RWBackend did not expect that a resultset and an unexpected ERR packet
could be stored in the same buffer. This can happen for example if a
server shuts down immediately after the resultset is sent.
This makes iterating over packets in buffers faster while still
maintaining the requirements for forward iterators. Not using operator+=
makes it clear that this is not a random access iterator.
The largest part of the code deals with the start of a response. Moving
this into a subfunction makes the function clearer as the switch statement
inside a switch statement is removed.
By processing the packets one at a time, the reply state is updated
correctly regardless of how many packets are received. This removes the
need for the clunky code that used modutil_count_signal_packets to detect
the end of the result set.
If a result consists of only OK packets, they would be processed
recursively which most of the time leads to a stack overflow. This can be
prevented by consuming all OK packets in the result in one go.
For lifetime management keep RWBackends in a vector of unique_ptrs.
RWSplitSession keeps the unique_ptrs very private, and provides a vector
of plain pointers for all other interfaces.
This is essentially just a search and replace to change SRWBackend to
RWBackend* and SRWBackendList to PRWBackends, a vector of a raw
pointers. In the next few commits vector<unique_ptr<RWBackend>>
will be used for life time management.
There are a lot of diffs from the global search and replace. Only a few manual
edits had to be done.
list-src -x build | xargs sed -ri 's/SRWBackends/prwbackends/g'
list-src -x build | xargs sed -ri 's/const mxs::SRWBackend\&/const mxs::RWBackend\*/g'
list-src -x build | xargs sed -ri 's/const SRWBackend\&/const RWBackend\*/g'
list-src -x build | xargs sed -ri 's/mxs::SRWBackend\&/mxs::RWBackend\*/g'
list-src -x build | xargs sed -ri 's/mxs::SRWBackend/mxs::RWBackend\*/g'
list-src -x build | xargs sed -ri 's/SRWBackend\(\)/nullptr/g'
list-src -x build | xargs sed -ri 's/mxs::SRWBackend\&/mxs::RWBackend\*/g'
list-src -x build | xargs sed -ri 's/mxs::SRWBackend/mxs::RWBackend\*/g'
list-src -x build | xargs sed -ri 's/SRWBackend\&/RWBackend\*/g'
list-src -x build | xargs sed -ri 's/SRWBackend\b/RWBackend\*/g'
list-src -x build | xargs sed -ri 's/prwbackends/PRWBackends/g'
By splitting the processing and state querying into two separate
functions, the result can be inspected multiple times without triggering
the result processing.
