The intention is to make checks for enabled log topics faster.
Every topic has its own structure that is statically defined in the file
where the logs are printed from. The structure is initialized transparently
when it is first used and it contains all the log level flags for the levels
that this topic should print messages. It is then checked on the wp_log()
macro before printing the message.
Topics from SPA/PipeWire are also handled natively, so messages are printed
directly without checking if the topic is enabled, since the PipeWire and SPA
macros do the checking themselves.
Messages coming from GLib are checked inside the handler.
An internal WpLogFields object is used to manage the state of each log
message, populating all the fields appropriately from the place they
are coming from (wp_log, spa_log, glib log), formatting the message and
then printing it. For printing to the journald, we still use the glib
message handler, converting all the needed fields to GLogField on demand.
That message handler does not do any checks for the topic or the level, so
we can just call it to send the message.
The spa_json_encode_string() API does not add a null terminator character. We
need to use the return value to know the size of the encoded string when adding
it to the builder.
Since the string length returned by wp_spa_pod_get_data() does not always match
the size of the actual json object because it is stored in contiguous memory, we
cannot always rely on that API to get the json string data.
The new wp_spa_pod_to_string() always allocates a new string with the same
length as the json size, guaranteeing that the string returned always represents
the json object, regardless of whether it is nested or not. It is always
recommented to use wp_spa_pod_to_string() unless you know what you are doing.
The data pointer of a WpSpaJson object can be bigger than the actual WpSpaJson
size. For example, this happens when iterating an array: instead of
re-allocating the nested data into a new region of memory, the iterator uses
the same region of memory as the parent, and just sets the pointer data and size
to the correct location when creating the nested WpSpaJson object.
This patch makes sure only the data represented by the size is added into the
builder when adding a json object, fixing issues that were happening before when
adding nested objects directly from a second WpSpaJson object.
The string size is always less or equal to the size of the token (len),
so by allocating len+1 bytes we have enough space to write the whole
token and the null byte, if needed.
- pipewire supports parsing unquoted strings and they are used
extensively in JSON .conf files.
- Extend this support into wireplumber, as it wants to use the pipewire
like syntax in its JSON .conf files.
The va_list type might not always be a pointer in some architectures, so we
cannot guarantee it will be modified after using it for a second time in another
function. This fixes the issue by using macros so args does not get copied, and
always gets modified when using it more than once.
