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stbi/Lib/site-packages/pip/_vendor/retrying.py

+## Copyright 2013-2014 Ray Holder
+##
+## Licensed under the Apache License, Version 2.0 (the "License");
+## you may not use this file except in compliance with the License.
+## You may obtain a copy of the License at
+##
+## http://www.apache.org/licenses/LICENSE-2.0
+##
+## Unless required by applicable law or agreed to in writing, software
+## distributed under the License is distributed on an "AS IS" BASIS,
+## WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+## See the License for the specific language governing permissions and
+## limitations under the License.
+
+import random
+from pip._vendor import six
+import sys
+import time
+import traceback
+
+
+# sys.maxint / 2, since Python 3.2 doesn't have a sys.maxint...
+MAX_WAIT = 1073741823
+
+
+def retry(*dargs, **dkw):
+    """
+    Decorator function that instantiates the Retrying object
+    @param *dargs: positional arguments passed to Retrying object
+    @param **dkw: keyword arguments passed to the Retrying object
+    """
+    # support both @retry and @retry() as valid syntax
+    if len(dargs) == 1 and callable(dargs[0]):
+        def wrap_simple(f):
+
+            @six.wraps(f)
+            def wrapped_f(*args, **kw):
+                return Retrying().call(f, *args, **kw)
+
+            return wrapped_f
+
+        return wrap_simple(dargs[0])
+
+    else:
+        def wrap(f):
+
+            @six.wraps(f)
+            def wrapped_f(*args, **kw):
+                return Retrying(*dargs, **dkw).call(f, *args, **kw)
+
+            return wrapped_f
+
+        return wrap
+
+
+class Retrying(object):
+
+    def __init__(self,
+                 stop=None, wait=None,
+                 stop_max_attempt_number=None,
+                 stop_max_delay=None,
+                 wait_fixed=None,
+                 wait_random_min=None, wait_random_max=None,
+                 wait_incrementing_start=None, wait_incrementing_increment=None,
+                 wait_exponential_multiplier=None, wait_exponential_max=None,
+                 retry_on_exception=None,
+                 retry_on_result=None,
+                 wrap_exception=False,
+                 stop_func=None,
+                 wait_func=None,
+                 wait_jitter_max=None):
+
+        self._stop_max_attempt_number = 5 if stop_max_attempt_number is None else stop_max_attempt_number
+        self._stop_max_delay = 100 if stop_max_delay is None else stop_max_delay
+        self._wait_fixed = 1000 if wait_fixed is None else wait_fixed
+        self._wait_random_min = 0 if wait_random_min is None else wait_random_min
+        self._wait_random_max = 1000 if wait_random_max is None else wait_random_max
+        self._wait_incrementing_start = 0 if wait_incrementing_start is None else wait_incrementing_start
+        self._wait_incrementing_increment = 100 if wait_incrementing_increment is None else wait_incrementing_increment
+        self._wait_exponential_multiplier = 1 if wait_exponential_multiplier is None else wait_exponential_multiplier
+        self._wait_exponential_max = MAX_WAIT if wait_exponential_max is None else wait_exponential_max
+        self._wait_jitter_max = 0 if wait_jitter_max is None else wait_jitter_max
+
+        # TODO add chaining of stop behaviors
+        # stop behavior
+        stop_funcs = []
+        if stop_max_attempt_number is not None:
+            stop_funcs.append(self.stop_after_attempt)
+
+        if stop_max_delay is not None:
+            stop_funcs.append(self.stop_after_delay)
+
+        if stop_func is not None:
+            self.stop = stop_func
+
+        elif stop is None:
+            self.stop = lambda attempts, delay: any(f(attempts, delay) for f in stop_funcs)
+
+        else:
+            self.stop = getattr(self, stop)
+
+        # TODO add chaining of wait behaviors
+        # wait behavior
+        wait_funcs = [lambda *args, **kwargs: 0]
+        if wait_fixed is not None:
+            wait_funcs.append(self.fixed_sleep)
+
+        if wait_random_min is not None or wait_random_max is not None:
+            wait_funcs.append(self.random_sleep)
+
+        if wait_incrementing_start is not None or wait_incrementing_increment is not None:
+            wait_funcs.append(self.incrementing_sleep)
+
+        if wait_exponential_multiplier is not None or wait_exponential_max is not None:
+            wait_funcs.append(self.exponential_sleep)
+
+        if wait_func is not None:
+            self.wait = wait_func
+
+        elif wait is None:
+            self.wait = lambda attempts, delay: max(f(attempts, delay) for f in wait_funcs)
+
+        else:
+            self.wait = getattr(self, wait)
+
+        # retry on exception filter
+        if retry_on_exception is None:
+            self._retry_on_exception = self.always_reject
+        else:
+            self._retry_on_exception = retry_on_exception
+
+        # TODO simplify retrying by Exception types
+        # retry on result filter
+        if retry_on_result is None:
+            self._retry_on_result = self.never_reject
+        else:
+            self._retry_on_result = retry_on_result
+
+        self._wrap_exception = wrap_exception
+
+    def stop_after_attempt(self, previous_attempt_number, delay_since_first_attempt_ms):
+        """Stop after the previous attempt >= stop_max_attempt_number."""
