Add Git support, closes #8

src/main.rs

@@ -1,59 +1,143 @@
 extern crate ansi_term;
 extern crate atty;
 extern crate console;
+extern crate git2;
 extern crate syntect;
 
 #[macro_use]
 extern crate clap;
 
-use std::io::{BufRead, Result};
+use std::collections::HashMap;
+use std::io::{self, BufRead, Result};
 use std::path::Path;
 use std::process;
 
-use ansi_term::Colour::Fixed;
+use ansi_term::Colour::{Fixed, Green, Red, Yellow};
 use atty::Stream;
 use clap::{App, AppSettings, Arg, ArgMatches};
 use console::Term;
+use git2::{DiffOptions, IntoCString, Repository};
 
 use syntect::easy::HighlightFile;
 use syntect::highlighting::ThemeSet;
 use syntect::parsing::SyntaxSet;
 use syntect::util::as_24_bit_terminal_escaped;
 
-fn print_file<P: AsRef<Path>>(filename: P) -> Result<()> {
+#[derive(Copy, Clone, Debug)]
+enum LineChange {
+    Added,
+    RemovedAbove,
+    RemovedBelow,
+    Modified,
+}
+
+type LineChanges = HashMap<u32, LineChange>;
+
+fn print_file<P: AsRef<Path>>(filename: P, line_changes: Option<LineChanges>) -> io::Result<()> {
     let ss = SyntaxSet::load_defaults_nonewlines();
     let ts = ThemeSet::load_from_folder("/home/shark/Informatik/rust/bat/themes").unwrap();
     let theme = &ts.themes["Monokai"];
 
-    let mut highlighter = HighlightFile::new(filename, &ss, theme).unwrap();
+    let mut highlighter = HighlightFile::new(filename, &ss, theme)?;
 
     let term = Term::stdout();
     let (_height, width) = term.size();
 
-    println!("{}", width);
-    let prefix = "     ┌";
+    let prefix = "───────┬";
     let line = "─".repeat(width as usize - prefix.len());
     println!("{}{}", Fixed(238).paint(prefix), Fixed(238).paint(line));
 
-    for (line_nr, maybe_line) in highlighter.reader.lines().enumerate() {
+    for (idx, maybe_line) in highlighter.reader.lines().enumerate() {
+        let line_nr = idx + 1;
         let line = maybe_line.unwrap_or("<INVALID UTF-8>".into());
         let regions = highlighter.highlight_lines.highlight(&line);
 
+        let line_change = if let Some(ref changes) = line_changes {
+            match changes.get(&(line_nr as u32)) {
+                Some(&LineChange::Added) => Green.paint("+"),
+                Some(&LineChange::RemovedAbove) => Red.paint("‾"),
+                Some(&LineChange::RemovedBelow) => Red.paint("_"),
+                Some(&LineChange::Modified) => Yellow.paint("~"),
+                _ => Fixed(1).paint(" "), // TODO
+            }
+        } else {
+            Fixed(1).paint(" ") // TODO
+        };
+
         println!(
-            "{} {} {}",
+            "{} {} {} {}",
             Fixed(244).paint(format!("{:4}", line_nr)),
+            line_change,
             Fixed(238).paint("│"),
             as_24_bit_terminal_escaped(&regions, false)
         );
     }
 
+    let prefix = "───────┴";
+    let line = "─".repeat(width as usize - prefix.len());
+    println!("{}{}", Fixed(238).paint(prefix), Fixed(238).paint(line));
+
     Ok(())
 }
 
+fn get_line_changes(filename: String) -> Option<LineChanges> {
+    let repo = Repository::open_from_env().ok()?;
+
+    let mut diff_options = DiffOptions::new();
+    diff_options.pathspec(filename.into_c_string().unwrap());
+    diff_options.context_lines(0);
+
+    let diff = repo.diff_index_to_workdir(None, Some(&mut diff_options))
+        .unwrap();
+
+    let mut line_changes: LineChanges = HashMap::new();
+
+    let mark_section =
+        |line_changes: &mut LineChanges, start: u32, end: i32, change: LineChange| {
+            for line in start..(end + 1) as u32 {
+                line_changes.insert(line, change);
+            }
+        };
+
+    let _ = diff.foreach(
+        &mut |_, _| true,
+        None,
+        Some(&mut |_, hunk| {
+            let old_lines = hunk.old_lines();
+            let new_start = hunk.new_start();
+            let new_lines = hunk.new_lines();
+            let new_end = (new_start + new_lines) as i32 - 1;
+
+            if old_lines == 0 && new_lines > 0 {
+                mark_section(&mut line_changes, new_start, new_end, LineChange::Added);
+            } else if new_lines == 0 && old_lines > 0 {
+                if new_start <= 0 {
+                    mark_section(&mut line_changes, 1, 1, LineChange::RemovedAbove);
+                } else {
+                    mark_section(
+                        &mut line_changes,
+                        new_start,
+                        new_start as i32,
+                        LineChange::RemovedBelow,
+                    );
+                }
+            } else {
+                mark_section(&mut line_changes, new_start, new_end, LineChange::Modified);
+            }
+
+            true
+        }),
+        None,
+    );
+
+    Some(line_changes)
+}
+
 fn run(matches: &ArgMatches) -> Result<()> {
     if let Some(files) = matches.values_of("file") {
         for file in files {
-            print_file(file)?;
+            let line_changes = get_line_changes(file.to_string());
+            print_file(file, line_changes)?;
         }
     }
 
@@ -88,7 +172,7 @@ fn main() {
     let result = run(&matches);
 
     if let Err(e) = result {
-        eprintln!("Error: {}", e);
+        eprintln!("{}: {}", Red.paint("bat error"), e);
         process::exit(1);
     }
 }