libcamera: ipa_proxy: search for proxy in build tree

When libcamera is built and tested before installing, it will
be unable to locate the path to proxy workers, or previously
installed files in the system path may be incorrect to load.

Hence, when libcamera is not installed, but is running from a build
tree, identify the location of that tree by using libcameraPath(), and
from that point add relative path to the proxy workers directory.

Signed-off-by: Kaaira Gupta <kgupta@es.iitr.ac.in>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/libcamera/ipa_proxy.cpp

@@ -91,7 +91,28 @@ std::string IPAProxy::resolvePath(const std::string &file) const
 		}
 	}
 
-	/* Try finding the exec target from the install directory. */
+	/*
+	 * When libcamera is used before it is installed, load proxy workers
+	 * from the same build directory as the libcamera directory itself.
+	 * 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";
+
+		LOG(IPAProxy, Info)
+			<< "libcamera is not installed. Loading proxy workers from'"
+			<< ipaProxyDir << "'";
+
+		std::string proxyPath = ipaProxyDir + proxyFile;
+		if (!access(proxyPath.c_str(), X_OK))
+			return proxyPath;
+
+		return std::string();
+	}
+
+	/* Else try finding the exec target from the install directory. */
 	std::string proxyPath = std::string(IPA_PROXY_DIR) + proxyFile;
 	if (!access(proxyPath.c_str(), X_OK))
 		return proxyPath;