builtin-add.c: optimize -A option and "git add ."

The earlier "git add -A" change was done in a quite inefficient
way (i.e. it is as unefficient as "git add -u && git add ." modulo
one fork/exec and read/write index).

When the user asks "git add .", we do not have to examine all paths
we encounter and perform the excluded() and dir_add_name()
processing, both of which are slower code and use slower data structure
by git standards, especially when the index is already populated.

Instead, we implement "git add $pathspec..." as:

 - read the index;

 - read_directory() to process untracked, unignored files the current
   way, that is, recursively doing readdir(), filtering them by pathspec
   and excluded(), queueing them via dir_add_name() and finally do
   add_files(); and

 - iterate over the index, filtering them by pathspec, and update only
   the modified/type changed paths but not deleted ones.

And "git add -A" becomes exactly the same as above, modulo:

 - missing $pathspec means "." instead of being an error; and

 - "iterate over the index" part handles deleted ones as well,
   i.e. exactly what the current update_callback() in builtin-add.c does.

In either case, because fill_directory() does not use read_directory() to
read everything in, we need to add an extra logic to iterate over the
index to catch mistyped pathspec.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin-add.c b/builtin-add.c
index 0de516ad95b0c6fe9441a217cfd84b046f568bfe..1834e2d7cd50ec7688ec6c5c7d2c79c8513ed132 100644 (file)
--- a/builtin-add.c
+++ b/builtin-add.c
@@ -18,6 +18,27 @@ static const char * const builtin_add_usage[] = {
 static int patch_interactive = 0, add_interactive = 0;
 static int take_worktree_changes;
 
+static void fill_pathspec_matches(const char **pathspec, char *seen, int specs)
+{
+       int num_unmatched = 0, i;
+
+       /*
+        * Since we are walking the index as if we are warlking the directory,
+        * we have to mark the matched pathspec as seen; otherwise we will
+        * mistakenly think that the user gave a pathspec that did not match
+        * anything.
+        */
+       for (i = 0; i < specs; i++)
+               if (!seen[i])
+                       num_unmatched++;
+       if (!num_unmatched)
+               return;
+       for (i = 0; i < active_nr; i++) {
+               struct cache_entry *ce = active_cache[i];
+               match_pathspec(pathspec, ce->name, ce_namelen(ce), 0, seen);
+       }
+}
+
 static void prune_directory(struct dir_struct *dir, const char **pathspec, int prefix)
 {
        char *seen;
@@ -37,6 +58,7 @@ static void prune_directory(struct dir_struct *dir, const char **pathspec, int p
                        *dst++ = entry;
        }
        dir->nr = dst - dir->entries;
+       fill_pathspec_matches(pathspec, seen, specs);
 
        for (i = 0; i < specs; i++) {
                if (!seen[i] && !file_exists(pathspec[i]))
@@ -201,7 +223,7 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 
        if (addremove && take_worktree_changes)
                die("-A and -u are mutually incompatible");
-       if (addremove && !argc) {
+       if ((addremove || take_worktree_changes) && !argc) {
                static const char *here[2] = { ".", NULL };
                argc = 1;
                argv = here;
@@ -214,7 +236,9 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 
        flags = ((verbose ? ADD_CACHE_VERBOSE : 0) |
                 (show_only ? ADD_CACHE_PRETEND : 0) |
-                (ignore_add_errors ? ADD_CACHE_IGNORE_ERRORS : 0));
+                (ignore_add_errors ? ADD_CACHE_IGNORE_ERRORS : 0) |
+                (!(addremove || take_worktree_changes)
+                 ? ADD_CACHE_IGNORE_REMOVAL : 0));
 
        if (require_pathspec && argc == 0) {
                fprintf(stderr, "Nothing specified, nothing added.\n");
@@ -223,24 +247,19 @@ int cmd_add(int argc, const char **argv, const char *prefix)
        }
        pathspec = get_pathspec(prefix, argv);
 
-       /*
-        * If we are adding new files, we need to scan the working
-        * tree to find the ones that match pathspecs; this needs
-        * to be done before we read the index.
-        */
-       if (add_new_files)
-               fill_directory(&dir, pathspec, ignored_too);
-
        if (read_cache() < 0)
                die("index file corrupt");
 
+       if (add_new_files)
+               /* This picks up the paths that are not tracked */
+               fill_directory(&dir, pathspec, ignored_too);
+
        if (refresh_only) {
                refresh(verbose, pathspec);
                goto finish;
        }
 
-       if (take_worktree_changes || addremove)
-               exit_status |= add_files_to_cache(prefix, pathspec, flags);
+       exit_status |= add_files_to_cache(prefix, pathspec, flags);
 
        if (add_new_files)
                exit_status |= add_files(&dir, flags);