Ticket #3711: support color aliases in skin files.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>

doc/man/mc.1.in

@@ -3708,6 +3708,10 @@ Color pair definitions
 .\"Skins colors"
 .br
 .\"LINK2"
+Color and attribute aliases
+.\"Skins aliases"
+.br
+.\"LINK2"
 Draw lines
 .\"Skins lines"
 .br
@@ -3915,6 +3919,24 @@ Colors\&.
 .\"Colors"
 section.
 
+.\"NODE "  Skins aliases"
+.SH "  Color and attribute aliases"
+This optional section might define aliases for single colors (not color pairs)
+as well as combination of attributes; in other words, for semicolon\-separated
+fragments of parameters. Aliases can refer to other aliases as long as they
+don't form a loop.
+.PP
+Example:
+.br
+.nf
+[aliases]
+    myfavfg=green
+    myfavbg=black
+    myfavattr=bold+italic
+[core]
+    _default_=myfavfg;myfavbg;myfavattr
+.fi
+
 .\"NODE "  Skins lines"
 .SH "  Draw lines"
 Lines sets in section

lib/skin/colors.c

@@ -120,6 +120,61 @@ mc_skin_color_get_with_defaults (const gchar * group, const gchar * name)
 
 /* --------------------------------------------------------------------------------------------- */
 
+/* If an alias is found, alloc a new string for the resolved value and free the input parameter.
+   Otherwise it's a no-op returning the original string. */
+static gchar *
+mc_skin_color_look_up_alias (mc_skin_t * mc_skin, gchar * str)
+{
+    gchar *orig, *str2;
+    int hop = 0;
+
+    orig = g_strdup (str);
+    str2 = g_strdup (str);
+
+    while (TRUE)
+    {
+        gchar **values;
+        gsize items_count;
+
+        values = mc_config_get_string_list (mc_skin->config, "aliases", str, &items_count);
+        if (items_count != 1)
+        {
+            /* No such alias declaration found, that is, we've got the resolved value. */
+            g_strfreev (values);
+            g_free (str2);
+            g_free (orig);
+            return str;
+        }
+
+        g_free (str);
+        str = g_strdup (values[0]);
+        g_strfreev (values);
+
+        /* str2 resolves at half speed than str. This is used for loop detection. */
+        if (hop++ % 2 != 0)
+        {
+            values = mc_config_get_string_list (mc_skin->config, "aliases", str2, &items_count);
+            g_assert (items_count == 1);
+            g_free (str2);
+            str2 = g_strdup (values[0]);
+            g_strfreev (values);
+
+            if (strcmp (str, str2) == 0)
+            {
+                /* Loop detected. */
+                fprintf (stderr,
+                         "Loop detected while trying to resolve alias \"%s\" in skin \"%s\"\n",
+                         orig, mc_skin->name);
+                g_free (str);
+                g_free (str2);
+                return orig;
+            }
+        }
+    }
+}
+
+/* --------------------------------------------------------------------------------------------- */
+
 static mc_skin_color_t *
 mc_skin_color_get_from_ini_file (mc_skin_t * mc_skin, const gchar * group, const gchar * key)
 {
@@ -142,11 +197,14 @@ mc_skin_color_get_from_ini_file (mc_skin_t * mc_skin, const gchar * group, const
     }
 
     tmp = mc_skin_color_get_with_defaults (group, "_default_");
-    mc_skin_color->fgcolor = (items_count > 0 && values[0][0]) ? g_strstrip (g_strdup (values[0])) :
+    mc_skin_color->fgcolor = (items_count > 0 && values[0][0]) ?
+        mc_skin_color_look_up_alias (mc_skin, g_strstrip (g_strdup (values[0]))) :
         (tmp != NULL) ? g_strdup (tmp->fgcolor) : NULL;
-    mc_skin_color->bgcolor = (items_count > 1 && values[1][0]) ? g_strstrip (g_strdup (values[1])) :
+    mc_skin_color->bgcolor = (items_count > 1 && values[1][0]) ?
+        mc_skin_color_look_up_alias (mc_skin, g_strstrip (g_strdup (values[1]))) :
         (tmp != NULL) ? g_strdup (tmp->bgcolor) : NULL;
-    mc_skin_color->attrs = (items_count > 2 && values[2][0]) ? g_strstrip (g_strdup (values[2])) :
+    mc_skin_color->attrs = (items_count > 2 && values[2][0]) ?
+        mc_skin_color_look_up_alias (mc_skin, g_strstrip (g_strdup (values[2]))) :
         (tmp != NULL) ? g_strdup (tmp->attrs) : NULL;
 
