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.
This is a glibc-only extension, so don't bother on other platforms.
Also, according to POSIX, PTHREAD_STACK_MIN is defined in limits.h, so
include climits just to be safe.
Some libraries use thread locals and hence increase the min
requirement.
This is seen on void-linux for example:
> linking a minimal program against cairo gives a
> __static_tls_size of 43008 bytes.
> Doing the same on Ubuntu focal and Debian bullseye,
> __static_tls_size is only 4608.
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.
When a playlist is deleted and drops_references(), any
undo/redo StatefulDiffCommand referncing playlist invoke
Destructible::drop_references() of the Command.
This leads to command_death(). As opposed to UndoTransaction::clear()
the StatefulDiffCommand was not destroyed.
In case of playlists StatefulDiffCommand::_changes contains
PBD::SequenceProperty<std::list<boost::shared_ptr<Region> > >
and shared pointer reference of the playlist regions were kept
indefinitely.
This fixes the following scenario:
New session, import an file, delete the created track,
clean up unused sources (delete unused playlists)[, quit].
A reference to the imported region was kept, because of the
playlist's undo command (insert region). Yet the source file
was deleted.
PS. Most playlist changes are accompanied by GUI zoom/selection
MementoCommands. Those are currently never directly dropped.
command_death() leaves those in place.
