Show absolute time while waiting for lock instead of %, rework message

Showing a percentage for a timeout is pretty non-standard. Rework the
progress class so it can show an absolute progress (currently hardcoded
to use seconds as a unit). If there is a timeout (aka if it's not the
maximum long long unsigned -1llu), then show the timeout, otherwise
just count up seconds, e.g.

Waiting for cache lock: Could not get lock /var/lib/dpkg/lock-frontend. It is held by process 33842 (apt)... 1/120s

or

Waiting for cache lock: Could not get lock /var/lib/dpkg/lock-frontend. It is held by process 33842 (apt)... 1s

Also improve the error message to use "Waiting for cache lock: %s" instead of "... (%s)", as having
multiple sentences inside parenthesis is super weird, as is having two closing parens.

We pass the information via _config, as that's reasonably easy and avoids
ABI hackage. It also provides an interesting debugging tool for other
kinds of progress.

2 files changed, 13 insertions, 4 deletions

diff --git a/apt-pkg/contrib/progress.cc b/apt-pkg/contrib/progress.cc
index 971198270..03f88d4ce 100644
--- a/apt-pkg/contrib/progress.cc
+++ b/apt-pkg/contrib/progress.cc
@@ -91,7 +91,10 @@ void OpProgress::SubProgress(unsigned long long SubTotal,const string &Op,
    an update the display would be swamped and the system much slower.
    This provides an upper bound on the update rate. */
 bool OpProgress::CheckChange(float Interval)
-{  
+{
+   // For absolute progress, we assume every call is relevant.
+   if (_config->FindB("APT::Internal::OpProgress::Absolute", false))
+      return true;
    // New major progress indication
    if (Op != LastOp)
    {
@@ -199,9 +202,14 @@ void OpTextProgress::Update()
       Write(S);
       cout << endl;
    }
-   
-   // Print the spinner
-   snprintf(S,sizeof(S),_("%c%s... %u%%"),'\r',Op.c_str(),(unsigned int)Percent);
+
+   // Print the spinner. Absolute progress shows us a time progress.
+   if (_config->FindB("APT::Internal::OpProgress::Absolute", false) && Total != -1llu)
+      snprintf(S, sizeof(S), _("%c%s... %llu/%llus"), '\r', Op.c_str(), Current, Total);
+   else if (_config->FindB("APT::Internal::OpProgress::Absolute", false))
+      snprintf(S, sizeof(S), _("%c%s... %llus"), '\r', Op.c_str(), Current);
+   else
+      snprintf(S, sizeof(S), _("%c%s... %u%%"), '\r', Op.c_str(), (unsigned int)Percent);
    Write(S);
 
    OldOp = Op;
diff --git a/apt-pkg/contrib/progress.h b/apt-pkg/contrib/progress.h
index 4d118ee99..d6a698af3 100644
--- a/apt-pkg/contrib/progress.h
+++ b/apt-pkg/contrib/progress.h
@@ -28,6 +28,7 @@
 class Configuration;
 class APT_PUBLIC OpProgress
 {
+   friend class OpTextProgress;
    unsigned long long Current;
    unsigned long long Total;
    unsigned long long Size;