     g_strfreev (values);
@@ -265,7 +323,7 @@ mc_skin_color_cache_init (void)
 static gboolean
 mc_skin_color_check_inisection (const gchar * group)
 {
-    return !((strcasecmp ("skin", group) == 0)
+    return !((strcasecmp ("skin", group) == 0) || (strcasecmp ("aliases", group) == 0)
              || (strcasecmp ("lines", group) == 0) || (strncasecmp ("widget-", group, 7) == 0));
 }
 

misc/skins/gray-green-purple256.ini

@@ -25,34 +25,41 @@
     dleftmiddle = ╟
     drightmiddle = ╢
 
+[aliases]
+    bgmain = gray22
+    bgbitdarker = gray21
+    bgdarker = gray20
+    main1 = rgb141
+    main2 = rgb303
+
 [core]
-    _default_ = black;gray22
+    _default_ = black;bgmain
-    selected = ;rgb141
+    selected = ;main1
-    marked = rgb303;;bold
+    marked = main2;;bold
-    markselect = rgb303;rgb141;bold
+    markselect = main2;main1;bold
-    gauge = ;rgb141
+    gauge = ;main1
     input =
     inputunchanged = gray
-    inputmark = ;rgb141
+    inputmark = ;main1
-    disabled = gray8;gray20
+    disabled = gray8;bgdarker
     reverse =
-    commandlinemark = ;rgb141
+    commandlinemark = ;main1
-    header = rgb303
+    header = main2
 
 [dialog]
-    _default_ = black;gray20
+    _default_ = black;bgdarker
-    dfocus = ;rgb141
+    dfocus = ;main1
-    dhotnormal = rgb303
+    dhotnormal = main2
-    dhotfocus = rgb303;rgb141
+    dhotfocus = main2;main1
-    dtitle = rgb303
+    dtitle = main2
 
 [error]
     # "white" might change color when going bold, so use "rgb555" instead
     _default_ = rgb555;rgb400;bold
-    errdfocus = ;rgb303
+    errdfocus = ;main2
-    errdhotnormal = rgb141
+    errdhotnormal = main1
-    errdhotfocus = rgb141;rgb303
+    errdhotfocus = main1;main2
-    errdtitle = rgb141
+    errdtitle = main1
 
 [filehighlight]
     directory =
@@ -72,60 +79,60 @@
     database = rgb421
 
 [menu]
-    _default_ = black;gray20
+    _default_ = black;bgdarker
-    menusel = ;rgb141
+    menusel = ;main1
-    menuhot = rgb303
+    menuhot = main2
-    menuhotsel = rgb303;rgb141
+    menuhotsel = main2;main1
     menuinactive =
 
 [popupmenu]
-    _default_ = black;gray20
+    _default_ = black;bgdarker
-    menusel = ;rgb141
+    menusel = ;main1
-    menutitle = rgb303
+    menutitle = main2
 
 [buttonbar]
-    hotkey = black;gray22
+    hotkey = black;bgmain
-    button = black;gray20
+    button = black;bgdarker
 
 [statusbar]
-    _default_ = black;gray20
+    _default_ = black;bgdarker
 
 [help]
-    _default_ = black;gray20
+    _default_ = black;bgdarker
     helpitalic = rgb020
     helpbold = rgb300
-    helplink = rgb303;;underline
+    helplink = main2;;underline
-    helpslink = gray20;rgb303
+    helpslink = bgdarker;main2
-    helptitle = rgb303
+    helptitle = main2
 
 [editor]
-    _default_ = black;gray22
+    _default_ = black;bgmain
     editbold = rgb400
-    editmarked = ;rgb141
+    editmarked = ;main1
-    editwhitespace = rgb400;gray20
+    editwhitespace = rgb400;bgdarker
-    editlinestate = ;gray20
+    editlinestate = ;bgdarker
     bookmark = ;rgb531
-    bookmarkfound = ;rgb303
+    bookmarkfound = ;main2
-    editrightmargin = rgb400;gray20
+    editrightmargin = rgb400;bgdarker
 #    editbg =
-    editframe = rgb303;
+    editframe = main2;
     editframeactive = black;
     editframedrag = rgb400;
     window-state-char = ↕
     window-close-char = ✕
 
 [viewer]
-    _default_ = black;gray22
+    _default_ = black;bgmain
     # "black" might change color when going bold, so use "rgb000" instead
     viewbold = rgb000;;bold
     viewunderline = ;;underline
-    viewselected = rgb303;rgb141;bold
+    viewselected = main2;main1;bold
 