+        return previous_attempt_number >= self._stop_max_attempt_number
+
+    def stop_after_delay(self, previous_attempt_number, delay_since_first_attempt_ms):
+        """Stop after the time from the first attempt >= stop_max_delay."""
+        return delay_since_first_attempt_ms >= self._stop_max_delay
+
+    def no_sleep(self, previous_attempt_number, delay_since_first_attempt_ms):
+        """Don't sleep at all before retrying."""
+        return 0
+
+    def fixed_sleep(self, previous_attempt_number, delay_since_first_attempt_ms):
+        """Sleep a fixed amount of time between each retry."""
+        return self._wait_fixed
+
+    def random_sleep(self, previous_attempt_number, delay_since_first_attempt_ms):
+        """Sleep a random amount of time between wait_random_min and wait_random_max"""
+        return random.randint(self._wait_random_min, self._wait_random_max)
+
+    def incrementing_sleep(self, previous_attempt_number, delay_since_first_attempt_ms):
+        """
+        Sleep an incremental amount of time after each attempt, starting at
+        wait_incrementing_start and incrementing by wait_incrementing_increment
+        """
+        result = self._wait_incrementing_start + (self._wait_incrementing_increment * (previous_attempt_number - 1))
+        if result < 0:
+            result = 0
+        return result
+
+    def exponential_sleep(self, previous_attempt_number, delay_since_first_attempt_ms):
+        exp = 2 ** previous_attempt_number
+        result = self._wait_exponential_multiplier * exp
+        if result > self._wait_exponential_max:
+            result = self._wait_exponential_max
+        if result < 0:
+            result = 0
+        return result
+
+    def never_reject(self, result):
+        return False
+
+    def always_reject(self, result):
+        return True
+
+    def should_reject(self, attempt):
+        reject = False
+        if attempt.has_exception:
+            reject |= self._retry_on_exception(attempt.value[1])
+        else:
+            reject |= self._retry_on_result(attempt.value)
+
+        return reject
+
+    def call(self, fn, *args, **kwargs):
+        start_time = int(round(time.time() * 1000))
+        attempt_number = 1
+        while True:
+            try:
+                attempt = Attempt(fn(*args, **kwargs), attempt_number, False)
+            except:
+                tb = sys.exc_info()
+                attempt = Attempt(tb, attempt_number, True)
+
+            if not self.should_reject(attempt):
+                return attempt.get(self._wrap_exception)
+
+            delay_since_first_attempt_ms = int(round(time.time() * 1000)) - start_time
+            if self.stop(attempt_number, delay_since_first_attempt_ms):
+                if not self._wrap_exception and attempt.has_exception:
+                    # get() on an attempt with an exception should cause it to be raised, but raise just in case
+                    raise attempt.get()
+                else:
+                    raise RetryError(attempt)
+            else:
+                sleep = self.wait(attempt_number, delay_since_first_attempt_ms)
+                if self._wait_jitter_max:
+                    jitter = random.random() * self._wait_jitter_max
+                    sleep = sleep + max(0, jitter)
+                time.sleep(sleep / 1000.0)
+
+            attempt_number += 1
+
+
+class Attempt(object):
+    """
+    An Attempt encapsulates a call to a target function that may end as a
+    normal return value from the function or an Exception depending on what
+    occurred during the execution.
+    """
+
+    def __init__(self, value, attempt_number, has_exception):
+        self.value = value
+        self.attempt_number = attempt_number
+        self.has_exception = has_exception
+
+    def get(self, wrap_exception=False):
+        """
+        Return the return value of this Attempt instance or raise an Exception.
+        If wrap_exception is true, this Attempt is wrapped inside of a
+        RetryError before being raised.
+        """
+        if self.has_exception:
+            if wrap_exception:
+                raise RetryError(self)
+            else:
+                six.reraise(self.value[0], self.value[1], self.value[2])
+        else:
+            return self.value
+
+    def __repr__(self):
+        if self.has_exception:
+            return "Attempts: {0}, Error:\n{1}".format(self.attempt_number, "".join(traceback.format_tb(self.value[2])))
+        else:
+            return "Attempts: {0}, Value: {1}".format(self.attempt_number, self.value)
+
+
+class RetryError(Exception):
+    """
+    A RetryError encapsulates the last Attempt instance right before giving up.
+    """
+
+    def __init__(self, last_attempt):
+        self.last_attempt = last_attempt
+
+    def __str__(self):
+        return "RetryError[{0}]".format(self.last_attempt)