Re: [PATCH v3 03/10] setup: convert setup_git_directory_gently_1 et al. to strbuf

> Convert setup_git_directory_gently_1() and its helper functions
> setup_explicit_git_dir(), setup_discovered_git_dir() and
> setup_bare_git_dir() to use a struct strbuf to hold the current working
> directory.  Replacing the PATH_MAX-sized buffer used before removes a
> path length limition on some file systems.  The functions are converted
> all in one go because they all read and write the variable cwd.
> 
> Signed-off-by: Rene Scharfe <l.s.r@web.de>
> ---
>  setup.c | 85 +++++++++++++++++++++++++++++++++--------------------------------
>  1 file changed, 43 insertions(+), 42 deletions(-)
> 
> diff --git a/setup.c b/setup.c
> index 0a22f8b..c8b8a97 100644
> --- a/setup.c
> +++ b/setup.c
> @@ -387,7 +387,7 @@ const char *read_gitfile(const char *path)
>  }
>  
>  static const char *setup_explicit_git_dir(const char *gitdirenv,
> -					  char *cwd, int len,
> +					  struct strbuf *cwd,
>  					  int *nongit_ok)
>  {
>  	const char *work_tree_env = getenv(GIT_WORK_TREE_ENVIRONMENT);
> @@ -441,7 +441,7 @@ static const char *setup_explicit_git_dir(const char *gitdirenv,
>  				die_errno("Could not chdir to '%s'", git_work_tree_cfg);
>  			if (!getcwd(core_worktree, PATH_MAX))
>  				die_errno("Could not get directory '%s'", git_work_tree_cfg);
> -			if (chdir(cwd))
> +			if (chdir(cwd->buf))
>  				die_errno("Could not come back to cwd");
>  			set_git_work_tree(core_worktree);
>  		}
> @@ -459,21 +459,20 @@ static const char *setup_explicit_git_dir(const char *gitdirenv,
>  	worktree = get_git_work_tree();
>  
>  	/* both get_git_work_tree() and cwd are already normalized */
> -	if (!strcmp(cwd, worktree)) { /* cwd == worktree */
> +	if (!strcmp(cwd->buf, worktree)) { /* cwd == worktree */
>  		set_git_dir(gitdirenv);
>  		free(gitfile);
>  		return NULL;
>  	}
>  
> -	offset = dir_inside_of(cwd, worktree);
> +	offset = dir_inside_of(cwd->buf, worktree);
>  	if (offset >= 0) {	/* cwd inside worktree? */
>  		set_git_dir(real_path(gitdirenv));
>  		if (chdir(worktree))
>  			die_errno("Could not chdir to '%s'", worktree);
> -		cwd[len++] = '/';
> -		cwd[len] = '\0';
> +		strbuf_addch(cwd, '/');
>  		free(gitfile);
> -		return cwd + offset;
> +		return cwd->buf + offset;
>  	}
>  
>  	/* cwd outside worktree */
> @@ -483,7 +482,7 @@ static const char *setup_explicit_git_dir(const char *gitdirenv,
>  }
>  
>  static const char *setup_discovered_git_dir(const char *gitdir,
> -					    char *cwd, int offset, int len,
> +					    struct strbuf *cwd, int offset,
>  					    int *nongit_ok)
>  {
>  	if (check_repository_format_gently(gitdir, nongit_ok))
> @@ -491,17 +490,17 @@ static const char *setup_discovered_git_dir(const char *gitdir,
>  
>  	/* --work-tree is set without --git-dir; use discovered one */
>  	if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
> -		if (offset != len && !is_absolute_path(gitdir))
> +		if (offset != cwd->len && !is_absolute_path(gitdir))
>  			gitdir = xstrdup(real_path(gitdir));
> -		if (chdir(cwd))
> +		if (chdir(cwd->buf))
>  			die_errno("Could not come back to cwd");
> -		return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
> +		return setup_explicit_git_dir(gitdir, cwd, nongit_ok);
>  	}
>  
>  	/* #16.2, #17.2, #20.2, #21.2, #24, #25, #28, #29 (see t1510) */
>  	if (is_bare_repository_cfg > 0) {
> -		set_git_dir(offset == len ? gitdir : real_path(gitdir));
> -		if (chdir(cwd))
> +		set_git_dir(offset == cwd->len ? gitdir : real_path(gitdir));
> +		if (chdir(cwd->buf))
>  			die_errno("Could not come back to cwd");
>  		return NULL;
>  	}
> @@ -512,18 +511,18 @@ static const char *setup_discovered_git_dir(const char *gitdir,
>  		set_git_dir(gitdir);
>  	inside_git_dir = 0;
>  	inside_work_tree = 1;
> -	if (offset == len)
> +	if (offset == cwd->len)
>  		return NULL;
>  
>  	/* Make "offset" point to past the '/', and add a '/' at the end */
>  	offset++;
> -	cwd[len++] = '/';
> -	cwd[len] = 0;
> -	return cwd + offset;
> +	strbuf_addch(cwd, '/');
> +	return cwd->buf + offset;
>  }
>  
>  /* #16.1, #17.1, #20.1, #21.1, #22.1 (see t1510) */
> -static const char *setup_bare_git_dir(char *cwd, int offset, int len, int *nongit_ok)
> +static const char *setup_bare_git_dir(struct strbuf *cwd, int offset,
> +				      int *nongit_ok)
>  {
>  	int root_len;
>  
> @@ -536,20 +535,20 @@ static const char *setup_bare_git_dir(char *cwd, int offset, int len, int *nongi
>  	if (getenv(GIT_WORK_TREE_ENVIRONMENT) || git_work_tree_cfg) {
>  		const char *gitdir;
>  
> -		gitdir = offset == len ? "." : xmemdupz(cwd, offset);
> -		if (chdir(cwd))
> +		gitdir = offset == cwd->len ? "." : xmemdupz(cwd->buf, offset);
> +		if (chdir(cwd->buf))
>  			die_errno("Could not come back to cwd");
> -		return setup_explicit_git_dir(gitdir, cwd, len, nongit_ok);
> +		return setup_explicit_git_dir(gitdir, cwd, nongit_ok);
>  	}
>  
>  	inside_git_dir = 1;
>  	inside_work_tree = 0;
> -	if (offset != len) {
> -		if (chdir(cwd))
> +	if (offset != cwd->len) {
> +		if (chdir(cwd->buf))
>  			die_errno("Cannot come back to cwd");
> -		root_len = offset_1st_component(cwd);
> -		cwd[offset > root_len ? offset : root_len] = '\0';
> -		set_git_dir(cwd);
> +		root_len = offset_1st_component(cwd->buf);
> +		strbuf_setlen(cwd, offset > root_len ? offset : root_len);
> +		set_git_dir(cwd->buf);
>  	}
>  	else
>  		set_git_dir(".");
> @@ -617,10 +616,10 @@ static const char *setup_git_directory_gently_1(int *nongit_ok)
>  {
>  	const char *env_ceiling_dirs = getenv(CEILING_DIRECTORIES_ENVIRONMENT);
>  	struct string_list ceiling_dirs = STRING_LIST_INIT_DUP;
> -	static char cwd[PATH_MAX + 1];
> +	static struct strbuf cwd = STRBUF_INIT;