cam: Extract option parser to separate file

And turn it into an OptionsParser object.

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

5 files changed, 341 insertions, 145 deletions

diff --git a/src/cam/cam.cpp b/src/cam/cam.cpp
deleted file mode 100644
index 0f795be7..00000000
--- a/src/cam/cam.cpp
+++ /dev/null
@@ -1,144 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/*
- * Copyright (C) 2019, Google Inc.
- *
- * main.cpp - cam-ctl a tool to interact with the library
- */
-
-#include <getopt.h>
-#include <iomanip>
-#include <iostream>
-#include <map>
-#include <string.h>
-
-#include <libcamera/libcamera.h>
-
-#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
-
-using namespace std;
-using namespace libcamera;
-
-enum Option {
-	OptCamera = 'c',
-	OptHelp = 'h',
-	OptList = 'l',
-	OptLast = 0,
-};
-
-struct OptionInfo {
-	Option id;
-	const char *name;
-	const char *arguments;
-	const char *description;
-};
-
-static struct OptionInfo option_info[] = {
-	{ OptCamera, "camera", "<camera>", "Specify which camera to operate on" },
-	{ OptHelp, "help", nullptr, "Display this help message" },
-	{ OptList, "list", nullptr, "List all cameras" },
-	{ OptLast, nullptr, nullptr, nullptr },
-};
-
-std::map<Option, std::string> options;
-
-void usage()
-{
-	struct OptionInfo *info;
-
-	cout << "Options:" << endl;
-	for (info = option_info; info->id != OptLast; info++) {
-		string arg(info->name);
-
-		if (info->arguments)
-			arg += string(" ") + info->arguments;
-
-		cout << "  -" << static_cast<char>(info->id) << " --" <<
-			setw(20) << left << arg << " - " <<
-			info->description << endl;
-	}
-}
-
-int parseOptions(int argc, char **argv)
-{
-	char short_options[ARRAY_SIZE(option_info) * 2 + 1];
-	struct option long_options[ARRAY_SIZE(option_info)];
-	struct OptionInfo *info;
-	unsigned ids = 0, idl = 0;
-
-	memset(short_options, 0, sizeof(short_options));
-	memset(long_options, 0, sizeof(long_options));
-
-	for (info = option_info; info->id != OptLast; info++) {
-		short_options[ids++] = info->id;
-		if (info->arguments)
-			short_options[ids++] = ':';
-
-		long_options[idl].name = info->name;
-		long_options[idl].has_arg =
-			info->arguments ? required_argument : no_argument;
-		long_options[idl].flag = 0;
-		long_options[idl].val = info->id;
-		idl++;
-	}
-
-	while (true) {
-		int c = getopt_long(argc, argv, short_options, long_options, nullptr);
-
-		if (c == -1)
-			break;
-
-		if (!isalpha(c))
-			return EXIT_FAILURE;
-
-		options[static_cast<Option>(c)] = optarg ? string(optarg) : "";
-	}
-
-	return 0;
-}
-
-bool optSet(Option opt)
-{
-	return options.count(opt) != 0;
-}
-
-int main(int argc, char **argv)
-{
-	int ret;
-
-	ret = parseOptions(argc, argv);
-	if (ret == EXIT_FAILURE)
-		return ret;
-
-	if (argc == 1 || optSet(OptHelp)) {
-		usage();
-		return 0;
-	}
-
-	CameraManager *cm = CameraManager::instance();
-
-	ret = cm->start();
-	if (ret) {
-		cout << "Failed to start camera manager: " << strerror(-ret) << endl;
-		return EXIT_FAILURE;
-	}
-
-	if (optSet(OptList)) {
-		cout << "Available cameras:" << endl;
-		for (const std::shared_ptr<Camera> &camera : cm->cameras())
-			cout << "- " << camera->name() << endl;
-	}
-
-	if (optSet(OptCamera)) {
-		std::shared_ptr<Camera> cam = cm->get(options[OptCamera]);
-
-		if (cam) {
-			cout << "Using camera " << cam->name() << endl;
-		} else {
-			cout << "Camera " << options[OptCamera] << " not found" << endl;
-		}
-	}
-
-	cm->stop();
-
-	return 0;
-}
diff --git a/src/cam/main.cpp b/src/cam/main.cpp
new file mode 100644
index 00000000..22211670
--- /dev/null
+++ b/src/cam/main.cpp
@@ -0,0 +1,85 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * main.cpp - cam - The libcamera swiss army knife
+ */
+
+#include <iostream>
+#include <map>
+#include <string.h>
+
+#include <libcamera/libcamera.h>
+
+#include "options.h"
+
+using namespace libcamera;
+
+OptionsParser::Options options;
+
+enum {
+	OptCamera = 'c',
+	OptHelp = 'h',
+	OptList = 'l',
+};
+
+static int parseOptions(int argc, char *argv[])
+{
+	OptionsParser parser;
+
+	parser.addOption(OptCamera, "Specify which camera to operate on",
+			 "camera", OptionsParser::ArgumentRequired,
+			 "camera");
+	parser.addOption(OptHelp, "Display this help message", "help");
+	parser.addOption(OptList, "List all cameras", "list");
+
+	options = std::move(parser.parse(argc, argv));
+	if (!options.valid())
+		return -EINVAL;
+
+	if (argc == 1 || options.isSet(OptHelp)) {
+		parser.usage();
+		return 1;
+	}
+
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	int ret;
+
+	ret = parseOptions(argc, argv);
+	if (ret < 0)
+		return EXIT_FAILURE;
+
+	CameraManager *cm = CameraManager::instance();
+
+	ret = cm->start();
+	if (ret) {
+		std::cout << "Failed to start camera manager: "
+			  << strerror(-ret) << std::endl;
+		return EXIT_FAILURE;
+	}
+
+	if (options.isSet(OptList)) {
+		std::cout << "Available cameras:" << std::endl;
+		for (const std::shared_ptr<Camera> &camera : cm->cameras())
+			std::cout << "- " << camera->name() << std::endl;
+	}
+
+	if (options.isSet(OptCamera)) {
+		std::shared_ptr<Camera> cam = cm->get(options[OptCamera]);
+
+		if (cam) {
+			std::cout << "Using camera " << cam->name() << std::endl;
+		} else {
+			std::cout << "Camera " << options[OptCamera]
+				  << " not found" << std::endl;
+		}
+	}
+
+	cm->stop();
+
+	return 0;
+}
diff --git a/src/cam/meson.build b/src/cam/meson.build
index 809a40e0..e45e5391 100644
--- a/src/cam/meson.build
+++ b/src/cam/meson.build
@@ -1,5 +1,6 @@
 cam_sources = files([
-    'cam.cpp',
+    'main.cpp',
+    'options.cpp',
 ])
 
