Replace ga->ga_len > 0 checks with !GA_EMPTY(ga)

Used Coccinelle to perform the changes

```diff
@@
expression E;
@@

<...
(
- E.ga_len > 0
+ !GA_EMPTY(&E)
|
- E->ga_len > 0
+ !GA_EMPTY(E)
)
...>
```

`spatch --in-place --sp-file ga_empty.cocci <C_FILE>`

src/nvim/eval.c

@@ -10766,7 +10766,7 @@ static garray_T ga_userinput = {0, 0, sizeof(tasave_T), 4, NULL};
  */
 static void f_inputrestore(typval_T *argvars, typval_T *rettv)
 {
-  if (ga_userinput.ga_len > 0) {
+  if (!GA_EMPTY(&ga_userinput)) {
     --ga_userinput.ga_len;
     restore_typeahead((tasave_T *)(ga_userinput.ga_data)
         + ga_userinput.ga_len);

src/nvim/ex_cmds2.c

@@ -580,7 +580,7 @@ void ex_breakdel(exarg_T *eap)
   if (todel < 0)
     EMSG2(_("E161: Breakpoint not found: %s"), eap->arg);
   else {
-    while (gap->ga_len > 0) {
+    while (!GA_EMPTY(gap)) {
       free(DEBUGGY(gap, todel).dbg_name);
       vim_regfree(DEBUGGY(gap, todel).dbg_prog);
       --gap->ga_len;

src/nvim/ex_docmd.c

@@ -872,7 +872,7 @@ int flags;
      * When not inside any ":while" loop, clear remembered lines.
      */
     if (cstack.cs_looplevel == 0) {
-      if (lines_ga.ga_len > 0) {
+      if (!GA_EMPTY(&lines_ga)) {
         sourcing_lnum =
           ((wcmd_T *)lines_ga.ga_data)[lines_ga.ga_len - 1].lnum;
         free_cmdlines(&lines_ga);
@@ -1188,7 +1188,7 @@ static void store_loop_line(garray_T *gap, char_u *line)
  */
 static void free_cmdlines(garray_T *gap)
 {
-  while (gap->ga_len > 0) {
+  while (!GA_EMPTY(gap)) {
     free(((wcmd_T *)(gap->ga_data))[gap->ga_len - 1].line);
     --gap->ga_len;
   }

src/nvim/ex_getln.c

@@ -1831,7 +1831,7 @@ getexmodeline (
 
       if (c1 == BS || c1 == K_BS
           || c1 == DEL || c1 == K_DEL || c1 == K_KDEL) {
-        if (line_ga.ga_len > 0) {
+        if (!GA_EMPTY(&line_ga)) {
           --line_ga.ga_len;
           goto redraw;
         }
@@ -1940,7 +1940,7 @@ redraw:
 
     /* We are done when a NL is entered, but not when it comes after an
      * odd number of backslashes, that results in a NUL. */
-    if (line_ga.ga_len > 0 && pend[-1] == '\n') {
+    if (!GA_EMPTY(&line_ga) && pend[-1] == '\n') {
       int bcount = 0;
 
       while (line_ga.ga_len - 2 >= bcount && pend[-2 - bcount] == '\\')

src/nvim/fold.c

@@ -138,7 +138,7 @@ int hasAnyFolding(win_T *win)
 {
   /* very simple now, but can become more complex later */
   return win->w_p_fen
-         && (!foldmethodIsManual(win) || win->w_folds.ga_len > 0);
+         && (!foldmethodIsManual(win) || !GA_EMPTY(&win->w_folds));
 }
 
 /* hasFolding() {{{2 */
@@ -2655,7 +2655,7 @@ static void foldMerge(fold_T *fp1, garray_T *gap, fold_T *fp2)
     foldMerge(fp3, gap2, fp4);
 
