Move the code that attempts to fill missing song metadata out of the
tagreader worker. In the main process, it will be controllable using
settings and calling context.
The methods were moved into a new SongPathParser class that checks new
settings to determine if action should be taken.
Protobuf 3.15 adds a namespace alias for "pb" that conflicts with
Clementine's. Modify Clementine to use "cpb".
Patch provided by @ahesford
Reference: 5c028d6cf4/src/google/protobuf/port.h (L44)
In Application::MoveToNewThread, name the new thread after the object being
moved. Give those objects names as well.
The thread names display in gdb with "info threads".
Previously, the number of processes spawned was always
QThread::idealThreadCount() (returning the number of logical CPU
cores). On new systems with many cores, however, this can result
in 12, 16, 24, or ... processes being spawned, which is a bit
excessive.
This establishes a new config variable,
'max_numprocs_tagclients' within the Settings group, in order
to limit the maximum number of tag client processes that get
spawned. It also adds a means of setting this via the Behavior
page in Settings. It can be set to any integer in the interval
[1, QThread::idealThreadCount()]; it defaults to the maximal value
so as to emulate the old behavior.
* Make TagReaderClient a singleton until it's easier to pass dependencies around
* Add a WaitForSignal() that uses a local event loop to wait for a signal to be emitted
* Add a WaitForFinished() to _MessageReplyBase that blocks using a semaphore
* Add blocking versions of all TagReaderClient methods
* Use the TagReaderClient everywhere that Song::InitFromFile and friends were used before