 cam  = executable('cam', cam_sources,
diff --git a/src/cam/options.cpp b/src/cam/options.cpp
new file mode 100644
index 00000000..d391a0e5
--- /dev/null
+++ b/src/cam/options.cpp
@@ -0,0 +1,192 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * options.cpp - cam - Options parsing
+ */
+
+#include <getopt.h>
+#include <iomanip>
+#include <iostream>
+#include <string.h>
+
+#include "options.h"
+
+void OptionsParser::addOption(int opt, const char *help, const char *name,
+			      OptionArgument argument, const char *argumentName)
+{
+	/*
+	 * Options must have at least a short or long name, and a text message.
+	 * If an argument is accepted, it must be described by argumentName.
+	 */
+	if (!isalnum(opt) && !name)
+		return;
+	if (!help || help[0] == '\0')
+		return;
+	if (argument != ArgumentNone && !argumentName)
+		return;
+
+	/* Reject duplicate options. */
+	if (optionsMap_.find(opt) != optionsMap_.end())
+		return;
+
+	options_.push_back(Option({ opt, name, argument, argumentName, help }));
+	optionsMap_[opt] = &options_.back();
+}
+
+OptionsParser::Options OptionsParser::parse(int argc, char **argv)
+{
+	OptionsParser::Options options;
+
+	/*
+	 * Allocate short and long options arrays large enough to contain all
+	 * options.
+	 */
+	char shortOptions[options_.size() * 3 + 2] = {};
+	struct option longOptions[options_.size() + 1] = {};
+	unsigned int ids = 0;
+	unsigned int idl = 0;
+
+	shortOptions[ids++] = ':';
+
+	for (const Option &option : options_) {
+		if (option.hasShortOption()) {
+			shortOptions[ids++] = option.opt;
+			if (option.argument != ArgumentNone)
+				shortOptions[ids++] = ':';
+			if (option.argument == ArgumentOptional)
+				shortOptions[ids++] = ':';
+		}
+
+		if (option.hasLongOption()) {
+			longOptions[idl].name = option.name;
+
+			switch (option.argument) {
+			case ArgumentNone:
+				longOptions[idl].has_arg = no_argument;
+				break;
+			case ArgumentRequired:
+				longOptions[idl].has_arg = required_argument;
+				break;
+			case ArgumentOptional:
+				longOptions[idl].has_arg = optional_argument;
+				break;
+			}
+
+			longOptions[idl].flag = 0;
+			longOptions[idl].val = option.opt;
+			idl++;
+		}
+	}
+
+	opterr = 0;
+
+	while (true) {
+		int c = getopt_long(argc, argv, shortOptions, longOptions, nullptr);
+
+		if (c == -1)
+			break;
+
+		if (c == '?' || c == ':') {
+			if (c == '?')
+				std::cerr << "Invalid option ";
+			else
+				std::cerr << "Missing argument for option ";
+			std::cerr << argv[optind - 1] << std::endl;
+
+			usage();
+			options.clear();
+			break;
+		}
+
+		options.values_[c] = optarg ? optarg : "";
+	}
+
+	return std::move(options);
+}
+
+void OptionsParser::usage()
+{
+	std::cerr << "Options:" << std::endl;
+
+	unsigned int indent = 0;
+
+	for (const Option &option : options_) {
+		unsigned int length = 14;
+		if (option.hasLongOption())
+			length += 2 + strlen(option.name);
+		if (option.argument != ArgumentNone)
