Previously, "flags" argument of Sql.open was of type libc::c_int, but
only one bit was used: whether to open database read-only. This commit
makes it explicit by changing type to bool and renaming argument.
if the past we had lots of crashes because of unexpected unwrap failures,
mostly related to string.
this commit avoids them eg. for string-conversions that may panic
eg. when encountering a null-byte or by logical programming errors
where an object is assumed to be set but is not under unexpected circumstances.
There is very little API guarantees about this, but clients seem to
expect *something* to work on a closed context. So split this up into
static info an more dynamic context-related info, but let's not
provide any guarantees about what keys are available when.
Fixes#599
A new context is now created by calling Context::new and therefore you
always have a valid context. This is much more in Rust style and will
allow a lot of furture simplifications on the context itself.
The FFI layer has not yet been adjusted in this commit and thus will
fail.
Function `query_row` executes query and calls callback function to process
row returned. Function query_row_col() is special case, that provides
callback function, which returns value of one particular column of row,
ignoring others.
In all cases, that particular column was 0 (first and only column of
query result), since there is no point to select more than one column
with this function -- they are discarded anyway.
This commit removes that redundancy, removing column number argument of
query_row_col() function and adjusting call sites accordingly.
Previously, logging macros (info! warn! error!) accepted integer
argument (data1), that was passed to callback function verbatim. In all
call sites this argument was 0.
With this change, that data1 argument is no longer part of macro
interface, 0 is always passed to callback in internals of these macros.
The function is made safe and now returns Result. Functionally it now
fails when it can not write the newly generated key to the database
whereas before it still returned the key but logged a warning. There
is no reason this shouldn't be able to store the key and silently not
storing the key may result in later operations assuming the key is
available, so failing seems like a better choice.
The function now also uses a proper mutex to guard against multiple
threads generating keys. And this mutex is Context-scoped rather than
fully global (static).
This removes the dc_context_unref function from the Rust API which was
just an alias for dc_close. It still exists on the C API where it
makes sure to free the memory.
It also implements Drop for the context which just calls dc_close to
make sure all the memory is freed. Since you can call dc_close as
many times as you like this ensures that at the Rust level you can't
Drop the struct without releasing the memory.
Finally since memory is now freed by dropping the struct this removes
the #[repr(C)] for the struct. This struct is fully opaque to the C
API.
