Merge pull request #472 from dandavison/handle-hunk-header-refactor

handle hunk header refactor

5 files changed, 216 insertions, 168 deletions

diff --git a/src/delta.rs b/src/delta.rs
index 86508a73..52395f07 100644
--- a/src/delta.rs
+++ b/src/delta.rs
@@ -1,5 +1,4 @@
 use std::borrow::Cow;
-use std::fmt::Write as FmtWrite;
 use std::io::BufRead;
 use std::io::Write;
 
@@ -12,6 +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::paint::Painter;
 use crate::parse;
 use crate::style::{self, DecorationStyle};
@@ -403,165 +403,6 @@ fn handle_generic_file_meta_header_line(
     Ok(())
 }
 
-fn handle_hunk_header_line(
-    painter: &mut Painter,
-    line: &str,
-    raw_line: &str,
-    plus_file: &str,
-    config: &Config,
-) -> std::io::Result<()> {
-    let decoration_ansi_term_style;
-    let mut pad = false;
-    let draw_fn = match config.hunk_header_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 (raw_code_fragment, line_numbers) = parse::parse_hunk_header(&line);
-    // Emit the hunk header, with any requested decoration
-    if config.hunk_header_style.is_raw {
-        if config.hunk_header_style.decoration_style != DecorationStyle::NoDecoration {
-            writeln!(painter.writer)?;
-        }
-        draw_fn(
-            painter.writer,
-            &format!("{}{}", line, if pad { " " } else { "" }),
-            &format!("{}{}", raw_line, if pad { " " } else { "" }),
-            &config.decorations_width,
-            config.hunk_header_style,
-            decoration_ansi_term_style,
-        )?;
-    } else if config.hunk_header_style.is_omitted {
-        writeln!(painter.writer)?;
-    } else {
-        // Adjust the hunk-header-line before paint_lines.
-        // However in the case of color_only mode,
-        // we'll just use raw_line because we can't change raw_line structure.
-        let line = if config.color_only {
-            format!(" {}", &line)
-        } else {
-            match painter.prepare(&raw_code_fragment, false) {
-                s if !s.is_empty() => format!("{} ", s),
-                s => s,
-            }
-        };
-
-        // Prints the new line below hunk-header-line.
-        // However in the case of color_only mode,
-        // we won't print it because we can't change raw_line structure.
-        if !config.color_only {
-            writeln!(painter.writer)?;
-        }
-        if !line.is_empty() || config.hunk_header_style_include_file_path {
-            if config.hunk_header_style_include_file_path {
-                let _ = write!(
-                    &mut painter.output_buffer,
-                    "{}{} ",
-                    config.file_style.paint(plus_file),
-                    if line.is_empty() { "" } else { ":" },
-                );
-            };
-            if !line.is_empty() {
-                let lines = vec![(line, State::HunkHeader)];
-                let syntax_style_sections = Painter::get_syntax_style_sections_for_lines(
-                    &lines,
-                    &State::HunkHeader,
-                    &mut painter.highlighter,
-                    &painter.config,
-                );
-                Painter::paint_lines(
-                    syntax_style_sections,
-                    vec![vec![(config.hunk_header_style, &lines[0].0)]], // TODO: compute style from state
-                    [State::HunkHeader].iter(),
-                    &mut painter.output_buffer,
-                    config,
-                    &mut None,
-                    None,
-                    None,
-                    Some(false),
-                );
-                painter.output_buffer.pop(); // trim newline
-            }
-            draw_fn(
-                painter.writer,
-                &painter.output_buffer,
-                &painter.output_buffer,
-                &config.decorations_width,
-                config.null_style,
-                decoration_ansi_term_style,
-            )?;
-            painter.output_buffer.clear();
-        }
-    };
-
-    // Emit a full line-numbering
-    if config.line_numbers {
-        painter
-            .line_numbers_data
-            .initialize_hunk(line_numbers, plus_file.to_string());
-    // Emit a single line number.
-    // However with raw mode or color-only mode,
-    // we should prevent the output from creating new line for printing line number.
-    } else if config.line_numbers_show_first_line_number
-        && !config.hunk_header_style.is_raw
-        && !config.color_only
-    {
-        let plus_line_number = line_numbers[line_numbers.len() - 1].0;
-        let formatted_plus_line_number = if config.hyperlinks {
-            features::hyperlinks::format_osc8_file_hyperlink(
-                plus_file,
-                Some(plus_line_number),
-                &format!("{}", plus_line_number),
-                config,
-            )
-        } else {
-            Cow::from(format!("{}", plus_line_number))
-        };
-        match config.hunk_header_style.decoration_ansi_term_style() {
-            Some(style) => writeln!(
-                painter.writer,
-                "{}",
-                style.paint(formatted_plus_line_number)
-            )?,
-            None => writeln!(painter.writer, "{}", formatted_plus_line_number)?,
-        }
-    }
-    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
@@ -601,7 +442,7 @@ fn handle_hunk_line(
             };
             painter
                 .minus_lines
-                .push((painter.prepare(&line, true), state.clone()));
+                .push((painter.prepare(&line), state.clone()));
             state
         }
         Some('+') => {
@@ -618,7 +459,7 @@ fn handle_hunk_line(
             };
             painter
                 .plus_lines
-                .push((painter.prepare(&line, true), state.clone()));
+                .push((painter.prepare(&line), state.clone()));
             state
         }
         Some(' ') => {
