When the `format_args!` macro is used, formatted args are evaluated
in order to form the argument collection that ends up being formatted
when requested to do so.
For the log macro, this means that any argument that is an expression
was evaluated even if the log level was below current threshold. This
can be examplified by the following code:
```rust
gst::debug!(CAT, "{}", {
println!("fmt arg executed");
"A debug log"
});
```
This used to print "fmt arg executed" even when the log threshold for
`CAT` was filtering `debug` out.
Note that this could break existing code that would incorrectly rely
on the side effect.
For pre-1.20 simply use `%s` as format string instead of escaping the
`%` inline while writing. This allows a simpler implementation and is
also faster, see https://github.com/gtk-rs/gtk-rs-core/pull/583.
It's quite quite common to use similar macros in the form `log::debug!`
or `glib::clone!`. This MR renames the gst log macros so that we can
`gst::debug!` instead of `gst_debug!` and whithout the need for
`use gst::gst_debug`.
And also replace `%` with `%%` for < 1.20 inline, and for >= 1.20 use
the new `gst_debug_log_literal()` function that doesn't require this and
also reduces string allocations further.
It might just be constructed or might be finalized currently and it's
not safe to use any APIs on it.
Instead provide a small wrapper type that allows to get the underlying
pointer and that implements the Display trait to print the name of the
object.
Fixes https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/issues/287
We have to pass `NULL` / `None` instead of the actual default log
function as because of `-Bsymbolic` or how DLLs work on Windows the
external function pointer is different to the internal one.
Make sure that `log_handler` and `DebugMessage::get` do not panic while
processing non-UTF8 characters by using lossy instead of strict UTF8
string conversion.
Tests run parallel in multiple threads. This makes the log_handler test
flaky because it may see log messages triggered by other threads. Make
the handler ignore all messages not in the category we care about.
