GNXSOFT.COM

gnx-react/venv/lib/python3.12/site-packages/vine/synchronization.py

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+"""Synchronization primitives."""
+from .abstract import Thenable
+from .promises import promise
+
+__all__ = ['barrier']
+
+
+class barrier:
+    """Barrier.
+
+    Synchronization primitive to call a callback after a list
+    of promises have been fulfilled.
+
+    Example:
+
+    .. code-block:: python
+
+        # Request supports the .then() method.
+        p1 = http.Request('http://a')
+        p2 = http.Request('http://b')
+        p3 = http.Request('http://c')
+        requests = [p1, p2, p3]
+
+        def all_done():
+            pass  # all requests complete
+
+        b = barrier(requests).then(all_done)
+
+        # oops, we forgot we want another request
+        b.add(http.Request('http://d'))
+
+    Note that you cannot add new promises to a barrier after
+    the barrier is fulfilled.
+    """
+
+    def __init__(self, promises=None, args=None, kwargs=None,
+                 callback=None, size=None):
+        self.p = promise()
+        self.args = args or ()
+        self.kwargs = kwargs or {}
+        self._value = 0
+        self.size = size or 0
+        if not self.size and promises:
+            # iter(l) calls len(l) so generator wrappers
+            # can only return NotImplemented in the case the
+            # generator is not fully consumed yet.
+            plen = promises.__len__()
+            if plen is not NotImplemented:
+                self.size = plen
+        self.ready = self.failed = False
+        self.reason = None
+        self.cancelled = False
+        self.finalized = False
+
+        [self.add_noincr(p) for p in promises or []]
+        self.finalized = bool(promises or self.size)
+        if callback:
+            self.then(callback)
+
+        __slots__ = (  # noqa
+            'p', 'args', 'kwargs', '_value', 'size',
+            'ready', 'reason', 'cancelled', 'finalized',
+            '__weakref__',
+            # adding '__dict__' to get dynamic assignment
+            "__dict__",
+        )
+
+    def __call__(self, *args, **kwargs):
+        if not self.ready and not self.cancelled:
+            self._value += 1
+            if self.finalized and self._value >= self.size:
+                self.ready = True
+                self.p(*self.args, **self.kwargs)
+
+    def finalize(self):
+        if not self.finalized and self._value >= self.size:
+            self.p(*self.args, **self.kwargs)
+        self.finalized = True
+
+    def cancel(self):
+        self.cancelled = True
+        self.p.cancel()
+
+    def add_noincr(self, p):
+        if not self.cancelled:
+            if self.ready:
+                raise ValueError('Cannot add promise to full barrier')
+            p.then(self)
+
+    def add(self, p):
+        if not self.cancelled:
+            self.add_noincr(p)
+            self.size += 1
+
+    def then(self, callback, errback=None):
+        self.p.then(callback, errback)
+
+    def throw(self, *args, **kwargs):
+        if not self.cancelled:
+            self.p.throw(*args, **kwargs)
+    throw1 = throw
+
+
+Thenable.register(barrier)