Allow styles to be specified as references to other styles

1 files changed, 429 insertions, 0 deletions

diff --git a/src/parse_styles.rs b/src/parse_styles.rs
new file mode 100644
index 00000000..d87e0585
--- /dev/null
+++ b/src/parse_styles.rs
@@ -0,0 +1,429 @@
+use std::collections::{HashMap, HashSet};
+
+use crate::cli;
+use crate::color;
+#[cfg(not(test))]
+use crate::fatal;
+use crate::git_config::GitConfigEntry;
+use crate::style::{self, Style};
+
+#[derive(Debug, Clone)]
+enum StyleReference {
+    Style(Style),
+    Reference(String),
+}
+
+fn is_style_reference(style_string: &str) -> bool {
+    style_string.ends_with("-style") && !style_string.chars().any(|c| c == ' ')
+}
+
+pub fn parse_styles(opt: &cli::Opt) -> HashMap<String, Style> {
+    let mut styles: HashMap<&str, StyleReference> = HashMap::new();
+
+    make_hunk_styles(opt, &mut styles);
+    make_commit_file_hunk_header_styles(opt, &mut styles);
+    make_line_number_styles(opt, &mut styles);
+    styles.insert(
+        "inline-hint-style",
+        style_from_str(
+            &opt.inline_hint_style,
+            None,
+            None,
+            opt.computed.true_color,
+            false,
+        ),
+    );
+    styles.insert(
+        "git-minus-style",
+        StyleReference::Style(match opt.git_config_entries.get("color.diff.old") {
+            Some(GitConfigEntry::Style(s)) => Style::from_git_str(s),
+            _ => *style::GIT_DEFAULT_MINUS_STYLE,
+        }),
+    );
+    styles.insert(
+        "git-plus-style",
+        StyleReference::Style(match opt.git_config_entries.get("color.diff.new") {
+            Some(GitConfigEntry::Style(s)) => Style::from_git_str(s),
+            _ => *style::GIT_DEFAULT_PLUS_STYLE,
+        }),
+    );
+    resolve_style_references(styles)
+}
+
+fn resolve_style_references(edges: HashMap<&str, StyleReference>) -> HashMap<String, Style> {
+    let mut resolved_styles = HashMap::new();
+
+    for starting_node in edges.keys() {
+        if resolved_styles.contains_key(*starting_node) {
+            continue;
+        }
+        let mut visited = HashSet::new();
+        let mut node = *starting_node;
+        loop {
+            if !visited.insert(node) {
+                #[cfg(not(test))]
+                fatal(format!("Your delta styles form a cycle! {:?}", visited));
+                #[cfg(test)]
+                return [("__cycle__", Style::default())]
+                    .iter()
+                    .map(|(a, b)| (a.to_string(), *b))
+                    .collect();
+            }
+            match &edges[&node] {
+                StyleReference::Style(style) => {
+                    resolved_styles.extend(visited.iter().map(|node| (node.to_string(), *style)));
+                    break;
+                }
+                StyleReference::Reference(child_node) => node = child_node,
+            }
+        }
+    }
+    resolved_styles
+}
+
+fn make_hunk_styles<'a>(opt: &'a cli::Opt, styles: &'a mut HashMap<&str, StyleReference>) {
+    let is_light_mode = opt.computed.is_light_mode;
+    let true_color = opt.computed.true_color;
+    let minus_style = style_from_str(
+        &opt.minus_style,
+        Some(Style::from_colors(
+            None,
+            Some(color::get_minus_background_color_default(
+                is_light_mode,
+                true_color,
+            )),
+        )),
+        None,
+        true_color,
+        false,
+    );
+
+    let minus_emph_style = style_from_str(
+        &opt.minus_emph_style,
+        Some(Style::from_colors(
+            None,
+            Some(color::get_minus_emph_background_color_default(
+                is_light_mode,
+                true_color,
+            )),
+        )),
+        None,
+        true_color,
+        true,
+    );
+
+    let minus_non_emph_style =
+        style_from_str(&opt.minus_non_emph_style, None, None, true_color, false);
+
+    // The style used to highlight a removed empty line when otherwise it would be invisible due to
+    // lack of background color in minus-style.
