[libcamera-devel] [PATCH LIBCAMERA v5] libcamera: utils: adapt libcameraPath to match use cases

[Laurent Pinchart]

Patch applied and pushed, thank you ! Don't forget to record it in your
contributions.

On Thu, Mar 19, 2020 at 09:31:40PM +0530, 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 libcameraBuildPath() which
> combines their functions and returns the root of the build sources
> when the library has not been installed, but is running from the build
> tree, thereby making call sites simpler.
> 
> When the library is installed, libcameraBuildPath() will return an empty
> string.
> 
> Make changes in the call sites accordingly.
> 
> Signed-off-by: Kaaira Gupta <kgupta at es.iitr.ac.in>
> ---
> Changes since v4:
> 	- Updated documentation of libcameraBuildPath() 
> 
> Changes since v3:
>         - removed isLibcameraInstalled() from utils.h
>         - reformatted the code to reduce indentation of the code that
>           implements actual logic, also, to catch the errors
>           immediately.
>         - changes in spellings and whitespaces in commit messages.
> 
> Changes since v2:
>         - rename subject line and add necessary details in commit
>           message.
>         - Solve whitespace issues.
>         - specify the final 'slash' for directory path in return
>           statement itself.
> 
> Changes since v1:
>         - rename function to libcameraBuildPath() instead, and return
>           the root of libcamera source, and not the source directory
>           root.
>         - Return empty string instead of nullptr when ret==0
> 
>  src/libcamera/include/utils.h |  4 +---
>  src/libcamera/ipa_manager.cpp |  5 +++--
>  src/libcamera/ipa_proxy.cpp   |  6 +++---
>  src/libcamera/utils.cpp       | 26 ++++++++++++++++++--------
>  4 files changed, 25 insertions(+), 16 deletions(-)
> 
> diff --git a/src/libcamera/include/utils.h b/src/libcamera/include/utils.h
> index bc96e79..cfa620f 100644
> --- a/src/libcamera/include/utils.h
> +++ b/src/libcamera/include/utils.h
> @@ -143,9 +143,7 @@ private:
>  
>  details::StringSplitter split(const std::string &str, const std::string &delim);
>  
> -bool isLibcameraInstalled();
> -
> -std::string libcameraPath();
> +std::string libcameraBuildPath();
>  
>  } /* namespace utils */
>  
> diff --git a/src/libcamera/ipa_manager.cpp b/src/libcamera/ipa_manager.cpp
> index 0bd280c..bcaae35 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 root = utils::libcameraBuildPath();
> +	if (!root.empty()) {
> +		std::string ipaBuildPath = root + "src/ipa";
>  		constexpr int maxDepth = 1;
>  
>  		LOG(IPAManager, Info)
> diff --git a/src/libcamera/ipa_proxy.cpp b/src/libcamera/ipa_proxy.cpp
> index 2f866cc..5fd88a4 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 root = utils::libcameraBuildPath();
> +	if (!root.empty()) {
> +		std::string ipaProxyDir = root + "src/libcamera/proxy/worker";
>  
>  		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..58ee7cc 100644
> --- a/src/libcamera/utils.cpp
> +++ b/src/libcamera/utils.cpp
> @@ -340,23 +340,33 @@ bool isLibcameraInstalled()
>  }
>  
>  /**
> - * \brief Identify the libcamera.so path
> + * \brief Retrieve the path to the build directory
>   *
> - * This function locates the running libcamera.so and returns its full path,
> - * including the file name.
> + * During development, it is useful to run libcamera binaries directly from the
> + * build directory without installing them. This function helps components that
> + * need to locate resources, such as IPA modules or IPA proxy workers, by
> + * providing them with the path to the root of the build directory. Callers can
> + * then use it to complement or override searches in system-wide directories.
>   *
> - * \return A string stating the path
> + * If libcamera has been installed, the build directory path is not available
> + * and this function returns an empty string.
> + *
> + * \return The path to the build directory if running from a build, or an empty
> + * string otherwise
>   */
> -std::string libcameraPath()
> +std::string libcameraBuildPath()
>  {
> +	if (isLibcameraInstalled())
> +		return std::string();
> +
>  	Dl_info info;
>  
>  	/* Look up our own symbol. */
> -	int ret = dladdr(reinterpret_cast<void *>(libcameraPath), &info);
> +	int ret = dladdr(reinterpret_cast<void *>(libcameraBuildPath), &info);
>  	if (ret == 0)
> -		return nullptr;
> +		return std::string();
>  
> -	return info.dli_fname;
> +	return dirname(info.dli_fname) + "/../../";
>  }
>  
>  } /* namespace utils */

-- 
Regards,

Laurent Pinchart