   /* Move nested folds in fp2 to the end of fp1. */
-  if (gap2->ga_len > 0) {
+  if (!GA_EMPTY(gap2)) {
     ga_grow(gap1, gap2->ga_len);
     for (idx = 0; idx < gap2->ga_len; ++idx) {
       ((fold_T *)gap1->ga_data)[gap1->ga_len]
@@ -2982,7 +2982,7 @@ static int put_foldopen_recurse(FILE *fd, win_T *wp, garray_T *gap, linenr_T off
   fp = (fold_T *)gap->ga_data;
   for (i = 0; i < gap->ga_len; i++) {
     if (fp->fd_flags != FD_LEVEL) {
-      if (fp->fd_nested.ga_len > 0) {
+      if (!GA_EMPTY(&fp->fd_nested)) {
         /* open nested folds while this fold is open */
         if (fprintf(fd, "%" PRId64, (int64_t)(fp->fd_top + off)) < 0
             || put_eol(fd) == FAIL

src/nvim/garray.c

@@ -185,7 +185,7 @@ void ga_append(garray_T *gap, char c)
 void append_ga_line(garray_T *gap)
 {
   // Remove trailing CR.
-  if ((gap->ga_len > 0)
+  if (!GA_EMPTY(gap)
       && !curbuf->b_p_bin
       && (((char_u *)gap->ga_data)[gap->ga_len - 1] == CAR)) {
     gap->ga_len--;

src/nvim/garray.h

@@ -16,6 +16,8 @@ typedef struct growarray {
 
 #define GA_EMPTY_INIT_VALUE { 0, 0, 0, 0, NULL }
 
+#define GA_EMPTY(ga_ptr) ((ga_ptr)->ga_len <= 0)
+
 void ga_clear(garray_T *gap);
 void ga_clear_strings(garray_T *gap);
 void ga_init(garray_T *gap, int itemsize, int growsize);

src/nvim/hardcopy.c

@@ -1513,7 +1513,7 @@ static void prt_def_var(char *name, double value, int prec)
 
 static void prt_flush_buffer(void)
 {
-  if (prt_ps_buffer.ga_len > 0) {
+  if (!GA_EMPTY(&prt_ps_buffer)) {
     /* Any background color must be drawn first */
     if (prt_do_bgcol && (prt_new_bgcol != PRCOLOR_WHITE)) {
       int r, g, b;

src/nvim/option.c

@@ -1964,7 +1964,7 @@ void set_init_1(void)
         /* First time count the NUL, otherwise count the ','. */
         len = (int)STRLEN(p) + 3;
         ga_grow(&ga, len);
-        if (ga.ga_len > 0)
+        if (!GA_EMPTY(&ga))
           STRCAT(ga.ga_data, ",");
         STRCAT(ga.ga_data, p);
         add_pathsep(ga.ga_data);

src/nvim/os/shell.c

@@ -229,7 +229,7 @@ int os_call_shell(char_u *cmd, ShellOpts opts, char_u *extra_shell_arg)
   }
 
   if (opts & kShellOptRead) {
-    if (pdata.ga.ga_len > 0) {
+    if (!GA_EMPTY(&pdata.ga)) {
       // If there's an unfinished line in the growable array, append it now.
       append_ga_line(&pdata.ga);
       // remember that the NL was missing

src/nvim/path.c

@@ -1094,7 +1094,7 @@ gen_expand_wildcards (
       free(t);
     }
 
-    if (did_expand_in_path && ga.ga_len > 0 && (flags & EW_PATH))
+    if (did_expand_in_path && !GA_EMPTY(&ga) && (flags & EW_PATH))
       uniquefy_paths(&ga, p);
     if (p != pat[i])
       free(p);

src/nvim/regexp.c

@@ -4697,7 +4697,7 @@ regmatch (
      * If there is something on the regstack execute the code for the state.
      * If the state is popped then loop and use the older state.
      */
-    while (regstack.ga_len > 0 && status != RA_FAIL) {
+    while (!GA_EMPTY(&regstack) && status != RA_FAIL) {
       rp = (regitem_T *)((char *)regstack.ga_data + regstack.ga_len) - 1;
       switch (rp->rs_state) {
       case RS_NOPEN:

