Test and refactor shorten_fname and shorten_fname1

Rename `shorten_fname` -> `path_shorten_fname`
Rename `shorten_fname1` -> `path_shorten_fname_if_possible`

src/buffer.c

@@ -4255,7 +4255,7 @@ int read_viminfo_bufferlist(vir_T *virp, int writing)
     /* Expand "~/" in the file name at "line + 1" to a full path.
      * Then try shortening it by comparing with the current directory */
     expand_env(xline, NameBuff, MAXPATHL);
-    sfname = shorten_fname1(NameBuff);
+    sfname = path_shorten_fname_if_possible(NameBuff);
 
     buf = buflist_new(NameBuff, sfname, (linenr_T)0, BLN_LISTED);
     if (buf != NULL) {          /* just in case... */

src/eval.c

@@ -19553,7 +19553,7 @@ repeat:
     if (p != NULL) {
       if (c == '.') {
         os_dirname(dirname, MAXPATHL);
-        s = shorten_fname(p, dirname);
+        s = path_shorten_fname(p, dirname);
         if (s != NULL) {
           *fnamep = s;
           if (pbuf != NULL) {

src/ex_docmd.c

@@ -7965,7 +7965,7 @@ eval_vars (
             "E495: no autocommand file name to substitute for \"<afile>\"");
         return NULL;
       }
-      result = shorten_fname1(result);
+      result = path_shorten_fname_if_possible(result);
       break;
 
     case SPEC_ABUF:             /* buffer number for autocommand */

src/file_search.c

@@ -869,7 +869,7 @@ char_u *vim_findfile(void *search_ctx_arg)
                   simplify_filename(file_path);
                 if (os_dirname(ff_expand_buffer, MAXPATHL)
                     == OK) {
-                  p = shorten_fname(file_path,
+                  p = path_shorten_fname(file_path,
                       ff_expand_buffer);
                   if (p != NULL)
                     STRMOVE(file_path, p);

src/fileio.c

@@ -4654,7 +4654,7 @@ void shorten_fnames(int force)
             || path_is_absolute_path(buf->b_sfname))) {
       vim_free(buf->b_sfname);
       buf->b_sfname = NULL;
-      p = shorten_fname(buf->b_ffname, dirname);
+      p = path_shorten_fname(buf->b_ffname, dirname);
       if (p != NULL) {
         buf->b_sfname = vim_strsave(p);
         buf->b_fname = buf->b_sfname;

src/mark.c

@@ -482,7 +482,7 @@ static void fname2fnum(xfmark_T *fm)
 
     /* Try to shorten the file name. */
     os_dirname(IObuff, IOSIZE);
-    p = shorten_fname(NameBuff, IObuff);
+    p = path_shorten_fname(NameBuff, IObuff);
 
     /* buflist_new() will call fmarks_check_names() */
     (void)buflist_new(NameBuff, p, (linenr_T)1, 0);

src/path.c

@@ -796,7 +796,7 @@ static void uniquefy_paths(garray_T *gap, char_u *pattern)
        *	    /file.txt		  /		/file.txt
        *	    c:\file.txt		  c:\		.\file.txt
        */
-      short_name = shorten_fname(path, curdir);
+      short_name = path_shorten_fname(path, curdir);
       if (short_name != NULL && short_name > path + 1
           ) {
         STRCPY(path, ".");
@@ -817,7 +817,7 @@ static void uniquefy_paths(garray_T *gap, char_u *pattern)
 
     /* If the {filename} is not unique, change it to ./{filename}.
      * Else reduce it to {filename} */
-    short_name = shorten_fname(path, curdir);
+    short_name = path_shorten_fname(path, curdir);
     if (short_name == NULL)
       short_name = path;
     if (is_unique(short_name, gap, i)) {
@@ -1708,54 +1708,37 @@ int flags;                      /* EW_* flags */
 }
 #endif
 
-#if defined(FEAT_VIMINFO) || defined(FEAT_BROWSE) || \
-  defined(FEAT_QUICKFIX) || defined(FEAT_AUTOCMD) || defined(PROTO)
-/*
- * Try to find a shortname by comparing the fullname with the current
- * directory.
- * Returns "full_path" or pointer into "full_path" if shortened.
- */
-char_u *shorten_fname1(char_u *full_path)
+char_u *path_shorten_fname_if_possible(char_u *full_path)
 {
-  char_u      *dirname;
-  char_u      *p = full_path;
+  char_u *dirname = xmalloc(MAXPATHL);
+  char_u *p = full_path;
 
-  dirname = alloc(MAXPATHL);
   if (os_dirname(dirname, MAXPATHL) == OK) {
-    p = shorten_fname(full_path, dirname);
-    if (p == NULL || *p == NUL)
+    p = path_shorten_fname(full_path, dirname);
+    if (p == NULL || *p == NUL) {
       p = full_path;
+    }
   }
   vim_free(dirname);
   return p;
 }
-#endif
 
