +418,18 @@ impl Hunk {
         }
     }
 
-    pub fn as_bytes(&self) -> Vec<u8> {
-        let mut lines = vec![self.get_header()];
+    pub fn write<W: std::io::Write>(&self, w: &mut W) -> std::io::Result<()> {
+        w.write_all(&self.get_header())?;
         for line in &self.lines {
-            lines.push(match line {
-                HunkLine::ContextLine(bytes) => bytes.clone(),
-                HunkLine::InsertLine(bytes) => bytes.clone(),
-                HunkLine::RemoveLine(bytes) => bytes.clone(),
-            });
+            w.write_all(&line.as_bytes())?;
         }
-        lines.concat()
+        Ok(())
+    }
+
+    pub fn as_bytes(&self) -> Vec<u8> {
+        let mut bytes = Vec::new();
+        self.write(&mut bytes).unwrap();
+        bytes
     }
 
     pub fn shift_to_mod(&self, pos: usize) -> Option<isize> {