diff --git a/src/features/line_numbers.rs b/src/features/line_numbers.rs
index e2edae3e..571ff3ff 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: &Vec<(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
new file mode 100644
index 00000000..abf042ca
--- /dev/null
+++ b/src/hunk_header.rs
@@ -0,0 +1,207 @@
+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};
+
+/// Emit the hunk header, with any requested decoration.
+pub 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 {
+        _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, painter, line, plus_file, config)?;
+    };
+
+    // Do not emit a line number in color-only mode, since the extra line would break the
+    // requirement for output lines to be in one-to-one correspondence with input lines.
+    if !config.line_numbers
+        && config.line_numbers_show_first_line_number
+        && !config.hunk_header_style.is_raw
+        && !config.color_only
+    {
+        _write_line_number(&line_numbers, painter, 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);
+    if config.hunk_header_style.decoration_style != DecorationStyle::NoDecoration {
+        writeln!(painter.writer)?;
+    }
+    draw_fn(
+        painter.writer,
+        &format!("{}{}", line, if pad { " " } else { "" }),
+        &format!("{}{}", raw_line, if pad { " " } else { "" }),
+        &config.decorations_width,
+        config.hunk_header_style,
+        decoration_ansi_term_style,
+    )?;
+    Ok(())
+}
+
+fn _write_hunk_header(
+    raw_code_fragment: &str,
+    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 line = if config.color_only {
+        format!(" {}", &line)
+    } else if !raw_code_fragment.is_empty() {
+        format!("{} ", raw_code_fragment)
+    } else {
+        "".to_string()
+    };
+
+    // Add a blank line below the hunk-header-line for readability, unless
+    // color_only mode is active.
+    if !config.color_only {
+        writeln!(painter.writer)?;
+    }
+
+    let mut have_hunk_header = false;
+    if config.hunk_header_style_include_file_path {
+        let _ = write!(
+            &mut painter.output_buffer,
+            "{}{} ",
+            config.file_style.paint(plus_file),
+            if line.is_empty() { "" } else { ":" },
+        );
+        have_hunk_header = true;
+    };
+    if !line.is_empty() {
+        let lines = vec![(line, delta::State::HunkHeader)];
+        let syntax_style_sections = Painter::get_syntax_style_sections_for_lines(
+            &lines,
+            &delta::State::HunkHeader,
+            &mut painter.highlighter,
+            &painter.config,
+        );
+        Painter::paint_lines(
+            syntax_style_sections,
+            vec![vec![(config.hunk_header_style, &lines[0].0)]], // TODO: compute style from state
+            [delta::State::HunkHeader].iter(),
+            &mut painter.output_buffer,
+            config,
+            &mut None,
+            None,
+            None,
+            Some(false),
+        );
+        painter.output_buffer.pop(); // trim newline
+        have_hunk_header = true;
+    }
+    if have_hunk_header {
+        draw_fn(
+            painter.writer,
+            &painter.output_buffer,
+            &painter.output_buffer,
+            &config.decorations_width,
+            config.null_style,
+            decoration_ansi_term_style,
+        )?;
+        painter.output_buffer.clear();
+    }
+
+    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)>,
+    painter: &mut Painter,
+    plus_file: &str,
+    config: &Config,
+) -> std::io::Result<()> {
+    let plus_line_number = line_numbers[line_numbers.len() - 1].0;
+    let formatted_plus_line_number = if config.hyperlinks {
+        features::hyperlinks::format_osc8_file_hyperlink(
+            plus_file,
+            Some(plus_line_number),
+            &format!("{}", plus_line_number),
+            config,
+        )
+    } else {
+        Cow::from(format!("{}", plus_line_number))
+    };
+    match config.hunk_header_style.decoration_ansi_term_style() {
+        Some(style) => writeln!(
+            painter.writer,
+            "{}",
+            style.paint(formatted_plus_line_number)
+        )?,
+        None => writeln!(painter.writer, "{}", formatted_plus_line_number)?,
+    }
+    Ok(())
+}
diff --git a/src/main.rs b/src/main.rs
index 31576463..75b813af 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -18,6 +18,7 @@ mod features;
 mod format;
 mod git_config;
 mod git_config_entry;
+mod hunk_header;
 mod options;
 mod paint;
 mod parse;
diff --git a/src/paint.rs b/src/paint.rs
index bbff5a8b..bf85fb13 100644
--- a/src/paint.rs
+++ b/src/paint.rs
@@ -78,8 +78,7 @@ impl<'a> Painter<'a> {
     // Terminating with newline character is necessary for many of the sublime syntax definitions to
     // highlight correctly.
     // See https://docs.rs/syntect/3.2.0/syntect/parsing/struct.SyntaxSetBuilder.html#method.add_from_folder
-    pub fn prepare(&self, line: &str, append_newline: bool) -> String {
-        let terminator = if append_newline { "\n" } else { "" };
+    pub fn prepare(&self, line: &str) -> String {
         if !line.is_empty() {
             let mut line = line.graphemes(true);
 
@@ -90,9 +89,9 @@ impl<'a> Painter<'a> {
             // TODO: Things should, but do not, work if this leading space is omitted at this stage.
             // See comment in align::Alignment::new.
             line.next();
-            format!(" {}{}", self.expand_tabs(line), terminator)
+            format!(" {}\n", self.expand_tabs(line))
         } else {
-            terminator.to_string()
+            "\n".to_string()
         }
     }
 
@@ -201,7 +200,7 @@ impl<'a> Painter<'a> {
         } else {
             None
         };
-        let lines = vec![(self.prepare(line, true), state.clone())];
+        let lines = vec![(self.prepare(line), state.clone())];
         let syntax_style_sections = Painter::get_syntax_style_sections_for_lines(
             &lines,
             &state,