This uses an atomic counter and spins only on the writer side, which
preserves realtime behavior on the reader side. The spinning yields (by
using the same Boost function from Boost spinlocks) to be
scheduler-friendly.
Fixing this bug also lets us be able to confidently drop garbage early
in the writer if appropriate, so do that and avoid keeping dead wood if
possible.
This reverts commit f95439a502:
"add spinlock to RCU manager to protect concurrent reader() and update() calls"
This is useful in cases where an object owns child objects
which in turn hold a reference to the parent.
In this case PluginInsert has-a Plugin, which may have a reference
to the insert or the Route.
On GLIBC systems pbd_stack_size() adds __pthread_get_minstack,
this is no available on mac systems, causing issues with some
libraries used by plugins.
The distance is between a given offset in the buffer (probably a
read position at some point in time) and the write ptr. Any data after
the write ptr is "old" and not readable, and thus not worth overwriting
since we would not read it anyway.
This is needed primarily for a workaround for #7971. When importing a template
that has been exported on Ardour5 on MacOS we need to fix the paths of the
archive entries.
Later we can use this functionality also to handle imported templates if
templates with the same name already exist.
This commit only adds methods and members to FileArchive, it does not modify
anything to make regressions unlikely. This, however, leads to some duplicated
code. Eventually we should consolidate this a bit.
These changes compile okay for me (using VS2019) although they wouldn't link to my older-built libraries. Hopefully he'll be okay if he builds everything with the same compiler.
gcc, and recent clang-10 can construct new objects
using references as arguments.
However clang-8 (and MSVC?) do not:
"error: no matching function for call to 'operator new'"
The compiler apparently does not expand the template
class A <-> `A*` vs. `A const&`
for different cases.
This is a dumb stack allocator using LIFO allocation/free, with
a fallback to new/delete. This works well for small STL containers
in particular std::vector, but it's also suitable for std::map<>,
in particular copy constructing small POD maps (plugin pin mappings).
Eventually this could be combined with TLSF for a flexible
memory arena management. This is however not currently needed
for any the planned use-cases.
This code is ANSI C++98 compatible, and yet also works with
modern C++11, C++14
~StatefulDiffCommand() may trigger UndoTransaction::command_death()
which may delete the StatefulDiffCommand() that's just being destroyed.
This depends on the signal-connection order, which is undefined.
In any case when a shared_ptr<> object is being destroyed it means
that all references to it are already gone. There's no need to
emit drop_references from the d'tor.
This fixes a case when deleting a plugin, deletes all automation
undo/redo events:
<UndoTransaction name="add automation event">
<MementoCommand type-name="ARDOUR::AutomationList">
...
`delete this;` calls the d'tor which emits drop_references(),
that leads to UndoTransaction::command_death() destroying the
object, whichh causes a double free.
PBD::IgnorableControllable() is no longer used.
It also was problematic, because in every case where a
Controllable is required, min/max range and usually also
get/set value are significant.
