From a8113fb3a89984cc65d51436480cee45b60543e8 Mon Sep 17 00:00:00 2001
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Date: Thu, 20 Oct 2022 01:25:45 +0300
Subject: apps: Share common source between applications

Multiple source files in the src/apps/cam/ directory are used by cam,
qcam and lc-compliance. They are compiled separately for each
application. Move them to a new src/apps/common/ directory and compile
them in a static library to decrease the number of compilation
operations.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
---
 src/apps/common/options.cpp | 1141 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 1141 insertions(+)
 create mode 100644 src/apps/common/options.cpp

(limited to 'src/apps/common/options.cpp')

diff --git a/src/apps/common/options.cpp b/src/apps/common/options.cpp
new file mode 100644
index 00000000..4f7e8691
--- /dev/null
+++ b/src/apps/common/options.cpp
@@ -0,0 +1,1141 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * options.cpp - cam - Options parsing
+ */
+
+#include <assert.h>
+#include <getopt.h>
+#include <iomanip>
+#include <iostream>
+#include <string.h>
+
+#include "options.h"
+
+/**
+ * \enum OptionArgument
+ * \brief Indicate if an option takes an argument
+ *
+ * \var OptionArgument::ArgumentNone
+ * \brief The option doesn't accept any argument
+ *
+ * \var OptionArgument::ArgumentRequired
+ * \brief The option requires an argument
+ *
+ * \var OptionArgument::ArgumentOptional
+ * \brief The option accepts an optional argument
+ */
+
+/**
+ * \enum OptionType
+ * \brief The type of argument for an option
+ *
+ * \var OptionType::OptionNone
+ * \brief No argument type, used for options that take no argument
+ *
+ * \var OptionType::OptionInteger
+ * \brief Integer argument type, with an optional base prefix (`0` for base 8,
+ * `0x` for base 16, none for base 10)
+ *
+ * \var OptionType::OptionString
+ * \brief String argument
+ *
+ * \var OptionType::OptionKeyValue
+ * \brief key=value list argument
+ */
+
+/* -----------------------------------------------------------------------------
+ * Option
+ */
+
+/**
+ * \struct Option
+ * \brief Store metadata about an option
+ *
+ * \var Option::opt
+ * \brief The option identifier
+ *
+ * \var Option::type
+ * \brief The type of the option argument
+ *
+ * \var Option::name
+ * \brief The option name
+ *
+ * \var Option::argument
+ * \brief Whether the option accepts an optional argument, a mandatory
+ * argument, or no argument at all
+ *
+ * \var Option::argumentName
+ * \brief The argument name used in the help text
+ *
+ * \var Option::help
+ * \brief The help text (may be a multi-line string)
+ *
+ * \var Option::keyValueParser
+ * \brief For options of type OptionType::OptionKeyValue, the key-value parser
+ * to parse the argument
+ *
+ * \var Option::isArray
+ * \brief Whether the option can appear once or multiple times
+ *
+ * \var Option::parent
+ * \brief The parent option
+ *
+ * \var Option::children
+ * \brief List of child options, storing all options whose parent is this option
+ *
+ * \fn Option::hasShortOption()
+ * \brief Tell if the option has a short option specifier (e.g. `-f`)
+ * \return True if the option has a short option specifier, false otherwise
+ *
+ * \fn Option::hasLongOption()
+ * \brief Tell if the option has a long option specifier (e.g. `--foo`)
+ * \return True if the option has a long option specifier, false otherwise
+ */
+struct Option {
+	int opt;
+	OptionType type;
+	const char *name;
+	OptionArgument argument;
+	const char *argumentName;
+	const char *help;
+	KeyValueParser *keyValueParser;
+	bool isArray;
+	Option *parent;
+	std::list<Option> children;
+
+	bool hasShortOption() const { return isalnum(opt); }
+	bool hasLongOption() const { return name != nullptr; }
+	const char *typeName() const;
+	std::string optionName() const;
+};
+
+/**
+ * \brief Retrieve a string describing the option type
+ * \return A string describing the option type
+ */
+const char *Option::typeName() const
+{
+	switch (type) {
+	case OptionNone:
+		return "none";
+
+	case OptionInteger:
+		return "integer";
+
+	case OptionString:
+		return "string";
+
+	case OptionKeyValue:
+		return "key=value";
+	}
