Shaoxuan Yuan <shaoxuan.yuan02@xxxxxxxxx> writes:
> Before this patch, whenever --sparse is used, `git-grep` utilizes the
> ensure_full_index() method to expand the index and search all the
> entries. Because this method requires walking all the trees and
> constructing the index, it is the slow part within the whole command.
>
> To achieve better performance, this patch uses grep_tree() to search the
> sparse directory entries and get rid of the ensure_full_index() method.
When you encounter a "sparsedir" (i.e. a tree recorded in index),
you should know the path leading to that directory. Even though I no
longer remember the details of the implementations of grep_$where()
which I did long time ago, I think grep_tree() should know how to
pass the leading path down, as that is the most natural way to
implement the recursive behaviour. This patch should be able to
piggyback on that.
> @@ -537,8 +534,26 @@ static int grep_cache(struct grep_opt *opt,
>
> strbuf_setlen(&name, name_base_len);
> strbuf_addstr(&name, ce->name);
> + if (S_ISSPARSEDIR(ce->ce_mode)) {
> + enum object_type type;
> + struct tree_desc tree;
> + void *data;
> + unsigned long size;
> + struct strbuf base = STRBUF_INIT;
> +
> + strbuf_addstr(&base, ce->name);
> +
> + data = read_object_file(&ce->oid, &type, &size);
> + init_tree_desc(&tree, data, size);
>
> + /*
> + * sneak in the ce_mode using check_attr parameter
> + */
> + hit |= grep_tree(opt, pathspec, &tree, &base,
> + base.len, ce->ce_mode);
OK. Instead of inventing a new "base" strbuf, we could reuse
existing name while running the grep_tree() and restore it after it
returns, and I suspect that the end result would be more in line
with how grep_cache() uses that "name" buffer for all the cache
entries. But that is not a correctness issue (it is move about
preventing from making the code worse).
> @@ -598,7 +613,14 @@ static int grep_tree(struct grep_opt *opt, const struct pathspec *pathspec,
> int te_len = tree_entry_len(&entry);
>
> if (match != all_entries_interesting) {
> - strbuf_addstr(&name, base->buf + tn_len);
> + if (S_ISSPARSEDIR(check_attr)) {
> + // object is a sparse directory entry
No // comments, please.
