Add side-by-side line wrapping mode

If the current line does not fit into the panel, then
it is not truncated but split into multiple lines. A
wrapping symbol is placed at the end of the line. If
the new line is short enought, it is right-aligned.

Wrapping is limited to a certain number of lines, if this
is exceeded the line is truncated by a now highlighted
truncation symbol.

Commandline argument `-S` / `--side-by-side-wrapped`.

Also adapted `--keep-plus-minus-markers` logic, required
to calculate the exact remaining panel width.

Cargo.toml

@@ -27,6 +27,7 @@ itertools = "0.10.0"
 lazy_static = "1.4"
 regex = "1.4.5"
 shell-words = "1.0.0"
+static_assertions = "1.1.0"
 structopt = "0.3.21"
 unicode-segmentation = "1.7.1"
 unicode-width = "0.1.8"

src/ansi/mod.rs

@@ -12,6 +12,7 @@ use iterator::{AnsiElementIterator, Element};
 pub const ANSI_CSI_CLEAR_TO_EOL: &str = "\x1b[0K";
 pub const ANSI_CSI_CLEAR_TO_BOL: &str = "\x1b[1K";
 pub const ANSI_SGR_RESET: &str = "\x1b[0m";
+pub const ANSI_SGR_REVERSE: &str = "\x1b[7m";
 
 pub fn strip_ansi_codes(s: &str) -> String {
     strip_ansi_codes_from_strings_iterator(ansi_strings_iterator(s))

src/cli.rs

@@ -217,6 +217,10 @@ pub struct Opt {
     #[structopt(short = "s", long = "side-by-side")]
     pub side_by_side: bool,
 
+    /// Display a side-by-side diff and wrap overlong lines instead of truncating them.
+    #[structopt(short = "S", long = "side-by-side-wrapped")]
+    pub side_by_side_wrapped: bool,
+
     #[structopt(long = "diff-highlight")]
     /// Emulate diff-highlight (https://github.com/git/git/tree/master/contrib/diff-highlight)
     pub diff_highlight: bool,

src/config.rs

@@ -8,15 +8,18 @@ use syntect::highlighting::Style as SyntectStyle;
 use syntect::highlighting::Theme as SyntaxTheme;
 use syntect::parsing::SyntaxSet;
 
+use crate::ansi;
 use crate::bat_utils::output::PagingMode;
 use crate::cli;
 use crate::color;
 use crate::delta::State;
 use crate::env;
 use crate::features::navigate;
 use crate::features::side_by_side;
+use crate::features::side_by_side_wrap;
 use crate::git_config::GitConfigEntry;
 use crate::style::{self, Style};
+use crate::syntect_color;
 
 pub struct Config {
     pub available_terminal_width: usize,
@@ -39,6 +42,7 @@ pub struct Config {
     pub hunk_header_style_include_line_number: bool,
     pub hyperlinks: bool,
     pub hyperlinks_file_link_format: String,
+    pub inline_hint_color: Option<SyntectStyle>,
     pub inspect_raw_lines: cli::InspectRawLines,
     pub keep_plus_minus_markers: bool,
     pub line_numbers: bool,
@@ -72,6 +76,7 @@ pub struct Config {
     pub git_plus_style: Style,
     pub show_themes: bool,
     pub side_by_side: bool,
+    pub side_by_side_wrapped: bool,
     pub side_by_side_data: side_by_side::SideBySideData,
     pub syntax_dummy_theme: SyntaxTheme,
     pub syntax_set: SyntaxSet,
@@ -81,6 +86,7 @@ pub struct Config {
     pub true_color: bool,
     pub truncation_symbol: String,
     pub whitespace_error_style: Style,
+    pub wrap_config: side_by_side_wrap::WrapConfig,
     pub zero_style: Style,
 }
 