 [diffviewer]
     added = ;rgb340
-    changedline = ;gray20
+    changedline = ;bgdarker
-    changednew = rgb303;gray20
+    changednew = main2;bgdarker
-    changed = ;gray21
+    changed = ;bgbitdarker
     removed = ;rgb511
     # "white" might change color when going bold, so use "rgb555" instead
     error = rgb555;rgb400;bold

misc/skins/gray-orange-blue256.ini

@@ -25,34 +25,41 @@
     dleftmiddle = ╟
     drightmiddle = ╢
 
+[aliases]
+    bgmain = gray22
+    bgbitdarker = gray21
+    bgdarker = gray20
+    main1 = rgb530
+    main2 = rgb004
+
 [core]
-    _default_ = black;gray22
+    _default_ = black;bgmain
-    selected = ;rgb530
+    selected = ;main1
-    marked = rgb004;;bold
+    marked = main2;;bold
-    markselect = rgb004;rgb530;bold
+    markselect = main2;main1;bold
-    gauge = ;rgb530
+    gauge = ;main1
     input =
     inputunchanged = gray
-    inputmark = ;rgb530
+    inputmark = ;main1
-    disabled = gray8;gray20
+    disabled = gray8;bgdarker
     reverse =
-    commandlinemark = ;rgb530
+    commandlinemark = ;main1
-    header = rgb004
+    header = main2
 
 [dialog]
-    _default_ = black;gray20
+    _default_ = black;bgdarker
-    dfocus = ;rgb530
+    dfocus = ;main1
-    dhotnormal = rgb004
+    dhotnormal = main2
-    dhotfocus = rgb004;rgb530
+    dhotfocus = main2;main1
-    dtitle = rgb004
+    dtitle = main2
 
 [error]
     # "white" might change color when going bold, so use "rgb555" instead
     _default_ = rgb555;rgb400;bold
-    errdfocus = ;rgb004
+    errdfocus = ;main2
-    errdhotnormal = rgb530
+    errdhotnormal = main1
-    errdhotfocus = rgb530;rgb004
+    errdhotfocus = main1;main2
-    errdtitle = rgb530
+    errdtitle = main1
 
 [filehighlight]
     directory =
@@ -72,60 +79,60 @@
     database = rgb421
 
 [menu]
-    _default_ = black;gray20
+    _default_ = black;bgdarker
-    menusel = ;rgb530
+    menusel = ;main1
-    menuhot = rgb004
+    menuhot = main2
-    menuhotsel = rgb004;rgb530
+    menuhotsel = main2;main1
     menuinactive =
 
 [popupmenu]
-    _default_ = black;gray20
+    _default_ = black;bgdarker
-    menusel = ;rgb530
+    menusel = ;main1
-    menutitle = rgb004
+    menutitle = main2
 
 [buttonbar]
-    hotkey = black;gray22
+    hotkey = black;bgmain
-    button = black;gray20
+    button = black;bgdarker
 
 [statusbar]
-    _default_ = black;gray20
+    _default_ = black;bgdarker
 
 [help]
-    _default_ = black;gray20
+    _default_ = black;bgdarker
     helpitalic = rgb020
     helpbold = rgb300
-    helplink = rgb004;;underline
+    helplink = main2;;underline
-    helpslink = gray20;rgb004
+    helpslink = bgdarker;main2
-    helptitle = rgb004
+    helptitle = main2
 
 [editor]
-    _default_ = black;gray22
+    _default_ = black;bgmain
     editbold = rgb400
-    editmarked = ;rgb530
+    editmarked = ;main1
-    editwhitespace = rgb400;gray20
+    editwhitespace = rgb400;bgdarker
-    editlinestate = ;gray20
+    editlinestate = ;bgdarker
     bookmark = ;rgb531
-    bookmarkfound = ;rgb004
+    bookmarkfound = ;main2
-    editrightmargin = rgb400;gray20
+    editrightmargin = rgb400;bgdarker
 #    editbg =
-    editframe = rgb004;
+    editframe = main2;
     editframeactive = black;
     editframedrag = rgb400;
     window-state-char = ↕
     window-close-char = ✕
 
 [viewer]
-    _default_ = black;gray22
+    _default_ = black;bgmain
     # "black" might change color when going bold, so use "rgb000" instead
     viewbold = rgb000;;bold
     viewunderline = ;;underline
-    viewselected = rgb004;rgb530;bold
+    viewselected = main2;main1;bold
 
 [diffviewer]
     added = ;rgb340
-    changedline = ;gray20
+    changedline = ;bgdarker
-    changednew = rgb004;gray20
+    changednew = main2;bgdarker
-    changed = ;gray21
+    changed = ;bgbitdarker
     removed = ;rgb511
     # "white" might change color when going bold, so use "rgb555" instead
     error = rgb555;rgb400;bold