+			length += 1 + strlen(option.argumentName);
+		if (option.argument == ArgumentOptional)
+			length += 2;
+
+		if (length > indent)
+			indent = length;
+	}
+
+	indent = (indent + 7) / 8 * 8;
+
+	for (const Option &option : options_) {
+		std::string argument;
+		if (option.hasShortOption())
+			argument = std::string("  -")
+				 + static_cast<char>(option.opt);
+		else
+			argument = "    ";
+
+		if (option.hasLongOption()) {
+			if (option.hasShortOption())
+				argument += ", ";
+			else
+				argument += "  ";
+			argument += std::string("--") + option.name;
+		};
+
+		if (option.argument != ArgumentNone) {
+			argument += std::string(" ");
+			if (option.argument == ArgumentOptional)
+				argument += "[";
+			argument += option.argumentName;
+			if (option.argument == ArgumentOptional)
+				argument += "]";
+		}
+
+		std::cerr << std::setw(indent) << std::left << argument;
+		std::cerr << option.help << std::endl;
+	}
+}
+
+OptionsParser::Options::Options()
+{
+}
+
+OptionsParser::Options::Options(Options &&other)
+	: values_(std::move(other.values_))
+{
+}
+
+OptionsParser::Options &OptionsParser::Options::operator=(Options &&other)
+{
+	values_ = other.values_;
+	return *this;
+}
+
+bool OptionsParser::Options::valid() const
+{
+	return !values_.empty();
+}
+
+bool OptionsParser::Options::isSet(int opt) const
+{
+	return values_.find(opt) != values_.end();
+}
+
+const std::string &OptionsParser::Options::operator[](int opt) const
+{
+	return values_.find(opt)->second;
+}
+
+void OptionsParser::Options::clear()
+{
+	values_.clear();
+}
diff --git a/src/cam/options.h b/src/cam/options.h
new file mode 100644
index 00000000..88336dfe
--- /dev/null
+++ b/src/cam/options.h
@@ -0,0 +1,62 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * options.h - cam - Options parsing
+ */
+#ifndef __CAM_OPTIONS_H__
+#define __CAM_OPTIONS_H__
+
+#include <ctype.h>
+#include <map>
+#include <vector>
+
+class OptionsParser
+{
+public:
+	enum OptionArgument {
+		ArgumentNone,
+		ArgumentRequired,
+		ArgumentOptional,
+	};
+
+	class Options {
+	public:
+		Options();
+		Options(Options &&other);
+		Options &operator=(Options &&other);
+
+		bool valid() const;
+		bool isSet(int opt) const;
+		const std::string &operator[](int opt) const;
+
+	private:
+		friend class OptionsParser;
+		std::map<int, std::string> values_;
+		void clear();
+	};
+
+	void addOption(int opt, const char *help, const char *name = nullptr,
+		       OptionArgument argument = ArgumentNone,
+		       const char *argumentName = nullptr);
+
+	Options parse(int argc, char *argv[]);
+	void usage();
+
+private:
+	struct Option {
+		int opt;
+		const char *name;
+		OptionArgument argument;
+		const char *argumentName;
+		const char *help;
+
+		bool hasShortOption() const { return isalnum(opt); }
+		bool hasLongOption() const { return name != nullptr; }
+	};
+
+	std::vector<Option> options_;
+	std::map<unsigned int, Option *> optionsMap_;
+};
+
+#endif /* __CAM_OPTIONS_H__ */