Re: [RFC v3 1/8] Convert substitute_path_component to C++

[Sergio Durigan Junior <sergiodj@redhat.com>]

On Thursday, March 16 2017, Philipp Rudo wrote:

> Simplify the code of utils.c:substiute_path_component by converting it to C++.

Thanks for the patch, Philipp.  Just a minor nit.

> gdb/ChangeLog:
>
> 	* utils.c (substitute_path_component): Convert to C++.
> 	* utils.h (substitute_path_componetn): Adjust declatation.
> 	* auto-load.c (auto_load_expand_dir_vars): Adjust.
> ---
>  gdb/auto-load.c | 18 +++++++++---------
>  gdb/utils.c     | 50 ++++++++++++++------------------------------------
>  gdb/utils.h     |  9 +++++++--
>  3 files changed, 30 insertions(+), 47 deletions(-)
>
> diff --git a/gdb/auto-load.c b/gdb/auto-load.c
> index 56914c8..c84fee1 100644
> --- a/gdb/auto-load.c
> +++ b/gdb/auto-load.c
> @@ -40,6 +40,7 @@
>  #include "filestuff.h"
>  #include "extension.h"
>  #include "gdb/section-scripts.h"
> +#include <string>
>  
>  /* The section to look in for auto-loaded scripts (in file formats that
>     support sections).
> @@ -175,21 +176,20 @@ static VEC (char_ptr) *auto_load_safe_path_vec;
>     this vector must be freed by free_char_ptr_vec by the caller.  */
>  
>  static VEC (char_ptr) *
> -auto_load_expand_dir_vars (const char *string)
> +auto_load_expand_dir_vars (std::string orig)
>  {
>    VEC (char_ptr) *dir_vec;
> -  char *s;
> +  std::string str = orig;
>  
> -  s = xstrdup (string);
> -  substitute_path_component (&s, "$datadir", gdb_datadir);
> -  substitute_path_component (&s, "$debugdir", debug_file_directory);
> +  substitute_path_component (str, "$datadir", gdb_datadir);
> +  substitute_path_component (str, "$debugdir", debug_file_directory);
>  
> -  if (debug_auto_load && strcmp (s, string) != 0)
> +  if (debug_auto_load && str.compare (orig) != 0)
>      fprintf_unfiltered (gdb_stdlog,
> -			_("auto-load: Expanded $-variables to \"%s\".\n"), s);
> +			_("auto-load: Expanded $-variables to \"%s\".\n"),
> +			str.c_str ());
>  
> -  dir_vec = dirnames_to_char_ptr_vec (s);
> -  xfree(s);
> +  dir_vec = dirnames_to_char_ptr_vec (str.c_str ());
>  
>    return dir_vec;
>  }
> diff --git a/gdb/utils.c b/gdb/utils.c
> index 27021a1..bef619a 100644
> --- a/gdb/utils.c
> +++ b/gdb/utils.c
> @@ -66,6 +66,8 @@
>  #include "interps.h"
>  #include "gdb_regex.h"
>  
> +#include <string>
> +
>  #if !HAVE_DECL_MALLOC
>  extern PTR malloc ();		/* ARI: PTR */
>  #endif
> @@ -3158,49 +3160,25 @@ make_cleanup_free_char_ptr_vec (VEC (char_ptr) *char_ptr_vec)
>    return make_cleanup (do_free_char_ptr_vec, char_ptr_vec);
>  }
>  
> -/* Substitute all occurences of string FROM by string TO in *STRINGP.  *STRINGP
> -   must come from xrealloc-compatible allocator and it may be updated.  FROM
> -   needs to be delimited by IS_DIR_SEPARATOR or DIRNAME_SEPARATOR (or be
> -   located at the start or end of *STRINGP.  */
> +/* See utils.h.  */
>  
>  void
> -substitute_path_component (char **stringp, const char *from, const char *to)
> +substitute_path_component (std::string &str, const std::string &from,
> +			   const std::string &to)
>  {
> -  char *string = *stringp, *s;
> -  const size_t from_len = strlen (from);
> -  const size_t to_len = strlen (to);
> -
> -  for (s = string;;)
> +  for (size_t pos = str.find (from); pos != std::string::npos;
> +       pos = str.find (from, pos + 1))
>      {
> -      s = strstr (s, from);
> -      if (s == NULL)
> -	break;
> -
> -      if ((s == string || IS_DIR_SEPARATOR (s[-1])
> -	   || s[-1] == DIRNAME_SEPARATOR)
> -          && (s[from_len] == '\0' || IS_DIR_SEPARATOR (s[from_len])
> -	      || s[from_len] == DIRNAME_SEPARATOR))
> +      char start, end;

Missing blank like between the declaration of the variables and the
assignment.

> +      start = str[pos - 1];
> +      end = str[pos + from.length ()];
> +      if ((pos == 0 || IS_DIR_SEPARATOR (start) || start == DIRNAME_SEPARATOR)
> +	  && (end == '\0' || IS_DIR_SEPARATOR (end)
> +	      || end == DIRNAME_SEPARATOR))
>  	{
> -	  char *string_new;
> -
> -	  string_new
> -	    = (char *) xrealloc (string, (strlen (string) + to_len + 1));
> -
> -	  /* Relocate the current S pointer.  */
> -	  s = s - string + string_new;
> -	  string = string_new;
> -
> -	  /* Replace from by to.  */
> -	  memmove (&s[to_len], &s[from_len], strlen (&s[from_len]) + 1);
> -	  memcpy (s, to, to_len);
> -
> -	  s += to_len;
> +	  str.replace (pos, from.length (), to);
>  	}
> -      else
> -	s++;
>      }
> -
> -  *stringp = string;
>  }
>  
>  #ifdef HAVE_WAITPID
> diff --git a/gdb/utils.h b/gdb/utils.h
> index f138702..d32114e 100644
> --- a/gdb/utils.h
> +++ b/gdb/utils.h
> @@ -132,8 +132,13 @@ extern char *gdb_abspath (const char *);
>  extern int gdb_filename_fnmatch (const char *pattern, const char *string,
>  				 int flags);
>  
> -extern void substitute_path_component (char **stringp, const char *from,
> -				       const char *to);
> +/* Substitute all occurences of string FROM by string TO in STR.  FROM
> +   needs to be delimited by IS_DIR_SEPARATOR or DIRNAME_SEPARATOR (or be
> +   located at the start or end of STR).  */
> +
> +extern void substitute_path_component (std::string &str,
> +				       const std::string &from,
> +				       const std::string &to);
>  
>  char *ldirname (const char *filename);
>  
> -- 
> 2.8.4

Other than that, LGTM.

Thanks,

-- 
Sergio
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