MXS-2263: Process unsigned integer columns correctly

The unsigned integers that would previously be interpreted as negative
values are now correctly converted into their corresponding avro
values. Due to a limitation in the Avro file format, 64-bit unsigned
integers cannot be represented in their unsigned form.

Since both the signed and unsigned versions of a 32-bit integer cannot fit
into a single Avro int, the type for these was changed to long. This is a
backwards incompatible change which means files generated with older
versions will not convert unsigned values correctly.

server/modules/routing/avrorouter/rpl.hh

@@ -202,26 +202,26 @@ public:
     // Called once all columns are processed
     virtual bool commit(const gtid_pos_t& gtid) = 0;
 
-    // 32-bit integer handler
-    virtual void column(int i, int32_t value) = 0;
+    // Integer handler for short types (less than 32 bits)
+    virtual void column_int(int i, int32_t value) = 0;
 
-    // 64-bit integer handler
-    virtual void column(int i, int64_t value) = 0;
+    // Integer handler for long integer types
+    virtual void column_long(int i, int64_t value) = 0;
 
     // Float handler
-    virtual void column(int i, float value) = 0;
+    virtual void column_float(int i, float value) = 0;
 
     // Double handler
-    virtual void column(int i, double value) = 0;
+    virtual void column_double(int i, double value) = 0;
 
     // String handler
-    virtual void column(int i, std::string value) = 0;
+    virtual void column_string(int i, const std::string& value) = 0;
 
     // Bytes handler
-    virtual void column(int i, uint8_t* value, int len) = 0;
+    virtual void column_bytes(int i, uint8_t* value, int len) = 0;
 
     // Empty (NULL) value type handler
-    virtual void column(int i) = 0;
+    virtual void column_null(int i) = 0;
 };
 
 typedef std::auto_ptr<RowEventHandler> SRowEventHandler;