android: Add simple utility class to generate settings_t compatible config snippets

diff --git a/src/frontends/android/src/org/strongswan/android/utils/SettingsWriter.java b/src/frontends/android/src/org/strongswan/android/utils/SettingsWriter.java
new file mode 100644 (file)
index 0000000..01c0ab8
--- /dev/null
+++ b/src/frontends/android/src/org/strongswan/android/utils/SettingsWriter.java
@@ -0,0 +1,160 @@
+/*
+ * Copyright (C) 2015 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * 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.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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.
+ */
+
+package org.strongswan.android.utils;
+
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map.Entry;
+import java.util.regex.Pattern;
+
+
+/**
+ * Simple generator for data/files that may be parsed by libstrongswan's
+ * settings_t class.
+ */
+public class SettingsWriter
+{
+       /**
+        * Top-level section
+        */
+       private final SettingsSection mTop = new SettingsSection();
+
+       /**
+        * Set a string value
+        * @param key
+        * @param value
+        * @return the writer
+        */
+       public SettingsWriter setValue(String key, String value)
+       {
+               Pattern pattern = Pattern.compile("[^#{}=\"\\n\\t ]+");
+               if (key == null || !pattern.matcher(key).matches())
+               {
+                       return this;
+               }
+               String[] keys = key.split("\\.");
+               SettingsSection section = mTop;
+               section = findOrCreateSection(Arrays.copyOfRange(keys, 0, keys.length-1));
+               section.Settings.put(keys[keys.length-1], value);
+               return this;
+       }
+
+       /**
+        * Set an integer value
+        * @param key
+        * @param value
+        * @return the writer
+        */
+       public SettingsWriter setValue(String key, Integer value)
+       {
+               return setValue(key, value == null ? null : value.toString());
+       }
+
+       /**
+        * Set a boolean value
+        * @param key
+        * @param value
+        * @return the writer
+        */
+       public SettingsWriter setValue(String key, Boolean value)
+       {
+               return setValue(key, value == null ? null : value ? "1" : "0");
+       }
+
+       /**
+        * Serializes the settings to a string in the format understood by
+        * libstrongswan's settings_t parser.
+        * @return serialized settings
+        */
+       public String serialize()
+       {
+               StringBuilder builder = new StringBuilder();
+               serializeSection(mTop, builder);
+               return builder.toString();
+       }
+
+       /**
+        * Serialize the settings in a section and recursively serialize sub-sections
+        * @param section
+        * @param builder
+        */
+       private void serializeSection(SettingsSection section, StringBuilder builder)
+       {
+               for (Entry<String, String> setting : section.Settings.entrySet())
+               {
+                       builder.append(setting.getKey()).append('=');
+                       if (setting.getValue() != null)
+                       {
+                               builder.append("\"").append(escapeValue(setting.getValue())).append("\"");
+                       }
+                       builder.append('\n');
+               }
+
+               for (Entry<String, SettingsSection> subsection : section.Sections.entrySet())
+               {
+                       builder.append(subsection.getKey()).append(" {\n");
+                       serializeSection(subsection.getValue(), builder);
+                       builder.append("}\n");
+               }
+       }
+
+       /**
+        * Escape value so it may be wrapped in "
+        * @param value
+        * @return
+        */
+       private String escapeValue(String value)
+       {
+               return value.replace("\"", "\\\"");
+       }
+
+       /**
+        * Find or create the nested sections with the given names
+        * @param sections list of section names
+        * @return final section
+        */
+       private SettingsSection findOrCreateSection(String[] sections)
+       {
+               SettingsSection section = mTop;
+               for (String name : sections)
+               {
+                       SettingsSection subsection = section.Sections.get(name);
+                       if (subsection == null)
+                       {
+                               subsection = new SettingsSection();
+                               section.Sections.put(name, subsection);
+                       }
+                       section = subsection;
+               }
+               return section;
+       }
+
+       /**
+        * A section containing sub-sections and settings.
+        */
+       private class SettingsSection
+       {
+               /**
+                * Assigned key/value pairs
+                */
+               LinkedHashMap<String,String> Settings = new LinkedHashMap<String, String>();
+
+               /**
+                * Assigned sub-sections
+                */
+               LinkedHashMap<String,SettingsSection> Sections = new LinkedHashMap<String, SettingsWriter.SettingsSection>();
+       }
+}