Go back to simpler chdir_arg API

* src/misc.c (add_wd, ensure_wd): New functions, replacing ...
(grow_wd): .. this function, for clarity.  All uses changed.
(chdir_arg): Omit 2nd arg, to keep callers simpler.
All uses changed.  Instead of being recursive, be iterative;
this is part of the simplification.

src/common.h

@@ -782,7 +782,7 @@ idx_t blocking_write (int fd, void const *buf, idx_t count);
 enum { BADFD = AT_FDCWD == -1 ? -2 : -1 };
 
 extern idx_t chdir_current;
-idx_t chdir_arg (char const *dir, bool one_top_level);
+idx_t chdir_arg (char const *dir);
 void chdir_do (idx_t dir, bool create);
 struct chdir_id { int err; dev_t st_dev; ino_t st_ino; } chdir_id (void);
 struct fdbase fdbase (char const *);

src/misc.c

@@ -1015,65 +1015,69 @@ chdir_count (void)
   return count;
 }
 
-/* Grow the WD table by at least one entry.  */
+/* Add DIR to the WD table.  If one_top_level_dir, add that too.
+   There must already be room.
+   DFD is either AT_FDWD for the initial "." entry,
+   or 0 meaning the file descriptor is not open yet.  */
 static void
-grow_wd (void)
+add_wd (char const *dir, int dfd)
 {
-  wd = xpalloc (wd, &wd_alloc, wd_alloc ? 1 : 2, -1, sizeof *wd);
+  wd[wd_count].name = dir;
+  wd[wd_count].abspath = NULL;
+  wd[wd_count].fd = dfd;
+  wd[wd_count].id.err = -1;
+  wd[wd_count].one_top_level = false;
+  wd_count++;
 
-  if (! wd_count)
+  if (one_top_level_dir)
     {
-      wd[wd_count].name = ".";
+      wd[wd_count].name = one_top_level_dir;
       wd[wd_count].abspath = NULL;
-      wd[wd_count].fd = AT_FDCWD;
+      wd[wd_count].fd = 0;
       wd[wd_count].id.err = -1;
-      wd[wd_count].one_top_level = false;
+      wd[wd_count].one_top_level = true;
       wd_count++;
-      if (one_top_level_dir)
-	{
-	  wd[wd_count].name = one_top_level_dir;
-	  wd[wd_count].abspath = NULL;
-	  wd[wd_count].fd = 0;
-	  wd[wd_count].id.err = -1;
-	  wd[wd_count].one_top_level = true;
-	  wd_count++;
-	}
+    }
+}
+
+/* Ensure that WD exists, with an initial "." entry.  */
+static void
+ensure_wd (void)
+{
+  if (!wd)
+    {
+      /* This must be at least 1 + !!top_level_dir.  Make it 4, to lessen
+	 reallocation effort when -C and --one-top-level are both used.  */
+      int n_incr_min = 4;
+
+      wd = xpalloc (NULL, &wd_alloc, n_incr_min, -1, sizeof *wd);
+      add_wd (".", AT_FDCWD);
     }
 }
 
 /* DIR is the operand of a -C option; add it to vector of chdir targets,
-   and return the index of its location.  */
+   and return the index of its location.  If --one-top-level-dir, add
+   two targets to the vector.  However, if DIR is "." or an equivalent,
+   just reuse the last item in the vector.  */
 idx_t
-chdir_arg (char const *dir, bool one_top_level)
+chdir_arg (char const *dir)
 {
-  if (one_top_level)
-    chdir_arg (dir, false);
-  if (wd_count == wd_alloc)
-    grow_wd ();
+  ensure_wd ();
 
   /* Optimize the common special case of the working directory,
      or the working directory as a prefix.  */
   if (dir[0])
     {
       dir += dotslashlen (dir);
-      if (! dir[dir[0] == '.'])
-	{
-	  if (wd[wd_count - 1].one_top_level == one_top_level)
-	    return wd_count - 1;
-	  else
-	    return wd_count - 2;
-	}
+      if (!dir[dir[0] == '.'])
+	return wd_count - 1;
     }
 
-  if (one_top_level)
-    dir = one_top_level_dir;
-
-  wd[wd_count].name = dir;
-  wd[wd_count].abspath = NULL;
-  wd[wd_count].fd = 0;
-  wd[wd_count].id.err = -1;
-  wd[wd_count].one_top_level = one_top_level;
-  return wd_count++;
+  ptrdiff_t shortage = 1 + !!one_top_level_dir - (wd_alloc - wd_count);
+  if (0 < shortage)
+    wd = xpalloc (wd, &wd_alloc, shortage, -1, sizeof *wd);
+  add_wd (dir, 0);
+  return wd_count - 1;
 }
 
 /* Index of current directory.  */
@@ -1202,8 +1206,7 @@ chdir_do (idx_t i, bool create)
 struct chdir_id
 chdir_id (void)
 {
-  if (!wd)
-    grow_wd ();
+  ensure_wd ();
 
   struct wd *curr = &wd[chdir_current];
   if (curr->id.err < 0)
@@ -1418,8 +1421,8 @@ transform_top_level (const char *name)
 /* Return the absolute path that represents the working
    directory referenced by IDX.
 
-   If wd is empty, then there were no -C options given, and
-   chdir_args() has never been called, so we simply return the
+   If wd is empty, then no -C options were given, and
+   chdir_arg has never been called, so simply return the
    process's actual cwd.  (Note that in this case IDX is ignored,
    since it should always be 0.) */
 static const char *

src/names.c

@@ -875,7 +875,7 @@ static idx_t name_buffer_length; /* allocated length of name_buffer */
 void
 name_init (void)
 {
-  chdir_do (chdir_arg (".", !!one_top_level_dir), false);
+  chdir_do (chdir_arg ("."), false);
   name_list_adjust ();
 }
 
@@ -1119,8 +1119,7 @@ name_next_elt (bool change_dirs)
 	case NELT_CHDIR:
 	  if (change_dirs)
 	    {
-	      chdir_do (chdir_arg (xstrdup (ep->v.name), !!one_top_level_dir),
-			false);
+	      chdir_do (chdir_arg (xstrdup (ep->v.name)), false);
 	      name_list_advance ();
 	      break;
 	    }
@@ -1183,7 +1182,7 @@ name_gather (void)
       static idx_t change_dir;
 
       while ((ep = name_next_elt (false)) && ep->type == NELT_CHDIR)
-	change_dir = chdir_arg (xstrdup (ep->v.name), !!one_top_level_dir);
+	change_dir = chdir_arg (xstrdup (ep->v.name));
 
       if (ep)
 	{
@@ -1212,7 +1211,7 @@ name_gather (void)
 	{
 	  idx_t change_dir0 = change_dir;
 	  while ((ep = name_next_elt (false)) && ep->type == NELT_CHDIR)
-	    change_dir = chdir_arg (xstrdup (ep->v.name), !!one_top_level_dir);
+	    change_dir = chdir_arg (xstrdup (ep->v.name));
 
 	  if (ep)
 	    addname (ep->v.name, change_dir, true, NULL);