DoAutomaticFreeDiskSpaceControl() introduced

platform.cc

Index: platform.cc
diff --git a/platform.cc b/platform.cc
index 35d0cdd690f3bbbc17ac910097adeb44fe671f8e..071e06a3b30937828fa8ad9734ccde1da3884715 100644
--- a/platform.cc
+++ b/platform.cc
@@ -12,6 +12,7 @@
 #include <signal.h>
 #include <sys/mount.h>
 #include <sys/stat.h>
+#include <sys/statvfs.h>
 #include <sys/types.h>
 
 #include <base/file_util.h>
@@ -366,6 +367,14 @@ bool Platform::GetUserId(const std::string& user, uid_t* user_id,
   return true;
 }
 
+int64 Platform::AmountOfFreeDiskSpace(const string& path) {
+  struct statvfs stats;
+  if (statvfs(path.c_str(), &stats) != 0) {
+    return -1;
+  }
+  return static_cast<int64>(stats.f_bavail) * stats.f_frsize;
+}
+
 void Platform::ClearUserKeyring() {
   keyctl(KEYCTL_CLEAR, KEY_SPEC_USER_KEYRING);
 }