patch 8.0.1812: the qf_jump_to_usable_window() function is too long

Problem:    The qf_jump_to_usable_window() function is too long.
Solution:   Split it in parts. (Yegappan Lakshmanan, closes #2891)

src/quickfix.c

@@ -2027,7 +2027,7 @@ qf_clean_dir_stack(struct dir_stack_T **stackptr)
  * Cleans up intermediate directory entries.
  *
  * TODO: How to solve the following problem?
- * If we have the this directory tree:
+ * If we have this directory tree:
  *     ./
  *     ./aa
  *     ./aa/bb
@@ -2079,7 +2079,7 @@ qf_guess_filepath(qf_info_T *qi, int qf_idx, char_u *filename)
 	vim_free(ds_tmp);
     }
 
-    return ds_ptr==NULL? NULL: ds_ptr->dirname;
+    return ds_ptr == NULL ? NULL : ds_ptr->dirname;
 }
 
 /*
@@ -2108,7 +2108,7 @@ qflist_valid (win_T *wp, int_u qf_id)
 /*
  * When loading a file from the quickfix, the auto commands may modify it.
  * This may invalidate the current quickfix entry.  This function checks
- * whether a entry is still present in the quickfix.
+ * whether an entry is still present in the quickfix list.
  * Similar to location list.
  */
     static int
@@ -2272,6 +2272,21 @@ get_nth_entry(
     return qf_ptr;
 }
 
+/*
+ * Find a window displaying a Vim help file.
+ */
+    static win_T *
+qf_find_help_win(void)
+{
+    win_T *wp;
+
+    FOR_ALL_WINDOWS(wp)
+	if (bt_help(wp->w_buffer))
+	    return wp;
+
+    return NULL;
+}
+
 /*
  * Find a help window or open one.
  */
@@ -2284,9 +2299,7 @@ jump_to_help_window(qf_info_T *qi, int *opened_window)
     if (cmdmod.tab != 0)
 	wp = NULL;
     else
-	FOR_ALL_WINDOWS(wp)
+	wp = qf_find_help_win();
-	    if (bt_help(wp->w_buffer))
-		break;
     if (wp != NULL && wp->w_buffer->b_nwindows > 0)
 	win_enter(wp, TRUE);
     else
@@ -2325,79 +2338,70 @@ jump_to_help_window(qf_info_T *qi, int *opened_window)
 }
 
 /*
- * Find a suitable window for opening a file (qf_fnum) and jump to it.
+ * Find a non-quickfix window using the given location list.
- * If the file is already opened in a window, jump to it.
+ * Returns NULL if a matching window is not found.
+ */
+    static win_T *
+qf_find_win_with_loclist(qf_info_T *ll)
+{
+    win_T	*wp;
+
+    FOR_ALL_WINDOWS(wp)
+	if (wp->w_llist == ll && !bt_quickfix(wp->w_buffer))
+	    return wp;
+
+    return NULL;
+}
+
+/*
+ * Find a window containing a normal buffer
+ */
+    static win_T *
+qf_find_win_with_normal_buf(void)
+{
+    win_T	*wp;
+
+    FOR_ALL_WINDOWS(wp)
+	if (wp->w_buffer->b_p_bt[0] == NUL)
+	    return wp;
+
+    return NULL;
+}
+
+/*
+ * Go to a window in any tabpage containing the specified file.  Returns TRUE
+ * if successfully jumped to the window. Otherwise returns FALSE.
  */
     static int
-qf_jump_to_usable_window(int qf_fnum, int *opened_window)
+qf_goto_tabwin_with_file(int fnum)
 {
-    win_T	*usable_win_ptr = NULL;
-    int		usable_win;
-    qf_info_T	*ll_ref;
-    int		flags;
-    win_T	*win;
-    win_T	*altwin;
-
-    usable_win = 0;
-
-    ll_ref = curwin->w_llist_ref;
-    if (ll_ref != NULL)
-    {
-	/* Find a window using the same location list that is not a
-	 * quickfix window. */
-	FOR_ALL_WINDOWS(usable_win_ptr)
-	    if (usable_win_ptr->w_llist == ll_ref
-		    && !bt_quickfix(usable_win_ptr->w_buffer))
-	    {
-		usable_win = 1;
-		break;
-	    }
-    }
-
-    if (!usable_win)
-    {
-	/* Locate a window showing a normal buffer */
-	FOR_ALL_WINDOWS(win)
-	    if (win->w_buffer->b_p_bt[0] == NUL)
-	    {
-		usable_win = 1;
-		break;
-	    }
-    }
-
-    /*
-     * If no usable window is found and 'switchbuf' contains "usetab"
-     * then search in other tabs.
-     */
-    if (!usable_win && (swb_flags & SWB_USETAB))
-    {
     tabpage_T	*tp;
     win_T	*wp;
 
     FOR_ALL_TAB_WINDOWS(tp, wp)
-	{
+	if (wp->w_buffer->b_fnum == fnum)
-	    if (wp->w_buffer->b_fnum == qf_fnum)
 	{
 	    goto_tabpage_win(tp, wp);
-		usable_win = 1;
+	    return TRUE;
-		goto win_found;
 	}
-	}
-    }
-win_found:
 
