[libcamera-devel] [PATCH 5/6] android: camera_device: Load make and model from platform settings

[Laurent Pinchart]

Hi Paul,

Thank you for the patch.

On Fri, Jan 15, 2021 at 03:24:52PM +0100, Jacopo Mondi wrote:
> On Thu, Jan 14, 2021 at 07:40:34PM +0900, Paul Elder wrote:
> > In ChromeOS the camera make and model is saved in
> > /var/cache/camera/camera.prop. Load and save these values at
> > construction time, if available.
> >
> > Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
> > ---
> >  src/android/camera_device.cpp | 30 ++++++++++++++++++++++++++++++
> >  src/android/camera_device.h   |  5 +++++
> >  2 files changed, 35 insertions(+)
> >
> > diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
> > index d2a8e876..ed47c7cd 100644
> > --- a/src/android/camera_device.cpp
> > +++ b/src/android/camera_device.cpp
> > @@ -18,6 +18,7 @@
> >  #include <libcamera/formats.h>
> >  #include <libcamera/property_ids.h>
> >
> > +#include "libcamera/internal/file.h"
> >  #include "libcamera/internal/formats.h"
> >  #include "libcamera/internal/log.h"
> >  #include "libcamera/internal/utils.h"
> > @@ -344,6 +345,35 @@ CameraDevice::CameraDevice(unsigned int id, const std::shared_ptr<Camera> &camer
> >  	 *  streamConfiguration.
> >  	 */
> >  	maxJpegBufferSize_ = 13 << 20; /* 13631488 from USB HAL */
> > +
> > +	cameraMake_ = "libcamera";
> > +	cameraModel_ = "cameraModel";
> 
> You know, library-wide support for configuration files should land
> somewhen soon. I would rather hardcode the above values with a \todo
> entry.
> 
> Or does this make any test un-happy ?

Chrome OS expects the value to be taken from
/var/cache/camera/camera.prop, so I think it makes sense to do so on
that platform.

For Android we need something else, possibly a custom configuration
file, or an Android-specific file or API. I'd record this in a todo.

> > +
> > +	File prop("/var/cache/camera/camera.prop");
> > +	if (!prop.open(File::ReadOnly))
> > +		return;
> > +
> > +	size_t fileSize = prop.size();
> > +	if (fileSize <= 0)
> > +		return;
> > +
> > +	std::vector<uint8_t> buf(fileSize);
> > +	if (prop.read(buf) < 0)
> > +		return;
> > +
> > +	std::string fileContents(buf.begin(), buf.end());
> > +	for (const auto &line : utils::split(fileContents, "\n")) {

This is a bit inefficient, as utils::split() makes a copy of
fileContents, which itself makes a copy of buf. The configuration file
isn't expected to be large so it may be OK, even if it's not great.
Another option would be to use std::ifstream() and std::getline(), which
should be fairly simple.

> > +		off_t delimPos = line.find("=");
> > +		if (delimPos == std::string::npos)
> > +			continue;
> > +		std::string key = line.substr(0, delimPos);
> > +		std::string val = line.substr(delimPos + 1, line.size());

You can drop the second argument to substr().

> > +
> > +		if (!key.compare("ro.product.model"))
> > +			cameraModel_ = val;
> > +		if (!key.compare("ro.product.manufacturer"))
> > +			cameraMake_ = val;
> > +	}

Should we move all this to a separate private function to avoid
cluttering the constructor ?

> >  }
> >
> >  CameraDevice::~CameraDevice()
> > diff --git a/src/android/camera_device.h b/src/android/camera_device.h
> > index 0874c80f..a285d0a1 100644
> > --- a/src/android/camera_device.h
> > +++ b/src/android/camera_device.h
> > @@ -56,6 +56,8 @@ public:
> >  		return config_.get();
> >  	}
> >
> > +	const std::string &cameraMake() const { return cameraMake_; }
> > +	const std::string &cameraModel() const { return cameraModel_; }
> >  	int facing() const { return facing_; }
> >  	int orientation() const { return orientation_; }
> >  	unsigned int maxJpegBufferSize() const { return maxJpegBufferSize_; }
> > @@ -127,6 +129,9 @@ private:
> >  	std::map<int, libcamera::PixelFormat> formatsMap_;
> >  	std::vector<CameraStream> streams_;
> >
> > +	std::string cameraMake_;
> > +	std::string cameraModel_;
> > +
> >  	int facing_;
> >  	int orientation_;
> >

-- 
Regards,

Laurent Pinchart