Move line number refactoring (#474)

* Move handle_hunk_header_line back into delta.rs

* Clean up draw_function API

* Clippy

4 files changed, 84 insertions, 173 deletions

diff --git a/src/delta.rs b/src/delta.rs
index 52395f07..620e00e8 100644
--- a/src/delta.rs
+++ b/src/delta.rs
@@ -11,7 +11,7 @@ use crate::config::Config;
 use crate::draw;
 use crate::features;
 use crate::format;
-use crate::hunk_header::handle_hunk_header_line;
+use crate::hunk_header;
 use crate::paint::Painter;
 use crate::parse;
 use crate::style::{self, DecorationStyle};
@@ -257,46 +257,8 @@ fn handle_commit_meta_header_line(
     if config.commit_style.is_omitted {
         return Ok(());
     }
-    let decoration_ansi_term_style;
-    let mut pad = false;
-    let draw_fn = match config.commit_style.decoration_style {
-        DecorationStyle::Box(style) => {
-            pad = true;
-            decoration_ansi_term_style = style;
-            draw::write_boxed
-        }
-        DecorationStyle::BoxWithUnderline(style) => {
-            pad = true;
-            decoration_ansi_term_style = style;
-            draw::write_boxed_with_underline
-        }
-        DecorationStyle::BoxWithOverline(style) => {
-            pad = true;
-            decoration_ansi_term_style = style;
-            draw::write_boxed // TODO: not implemented
-        }
-        DecorationStyle::BoxWithUnderOverline(style) => {
-            pad = true;
-            decoration_ansi_term_style = style;
-            draw::write_boxed // TODO: not implemented
-        }
-        DecorationStyle::Underline(style) => {
-            decoration_ansi_term_style = style;
-            draw::write_underlined
-        }
-        DecorationStyle::Overline(style) => {
-            decoration_ansi_term_style = style;
-            draw::write_overlined
-        }
-        DecorationStyle::UnderOverline(style) => {
-            decoration_ansi_term_style = style;
-            draw::write_underoverlined
-        }
-        DecorationStyle::NoDecoration => {
-            decoration_ansi_term_style = ansi_term::Style::new();
-            draw::write_no_decoration
-        }
-    };
+    let (mut draw_fn, pad, decoration_ansi_term_style) =
+        draw::get_draw_function(config.commit_style.decoration_style);
     let (formatted_line, formatted_raw_line) = if config.hyperlinks {
         (
             features::hyperlinks::format_commit_line_with_osc8_commit_hyperlink(line, config),
@@ -346,46 +308,8 @@ fn handle_generic_file_meta_header_line(
     if config.file_style.is_omitted && !config.color_only {
         return Ok(());
     }
-    let decoration_ansi_term_style;
-    let mut pad = false;
-    let draw_fn = match config.file_style.decoration_style {
-        DecorationStyle::Box(style) => {
-            pad = true;
-            decoration_ansi_term_style = style;
-            draw::write_boxed
-        }
-        DecorationStyle::BoxWithUnderline(style) => {
-            pad = true;
-            decoration_ansi_term_style = style;
-            draw::write_boxed_with_underline
-        }
-        DecorationStyle::BoxWithOverline(style) => {
-            pad = true;
-            decoration_ansi_term_style = style;
-            draw::write_boxed // TODO: not implemented
-        }
-        DecorationStyle::BoxWithUnderOverline(style) => {
-            pad = true;
-            decoration_ansi_term_style = style;
-            draw::write_boxed // TODO: not implemented
-        }
-        DecorationStyle::Underline(style) => {
-            decoration_ansi_term_style = style;
-            draw::write_underlined
-        }
-        DecorationStyle::Overline(style) => {
-            decoration_ansi_term_style = style;
-            draw::write_overlined
-        }
-        DecorationStyle::UnderOverline(style) => {
-            decoration_ansi_term_style = style;
-            draw::write_underoverlined
-        }
-        DecorationStyle::NoDecoration => {
-            decoration_ansi_term_style = ansi_term::Style::new();
-            draw::write_no_decoration
-        }
-    };
+    let (mut draw_fn, pad, decoration_ansi_term_style) =
+        draw::get_draw_function(config.file_style.decoration_style);
     // Prints the new line below file-meta-line.
     // However in the case of color_only mode,
     // we won't print it because we can't change raw_line structure.
@@ -403,6 +327,38 @@ fn handle_generic_file_meta_header_line(
     Ok(())
 }
 
