From 0ea17216fed3ce949bee298d83d22a35b6b8c476 Mon Sep 17 00:00:00 2001
From: Juliusz Stasiewicz <juliusz.stasiewicz@scylladb.com>
Date: Wed, 29 Jan 2020 16:55:17 +0100
Subject: [PATCH] atomic_cell: special rule for printing counter cells

Until now, attempts to print counter update cell would end up
calling abort() because `atomic_cell_view::value()` has no
specialized visitor for `imr::pod<int64_t>::basic_view<is_mutable>`,
i.e. counter update IMR type. Such visitor is not easy to write
if we want to intercept counters only (and not all int64_t values).

Anyway, linearized byte representation of counter cell would not
be helpful without knowing if it consists of counter shards or
counter update (delta) - and this must be known upon `deserialize`.

This commit introduces simple approach: it determines cell type on
high level (from `atomic_cell_view`) and prints counter contents by
`counter_cell_view` or `atomic_cell_view::counter_update_value()`.

Fixes #5616
---
 atomic_cell.cc | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/atomic_cell.cc b/atomic_cell.cc
index 92adfb1e32..30b0aebf50 100644
--- a/atomic_cell.cc
+++ b/atomic_cell.cc
@@ -21,6 +21,7 @@
 
 #include "atomic_cell.hh"
 #include "atomic_cell_or_collection.hh"
+#include "counters.hh"
 #include "types.hh"
 
 /// LSA mirator for cells with irrelevant type
@@ -218,7 +219,9 @@ std::ostream&
 operator<<(std::ostream& os, const atomic_cell_view& acv) {
     if (acv.is_live()) {
         return fmt_print(os, "atomic_cell{{{},ts={:d},expiry={:d},ttl={:d}}}",
-            to_hex(acv.value().linearize()),
+            acv.is_counter_update()
+                    ? "counter_update_value=" + to_sstring(acv.counter_update_value())
+                    : to_hex(acv.value().linearize()),
             acv.timestamp(),
             acv.is_live_and_has_ttl() ? acv.expiry().time_since_epoch().count() : -1,
             acv.is_live_and_has_ttl() ? acv.ttl().count() : 0);
@@ -238,8 +241,21 @@ operator<<(std::ostream& os, const atomic_cell_view::printer& acvp) {
     auto& type = acvp._type;
     auto& acv = acvp._cell;
     if (acv.is_live()) {
+        std::ostringstream cell_value_string_builder;
+        if (type.is_counter()) {
+            if (acv.is_counter_update()) {
+                cell_value_string_builder << "counter_update_value=" << acv.counter_update_value();
+            } else {
+                cell_value_string_builder << "shards: ";
+                counter_cell_view::with_linearized(acv, [&cell_value_string_builder] (counter_cell_view& ccv) {
+                    cell_value_string_builder << ::join(", ", ccv.shards());
+                });
+            }
+        } else {
+            cell_value_string_builder << type.to_string(acv.value().linearize());
+        }
         return fmt_print(os, "atomic_cell{{{},ts={:d},expiry={:d},ttl={:d}}}",
-            type.to_string(acv.value().linearize()),
+            cell_value_string_builder.str(),
             acv.timestamp(),
             acv.is_live_and_has_ttl() ? acv.expiry().time_since_epoch().count() : -1,
             acv.is_live_and_has_ttl() ? acv.ttl().count() : 0);