Introduce readCategoriesFromFeed()

Added a function to load categories stored in an OPDS stream

include/tools.h

@@ -28,6 +28,7 @@
 namespace kiwix {
 typedef std::pair<std::string, std::string> LangNameCodePair;
 typedef std::vector<LangNameCodePair> FeedLanguages;
+typedef std::vector<std::string> FeedCategories;
 
 /**
  * Return the current directory.
@@ -235,5 +236,13 @@ std::string beautifyFileSize(uint64_t number);
  * @return vector containing pairs of language code and their corresponding full language name. 
  */
 FeedLanguages readLanguagesFromFeed(const std::string& content);
+
+/**
+ * Load categories stored in an OPDS stream .
+ * 
+ * @param content the OPDS stream.
+ * @return vector containing category strings.
+ */
+FeedCategories readCategoriesFromFeed(const std::string& content);
 }
 #endif // KIWIX_TOOLS_H

src/tools/opdsParsingTools.cpp

@@ -22,6 +22,20 @@ FeedLanguages parseLanguages(const pugi::xml_document& doc)
     return langs;
 }
 
+FeedCategories parseCategories(const pugi::xml_document& doc)
+{
+    pugi::xml_node feedNode = doc.child("feed");
+    FeedCategories categories;
+
+    for (pugi::xml_node entryNode = feedNode.child("entry"); entryNode;
+        entryNode = entryNode.next_sibling("entry")) {
+            auto title = VALUE("title");
+            categories.push_back(title);
+    }
+
+    return categories;
+}
+
 } // unnamed namespace
 
 FeedLanguages readLanguagesFromFeed(const std::string& content)
@@ -38,4 +52,19 @@ FeedLanguages readLanguagesFromFeed(const std::string& content)
     return FeedLanguages();
 }
 
+FeedCategories readCategoriesFromFeed(const std::string& content)
+{
+    pugi::xml_document doc;
+    pugi::xml_parse_result result
+        = doc.load_buffer((void*)content.data(), content.size());
+
+    FeedCategories categories;
+    if (result) {
+        categories = parseCategories(doc);
+        return categories;
+    }
+
+    return categories;
+}
+
 } // namespace kiwix