+
+	return "unknown";
+}
+
+/**
+ * \brief Retrieve a string describing the option name, with leading dashes
+ * \return A string describing the option name, as a long option identifier
+ * (double dash) if the option has a name, or a short option identifier (single
+ * dash) otherwise
+ */
+std::string Option::optionName() const
+{
+	if (name)
+		return "--" + std::string(name);
+	else
+		return "-" + std::string(1, opt);
+}
+
+/* -----------------------------------------------------------------------------
+ * OptionBase<T>
+ */
+
+/**
+ * \class template<typename T> OptionBase
+ * \brief Container to store the values of parsed options
+ * \tparam T The type through which options are identified
+ *
+ * The OptionsBase class is generated by a parser (either OptionsParser or
+ * KeyValueParser) when parsing options. It stores values for all the options
+ * found, and exposes accessor functions to retrieve them. The options are
+ * accessed through an identifier to type \a T, which is an int referencing an
+ * Option::opt for OptionsParser, or a std::string referencing an Option::name
+ * for KeyValueParser.
+ */
+
+/**
+ * \fn OptionsBase::OptionsBase()
+ * \brief Construct an OptionsBase instance
+ *
+ * The constructed instance is initially invalid, and will be populated by the
+ * options parser.
+ */
+
+/**
+ * \brief Tell if the stored options list is empty
+ * \return True if the container is empty, false otherwise
+ */
+template<typename T>
+bool OptionsBase<T>::empty() const
+{
+	return values_.empty();
+}
+
+/**
+ * \brief Tell if the options parsing completed successfully
+ * \return True if the container is returned after successfully parsing
+ * options, false if it is returned after an error was detected during parsing
+ */
+template<typename T>
+bool OptionsBase<T>::valid() const
+{
+	return valid_;
+}
+
+/**
+ * \brief Tell if the option \a opt is specified
+ * \param[in] opt The option to search for
+ * \return True if the \a opt option is set, false otherwise
+ */
+template<typename T>
+bool OptionsBase<T>::isSet(const T &opt) const
+{
+	return values_.find(opt) != values_.end();
+}
+
+/**
+ * \brief Retrieve the value of option \a opt
+ * \param[in] opt The option to retrieve
+ * \return The value of option \a opt if found, an empty OptionValue otherwise
+ */
+template<typename T>
+const OptionValue &OptionsBase<T>::operator[](const T &opt) const
+{
+	static const OptionValue empty;
+
+	auto it = values_.find(opt);
+	if (it != values_.end())
+		return it->second;
+	return empty;
+}
+
+/**
+ * \brief Mark the container as invalid
+ *
+ * This function can be used in a key-value parser's override of the
+ * KeyValueParser::parse() function to mark the returned options as invalid if
+ * a validation error occurs.
+ */
+template<typename T>
+void OptionsBase<T>::invalidate()
+{
+	valid_ = false;
+}
+
+template<typename T>
+bool OptionsBase<T>::parseValue(const T &opt, const Option &option,
+				const char *arg)
+{
+	OptionValue value;
+
+	switch (option.type) {
+	case OptionNone:
+		break;
+
+	case OptionInteger:
+		unsigned int integer;
+
+		if (arg) {
+			char *endptr;
+			integer = strtoul(arg, &endptr, 0);
+			if (*endptr != '\0')
+				return false;
+		} else {
+			integer = 0;
+		}
+
+		value = OptionValue(integer);
+		break;
+
+	case OptionString:
+		value = OptionValue(arg ? arg : "");
+		break;
+
+	case OptionKeyValue:
+		KeyValueParser *kvParser = option.keyValueParser;
+		KeyValueParser::Options keyValues = kvParser->parse(arg);
+		if (!keyValues.valid())
+			return false;
+
+		value = OptionValue(keyValues);
+		break;
+	}
+
+	if (option.isArray)
+		values_[opt].addValue(value);
+	else
+		values_[opt] = value;
+
+	return true;
+}
+
+template class OptionsBase<int>;
+template class OptionsBase<std::string>;
+
+/* -----------------------------------------------------------------------------
+ * KeyValueParser
+ */
+
+/**
+ * \class KeyValueParser
+ * \brief A specialized parser for list of key-value pairs
+ *
+ * The KeyValueParser is an options parser for comma-separated lists of
+ * `key=value` pairs. The supported keys are added to the parser with
+ * addOption(). A given key can only appear once in the parsed list.