+/// Emit the hunk header, with any requested decoration.
+fn handle_hunk_header_line(
+    painter: &mut Painter,
+    line: &str,
+    raw_line: &str,
+    plus_file: &str,
+    config: &Config,
+) -> std::io::Result<()> {
+    let (raw_code_fragment, line_numbers) = parse::parse_hunk_header(&line);
+    if config.line_numbers {
+        painter
+            .line_numbers_data
+            .initialize_hunk(&line_numbers, plus_file.to_string());
+    }
+
+    if config.hunk_header_style.is_raw {
+        hunk_header::write_hunk_header_raw(painter, line, raw_line, config)?;
+    } else if config.hunk_header_style.is_omitted {
+        writeln!(painter.writer)?;
+    } else {
+        hunk_header::write_hunk_header(
+            &raw_code_fragment,
+            &line_numbers,
+            painter,
+            line,
+            plus_file,
+            config,
+        )?;
+    };
+    Ok(())
+}
+
 /// Handle a hunk line, i.e. a minus line, a plus line, or an unchanged line.
 // In the case of a minus or plus line, we store the line in a
 // buffer. When we exit the changed region we process the collected
diff --git a/src/draw.rs b/src/draw.rs
index 59c0498a..d7edd8cd 100644
--- a/src/draw.rs
+++ b/src/draw.rs
@@ -3,9 +3,39 @@ use std::io::Write;
 
 use crate::ansi;
 use crate::cli::Width;
-use crate::style::Style;
+use crate::style::{DecorationStyle, Style};
 
-pub fn write_no_decoration(
+pub type DrawFunction =
+    dyn FnMut(&mut dyn Write, &str, &str, &Width, Style, ansi_term::Style) -> std::io::Result<()>;
+
+pub fn get_draw_function(
+    decoration_style: DecorationStyle,
+) -> (Box<DrawFunction>, bool, ansi_term::Style) {
+    match decoration_style {
+        DecorationStyle::Box(style) => (Box::new(write_boxed), true, style),
+        DecorationStyle::BoxWithUnderline(style) => {
+            (Box::new(write_boxed_with_underline), true, style)
+        }
+        DecorationStyle::BoxWithOverline(style) => {
+            // TODO: not implemented
+            (Box::new(write_boxed), true, style)
+        }
+        DecorationStyle::BoxWithUnderOverline(style) => {
+            // TODO: not implemented
+            (Box::new(write_boxed), true, style)
+        }
+        DecorationStyle::Underline(style) => (Box::new(write_underlined), false, style),
+        DecorationStyle::Overline(style) => (Box::new(write_overlined), false, style),
+        DecorationStyle::UnderOverline(style) => (Box::new(write_underoverlined), false, style),
+        DecorationStyle::NoDecoration => (
+            Box::new(write_no_decoration),
+            false,
+            ansi_term::Style::new(),
+        ),
+    }
+}
+
+fn write_no_decoration(
     writer: &mut dyn Write,
     text: &str,
     raw_text: &str,
@@ -23,7 +53,7 @@ pub fn write_no_decoration(
 
 /// Write text to stream, surrounded by a box, leaving the cursor just
 /// beyond the bottom right corner.
-pub fn write_boxed(
+fn write_boxed(
     writer: &mut dyn Write,
     text: &str,
     raw_text: &str,
@@ -51,7 +81,7 @@ pub fn write_boxed(
 
 /// Write text to stream, surrounded by a box, and extend a line from
 /// the bottom right corner.
-pub fn write_boxed_with_underline(
+fn write_boxed_with_underline(
     writer: &mut dyn Write,
     text: &str,
     raw_text: &str,
@@ -92,7 +122,7 @@ enum UnderOverline {
     Underover,
 }
 
-pub fn write_underlined(
+fn write_underlined(
     writer: &mut dyn Write,
     text: &str,
     raw_text: &str,
@@ -111,7 +141,7 @@ pub fn write_underlined(
     )
 }
 
-pub fn write_overlined(
+fn write_overlined(
     writer: &mut dyn Write,
     text: &str,
     raw_text: &str,
@@ -130,7 +160,7 @@ pub fn write_overlined(
     )
 }
 
-pub fn write_underoverlined(
+fn write_underoverlined(
     writer: &mut dyn Write,
     text: &str,
     raw_text: &str,
diff --git a/src/features/line_numbers.rs b/src/features/line_numbers.rs
index 571ff3ff..469f4118 100644
--- a/src/features/line_numbers.rs
+++ b/src/features/line_numbers.rs
@@ -188,7 +188,7 @@ impl<'a> LineNumbersData<'a> {
     }
 
     /// Initialize line number data for a hunk.
-    pub fn initialize_hunk(&mut self, line_numbers: &Vec<(usize, usize)>, plus_file: String) {
+    pub fn initialize_hunk(&mut self, line_numbers: &[(usize, usize)], plus_file: String) {
         // Typically, line_numbers has length 2: an entry for the minus file, and one for the plus
         // file. In the case of merge commits, it may be longer.
         self.hunk_minus_line_number = line_numbers[0].0;
diff --git a/src/hunk_header.rs b/src/hunk_header.rs
index 2f54dd79..b44a6330 100644
--- a/src/hunk_header.rs
+++ b/src/hunk_header.rs
@@ -1,55 +1,21 @@
 use std::borrow::Cow;
 use std::fmt::Write as FmtWrite;
-use std::io::Write;
 
