Implemented getTermCompletions()

Author: veloman-yunkan

src/suggestion.cpp

@@ -297,11 +297,45 @@ struct TermWithFreq
   }
 };
 
-std::vector<TermWithFreq> getTermCompletions(const SuggestionDataBase& db,
-                                             const std::string& termPrefix)
+typedef std::vector<TermWithFreq> TermCollection;
+
+bool termShouldBeIncludedInAutoCompletions(const std::string& term) {
+  // XXX: implement properly (e.g. omit prefixed terms)
+  return true;
+}
+
+TermCollection getAllTerms(const SuggestionDataBase& db) {
+  TermCollection allTerms;
+
+  const Xapian::Database& titleDb = db.m_database;
+  for (auto it = titleDb.allterms_begin(); it != titleDb.allterms_end(); ++it) {
+    if ( termShouldBeIncludedInAutoCompletions(*it) ) {
+      allTerms.push_back(TermWithFreq{*it, it.get_termfreq()});
+    }
+  }
+
+  std::sort(allTerms.begin(), allTerms.end(), TermWithFreq::dictionaryPred);
+  return allTerms;
+}
+
+TermCollection getTermCompletions(const SuggestionDataBase& db,
+                                  const std::string& termPrefix)
 {
-  // XXX: implement properly
-  return {{"daily", 1}, {"data", 2}, {"date", 7}, { "day", 4}};
+  if ( !db.hasDatabase() ) {
+    return TermCollection();
+  }
+
+  const TermCollection allTerms = getAllTerms(db);
+  auto it = std::lower_bound(allTerms.begin(), allTerms.end(),
+                             TermWithFreq{termPrefix, 0},
+                             TermWithFreq::dictionaryPred);
+
+  TermCollection result;
+  for ( ; it != allTerms.end() && startsWith(it->term, termPrefix); ++it ) {
+    result.push_back(*it);
+  }
+
+  return result;
 }
 
 } // unnamed namespace

src/tools.h

@@ -52,6 +52,12 @@ namespace zim {
    **/
   uint32_t LIBZIM_PRIVATE_API randomNumber(uint32_t max);
 
+  inline bool startsWith(const std::string& str, const std::string& prefix)
+  {
+     return prefix.length() <= str.length()
+          && std::equal(prefix.begin(), prefix.end(), str.begin());
+  }
+
   std::vector<std::string> split(const std::string & str,
                                 const std::string & delims=" *-");
 

test/suggestion.cpp

@@ -783,6 +783,25 @@ TEST(Suggestion, autoCompletionAndSpellingCorrection) {
     {"Birth date of John Smith", "xx/xx/xx", "<b>Birth</b> date of John Smith"},
   }));
 
+  // Since the count of title suggestions will exceed the specified limit,
+  // autocompletion suggestions should be returned instead
+  EXPECT_SUGGESTION_RESULTS(archive, "bi", 4, ({
+    {"", "", "<b>big</b>" },
+    {"", "", "<b>birth</b>" },
+  }));
+
+  EXPECT_SUGGESTION_RESULTS(archive, "date bi", 10, ({
+    {"Date of my birth", "long_ago", "<b>Date</b> of my <b>birth</b>"},
+    {"J. Wales' birth date",   "1966/08/07", "J. Wales' <b>birth</b> <b>date</b>"},
+    {"Birth date of J. Christ", "-1/12/25" , "<b>Birth</b> <b>date</b> of J. Christ"},
+    {"Birth date of John Smith", "xx/xx/xx", "<b>Birth</b> <b>date</b> of John Smith"},
+  }));
+
+  EXPECT_SUGGESTION_RESULTS(archive, "date bi", 3, ({
+    {"", "", "date <b>big</b>" },
+    {"", "", "date <b>birth</b>" },
+  }));
+
   EXPECT_SUGGESTION_RESULTS(archive, "da", 20, ({
     {"Date palm"              , "Date_palm"  , "<b>Date</b> palm"             },
     {"Date, Fukushima"        , "Date_(city)", "<b>Date</b>, Fukushima"       },