| Message ID | 20230530092016.34953-6-tomi.valkeinen@ideasonboard.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series |
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| Related | show |
Hi Tomi, Thank you for the patch. On Tue, May 30, 2023 at 12:20:16PM +0300, Tomi Valkeinen wrote: > We are using pybind11 'smart_holder' branch to solve the Camera > destructor issue (see the comment in this patch, or the commit > that originally added Python bindings support). > > As it would be very nice to use the mainline pybind11 (which is packaged > in distributions), this patch adds a workaround allowing us to move to > the mainline pybind11 version. > > The workaround is simply creating a custom holder class, used only for > the Camera, which wraps around the shared_ptr. This makes the compiler > happy. > > Moving to mainline pybdin11 is achieved with: s/pybdin11/pybind11/ > > - Change the pybind11 wrap to point to the mainline pybdind11 version > > - Change the meson.build file to use a system-installed pybind11 if > available, and use the pybind11 subproject as a fallback. The fallback > is there as a convenience, as pybind11 may not be available in > pre-packaged form in all environments. Given that Python bindings isn't a core feature of libcamera, do we really need a subproject, or could we disable the Python bindings when pybind11 isn't found ? We have subprojects for libyaml and libyuv, as they're required by the libcamera core and the Android camera HAL and not available on AOSP, but for optional features, I would prefer relying on the build environment to provide the necessary dependencies, especially given that both Debian and Fedora have a pybind11 package. > Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> > --- > src/py/libcamera/meson.build | 11 ++-- > src/py/libcamera/py_camera_manager.h | 2 +- > src/py/libcamera/py_color_space.cpp | 2 +- > src/py/libcamera/py_controls_generated.cpp.in | 2 +- > src/py/libcamera/py_enums.cpp | 2 +- > src/py/libcamera/py_formats_generated.cpp.in | 2 +- > src/py/libcamera/py_geometry.cpp | 2 +- > src/py/libcamera/py_helpers.h | 2 +- > src/py/libcamera/py_main.cpp | 52 +++++++++++++++++-- > .../libcamera/py_properties_generated.cpp.in | 2 +- > src/py/libcamera/py_transform.cpp | 2 +- > subprojects/.gitignore | 2 +- > subprojects/pybind11.wrap | 18 ++++--- > 13 files changed, 76 insertions(+), 25 deletions(-) > > diff --git a/src/py/libcamera/meson.build b/src/py/libcamera/meson.build > index f87b1b4d..9d86d8bf 100644 > --- a/src/py/libcamera/meson.build > +++ b/src/py/libcamera/meson.build > @@ -7,10 +7,15 @@ if not py3_dep.found() > subdir_done() > endif > > -pycamera_enabled = true > +pybind11_dep = dependency('pybind11', required : get_option('pycamera'), > + fallback : ['pybind11', 'pybind11_dep']) > + > +if not pybind11_dep.found() > + pycamera_enabled = false > + subdir_done() > +endif > > -pybind11_proj = subproject('pybind11') > -pybind11_dep = pybind11_proj.get_variable('pybind11_dep') > +pycamera_enabled = true > > pycamera_sources = files([ > 'py_camera_manager.cpp', > diff --git a/src/py/libcamera/py_camera_manager.h b/src/py/libcamera/py_camera_manager.h > index 3525057d..3574db23 100644 > --- a/src/py/libcamera/py_camera_manager.h > +++ b/src/py/libcamera/py_camera_manager.h > @@ -9,7 +9,7 @@ > > #include <libcamera/libcamera.h> > > -#include <pybind11/smart_holder.h> > +#include <pybind11/pybind11.h> > > using namespace libcamera; > > diff --git a/src/py/libcamera/py_color_space.cpp b/src/py/libcamera/py_color_space.cpp > index a8301e3d..5201121a 100644 > --- a/src/py/libcamera/py_color_space.cpp > +++ b/src/py/libcamera/py_color_space.cpp > @@ -9,7 +9,7 @@ > #include <libcamera/libcamera.h> > > #include <pybind11/operators.h> > -#include <pybind11/smart_holder.h> > +#include <pybind11/pybind11.h> > #include <pybind11/stl.h> > > namespace py = pybind11; > diff --git a/src/py/libcamera/py_controls_generated.cpp.in b/src/py/libcamera/py_controls_generated.cpp.in > index cb8442ba..18fa57d9 100644 > --- a/src/py/libcamera/py_controls_generated.cpp.in > +++ b/src/py/libcamera/py_controls_generated.cpp.in > @@ -9,7 +9,7 @@ > > #include <libcamera/control_ids.h> > > -#include <pybind11/smart_holder.h> > +#include <pybind11/pybind11.h> > > namespace py = pybind11; > > diff --git a/src/py/libcamera/py_enums.cpp b/src/py/libcamera/py_enums.cpp > index 96d4beef..803c4e7e 100644 > --- a/src/py/libcamera/py_enums.cpp > +++ b/src/py/libcamera/py_enums.cpp > @@ -7,7 +7,7 @@ > > #include <libcamera/libcamera.h> > > -#include <pybind11/smart_holder.h> > +#include <pybind11/pybind11.h> > > namespace py = pybind11; > > diff --git a/src/py/libcamera/py_formats_generated.cpp.in b/src/py/libcamera/py_formats_generated.cpp.in > index b88807f3..a3f7f94d 100644 > --- a/src/py/libcamera/py_formats_generated.cpp.in > +++ b/src/py/libcamera/py_formats_generated.cpp.in > @@ -9,7 +9,7 @@ > > #include <libcamera/formats.h> > > -#include <pybind11/smart_holder.h> > +#include <pybind11/pybind11.h> > > namespace py = pybind11; > > diff --git a/src/py/libcamera/py_geometry.cpp b/src/py/libcamera/py_geometry.cpp > index 84b0cb08..5c2aeac4 100644 > --- a/src/py/libcamera/py_geometry.cpp > +++ b/src/py/libcamera/py_geometry.cpp > @@ -11,7 +11,7 @@ > #include <libcamera/libcamera.h> > > #include <pybind11/operators.h> > -#include <pybind11/smart_holder.h> > +#include <pybind11/pybind11.h> > #include <pybind11/stl.h> > > namespace py = pybind11; > diff --git a/src/py/libcamera/py_helpers.h b/src/py/libcamera/py_helpers.h > index cd31e2cc..983969df 100644 > --- a/src/py/libcamera/py_helpers.h > +++ b/src/py/libcamera/py_helpers.h > @@ -7,7 +7,7 @@ > > #include <libcamera/libcamera.h> > > -#include <pybind11/smart_holder.h> > +#include <pybind11/pybind11.h> > > pybind11::object controlValueToPy(const libcamera::ControlValue &cv); > libcamera::ControlValue pyToControlValue(const pybind11::object &ob, libcamera::ControlType type); > diff --git a/src/py/libcamera/py_main.cpp b/src/py/libcamera/py_main.cpp > index c66b90cd..bbae7a99 100644 > --- a/src/py/libcamera/py_main.cpp > +++ b/src/py/libcamera/py_main.cpp > @@ -17,7 +17,7 @@ > #include <libcamera/libcamera.h> > > #include <pybind11/functional.h> > -#include <pybind11/smart_holder.h> > +#include <pybind11/pybind11.h> > #include <pybind11/stl.h> > #include <pybind11/stl_bind.h> > > @@ -33,6 +33,50 @@ namespace libcamera { > LOG_DEFINE_CATEGORY(Python) > > } Missing blank line. > +/* > + * This is a holder class used only for the Camera class, for the sole purpose > + * of avoiding the compilation issue with Camera's private destructor. > + * > + * pybind11 requires a public destructor for classes held with shared_ptrs, even > + * in cases where the public destructor is not strictly needed. The current > + * understanding is that there are the following options to solve the problem: > + * > + * - Use pybind11 'smart_holder' branch. The downside is that 'smart_holder' > + * is not the mainline branch, and not available in distributions. > + * - https://github.com/pybind/pybind11/pull/2067 > + * - Make the Camera destructor public > + * - Something like the PyCameraSmartPtr here, which adds a layer, hiding the > + * issue. > + */ > +template<typename T> > +class PyCameraSmartPtr > +{ > +public: > + using