+ *
+ * Instances of this class can be passed to the OptionsParser::addOption()
+ * function to create options that take key-value pairs as an option argument.
+ * Specialized versions of the key-value parser can be created by inheriting
+ * from this class, to pre-build the options list in the constructor, and to add
+ * custom validation by overriding the parse() function.
+ */
+
+/**
+ * \class KeyValueParser::Options
+ * \brief An option list generated by the key-value parser
+ *
+ * This is a specialization of OptionsBase with the option reference type set to
+ * std::string.
+ */
+
+KeyValueParser::KeyValueParser() = default;
+KeyValueParser::~KeyValueParser() = default;
+
+/**
+ * \brief Add a supported option to the parser
+ * \param[in] name The option name, corresponding to the key name in the
+ * key=value pair. The name shall be unique.
+ * \param[in] type The type of the value in the key=value pair
+ * \param[in] help The help text
+ * \param[in] argument Whether the value is optional, mandatory or not allowed.
+ * Shall be ArgumentNone if \a type is OptionNone.
+ *
+ * \sa OptionsParser
+ *
+ * \return True if the option was added successfully, false if an error
+ * occurred.
+ */
+bool KeyValueParser::addOption(const char *name, OptionType type,
+			       const char *help, OptionArgument argument)
+{
+	if (!name)
+		return false;
+	if (!help || help[0] == '\0')
+		return false;
+	if (argument != ArgumentNone && type == OptionNone)
+		return false;
+
+	/* Reject duplicate options. */
+	if (optionsMap_.find(name) != optionsMap_.end())
+		return false;
+
+	optionsMap_[name] = Option({ 0, type, name, argument, nullptr,
+				     help, nullptr, false, nullptr, {} });
+	return true;
+}
+
+/**
+ * \brief Parse a string containing a list of key-value pairs
+ * \param[in] arguments The key-value pairs string to parse
+ *
+ * If a parsing error occurs, the parsing stops and the function returns an
+ * invalid container. The container is populated with the options successfully
+ * parsed so far.
+ *
+ * \return A valid container with the list of parsed options on success, or an
+ * invalid container otherwise
+ */
+KeyValueParser::Options KeyValueParser::parse(const char *arguments)
+{
+	Options options;
+
+	for (const char *pair = arguments; *arguments != '\0'; pair = arguments) {
+		const char *comma = strchrnul(arguments, ',');
+		size_t len = comma - pair;
+
+		/* Skip over the comma. */
+		arguments = *comma == ',' ? comma + 1 : comma;
+
+		/* Skip to the next pair if the pair is empty. */
+		if (!len)
+			continue;
+
+		std::string key;
+		std::string value;
+
+		const char *separator = static_cast<const char *>(memchr(pair, '=', len));
+		if (!separator) {
+			key = std::string(pair, len);
+			value = "";
+		} else {
+			key = std::string(pair, separator - pair);
+			value = std::string(separator + 1, comma - separator - 1);
+		}
+
+		/* The key is mandatory, the value might be optional. */
+		if (key.empty())
+			continue;
+
+		if (optionsMap_.find(key) == optionsMap_.end()) {
+			std::cerr << "Invalid option " << key << std::endl;
+			return options;
+		}
+
+		OptionArgument arg = optionsMap_[key].argument;
+		if (value.empty() && arg == ArgumentRequired) {
+			std::cerr << "Option " << key << " requires an argument"
+				  << std::endl;
+			return options;
+		} else if (!value.empty() && arg == ArgumentNone) {
+			std::cerr << "Option " << key << " takes no argument"
+				  << std::endl;
+			return options;
+		}
+
+		const Option &option = optionsMap_[key];
+		if (!options.parseValue(key, option, value.c_str())) {
+			std::cerr << "Failed to parse '" << value << "' as "
+				  << option.typeName() << " for option " << key
