vim-patch:8.1.0010: efm_to_regpat() is too long

Problem:    efm_to_regpat() is too long.
Solution:   Split off three functions. (Yegappan Lakshmanan, closes vim/vim#2924)
6bff719f7e

src/nvim/quickfix.c

@@ -264,42 +264,35 @@ static struct fmtpattern
   { 'o', ".\\+" }
 };
 
-// Converts a 'errorformat' string to regular expression pattern
+// Convert an errorformat pattern to a regular expression pattern.
-static int efm_to_regpat(char_u *efm, int len, efm_T *fmt_ptr,
+// See fmt_pat definition above for the list of supported patterns.
-                         char_u *regpat, char_u *errmsg)
+static char_u *fmtpat_to_regpat(
+    const char_u *efmp,
+    efm_T *fmt_ptr,
+    int idx,
+    int round,
+    char_u *ptr,
+    char_u *errmsg,
+    size_t errmsglen)
+  FUNC_ATTR_NONNULL_ALL
 {
-  // Build regexp pattern from current 'errorformat' option
-  char_u *ptr = regpat;
-  *ptr++ = '^';
-  int round = 0;
-  for (char_u *efmp = efm; efmp < efm + len; efmp++) {
-    if (*efmp == '%') {
-      efmp++;
-      int idx;
-      for (idx = 0; idx < FMT_PATTERNS; idx++) {
-        if (fmt_pat[idx].convchar == *efmp) {
-          break;
-        }
-      }
-      if (idx < FMT_PATTERNS) {
   if (fmt_ptr->addr[idx]) {
-          snprintf((char *)errmsg, CMDBUFFSIZE + 1,
+    // Each errorformat pattern can occur only once
+    snprintf((char *)errmsg, errmsglen,
              _("E372: Too many %%%c in format string"), *efmp);
     EMSG(errmsg);
-          return -1;
+    return NULL;
   }
-        if ((idx
+  if ((idx && idx < 6
-             && idx < 6
        && vim_strchr((char_u *)"DXOPQ", fmt_ptr->prefix) != NULL)
       || (idx == 6
           && vim_strchr((char_u *)"OPQ", fmt_ptr->prefix) == NULL)) {
-          snprintf((char *)errmsg, CMDBUFFSIZE + 1,
+    snprintf((char *)errmsg, errmsglen,
              _("E373: Unexpected %%%c in format string"), *efmp);
     EMSG(errmsg);
-          return -1;
+    return NULL;
   }
-        round++;
+  fmt_ptr->addr[idx] = (char_u)++round;
-        fmt_ptr->addr[idx] = (char_u)round;
   *ptr++ = '\\';
   *ptr++ = '(';
 #ifdef BACKSLASH_IN_FILENAME
@@ -334,37 +327,107 @@ static int efm_to_regpat(char_u *efm, int len, efm_T *fmt_ptr,
   }
   *ptr++ = '\\';
   *ptr++ = ')';
-      } else if (*efmp == '*') {
+
+  return ptr;
+}
+
+// Convert a scanf like format in 'errorformat' to a regular expression.
+static char_u *scanf_fmt_to_regpat(
+    const char_u *efm,
+    int len,
+    const char_u **pefmp,
+    char_u *ptr,
+    char_u *errmsg,
+    size_t errmsglen)
+  FUNC_ATTR_NONNULL_ALL
+{
+  const char_u *efmp = *pefmp;
+
   if (*++efmp == '[' || *efmp == '\\') {
     if ((*ptr++ = *efmp) == '[') {  // %*[^a-z0-9] etc.
       if (efmp[1] == '^') {
         *ptr++ = *++efmp;
       }
       if (efmp < efm + len) {
-              efmp++;
+        *ptr++ = *++efmp;  // could be ']'
-              *ptr++ = *efmp;    // could be ']'
+        while (efmp < efm + len && (*ptr++ = *++efmp) != ']') {
-              while (efmp < efm + len) {
-                efmp++;
-                if ((*ptr++ = *efmp) == ']') {
-                  break;
-                }
         }
         if (efmp == efm + len) {
           EMSG(_("E374: Missing ] in format string"));
-                return -1;
+          return NULL;