src/nvim/screen.c

@@ -2380,7 +2380,7 @@ win_line (
 
   if (wp->w_p_spell
       && *wp->w_s->b_p_spl != NUL
-      && wp->w_s->b_langp.ga_len > 0
+      && !GA_EMPTY(&wp->w_s->b_langp)
       && *(char **)(wp->w_s->b_langp.ga_data) != NULL) {
     /* Prepare for spell checking. */
     has_spell = TRUE;

src/nvim/spell.c

@@ -2324,7 +2324,7 @@ static void slang_clear(slang_T *lp)
 
   for (round = 1; round <= 2; ++round) {
     gap = round == 1 ? &lp->sl_rep : &lp->sl_repsal;
-    while (gap->ga_len > 0) {
+    while (!GA_EMPTY(gap)) {
       ftp = &((fromto_T *)gap->ga_data)[--gap->ga_len];
       free(ftp->ft_from);
       free(ftp->ft_to);
@@ -2341,7 +2341,7 @@ static void slang_clear(slang_T *lp)
         free(((int **)gap->ga_data)[i]);
   } else
     // SAL items: free salitem_T items
-    while (gap->ga_len > 0) {
+    while (!GA_EMPTY(gap)) {
       smp = &((salitem_T *)gap->ga_data)[--gap->ga_len];
       free(smp->sm_lead);
       // Don't free sm_oneof and sm_rules, they point into sm_lead.
@@ -2915,7 +2915,7 @@ static int read_sal_section(FILE *fd, slang_T *slang)
     }
   }
 
-  if (gap->ga_len > 0) {
+  if (!GA_EMPTY(gap)) {
     // Add one extra entry to mark the end with an empty sm_lead.  Avoids
     // that we need to check the index every time.
     smp = &((salitem_T *)gap->ga_data)[gap->ga_len];
@@ -3865,14 +3865,14 @@ char_u *did_set_spelllang(win_T *wp)
     lp = LANGP_ENTRY(ga, i);
 
     // sound folding
-    if (lp->lp_slang->sl_sal.ga_len > 0)
+    if (!GA_EMPTY(&lp->lp_slang->sl_sal))
       // language does sound folding itself
       lp->lp_sallang = lp->lp_slang;
     else
       // find first similar language that does sound folding
       for (j = 0; j < ga.ga_len; ++j) {
         lp2 = LANGP_ENTRY(ga, j);
-        if (lp2->lp_slang->sl_sal.ga_len > 0
+        if (!GA_EMPTY(&lp2->lp_slang->sl_sal)
             && STRNCMP(lp->lp_slang->sl_name,
                 lp2->lp_slang->sl_name, 2) == 0) {
           lp->lp_sallang = lp2->lp_slang;
@@ -3881,14 +3881,14 @@ char_u *did_set_spelllang(win_T *wp)
       }
 
     // REP items
-    if (lp->lp_slang->sl_rep.ga_len > 0)
+    if (!GA_EMPTY(&lp->lp_slang->sl_rep))
       // language has REP items itself
       lp->lp_replang = lp->lp_slang;
     else
       // find first similar language that has REP items
       for (j = 0; j < ga.ga_len; ++j) {
         lp2 = LANGP_ENTRY(ga, j);
-        if (lp2->lp_slang->sl_rep.ga_len > 0
+        if (!GA_EMPTY(&lp2->lp_slang->sl_rep)
             && STRNCMP(lp->lp_slang->sl_name,
                 lp2->lp_slang->sl_name, 2) == 0) {
           lp->lp_replang = lp2->lp_slang;
@@ -5131,7 +5131,7 @@ static afffile_T *spell_read_aff(spellinfo_T *spin, char_u *fname)
           // Check that every character appears only once.
           for (p = items[1]; *p != NUL; ) {
             c = mb_ptr2char_adv(&p);
-            if ((spin->si_map.ga_len > 0
+            if ((!GA_EMPTY(&spin->si_map)
                  && vim_strchr(spin->si_map.ga_data, c)
                  != NULL)
                 || vim_strchr(p, c) != NULL)
@@ -5257,7 +5257,7 @@ static afffile_T *spell_read_aff(spellinfo_T *spin, char_u *fname)
     if (sofofrom == NULL || sofoto == NULL)
       smsg((char_u *)_("Missing SOFO%s line in %s"),
           sofofrom == NULL ? "FROM" : "TO", fname);
-    else if (spin->si_sal.ga_len > 0)
+    else if (!GA_EMPTY(&spin->si_sal))
       smsg((char_u *)_("Both SAL and SOFO lines in %s"), fname);
     else {
       aff_check_string(spin->si_sofofr, sofofrom, "SOFOFROM");
@@ -6909,7 +6909,7 @@ static int write_vim_spell(spellinfo_T *spin, char_u *fname)
   }
 