-use crate::cli;
 use crate::config::Config;
 use crate::delta;
 use crate::draw;
 use crate::features;
 use crate::paint::Painter;
-use crate::parse;
-use crate::style::{self, DecorationStyle};
+use crate::style::DecorationStyle;
 
-/// Emit the hunk header, with any requested decoration.
-pub fn handle_hunk_header_line(
+pub fn write_hunk_header_raw(
     painter: &mut Painter,
     line: &str,
     raw_line: &str,
-    plus_file: &str,
     config: &Config,
 ) -> std::io::Result<()> {
-    let (raw_code_fragment, line_numbers) = parse::parse_hunk_header(&line);
-    if config.line_numbers {
-        painter
-            .line_numbers_data
-            .initialize_hunk(&line_numbers, plus_file.to_string());
-    }
-
-    if config.hunk_header_style.is_raw {
-        _write_hunk_header_raw(painter, line, raw_line, config)?;
-    } else if config.hunk_header_style.is_omitted {
-        writeln!(painter.writer)?;
-    } else {
-        _write_hunk_header(
-            &raw_code_fragment,
-            &line_numbers,
-            painter,
-            line,
-            plus_file,
-            config,
-        )?;
-    };
-    Ok(())
-}
-
-fn _write_hunk_header_raw(
-    painter: &mut Painter,
-    line: &str,
-    raw_line: &str,
-    config: &Config,
-) -> std::io::Result<()> {
-    let (mut draw_fn, pad, decoration_ansi_term_style) = _get_draw_fn(config);
+    let (mut draw_fn, pad, decoration_ansi_term_style) =
+        draw::get_draw_function(config.hunk_header_style.decoration_style);
     if config.hunk_header_style.decoration_style != DecorationStyle::NoDecoration {
         writeln!(painter.writer)?;
     }
@@ -64,15 +30,16 @@ fn _write_hunk_header_raw(
     Ok(())
 }
 
-fn _write_hunk_header(
+pub fn write_hunk_header(
     raw_code_fragment: &str,
-    line_numbers: &Vec<(usize, usize)>,
+    line_numbers: &[(usize, usize)],
     painter: &mut Painter,
     line: &str,
     plus_file: &str,
     config: &Config,
 ) -> std::io::Result<()> {
-    let (mut draw_fn, _, decoration_ansi_term_style) = _get_draw_fn(config);
+    let (mut draw_fn, _, decoration_ansi_term_style) =
+        draw::get_draw_function(config.hunk_header_style.decoration_style);
     let line = if config.color_only {
         format!(" {}", &line)
     } else if !raw_code_fragment.is_empty() {
@@ -149,50 +116,8 @@ fn _write_hunk_header(
     Ok(())
 }
 
-fn _get_draw_fn(
-    config: &Config,
-) -> (
-    Box<
-        dyn FnMut(
-            &mut dyn Write,
-            &str,
-            &str,
-            &cli::Width,
-            style::Style,
-            ansi_term::Style,
-        ) -> std::io::Result<()>,
-    >,
-    bool,
-    ansi_term::Style,
-) {
-    match config.hunk_header_style.decoration_style {
-        DecorationStyle::Box(style) => (Box::new(draw::write_boxed), true, style),
-        DecorationStyle::BoxWithUnderline(style) => {
-            (Box::new(draw::write_boxed_with_underline), true, style)
-        }
-        DecorationStyle::BoxWithOverline(style) => {
-            // TODO: not implemented
-            (Box::new(draw::write_boxed), true, style)
-        }
-        DecorationStyle::BoxWithUnderOverline(style) => {
-            // TODO: not implemented
-            (Box::new(draw::write_boxed), true, style)
-        }
-        DecorationStyle::Underline(style) => (Box::new(draw::write_underlined), false, style),
-        DecorationStyle::Overline(style) => (Box::new(draw::write_overlined), false, style),
-        DecorationStyle::UnderOverline(style) => {
-            (Box::new(draw::write_underoverlined), false, style)
-        }
-        DecorationStyle::NoDecoration => (
-            Box::new(draw::write_no_decoration),
-            false,
-            ansi_term::Style::new(),
-        ),
-    }
-}
-
 fn _write_line_number(
-    line_numbers: &Vec<(usize, usize)>,
+    line_numbers: &[(usize, usize)],
     painter: &mut Painter,
     plus_file: &str,
     config: &Config,