-    /*
+    return FALSE;
-     * If there is only one window and it is the quickfix window, create a
+}
-     * new one above the quickfix window.
+
+/*
+ * Create a new window to show a file above the quickfix window. Called when
+ * only the quickfix window is present.
  */
-    if ((ONE_WINDOW && bt_quickfix(curbuf)) || !usable_win)
+    static int
-    {
+qf_open_new_file_win(qf_info_T *ll_ref)
+{
+    int		flags;
+
     flags = WSP_ABOVE;
     if (ll_ref != NULL)
 	flags |= WSP_NEWLOC;
     if (win_split(0, flags) == FAIL)
 	return FAIL;		/* not enough room for window */
-	*opened_window = TRUE;	/* close it when fail */
     p_swb = empty_option;	/* don't split again */
     swb_flags = 0;
     RESET_BINDING(curwin);
@@ -2408,13 +2412,20 @@ win_found:
 	curwin->w_llist = ll_ref;
 	ll_ref->qf_refcount++;
     }
-    }
+    return OK;
-    else
+}
-    {
+
-	if (curwin->w_llist_ref != NULL)
+/*
-	{
+ * Go to a window that shows the right buffer. If the window is not found, go
-	    /* In a location window */
+ * to the window just above the location list window. This is used for opening
-	    win = usable_win_ptr;
+ * a file from a location window and not from a quickfix window. If some usable
+ * window is previously found, then it is supplied in 'use_win'.
+ */
+    static void
+qf_goto_win_with_ll_file(win_T *use_win, int qf_fnum, qf_info_T *ll_ref)
+{
+    win_T	*win = use_win;
+
     if (win == NULL)
     {
 	/* Find the window showing the selected file */
@@ -2445,14 +2456,19 @@ win_found:
 	win->w_llist = ll_ref;
 	ll_ref->qf_refcount++;
     }
-	}
+}
-	else
-	{
 
-	    /*
+/*
-	     * Try to find a window that shows the right buffer.
+ * Go to a window that shows the specified file. If a window is not found, go
-	     * Default to the window just above the quickfix buffer.
+ * to the window just above the quickfix window. This is used for opening a
+ * file from a quickfix window and not from a location window.
  */
+    static void
+qf_goto_win_with_qfl_file(int qf_fnum)
+{
+    win_T	*win;
+    win_T	*altwin;
+
     win = curwin;
     altwin = NULL;
     for (;;)
@@ -2484,7 +2500,64 @@ win_found:
     }
 
     win_goto(win);
+}
+
+/*
+ * Find a suitable window for opening a file (qf_fnum) from the
+ * quickfix/location list and jump to it.  If the file is already opened in a
+ * window, jump to it. Otherwise open a new window to display the file. This is
+ * called from either a quickfix or a location list window.
+ */
+    static int
+qf_jump_to_usable_window(int qf_fnum, int *opened_window)
+{
+    win_T	*usable_win_ptr = NULL;
+    int		usable_win;
+    qf_info_T	*ll_ref;
+    win_T	*win;
+
+    usable_win = 0;
+
+    ll_ref = curwin->w_llist_ref;
+    if (ll_ref != NULL)
+    {
+	/* Find a non-quickfix window with this location list */
+	usable_win_ptr = qf_find_win_with_loclist(ll_ref);
+	if (usable_win_ptr != NULL)
+	    usable_win = 1;
     }
+
+    if (!usable_win)
+    {
+	/* Locate a window showing a normal buffer */
+	win = qf_find_win_with_normal_buf();
+	if (win != NULL)
+	    usable_win = 1;
+    }
+
+    /*
+     * If no usable window is found and 'switchbuf' contains "usetab"
+     * then search in other tabs.
+     */
+    if (!usable_win && (swb_flags & SWB_USETAB))
+	usable_win = qf_goto_tabwin_with_file(qf_fnum);
+
+    /*
+     * If there is only one window and it is the quickfix window, create a
+     * new one above the quickfix window.
+     */
+    if ((ONE_WINDOW && bt_quickfix(curbuf)) || !usable_win)
+    {
+	if (qf_open_new_file_win(ll_ref) != OK)
+	    return FAIL;
+	*opened_window = TRUE;	/* close it when fail */
+    }
+    else
+    {
+	if (curwin->w_llist_ref != NULL)	/* In a location window */
+	    qf_goto_win_with_ll_file(usable_win_ptr, qf_fnum, ll_ref);
+	else					/* In a quickfix window */
+	    qf_goto_win_with_qfl_file(qf_fnum);
     }
 
     return OK;
@@ -2562,8 +2635,8 @@ qf_jump_edit_buffer(
 }
 
 /*
- * Goto the error line in the current file using either line/column number or a
+ * Go to the error line in the current file using either line/column number or
- * search pattern.
+ * a search pattern.
  */
     static void
 qf_jump_goto_line(
@@ -5779,7 +5852,7 @@ qf_setprop_context(qf_info_T *qi, int qf_idx, dictitem_T *di)
 /*
  * Set quickfix/location list properties (title, items, context).
  * Also used to add items from parsing a list of lines.
- * Used by the setqflist() and setloclist() VimL functions.
+ * Used by the setqflist() and setloclist() Vim script functions.
  */
     static int
 qf_set_properties(qf_info_T *qi, dict_T *what, int action, char_u *title)
@@ -6162,9 +6235,7 @@ hgr_get_ll(int *new_ll)
 	wp = curwin;
     else
 	/* Find an existing help window */
-	FOR_ALL_WINDOWS(wp)
+	wp = qf_find_help_win();
-	    if (bt_help(wp->w_buffer))
-		break;
 
     if (wp == NULL)	    /* Help window not found */
 	qi = NULL;

src/version.c

@@ -761,6 +761,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1812,
 /**/
     1811,
 /**/