-/*
- * Try to find a shortname by comparing the fullname with the current
- * directory.
- * Returns NULL if not shorter name possible, pointer into "full_path"
- * otherwise.
- */
-char_u *shorten_fname(char_u *full_path, char_u *dir_name)
+char_u *path_shorten_fname(char_u *full_path, char_u *dir_name)
 {
-  int len;
-  char_u      *p;
-
-  if (full_path == NULL)
+  if (full_path == NULL) {
     return NULL;
-  len = (int)STRLEN(dir_name);
-  if (fnamencmp(dir_name, full_path, len) == 0) {
-    p = full_path + len;
-    {
-      if (vim_ispathsep(*p))
-        ++p;
-      else
-        p = NULL;
-    }
-  } else
-    p = NULL;
-  return p;
+  }
+
+  assert(dir_name != NULL);
+  size_t len = strlen((char *)dir_name);
+  char_u *p = full_path + len;
+
+  if (fnamencmp(dir_name, full_path, len) != 0
+      || !vim_ispathsep(*p)) {
+    return NULL;
+  }
+
+  return p + 1;
 }
 
 /*

src/path.h

@@ -83,8 +83,26 @@ int after_pathsep(char_u *b, char_u *p);
 int same_directory(char_u *f1, char_u *f2);
 int pathcmp(const char *p, const char *q, int maxlen);
 int mch_expandpath(garray_T *gap, char_u *path, int flags);
-char_u *shorten_fname1(char_u *full_path);
-char_u *shorten_fname(char_u *full_path, char_u *dir_name);
+
+/// Try to find a shortname by comparing the fullname with the current
+/// directory.
+///
+/// @param full_path The full path of the file.
+/// @return
+///   - Pointer into `full_path` if shortened.
+///   - `full_path` unchanged if no shorter name is possible.
+///   - NULL if `full_path` is NULL.
+char_u *path_shorten_fname_if_possible(char_u *full_path);
+
+/// Try to find a shortname by comparing the fullname with `dir_name`.
+///
+/// @param full_path The full path of the file.
+/// @param dir_name The directory to shorten relative to.
+/// @return
+///   - Pointer into `full_path` if shortened.
+///   - NULL if no shorter name is possible.
+char_u *path_shorten_fname(char_u *full_path, char_u *dir_name);
+
 int expand_wildcards_eval(char_u **pat, int *num_file, char_u ***file,
                           int flags);
 int expand_wildcards(int num_pat, char_u **pat, int *num_file, char_u *

src/quickfix.c

@@ -2859,7 +2859,7 @@ void ex_vimgrep(exarg_T *eap)
 
   seconds = (time_t)0;
   for (fi = 0; fi < fcount && !got_int && tomatch > 0; ++fi) {
-    fname = shorten_fname1(fnames[fi]);
+    fname = path_shorten_fname_if_possible(fnames[fi]);
     if (time(NULL) > seconds) {
       /* Display the file name every second or so, show the user we are
        * working on it. */

test/unit/path.moon

@@ -92,6 +92,48 @@ describe 'path function', ->
     it 'returns empty string if given file contains no seperator', ->
       eq '', path_next_component 'file.txt'
 
+  describe 'path_shorten_fname', ->
+    it 'returns NULL if `full_path` is NULL', ->
+      dir = to_cstr 'some/directory/file.txt'
+      eq NULL, (path.path_shorten_fname NULL, dir)
+
+    it 'returns NULL if the path and dir does not match', ->
+      dir = to_cstr 'not/the/same'
+      full = to_cstr 'as/this.txt'
+      eq NULL, (path.path_shorten_fname full, dir)
+
+    it 'returns NULL if the path is not separated properly', ->
+      dir = to_cstr 'some/very/long/'
+      full = to_cstr 'some/very/long/directory/file.txt'
+      eq NULL, (path.path_shorten_fname full, dir)
+
+    it 'shortens the filename if `dir_name` is the start of `full_path`', ->
+      full = to_cstr 'some/very/long/directory/file.txt'
+      dir = to_cstr 'some/very/long'
+      eq 'directory/file.txt', (ffi.string path.path_shorten_fname full, dir)
+
+describe 'path_shorten_fname_if_possible', ->
+  before_each ->
+      lfs.mkdir 'ut_directory'
+  after_each ->
+      lfs.chdir '..'
+      lfs.rmdir 'ut_directory'
+
+  describe 'path_shorten_fname_if_possible', ->
+    it 'returns shortened path if possible', ->
+      lfs.chdir 'ut_directory'
+      full = to_cstr lfs.currentdir! .. '/subdir/file.txt'
+      eq 'subdir/file.txt', (ffi.string path.path_shorten_fname_if_possible full)
+
+    it 'returns `full_path` if a shorter version is not possible', ->
+      old = lfs.currentdir!
+      lfs.chdir 'ut_directory'
+      full = old .. '/subdir/file.txt'
+      eq full, (ffi.string path.path_shorten_fname_if_possible to_cstr full)
+
+    it 'returns NULL if `full_path` is NULL', ->
+      eq NULL, (path.path_shorten_fname_if_possible NULL)
+
 describe 'more path function', ->
   setup ->
     lfs.mkdir 'unit-test-directory'