Test and refactor getnextcomp -> path_next_component.

src/eval.c

@@ -12422,7 +12422,7 @@ static void f_resolve(typval_T *argvars, typval_T *rettv)
       p[len - 1] = NUL;       /* the trailing slash breaks readlink() */
     }
 
-    q = getnextcomp(p);
+    q = path_next_component(p);
     if (*q != NUL) {
       /* Separate the first path component in "p", and keep the
        * remainder (beginning with the path separator). */
@@ -12456,7 +12456,7 @@ static void f_resolve(typval_T *argvars, typval_T *rettv)
 
         /* Separate the first path component in the link value and
          * concatenate the remainders. */
-        q = getnextcomp(vim_ispathsep(*buf) ? buf + 1 : buf);
+        q = path_next_component(vim_ispathsep(*buf) ? buf + 1 : buf);
         if (*q != NUL) {
           if (remain == NULL)
             remain = vim_strsave(q - 1);
@@ -12495,7 +12495,7 @@ static void f_resolve(typval_T *argvars, typval_T *rettv)
         break;
 
       /* Append the first path component of "remain" to "p". */
-      q = getnextcomp(remain + 1);
+      q = path_next_component(remain + 1);
       len = q - remain - (*q != NUL);
       cpy = vim_strnsave(p, STRLEN(p) + len);
       if (cpy != NULL) {

src/path.c

@@ -93,15 +93,15 @@ char_u *path_tail_with_seperator(char_u *fname)
   return tail;
 }
 
-/*
- * get the next path component (just after the next path separator).
- */
-char_u *getnextcomp(char_u *fname)
+char_u *path_next_component(char_u *fname)
 {
-  while (*fname && !vim_ispathsep(*fname))
+  assert(fname != NULL);
+  while (*fname != NUL && !vim_ispathsep(*fname)) {
     mb_ptr_adv(fname);
-  if (*fname)
+  }
+  if (*fname != NUL) {
     ++fname;
+  }
   return fname;
 }
 
@@ -1428,7 +1428,7 @@ void simplify_filename(char_u *filename)
       }
     } else {
       ++components;                     /* simple path component */
-      p = getnextcomp(p);
+      p = path_next_component(p);
     }
   } while (*p != NUL);
 }

src/path.h

@@ -33,13 +33,20 @@ char_u *path_tail(char_u *fname);
 ///
 /// Takes care of "c:/" and "//". That means `path_tail_with_seperator("dir///file.txt")`
 /// will return a pointer to `"///file.txt"`.
-/// @param fname A file path.
+/// @param fname A file path. (Must be != NULL.)
 /// @return
 ///   - Pointer to the last path seperator of `fname`, if there is any.
 ///   - `fname` if it contains no path seperator.
 ///   - Never NULL.
 char_u *path_tail_with_seperator(char_u *fname);
 
+/// Get the next path component of a path name.
+///
+/// @param fname A file path. (Must be != NULL.)
+/// @return Pointer to first found path seperator + 1.
+/// An empty string, if `fname` doesn't contain a path seperator, 
+char_u *path_next_component(char_u *fname);
+
 int vim_ispathsep(int c);
 int vim_ispathsep_nocolon(int c);
 int vim_ispathlistsep(int c);
@@ -54,7 +61,6 @@ int gen_expand_wildcards(int num_pat, char_u **pat, int *num_file,
                          char_u ***file,
                          int flags);
 void addfile(garray_T *gap, char_u *f, int flags);
-char_u *getnextcomp(char_u *fname);
 char_u *get_past_head(char_u *path);
 char_u *concat_str(char_u *str1, char_u *str2);
 void add_pathsep(char_u *p);

test/unit/path.moon

@@ -9,6 +9,7 @@ typedef enum file_comparison {
 FileComparison path_full_compare(char_u *s1, char_u *s2, int checkname);
 char_u *path_tail(char_u *fname);
 char_u *path_tail_with_seperator(char_u *fname);
+char_u *path_next_component(char_u *fname);
 ]]
 
 -- import constants parsed by ffi
@@ -85,3 +86,15 @@ describe 'path function', ->
 
     it 'returns the whole file name if there is no seperator', ->
       eq 'file.txt', path_tail_with_seperator 'file.txt'
+
+  describe 'path_next_component', ->
+    path_next_component = (file) ->
+      res = path.path_next_component (to_cstr file)
+      neq NULL, res
+      ffi.string res
+
+    it 'returns', ->
+      eq 'directory/file.txt', path_next_component 'some/directory/file.txt'
+
+    it 'returns empty string if given file contains no seperator', ->
+      eq '', path_next_component 'file.txt'