ex_getln: Make get_histtype return HIST_DEFAULT if needed

3 files changed, 75 insertions, 48 deletions

diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index a193c82f9d..e6d2f69281 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -11144,7 +11144,7 @@ static void f_hasmapto(typval_T *argvars, typval_T *rettv)
  */
 static void f_histadd(typval_T *argvars, typval_T *rettv)
 {
-  int histype;
+  HistoryType histype;
   char_u      *str;
   char_u buf[NUMBUFLEN];
 
@@ -11152,8 +11152,8 @@ static void f_histadd(typval_T *argvars, typval_T *rettv)
   if (check_restricted() || check_secure())
     return;
   str = get_tv_string_chk(&argvars[0]);         /* NULL on type error */
-  histype = str != NULL ? get_histtype(str, STRLEN(str)) : -1;
-  if (histype >= 0) {
+  histype = str != NULL ? get_histtype(str, STRLEN(str), false) : HIST_INVALID;
+  if (histype != HIST_INVALID) {
     str = get_tv_string_buf(&argvars[1], buf);
     if (*str != NUL) {
       init_history();
@@ -11178,14 +11178,14 @@ static void f_histdel(typval_T *argvars, typval_T *rettv)
     n = 0;
   else if (argvars[1].v_type == VAR_UNKNOWN)
     /* only one argument: clear entire history */
-    n = clr_history(get_histtype(str, STRLEN(str)));
+    n = clr_history(get_histtype(str, STRLEN(str), false));
   else if (argvars[1].v_type == VAR_NUMBER)
     /* index given: remove that entry */
-    n = del_history_idx(get_histtype(str, STRLEN(str)),
+    n = del_history_idx(get_histtype(str, STRLEN(str), false),
         (int)get_tv_number(&argvars[1]));
   else
     /* string given: remove all matching entries */
-    n = del_history_entry(get_histtype(str, STRLEN(str)),
+    n = del_history_entry(get_histtype(str, STRLEN(str), false),
         get_tv_string_buf(&argvars[1], buf));
   rettv->vval.v_number = n;
 }
@@ -11195,20 +11195,21 @@ static void f_histdel(typval_T *argvars, typval_T *rettv)
  */
 static void f_histget(typval_T *argvars, typval_T *rettv)
 {
-  int type;
+  HistoryType type;
   int idx;
   char_u      *str;
 
   str = get_tv_string_chk(&argvars[0]);         /* NULL on type error */
-  if (str == NULL)
+  if (str == NULL) {
     rettv->vval.v_string = NULL;
-  else {
-    type = get_histtype(str, STRLEN(str));
-    if (argvars[1].v_type == VAR_UNKNOWN)
+  } else {
+    type = get_histtype(str, STRLEN(str), false);
+    if (argvars[1].v_type == VAR_UNKNOWN) {
       idx = get_history_idx(type);
-    else
+    } else {
       idx = (int)get_tv_number_chk(&argvars[1], NULL);
-    /* -1 on type error */
+    }
+    // -1 on type error
     rettv->vval.v_string = vim_strsave(get_history_entry(type, idx));
   }
   rettv->v_type = VAR_STRING;
@@ -11223,8 +11224,9 @@ static void f_histnr(typval_T *argvars, typval_T *rettv)
 
   char_u      *history = get_tv_string_chk(&argvars[0]);
 
-  i = history == NULL ? HIST_CMD - 1 : get_histtype(history, STRLEN(history));
-  if (i >= HIST_CMD && i < HIST_COUNT)
+  i = history == NULL ? HIST_CMD - 1 : get_histtype(history, STRLEN(history),
+                                                    false);
+  if (i != HIST_INVALID)
     i = get_history_idx(i);
   else
     i = -1;
diff --git a/src/nvim/ex_getln.c b/src/nvim/ex_getln.c
index 0c2848da98..a9e9ee76d5 100644
--- a/src/nvim/ex_getln.c
+++ b/src/nvim/ex_getln.c
@@ -4272,20 +4272,33 @@ void globpath(char_u *path, char_u *file, garray_T *ga, int expand_options)
 *  Command line history stuff	 *
 *********************************/
 
