The libcamera internal headers are located in src/libcamera/include/.
The directory is added to the compiler headers search path with a meson
include_directories() directive, and internal headers are included with
(e.g. for the internal semaphore.h header)
#include "semaphore.h"
All was well, until libcxx decided to implement the C++20
synchronization library. The __threading_support header gained a
#include <semaphore.h>
to include the pthread's semaphore support. As include_directories()
adds src/libcamera/include/ to the compiler search path with -I, the
internal semaphore.h is included instead of the pthread version.
Needless to say, the compiler isn't happy.
Three options have been considered to fix this issue:
- Use -iquote instead of -I. The -iquote option instructs gcc to only
consider the header search path for headers included with the ""
version. Meson unfortunately doesn't support this option.
- Rename the internal semaphore.h header. This was deemed to be the
beginning of a long whack-a-mole game, where namespace clashes with
system libraries would appear over time (possibly dependent on
particular system configurations) and would need to be constantly
fixed.
- Move the internal headers to another directory to create a unique
namespace through path components. This causes lots of churn in all
the existing source files through the all project.
The first option would be best, but isn't available to us due to missing
support in meson. Even if -iquote support was added, we would need to
fix the problem before a new version of meson containing the required
support would be released.
The third option is thus the only practical solution available. Bite the
bullet, and do it, moving headers to include/libcamera/internal/.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Jacopo Mondi <jacopo@jmondi.org>
Define the thread-safety attributes of the classes and methods that are
either thread-safe or thread-bound. The CameraManager, Camera and
PipelineHandler will be addressed separately.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
The slots list is touched from most of the Signal template functions. In
order to prepare for thread-safety, move handling of the list to a small
number of non-template functions in the SignalBase class.
This incidently fixes a bug in signal disconnection handling where the
signal wasn't removed from the object's signals list, as pointed out by
the signals unit test.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Propagate the return value of the bound method all the way to the caller
of activate(). The value is stored in the arguments pack for indirect
invocation.
As C++ doesn't allow instantiating a variable of type void, we need to
specialize the template class BoundMethodPack for methods returning
void. This in turn requires template specialization for the
BoundMethodArgs class in order to store the return value in the pack,
and for the BoundMemberMethod class to extract the return value from the
pack.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Object instances receive messages dispatched from the event loop of the
thread they belong to. Deleting an object from a different thread is
thus dangerous, unless the caller ensures that no message delivery is in
progress. Document this in the Object class documentation.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Comply with the coding style by removing lots of unneeded semicolons.
Fix a few other coding style violations on the lines touched by those
fixes.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
The BoundMethodBase::activatePack() and the internal
Object::invokeMethod() are duplicate implementation of the same
mechanism. Use the former to replace the latter.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Support all connection types in the BoundMethodBase::activePack()
method. To support this, add a semaphore to the InvokeMessage to signal
delivery.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Add a parent Object to Object instances, and track the parent-children
relationships. Children are bound to the same thread as their parent,
and moving an Object to a thread automatically moves all its children.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Send a synchronous message to objects just before they get moved to a
new thread. This allows the object to perform any required processing.
EventNotifier and Timer objects will use this mechanism to move
themselves to the new thread's event disaptcher.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Add a helper invokeMethod() to the Object class that allows asynchrnous
invocation of any method of an Object instance. Asynchronous invocation
occurs when control returns to the event dispatcher of the target
object's thread, in the context of that thread.
To support this, generalise the SignalMessage implementation to support
automatic deletion of the associated BoundMethod, and rename the message
to InvokeMessage to reflect the more generic purpose.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Move the Slot* classes to bound_method.{h,cpp} and rename them to
Bound*Method*. They will be reused to implement asynchronous method
invocation similar to cross-thread signal delivery.
This is only a move and rename, no functional changes are included.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Allow signals to cross thread boundaries by posting them to the
recipient through messages instead of calling the slot directly when the
recipient lives in a different thread.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Create a new Message class to model a message that can be passed to an
object living in another thread. Only an invalid message type is
currently defined, more messages will be added in the future.
The Thread class is extended with a messages queue, and the Object class
with thread affinity.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Include the header file corresponding to the source file in the very
first position. This complies with the Google C++ coding style
guideliens, and helps ensuring that the headers are self-contained.
Three bugs are already caught by this change (missing includes or
forward declarations) in device_enumerator.h, event_dispatcher_poll.h
and pipeline_handler.h. Fix them.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
When a signal is connected to a member function slot, the slot is not
disconnected when the slot object is deleted. This can lead to calling a
member function of a deleted object if the signal isn't disconnected
manually by the slot object's destructor.
Make signal handling easier by implementing a base Object class that
tracks all connected signals and disconnects from them automatically
when the object is deleted, using template specialization resolution in
the Signal class.
As inheriting from the Object class may to a too harsh requirement for
Signal usage in applications, keep the existing behaviour working if the
slot doesn't inherit from the Object class. We may reconsider this later
and require all slot objects to inherit from the Object class.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