element_type = T; > + > + PyCameraSmartPtr() > + { > + } > + > + explicit PyCameraSmartPtr(T *) > + { > + throw std::runtime_error("invalid SmartPtr constructor call"); > + } > + > + explicit PyCameraSmartPtr(std::shared_ptr<T> p) > + : ptr_(p) > + { > + } > + > + T *get() const { return ptr_.get(); } > + > + operator std::shared_ptr<T>() const { return ptr_; } > + > +private: > + std::shared_ptr<T> ptr_; > +}; > + > +PYBIND11_DECLARE_HOLDER_TYPE(T, PyCameraSmartPtr<T>); > > /* > * Note: global C++ destructors can be ran on this before the py module is > @@ -65,8 +109,8 @@ PYBIND11_MODULE(_libcamera, m) > * https://pybind11.readthedocs.io/en/latest/advanced/misc.html#avoiding-c-types-in-docstrings > */ > > - auto pyCameraManager = py::class_<PyCameraManager>(m, "CameraManager"); > - auto pyCamera = py::class_<Camera>(m, "Camera"); > + auto pyCameraManager = py::class_<PyCameraManager, std::shared_ptr<PyCameraManager>>(m, "CameraManager"); Why does PyCameraManager need to be changed ? > + auto pyCamera = py::class_<Camera, PyCameraSmartPtr<Camera>>(m, "Camera"); > auto pyCameraConfiguration = py::class_<CameraConfiguration>(m, "CameraConfiguration"); > auto pyCameraConfigurationStatus = py::enum_<CameraConfiguration::Status>(pyCameraConfiguration, "Status"); > auto pyStreamConfiguration = py::class_<StreamConfiguration>(m, "StreamConfiguration"); > @@ -271,7 +315,7 @@ PYBIND11_MODULE(_libcamera, m) > .def("range", &StreamFormats::range); > > pyFrameBufferAllocator > - .def(py::init<std::shared_ptr<Camera>>(), py::keep_alive<1, 2>()) > + .def(py::init<PyCameraSmartPtr<Camera>>(), py::keep_alive<1, 2>()) > .def("allocate", [](FrameBufferAllocator &self, Stream *stream) { > int ret = self.allocate(stream); > if (ret < 0) > diff --git a/src/py/libcamera/py_properties_generated.cpp.in b/src/py/libcamera/py_properties_generated.cpp.in > index 044b2b2a..e49b6e91 100644 > --- a/src/py/libcamera/py_properties_generated.cpp.in > +++ b/src/py/libcamera/py_properties_generated.cpp.in > @@ -9,7 +9,7 @@ > > #include <libcamera/property_ids.h> > > -#include <pybind11/smart_holder.h> > +#include <pybind11/pybind11.h> > > namespace py = pybind11; > > diff --git a/src/py/libcamera/py_transform.cpp b/src/py/libcamera/py_transform.cpp > index 08783e29..f3a0bfaf 100644 > --- a/src/py/libcamera/py_transform.cpp > +++ b/src/py/libcamera/py_transform.cpp > @@ -9,7 +9,7 @@ > #include <libcamera/libcamera.h> > > #include <pybind11/operators.h> > -#include <pybind11/smart_holder.h> > +#include <pybind11/pybind11.h> > #include <pybind11/stl.h> > > namespace py = pybind11; > diff --git a/subprojects/.gitignore b/subprojects/.gitignore > index 0a8fd3a6..ebe59479 100644 > --- a/subprojects/.gitignore > +++ b/subprojects/.gitignore > @@ -4,4 +4,4 @@ > /libyaml > /libyuv > /packagecache > -/pybind11 > +/pybind11-* > diff --git a/subprojects/pybind11.wrap b/subprojects/pybind11.wrap > index dd02687b..96ec57a1 100644 > --- a/subprojects/pybind11.wrap > +++ b/subprojects/pybind11.wrap > @@ -1,11 +1,13 @@ > -# SPDX-License-Identifier: CC0-1.0 > - Please specify a license. > -[wrap-git] > -url = https://github.com/pybind/pybind11.git > -# This is the head of 'smart_holder' branch > -revision = aebdf00cd060b871c5a1e0c2cf4a333503dd0431 > -depth = 1 > -patch_directory = pybind11 > +[wrap-file] > +directory = pybind11-2.10.4 > +source_url = https://github.com/pybind/pybind11/archive/refs/tags/v2.10.4.tar.gz > +source_filename = pybind11-2.10.4.tar.gz > +source_hash = 832e2f309c57da9c1e6d4542dedd34b24e4192ecb4d62f6f4866a737454c9970 > +patch_filename = pybind11_2.10.4-1_patch.zip > +patch_url = https://wrapdb.mesonbuild.com/v2/pybind11_2.10.4-1/get_patch > +patch_hash = 9489d0cdc1244078a3108c52b4591a6f07f3dc30ca7299d3a3c42b84fa763396 > +source_fallback_url = https://github.com/mesonbuild/wrapdb/releases/download/pybind11_2.10.4-1/pybind11-2.10.4.tar.gz > +wrapdb_version = 2.10.4-1 > > [provide] > pybind11 = pybind11_dep
On 30/05/2023 13:12, Laurent Pinchart wrote: > Hi Tomi, > > Thank you for the patch. > > On Tue, May 30, 2023 at 12:20:16PM +0300, Tomi Valkeinen wrote: >> We are using pybind11 'smart_holder' branch to solve the Camera >> destructor issue (see the comment in this patch, or the commit >> that originally added Python bindings support). >> >> As it would be very nice to use the mainline pybind11 (which is packaged >> in distributions), this patch adds a workaround allowing us to move to >> the mainline pybind11 version. >> >> The workaround is simply creating a custom holder class, used only for >> the Camera, which wraps around the shared_ptr. This makes the compiler >> happy. >> >> Moving to mainline pybdin11 is achieved with: > > s/pybdin11/pybind11/ > >> >> - Change the pybind11 wrap to point to the mainline pybdind11 version >> >> - Change the meson.build file to use a system-installed pybind11 if >> available, and use the pybind11 subproject as a fallback. The fallback >> is there as a convenience, as pybind11 may not be available in >> pre-packaged form in all environments. > > Given that Python bindings isn't a core feature of libcamera, do we > really need a subproject, or could we disable the Python bindings when > pybind11 isn't found ? We have subprojects for libyaml and libyuv, as > they're required by the libcamera core and the Android camera HAL and > not available on AOSP, but for optional features, I would prefer relying > on the build environment to provide the necessary dependencies, > especially given that both Debian and Fedora have a pybind11 package. Well... It's for my convenience, at least =). Buildroot doesn't/didn't have a properly working pybind11. Maybe we can drop it, but I'd rather do it later so that we don't mess up too many things at the same time. Or I can just add a patch to my local tree which adds the subproject, if the consensus is to drop it from libcamera. >> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> >> --- >> src/py/libcamera/meson.build | 11 ++-- >> src/py/libcamera/py_camera_manager.h | 2 +- >> src/py/libcamera/py_color_space.cpp | 2 +- >> src/py/libcamera/py_controls_generated.cpp.in | 2 +- >> src/py/libcamera/py_enums.cpp | 2 +- >> src/py/libcamera/py_formats_generated.cpp.in | 2 +- >> src/py/libcamera/py_geometry.cpp | 2 +- >> src/py/libcamera/py_helpers.h | 2 +- >> src/py/libcamera/py_main.cpp | 52 +++++++++++++++++-- >> .../libcamera/py_properties_generated.cpp.in | 2 +- >> src/py/libcamera/py_transform.cpp | 2 +- >> subprojects/.gitignore | 2 +- >> subprojects/pybind11.wrap | 18 ++++--- >> 13 files changed, 76 insertions(+), 25 deletions(-) >> >> diff --git a/src/py/libcamera/meson.build b/src/py/libcamera/meson.build >> index f87b1b4d..9d86d8bf 100644 >> --- a/src/py/libcamera/meson.build >> +++ b/src/py/libcamera/meson.build >> @@ -7,10 +7,15 @@ if not py3_dep.found() >> subdir_done() >> endif >> >> -pycamera_enabled = true >> +pybind11_dep = dependency('pybind11', required : get_option('pycamera'), >> + fallback : ['pybind11', 'pybind11_dep']) >> + >> +if not pybind11_dep.found() >> + pycamera_enabled = false >> + subdir_done() >> +endif >> >> -pybind11_proj = subproject('pybind11') >> -pybind11_dep = pybind11_proj.get_variable('pybind11_dep') >> +pycamera_enabled = true >> >> pycamera_sources = files([ >> 'py_camera_manager.cpp', >> diff --git