cam: Add helper class to parse stream configuration

Create a new helper class StreamKeyValueParser to parse command line
options describing stream configurations. The goal is to share this new
class between cam and qcam.

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

src/cam/meson.build

@@ -4,6 +4,7 @@ cam_sources = files([
     'event_loop.cpp',
     'main.cpp',
     'options.cpp',
+    'stream_options.cpp',
 ])
 
 cam  = executable('cam', cam_sources,

src/cam/stream_options.cpp

@@ -0,0 +1,129 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2020, Raspberry Pi (Trading) Ltd.
+ *
+ * stream_options.cpp - Helper to parse options for streams
+ */
+#include "stream_options.h"
+
+#include <iostream>
+
+using namespace libcamera;
+
+StreamKeyValueParser::StreamKeyValueParser()
+{
+	addOption("role", OptionString,
+		  "Role for the stream (viewfinder, video, still, stillraw)",
+		  ArgumentRequired);
+	addOption("width", OptionInteger, "Width in pixels",
+		  ArgumentRequired);
+	addOption("height", OptionInteger, "Height in pixels",
+		  ArgumentRequired);
+	addOption("pixelformat", OptionInteger, "Pixel format",
+		  ArgumentRequired);
+}
+
+KeyValueParser::Options StreamKeyValueParser::parse(const char *arguments)
+{
+	KeyValueParser::Options options = KeyValueParser::parse(arguments);
+	StreamRole role;
+
+	if (options.valid() && options.isSet("role") &&
+	    !parseRole(&role, options)) {
+		std::cerr << "Unknown stream role "
+			  << options["role"].toString() << std::endl;
+		options.invalidate();
+	}
+
+	return options;
+}
+
+StreamRoles StreamKeyValueParser::roles(const OptionValue &values)
+{
+	const std::vector<OptionValue> &streamParameters = values.toArray();
+
+	/* If no configuration values to examine default to viewfinder. */
+	if (streamParameters.empty())
+		return { StreamRole::Viewfinder };
+
+	StreamRoles roles;
+	for (auto const &value : streamParameters) {
+		KeyValueParser::Options opts = value.toKeyValues();
+		StreamRole role;
+
+		/* If role is invalid or not set default to viewfinder. */
+		if (!parseRole(&role, value))
+			role = StreamRole::Viewfinder;
+
+		roles.push_back(role);
+	}
+
+	return roles;
+}
+
+int StreamKeyValueParser::updateConfiguration(CameraConfiguration *config,
+					      const OptionValue &values)
+{
+	const std::vector<OptionValue> &streamParameters = values.toArray();
+
+	if (!config) {
+		std::cerr << "No configuration provided" << std::endl;
+		return -EINVAL;
+	}
+
+	/* If no configuration values nothing to do. */
+	if (!streamParameters.size())
+		return 0;
+
+	if (config->size() != streamParameters.size()) {
+		std::cerr
+			<< "Number of streams in configuration "
+			<< config->size()
+			<< " does not match number of streams parsed "
+			<< streamParameters.size()
+			<< std::endl;
+		return -EINVAL;
+	}
+
+	unsigned int i = 0;
+	for (auto const &value : streamParameters) {
+		KeyValueParser::Options opts = value.toKeyValues();
+		StreamConfiguration &cfg = config->at(i++);
+
+		if (opts.isSet("width") && opts.isSet("height")) {
+			cfg.size.width = opts["width"];
+			cfg.size.height = opts["height"];
+		}
+
+		/* \todo Translate 4CC string to pixelformat with modifier. */
+		if (opts.isSet("pixelformat"))
+			cfg.pixelFormat = PixelFormat(opts["pixelformat"]);
+	}
+
+	return 0;
+}
+
+bool StreamKeyValueParser::parseRole(StreamRole *role,
+				     const KeyValueParser::Options &options)
+{
+	if (!options.isSet("role"))
+		return false;
+
+	std::string name = options["role"].toString();
+
+	if (name == "viewfinder") {
+		*role = StreamRole::Viewfinder;
+		return true;
+	} else if (name == "video") {
+		*role = StreamRole::VideoRecording;
+		return true;
+	} else if (name == "still") {
+		*role = StreamRole::StillCapture;
+		return true;
+	} else if (name == "stillraw") {
+		*role = StreamRole::StillCaptureRaw;
+		return true;
+	}
+
+	return false;
+}

src/cam/stream_options.h

@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2020, Raspberry Pi (Trading) Ltd.
+ *
+ * stream_options.h - Helper to parse options for streams
+ */
+#ifndef __CAM_STREAM_OPTIONS_H__
+#define __CAM_STREAM_OPTIONS_H__
+
+#include <libcamera/camera.h>
+
+#include "options.h"
+
+using namespace libcamera;
+
+class StreamKeyValueParser : public KeyValueParser
+{
+public:
+	StreamKeyValueParser();
+
+	KeyValueParser::Options parse(const char *arguments) override;
+
+	static StreamRoles roles(const OptionValue &values);
+	static int updateConfiguration(CameraConfiguration *config,
+				       const OptionValue &values);
+
+private:
+	static bool parseRole(StreamRole *role,
+			      const KeyValueParser::Options &options);
+};
+
+#endif /* __CAM_STREAM_OPTIONS_H__ */