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path: root/src/libcamera/object.cpp
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2021-05-24libcamera: thread: Document race condition at stop timeLaurent Pinchart
When a thread stops, messages may be left in its message queue. Document this in details, with a way to force processing of pending messages when the thread is stopped. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> Reviewed-by: Umang Jain <umang.jain@ideasonboard.com> Reviewed-by: Hirokazu Honda <hiroh@chromium.org> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
2020-08-24libcamera: object: Fix deleteLater() sample codeUmang Jain
Instead of using "delete obj" in the custom deleter of the shared object, we should have been using the "obj->deleteLater()" to explain how the deleteLater() API should be used in practice. Fixes: 9558886f7a85 ("libcamera: object: Add deleteLater() support) Signed-off-by: Umang Jain <email@uajain.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
2020-07-31libcamera: object: Add deleteLater() supportUmang Jain
This commit adds support to schedule the deletion of an Object to the thread it is bound to (similar to [1]). An Object getting destroyed by a different thread is considered as a violation as per the libcamera threading model. This will be useful for an Object where its ownership is shared via shared pointers in different threads. If the thread which drops the last reference of the Object is a different thread, the destructors get called in that particular thread, not the one Object is bound to. Hence, in order to resolve this kind of situation, the creation of shared pointer can be accompanied by a custom deleter which in turns use deleteLater() to ensure the Object is destroyed in its own thread. [1] https://doc.qt.io/qt-5/qobject.html#deleteLater Signed-off-by: Umang Jain <email@uajain.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
2020-05-16libcamera: Move internal headers to include/libcamera/internal/Laurent Pinchart
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>
2020-02-13libcamera: Document thread-safety attributes of core classesLaurent Pinchart
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>
2020-01-22libcamera: signal: Make slots list privateLaurent Pinchart
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>
2020-01-07libcamera: bound_method: Propagate method return valueLaurent Pinchart
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>
2019-12-09libcamera: object: Document danger of deleting object from other threadLaurent Pinchart
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>
2019-11-08libcamera: Remove unneeded semicolonsLaurent Pinchart
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>
2019-10-29libcamera: object: Add connection type parameter to invokeMethod()Jacopo Mondi
Allow specifying a different connection type than ConnectionTypeQueued for Object::invokeMethod(). Signed-off-by: Jacopo Mondi <jacopo@jmondi.org> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
2019-10-29libcamera: object: Use bound method activePack() for invokeMethod()Laurent Pinchart
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>
2019-10-29libcamera: bound_method: Support connection typesLaurent Pinchart
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>
2019-08-17libcamera: object: Create parent-child relationshipsLaurent Pinchart
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>
2019-08-17libcamera: object: Notify objects of thread moveLaurent Pinchart
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>
2019-08-17libcamera: object: Add an asynchronous method invocation methodLaurent Pinchart
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>
2019-08-17libcamera: signal: Split Slot implementation to reusable classesLaurent Pinchart
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>
2019-07-11libcamera: signal: Support cross-thread signalsLaurent Pinchart
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>
2019-07-11libcamera: thread: Add a messaging passing APILaurent Pinchart
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>
2019-04-19libcamera: Include header related to source file firstLaurent Pinchart
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>
2019-02-13libcamera: signal: Disconnect signal automatically on slot deletionLaurent Pinchart
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>