+    let minus_empty_line_marker_style = style_from_str(
+        &opt.minus_empty_line_marker_style,
+        Some(Style::from_colors(
+            None,
+            Some(color::get_minus_background_color_default(
+                is_light_mode,
+                true_color,
+            )),
+        )),
+        None,
+        true_color,
+        false,
+    );
+
+    let zero_style = style_from_str(&opt.zero_style, None, None, true_color, false);
+
+    let plus_style = style_from_str(
+        &opt.plus_style,
+        Some(Style::from_colors(
+            None,
+            Some(color::get_plus_background_color_default(
+                is_light_mode,
+                true_color,
+            )),
+        )),
+        None,
+        true_color,
+        false,
+    );
+
+    let plus_emph_style = style_from_str(
+        &opt.plus_emph_style,
+        Some(Style::from_colors(
+            None,
+            Some(color::get_plus_emph_background_color_default(
+                is_light_mode,
+                true_color,
+            )),
+        )),
+        None,
+        true_color,
+        true,
+    );
+
+    let plus_non_emph_style =
+        style_from_str(&opt.plus_non_emph_style, None, None, true_color, false);
+
+    // The style used to highlight an added empty line when otherwise it would be invisible due to
+    // lack of background color in plus-style.
+    let plus_empty_line_marker_style = style_from_str(
+        &opt.plus_empty_line_marker_style,
+        Some(Style::from_colors(
+            None,
+            Some(color::get_plus_background_color_default(
+                is_light_mode,
+                true_color,
+            )),
+        )),
+        None,
+        true_color,
+        false,
+    );
+
+    let whitespace_error_style =
+        style_from_str(&opt.whitespace_error_style, None, None, true_color, false);
+
+    styles.extend([
+        ("minus-style", minus_style),
+        ("minus-emph-style", minus_emph_style),
+        ("minus-non-emph-style", minus_non_emph_style),
+        (
+            "minus-empty-line-marker-style",
+            minus_empty_line_marker_style,
+        ),
+        ("zero-style", zero_style),
+        ("plus-style", plus_style),
+        ("plus-emph-style", plus_emph_style),
+        ("plus-non-emph-style", plus_non_emph_style),
+        ("plus-empty-line-marker-style", plus_empty_line_marker_style),
+        ("whitespace-error-style", whitespace_error_style),
+    ])
+}
+
+fn make_line_number_styles(opt: &cli::Opt, styles: &mut HashMap<&str, StyleReference>) {
+    let true_color = opt.computed.true_color;
+    let line_numbers_left_style =
+        style_from_str(&opt.line_numbers_left_style, None, None, true_color, false);
+
+    let line_numbers_minus_style =
+        style_from_str(&opt.line_numbers_minus_style, None, None, true_color, false);
+
+    let line_numbers_zero_style =
+        style_from_str(&opt.line_numbers_zero_style, None, None, true_color, false);
+
+    let line_numbers_plus_style =
+        style_from_str(&opt.line_numbers_plus_style, None, None, true_color, false);
+
+    let line_numbers_right_style =
+        style_from_str(&opt.line_numbers_right_style, None, None, true_color, false);
+
+    styles.extend([
+        ("line-numbers-minus-style", line_numbers_minus_style),
+        ("line-numbers-zero-style", line_numbers_zero_style),
+        ("line-numbers-plus-style", line_numbers_plus_style),
+        ("line-numbers-left-style", line_numbers_left_style),
+        ("line-numbers-right-style", line_numbers_right_style),
+    ])
+}
+
+fn make_commit_file_hunk_header_styles(opt: &cli::Opt, styles: &mut HashMap<&str, StyleReference>) {
+    let true_color = opt.computed.true_color;
+    styles.extend([
+        ("commit-style",
+            style_from_str_with_handling_of_special_decoration_attributes_and_respecting_deprecated_foreground_color_arg(
+                &opt.commit_style,
+                None,
+                Some(&opt.commit_decoration_style),
+                opt.deprecated_commit_color.as_deref(),
+                true_color,
+                false,
+            )
+        ),
+        ("file-style",
+            style_from_str_with_handling_of_special_decoration_attributes_and_respecting_deprecated_foreground_color_arg(
+                &opt.file_style,
+                None,
+                Some(&opt.file_decoration_style),
+                opt.deprecated_file_color.as_deref(),
+                true_color,
+                false,
+            )
+        ),
+        ("hunk-header-style",
+            style_from_str_with_handling_of_special_decoration_attributes_and_respecting_deprecated_foreground_color_arg(
+                &opt.hunk_header_style,
+                None,
+                Some(&opt.hunk_header_decoration_style),
+                opt.deprecated_hunk_color.as_deref(),
+                true_color,
+                false,
+            )
+        ),
+        ("hunk-header-file-style",
+            style_from_str_with_handling_of_special_decoration_attributes(
+                &opt.hunk_header_file_style,