@@ -205,6 +211,11 @@ impl From<cli::Opt> for Config {
             hyperlinks: opt.hyperlinks,
             hyperlinks_file_link_format: opt.hyperlinks_file_link_format,
             inspect_raw_lines: opt.computed.inspect_raw_lines,
+            inline_hint_color: Some(SyntectStyle {
+                // TODO: color from theme?
+                foreground: syntect_color::syntect_color_from_ansi_name("blue").unwrap(),
+                ..SyntectStyle::default()
+            }),
             keep_plus_minus_markers: opt.keep_plus_minus_markers,
             line_numbers: opt.line_numbers,
             line_numbers_left_format: opt.line_numbers_left_format,
@@ -237,14 +248,31 @@ impl From<cli::Opt> for Config {
             git_plus_style,
             show_themes: opt.show_themes,
             side_by_side: opt.side_by_side,
+            side_by_side_wrapped: opt.side_by_side_wrapped,
             side_by_side_data,
             syntax_dummy_theme: SyntaxTheme::default(),
             syntax_set: opt.computed.syntax_set,
             syntax_theme: opt.computed.syntax_theme,
             tab_width: opt.tab_width,
             tokenization_regex,
             true_color: opt.computed.true_color,
-            truncation_symbol: "→".to_string(),
+            truncation_symbol: {
+                let sym = "→";
+                if opt.side_by_side_wrapped {
+                    format!("{}{}{}", ansi::ANSI_SGR_REVERSE, sym, ansi::ANSI_SGR_RESET)
+                } else {
+                    sym.to_string()
+                }
+            },
+            wrap_config: side_by_side_wrap::WrapConfig {
+                wrap_symbol: "↵".to_string(),
+                wrap_right_symbol: "↴".to_string(),
+                right_align_symbol: "…".to_string(),
+                // TODO, support multi-character symbols, and thus store
+                // right_align_symbol_len here?
+                use_wrap_right_permille: 370,
+                max_lines: 3,
+            },
             whitespace_error_style,
             zero_style,
         }

src/delta.rs

@@ -25,6 +25,10 @@ pub enum State {
     HunkMinus(Option<String>), // In hunk; removed line (raw_line)
     HunkPlus(Option<String>), // In hunk; added line (raw_line)
     Unknown,
+    // The following elements are created when a line is wrapped to display it:
+    HunkZeroWrapped,  // Wrapped unchanged line in side-by-side mode
+    HunkMinusWrapped, // Wrapped removed line in side-by-side mode
+    HunkPlusWrapped,  // Wrapped added line in side-by-side mode
 }
 
 #[derive(Debug, PartialEq)]

src/features/line_numbers.rs

@@ -83,15 +83,18 @@ pub fn format_and_paint_line_numbers<'a>(
             line_numbers_data.line_number[Left] += 1;
             ((Some(nr_left), None), (minus_style, plus_style))
         }
+        State::HunkMinusWrapped => ((None, None), (minus_style, plus_style)),
         State::HunkZero => {
             line_numbers_data.line_number[Left] += 1;
             line_numbers_data.line_number[Right] += 1;
             ((Some(nr_left), Some(nr_right)), (zero_style, zero_style))
         }
+        State::HunkZeroWrapped => ((None, None), (zero_style, zero_style)),
         State::HunkPlus(_) => {
             line_numbers_data.line_number[Right] += 1;
             ((None, Some(nr_right)), (minus_style, plus_style))
         }
+        State::HunkPlusWrapped => ((None, None), (minus_style, plus_style)),
         _ => return Vec::new(),
     };
 
@@ -153,7 +156,7 @@ lazy_static! {
     .unwrap();
 }
 
-#[derive(Default)]
+#[derive(Default, Debug)]
 pub struct LineNumbersData<'a> {
     pub format_data: LeftRight<LineNumberFormatData<'a>>,
     pub line_number: LeftRight<usize>,

src/features/mod.rs

@@ -55,6 +55,10 @@ pub fn make_builtin_features() -> HashMap<String, BuiltinFeature> {
             "side-by-side".to_string(),
             side_by_side::make_feature().into_iter().collect(),
         ),
+        (
+            "side-by-side-wrapped".to_string(),
+            side_by_side_wrap::make_feature().into_iter().collect(),
+        ),
     ]
     .into_iter()
     .collect()
@@ -90,6 +94,7 @@ pub mod line_numbers;
 pub mod navigate;
 pub mod raw;
 pub mod side_by_side;
+pub mod side_by_side_wrap;
 
 #[cfg(test)]
 pub mod tests {