Implement commit log for storage v2

Reviewers: teon.banek, mferencevic

Reviewed By: teon.banek, mferencevic

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D2148

tests/unit/commit_log_v2.cpp

@@ -0,0 +1,52 @@
+#include "storage/v2/commit_log.hpp"
+
+#include "gtest/gtest.h"
+
+TEST(CommitLog, Simple) {
+  CommitLog log;
+  EXPECT_EQ(log.OldestActive(), 0);
+
+  log.MarkFinished(1);
+  EXPECT_EQ(log.OldestActive(), 0);
+
+  log.MarkFinished(0);
+  EXPECT_EQ(log.OldestActive(), 2);
+}
+
+TEST(CommitLog, Fields) {
+  CommitLog log;
+
+  for (uint64_t i = 0; i < 64; ++i) {
+    log.MarkFinished(i);
+    EXPECT_EQ(log.OldestActive(), i + 1);
+  }
+
+  for (uint64_t i = 128; i < 192; ++i) {
+    log.MarkFinished(i);
+    EXPECT_EQ(log.OldestActive(), 64);
+  }
+
+  for (uint64_t i = 64; i < 128; ++i) {
+    log.MarkFinished(i);
+    EXPECT_EQ(log.OldestActive(), i < 127 ? i + 1 : 192);
+  }
+}
+
+TEST(CommitLog, Blocks) {
+  CommitLog log;
+
+  for (uint64_t i = 0; i < 8192 * 64; ++i) {
+    log.MarkFinished(i);
+    EXPECT_EQ(log.OldestActive(), i + 1);
+  }
+
+  for (uint64_t i = 8192 * 64 * 2; i < 8192 * 64 * 3; ++i) {
+    log.MarkFinished(i);
+    EXPECT_EQ(log.OldestActive(), 8192 * 64);
+  }
+
+  for (uint64_t i = 8192 * 64; i < 8192 * 64; ++i) {
+    log.MarkFinished(i);
+    EXPECT_EQ(log.OldestActive(), i < 8192 * 64 - 1 ? i + 1 : 8192 * 64 * 3);
+  }
+}