+				  << std::endl;
+			return options;
+		}
+	}
+
+	options.valid_ = true;
+	return options;
+}
+
+unsigned int KeyValueParser::maxOptionLength() const
+{
+	unsigned int maxLength = 0;
+
+	for (auto const &iter : optionsMap_) {
+		const Option &option = iter.second;
+		unsigned int length = 10 + strlen(option.name);
+		if (option.argument != ArgumentNone)
+			length += 1 + strlen(option.typeName());
+		if (option.argument == ArgumentOptional)
+			length += 2;
+
+		if (length > maxLength)
+			maxLength = length;
+	}
+
+	return maxLength;
+}
+
+void KeyValueParser::usage(int indent)
+{
+	for (auto const &iter : optionsMap_) {
+		const Option &option = iter.second;
+		std::string argument = std::string("          ") + option.name;
+
+		if (option.argument != ArgumentNone) {
+			if (option.argument == ArgumentOptional)
+				argument += "[=";
+			else
+				argument += "=";
+			argument += option.typeName();
+			if (option.argument == ArgumentOptional)
+				argument += "]";
+		}
+
+		std::cerr << std::setw(indent) << argument;
+
+		for (const char *help = option.help, *end = help; end;) {
+			end = strchr(help, '\n');
+			if (end) {
+				std::cerr << std::string(help, end - help + 1);
+				std::cerr << std::setw(indent) << " ";
+				help = end + 1;
+			} else {
+				std::cerr << help << std::endl;
+			}
+		}
+	}
+}
+
+/* -----------------------------------------------------------------------------
+ * OptionValue
+ */
+
+/**
+ * \class OptionValue
+ * \brief Container to store the value of an option
+ *
+ * The OptionValue class is a variant-type container to store the value of an
+ * option. It supports empty values, integers, strings, key-value lists, as well
+ * as arrays of those types. For array values, all array elements shall have the
+ * same type.
+ *
+ * OptionValue instances are organized in a tree-based structure that matches
+ * the parent-child relationship of the options added to the parser. Children
+ * are retrieved with the children() function, and are stored as an
+ * OptionsBase<int>.
+ */
+
+/**
+ * \enum OptionValue::ValueType
+ * \brief The option value type
+ *
+ * \var OptionValue::ValueType::ValueNone
+ * \brief Empty value
+ *
+ * \var OptionValue::ValueType::ValueInteger
+ * \brief Integer value (int)
+ *
+ * \var OptionValue::ValueType::ValueString
+ * \brief String value (std::string)
+ *
+ * \var OptionValue::ValueType::ValueKeyValue
+ * \brief Key-value list value (KeyValueParser::Options)
+ *
+ * \var OptionValue::ValueType::ValueArray
+ * \brief Array value
+ */
+
+/**
+ * \brief Construct an empty OptionValue instance
+ *
+ * The value type is set to ValueType::ValueNone.
+ */
+OptionValue::OptionValue()
+	: type_(ValueNone), integer_(0)
+{
+}
+
+/**
+ * \brief Construct an integer OptionValue instance
+ * \param[in] value The integer value
+ *
+ * The value type is set to ValueType::ValueInteger.
+ */
+OptionValue::OptionValue(int value)
+	: type_(ValueInteger), integer_(value)
+{
+}
+
+/**
+ * \brief Construct a string OptionValue instance
+ * \param[in] value The string value
+ *
+ * The value type is set to ValueType::ValueString.
+ */
+OptionValue::OptionValue(const char *value)
+	: type_(ValueString), integer_(0), string_(value)
+{
+}
+
+/**
+ * \brief Construct a string OptionValue instance
+ * \param[in] value The string value
+ *
+ * The value type is set to ValueType::ValueString.
+ */
+OptionValue::OptionValue(const std::string &value)
+	: type_(ValueString), integer_(0), string_(value)
+{
+}
+
+/**
+ * \brief Construct a key-value OptionValue instance
+ * \param[in] value The key-value list
+ *
+ * The value type is set to ValueType::ValueKeyValue.
