vim-patch:8.0.1104: the qf_jump() function is too long

Problem:    The qf_jump() function is too long.
Solution:   Split of parts to separate functions. (Yegappan Lakshmanan)

https://github.com/vim/vim/commit/ef6b8de42f439271edcf5cf22b2450f2cf302c2e

1 files changed, 174 insertions, 103 deletions

diff --git a/src/nvim/quickfix.c b/src/nvim/quickfix.c
index ee1cf2182f..46bc9b6870 100644
--- a/src/nvim/quickfix.c
+++ b/src/nvim/quickfix.c
@@ -1725,6 +1725,168 @@ static bool is_qf_entry_present(qf_info_T *qi, qfline_T *qf_ptr)
   return true;
 }
 
+/// Get the next valid entry in the current quickfix/location list. The search
+/// starts from the current entry. If next_file is true, then return the next
+/// valid entry in the next file in the list. Returns NULL on failure.
+static qfline_T *get_next_valid_entry(qf_info_T *qi, qfline_T *qf_ptr,
+                                      int *qf_index, int dir)
+{
+  int idx = *qf_index;
+  int old_qf_fnum = qf_ptr->qf_fnum;
+
+  do {
+    if (idx == qi->qf_lists[qi->qf_curlist].qf_count
+        || qf_ptr->qf_next == NULL) {
+      return NULL;
+    }
+    idx++;
+    qf_ptr = qf_ptr->qf_next;
+  } while ((!qi->qf_lists[qi->qf_curlist].qf_nonevalid && !qf_ptr->qf_valid)
+           || (dir == FORWARD_FILE && qf_ptr->qf_fnum == old_qf_fnum));
+
+  *qf_index = idx;
+  return qf_ptr;
+}
+
+/// Get the previous valid entry in the current quickfix/location list. The
+/// search starts from the current entry. If prev_file is TRUE, then return the
+/// previous valid entry in the previous file in the list. Returns NULL on
+/// failure.
+static qfline_T *get_prev_valid_entry(qf_info_T *qi, qfline_T *qf_ptr,
+                                      int *qf_index, int dir)
+{
+  int idx = *qf_index;
+  int old_qf_fnum = qf_ptr->qf_fnum;
+
+  do {
+    if (idx == 1 || qf_ptr->qf_prev == NULL) {
+      return NULL;
+    }
+    idx--;
+    qf_ptr = qf_ptr->qf_prev;
+  } while ((!qi->qf_lists[qi->qf_curlist].qf_nonevalid && !qf_ptr->qf_valid)
+           || (dir == BACKWARD_FILE && qf_ptr->qf_fnum == old_qf_fnum));
+
+  *qf_index = idx;
+  return qf_ptr;
+}
+
+/// Get the n'th (errornr) previous/next valid entry from the current entry in
+/// the quickfix list.
+///   dir == FORWARD or FORWARD_FILE: next valid entry
+///   dir == BACKWARD or BACKWARD_FILE: previous valid entry
+static qfline_T *get_nth_valid_entry(qf_info_T *qi, int errornr,
+                                     qfline_T *qf_ptr, int *qf_index, int dir)
+{
+  qfline_T *prev_qf_ptr;
+  int prev_index;
+  static char_u *e_no_more_items = (char_u *)N_("E553: No more items");
+  char_u *err = e_no_more_items;
+
+  while (errornr--) {
+    prev_qf_ptr = qf_ptr;
+    prev_index = *qf_index;
+
+    if (dir == FORWARD || dir == FORWARD_FILE) {
+      qf_ptr = get_next_valid_entry(qi, qf_ptr, qf_index, dir);
+    } else {
+      qf_ptr = get_prev_valid_entry(qi, qf_ptr, qf_index, dir);
+    }
+
+    if (qf_ptr == NULL) {
+      qf_ptr = prev_qf_ptr;
+      *qf_index = prev_index;
+      if (err != NULL) {
+        EMSG(_(err));
+        return NULL;
+      }
+      break;
+    }
+
+    err = NULL;
+  }
+
+  return qf_ptr;
+}
+
+/// Get n'th quickfix entry
+static qfline_T *get_nth_entry(qf_info_T *qi, int errornr, qfline_T *qf_ptr,
+                               int *qf_index)
+{
+  int qf_idx = *qf_index;
+
+  while (errornr < qf_idx && qf_idx > 1 && qf_ptr->qf_prev != NULL) {
+    qf_idx--;
+    qf_ptr = qf_ptr->qf_prev;
+  }
+
+  while (errornr > qf_idx
+         && qf_idx < qi->qf_lists[qi->qf_curlist].qf_count
+         && qf_ptr->qf_next != NULL) {
+    qf_idx++;
+    qf_ptr = qf_ptr->qf_next;
+  }
+
+  *qf_index = qf_idx;
+  return qf_ptr;
+}
+
+/// Find a help window or open one.
+static int jump_to_help_window(qf_info_T *qi, int *opened_window)
+{
+  win_T *wp = NULL;
+
+  if (cmdmod.tab != 0) {
+    wp = NULL;
+  } else {
+    FOR_ALL_WINDOWS_IN_TAB(wp2, curtab) {
+      if (bt_help(wp2->w_buffer)) {
+        wp = wp2;
+        break;
+      }
+    }
+  }
+