-/*
- * Translate a history character to the associated type number.
- */
-static int hist_char2type(int c)
+/// Translate a history character to the associated type number
+static HistoryType hist_char2type(const int c)
+  FUNC_ATTR_CONST FUNC_ATTR_WARN_UNUSED_RESULT
 {
-  if (c == ':')
-    return HIST_CMD;
-  if (c == '=')
-    return HIST_EXPR;
-  if (c == '@')
-    return HIST_INPUT;
-  if (c == '>')
-    return HIST_DEBUG;
-  return HIST_SEARCH;       /* must be '?' or '/' */
+  switch (c) {
+    case ':': {
+      return HIST_CMD;
+    }
+    case '=': {
+      return HIST_EXPR;
+    }
+    case '@': {
+      return HIST_INPUT;
+    }
+    case '>': {
+      return HIST_DEBUG;
+    }
+    case '/':
+    case '?': {
+      return HIST_SEARCH;
+    }
+    default: {
+      assert(false);
+    }
+  }
+  // Silence -Wreturn-type
+  return 0;
 }
 
 /*
@@ -4454,28 +4467,38 @@ in_history (
   return false;
 }
 
-/*
- * Convert history name (from table above) to its HIST_ equivalent.
- * When "name" is empty, return "cmd" history.
- * Returns -1 for unknown history name.
- */
-int get_histtype(char_u *name, size_t len)
+/// Convert history name to its HIST_ equivalent
+///
+/// Names are taken from the table above. When `name` is empty returns currently
+/// active history or HIST_DEFAULT, depending on `return_default` argument.
+///
+/// @param[in]  name            Converted name.
+/// @param[in]  len             Name length.
+/// @param[in]  return_default  Determines whether HIST_DEFAULT should be
+///                             returned or value based on `ccline.cmdfirstc`.
+///
+/// @return Any value from HistoryType enum, including HIST_INVALID. May not
+///         return HIST_DEFAULT unless return_default is true.
+HistoryType get_histtype(const char_u *const name, const size_t len,
+                         const bool return_default)
+  FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
 {
-  int i;
-
-  /* No argument: use current history. */
-  if (len == 0)
-    return hist_char2type(ccline.cmdfirstc);
+  // No argument: use current history.
+  if (len == 0) {
+    return return_default ? HIST_DEFAULT :hist_char2type(ccline.cmdfirstc);
+  }
 
-  for (i = 0; history_names[i] != NULL; ++i)
-    if (STRNICMP(name, history_names[i], len) == 0)
+  for (HistoryType i = 0; history_names[i] != NULL; i++) {
+    if (STRNICMP(name, history_names[i], len) == 0) {
       return i;
+    }
+  }
 
   if (vim_strchr((char_u *)":=@>?/", name[0]) != NULL && len == 1) {
     return hist_char2type(name[0]);
   }
 
-  return -1;
+  return HIST_INVALID;
 }
 
 static int last_maptick = -1;           /* last seen maptick */
@@ -4847,7 +4870,7 @@ void ex_history(exarg_T *eap)
     while (ASCII_ISALPHA(*end)
            || vim_strchr((char_u *)":=@>/?", *end) != NULL)
       end++;
-    histype1 = get_histtype(arg, end - arg);
+    histype1 = get_histtype(arg, end - arg, false);
     if (histype1 == HIST_INVALID) {
       if (STRNICMP(arg, "all", end - arg) == 0) {
         histype1 = 0;
diff --git a/src/nvim/ex_getln.h b/src/nvim/ex_getln.h
index 21da8b9d42..24eebdc303 100644
--- a/src/nvim/ex_getln.h
+++ b/src/nvim/ex_getln.h
@@ -27,11 +27,13 @@
 
 /// Present history tables
 typedef enum {
-  HIST_CMD,     ///< Colon commands.
-  HIST_SEARCH,  ///< Search commands.
-  HIST_EXPR,    ///< Expressions (e.g. from entering = register).
-  HIST_INPUT,   ///< input() lines.
-  HIST_DEBUG,   ///< Debug commands.
+  HIST_DEFAULT = -2,  ///< Default (current) history.
+  HIST_INVALID = -1,  ///< Unknown history.
+  HIST_CMD = 0,       ///< Colon commands.
+  HIST_SEARCH,        ///< Search commands.
+  HIST_EXPR,          ///< Expressions (e.g. from entering = register).
+  HIST_INPUT,         ///< input() lines.
+  HIST_DEBUG,         ///< Debug commands.
 } HistoryType;
 
 /// Number of history tables