version: do not store current version as a string

The class I am presenting will make it easier for us to compare it with desired
versions so we can control proper behavior when needed.

Signed-off-by: Glauber Costa <glommer@cloudius-systems.com>

version.hh

@@ -1,14 +1,65 @@
 #pragma once
 
 #include "core/sstring.hh"
+#include "core/print.hh"
 
 namespace version {
+class version {
+    uint8_t maj;
+    uint8_t min;
+    uint16_t rev;
+
+public:
+    version(uint8_t x, uint8_t y = 0, uint16_t z = 0): maj(x), min(y), rev(z) {}
+
+    sstring to_sstring() {
+        return sprint("%d.%d.%d", maj, min, rev);
+    }
+
+    static version current() {
+        static version v(2, 1, 8);
+        return v;
+    }
+
+    bool operator==(version v) const {
+        return (maj == v.maj) && (min == v.min) && (rev == v.rev);
+    }
+
+    bool operator!=(version v) const {
+        return !(v == *this);
+    }
+
+    bool operator<(version v) const {
+        if (maj < v.maj) {
+            return true;
+        } else if (maj > v.maj) {
+            return false;
+        }
+
+        if (min < v.min) {
+            return true;
+        } else if (min > v.min) {
+            return false;
+        }
+        return rev < v.rev;
+    }
+    bool operator<=(version v) {
+        return ((*this < v) || (*this == v));
+    }
+    bool operator>(version v) {
+        return !(*this <= v);
+    }
+    bool operator>=(version v) {
+        return ((*this == v) || !(*this < v));
+    }
+};
+
 inline const int native_protocol() {
     return 3;
 }
 
 inline const sstring& release() {
-    static sstring v = "2.1.8";
-    return v;
+    static thread_local auto str_ver = version::current().to_sstring();
+    return str_ver;
 }
 }