[coding][android]: Use native function to move files

The previous implementation of StoragePathManager.changeStorage()
tried to move files from one volume to another using MoveFileX().
MoveFileX() was just a thin wrapper around rename(2), thus it failed
in 100% of cases and a slow Java CopyFile() fallback was called instead.

- Rewrite MoveFileX to actually move files instead of renaming.
- Don't call the slow Java fallback code.
- Create directories before trying to move files there, not after.

Signed-off-by: Roman Tsisyk <roman@tsisyk.com>

android/src/com/mapswithme/maps/settings/StoragePathManager.java

@@ -382,19 +382,17 @@ public class StoragePathManager
     {
       for (int i = 0; i < oldFiles.length; ++i)
       {
-        if (MapManager.nativeMoveFile(oldFiles[i].getAbsolutePath(), newFiles[i].getAbsolutePath()))
+        File parent = newFiles[i].getParentFile();
+        if (parent != null)
+          parent.mkdirs();
+        if (!MapManager.nativeMoveFile(oldFiles[i].getAbsolutePath(), newFiles[i].getAbsolutePath()))
         {
-          // No need to delete oldFiles[i] because it was moved to newFiles[i].
-          oldFiles[i] = null;
-        } else
-        {
-          File parent = newFiles[i].getParentFile();
-          if (parent != null)
-            parent.mkdirs();
-          StorageUtils.copyFile(oldFiles[i], newFiles[i]);
+          throw new IOException("Failed to move " + oldFiles[i].getAbsolutePath() + " to " + newFiles[i]
+              .getAbsolutePath());
         }
       }
-    } catch (IOException e)
+    }
+    catch (IOException e)
     {
       e.printStackTrace();
       // In the case of failure delete all new files.  Old files will

coding/internal/file_data.cpp

@@ -195,6 +195,23 @@ bool RenameFileX(string const & fOld, string const & fNew)
   return CheckFileOperationResult(res, fOld);
 }
 
+bool MoveFileX(string const & fOld, string const & fNew)
+{
+  // Try to rename the file first.
+  int res = rename(fOld.c_str(), fNew.c_str());
+  if (res == 0)
+    return true;
+
+  // Otherwise perform the full move.
+  if (!CopyFileX(fOld, fNew))
+  {
+    (void) DeleteFileX(fNew);
+    return false;
+  }
+  (void) DeleteFileX(fOld);
+  return true;
+}
+
 bool WriteToTempAndRenameToFile(string const & dest, function<bool(string const &)> const & write,
                                 string const & tmp)
 {
@@ -232,33 +249,22 @@ void AppendFileToFile(string const & fromFilename, string const & toFilename)
 
 bool CopyFileX(string const & fOld, string const & fNew)
 {
+  ifstream ifs;
+  ofstream ofs;
+  ifs.exceptions(ifstream::failbit | ifstream::badbit);
+  ofs.exceptions(ifstream::failbit | ifstream::badbit);
+
   try
   {
-    ifstream ifs(fOld.c_str());
-    ofstream ofs(fNew.c_str());
-
-    if (ifs.is_open() && ofs.is_open())
-    {
-      if (ifs.peek() == ifstream::traits_type::eof())
-        return true;
-
-      ofs << ifs.rdbuf();
-      ofs.flush();
-
-      if (ofs.fail())
-      {
-        LOG(LWARNING, ("Bad or Fail bit is set while writing file:", fNew));
-        return false;
-      }
-
-      return true;
-    }
-    else
-      LOG(LERROR, ("Can't open files:", fOld, fNew));
+    ifs.open(fOld.c_str());
+    ofs.open(fNew.c_str());
+    ofs << ifs.rdbuf();
+    ofs.flush();
+    return true;
   }
   catch (exception const & ex)
   {
-    LOG(LERROR, ("Copy file error:", ex.what()));
+    LOG(LERROR, ("Failed to copy file from", fOld, "to", fNew, ":", strerror(errno)));
   }
 
   return false;

coding/internal/file_data.hpp

@@ -58,7 +58,9 @@ bool WriteToTempAndRenameToFile(std::string const & dest,
 
 void AppendFileToFile(std::string const & fromFilename, std::string const & toFilename);
 
-/// @return false if copy fails. DO NOT THROWS exceptions
+/// @return false if copy fails. DOES NOT THROWS exceptions
 bool CopyFileX(std::string const & fOld, std::string const & fNew);
+/// @return false if moving fails. DOES NOT THROW exceptions
+bool MoveFileX(std::string const & fOld, std::string const & fNew);
 bool IsEqualFiles(std::string const & firstFile, std::string const & secondFile);
 }  // namespace base