This marks the function safe and returns Result, it also now returns
the ConfiguredAddr since it has to look this up anyway and it makes
testing more easy. Turns out it reduces some duplicate SQL query in
some callers too.
More test code has been moved from dc_imex to test_utils as it's
more genrally applicable.
* refactor(contact): rename and rusty memory allocations
* refactor(contact): use enum to indidcate origin
* refactor(contact): safe blocking and unblocking api
* refactor(contact): only safe and no more cstrings
Add a trait for str.strdup() to replace to_cstring() which avoid the
signature ambiguity with .to_string().
Also instruduce CString::yolo() as a shortcut to
CString::new().unwrap() and use it whenever the variable does can be
deallocated by going out of scope. This is less error prone.
Use some Path.to_c_string() functions where possible.
With this change, kind of message is represented by value of enum
`Viewtype' instead of raw libc::c_int, providing more type safety. This
enum replaces DC_MSG_* constants. The only way to create `Viewtype' from
libc::c_int is smart constructor.
With this change, functions `dc_get_chat_media' and `dc_get_next_media' became
less forgiving about invalid message type arguments. Previously, invalid
message types were implicitly interpreted as 0 (Viewtype::Unknown). Now,
function calls with invalid message type arguments are rejected (error code
returned) on FFI boundary.
Additionally, when `Viewtype' is read from database, it is checked to have
sensible value.
No tests assumed forgiving behaviour.
With this change, passing invalid utf8 string to `dc_send_text_msg' does not
crash application, it prints warning and returns error code.
It should be admitted that this fix is sub-optimal: if input C string is valid
utf8 (which is likely), result of successful conversion to `&str' is discarded
in `dc_send_text_msg', and the same input C string is converted again with
`as_str' in `prepare_msg_raw'.
It is not clear how to fix it in non-disruptive way, since input C string is
passed down to call stack as part of `dc_msg_t' struct, which is part of C ABI.
