libcamera: device_enumerator: add DeviceMatch class

Provide a DeviceMatch class which represents all properties of a media
device a pipeline hander can specify when searching for a device to use
in its pipeline.

Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/libcamera/device_enumerator.cpp

@@ -75,4 +75,40 @@ int DeviceInfo::lookup(const std::string &name, std::string &devnode) const
 	return 0;
 }
 
+/* -----------------------------------------------------------------------------
+ * DeviceMatch
+ */
+
+DeviceMatch::DeviceMatch(const std::string &driver)
+	: driver_(driver)
+{
+}
+
+void DeviceMatch::add(const std::string &entity)
+{
+	entities_.push_back(entity);
+}
+
+bool DeviceMatch::match(const DeviceInfo *info) const
+{
+	if (driver_ != info->info().driver)
+		return false;
+
+	for (const std::string &name : entities_) {
+		bool found = false;
+
+		for (const std::string &entity : info->entities()) {
+			if (name == entity) {
+				found = true;
+				break;
+			}
+		}
+
+		if (!found)
+			return false;
+	}
+
+	return true;
+}
+
 } /* namespace libcamera */

src/libcamera/include/device_enumerator.h

@@ -39,6 +39,20 @@ private:
 	std::map<std::string, std::string> entities_;
 };
 
+class DeviceMatch
+{
+public:
+	DeviceMatch(const std::string &driver);
+
+	void add(const std::string &entity);
+
+	bool match(const DeviceInfo *info) const;
+
+private:
+	std::string driver_;
+	std::vector<std::string> entities_;
+};
+
 } /* namespace libcamera */
 
 #endif	/* __LIBCAMERA_DEVICE_ENUMERATOR_H__ */