added help function via html if yelp is not installed

The current help system requires yelp to be installed. This patch
will fallback to local html help and then internet html help via
http://www.gnu.org/software/pspp if no html is installed. The browser
is invoked via open (MAC), start (windows) and xdg-open (linux)

diff --git a/src/ui/gui/help-menu.c b/src/ui/gui/help-menu.c
index 61b9140d1e5e11b0e400b88f62d171188950659e..a5e533bd6ecbc66d5720514c9fd6e8d6a044aa51 100644 (file)
--- a/src/ui/gui/help-menu.c
+++ b/src/ui/gui/help-menu.c
@@ -1,5 +1,5 @@
 /* PSPPIRE - a graphical user interface for PSPP.
-   Copyright (C) 2006, 2007, 2010, 2011, 2012, 2013, 2015  Free Software Foundation
+   Copyright (C) 2006, 2007, 2010, 2011, 2012, 2013, 2015, 2016  Free Software Foundation
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -31,6 +31,13 @@
 #define _(msgid) gettext (msgid)
 #define N_(msgid) msgid
 
+#ifdef __APPLE__
+#define HTMLOPENAPP "open"
+#elif  _WIN32
+#define HTMLOPENAPP "start"
+#else
+#define HTMLOPENAPP "xdg-open"
+#endif
 
 static const gchar *artists[] = { "Bastián Díaz", "Hugo Alejandro", NULL};
 
@@ -85,27 +92,62 @@ void
 online_help (const char *page)
 {
   GError *err = NULL;
-  gchar *cmd = NULL;
-
+  GError *htmlerr = NULL;
   gchar *argv[3] = { "yelp", 0, 0};
+  gchar *htmlargv[3] = { HTMLOPENAPP, 0, 0};
+  gchar *htmlfilename = NULL;
+  gchar *htmlfullname = NULL;
 
   if (page == NULL)
-    argv[1] = g_strdup_printf ("file://%s", relocate (DOCDIR "/pspp.xml"));
+    {
+      argv[1] = g_strdup_printf ("file://%s", relocate (DOCDIR "/pspp.xml"));
+      htmlfilename = g_strdup ("index.html");
+      htmlargv[1] = g_strdup_printf ("file://%s", htmlfilename);
+    }
   else
-    argv[1] = g_strdup_printf ("file://%s#%s", relocate (DOCDIR "/pspp.xml"), page);
+    {
+      gchar **tokens = NULL;
+      const int maxtokens = 5;
+      int idx = 0;
+      argv[1] = g_strdup_printf ("file://%s#%s",
+                                 relocate (DOCDIR "/pspp.xml"), page);
+      tokens = g_strsplit (page, "#", maxtokens);
+      for(;tokens[idx] && idx < maxtokens;idx++);
+      htmlfilename = g_strdup_printf ("%s.html", tokens[idx-1]);
+      g_strfreev (tokens);
+    }
 
-  if (! g_spawn_async (NULL, argv,
-                      NULL, G_SPAWN_SEARCH_PATH,
-                      NULL, NULL,   NULL,   &err))
+  htmlfullname = g_strdup_printf ("%s/%s", relocate (DOCDIR "/pspp.html"),
+                                  htmlfilename);
+  if (g_file_test (relocate (DOCDIR "/pspp.html"), G_FILE_TEST_EXISTS))
+    htmlargv[1] = g_strdup_printf ("file://%s", htmlfullname);
+  else
+    htmlargv[1] = g_strdup_printf (PACKAGE_URL "manual/html_node/%s",
+                                   htmlfilename);
+
+  g_free (htmlfullname);
+  g_free (htmlfilename);
+
+  if (! (g_spawn_async (NULL, argv,
+                        NULL, G_SPAWN_SEARCH_PATH,
+                        NULL, NULL,   NULL,   &err) ||
+         g_spawn_async (NULL, htmlargv,
+                        NULL, G_SPAWN_SEARCH_PATH,
+                        NULL, NULL,   NULL,   &htmlerr))
+      )
     {
-      msg (ME, _("Cannot open reference manual: %s.  The PSPP user manual is "
-                 "also available at %s"),
+      msg (ME, _("Cannot open reference manual via yelp: %s. "
+                 "Cannot open via html: %s "
+                 "The PSSP manual is also available at %s"),
                   err->message,
+                  htmlerr->message,
                   PACKAGE_URL "documentation.html");
     }
 
-  g_free (cmd);
+  g_free (argv[1]);
+  g_free (htmlargv[1]);
   g_clear_error (&err);
+  g_clear_error (&htmlerr);
 }
 
 static void