   // SN_PREFCOND: <prefcondcnt> <prefcond> ...
-  if (spin->si_prefcond.ga_len > 0) {
+  if (!GA_EMPTY(&spin->si_prefcond)) {
     putc(SN_PREFCOND, fd);                              // <sectionID>
     putc(SNF_REQUIRED, fd);                             // <sectionflags>
 
@@ -7037,7 +7037,7 @@ static int write_vim_spell(spellinfo_T *spin, char_u *fname)
 
   // SN_MAP: <mapstr>
   // This is for making suggestions, section is not required.
-  if (spin->si_map.ga_len > 0) {
+  if (!GA_EMPTY(&spin->si_map)) {
     putc(SN_MAP, fd);                                   // <sectionID>
     putc(0, fd);                                        // <sectionflags>
     l = spin->si_map.ga_len;
@@ -7052,7 +7052,7 @@ static int write_vim_spell(spellinfo_T *spin, char_u *fname)
   // with this .spl file.  That's because the word numbers must be exactly
   // right.
   if (!spin->si_nosugfile
-      && (spin->si_sal.ga_len > 0
+      && (!GA_EMPTY(&spin->si_sal)
           || (spin->si_sofofr != NULL && spin->si_sofoto != NULL))) {
     putc(SN_SUGFILE, fd);                               // <sectionID>
     putc(0, fd);                                        // <sectionflags>
@@ -8151,7 +8151,7 @@ static void init_spellfile(void)
   int aspath = FALSE;
   char_u      *lstart = curbuf->b_s.b_p_spl;
 
-  if (*curwin->w_s->b_p_spl != NUL && curwin->w_s->b_langp.ga_len > 0) {
+  if (*curwin->w_s->b_p_spl != NUL && !GA_EMPTY(&curwin->w_s->b_langp)) {
     buf = alloc(MAXPATHL);
 
     // Find the end of the language name.  Exclude the region.  If there
@@ -11011,7 +11011,7 @@ static void score_comp_sal(suginfo_T *su)
   // Use the sound-folding of the first language that supports it.
   for (lpi = 0; lpi < curwin->w_s->b_langp.ga_len; ++lpi) {
     lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);
-    if (lp->lp_slang->sl_sal.ga_len > 0) {
+    if (!GA_EMPTY(&lp->lp_slang->sl_sal)) {
       // soundfold the bad word
       spell_soundfold(lp->lp_slang, su->su_fbadword, TRUE, badsound);
 
