guix gc: Adjust size suffix based on the amount of data.

* guix/ui.scm (number->size): New procedure.
* guix/scripts/gc.scm (guix-gc)[actions]: Display the amount of
collected-garbage using more specific units.
[ensure-free-space]: Display the size using an appropriate size unit.
* nix/libstore/gc.cc (deletePathRecursive, removeUnusedLinks): Same.
* nix/libstore/optimise-store.cc (showBytes): Move function ...
* nix/libstore/misc.cc: ... to here.  Expand to adjust the output based
on the amount of bytes received.

Change-Id: Idceb1a13f8e45f959d327f53d1a8accb29d2678b

1 files changed, 3 insertions, 4 deletions

diff --git a/nix/libstore/gc.cc b/nix/libstore/gc.cc
index 1766a68412..08638b5115 100644
--- a/nix/libstore/gc.cc
+++ b/nix/libstore/gc.cc
@@ -433,8 +433,7 @@ void LocalStore::deletePathRecursive(GCState & state, const Path & path)
 	printMsg(lvlInfo, format("[%1%%%] deleting '%2%'") % percentage % path);
     } else {
 	auto freed = state.results.bytesFreed + state.bytesInvalidated;
-	freed /=  1024ULL * 1024ULL;
-	printMsg(lvlInfo, format("[%1% MiB] deleting '%2%'") % freed % path);
+	printMsg(lvlInfo, format("[%1%] deleting '%2%'") % showBytes(freed) % path);
     }
 
     state.results.paths.insert(path);
@@ -629,9 +628,9 @@ void LocalStore::removeUnusedLinks(const GCState & state)
     if (stat(linksDir.c_str(), &st) == -1)
         throw SysError(format("statting `%1%'") % linksDir);
     long long overhead = st.st_size;
+    long long freedbytes = (unsharedSize - actualSize - overhead);
 
-    printMsg(lvlInfo, format("note: currently hard linking saves %.2f MiB")
-        % ((unsharedSize - actualSize - overhead) / (1024.0 * 1024.0)));
+    printMsg(lvlInfo, format("note: currently hard linking saves %1%") % showBytes(freedbytes));
 }