a/src/py/libcamera/py_camera_manager.h b/src/py/libcamera/py_camera_manager.h >> index 3525057d..3574db23 100644 >> --- a/src/py/libcamera/py_camera_manager.h >> +++ b/src/py/libcamera/py_camera_manager.h >> @@ -9,7 +9,7 @@ >> >> #include <libcamera/libcamera.h> >> >> -#include <pybind11/smart_holder.h> >> +#include <pybind11/pybind11.h> >> >> using namespace libcamera; >> >> diff --git a/src/py/libcamera/py_color_space.cpp b/src/py/libcamera/py_color_space.cpp >> index a8301e3d..5201121a 100644 >> --- a/src/py/libcamera/py_color_space.cpp >> +++ b/src/py/libcamera/py_color_space.cpp >> @@ -9,7 +9,7 @@ >> #include <libcamera/libcamera.h> >> >> #include <pybind11/operators.h> >> -#include <pybind11/smart_holder.h> >> +#include <pybind11/pybind11.h> >> #include <pybind11/stl.h> >> >> namespace py = pybind11; >> diff --git a/src/py/libcamera/py_controls_generated.cpp.in b/src/py/libcamera/py_controls_generated.cpp.in >> index cb8442ba..18fa57d9 100644 >> --- a/src/py/libcamera/py_controls_generated.cpp.in >> +++ b/src/py/libcamera/py_controls_generated.cpp.in >> @@ -9,7 +9,7 @@ >> >> #include <libcamera/control_ids.h> >> >> -#include <pybind11/smart_holder.h> >> +#include <pybind11/pybind11.h> >> >> namespace py = pybind11; >> >> diff --git a/src/py/libcamera/py_enums.cpp b/src/py/libcamera/py_enums.cpp >> index 96d4beef..803c4e7e 100644 >> --- a/src/py/libcamera/py_enums.cpp >> +++ b/src/py/libcamera/py_enums.cpp >> @@ -7,7 +7,7 @@ >> >> #include <libcamera/libcamera.h> >> >> -#include <pybind11/smart_holder.h> >> +#include <pybind11/pybind11.h> >> >> namespace py = pybind11; >> >> diff --git a/src/py/libcamera/py_formats_generated.cpp.in b/src/py/libcamera/py_formats_generated.cpp.in >> index b88807f3..a3f7f94d 100644 >> --- a/src/py/libcamera/py_formats_generated.cpp.in >> +++ b/src/py/libcamera/py_formats_generated.cpp.in >> @@ -9,7 +9,7 @@ >> >> #include <libcamera/formats.h> >> >> -#include <pybind11/smart_holder.h> >> +#include <pybind11/pybind11.h> >> >> namespace py = pybind11; >> >> diff --git a/src/py/libcamera/py_geometry.cpp b/src/py/libcamera/py_geometry.cpp >> index 84b0cb08..5c2aeac4 100644 >> --- a/src/py/libcamera/py_geometry.cpp >> +++ b/src/py/libcamera/py_geometry.cpp >> @@ -11,7 +11,7 @@ >> #include <libcamera/libcamera.h> >> >> #include <pybind11/operators.h> >> -#include <pybind11/smart_holder.h> >> +#include <pybind11/pybind11.h> >> #include <pybind11/stl.h> >> >> namespace py = pybind11; >> diff --git a/src/py/libcamera/py_helpers.h b/src/py/libcamera/py_helpers.h >> index cd31e2cc..983969df 100644 >> --- a/src/py/libcamera/py_helpers.h >> +++ b/src/py/libcamera/py_helpers.h >> @@ -7,7 +7,7 @@ >> >> #include <libcamera/libcamera.h> >> >> -#include <pybind11/smart_holder.h> >> +#include <pybind11/pybind11.h> >> >> pybind11::object controlValueToPy(const libcamera::ControlValue &cv); >> libcamera::ControlValue pyToControlValue(const pybind11::object &ob, libcamera::ControlType type); >> diff --git a/src/py/libcamera/py_main.cpp b/src/py/libcamera/py_main.cpp >> index c66b90cd..bbae7a99 100644 >> --- a/src/py/libcamera/py_main.cpp >> +++ b/src/py/libcamera/py_main.cpp >> @@ -17,7 +17,7 @@ >> #include <libcamera/libcamera.h> >> >> #include <pybind11/functional.h> >> -#include <pybind11/smart_holder.h> >> +#include <pybind11/pybind11.h> >> #include <pybind11/stl.h> >> #include <pybind11/stl_bind.h> >> >> @@ -33,6 +33,50 @@ namespace libcamera { >> LOG_DEFINE_CATEGORY(Python) >> >> } > > Missing blank line. > >> +/* >> + * This is a holder class used only for the Camera class, for the sole purpose >> + * of avoiding the compilation issue with Camera's private destructor. >> + * >> + * pybind11 requires a public destructor for classes held with shared_ptrs, even >> + * in cases where the public destructor is not strictly needed. The current >> + * understanding is that there are the following options to solve the problem: >> + * >> + * - Use pybind11 'smart_holder' branch. The downside is that 'smart_holder' >> + * is not the mainline branch, and not available in distributions. >> + * - https://github.com/pybind/pybind11/pull/2067 >> + * - Make the Camera destructor public >> + * - Something like the PyCameraSmartPtr here, which adds a layer, hiding the >> + * issue. >> + */ >> +template<typename T> >> +class PyCameraSmartPtr >> +{ >> +public: >> + using element_type = T; >> + >> + PyCameraSmartPtr() >> + { >> + } >> + >> + explicit PyCameraSmartPtr(T *) >> + { >> + throw std::runtime_error("invalid SmartPtr constructor call"); >> + } >> + >> + explicit PyCameraSmartPtr(std::shared_ptr<T> p) >> + : ptr_(p) >> + { >> + } >> + >> + T *get() const { return ptr_.get(); } >> + >> + operator std::shared_ptr<T>() const { return ptr_; } >> + >> +private: >> + std::shared_ptr<T> ptr_; >> +}; >> + >> +PYBIND11_DECLARE_HOLDER_TYPE(T, PyCameraSmartPtr<T>); >> >> /* >> * Note: global C++ destructors can be ran on this before the py module is >> @@ -65,8 +109,8 @@ PYBIND11_MODULE(_libcamera, m) >> * https://pybind11.readthedocs.io/en/latest/advanced/misc.html#avoiding-c-types-in-docstrings >> */ >> >> - auto pyCameraManager = py::class_<PyCameraManager>(m, "CameraManager"); >> - auto pyCamera = py::class_<Camera>(m, "Camera"); >> + auto pyCameraManager = py::class_<PyCameraManager, std::shared_ptr<PyCameraManager>>(m, "CameraManager"); > > Why does PyCameraManager need to be changed ? The default holder is unique_ptr. We handle the camera manager with the singleton pattern, using shared_ptr. So we always want to use shared_ptr. If we don't do this, the camera manager gets freed during operation, leading to a crash. I have to say the exact details escape me, but the smart_holder version handles this smartly, as we do return a shared_ptr from the singleton() function. But the mainline version doesn't cope with that, and I believe it converts the shared_ptr to a unique_ptr, unless we specifically tell it to use the shared_ptr as a holder class. I'll add a note about this to the commit message. >> + auto pyCamera = py::class_<Camera, PyCameraSmartPtr<Camera>>(m, "Camera"); >> auto pyCameraConfiguration = py::class_<CameraConfiguration>(m, "CameraConfiguration"); >> auto pyCameraConfigurationStatus = py::enum_<CameraConfiguration::Status>(pyCameraConfiguration, "Status"); >> auto pyStreamConfiguration = py::class_<StreamConfiguration>(m, "StreamConfiguration"); >> @@ -271,7 +315,7 @@ PYBIND11_MODULE(_libcamera, m) >> .def("range", &StreamFormats::range); >> >> pyFrameBufferAllocator >> - .def(py::init<std::shared_ptr<Camera>>(), py::keep_alive<1, 2>()) >> + .def(py::init<PyCameraSmartPtr<Camera>>(), py::keep_alive<1, 2>()) >> .def("allocate", [](FrameBufferAllocator &self, Stream *stream) { >> int ret = self.allocate(stream); >> if (ret < 0) >> diff --git a/src/py/libcamera/py_properties_generated.cpp.in b/src/py/libcamera/py_properties_generated.cpp.in >> index 044b2b2a..e49b6e91 100644 >> --- a/src/py/libcamera/py_properties_generated.cpp.in >> +++ b/src/py/libcamera/py_properties_generated.cpp.in >> @@ -9,7 +9,7 @@ >> >> #include <libcamera/property_ids.h> >> >> -#include <pybind11/smart_holder.h> >> +#include <pybind11/pybind11.h> >> >> namespace py = pybind11; >> >> diff --git a/src/py/libcamera/py_transform.cpp b/src/py/libcamera/py_transform.cpp >> index 08783e29..f3a0bfaf 100644 >> --- a/src/py/libcamera/py_transform.cpp >> +++ b/src/py/libcamera/py_transform.cpp >> @@ -9,7 +9,7 @@ >> #include <libcamera/libcamera.h> >> >> #include <pybind11/operators.h> >> -#include <pybind11/smart_holder.h> >> +#include <pybind11/pybind11.h> >> #include <pybind11/stl.h> >> >> namespace py = pybind11; >> diff --git a/subprojects/.gitignore b/subprojects/.gitignore >> index 0a8fd3a6..ebe59479 100644 >> --- a/subprojects/.gitignore >> +++ b/subprojects/.gitignore >> @@ -4,4 +4,4 @@ >> /libyaml >> /libyuv >> /packagecache >> -/pybind11 >> +/pybind11-* >> diff --git a/subprojects/pybind11.wrap b/subprojects/pybind11.wrap >> index dd02687b..96ec57a1 100644 >> --- a/subprojects/pybind11.wrap >> +++ b/subprojects/pybind11.wrap >> @@ -1,11 +1,13 @@ >> -# SPDX-License-Identifier: CC0-1.0 >> - > > Please specify a license. Hmm, I wonder what it is... This file is downloaded with the "meson wrap install" tool. https://github.com/mesonbuild/wrapdb says "MIT", so perhaps it's that. I hope it won't get overwritten every time we update the wrap with "meson wrap update"... Tomi