@@ -11058,7 +11058,7 @@ static void score_combine(suginfo_T *su)
   // Add the alternate score to su_ga.
   for (lpi = 0; lpi < curwin->w_s->b_langp.ga_len; ++lpi) {
     lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);
-    if (lp->lp_slang->sl_sal.ga_len > 0) {
+    if (!GA_EMPTY(&lp->lp_slang->sl_sal)) {
       // soundfold the bad word
       slang = lp->lp_slang;
       spell_soundfold(slang, su->su_fbadword, TRUE, badsound);
@@ -11216,7 +11216,7 @@ static void suggest_try_soundalike_prep(void)
   for (lpi = 0; lpi < curwin->w_s->b_langp.ga_len; ++lpi) {
     lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);
     slang = lp->lp_slang;
-    if (slang->sl_sal.ga_len > 0 && slang->sl_sbyts != NULL)
+    if (!GA_EMPTY(&slang->sl_sal) && slang->sl_sbyts != NULL)
       // prepare the hashtable used by add_sound_suggest()
       hash_init(&slang->sl_sounddone);
   }
@@ -11236,7 +11236,7 @@ static void suggest_try_soundalike(suginfo_T *su)
   for (lpi = 0; lpi < curwin->w_s->b_langp.ga_len; ++lpi) {
     lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);
     slang = lp->lp_slang;
-    if (slang->sl_sal.ga_len > 0 && slang->sl_sbyts != NULL) {
+    if (!GA_EMPTY(&slang->sl_sal) && slang->sl_sbyts != NULL) {
       // soundfold the bad word
       spell_soundfold(slang, su->su_fbadword, TRUE, salword);
 
@@ -11262,7 +11262,7 @@ static void suggest_try_soundalike_finish(void)
   for (lpi = 0; lpi < curwin->w_s->b_langp.ga_len; ++lpi) {
     lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);
     slang = lp->lp_slang;
-    if (slang->sl_sal.ga_len > 0 && slang->sl_sbyts != NULL) {
+    if (!GA_EMPTY(&slang->sl_sal) && slang->sl_sbyts != NULL) {
       // Free the info about handled words.
       todo = (int)slang->sl_sounddone.ht_used;
       for (hi = slang->sl_sounddone.ht_array; todo > 0; ++hi)
@@ -11825,7 +11825,7 @@ static void rescore_one(suginfo_T *su, suggest_T *stp)
 
   // Only rescore suggestions that have no sal score yet and do have a
   // language.
-  if (slang != NULL && slang->sl_sal.ga_len > 0 && !stp->st_had_bonus) {
+  if (slang != NULL && !GA_EMPTY(&slang->sl_sal) && !stp->st_had_bonus) {
     if (slang == su->su_sallang)
       p = su->su_sal_badword;
     else {
@@ -11899,7 +11899,7 @@ char_u *eval_soundfold(char_u *word)
     // Use the sound-folding of the first language that supports it.
     for (lpi = 0; lpi < curwin->w_s->b_langp.ga_len; ++lpi) {
       lp = LANGP_ENTRY(curwin->w_s->b_langp, lpi);
-      if (lp->lp_slang->sl_sal.ga_len > 0) {
+      if (!GA_EMPTY(&lp->lp_slang->sl_sal)) {
         // soundfold the word
         spell_soundfold(lp->lp_slang, word, FALSE, sound);
         return vim_strsave(sound);

src/nvim/syntax.c

@@ -951,7 +951,7 @@ static void syn_start_line(void)
    * Need to update the end of a start/skip/end that continues from the
    * previous line and regions that have "keepend".
    */
-  if (current_state.ga_len > 0) {
+  if (!GA_EMPTY(&current_state)) {
     syn_update_ends(TRUE);
     check_state_ends();
   }
@@ -2187,7 +2187,7 @@ syn_current_attr (
      */
     if (!syncing && !keep_state) {
       check_state_ends();
-      if (current_state.ga_len > 0
+      if (!GA_EMPTY(&current_state)
           && syn_getcurline()[current_col] != NUL) {
         ++current_col;
         check_state_ends();
@@ -2207,7 +2207,7 @@ syn_current_attr (
       && !(current_next_flags & (HL_SKIPNL | HL_SKIPEMPTY)))
     current_next_list = NULL;
 
-  if (zero_width_next_ga.ga_len > 0)
+  if (!GA_EMPTY(&zero_width_next_ga))
     ga_clear(&zero_width_next_ga);
 
   /* No longer need external matches.  But keep next_match_extmatch. */