New option to map raw styles encountered in input

Unify handling of styles parsed from raw line and computed diff
styles. This enables syntax highlighting to be used in color-moved
sections.

Fixes #72

1 files changed, 104 insertions, 0 deletions

diff --git a/src/style.rs b/src/style.rs
index b745cf33..047b9cc9 100644
--- a/src/style.rs
+++ b/src/style.rs
@@ -1,5 +1,6 @@
 use std::borrow::Cow;
 use std::fmt;
+use std::hash::{Hash, Hasher};
 
 use lazy_static::lazy_static;
 
@@ -210,6 +211,89 @@ pub fn ansi_term_style_equality(a: ansi_term::Style, b: ansi_term::Style) -> boo
     }
 }
 
+// TODO: The equality methods were implemented first, and the equality_key
+// methods later. The former should be re-implemented in terms of the latter.
+// But why did the former not address equality of ansi_term::Color::RGB values?
+pub struct AnsiTermStyleEqualityKey {
+    attrs_key: (bool, bool, bool, bool, bool, bool, bool, bool),
+    foreground_key: Option<(u8, u8, u8, u8)>,
+    background_key: Option<(u8, u8, u8, u8)>,
+}
+
+impl PartialEq for AnsiTermStyleEqualityKey {
+    fn eq(&self, other: &Self) -> bool {
+        let option_eq = |opt_a, opt_b| match (opt_a, opt_b) {
+            (Some(a), Some(b)) => a == b,
+            (None, None) => true,
+            _ => false,
+        };
+
+        if self.attrs_key != other.attrs_key {
+            false
+        } else {
+            option_eq(self.foreground_key, other.foreground_key)
+                && option_eq(self.background_key, other.background_key)
+        }
+    }
+}
+
+impl Eq for AnsiTermStyleEqualityKey {}
+
+impl Hash for AnsiTermStyleEqualityKey {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.attrs_key.hash(state);
+        self.foreground_key.hash(state);
+        self.background_key.hash(state);
+    }
+}
+
+pub fn ansi_term_style_equality_key(style: ansi_term::Style) -> AnsiTermStyleEqualityKey {
+    let attrs_key = (
+        style.is_bold,
+        style.is_dimmed,
+        style.is_italic,
+        style.is_underline,
+        style.is_blink,
+        style.is_reverse,
+        style.is_hidden,
+        style.is_strikethrough,
+    );
+    AnsiTermStyleEqualityKey {
+        attrs_key,
+        foreground_key: style.foreground.map(ansi_term_color_equality_key),
+        background_key: style.background.map(ansi_term_color_equality_key),
+    }
+}
+
+impl fmt::Debug for AnsiTermStyleEqualityKey {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let is_set = |c: char, set: bool| -> String {
+            if set {
+                c.to_uppercase().to_string()
+            } else {
+                c.to_lowercase().to_string()
+            }
+        };
+
+        let (bold, dimmed, italic, underline, blink, reverse, hidden, strikethrough) =
+            self.attrs_key;
+        write!(
+            f,
+            "ansi_term::Style {{ {:?} {:?} {}{}{}{}{}{}{}{} }}",
+            self.foreground_key,
+            self.background_key,
+            is_set('b', bold),
+            is_set('d', dimmed),
+            is_set('i', italic),
+            is_set('u', underline),
+            is_set('l', blink),
+            is_set('r', reverse),
+            is_set('h', hidden),
+            is_set('s', strikethrough),
+        )
+    }
+}
+
 fn ansi_term_color_equality(a: Option<ansi_term::Color>, b: Option<ansi_term::Color>) -> bool {
     match (a, b) {
         (None, None) => true,
@@ -239,6 +323,26 @@ fn ansi_term_16_color_equality(a: ansi_term::Color, b: ansi_term::Color) -> bool
     )
 }
 
+fn ansi_term_color_equality_key(color: ansi_term::Color) -> (u8, u8, u8, u8) {
+    // Same (r, g, b, a) encoding as in utils::bat::terminal::to_ansi_color.
+    // When a = 0xFF, then a 256-color number is stored in the red channel, and
+    // the green and blue channels are meaningless. But a=0 signifies an RGB
+    // color.
+    let default = 0xFF;
+    match color {
+        ansi_term::Color::Fixed(0) | ansi_term::Color::Black => (0, default, default, default),
+        ansi_term::Color::Fixed(1) | ansi_term::Color::Red => (1, default, default, default),
+        ansi_term::Color::Fixed(2) | ansi_term::Color::Green => (2, default, default, default),
+        ansi_term::Color::Fixed(3) | ansi_term::Color::Yellow => (3, default, default, default),
+        ansi_term::Color::Fixed(4) | ansi_term::Color::Blue => (4, default, default, default),
+        ansi_term::Color::Fixed(5) | ansi_term::Color::Purple => (5, default, default, default),
+        ansi_term::Color::Fixed(6) | ansi_term::Color::Cyan => (6, default, default, default),
+        ansi_term::Color::Fixed(7) | ansi_term::Color::White => (7, default, default, default),
+        ansi_term::Color::Fixed(n) => (n, default, default, default),
+        ansi_term::Color::RGB(r, g, b) => (r, g, b, 0),
+    }
+}
+
 lazy_static! {
     pub static ref GIT_DEFAULT_MINUS_STYLE: Style = Style {
         ansi_term_style: ansi_term::Color::Red.normal(),