Re: [GSoC][PATCH v8 20/20] stash: replace all `write-tree` child processes with API calls

> This commit replaces spawning `git write-tree` with API calls.
> 
> Signed-off-by: Paul-Sebastian Ungureanu <ungureanupaulsebastian@gmail.com>
> ---
>  builtin/stash.c | 41 ++++++++++++-----------------------------
>  1 file changed, 12 insertions(+), 29 deletions(-)

> 
> diff --git a/builtin/stash.c b/builtin/stash.c
> index ba5818e24e..dd1084afd4 100644
> --- a/builtin/stash.c
> +++ b/builtin/stash.c
> @@ -910,9 +910,8 @@ static int save_untracked_files(struct stash_info *info, struct strbuf *msg)
>  {
>  	int ret = 0;
>  	struct strbuf untracked_msg = STRBUF_INIT;
> -	struct strbuf out = STRBUF_INIT;
>  	struct child_process cp_upd_index = CHILD_PROCESS_INIT;
> -	struct child_process cp_write_tree = CHILD_PROCESS_INIT;
> +	struct index_state istate = { NULL };
>  
>  	cp_upd_index.git_cmd = 1;
>  	argv_array_pushl(&cp_upd_index.args, "update-index", "-z", "--add",
> @@ -927,15 +926,11 @@ static int save_untracked_files(struct stash_info *info, struct strbuf *msg)
>  		goto done;
>  	}
>  
> -	cp_write_tree.git_cmd = 1;
> -	argv_array_push(&cp_write_tree.args, "write-tree");
> -	argv_array_pushf(&cp_write_tree.env_array, "GIT_INDEX_FILE=%s",
> -			 stash_index_path.buf);
> -	if (pipe_command(&cp_write_tree, NULL, 0, &out, 0,NULL, 0)) {
> +	if (write_index_as_tree(&info->u_tree, &istate, stash_index_path.buf, 0,
> +				NULL)) {
>  		ret = -1;
>  		goto done;
>  	}
> -	get_oid_hex(out.buf, &info->u_tree);
>  
>  	if (commit_tree(untracked_msg.buf, untracked_msg.len,
>  			&info->u_tree, NULL, &info->u_commit, NULL, NULL)) {
> @@ -944,8 +939,8 @@ static int save_untracked_files(struct stash_info *info, struct strbuf *msg)
>  	}
>  
>  done:
> +	discard_index(&istate);
>  	strbuf_release(&untracked_msg);
> -	strbuf_release(&out);
>  	remove_path(stash_index_path.buf);
>  	return ret;
>  }
> @@ -956,11 +951,10 @@ static int stash_patch(struct stash_info *info, struct pathspec ps, int quiet)
>  {
>  	int i;
>  	int ret = 0;
> -	struct strbuf out = STRBUF_INIT;
>  	struct child_process cp_read_tree = CHILD_PROCESS_INIT;
>  	struct child_process cp_add_i = CHILD_PROCESS_INIT;
> -	struct child_process cp_write_tree = CHILD_PROCESS_INIT;
>  	struct child_process cp_diff_tree = CHILD_PROCESS_INIT;
> +	struct index_state istate = { NULL };
>  
>  	remove_path(stash_index_path.buf);
>  
> @@ -985,17 +979,12 @@ static int stash_patch(struct stash_info *info, struct pathspec ps, int quiet)
>  		goto done;
>  	}
>  
> -	cp_write_tree.git_cmd = 1;
> -	argv_array_push(&cp_write_tree.args, "write-tree");
> -	argv_array_pushf(&cp_write_tree.env_array, "GIT_INDEX_FILE=%s",
> -			 stash_index_path.buf);
> -	if (pipe_command(&cp_write_tree, NULL, 0, &out, 0,NULL, 0)) {
> +	if (write_index_as_tree(&info->w_tree, &istate, stash_index_path.buf, 0,
> +				NULL)) {
>  		ret = -1;
>  		goto done;
>  	}
>  
> -	get_oid_hex(out.buf, &info->w_tree);
> -
>  	cp_diff_tree.git_cmd = 1;
>  	argv_array_pushl(&cp_diff_tree.args, "diff-tree", "-p", "HEAD",
>  			 oid_to_hex(&info->w_tree), "--", NULL);
> @@ -1011,7 +1000,7 @@ static int stash_patch(struct stash_info *info, struct pathspec ps, int quiet)
>  	}
>  
>  done:
> -	strbuf_release(&out);
> +	discard_index(&istate);
>  	remove_path(stash_index_path.buf);
>  	return ret;
>  }
> @@ -1020,10 +1009,9 @@ static int stash_working_tree(struct stash_info *info, struct pathspec ps)
>  {
>  	int ret = 0;
>  	struct child_process cp_upd_index = CHILD_PROCESS_INIT;
> -	struct child_process cp_write_tree = CHILD_PROCESS_INIT;
> -	struct strbuf out = STRBUF_INIT;
>  	struct strbuf diff_output = STRBUF_INIT;
>  	struct rev_info rev;
> +	struct index_state istate = { NULL };
>  
>  	set_alternate_index_output(stash_index_path.buf);
>  	if (reset_tree(&info->i_tree, 0, 0)) {
> @@ -1062,20 +1050,15 @@ static int stash_working_tree(struct stash_info *info, struct pathspec ps)
>  		goto done;
>  	}
>  
> -	cp_write_tree.git_cmd = 1;
> -	argv_array_push(&cp_write_tree.args, "write-tree");
> -	argv_array_pushf(&cp_write_tree.env_array, "GIT_INDEX_FILE=%s",
> -			 stash_index_path.buf);
> -	if (pipe_command(&cp_write_tree, NULL, 0, &out, 0,NULL, 0)) {
> +	if (write_index_as_tree(&info->w_tree, &istate, stash_index_path.buf, 0,
> +				NULL)) {
>  		ret = -1;
>  		goto done;
>  	}
>  
> -	get_oid_hex(out.buf, &info->w_tree);
> -
>  done:
> +	discard_index(&istate);
>  	UNLEAK(rev);
> -	strbuf_release(&out);
>  	object_array_clear(&rev.pending);
>  	strbuf_release(&diff_output);
>  	remove_path(stash_index_path.buf);
> -- 
> 2.19.0.rc0.22.gc26283d74e
> 
>