Add basic gitignore functionality

No support for wildcards and exact matches might screw up nested
directories. The Globbing functionality seems like its going to be a
pain to properly match up.

src/main.rs

@@ -1,6 +1,6 @@
 use rack::config::Config;
 use rack::filematch::*;
-use std::fs::{self, File};
+use std::fs::{self, DirEntry, File};
 use std::io;
 use std::io::prelude::*;
 use std::path::Path;
@@ -19,7 +19,9 @@ fn main() {
         }
     };
 
-    let results = traverse_dir(&config, path, |config, path| check_file(config, path));
+    let results = traverse_dir(&config, path, Option::None, |config, path| {
+        check_file(config, path)
+    });
     match results {
         Result::Ok(matches) if matches.len() == 0 => println!("No matches :("),
         Result::Ok(matches) => print_report(&config, &matches),
@@ -30,15 +32,46 @@ fn main() {
 fn traverse_dir(
     config: &Config,
     dir: &Path,
+    gitignore_entries: Option<Vec<String>>,
     operation: fn(&Config, &Path) -> io::Result<FileMatch>,
 ) -> io::Result<Vec<FileMatch>> {
     let mut matches: Vec<FileMatch> = Vec::new();
-    for entry in fs::read_dir(dir)? {
+    let entries = fs::read_dir(dir)?.collect::<Vec<io::Result<DirEntry>>>();
+
+    let gitignore: Option<&DirEntry> = entries
+        .iter()
+        .filter_map(|entry| entry.as_ref().ok())
+        .find(|entry| entry.path().file_name().unwrap() == ".gitignore");
+
+    let gitignore = match gitignore {
+        Some(g) => {
+            let file = io::BufReader::new(File::open(g.path())?);
+            file.lines()
+                .map(|line| line.unwrap().trim().to_owned())
+                .filter(|line| line.len() > 0 && !line.starts_with('#'))
+                .collect::<Vec<String>>()
+        }
+        None => gitignore_entries.unwrap_or(Vec::new()),
+    };
+
+    for entry in entries {
         let entry = entry?;
         let file_type = entry.file_type()?;
-
+        let path = entry.path().to_str().unwrap().to_owned();
         if file_type.is_dir() {
-            let mut results = traverse_dir(&config, &entry.path(), operation)?;
+            if config.use_gitignore {
+                let should_ignore = gitignore.iter().find(|&line| path.contains(&line.clone()));
+
+                if should_ignore.unwrap_or(&String::from("")).len() > 0
+                    || entry.path().to_str().unwrap().contains("/.git")
+                {
+                    continue;
+                }
+            }
+
+            // TODO: Should borrow gitignore instead of cloning..
+            let mut results =
+                traverse_dir(&config, &entry.path(), Some(gitignore.clone()), operation)?;
             let has_results = results
                 .iter()
                 .filter({ |mat| mat.matches.len() > 0 })
@@ -49,6 +82,15 @@ fn traverse_dir(
                 matches.append(&mut results);
             }
         } else {
+            if config.use_gitignore {
+                let should_ignore = gitignore.iter().find(|&line| path.contains(&line.clone()));
+
+                if should_ignore.unwrap_or(&String::from("")).len() > 0
+                    || entry.path().to_str().unwrap().contains("/.git")
+                {
+                    continue;
+                }
+            }
             let result = operation(&config, &entry.path());
             match result {
                 Result::Ok(result) if result.matches.len() > 0 => matches.push(result),