[libcamera-devel] [PATCH LIBCAMERA] libcamera: utils: merge isLibcamerainstalled with libcameraPath

[Kaaira Gupta]

On Thu, Mar 19, 2020 at 10:36:14AM +0000, Kieran Bingham wrote:
> Hi Kaaira,
> 
> On 19/03/2020 09:54, Kaaira Gupta wrote:
> > The two callers of functions libcameraPath() and isLibcameraInstalled()
> > end up using the same process and finally use the path with
> > libcamera.so. Hence write a function libcameraSourcePath() which
> > combines their functions, thereby making call sites simpler.
> > 
> > Signed-off-by: Kaaira Gupta <kgupta at es.iitr.ac.in>
> > ---
> >  src/libcamera/include/utils.h |  2 +-
> >  src/libcamera/ipa_manager.cpp |  5 +++--
> >  src/libcamera/ipa_proxy.cpp   |  6 +++---
> >  src/libcamera/utils.cpp       | 20 +++++++++++---------
> >  4 files changed, 18 insertions(+), 15 deletions(-)
> > 
> > diff --git a/src/libcamera/include/utils.h b/src/libcamera/include/utils.h
> > index bc96e79..2cff15e 100644
> > --- a/src/libcamera/include/utils.h
> > +++ b/src/libcamera/include/utils.h
> > @@ -145,7 +145,7 @@ details::StringSplitter split(const std::string &str, const std::string &delim);
> >  
> >  bool isLibcameraInstalled();
> >  
> > -std::string libcameraPath();
> > +std::string libcameraSourcePath();
> >  
> >  } /* namespace utils */
> >  
> > diff --git a/src/libcamera/ipa_manager.cpp b/src/libcamera/ipa_manager.cpp
> > index 0bd280c..cf9b6e7 100644
> > --- a/src/libcamera/ipa_manager.cpp
> > +++ b/src/libcamera/ipa_manager.cpp
> > @@ -119,8 +119,9 @@ IPAManager::IPAManager()
> >  	 * path for the IPA from that point. We need to recurse one level of
> >  	 * sub-directories to match the build tree.
> >  	 */
> > -	if (!utils::isLibcameraInstalled()) {
> > -		std::string ipaBuildPath = utils::dirname(utils::libcameraPath()) + "/../ipa";
> > +	std::string libPath = utils::libcameraSourcePath();
> > +	if (!libPath.empty()) {
> > +		std::string ipaBuildPath = libPath + "/../ipa";
> 
> 
> I wonder if we should make utils::libcameraSourcePath return the root of
> the libcamera sources so that any users take a relative path from the root?
> 
> That might make things clearer or more consistent as then the
> ipaBuildPath would become:

Yes, that will make things more clean. I have updated the patch.

> 
>   std::string ipaBuildPath = root + "/src/ipa";
> 
> What do you think?
> 
> if we do change to return the 'root', it would be a 'Build' directory
> root not a 'Source', so I think we might have to reconsider the name of
> the function too.
> 
> >  		constexpr int maxDepth = 1;
> >  
> >  		LOG(IPAManager, Info)
> > diff --git a/src/libcamera/ipa_proxy.cpp b/src/libcamera/ipa_proxy.cpp
> > index 2f866cc..e9b7568 100644
> > --- a/src/libcamera/ipa_proxy.cpp
> > +++ b/src/libcamera/ipa_proxy.cpp
> > @@ -97,9 +97,9 @@ std::string IPAProxy::resolvePath(const std::string &file) const
> >  	 * This requires identifying the path of the libcamera.so, and
> >  	 * referencing a relative path for the proxy workers from that point.
> >  	 */
> > -	if (!utils::isLibcameraInstalled()) {
> > -		std::string ipaProxyDir = utils::dirname(utils::libcameraPath())
> > -					  + "/proxy/worker";
> > +	std::string libPath = utils::libcameraSourcePath();
> > +	if (!libPath.empty()) {
> > +		std::string ipaProxyDir = libPath + "/proxy/worker";
> 
> Of course, this would then become a bit longer:
> 
> std::string ipaProxyDir = libPath + "src/libcamera/proxy/worker";
> 
> But I think it might make the intent clearer for both locations?
> 
> 
> >  
> >  		LOG(IPAProxy, Info)
> >  			<< "libcamera is not installed. Loading proxy workers from'"
> > diff --git a/src/libcamera/utils.cpp b/src/libcamera/utils.cpp
> > index 7e118fa..8212d3e 100644
> > --- a/src/libcamera/utils.cpp
> > +++ b/src/libcamera/utils.cpp
> > @@ -347,16 +347,18 @@ bool isLibcameraInstalled()
> >   *
> >   * \return A string stating the path
> >   */
> > -std::string libcameraPath()
> > +std::string libcameraSourcePath()
> >  {
> > -	Dl_info info;
> > -
> > -	/* Look up our own symbol. */
> > -	int ret = dladdr(reinterpret_cast<void *>(libcameraPath), &info);
> > -	if (ret == 0)
> > -		return nullptr;
> > -
> > -	return info.dli_fname;
> > +	if (!utils::isLibcameraInstalled()) {
> 
> Because we are 'in' the utils:: namespace here, I don't think you need
> to explicitly state 'utils::' to call isLibcameraInstalled.
> 
> The compiler will find the function without it.
> 
> > +		Dl_info info;
> > +		/* Look up our own symbol. */
> > +		int ret = dladdr(reinterpret_cast<void *>(libcameraSourcePath), &info);
> > +		if (ret == 0)
> > +			return nullptr;
> > +
> > +		return utils::dirname(info.dli_fname);
> 
> If you drop the 'else' as stated below, you can invert this if, to
> 
>  if (ret)
> 	return utils::dirname(info.dli_fname);
> 
> and let the error case fall through to the return std::string(); below
> which is better than returning a nullptr anyway, as the callers check
> this returned string for .empty() (so returning a nullptr is bad).
> 
> > +	} else
> > +		return std::string();
> 
> You can drop the 'else', and put the return std::string(); as the last
> statement of the function.
> 
> 
> >  }
> >  
> >  } /* namespace utils */
> > 
> 
> -- 
> Regards
> --
> Kieran