Hi Tomi, On Tue, May 30, 2023 at 02:16:23PM +0300, Tomi Valkeinen wrote: > On 30/05/2023 13:12, Laurent Pinchart wrote: > > On Tue, May 30, 2023 at 12:20:16PM +0300, Tomi Valkeinen wrote: > >> We are using pybind11 'smart_holder' branch to solve the Camera > >> destructor issue (see the comment in this patch, or the commit > >> that originally added Python bindings support). > >> > >> As it would be very nice to use the mainline pybind11 (which is packaged > >> in distributions), this patch adds a workaround allowing us to move to > >> the mainline pybind11 version. > >> > >> The workaround is simply creating a custom holder class, used only for > >> the Camera, which wraps around the shared_ptr. This makes the compiler > >> happy. > >> > >> Moving to mainline pybdin11 is achieved with: > > > > s/pybdin11/pybind11/ > > > >> > >> - Change the pybind11 wrap to point to the mainline pybdind11 version > >> > >> - Change the meson.build file to use a system-installed pybind11 if > >> available, and use the pybind11 subproject as a fallback. The fallback > >> is there as a convenience, as pybind11 may not be available in > >> pre-packaged form in all environments. > > > > Given that Python bindings isn't a core feature of libcamera, do we > > really need a subproject, or could we disable the Python bindings when > > pybind11 isn't found ? We have subprojects for libyaml and libyuv, as > > they're required by the libcamera core and the Android camera HAL and > > not available on AOSP, but for optional features, I would prefer relying > > on the build environment to provide the necessary dependencies, > > especially given that both Debian and Fedora have a pybind11 package. > > Well... It's for my convenience, at least =). Buildroot doesn't/didn't > have a properly working pybind11. I think the package is called python-pybind in buildroot. > Maybe we can drop it, but I'd rather do it later so that we don't mess > up too many things at the same time. > > Or I can just add a patch to my local tree which adds the subproject, if > the consensus is to drop it from libcamera. Could you test with the buildroot python-pybind package ? If that works, is there any blocker to dropping the subproject ? I don't mind dropping the subproject in a separate patch, to make it easy to revert it. > >> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> > >> --- > >> src/py/libcamera/meson.build | 11 ++-- > >> src/py/libcamera/py_camera_manager.h | 2 +- > >> src/py/libcamera/py_color_space.cpp | 2 +- > >> src/py/libcamera/py_controls_generated.cpp.in | 2 +- > >> src/py/libcamera/py_enums.cpp | 2 +- > >> src/py/libcamera/py_formats_generated.cpp.in | 2 +- > >> src/py/libcamera/py_geometry.cpp | 2 +- > >> src/py/libcamera/py_helpers.h | 2 +- > >> src/py/libcamera/py_main.cpp | 52 +++++++++++++++++-- > >> .../libcamera/py_properties_generated.cpp.in | 2 +- > >> src/py/libcamera/py_transform.cpp | 2 +- > >> subprojects/.gitignore | 2 +- > >> subprojects/pybind11.wrap | 18 ++++--- > >> 13 files changed, 76 insertions(+), 25 deletions(-) > >> > >> diff --git a/src/py/libcamera/meson.build b/src/py/libcamera/meson.build > >> index f87b1b4d..9d86d8bf 100644 > >> --- a/src/py/libcamera/meson.build > >> +++ b/src/py/libcamera/meson.build > >> @@ -7,10 +7,15 @@ if not py3_dep.found() > >> subdir_done() > >> endif > >> > >> -pycamera_enabled = true > >> +pybind11_dep = dependency('pybind11', required : get_option('pycamera'), > >> + fallback : ['pybind11', 'pybind11_dep']) > >> + > >> +if not pybind11_dep.found() > >> + pycamera_enabled = false > >> + subdir_done() > >> +endif > >> > >> -pybind11_proj = subproject('pybind11') > >> -pybind11_dep = pybind11_proj.get_variable('pybind11_dep') > >> +pycamera_enabled = true > >> > >> pycamera_sources = files([ > >> 'py_camera_manager.cpp', > >> diff --git a/src/py/libcamera/py_camera_manager.h b/src/py/libcamera/py_camera_manager.h > >> index 3525057d..3574db23 100644 > >> --- a/src/py/libcamera/py_camera_manager.h > >> +++ b/src/py/libcamera/py_camera_manager.h > >> @@ -9,7 +9,7 @@ > >> > >> #include <libcamera/libcamera.h> > >> > >> -#include <pybind11/smart_holder.h> > >> +#include <pybind11/pybind11.h> > >> > >> using namespace libcamera; > >> > >> diff --git a/src/py/libcamera/py_color_space.cpp b/src/py/libcamera/py_color_space.cpp > >> index a8301e3d..5201121a 100644 > >> --- a/src/py/libcamera/py_color_space.cpp > >> +++ b/src/py/libcamera/py_color_space.cpp > >> @@ -9,7 +9,7 @@ > >> #include <libcamera/libcamera.h> > >> > >> #include <pybind11/operators.h> > >> -#include <pybind11/smart_holder.h> > >> +#include <pybind11/pybind11.h> > >> #include <pybind11/stl.h> > >> > >> namespace py = pybind11; > >> diff --git a/src/py/libcamera/py_controls_generated.cpp.in b/src/py/libcamera/py_controls_generated.cpp.in > >> index cb8442ba..18fa57d9 100644 > >> --- a/src/py/libcamera/py_controls_generated.cpp.in > >> +++ b/src/py/libcamera/py_controls_generated.cpp.in > >> @@ -9,7 +9,7 @@ > >> > >> #include <libcamera/control_ids.h> > >> > >> -#include <pybind11/smart_holder.h> > >> +#include <pybind11/pybind11.h> > >> > >> namespace py = pybind11; > >> > >> diff --git a/src/py/libcamera/py_enums.cpp b/src/py/libcamera/py_enums.cpp > >> index 96d4beef..803c4e7e 100644 > >> --- a/src/py/libcamera/py_enums.cpp > >> +++ b/src/py/libcamera/py_enums.cpp > >> @@ -7,7 +7,7 @@ > >> > >> #include <libcamera/libcamera.h> > >> > >> -#include <pybind11/smart_holder.h> > >> +#include <pybind11/pybind11.h> > >> > >> namespace py = pybind11; > >> > >> diff --git a/src/py/libcamera/py_formats_generated.cpp.in b/src/py/libcamera/py_formats_generated.cpp.in > >> index b88807f3..a3f7f94d 100644 > >> --- a/src/py/libcamera/py_formats_generated.cpp.in > >> +++ b/src/py/libcamera/py_formats_generated.cpp.in > >> @@ -9,7 +9,7 @@ > >> > >> #include <libcamera/formats.h> > >> > >> -#include <pybind11/smart_holder.h> > >> +#include <pybind11/pybind11.h> > >> > >> namespace py = pybind11; > >> > >> diff --git a/src/py/libcamera/py_geometry.cpp b/src/py/libcamera/py_geometry.cpp > >> index 84b0cb08..5c2aeac4 100644 > >> --- a/src/py/libcamera/py_geometry.cpp > >> +++ b/src/py/libcamera/py_geometry.cpp > >> @@ -11,7 +11,7 @@ > >> #include <libcamera/libcamera.h> > >> > >> #include <pybind11/operators.h> > >> -#include <pybind11/smart_holder.h> > >> +#include <pybind11/pybind11.h> > >> #include <pybind11/stl.h> > >> > >> namespace py = pybind11; > >> diff --git a/src/py/libcamera/py_helpers.h b/src/py/libcamera/py_helpers.h > >> index cd31e2cc..983969df 100644 > >> --- a/src/py/libcamera/py_helpers.h > >> +++ b/src/py/libcamera/py_helpers.h > >> @@ -7,7 +7,7 @@ > >> > >> #include <libcamera/libcamera.h> > >> > >> -#include <pybind11/smart_holder.h> > >> +#include <pybind11/pybind11.h> > >> > >> pybind11::object controlValueToPy(const libcamera::ControlValue &cv); > >> libcamera::ControlValue pyToControlValue(const pybind11::object &ob, libcamera::ControlType type); > >> diff --git a/src/py/libcamera/py_main.cpp b/src/py/libcamera/py_main.cpp > >> index c66b90cd..bbae7a99 100644 > >> --- a/src/py/libcamera/py_main.cpp > >> +++ b/src/py/libcamera/py_main.cpp > >> @@ -17,7 +17,7 @@ > >> #include <libcamera/libcamera.h> > >> > >> #include <pybind11/functional.h> > >> -#include <pybind11/smart_holder.h> > >> +#include <pybind11/pybind11.h> > >> #include <pybind11/stl.h> > >> #include <pybind11/stl_bind.h> > >> > >> @@ -33,6 +33,50 @@ namespace libcamera { > >> LOG_DEFINE_CATEGORY(Python) > >> > >> } > > > > Missing blank line. > > > >> +/* > >> + * This is a holder class used only for the Camera class, for the sole purpose > >> + * of avoiding the compilation issue with Camera's private destructor. > >> + * > >> + * pybind11 requires a public destructor for classes held with shared_ptrs, even > >> + * in cases where the public destructor is not strictly needed. The current > >> + * understanding is that there are the following options to solve the problem: > >> + * > >> + * - Use pybind11 'smart_holder' branch. The downside is that 'smart_holder' > >> + * is not the mainline branch, and not available in distributions. > >> + * - https://github.com/pybind/pybind11/pull/2067 > >> + * - Make the Camera destructor public > >> + * - Something like the PyCameraSmartPtr here, which adds a layer, hiding the > >> + * issue. > >> + */ > >> +template<typename T> > >> +class PyCameraSmartPtr > >> +{ > >> +public: > >> + using element_type = T; > >> + > >> + PyCameraSmartPtr() > >> + { > >> + } > >> + > >> + explicit PyCameraSmartPtr(T *) > >> + { > >> + throw std::runtime_error("invalid SmartPtr constructor call"); > >> + } > >> + > >> + explicit PyCameraSmartPtr(std::shared_ptr<T> p) > >> + : ptr_(p) > >> + { > >> + } > >> + > >> + T *get() const { return ptr_.get(); } > >> + > >> + operator std::shared_ptr<T>() const { return ptr_; } > >> + > >> +private: > >> + std::shared_ptr<T> ptr_; > >> +}; > >> + > >> +PYBIND11_DECLARE_HOLDER_TYPE(T, PyCameraSmartPtr<T>); > >> > >> /* > >> * Note: global C++ destructors can be ran on this before the py module is > >> @@ -65,8 +109,8 @@ PYBIND11_MODULE(_libcamera, m) > >> * https://pybind11.readthedocs.io/en/latest/advanced/misc.html#avoiding-c-types-in-docstrings > >> */ > >> > >> - auto pyCameraManager = py::class_<PyCameraManager>(m, "CameraManager"); > >> - auto pyCamera = py::class_<Camera>(m, "Camera"); > >> + auto pyCameraManager = py::class_<PyCameraManager, std::shared_ptr<PyCameraManager>>(m, "CameraManager"); > > > > Why does PyCameraManager need to be changed ? > > The default holder is unique_ptr. We handle the camera manager with the > singleton pattern, using shared_ptr. So we always want to use shared_ptr. > > If we don't do this, the camera manager gets freed during operation, > leading to a crash. > > I have to say the exact details escape me, but the smart_holder version > handles this smartly, as we do return a shared_ptr from the singleton() > function. That's lots of magic :-) > But the mainline version doesn't cope with that, and I believe > it converts the shared_ptr to a unique_ptr, unless we specifically tell > it to use the shared_ptr as a holder class. > > I'll add a note about this to the commit message. Thanks, that's good enough for me. > >> + auto pyCamera = py::class_<Camera, PyCameraSmartPtr<Camera>>(m, "Camera"); > >> auto pyCameraConfiguration = py::class_<CameraConfiguration>(m, "CameraConfiguration"); > >> auto pyCameraConfigurationStatus = py::enum_<CameraConfiguration::Status>(pyCameraConfiguration, "Status"); > >> auto pyStreamConfiguration = py::class_<StreamConfiguration>(m, "StreamConfiguration"); > >> @@ -271,7 +315,7 @@ PYBIND11_MODULE(_libcamera, m) > >> .def("range", &StreamFormats::range); > >> > >> pyFrameBufferAllocator > >> - .def(py::init<std::shared_ptr<Camera>>(), py::keep_alive<1, 2>()) > >> + .def(py::init<PyCameraSmartPtr<Camera>>(), py::keep_alive<1, 2>()) > >> .def("allocate", [](FrameBufferAllocator &self, Stream *stream) { > >> int ret = self.allocate(stream); > >> if (ret < 0) > >> diff --git a/src/py/libcamera/py_properties_generated.cpp.in b/src/py/libcamera/py_properties_generated.cpp.in > >> index 044b2b2a..e49b6e91 100644 > >> --- a/src/py/libcamera/py_properties_generated.cpp.in > >> +++ b/src/py/libcamera/py_properties_generated.cpp.in > >> @@ -9,7 +9,7 @@ > >> > >> #include <libcamera/property_ids.h> > >> > >> -#include <pybind11/smart_holder.h> > >> +#include <pybind11/pybind11.h> > >> > >> namespace py = pybind11; > >> > >> diff --git a/src/py/libcamera/py_transform.cpp b/src/py/libcamera/py_transform.cpp > >> index 08783e29..f3a0bfaf 100644 > >> --- a/src/py/libcamera/py_transform.cpp > >> +++ b/src/py/libcamera/py_transform.cpp > >> @@ -9,7 +9,7 @@ > >> #include <libcamera/libcamera.h> > >> > >> #include <pybind11/operators.h> > >> -#include <pybind11/smart_holder.h> > >> +#include <pybind11/pybind11.h> > >> #include <pybind11/stl.h> > >> > >> namespace py = pybind11; > >> diff --git a/subprojects/.gitignore b/subprojects/.gitignore > >> index 0a8fd3a6..ebe59479 100644 > >> --- a/subprojects/.gitignore > >> +++ b/subprojects/.gitignore > >> @@ -4,4 +4,4 @@ > >> /libyaml > >> /libyuv > >> /packagecache > >> -/pybind11 > >> +/pybind11-* > >> diff --git a/subprojects/pybind11.wrap b/subprojects/pybind11.wrap > >> index dd02687b..96ec57a1 100644 > >> --- a/subprojects/pybind11.wrap > >> +++ b/subprojects/pybind11.wrap > >> @@ -1,11 +1,13 @@ > >> -# SPDX-License-Identifier: CC0-1.0 > >> - > > > > Please specify a license. > > Hmm, I wonder what it is... This file is downloaded with the "meson wrap > install" tool. https://github.com/mesonbuild/wrapdb says "MIT", so > perhaps it's that. I hope it won't get overwritten every time we update > the wrap with "meson wrap update"... If we drop the subproject that won't be a problem anymore ;-)