+ */
+OptionValue::OptionValue(const KeyValueParser::Options &value)
+	: type_(ValueKeyValue), integer_(0), keyValues_(value)
+{
+}
+
+/**
+ * \brief Add an entry to an array value
+ * \param[in] value The entry value
+ *
+ * This function can only be called if the OptionValue type is
+ * ValueType::ValueNone or ValueType::ValueArray. Upon return, the type will be
+ * set to ValueType::ValueArray.
+ */
+void OptionValue::addValue(const OptionValue &value)
+{
+	assert(type_ == ValueNone || type_ == ValueArray);
+
+	type_ = ValueArray;
+	array_.push_back(value);
+}
+
+/**
+ * \fn OptionValue::type()
+ * \brief Retrieve the value type
+ * \return The value type
+ */
+
+/**
+ * \fn OptionValue::empty()
+ * \brief Check if the value is empty
+ * \return True if the value is empty (type set to ValueType::ValueNone), or
+ * false otherwise
+ */
+
+/**
+ * \brief Cast the value to an int
+ * \return The option value as an int, or 0 if the value type isn't
+ * ValueType::ValueInteger
+ */
+OptionValue::operator int() const
+{
+	return toInteger();
+}
+
+/**
+ * \brief Cast the value to a std::string
+ * \return The option value as an std::string, or an empty string if the value
+ * type isn't ValueType::ValueString
+ */
+OptionValue::operator std::string() const
+{
+	return toString();
+}
+
+/**
+ * \brief Retrieve the value as an int
+ * \return The option value as an int, or 0 if the value type isn't
+ * ValueType::ValueInteger
+ */
+int OptionValue::toInteger() const
+{
+	if (type_ != ValueInteger)
+		return 0;
+
+	return integer_;
+}
+
+/**
+ * \brief Retrieve the value as a std::string
+ * \return The option value as a std::string, or an empty string if the value
+ * type isn't ValueType::ValueString
+ */
+std::string OptionValue::toString() const
+{
+	if (type_ != ValueString)
+		return std::string();
+
+	return string_;
+}
+
+/**
+ * \brief Retrieve the value as a key-value list
+ *
+ * The behaviour is undefined if the value type isn't ValueType::ValueKeyValue.
+ *
+ * \return The option value as a KeyValueParser::Options
+ */
+const KeyValueParser::Options &OptionValue::toKeyValues() const
+{
+	assert(type_ == ValueKeyValue);
+	return keyValues_;
+}
+
+/**
+ * \brief Retrieve the value as an array
+ *
+ * The behaviour is undefined if the value type isn't ValueType::ValueArray.
+ *
+ * \return The option value as a std::vector of OptionValue
+ */
+const std::vector<OptionValue> &OptionValue::toArray() const
+{
+	assert(type_ == ValueArray);
+	return array_;
+}
+
+/**
+ * \brief Retrieve the list of child values
+ * \return The list of child values
+ */
+const OptionsParser::Options &OptionValue::children() const
+{
+	return children_;
+}
+
+/* -----------------------------------------------------------------------------
+ * OptionsParser
+ */
+
+/**
+ * \class OptionsParser
+ * \brief A command line options parser
+ *
+ * The OptionsParser class is an easy to use options parser for POSIX-style
+ * command line options. Supports short (e.g. `-f`) and long (e.g. `--foo`)
+ * options, optional and mandatory arguments, automatic parsing arguments for
+ * integer types and comma-separated list of key=value pairs, and multi-value
+ * arguments. It handles help text generation automatically.
+ *
+ * An OptionsParser instance is initialized by adding supported options with
+ * addOption(). Options are specified by an identifier and a name. If the
+ * identifier is an alphanumeric character, it will be used by the parser as a
+ * short option identifier (e.g. `-f`). The name, if specified, will be used as
+ * a long option identifier (e.g. `--foo`). It should not include the double
+ * dashes. The name is optional if the option identifier is an alphanumeric
+ * character and mandatory otherwise.
