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, 21 insertions, 0 deletions

diff --git a/nix/libstore/misc.cc b/nix/libstore/misc.cc
index bc5dec88bf..e9904f3c4f 100644
--- a/nix/libstore/misc.cc
+++ b/nix/libstore/misc.cc
@@ -1,4 +1,5 @@
 #include "misc.hh"
+#include <math.h>
 #include "store-api.hh"
 #include "local-store.hh"
 #include "globals.hh"
@@ -94,5 +95,25 @@ Paths topoSortPaths(StoreAPI & store, const PathSet & paths)
     return sorted;
 }
 
+/* Max of LLONG_MAX is 8 EiB */
+string showBytes(long long bytes)
+{
+    if (llabs(bytes > exp2l(60))) {
+        return (format("%7.2f EiB") % (bytes / exp2l(60))).str();
+    } else if (llabs(bytes > exp2l(50))) {
+        return (format("%7.2f PiB") % (bytes / exp2l(50))).str();
+    } else if (llabs(bytes > exp2l(40))) {
+        return (format("%7.2f TiB") % (bytes / exp2l(40))).str();
+    } else if (llabs(bytes > exp2l(30))) {
+        return (format("%7.2f GiB") % (bytes / exp2l(30))).str();
+    } else if (llabs(bytes > exp2l(20))) {
+        return (format("%7.2f MiB") % (bytes / exp2l(20))).str();
+    } else if (llabs(bytes > exp2l(10))) {
+        return (format("%7.2f KiB") % (bytes / exp2l(10))).str();
+    } else {
+        return (format("%4f  bytes") % bytes).str();
+    }
+}
+
 
 }