         }
       }
     } else if (efmp < efm + len) {  // %*\D, %*\s etc.
-            efmp++;
+      *ptr++ = *++efmp;
-            *ptr++ = *efmp;
     }
     *ptr++ = '\\';
     *ptr++ = '+';
   } else {
     // TODO(vim): scanf()-like: %*ud, %*3c, %*f, ... ?
-          snprintf((char *)errmsg, CMDBUFFSIZE + 1,
+    snprintf((char *)errmsg, errmsglen,
              _("E375: Unsupported %%%c in format string"), *efmp);
     EMSG(errmsg);
+    return NULL;
+  }
+
+  *pefmp = efmp;
+
+  return ptr;
+}
+
+// Analyze/parse an errorformat prefix.
+static int efm_analyze_prefix(const char_u **pefmp, efm_T *fmt_ptr,
+                              char_u *errmsg, size_t errmsglen)
+  FUNC_ATTR_NONNULL_ALL
+{
+  const char_u *efmp = *pefmp;
+
+  if (vim_strchr((char_u *)"+-", *efmp) != NULL) {
+    fmt_ptr->flags = *efmp++;
+  }
+  if (vim_strchr((char_u *)"DXAEWICZGOPQ", *efmp) != NULL) {
+    fmt_ptr->prefix = *efmp;
+  } else {
+    snprintf((char *)errmsg, errmsglen,
+             _("E376: Invalid %%%c in format string prefix"), *efmp);
+    EMSG(errmsg);
+    return FAIL;
+  }
+
+  *pefmp = efmp;
+
+  return OK;
+}
+
+
+// Converts a 'errorformat' string to regular expression pattern
+static int efm_to_regpat(const char_u *efm, int len, efm_T *fmt_ptr,
+                         char_u *regpat, char_u *errmsg, size_t errmsglen)
+  FUNC_ATTR_NONNULL_ALL
+{
+  // Build regexp pattern from current 'errorformat' option
+  char_u *ptr = regpat;
+  *ptr++ = '^';
+  int round = 0;
+  for (const char_u *efmp = efm; efmp < efm + len; efmp++) {
+    if (*efmp == '%') {
+      efmp++;
+      int idx;
+      for (idx = 0; idx < FMT_PATTERNS; idx++) {
+        if (fmt_pat[idx].convchar == *efmp) {
+          break;
+        }
+      }
+      if (idx < FMT_PATTERNS) {
+        ptr = fmtpat_to_regpat(efmp, fmt_ptr, idx, round, ptr,
+                               errmsg, errmsglen);
+        if (ptr == NULL) {
+          return -1;
+        }
+        round++;
+      } else if (*efmp == '*') {
+        ptr = scanf_fmt_to_regpat(efm, len, &efmp, ptr, errmsg, errmsglen);
+        if (ptr == NULL) {
           return -1;
         }
       } else if (vim_strchr((char_u *)"%\\.^$~[", *efmp) != NULL) {
@@ -374,15 +437,7 @@ static int efm_to_regpat(char_u *efm, int len, efm_T *fmt_ptr,
       } else if (*efmp == '>') {
         fmt_ptr->conthere = true;
       } else if (efmp == efm + 1) {             // analyse prefix
-        if (vim_strchr((char_u *)"+-", *efmp) != NULL) {
+        if (efm_analyze_prefix(&efmp, fmt_ptr, errmsg, errmsglen) == FAIL) {
-          fmt_ptr->flags = *efmp++;
-        }
-        if (vim_strchr((char_u *)"DXAEWICZGOPQ", *efmp) != NULL) {
-          fmt_ptr->prefix = *efmp;
-        } else {
-          snprintf((char *)errmsg, CMDBUFFSIZE + 1,
-                   _("E376: Invalid %%%c in format string prefix"), *efmp);
-          EMSG(errmsg);
           return -1;
         }
       } else {
@@ -461,7 +516,7 @@ static efm_T * parse_efm_option(char_u *efm)
       }
     }
 
-    if (efm_to_regpat(efm, len, fmt_ptr, fmtstr, errmsg) == -1) {
+    if (efm_to_regpat(efm, len, fmt_ptr, fmtstr, errmsg, errmsglen) == -1) {
       goto parse_efm_error;
     }
     if ((fmt_ptr->prog = vim_regcomp(fmtstr, RE_MAGIC + RE_STRING)) == NULL) {