+ *
+ * An option has a mandatory help text, which is used to print the full options
+ * list with the usage() function. The help text may be a multi-line string.
+ * Correct indentation of the help text is handled automatically.
+ *
+ * Options accept arguments when created with OptionArgument::ArgumentRequired
+ * or OptionArgument::ArgumentOptional. If the argument is required, it can be
+ * specified as a positional argument after the option (e.g. `-f bar`,
+ * `--foo bar`), collated with the short option (e.g. `-fbar`) or separated from
+ * the long option by an equal sign (e.g. `--foo=bar`'). When the argument is
+ * optional, it must be collated with the short option or separated from the
+ * long option by an equal sign.
+ *
+ * If an option has a required or optional argument, an argument name must be
+ * set when adding the option. The argument name is used in the help text as a
+ * place holder for an argument value. For instance, a `--write` option that
+ * takes a file name as an argument could set the argument name to `filename`,
+ * and the help text would display `--write filename`. This is only used to
+ * clarify the help text and has no effect on option parsing.
+ *
+ * The option type tells the parser how to process the argument. Arguments for
+ * string options (OptionType::OptionString) are stored as-is without any
+ * processing. Arguments for integer options (OptionType::OptionInteger) are
+ * converted to an integer value, using an optional base prefix (`0` for base 8,
+ * `0x` for base 16, none for base 10). Arguments for key-value options are
+ * parsed by a KeyValueParser given to addOption().
+ *
+ * By default, a given option can appear once only in the parsed command line.
+ * If the option is created as an array option, the parser will accept multiple
+ * instances of the option. The order in which identical options are specified
+ * is preserved in the values of an array option.
+ *
+ * After preparing the parser, it can be used any number of times to parse
+ * command line options with the parse() function. The function returns an
+ * Options instance that stores the values for the parsed options. The
+ * Options::isSet() function can be used to test if an option has been found,
+ * and is the only way to access options that take no argument (specified by
+ * OptionType::OptionNone and OptionArgument::ArgumentNone). For options that
+ * accept an argument, the option value can be access by Options::operator[]()
+ * using the option identifier as the key. The order in which different options
+ * are specified on the command line isn't preserved.
+ *
+ * Options can be created with parent-child relationships to organize them as a
+ * tree instead of a flat list. When parsing a command line, the child options
+ * are considered related to the parent option that precedes them. This is
+ * useful when the parent is an array option. The Options values list generated
+ * by the parser then turns into a tree, which each parent value storing the
+ * values of child options that follow that instance of the parent option.
+ * For instance, with a `capture` option specified as a child of a `camera`
+ * array option, parsing the command line
+ *
+ * `--camera 1 --capture=10 --camera 2 --capture=20`
+ *
+ * will return an Options instance containing a single OptionValue instance of
+ * array type, for the `camera` option. The OptionValue will contain two
+ * entries, with the first entry containing the integer value 1 and the second
+ * entry the integer value 2. Each of those entries will in turn store an
+ * Options instance that contains the respective children. The first entry will
+ * store in its children a `capture` option of value 10, and the second entry a
+ * `capture` option of value 20.
+ *
+ * The command line
+ *
+ * `--capture=10 --camera 1`
+ *
+ * would result in a parsing error, as the `capture` option has no preceding
+ * `camera` option on the command line.
+ */
+
+/**
+ * \class OptionsParser::Options
+ * \brief An option list generated by the options parser
+ *
+ * This is a specialization of OptionsBase with the option reference type set to
+ * int.
+ */
+
+OptionsParser::OptionsParser() = default;
+OptionsParser::~OptionsParser() = default;
+
+/**
+ * \brief Add an option to the parser
+ * \param[in] opt The option identifier
+ * \param[in] type The type of the option argument
+ * \param[in] help The help text (may be a multi-line string)
+ * \param[in] name The option name
+ * \param[in] argument Whether the option accepts an optional argument, a
+ * mandatory argument, or no argument at all
+ * \param[in] argumentName The argument name used in the help text
+ * \param[in] array Whether the option can appear once or multiple times
+ * \param[in] parent The identifier of the parent option (optional)
+ *
+ * \return True if the option was added successfully, false if an error
+ * occurred.
