AMQP-CPP/src/messageimpl.h

105 lines
2.9 KiB
C++

/**
* Base class for a message implementation
*
* This is the base class for either the returned message or the consumed
* message.
*
* @copyright 2014 Copernica BV
*/
/**
* Namespace
*/
namespace AMQP {
/**
* Class definition
*/
class MessageImpl : public Message
{
protected:
/**
* Constructor
* @param exchange
* @param routingKey
*/
MessageImpl(const std::string &exchange, const std::string &routingKey) :
Message(exchange, routingKey)
{}
public:
/**
* Destructor
*/
virtual ~MessageImpl() {}
/**
* Set the body size
* This field is set when the header is received
* @param uint64_t
*/
void setBodySize(uint64_t size)
{
// safety-check: on 32-bit platforms size_t is obviously also a 32-bit dword
// in which case casting the uint64_t to a size_t could result in truncation
// here we check whether the given size fits inside a size_t
if (std::numeric_limits<size_t>::max() < size) throw std::runtime_error("message is too big for this system");
// store the new size
_bodySize = size;
}
/**
* Append data
* @param buffer incoming data
* @param size size of the data
* @return bool true if the message is now complete
*/
bool append(const char *buffer, uint64_t size)
{
// is this the only data, and also direct complete?
if (_str.empty() && size >= _bodySize)
{
// we have everything
_body = buffer;
// done
return true;
}
else
{
// it does not fit yet, do we have to allocate
if (!_body)
{
// allocate memory in the string
_str.reserve(static_cast<size_t>(_bodySize));
// we now use the data buffer inside the string
_body = _str.data();
}
// safety-check: if the given size exceeds the given message body size
// we truncate it, this should never happen because it indicates a bug
// in the AMQP server implementation, should we report this?
size = std::min(size, _bodySize - _str.size());
// we can not safely append the data to the string, it
// will not exceed the reserved size so it is guaranteed
// not to change the data pointer, we can just leave that
// @todo this is not always necessary; instead, we can refrain from
// allocating this buffer entirely and just insert it into the message
// directly.
_str.append(buffer, static_cast<size_t>(size));
// if the string is filled with the given number of characters we are done now
return _str.size() >= _bodySize;
}
}
};
/**
* End of namespace
*/
}