9 files changed, 36 insertions, 13 deletions

diff --git a/defines.hpp b/defines.hpp
index 72993aca54..fcaa00f1d4 100644
--- a/defines.hpp
+++ b/defines.hpp
@@ -2,6 +2,7 @@
 
 #define DATA_FILE_EXTENSION ".mwm"
 #define DATA_FILE_EXTENSION_TMP ".mwm.tmp"
+#define DIFF_FILE_EXTENSION ".mwmdiff"
 #define FONT_FILE_EXTENSION ".ttf"
 #define OSM2FEATURE_FILE_EXTENSION ".osm2ft"
 #define EXTENSION_TMP ".tmp"
diff --git a/platform/country_defines.cpp b/platform/country_defines.cpp
index bbbf933a2a..4f1072a466 100644
--- a/platform/country_defines.cpp
+++ b/platform/country_defines.cpp
@@ -40,5 +40,7 @@ string DebugPrint(MapOptions options)
       return "CarRouting";
     case MapOptions::MapWithCarRouting:
       return "MapWithCarRouting";
+    case MapOptions::Diff:
+      return "Diff";
   }
 }
diff --git a/platform/country_defines.hpp b/platform/country_defines.hpp
index c59d63759b..e9a123bc8a 100644
--- a/platform/country_defines.hpp
+++ b/platform/country_defines.hpp
@@ -8,7 +8,8 @@ enum class MapOptions : uint8_t
   Nothing = 0x0,
   Map = 0x1,
   CarRouting = 0x2,
-  MapWithCarRouting = 0x3
+  MapWithCarRouting = 0x3,
+  Diff = 0x4
 };
 
 using TMwmCounter = uint32_t;
diff --git a/platform/country_file.cpp b/platform/country_file.cpp
index f013ba92b8..2910e68d2b 100644
--- a/platform/country_file.cpp
+++ b/platform/country_file.cpp
@@ -20,6 +20,8 @@ string GetNameWithExt(string const & countryFile, MapOptions file)
       return countryFile + DATA_FILE_EXTENSION;
     case MapOptions::CarRouting:
       return countryFile + DATA_FILE_EXTENSION + ROUTING_FILE_EXTENSION;
+    case MapOptions::Diff:
+      return countryFile + DIFF_FILE_EXTENSION;
     default:
       ASSERT(false, ("Can't get name for:", file));
       return string();
@@ -51,11 +53,12 @@ TMwmSize CountryFile::GetRemoteSize(MapOptions filesMask) const
   return size;
 }
 
-
 string GetFileName(string const & countryFile, MapOptions opt, int64_t version)
 {
-  return version::IsSingleMwm(version) ? GetNameWithExt(countryFile, MapOptions::Map)
-                                       : GetNameWithExt(countryFile, opt);
+  if (version::IsSingleMwm(version))
+    opt = opt == MapOptions::Diff ? MapOptions::Diff : MapOptions::Map;
+
+  return GetNameWithExt(countryFile, opt);
 }
 
 string DebugPrint(CountryFile const & file)
diff --git a/platform/country_file.hpp b/platform/country_file.hpp
index 06a3286155..c7f253ce5d 100644
--- a/platform/country_file.hpp
+++ b/platform/country_file.hpp
@@ -32,8 +32,8 @@ private:
 
   /// Base name (without any extensions) of the file. Same as id of country/region.
   string m_name;
-  TMwmSize m_mapSize;
-  TMwmSize m_routingSize;
+  TMwmSize m_mapSize = 0;
+  TMwmSize m_routingSize = 0;
 };
 
 /// \returns This method returns file name with extension. For example Abkhazia.mwm or
diff --git a/platform/local_country_file.cpp b/platform/local_country_file.cpp
index a69c7439e0..40a63fe105 100644
--- a/platform/local_country_file.cpp
+++ b/platform/local_country_file.cpp
@@ -35,6 +35,12 @@ void LocalCountryFile::SyncWithDisk()
   m_routingSize = 0;
   Platform & platform = GetPlatform();
 
