diff --git a/src/cache_manager.cc b/src/cache_manager.cc
index a276f765..cf21a545 100644
--- a/src/cache_manager.cc
+++ b/src/cache_manager.cc
@@ -136,9 +136,5 @@ void WriteToCache(Config* config, IndexFile& file) {
   }
 
   std::string indexed_content = Serialize(file);
-  std::ofstream cache;
-  cache.open(cache_basename + ".json");
-  assert(cache.good());
-  cache << indexed_content;
-  cache.close();
+  WriteToFile(cache_basename + ".json", indexed_content);
 }
diff --git a/src/utils.cc b/src/utils.cc
index f165a572..c98658ac 100644
--- a/src/utils.cc
+++ b/src/utils.cc
@@ -462,7 +462,9 @@ void Fail(const std::string& message) {
 }
 
 void WriteToFile(const std::string& filename, const std::string& content) {
-  std::ofstream file(filename);
+  std::ofstream file(filename,
+                     std::ios::out | std::ios::trunc | std::ios::binary);
+  assert(file.good());
   file << content;
 }