On 30/05/2023 14:29, Laurent Pinchart wrote: > Hi Tomi, > > On Tue, May 30, 2023 at 02:16:23PM +0300, Tomi Valkeinen wrote: >> On 30/05/2023 13:12, Laurent Pinchart wrote: >>> On Tue, May 30, 2023 at 12:20:16PM +0300, Tomi Valkeinen wrote: >>>> We are using pybind11 'smart_holder' branch to solve the Camera >>>> destructor issue (see the comment in this patch, or the commit >>>> that originally added Python bindings support). >>>> >>>> As it would be very nice to use the mainline pybind11 (which is packaged >>>> in distributions), this patch adds a workaround allowing us to move to >>>> the mainline pybind11 version. >>>> >>>> The workaround is simply creating a custom holder class, used only for >>>> the Camera, which wraps around the shared_ptr. This makes the compiler >>>> happy. >>>> >>>> Moving to mainline pybdin11 is achieved with: >>> >>> s/pybdin11/pybind11/ >>> >>>> >>>> - Change the pybind11 wrap to point to the mainline pybdind11 version >>>> >>>> - Change the meson.build file to use a system-installed pybind11 if >>>> available, and use the pybind11 subproject as a fallback. The fallback >>>> is there as a convenience, as pybind11 may not be available in >>>> pre-packaged form in all environments. >>> >>> Given that Python bindings isn't a core feature of libcamera, do we >>> really need a subproject, or could we disable the Python bindings when >>> pybind11 isn't found ? We have subprojects for libyaml and libyuv, as >>> they're required by the libcamera core and the Android camera HAL and >>> not available on AOSP, but for optional features, I would prefer relying >>> on the build environment to provide the necessary dependencies, >>> especially given that both Debian and Fedora have a pybind11 package. >> >> Well... It's for my convenience, at least =). Buildroot doesn't/didn't >> have a properly working pybind11. > > I think the package is called python-pybind in buildroot. > >> Maybe we can drop it, but I'd rather do it later so that we don't mess >> up too many things at the same time. >> >> Or I can just add a patch to my local tree which adds the subproject, if >> the consensus is to drop it from libcamera. > > Could you test with the buildroot python-pybind package ? If that works, > is there any blocker to dropping the subproject ? I will try with the latest buildroot. The python-pybind didn't work when I tried it the some time ago. The issues were the familiar "what belongs to the host and what belongs to the target and how does the host get the python details about the target". > I don't mind dropping the subproject in a separate patch, to make it > easy to revert it. > >>>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> >>>> --- >>>> src/py/libcamera/meson.build | 11 ++-- >>>> src/py/libcamera/py_camera_manager.h | 2 +- >>>> src/py/libcamera/py_color_space.cpp | 2 +- >>>> src/py/libcamera/py_controls_generated.cpp.in | 2 +- >>>> src/py/libcamera/py_enums.cpp | 2 +- >>>> src/py/libcamera/py_formats_generated.cpp.in | 2 +- >>>> src/py/libcamera/py_geometry.cpp | 2 +- >>>> src/py/libcamera/py_helpers.h | 2 +- >>>> src/py/libcamera/py_main.cpp | 52 +++++++++++++++++-- >>>> .../libcamera/py_properties_generated.cpp.in | 2 +- >>>> src/py/libcamera/py_transform.cpp | 2 +- >>>> subprojects/.gitignore | 2 +- >>>> subprojects/pybind11.wrap | 18 ++++--- >>>> 13 files changed, 76 insertions(+), 25 deletions(-) >>>> >>>> diff --git a/src/py/libcamera/meson.build b/src/py/libcamera/meson.build >>>> index f87b1b4d..9d86d8bf 100644 >>>> --- a/src/py/libcamera/meson.build >>>> +++ b/src/py/libcamera/meson.build >>>> @@ -7,10 +7,15 @@ if not py3_dep.found() >>>> subdir_done() >>>> endif >>>> >>>> -pycamera_enabled = true >>>> +pybind11_dep = dependency('pybind11', required : get_option('pycamera'), >>>> + fallback : ['pybind11', 'pybind11_dep']) >>>> + >>>> +if not pybind11_dep.found() >>>> + pycamera_enabled = false >>>> + subdir_done() >>>> +endif >>>> >>>> -pybind11_proj = subproject('pybind11') >>>> -pybind11_dep = pybind11_proj.get_variable('pybind11_dep') >>>> +pycamera_enabled = true >>>> >>>> pycamera_sources = files([ >>>> 'py_camera_manager.cpp', >>>> diff --git a/src/py/libcamera/py_camera_manager.h b/src/py/libcamera/py_camera_manager.h >>>> index 3525057d..3574db23 100644 >>>> --- a/src/py/libcamera/py_camera_manager.h >>>> +++ b/src/py/libcamera/py_camera_manager.h >>>> @@ -9,7 +9,7 @@ >>>> >>>> #include <libcamera/libcamera.h> >>>> >>>> -#include <pybind11/smart_holder.h> >>>> +#include <pybind11/pybind11.h> >>>> >>>> using namespace libcamera; >>>> >>>> diff --git a/src/py/libcamera/py_color_space.cpp b/src/py/libcamera/py_color_space.cpp >>>> index a8301e3d..5201121a 100644 >>>> --- a/src/py/libcamera/py_color_space.cpp >>>> +++ b/src/py/libcamera/py_color_space.cpp >>>> @@ -9,7 +9,7 @@ >>>> #include <libcamera/libcamera.h> >>>> >>>> #include <pybind11/operators.h> >>>> -#include <pybind11/smart_holder.h> >>>> +#include <pybind11/pybind11.h> >>>> #include <pybind11/stl.h> >>>> >>>> namespace py = pybind11; >>>> diff --git a/src/py/libcamera/py_controls_generated.cpp.in b/src/py/libcamera/py_controls_generated.cpp.in >>>> index cb8442ba..18fa57d9 100644 >>>> --- a/src/py/libcamera/py_controls_generated.cpp.in >>>> +++ b/src/py/libcamera/py_controls_generated.cpp.in >>>> @@ -9,7 +9,7 @@ >>>> >>>> #include <libcamera/control_ids.h> >>>> >>>> -#include <pybind11/smart_holder.h> >>>> +#include <pybind11/pybind11.h> >>>> >>>> namespace py = pybind11; >>>> >>>> diff --git a/src/py/libcamera/py_enums.cpp b/src/py/libcamera/py_enums.cpp >>>> index 96d4beef..803c4e7e 100644 >>>> --- a/src/py/libcamera/py_enums.cpp >>>> +++ b/src/py/libcamera/py_enums.cpp >>>> @@ -7,7 +7,7 @@ >>>> >>>> #include <libcamera/libcamera.h> >>>> >>>> -#include <pybind11/smart_holder.h> >>>> +#include <pybind11/pybind11.h> >>>> >>>> namespace py = pybind11; >>>> >>>> diff --git a/src/py/libcamera/py_formats_generated.cpp.in b/src/py/libcamera/py_formats_generated.cpp.in >>>> index b88807f3..a3f7f94d 100644 >>>> --- a/src/py/libcamera/py_formats_generated.cpp.in >>>> +++ b/src/py/libcamera/py_formats_generated.cpp.in >>>> @@ -9,7 +9,7 @@ >>>> >>>> #include <libcamera/formats.h> >>>> >>>> -#include <pybind11/smart_holder.h> >>>> +#include <pybind11/pybind11.h> >>>> >>>> namespace py = pybind11; >>>> >>>> diff --git a/src/py/libcamera/py_geometry.cpp b/src/py/libcamera/py_geometry.cpp >>>> index 84b0cb08..5c2aeac4 100644 >>>> --- a/src/py/libcamera/py_geometry.cpp >>>> +++ b/src/py/libcamera/py_geometry.cpp >>>> @@ -11,7 +11,7 @@ >>>> #include <libcamera/libcamera.h> >>>> >>>> #include <pybind11/operators.h> >>>> -#include <pybind11/smart_holder.h> >>>> +#include <pybind11/pybind11.h> >>>> #include <pybind11/stl.h> >>>> >>>> namespace py = pybind11; >>>> diff --git a/src/py/libcamera/py_helpers.h b/src/py/libcamera/py_helpers.h >>>> index cd31e2cc..983969df 100644 >>>> --- a/src/py/libcamera/py_helpers.h >>>> +++ b/src/py/libcamera/py_helpers.h >>>> @@ -7,7 +7,7 @@ >>>> >>>> #include <libcamera/libcamera.h> >>>> >>>> -#include <pybind11/smart_holder.h> >>>> +#include <pybind11/pybind11.h> >>>> >>>> pybind11::object controlValueToPy(const libcamera::ControlValue &cv); >>>> libcamera::ControlValue pyToControlValue(const pybind11::object &ob, libcamera::ControlType type); >>>> diff --git a/src/py/libcamera/py_main.cpp b/src/py/libcamera/py_main.cpp >>>> index c66b90cd..bbae7a99 100644 >>>> --- a/src/py/libcamera/py_main.cpp >>>> +++ b/src/py/libcamera/py_main.cpp >>>> @@ -17,7 +17,7 @@ >>>> #include <libcamera/libcamera.h> >>>> >>>> #include <pybind11/functional.h> >>>> -#include <pybind11/smart_holder.h> >>>> +#include <pybind11/pybind11.h> >>>> #include <pybind11/stl.h> >>>> #include <pybind11/stl_bind.h> >>>> >>>> @@ -33,6 +33,50 @@ namespace libcamera { >>>> LOG_DEFINE_CATEGORY(Python) >>>> >>>> } >>> >>> Missing blank line. >>> >>>> +/* >>>> + * This is a holder class used only for the Camera class, for the sole purpose >>>> + * of avoiding the compilation issue with Camera's private