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|
/* 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;
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