Support multi-zims search in kiwix-lib.

All the code was already in zimlib.
It is mainly a update of the code using zimlib.

No JNI change for now to not break the API.

include/searcher.h

@@ -56,9 +56,11 @@ struct SearcherInternal;
 class Searcher
 {
  public:
+  Searcher();
   Searcher(const string& xapianDirectoryPath, Reader* reader);
   ~Searcher();
 
+  void add_reader(Reader* reader, const std::string& humanReaderName);
   void search(std::string& search,
               unsigned int resultStart,
               unsigned int resultEnd,
@@ -84,7 +86,8 @@ class Searcher
                      const unsigned int resultEnd,
                      const bool verbose = false);
 
-  Reader* reader;
+  std::vector<Reader*> readers;
+  std::vector<std::string> humanReaderNames;
   SearcherInternal* internal;
   std::string searchPattern;
   std::string protocolPrefix;

src/android/kiwix.cpp

@@ -490,7 +490,15 @@ JNIEXPORT jboolean JNICALL Java_org_kiwix_kiwixlib_JNIKiwix_loadFulltextIndex(
     if (searcher != NULL) {
       delete searcher;
     }
-    searcher = new kiwix::Searcher(cPath, reader);
+    if (!reader || !reader->hasFulltextIndex()) {
+      // Use old API (no embedded full text index).
+      searcher = new kiwix::Searcher(cPath, reader);
+    } else {
+      // Use the new API. We don't care about the human readable name as
+      // we don't use it (in android).
+      searcher = new kiwix::Searcher();
+      searcher->add_reader(reader, "");
+    }
   } catch (...) {
     searcher = NULL;
     retVal = JNI_FALSE;

src/searcher.cpp

@@ -74,8 +74,7 @@ struct SearcherInternal {
 
 /* Constructor */
 Searcher::Searcher(const string& xapianDirectoryPath, Reader* reader)
-    : reader(reader),
-      internal(new SearcherInternal()),
+    : internal(new SearcherInternal()),
       searchPattern(""),
       protocolPrefix("zim://"),
       searchProtocolPrefix("search://?"),
@@ -91,11 +90,32 @@ Searcher::Searcher(const string& xapianDirectoryPath, Reader* reader)
   }
 }
 
+Searcher::Searcher()
+    : internal(new SearcherInternal()),
+      searchPattern(""),
+      protocolPrefix("zim://"),
+      searchProtocolPrefix("search://?"),
+      resultCountPerPage(0),
+      estimatedResultCount(0),
+      resultStart(0),
+      resultEnd(0)
+{
+  template_ct2 = RESOURCE::results_ct2;
+  loadICUExternalTables();
+}
+
 /* Destructor */
 Searcher::~Searcher()
 {
   delete internal;
 }
+
+void Searcher::add_reader(Reader* reader, const std::string& humanReadableName)
+{
+  this->readers.push_back(reader);
+  this->humanReaderNames.push_back(humanReadableName);
+}
+
 /* Search strings in the database */
 void Searcher::search(std::string& search,
                       unsigned int resultStart,
@@ -135,8 +155,15 @@ void Searcher::search(std::string& search,
       this->estimatedResultCount
           = internal->_xapianSearcher->results.get_matches_estimated();
     } else {
-      internal->_search = this->reader->getZimFileHandler()->search(
-          unaccentedSearch, resultStart, resultEnd);
+      std::vector<const zim::File*> zims;
+      for (auto current = this->readers.begin(); current != this->readers.end();
+           current++) {
+        zims.push_back((*current)->getZimFileHandler());
+      }
+      zim::Search* search = new zim::Search(zims);
+      search->set_query(unaccentedSearch);
+      search->set_range(resultStart, resultEnd);
+      internal->_search = search;
       internal->current_iterator = internal->_search->begin();
       this->estimatedResultCount = internal->_search->get_matches_estimated();
     }
@@ -192,8 +219,16 @@ void Searcher::suggestions(std::string& search, const bool verbose)
      * We do not support that. */
     this->estimatedResultCount = 0;
   } else {
-    internal->_search = this->reader->getZimFileHandler()->suggestions(
-          unaccentedSearch, resultStart, resultEnd);
+    std::vector<const zim::File*> zims;
+    for (auto current = this->readers.begin(); current != this->readers.end();
+         current++) {
+      zims.push_back((*current)->getZimFileHandler());
+    }
+    zim::Search* search = new zim::Search(zims);
+    search->set_query(unaccentedSearch);
+    search->set_range(resultStart, resultEnd);
+    search->set_suggestion_mode(true);
+    internal->_search = search;
     internal->current_iterator = internal->_search->begin();
     this->estimatedResultCount = internal->_search->get_matches_estimated();
   }