destructor. >>>> + * >>>> + * pybind11 requires a public destructor for classes held with shared_ptrs, even >>>> + * in cases where the public destructor is not strictly needed. The current >>>> + * understanding is that there are the following options to solve the problem: >>>> + * >>>> + * - Use pybind11 'smart_holder' branch. The downside is that 'smart_holder' >>>> + * is not the mainline branch, and not available in distributions. >>>> + * - https://github.com/pybind/pybind11/pull/2067 >>>> + * - Make the Camera destructor public >>>> + * - Something like the PyCameraSmartPtr here, which adds a layer, hiding the >>>> + * issue. >>>> + */ >>>> +template<typename T> >>>> +class PyCameraSmartPtr >>>> +{ >>>> +public: >>>> + using element_type = T; >>>> + >>>> + PyCameraSmartPtr() >>>> + { >>>> + } >>>> + >>>> + explicit PyCameraSmartPtr(T *) >>>> + { >>>> + throw std::runtime_error("invalid SmartPtr constructor call"); >>>> + } >>>> + >>>> + explicit PyCameraSmartPtr(std::shared_ptr<T> p) >>>> + : ptr_(p) >>>> + { >>>> + } >>>> + >>>> + T *get() const { return ptr_.get(); } >>>> + >>>> + operator std::shared_ptr<T>() const { return ptr_; } >>>> + >>>> +private: >>>> + std::shared_ptr<T> ptr_; >>>> +}; >>>> + >>>> +PYBIND11_DECLARE_HOLDER_TYPE(T, PyCameraSmartPtr<T>); >>>> >>>> /* >>>> * Note: global C++ destructors can be ran on this before the py module is >>>> @@ -65,8 +109,8 @@ PYBIND11_MODULE(_libcamera, m) >>>> * https://pybind11.readthedocs.io/en/latest/advanced/misc.html#avoiding-c-types-in-docstrings >>>> */ >>>> >>>> - auto pyCameraManager = py::class_<PyCameraManager>(m, "CameraManager"); >>>> - auto pyCamera = py::class_<Camera>(m, "Camera"); >>>> + auto pyCameraManager = py::class_<PyCameraManager, std::shared_ptr<PyCameraManager>>(m, "CameraManager"); >>> >>> Why does PyCameraManager need to be changed ? >> >> The default holder is unique_ptr. We handle the camera manager with the >> singleton pattern, using shared_ptr. So we always want to use shared_ptr. >> >> If we don't do this, the camera manager gets freed during operation, >> leading to a crash. >> >> I have to say the exact details escape me, but the smart_holder version >> handles this smartly, as we do return a shared_ptr from the singleton() >> function. > > That's lots of magic :-) Indeed. I think the main thing/feature with pybind11 is the handling of the memory between Python and C++. It's complex... Tomi
On 30/05/2023 14:29, Laurent Pinchart wrote: > Hi Tomi, > > On Tue, May 30, 2023 at 02:16:23PM +0300, Tomi Valkeinen wrote: >> On 30/05/2023 13:12, Laurent Pinchart wrote: >>> On Tue, May 30, 2023 at 12:20:16PM +0300, Tomi Valkeinen wrote: >>>> We are using pybind11 'smart_holder' branch to solve the Camera >>>> destructor issue (see the comment in this patch, or the commit >>>> that originally added Python bindings support). >>>> >>>> As it would be very nice to use the mainline pybind11 (which is packaged >>>> in distributions), this patch adds a workaround allowing us to move to >>>> the mainline pybind11 version. >>>> >>>> The workaround is simply creating a custom holder class, used only for >>>> the Camera, which wraps around the shared_ptr. This makes the compiler >>>> happy. >>>> >>>> Moving to mainline pybdin11 is achieved with: >>> >>> s/pybdin11/pybind11/ >>> >>>> >>>> - Change the pybind11 wrap to point to the mainline pybdind11 version >>>> >>>> - Change the meson.build file to use a system-installed pybind11 if >>>> available, and use the pybind11 subproject as a fallback. The fallback >>>> is there as a convenience, as pybind11 may not be available in >>>> pre-packaged form in all environments. >>> >>> Given that Python bindings isn't a core feature of libcamera, do we >>> really need a subproject, or could we disable the Python bindings when >>> pybind11 isn't found ? We have subprojects for libyaml and libyuv, as >>> they're required by the libcamera core and the Android camera HAL and >>> not available on AOSP, but for optional features, I would prefer relying >>> on the build environment to provide the necessary dependencies, >>> especially given that both Debian and Fedora have a pybind11 package. >> >> Well... It's for my convenience, at least =). Buildroot doesn't/didn't >> have a properly working pybind11. > > I think the package is called python-pybind in buildroot. > >> Maybe we can drop it, but I'd rather do it later so that we don't mess >> up too many things at the same time. >> >> Or I can just add a patch to my local tree which adds the subproject, if >> the consensus is to drop it from libcamera. > > Could you test with the buildroot python-pybind package ? If that works, > is there any blocker to dropping the subproject ? Buildroot seemed to work fine for me with a quick test, so let's drop the subproject. If this turns out to be a problem, it's easy to add it back. Tomi
diff --git a/src/py/libcamera/meson.build b/src/py/libcamera/meson.build index f87b1b4d..9d86d8bf 100644 --- a/src/py/libcamera/meson.build +++ b/src/py/libcamera/meson.build @@ -7,10 +7,15 @@ if not py3_dep.found() subdir_done() endif -pycamera_enabled = true +pybind11_dep = dependency('pybind11', required : get_option('pycamera'), + fallback : ['pybind11', 'pybind11_dep']) + +if not pybind11_dep.found() + pycamera_enabled = false + subdir_done() +endif -pybind11_proj = subproject('pybind11') -pybind11_dep = pybind11_proj.get_variable('pybind11_dep') +pycamera_enabled = true pycamera_sources = files([ 'py_camera_manager.cpp', diff --git a/src/py/libcamera/py_camera_manager.h b/src/py/libcamera/py_camera_manager.h index 3525057d..3574db23 100644 --- a/src/py/libcamera/py_camera_manager.h +++ b/src/py/libcamera/py_camera_manager.h @@ -9,7 +9,7 @@ #include <libcamera/libcamera.h> -#include <pybind11/smart_holder.h> +#include <pybind11/pybind11.h> using namespace libcamera; diff --git a/src/py/libcamera/py_color_space.cpp b/src/py/libcamera/py_color_space.cpp index a8301e3d..5201121a 100644 --- a/src/py/libcamera/py_color_space.cpp +++ b/src/py/libcamera/py_color_space.cpp @@ -9,7 +9,7 @@ #include <libcamera/libcamera.h> #include <pybind11/operators.h> -#include <pybind11/smart_holder.h> +#include <pybind11/pybind11.h> #include <pybind11/stl.h> namespace py = pybind11; diff --git a/src/py/libcamera/py_controls_generated.cpp.in b/src/py/libcamera/py_controls_generated.cpp.in index cb8442ba..18fa57d9 100644 --- a/src/py/libcamera/py_controls_generated.cpp.in +++ b/src/py/libcamera/py_controls_generated.cpp.in @@ -9,7 +9,7 @@ #include <libcamera/control_ids.h> -#include <pybind11/smart_holder.h> +#include <pybind11/pybind11.h> namespace py = pybind11; diff --git a/src/py/libcamera/py_enums.cpp b/src/py/libcamera/py_enums.cpp index 96d4beef..803c4e7e 100644 --- a/src/py/libcamera/py_enums.cpp +++ b/src/py/libcamera/py_enums.cpp @@ -7,7 +7,7 @@ #include <libcamera/libcamera.h> -#include <pybind11/smart_holder.h> +#include <pybind11/pybind11.h> namespace py = pybind11; diff --git a/src/py/libcamera/py_formats_generated.cpp.in b/src/py/libcamera/py_formats_generated.cpp.in index b88807f3..a3f7f94d 100644 --- a/src/py/libcamera/py_formats_generated.cpp.in +++ b/src/py/libcamera/py_formats_generated.cpp.in @@ -9,7 +9,7 @@ #include <libcamera/formats.h> -#include <pybind11/smart_holder.h> +#include <pybind11/pybind11.h> namespace