add a probe_use_gitignore option

This lets you automatically ignore any files or directories in
.gitignore (or any other input files to the git exclude mechanism).

autoload/probe/file.vim

@@ -61,8 +61,12 @@ function! probe#file#scan()
         let s:file_cache_order = s:file_cache_order[1:]
     endif
 
-    " recursively scan for files
-    let s:file_caches[s:hash] = s:scan_files(getcwd(), [], 0, {})
+    " scan for files
+    if g:probe_use_gitignore && s:is_git()
+        let s:file_caches[s:hash] = s:scan_git()
+    else
+        let s:file_caches[s:hash] = s:scan_files(getcwd(), [], 0, {})
+    endif
 
     if g:probe_cache_dir != ''
         cal s:save_cache(s:cache_filepath(), s:file_caches[s:hash])
@@ -72,6 +76,29 @@ function! probe#file#scan()
     return s:file_caches[s:hash]
 endfunction
 
+function! s:is_git()
+    let metadir_name = fnamemodify(s:find_metadir(), ':t')
+    return metadir_name == '.git'
+endfunction
+
+function! s:scan_git()
+    let files = []
+    echo "Scanning " . s:find_repo_root()
+
+    let cmd = "git ls-files -c -o --exclude-standard;" .
+             \ "git submodule foreach -q " .
+             \ "'for file in $(git ls-files -c -o --exclude-standard); " .
+             \ "do echo \"$path/$file\"; done'"
+    for name in split(system(cmd), "\n")
+        if len(files) >= g:probe_max_file_cache_size
+            break
+        endif
+        cal add(files, fnamemodify(name, ':.'))
+    endfor
+    return files
+endfunction
+
+
 function! probe#file#open(filepath)
     let filepath = escape(a:filepath, '\\|%# "')
     exe printf('edit %s', filepath)

doc/probe.txt

@@ -186,6 +186,14 @@ OPTIONS                                                        *probe-options*
 
     g:probe_ignore_files still functions normally when this option is set.
 
+|g:probe_use_gitignore|                              *g:probe_use_gitignore*
+    When in a git repository, ignore any file excluded by .gitignore (or 
+    other relevent exclude files) when scanning for files.
+    Default: (boolean) 0
+
+    g:probe_ignore_files and g:probe_use_wildignore still function normally
+    when this option is set.
+
 |g:probe_mappings|                                          *g:probe_mappings*
     Dict used to customize mappings. If a mapping is given for some operation
     the default mapping will not be created.

plugin/probe.vim

@@ -1,6 +1,6 @@
 if exists('g:probe_loaded')
     "TODO
-    "finish 
+    "finish
 endif
 let g:probe_loaded = 1
 
@@ -54,6 +54,10 @@ if !exists('g:probe_mappings')
     let g:probe_mappings = {}
 endif
 
+if !exists('g:probe_use_gitignore')
+    let g:probe_use_gitignore = 0
+endif
+
 command! -bar Probe call probe#file#find_in_repo()
 command! ProbeFindFile call probe#file#find()
 command! ProbeFindInRepo call probe#file#find_in_repo()