jyoung/common/params_pyx.pyx

# distutils: language = c++
# cython: language_level = 3
from libcpp cimport bool
from libcpp.string cimport string
import threading

cdef extern from "selfdrive/common/params.h":
  cpdef enum ParamKeyType:
    PERSISTENT
    CLEAR_ON_MANAGER_START
    CLEAR_ON_PANDA_DISCONNECT
    CLEAR_ON_IGNITION_ON
    CLEAR_ON_IGNITION_OFF
    ALL

  cdef cppclass c_Params "Params":
    c_Params(string) nogil
    string get(string, bool) nogil
    bool getBool(string) nogil
    int remove(string) nogil
    int put(string, string) nogil
    int putBool(string, bool) nogil
    bool checkKey(string) nogil
    void clearAll(ParamKeyType)


def ensure_bytes(v):
  return v.encode() if isinstance(v, str) else v;

class UnknownKeyName(Exception):
  pass

cdef class Params:
  cdef c_Params* p

  def __cinit__(self, d=""):
    cdef string path = <string>d.encode()
    with nogil:
      self.p = new c_Params(path)

  def __dealloc__(self):
    del self.p

  def clear_all(self, tx_type=ParamKeyType.ALL):
    self.p.clearAll(tx_type)

  def check_key(self, key):
    key = ensure_bytes(key)
    if not self.p.checkKey(key):
      raise UnknownKeyName(key)
    return key

  def get(self, key, bool block=False, encoding=None):
    cdef string k = self.check_key(key)
    cdef string val
    with nogil:
      val = self.p.get(k, block)

    if val == b"":
      if block:
        # If we got no value while running in blocked mode
        # it means we got an interrupt while waiting
        raise KeyboardInterrupt
      else:
        return None

    return val if encoding is None else val.decode(encoding)

  def get_bool(self, key):
    cdef string k = self.check_key(key)
    cdef bool r
    with nogil:
      r = self.p.getBool(k)
    return r

  def put(self, key, dat):
    """
    Warning: This function blocks until the param is written to disk!
    In very rare cases this can take over a second, and your code will hang.
    Use the put_nonblocking helper function in time sensitive code, but
    in general try to avoid writing params as much as possible.
    """
    cdef string k = self.check_key(key)
    cdef string dat_bytes = ensure_bytes(dat)
    with nogil:
      self.p.put(k, dat_bytes)

  def put_bool(self, key, bool val):
    cdef string k = self.check_key(key)
    with nogil:
      self.p.putBool(k, val)

  def delete(self, key):
    cdef string k = self.check_key(key)
    with nogil:
      self.p.remove(k)

def put_nonblocking(key, val, d=""):
  def f(key, val):
    params = Params(d)
    cdef string k = ensure_bytes(key)
    params.put(k, val)

  t = threading.Thread(target=f, args=(key, val))
  t.start()
  return t