1 files changed, 137 insertions, 0 deletions
diff --git a/app/wlib/gtklib/browserhelp.c b/app/wlib/gtklib/browserhelp.c
new file mode 100644
index 0000000..9351e86
--- /dev/null
+++ b/app/wlib/gtklib/browserhelp.c
@@ -0,0 +1,137 @@
+/** \file browserhelp.c
+ * use the default browser based help
+ */
+
+/*  XTrkCad - Model Railroad CAD
+ *  Copyright (C) 2015 Martin Fischer
+ *
+ *  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
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <stdlib.h>
+#include <assert.h>
+
+#include "gtkint.h"
+#include "i18n.h"
+
+#include "dynstring.h"
+
+#define DEFAULTBROWSERCOMMAND "xdg-open"
+
+#define  HELPERRORTEXT 			"Help Error - help information can not be found.\n" \
+								"The help information you requested cannot be shown.\n" \
+								"Usually this is an installation problem, Make sure that a default browser" \
+                                " is configured and that XTrackCAD and the included " \
+								"HTML files are installed properly and can be found via the XTRKCADLIB environment " \
+								"variable.\n Also make sure that the user has sufficient access rights to read these" \
+ 								"files."
+/**
+ * Create a fully qualified url froma topic
+ *
+ * \param helpUrl OUT pointer to url, free by caller
+ * \param topic IN the help topic
+ */
+
+static void
+TopicToUrl(char **helpUrl, const char *topic)
+{
+    DynString url;
+    DynStringMalloc(&url, 16);
+
+    // build up the url line
+    DynStringCatCStrs(&url,
+                      "file://",
+                      wGetAppLibDir(),
+                      "/html/",
+                      topic,
+                      ".html",
+                      NULL);
+
+    *helpUrl = strdup(DynStringToCStr(&url));
+    DynStringFree(&url);
+}
+/**
+ * Extend the PATH variable inthe environment to include XTrackCAD's
+ * script directory.
+ *
+ * \return pointer to old path
+ */
+
+static char *
+ExtendPath(void)
+{
+    char *path = getenv("PATH");
+    DynString newPath;
+    DynStringMalloc(&newPath, 16);
+
+    // append XTrackCAD's directory to the path as a fallback
+    DynStringCatCStrs(&newPath,
+                      path,
+                      ":",
+                      wGetAppLibDir(),
+                      NULL);
+
+    setenv("PATH",
+           DynStringToCStr(&newPath),
+           TRUE);
+
+    DynStringFree(&newPath);
+
+    return (path);
+}
+
+/**
+ * Invoke the system's default browser to display help for <topic>. First the
+ * system's standard xdg-open command is attempted. If that is not available, the
+ * version included with the XTrackCAD installation is executed.
+ *
+ * \param topic IN topic string
+ */
+
+void wHelp(const char * topic)
+{
+    int rc;
+    char *url;
+    DynString commandLine;
+    char *currentPath;
+
+    assert(topic != NULL);
+    assert(strlen(topic));
+
+    currentPath = ExtendPath();
+    TopicToUrl(&url, topic);
+
+    DynStringMalloc(&commandLine, 16);
+    DynStringCatCStrs(&commandLine,
+                      DEFAULTBROWSERCOMMAND,
+                      " ",
+                      url,
+                      NULL);
+
+    // the command should be found via the PATH
+    rc = system(DynStringToCStr(&commandLine));
+
+    if (rc) {
+        wNotice(HELPERRORTEXT, _("Cancel"), NULL);
+    }
+
+    // restore the PATH
+    setenv("PATH",
+           currentPath,
+           TRUE);
+
+    free(url);
+    DynStringFree(&commandLine);
+}