py = pybind11; diff --git a/src/py/libcamera/py_geometry.cpp b/src/py/libcamera/py_geometry.cpp index 84b0cb08..5c2aeac4 100644 --- a/src/py/libcamera/py_geometry.cpp +++ b/src/py/libcamera/py_geometry.cpp @@ -11,7 +11,7 @@ #include <libcamera/libcamera.h> #include <pybind11/operators.h> -#include <pybind11/smart_holder.h> +#include <pybind11/pybind11.h> #include <pybind11/stl.h> namespace py = pybind11; diff --git a/src/py/libcamera/py_helpers.h b/src/py/libcamera/py_helpers.h index cd31e2cc..983969df 100644 --- a/src/py/libcamera/py_helpers.h +++ b/src/py/libcamera/py_helpers.h @@ -7,7 +7,7 @@ #include <libcamera/libcamera.h> -#include <pybind11/smart_holder.h> +#include <pybind11/pybind11.h> pybind11::object controlValueToPy(const libcamera::ControlValue &cv); libcamera::ControlValue pyToControlValue(const pybind11::object &ob, libcamera::ControlType type); diff --git a/src/py/libcamera/py_main.cpp b/src/py/libcamera/py_main.cpp index c66b90cd..bbae7a99 100644 --- a/src/py/libcamera/py_main.cpp +++ b/src/py/libcamera/py_main.cpp @@ -17,7 +17,7 @@ #include <libcamera/libcamera.h> #include <pybind11/functional.h> -#include <pybind11/smart_holder.h> +#include <pybind11/pybind11.h> #include <pybind11/stl.h> #include <pybind11/stl_bind.h> @@ -33,6 +33,50 @@ namespace libcamera { LOG_DEFINE_CATEGORY(Python) } +/* + * This is a holder class used only for the Camera class, for the sole purpose + * of avoiding the compilation issue with Camera's private destructor. + * + * pybind11 requires a public destructor for classes held with shared_ptrs, even + * in cases where the public destructor is not strictly needed. The current + * understanding is that there are the following options to solve the problem: + * + * - Use pybind11 'smart_holder' branch. The downside is that 'smart_holder' + * is not the mainline branch, and not available in distributions. + * - https://github.com/pybind/pybind11/pull/2067 + * - Make the Camera destructor public + * - Something like the PyCameraSmartPtr here, which adds a layer, hiding the + * issue. + */ +template<typename T> +class PyCameraSmartPtr +{ +public: + using element_type = T; + + PyCameraSmartPtr() + { + } + + explicit PyCameraSmartPtr(T *) + { + throw std::runtime_error("invalid SmartPtr constructor call"); + } + + explicit PyCameraSmartPtr(std::shared_ptr<T> p) + : ptr_(p) + { + } + + T *get() const { return ptr_.get(); } + + operator std::shared_ptr<T>() const { return ptr_; } + +private: + std::shared_ptr<T> ptr_; +}; + +PYBIND11_DECLARE_HOLDER_TYPE(T, PyCameraSmartPtr<T>); /* * Note: global C++ destructors can be ran on this before the py module is @@ -65,8 +109,8 @@ PYBIND11_MODULE(_libcamera, m) * https://pybind11.readthedocs.io/en/latest/advanced/misc.html#avoiding-c-types-in-docstrings */ - auto pyCameraManager = py::class_<PyCameraManager>(m, "CameraManager"); - auto pyCamera = py::class_<Camera>(m, "Camera"); + auto pyCameraManager = py::class_<PyCameraManager, std::shared_ptr<PyCameraManager>>(m, "CameraManager"); + auto pyCamera = py::class_<Camera, PyCameraSmartPtr<Camera>>(m, "Camera"); auto pyCameraConfiguration = py::class_<CameraConfiguration>(m, "CameraConfiguration"); auto pyCameraConfigurationStatus = py::enum_<CameraConfiguration::Status>(pyCameraConfiguration, "Status"); auto pyStreamConfiguration = py::class_<StreamConfiguration>(m, "StreamConfiguration"); @@ -271,7 +315,7 @@ PYBIND11_MODULE(_libcamera, m) .def("range", &StreamFormats::range); pyFrameBufferAllocator - .def(py::init<std::shared_ptr<Camera>>(), py::keep_alive<1, 2>()) + .def(py::init<PyCameraSmartPtr<Camera>>(), py::keep_alive<1, 2>()) .def("allocate", [](FrameBufferAllocator &self, Stream *stream) { int ret = self.allocate(stream); if (ret < 0) diff --git a/src/py/libcamera/py_properties_generated.cpp.in b/src/py/libcamera/py_properties_generated.cpp.in index 044b2b2a..e49b6e91 100644 --- a/src/py/libcamera/py_properties_generated.cpp.in +++ b/src/py/libcamera/py_properties_generated.cpp.in @@ -9,7 +9,7 @@ #include <libcamera/property_ids.h> -#include <pybind11/smart_holder.h> +#include <pybind11/pybind11.h> namespace py = pybind11; diff --git a/src/py/libcamera/py_transform.cpp b/src/py/libcamera/py_transform.cpp index 08783e29..f3a0bfaf 100644 --- a/src/py/libcamera/py_transform.cpp +++ b/src/py/libcamera/py_transform.cpp @@ -9,7 +9,7 @@ #include <libcamera/libcamera.h> #include <pybind11/operators.h> -#include <pybind11/smart_holder.h> +#include <pybind11/pybind11.h> #include <pybind11/stl.h> namespace py = pybind11; diff --git a/subprojects/.gitignore b/subprojects/.gitignore index 0a8fd3a6..ebe59479 100644 --- a/subprojects/.gitignore +++ b/subprojects/.gitignore @@ -4,4 +4,4 @@ /libyaml /libyuv /packagecache -/pybind11 +/pybind11-* diff --git a/subprojects/pybind11.wrap b/subprojects/pybind11.wrap index dd02687b..96ec57a1 100644 --- a/subprojects/pybind11.wrap +++ b/subprojects/pybind11.wrap @@ -1,11 +1,13 @@ -# SPDX-License-Identifier: CC0-1.0 - -[wrap-git] -url = https://github.com/pybind/pybind11.git -# This is the head of 'smart_holder' branch -revision = aebdf00cd060b871c5a1e0c2cf4a333503dd0431 -depth = 1 -patch_directory = pybind11 +[wrap-file] +directory = pybind11-2.10.4 +source_url = https://github.com/pybind/pybind11/archive/refs/tags/v2.10.4.tar.gz +source_filename = pybind11-2.10.4.tar.gz +source_hash = 832e2f309c57da9c1e6d4542dedd34b24e4192ecb4d62f6f4866a737454c9970 +patch_filename = pybind11_2.10.4-1_patch.zip +patch_url = https://wrapdb.mesonbuild.com/v2/pybind11_2.10.4-1/get_patch +patch_hash = 9489d0cdc1244078a3108c52b4591a6f07f3dc30ca7299d3a3c42b84fa763396 +source_fallback_url = https://github.com/mesonbuild/wrapdb/releases/download/pybind11_2.10.4-1/pybind11-2.10.4.tar.gz +wrapdb_version = 2.10.4-1 [provide] pybind11 = pybind11_dep
We are using pybind11 'smart_holder' branch to solve the Camera destructor issue (see the comment in this patch, or the commit that originally added Python bindings support). As it would be very nice to use the mainline pybind11 (which is packaged in distributions), this patch adds a workaround allowing us to move to the mainline pybind11 version. The workaround is simply creating a custom holder class, used only for the Camera, which wraps around the shared_ptr. This makes the compiler happy. Moving to mainline pybdin11 is achieved with: - Change the pybind11 wrap to point to the mainline pybdind11 version - Change the meson.build file to use a system-installed pybind11 if available, and use the pybind11 subproject as a fallback. The fallback is there as a convenience, as pybind11 may not be available in pre-packaged form in all environments. Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> --- src/py/libcamera/meson.build | 11 ++-- src/py/libcamera/py_camera_manager.h | 2 +- src/py/libcamera/py_color_space.cpp | 2 +- src/py/libcamera/py_controls_generated.cpp.in | 2 +- src/py/libcamera/py_enums.cpp | 2 +- src/py/libcamera/py_formats_generated.cpp.in | 2 +- src/py/libcamera/py_geometry.cpp | 2 +- src/py/libcamera/py_helpers.h | 2 +- src/py/libcamera/py_main.cpp | 52 +++++++++++++++++-- .../libcamera/py_properties_generated.cpp.in | 2 +- src/py/libcamera/py_transform.cpp | 2 +- subprojects/.gitignore | 2 +- subprojects/pybind11.wrap | 18 ++++--- 13 files changed, 76 insertions(+), 25 deletions(-)