+  if (platform.GetFileSizeByFullPath(GetPath(MapOptions::Diff), m_mapSize))
+  {
+    m_files = SetOptions(m_files, MapOptions::Diff);
+    return;
+  }
+
   if (platform.GetFileSizeByFullPath(GetPath(MapOptions::Map), m_mapSize))
     m_files = SetOptions(m_files, MapOptions::Map);
 
@@ -53,7 +59,7 @@ void LocalCountryFile::SyncWithDisk()
 void LocalCountryFile::DeleteFromDisk(MapOptions files) const
 {
   vector<MapOptions> const mapOptions =
-      version::IsSingleMwm(GetVersion()) ? vector<MapOptions>({MapOptions::Map})
+      version::IsSingleMwm(GetVersion()) ? vector<MapOptions>({MapOptions::Map, MapOptions::Diff})
                                          : vector<MapOptions>({MapOptions::Map, MapOptions::CarRouting});
   for (MapOptions file : mapOptions)
   {
diff --git a/platform/local_country_file.hpp b/platform/local_country_file.hpp
index e506a72f0e..cebf6b55cd 100644
--- a/platform/local_country_file.hpp
+++ b/platform/local_country_file.hpp
@@ -55,20 +55,21 @@ public:
 
   // Returns a mask of all known country files. Return value may be
   // empty until SyncWithDisk() is called.
-  inline MapOptions GetFiles() const { return m_files; }
+  MapOptions GetFiles() const { return m_files; }
 
   // Checks whether files specified in filesMask are on disk. Return
   // value will be false until SyncWithDisk() is called.
-  inline bool OnDisk(MapOptions filesMask) const
+  bool OnDisk(MapOptions filesMask) const
   {
     return (static_cast<unsigned>(m_files) & static_cast<unsigned>(filesMask)) ==
            static_cast<unsigned>(filesMask);
   }
 
-  inline string const & GetDirectory() const { return m_directory; }
-  inline string const & GetCountryName() const { return m_countryFile.GetName(); }
-  inline int64_t GetVersion() const { return m_version; }
-  inline CountryFile const & GetCountryFile() const { return m_countryFile; }
+  string const & GetDirectory() const { return m_directory; }
+  string const & GetCountryName() const { return m_countryFile.GetName(); }
+  int64_t GetVersion() const { return m_version; }
+  CountryFile const & GetCountryFile() const { return m_countryFile; }
+  CountryFile & GetCountryFile() { return m_countryFile; }
 
   bool operator<(LocalCountryFile const & rhs) const;
   bool operator==(LocalCountryFile const & rhs) const;
diff --git a/storage/queued_country.cpp b/storage/queued_country.cpp
index d1e73015ab..22a3aa0fb3 100644
--- a/storage/queued_country.cpp
+++ b/storage/queued_country.cpp
@@ -39,6 +39,13 @@ void QueuedCountry::RemoveOptions(MapOptions opt)
     m_current = LeastSignificantOption(m_left);
 }
 
+void QueuedCountry::ResetToDefaultOptions()
+{
+  m_init = MapOptions::MapWithCarRouting;
+  m_left = MapOptions::MapWithCarRouting;
+  m_current = LeastSignificantOption(m_left);
+}
+
 bool QueuedCountry::SwitchToNextFile()
 {
   ASSERT(HasOptions(m_left, m_current),
diff --git a/storage/queued_country.hpp b/storage/queued_country.hpp
index 9597723de1..0747fe018d 100644
--- a/storage/queued_country.hpp
+++ b/storage/queued_country.hpp
@@ -16,6 +16,8 @@ public:
 
   void AddOptions(MapOptions opt);
   void RemoveOptions(MapOptions opt);
+  /// In case we can't update file using diff scheme.
+  void ResetToDefaultOptions();
   bool SwitchToNextFile();
 
   inline TCountryId const & GetCountryId() const { return m_countryId; }