+                None,
+                None,
+                true_color,
+                false,
+            )
+        ),
+        ("hunk-header-line-number-style",
+            style_from_str_with_handling_of_special_decoration_attributes(
+                &opt.hunk_header_line_number_style,
+                None,
+                None,
+                true_color,
+                false,
+            )
+        ),
+    ]);
+}
+
+fn style_from_str(
+    style_string: &str,
+    default: Option<Style>,
+    decoration_style_string: Option<&str>,
+    true_color: bool,
+    is_emph: bool,
+) -> StyleReference {
+    if is_style_reference(style_string) {
+        StyleReference::Reference(style_string.to_owned())
+    } else {
+        StyleReference::Style(Style::from_str(
+            style_string,
+            default,
+            decoration_style_string,
+            true_color,
+            is_emph,
+        ))
+    }
+}
+
+fn style_from_str_with_handling_of_special_decoration_attributes(
+    style_string: &str,
+    default: Option<Style>,
+    decoration_style_string: Option<&str>,
+    true_color: bool,
+    is_emph: bool,
+) -> StyleReference {
+    if is_style_reference(style_string) {
+        StyleReference::Reference(style_string.to_owned())
+    } else {
+        StyleReference::Style(
+            Style::from_str_with_handling_of_special_decoration_attributes(
+                style_string,
+                default,
+                decoration_style_string,
+                true_color,
+                is_emph,
+            ),
+        )
+    }
+}
+
+fn style_from_str_with_handling_of_special_decoration_attributes_and_respecting_deprecated_foreground_color_arg(
+    style_string: &str,
+    default: Option<Style>,
+    decoration_style_string: Option<&str>,
+    deprecated_foreground_color_arg: Option<&str>,
+    true_color: bool,
+    is_emph: bool,
+) -> StyleReference {
+    if is_style_reference(style_string) {
+        StyleReference::Reference(style_string.to_owned())
+    } else {
+        StyleReference::Style(Style::from_str_with_handling_of_special_decoration_attributes_and_respecting_deprecated_foreground_color_arg(
+            style_string,
+            default,
+            decoration_style_string,
+            deprecated_foreground_color_arg,
+            true_color,
+            is_emph
+        ))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_resolve_style_references_1() {
+        let style_1 = Style::default();
+        let mut style_2 = Style::default();
+        style_2.is_syntax_highlighted = !style_1.is_syntax_highlighted;
+
+        let edges: HashMap<&str, StyleReference> = [
+            ("a", StyleReference::Style(style_1)),
+            ("b", StyleReference::Reference("c".to_string())),
+            ("c", StyleReference::Style(style_2)),
+        ]
+        .iter()
+        .map(|(a, b)| (*a, b.clone()))
+        .collect();
+
+        let expected = [("a", style_1), ("b", style_2), ("c", style_2)]
+            .iter()
+            .map(|(a, b)| (a.to_string(), *b))
+            .collect();
+
+        assert_eq!(resolve_style_references(edges), expected);
+    }
+
+    #[test]
+    fn test_resolve_style_references_2() {
+        let style_1 = Style::default();
+        let mut style_2 = Style::default();
+        style_2.is_syntax_highlighted = !style_1.is_syntax_highlighted;
+
+        let edges: HashMap<&str, StyleReference> = [
+            ("a", StyleReference::Reference("b".to_string())),
+            ("b", StyleReference::Reference("c".to_string())),
+            ("c", StyleReference::Style(style_1)),
+            ("d", StyleReference::Reference("b".to_string())),
+            ("e", StyleReference::Reference("a".to_string())),
+            ("f", StyleReference::Style(style_2)),
+            ("g", StyleReference::Reference("f".to_string())),
+            ("h", StyleReference::Reference("g".to_string())),
+            ("i", StyleReference::Reference("g".to_string())),
+        ]
+        .iter()
+        .map(|(a, b)| (*a, b.clone()))
+        .collect();
+
+        let expected = [
+            ("a", style_1),
+            ("b", style_1),
+            ("c", style_1),
+            ("d", style_1),
+            ("e", style_1),
+            ("f", style_2),
+            ("g", style_2),
+            ("h", style_2),
+            ("i", style_2),
+        ]
+        .iter()
+        .map(|(a, b)| (a.to_string(), *b))
+        .collect();
+
+        assert_eq!(resolve_style_references(edges), expected);
+    }
+
+    #[test]
+    fn test_resolve_style_references_cycle() {
+        let edges: HashMap<&str, StyleReference> = [
+            ("a", StyleReference::Reference("b".to_string())),
+            ("b", StyleReference::Reference("c".to_string())),
+            ("c", StyleReference::Reference("a".to_string())),
+        ]
+        .iter()
+        .map(|(a, b)| (*a, b.clone()))
+        .collect();
+
+        assert_eq!(
+            resolve_style_references(edges).keys().next().unwrap(),
+            "__cycle__"
+        );
+    }
+}