See note in https://dev.mysql.com/doc/connector-cpp/1.1/en/connector-cpp-examples-connecting.html
> get_mysql_driver_instance() calls get_driver_instance(), which is not
> thread-safe. Either avoid invoking these methods from within multiple
> threads at once, or surround the calls with a mutex to prevent
> simultaneous execution in multiple threads.
1200: Share libcurl resources across requests r=def- a=heinrich5991
Use the libcurl-share interface to share DNS cache and connections
between different requests.
If compiled with OpenSSL, libcurl can only be safely used from multiple
threads for OpenSSL >= 1.1.0, but this problem is not newly introduced
by this commit: According to libcurl-thread(3):
>OpenSSL <= 1.0.2 the user must set callbacks.
>
>https://www.openssl.org/docs/man1.0.2/crypto/threads.html#DESCRIPTION
>
>https://curl.haxx.se/libcurl/c/opensslthreadlock.html
Co-authored-by: heinrich5991 <heinrich5991@gmail.com>
SHA256 was chosen because it is reasonably standard, the file names
don't explode in length (this rules out SHA512) and it is supported by
basically all versions of OpenSSL (this rules out SHA512/256 and SHA3).
The protocol is changed in a backward compatible way: The supporting
server sends the SHA256 corresponding to the map in the `MAP_DETAILS`
message prior to sending the `MAP_CHANGE` message. The client saves the
SHA256 obtained from the `MAP_DETAILS` message until the next
`MAP_CHANGE` message.
For servers not supporting this protocol, the client falls back to
simply opening maps like in the previous scheme.
Remove the `map_version` tool, it is not being used and would have been
a little bit effort to update.
Use the OpenSSL implementation of SHA256 if it is supported, otherwise
fall back to a public domain one.
Fix#1127.