+  if (wp != NULL && wp->w_buffer->b_nwindows > 0) {
+    win_enter(wp, true);
+  } else {
+    // Split off help window; put it at far top if no position
+    // specified, the current window is vertically split and narrow.
+    int flags = WSP_HELP;
+    if (cmdmod.split == 0
+        && curwin->w_width != Columns
+        && curwin->w_width < 80) {
+      flags |= WSP_TOP;
+    }
+
+    if (qi != &ql_info) {
+      flags |= WSP_NEWLOC;  // don't copy the location list
+    }
+
+    if (win_split(0, flags) == FAIL) {
+      return FAIL;
+    }
+
+    *opened_window = true;
+
+    if (curwin->w_height < p_hh) {
+      win_setheight((int)p_hh);
+    }
+
+    if (qi != &ql_info) {  // not a quickfix list
+      // The new window should use the supplied location list
+      curwin->w_llist = qi;
+      qi->qf_refcount++;
+    }
+  }
+
+  if (!p_im) {
+    restart_edit = 0;  // don't want insert mode in help file
+  }
+
+  return OK;
+}
+
 /*
  * jump to a quickfix line
  * if dir == FORWARD go "errornr" valid entries forward
@@ -1740,11 +1902,7 @@ void qf_jump(qf_info_T *qi, int dir, int errornr, int forceit)
   qfline_T            *qf_ptr;
   qfline_T            *old_qf_ptr;
   int qf_index;
-  int old_qf_fnum;
   int old_qf_index;
-  int prev_index;
-  static char_u       *e_no_more_items = (char_u *)N_("E553: No more items");
-  char_u              *err = e_no_more_items;
   linenr_T i;
   buf_T               *old_curbuf;
   linenr_T old_lnum;
@@ -1777,64 +1935,16 @@ void qf_jump(qf_info_T *qi, int dir, int errornr, int forceit)
   old_qf_ptr = qf_ptr;
   qf_index = qi->qf_lists[qi->qf_curlist].qf_index;
   old_qf_index = qf_index;
-  if (dir == FORWARD || dir == FORWARD_FILE) {      /* next valid entry */
-    while (errornr--) {
-      old_qf_ptr = qf_ptr;
-      prev_index = qf_index;
-      old_qf_fnum = qf_ptr->qf_fnum;
-      do {
-        if (qf_index == qi->qf_lists[qi->qf_curlist].qf_count
-            || qf_ptr->qf_next == NULL) {
-          qf_ptr = old_qf_ptr;
-          qf_index = prev_index;
-          if (err != NULL) {
-            EMSG(_(err));
-            goto theend;
-          }
-          errornr = 0;
-          break;
-        }
-        ++qf_index;
-        qf_ptr = qf_ptr->qf_next;
-      } while ((!qi->qf_lists[qi->qf_curlist].qf_nonevalid
-                && !qf_ptr->qf_valid)
-               || (dir == FORWARD_FILE && qf_ptr->qf_fnum == old_qf_fnum));
-      err = NULL;
-    }
-  } else if (dir == BACKWARD || dir == BACKWARD_FILE) { /* prev. valid entry */
-    while (errornr--) {
-      old_qf_ptr = qf_ptr;
-      prev_index = qf_index;
-      old_qf_fnum = qf_ptr->qf_fnum;
-      do {
-        if (qf_index == 1 || qf_ptr->qf_prev == NULL) {
-          qf_ptr = old_qf_ptr;
-          qf_index = prev_index;
-          if (err != NULL) {
-            EMSG(_(err));
-            goto theend;
-          }
-          errornr = 0;
-          break;
-        }
-        --qf_index;
-        qf_ptr = qf_ptr->qf_prev;
-      } while ((!qi->qf_lists[qi->qf_curlist].qf_nonevalid
-                && !qf_ptr->qf_valid)
-               || (dir == BACKWARD_FILE && qf_ptr->qf_fnum == old_qf_fnum));
-      err = NULL;
-    }
-  } else if (errornr != 0) {  /* go to specified number */
-    while (errornr < qf_index && qf_index > 1 && qf_ptr->qf_prev != NULL) {
-      --qf_index;
-      qf_ptr = qf_ptr->qf_prev;
-    }
-    while (errornr > qf_index && qf_index <
-           qi->qf_lists[qi->qf_curlist].qf_count
-           && qf_ptr->qf_next != NULL) {
-      ++qf_index;
-      qf_ptr = qf_ptr->qf_next;
+  if (dir == FORWARD || dir == FORWARD_FILE || dir == BACKWARD
+      || dir == BACKWARD_FILE) {  // next/prev valid entry
+    qf_ptr = get_nth_valid_entry(qi, errornr, qf_ptr, &qf_index, dir);
+    if (qf_ptr == NULL) {
+      qf_ptr = old_qf_ptr;
+      qf_index = old_qf_index;
+      goto theend;  // The horror... the horror...
     }
+  } else if (errornr != 0) {  // go to specified number
+    qf_ptr = get_nth_entry(qi, errornr, qf_ptr, &qf_index);
   }
 
