mm::core Namespace Reference

Classes
class	CyclicTimer
	Precision cyclic timer for fixed-period loops. More...
class	SingleInstanceLock
	RAII holder of the process-wide single-instance lock. More...
struct	SystemInfo

Functions
std::filesystem::path	exeDir ()
	Return the directory that contains the running executable.
void	openInBrowser (const std::string &url)
	Open the given URL in the system default browser.
std::expected< SingleInstanceLock, std::string >	acquireSingleInstanceLock ()
	Acquire the process-wide lock that permits only one running Motion Master.
SystemInfo	collectSystemInfo ()
void	to_json (nlohmann::json &j, const SystemInfo &info)
bool	isUrlSafeId (std::string_view s)
	Whether s is a valid URL-safe identifier usable as a path segment and pub/sub topic.
template<typename T >
std::optional< T >	parseHexOrDec (std::string_view s)
	Parses an unsigned integer from a string in decimal or hexadecimal notation.
template<typename T >
std::array< uint8_t, sizeof(T)>	toBytes (T value, std::endian order=std::endian::little)
	Encodes an integer into a fixed-width byte array in the given byte order.
template<typename T >
T	fromBytes (std::span< const uint8_t > bytes, std::endian order=std::endian::little)
	Decodes an integer from a raw byte buffer interpreted in the given byte order.

Function Documentation

acquireSingleInstanceLock()

std::expected< SingleInstanceLock, std::string > mm::core::acquireSingleInstanceLock

(

)

Acquire the process-wide lock that permits only one running Motion Master.

Non-blocking. Returns the held lock when no other instance holds it; fails when one already does. The lock guards the whole process — acquired before the EtherCAT NIC is claimed and before the servers bind — so a second master can never drive the same bus alongside the first. The exclusive port bind is only a backstop: it fires too late (the NIC is already claimed by then) and misses instances configured on different ports, so the lock, not the port, is the real guard.

• Linux/macOS: flock(LOCK_EX|LOCK_NB) on <temp_dir>/motion-master.lock (machine-wide).
• Windows: a named mutex in the session-local namespace (per interactive session — a standard user cannot create objects in the machine-global namespace).

  Returns

  The held lock on success; an error string describing the conflict on failure.

collectSystemInfo()

SystemInfo mm::core::collectSystemInfo

(

)

exeDir()

std::filesystem::path mm::core::exeDir

(

)

Return the directory that contains the running executable.

argv[0] is not used — it can be a relative path, a bare command name resolved via PATH, or a symlink.

Platform behaviour

• Linux: resolves /proc/self/exe via std::filesystem::canonical.
• macOS: queries the path via _NSGetExecutablePath (no /proc).
• Windows: queries the path via GetModuleFileNameW.

  Returns

  Absolute path to the executable's parent directory.

fromBytes()

template<typename T >

T mm::core::fromBytes	(	std::span< const uint8_t >	bytes,
		std::endian	order = std::endian::little
	)

Decodes an integer from a raw byte buffer interpreted in the given byte order.

Reads up to sizeof(T) bytes. A short buffer is treated as if zero-padded (the missing most-significant bytes read as zero) — defensive against a slave returning fewer bytes than the type implies; excess bytes are ignored. Accumulation is done in the unsigned representation so the shift is well-defined for signed T. Defaults to little-endian (EtherCAT/CoE wire order).

Template Parameters

T	Integral result type whose size fixes how many bytes are consumed.

Parameters

bytes	Source buffer (a std::vector<uint8_t> binds implicitly).
order	Byte order to interpret bytes in (default little-endian).

Returns

The decoded value.

isUrlSafeId()

bool mm::core::isUrlSafeId ( std::string_view  s )

inline

Whether s is a valid URL-safe identifier usable as a path segment and pub/sub topic.

Accepts a non-empty string of at most 64 characters drawn from [A-Za-z0-9._-] — the unreserved subset that needs no percent-encoding in a URL path segment and carries no special meaning to the uWebSockets topic parser. Rejecting '/' is doubly load-bearing: the id is a single REST path segment (e.g. GET /api/monitorings/{topic}), so a '/' would spill into extra segments and miss the route; and uWebSockets treats it as a topic hierarchy delimiter. Comparison is case-sensitive, so "Motor" and "motor" are distinct identifiers.

Parameters

s	Candidate identifier.

Returns

true if every character is allowed and the length is in [1, 64].

openInBrowser()

void mm::core::openInBrowser

(

const std::string &

url

)

Open the given URL in the system default browser.

Non-blocking — returns immediately after spawning the browser process. Uses xdg-open on Linux, open on macOS, and ShellExecute on Windows.

Parameters

url	URL to open.

parseHexOrDec()

template<typename T >

std::optional< T > mm::core::parseHexOrDec

(

std::string_view

s

)

Parses an unsigned integer from a string in decimal or hexadecimal notation.

Accepts a 0x / 0X prefix (C-style) or a #x / #X prefix (as EtherCAT ESI/XML files write hex constants, e.g. "#x00000201") to select hexadecimal; any other input is parsed as decimal. Trailing characters and out-of-range values are rejected.

Template Parameters

T	Unsigned integer type to parse into (e.g. uint16_t, uint8_t).

Parameters

s	Input string view.

Returns

The parsed value on success, or std::nullopt if s is not a valid decimal or hexadecimal representation of a T value.

to_json()

void mm::core::to_json	(	nlohmann::json &	j,
		const SystemInfo &	info
	)

toBytes()

template<typename T >

std::array< uint8_t, sizeof(T)> mm::core::toBytes	(	T	value,
		std::endian	order = std::endian::little
	)

Encodes an integer into a fixed-width byte array in the given byte order.

The width is sizeof(T), so toBytes<uint8_t> yields one byte, uint16_t two, and so on. Signed values are encoded through their unsigned representation (two's complement), so the shift is always well-defined. Defaults to little-endian (EtherCAT/CoE wire order); pass std::endian::big for the reverse. The returned array is the natural argument for a byte-span sink such as FieldbusDriver::writeSdo — a temporary result lives to the end of the enclosing call.

Template Parameters

T	Integral type whose size fixes the byte count.

Parameters

value	Value to encode.
order	Byte order of the output (default little-endian).

Returns

A std::array of sizeof(T) bytes in order.