+ */
+bool OptionsParser::addOption(int opt, OptionType type, const char *help,
+			      const char *name, OptionArgument argument,
+			      const char *argumentName, bool array, int parent)
+{
+	/*
+	 * 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 false;
+	if (!help || help[0] == '\0')
+		return false;
+	if (argument != ArgumentNone && !argumentName)
+		return false;
+
+	/* Reject duplicate options. */
+	if (optionsMap_.find(opt) != optionsMap_.end())
+		return false;
+
+	/*
+	 * If a parent is specified, create the option as a child of its parent.
+	 * Otherwise, create it in the parser's options list.
+	 */
+	Option *option;
+
+	if (parent) {
+		auto iter = optionsMap_.find(parent);
+		if (iter == optionsMap_.end())
+			return false;
+
+		Option *parentOpt = iter->second;
+		parentOpt->children.push_back({
+			opt, type, name, argument, argumentName, help, nullptr,
+			array, parentOpt, {}
+		});
+		option = &parentOpt->children.back();
+	} else {
+		options_.push_back({ opt, type, name, argument, argumentName,
+				     help, nullptr, array, nullptr, {} });
+		option = &options_.back();
+	}
+
+	optionsMap_[opt] = option;
+
+	return true;
+}
+
+/**
+ * \brief Add a key-value pair option to the parser
+ * \param[in] opt The option identifier
+ * \param[in] parser The KeyValueParser for the option value
+ * \param[in] help The help text (may be a multi-line string)
+ * \param[in] name The option name
+ * \param[in] array Whether the option can appear once or multiple times
+ *
+ * \sa Option
+ *
+ * \return True if the option was added successfully, false if an error
+ * occurred.
+ */
+bool OptionsParser::addOption(int opt, KeyValueParser *parser, const char *help,
+			      const char *name, bool array, int parent)
+{
+	if (!addOption(opt, OptionKeyValue, help, name, ArgumentRequired,
+		       "key=value[,key=value,...]", array, parent))
+		return false;
+
+	optionsMap_[opt]->keyValueParser = parser;
+	return true;
+}
+
+/**
+ * \brief Parse command line arguments
+ * \param[in] argc The number of arguments in the \a argv array
+ * \param[in] argv The array of arguments
+ *
+ * If a parsing error occurs, the parsing stops, the function prints an error
+ * message that identifies the invalid argument, prints usage information with
+ * usage(), and returns an invalid container. The container is populated with
+ * the options successfully parsed so far.
+ *
+ * \return A valid container with the list of parsed options on success, or an
+ * invalid container otherwise
+ */
+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[optionsMap_.size() * 3 + 2];
+	struct option longOptions[optionsMap_.size() + 1];
+	unsigned int ids = 0;
+	unsigned int idl = 0;
+
+	shortOptions[ids++] = ':';
+
+	for (const auto [opt, option] : optionsMap_) {
+		if (option->hasShortOption()) {
+			shortOptions[ids++] = 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++;
+		}
+	}
+
+	shortOptions[ids] = '\0';
+	memset(&longOptions[idl], 0, sizeof(longOptions[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();
+			return options;
+		}
+
+		const Option &option = *optionsMap_[c];
+		if (!parseValue(option, optarg, &options)) {
+			usage();
+			return options;
+		}
+	}
+
+	if (optind < argc) {
+		std::cerr << "Invalid non-option argument '" << argv[optind]
+			  << "'" << std::endl;
+		usage();
+		return options;
+	}
+
+	options.valid_ = true;
+	return options;
+}
+
+/**
+ * \brief Print usage text to std::cerr
+ *
+ * The usage text list all the supported option with their arguments. It is
+ * generated automatically from the options added to the parser. Caller of this
+ * function may print additional usage information for the application before
+ * the list of options.
