Use a steady clock source for progress reporting

Clock changes while apt is running can result in strange reports
confusing (and amusing) users. Sadly, to keep the ABI for now the
code is a bit more ugly than it would need to be.

1 files changed, 12 insertions, 5 deletions

diff --git a/apt-pkg/contrib/progress.cc b/apt-pkg/contrib/progress.cc
index 3bccc48d4..806bd47f8 100644
--- a/apt-pkg/contrib/progress.cc
+++ b/apt-pkg/contrib/progress.cc
@@ -14,6 +14,7 @@
 #include <apt-pkg/progress.h>
 
 #include <cmath>
+#include <chrono>
 #include <cstring>
 #include <iostream>
 #include <string>
@@ -115,12 +116,18 @@ bool OpProgress::CheckChange(float Interval)
       return false;
    
    // Check time delta
-   struct timeval Now;
-   gettimeofday(&Now,0);
-   decltype(Interval) const Diff = Now.tv_sec - LastTime.tv_sec + (Now.tv_usec - LastTime.tv_usec)/1000000.0;
-   if (Diff < Interval)
+   auto const Now = std::chrono::steady_clock::now().time_since_epoch();
+   auto const Now_sec = std::chrono::duration_cast<std::chrono::seconds>(Now);
+   auto const Now_usec = std::chrono::duration_cast<std::chrono::microseconds>(Now - Now_sec);
+   struct timeval NowTime = { Now_sec.count(), Now_usec.count() };
+
+   std::chrono::duration<decltype(Interval)> Delta =
+      std::chrono::seconds(NowTime.tv_sec - LastTime.tv_sec) +
+      std::chrono::microseconds(NowTime.tv_sec - LastTime.tv_usec);
+
+   if (Delta.count() < Interval)
       return false;
-   LastTime = Now;   
+   LastTime = NowTime;
    return true;
 }
 									/*}}}*/