   qi->qf_lists[qi->qf_curlist].qf_index = qf_index;
@@ -1843,50 +1953,11 @@ void qf_jump(qf_info_T *qi, int dir, int errornr, int forceit)
      * window */
     print_message = FALSE;
 
-  /*
-   * For ":helpgrep" find a help window or open one.
-   */
+  // For ":helpgrep" find a help window or open one.
   if (qf_ptr->qf_type == 1 && (!bt_help(curwin->w_buffer) || cmdmod.tab != 0)) {
-    win_T *wp = NULL;
-
-    if (cmdmod.tab == 0) {
-      FOR_ALL_WINDOWS_IN_TAB(wp2, curtab) {
-        if (bt_help(wp2->w_buffer)) {
-          wp = wp2;
-          break;
-        }
-      }
-    }
-    if (wp != NULL && wp->w_buffer->b_nwindows > 0)
-      win_enter(wp, true);
-    else {
-      /*
-       * Split off help window; put it at far top if no position
-       * specified, the current window is vertically split and narrow.
-       */
-      flags = WSP_HELP;
-      if (cmdmod.split == 0 && curwin->w_width != Columns
-          && curwin->w_width < 80)
-        flags |= WSP_TOP;
-      if (qi != &ql_info)
-        flags |= WSP_NEWLOC;          /* don't copy the location list */
-
-      if (win_split(0, flags) == FAIL)
-        goto theend;
-      opened_window = TRUE;             /* close it when fail */
-
-      if (curwin->w_height < p_hh)
-        win_setheight((int)p_hh);
-
-      if (qi != &ql_info) {         /* not a quickfix list */
-        /* The new window should use the supplied location list */
-        curwin->w_llist = qi;
-        qi->qf_refcount++;
-      }
+    if (jump_to_help_window(qi, &opened_window) == FAIL) {
+      goto theend;
     }
-
-    if (!p_im)
-      restart_edit = 0;             /* don't want insert mode in help file */
   }
 
   /*