+ */
+void OptionsParser::usage()
+{
+	unsigned int indent = 0;
+
+	for (const auto &opt : optionsMap_) {
+		const Option *option = opt.second;
+		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 (option->isArray)
+			length += 4;
+
+		if (length > indent)
+			indent = length;
+
+		if (option->keyValueParser) {
+			length = option->keyValueParser->maxOptionLength();
+			if (length > indent)
+				indent = length;
+		}
+	}
+
+	indent = (indent + 7) / 8 * 8;
+
+	std::cerr << "Options:" << std::endl;
+
+	std::ios_base::fmtflags f(std::cerr.flags());
+	std::cerr << std::left;
+
+	usageOptions(options_, indent);
+
+	std::cerr.flags(f);
+}
+
+void OptionsParser::usageOptions(const std::list<Option> &options,
+				 unsigned int indent)
+{
+	std::vector<const Option *> parentOptions;
+
+	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) {
+			if (option.argument == ArgumentOptional)
+				argument += "[=";
+			else
+				argument += " ";
+			argument += option.argumentName;
+			if (option.argument == ArgumentOptional)
+				argument += "]";
+		}
+
+		if (option.isArray)
+			argument += " ...";
+
+		std::cerr << std::setw(indent) << argument;
+
+		for (const char *help = option.help, *end = help; end; ) {
+			end = strchr(help, '\n');
+			if (end) {
+				std::cerr << std::string(help, end - help + 1);
+				std::cerr << std::setw(indent) << " ";
+				help = end + 1;
+			} else {
+				std::cerr << help << std::endl;
+			}
+		}
+
+		if (option.keyValueParser)
+			option.keyValueParser->usage(indent);
+
+		if (!option.children.empty())
+			parentOptions.push_back(&option);
+	}
+
+	if (parentOptions.empty())
+		return;
+
+	for (const Option *option : parentOptions) {
+		std::cerr << std::endl << "Options valid in the context of "
+			  << option->optionName() << ":" << std::endl;
+		usageOptions(option->children, indent);
+	}
+}
+
+std::tuple<OptionsParser::Options *, const Option *>
+OptionsParser::childOption(const Option *parent, Options *options)
+{
+	/*
+	 * The parent argument points to the parent of the leaf node Option,
+	 * and the options argument to the root node of the Options tree. Use
+	 * recursive calls to traverse the Option tree up to the root node while
+	 * traversing the Options tree down to the leaf node:
+	 */
+
+	/*
+	 * - If we have no parent, we've reached the root node of the Option
+	 *   tree, the options argument is what we need.
+	 */
+	if (!parent)
+		return { options, nullptr };
+
+	/*
+	 * - If the parent has a parent, use recursion to move one level up the
+	 *   Option tree. This returns the Options corresponding to parent, or
+	 *   nullptr if a suitable Options child isn't found.
+	 */
+	if (parent->parent) {
+		const Option *error;
+		std::tie(options, error) = childOption(parent->parent, options);
+
+		/* Propagate the error all the way back up the call stack. */
+		if (!error)
+			return { options, error };
+	}
+
+	/*
+	 * - The parent has no parent, we're now one level down the root.
+	 *   Return the Options child corresponding to the parent. The child may
+	 *   not exist if options are specified in an incorrect order.
+	 */
+	if (!options->isSet(parent->opt))
+		return { nullptr, parent };
+
+	/*
+	 * If the child value is of array type, children are not stored in the
+	 * value .children() list, but in the .children() of the value's array
+	 * elements. Use the last array element in that case, as a child option
+	 * relates to the last instance of its parent option.
+	 */
+	const OptionValue *value = &(*options)[parent->opt];
+	if (value->type() == OptionValue::ValueArray)
+		value = &value->toArray().back();
+
+	return { const_cast<Options *>(&value->children()), nullptr };
+}
+
+bool OptionsParser::parseValue(const Option &option, const char *arg,
+			       Options *options)
+{
+	const Option *error;
+
+	std::tie(options, error) = childOption(option.parent, options);
+	if (error) {
+		std::cerr << "Option " << option.optionName() << " requires a "
+			  << error->optionName() << " context" << std::endl;
+		return false;
+	}
+
+	if (!options->parseValue(option.opt, option, arg)) {
+		std::cerr << "Can't parse " << option.typeName()
+			  << " argument for option " << option.optionName()
+			  << std::endl;
+		return false;
+	}
+
+	return true;
+}
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