feat: speed up processing incoming records (#1216)

src/zeroconf/_dns.pxd

@@ -44,6 +44,8 @@ cdef class DNSRecord(DNSEntry):
     )
     cpdef suppressed_by(self, object msg)
 
+    cpdef get_remaining_ttl(self, cython.float now)
+
     cpdef get_expiration_time(self, cython.uint percent)
 
     cpdef is_expired(self, cython.float now)
@@ -54,6 +56,8 @@ cdef class DNSRecord(DNSEntry):
 
     cpdef reset_ttl(self, DNSRecord other)
 
+    cpdef set_created_ttl(self, cython.float now, cython.float ttl)
+
 cdef class DNSAddress(DNSRecord):
 
     cdef public cython.int _hash

src/zeroconf/_dns.py

@@ -26,7 +26,7 @@
 
 from ._exceptions import AbstractMethodException
 from ._utils.net import _is_v6_address
-from ._utils.time import current_time_millis, millis_to_seconds
+from ._utils.time import current_time_millis
 from .const import _CLASS_MASK, _CLASS_UNIQUE, _CLASSES, _TYPE_ANY, _TYPES
 
 _LEN_BYTE = 1
@@ -193,7 +193,8 @@ def get_expiration_time(self, percent: _int) -> float:
     # TODO: Switch to just int here
     def get_remaining_ttl(self, now: _float) -> Union[int, float]:
         """Returns the remaining TTL in seconds."""
-        return max(0, millis_to_seconds((self.created + (_EXPIRE_FULL_TIME_MS * self.ttl)) - now))
+        remain = (self.created + (_EXPIRE_FULL_TIME_MS * self.ttl) - now) / 1000.0
+        return 0 if remain < 0 else remain
 
     def is_expired(self, now: _float) -> bool:
         """Returns true if this record has expired."""
@@ -212,7 +213,7 @@ def reset_ttl(self, other) -> None:  # type: ignore[no-untyped-def]
         another record."""
         self.set_created_ttl(other.created, other.ttl)
 
-    def set_created_ttl(self, created: float, ttl: Union[float, int]) -> None:
+    def set_created_ttl(self, created: _float, ttl: Union[float, int]) -> None:
         """Set the created and ttl of a record."""
         self.created = created
         self.ttl = ttl

src/zeroconf/_handlers.py

@@ -408,6 +408,7 @@ def async_updates_from_response(self, msg: DNSIncoming) -> None:
         removes: Set[DNSRecord] = set()
         now = msg.now
         unique_types: Set[Tuple[str, int, int]] = set()
+        cache = self.cache
 
         for record in msg.answers:
             # Protect zeroconf from records that can cause denial of service.
@@ -416,7 +417,9 @@ def async_updates_from_response(self, msg: DNSIncoming) -> None:
             # ServiceBrowsers generating excessive queries refresh queries.
             # Apple uses a 15s minimum TTL, however we do not have the same
             # level of rate limit and safe guards so we use 1/4 of the recommended value.
-            if record.ttl and record.type == _TYPE_PTR and record.ttl < _DNS_PTR_MIN_TTL:
+            record_type = record.type
+            record_ttl = record.ttl
+            if record_ttl and record_type == _TYPE_PTR and record_ttl < _DNS_PTR_MIN_TTL:
                 log.debug(
                     "Increasing effective ttl of %s to minimum of %s to protect against excessive refreshes.",
                     record,
@@ -425,12 +428,12 @@ def async_updates_from_response(self, msg: DNSIncoming) -> None:
                 record.set_created_ttl(record.created, _DNS_PTR_MIN_TTL)
 
             if record.unique:  # https://tools.ietf.org/html/rfc6762#section-10.2
-                unique_types.add((record.name, record.type, record.class_))
+                unique_types.add((record.name, record_type, record.class_))
 
             if TYPE_CHECKING:
                 record = cast(_UniqueRecordsType, record)
 
-            maybe_entry = self.cache.async_get_unique(record)
+            maybe_entry = cache.async_get_unique(record)
             if not record.is_expired(now):
                 if maybe_entry is not None:
                     maybe_entry.reset_ttl(record)
@@ -447,7 +450,7 @@ def async_updates_from_response(self, msg: DNSIncoming) -> None:
                 removes.add(record)
 
         if unique_types:
-            self.cache.async_mark_unique_records_older_than_1s_to_expire(unique_types, msg.answers, now)
+            cache.async_mark_unique_records_older_than_1s_to_expire(unique_types, msg.answers, now)
 
         if updates:
             self.async_updates(now, updates)
@@ -468,12 +471,12 @@ def async_updates_from_response(self, msg: DNSIncoming) -> None:
         # processsed.
         new = False
         if other_adds or address_adds:
-            new = self.cache.async_add_records(itertools.chain(address_adds, other_adds))
+            new = cache.async_add_records(itertools.chain(address_adds, other_adds))
         # Removes are processed last since
         # ServiceInfo could generate an un-needed query
         # because the data was not yet populated.
         if removes:
-            self.cache.async_remove_records(removes)
+            cache.async_remove_records(removes)
         if updates:
             self.async_updates_complete(new)