From 2702638eabe5f7b25f36d295f0ad78cb8d4eda05 Mon Sep 17 00:00:00 2001 From: Michael Selik Date: Thu, 19 Sep 2019 20:25:55 -0700 Subject: bpo-34002: Minor efficiency and clarity improvements in email package. (GH-7999) * Check intersection of two sets explicitly Comparing ``len(a) > ``len(a - b)`` is essentially looking for an intersection between the two sets. If set ``b`` does not intersect ``a`` then ``len(a - b)`` will be equal to ``len(a)``. This logic is more clearly expressed as ``a & b``. * Change while/pop to a for-loop Copying the list, then repeatedly popping the first element was unnecessarily slow. I also cleaned up a couple other inefficiencies. There's no need to unpack a tuple, then re-pack and append it. The list can be created with the first element instead of empty. Secondly, the ``endswith`` method returns a bool, so there's no need for an if- statement to set ``encoding`` to True or False. * Use set.intersection to check for intersections ``a.intersection(b)`` method is more clear of purpose than ``not a.isdisjoint(b)`` and avoids an unnecessary set construction that ``a & set(b)`` performs. * Use not isdisjoint instead of intersection While it reads slightly worse, the isdisjoint method will stop when it finds a counterexample and returns a bool, rather than looping over the entire iterable and constructing a new set. --- Lib/email/headerregistry.py | 22 ++++++++-------------- Lib/email/utils.py | 14 +++----------- .../2019-09-19-19-58-33.bpo-34002.KBnaVX.rst | 2 ++ 3 files changed, 13 insertions(+), 25 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2019-09-19-19-58-33.bpo-34002.KBnaVX.rst diff --git a/Lib/email/headerregistry.py b/Lib/email/headerregistry.py index dcc960b..cc1d191 100644 --- a/Lib/email/headerregistry.py +++ b/Lib/email/headerregistry.py @@ -69,11 +69,9 @@ class Address: """The addr_spec (username@domain) portion of the address, quoted according to RFC 5322 rules, but with no Content Transfer Encoding. """ - nameset = set(self.username) - if len(nameset) > len(nameset-parser.DOT_ATOM_ENDS): - lp = parser.quote_string(self.username) - else: - lp = self.username + lp = self.username + if not parser.DOT_ATOM_ENDS.isdisjoint(lp): + lp = parser.quote_string(lp) if self.domain: return lp + '@' + self.domain if not lp: @@ -86,11 +84,9 @@ class Address: self.display_name, self.username, self.domain) def __str__(self): - nameset = set(self.display_name) - if len(nameset) > len(nameset-parser.SPECIALS): - disp = parser.quote_string(self.display_name) - else: - disp = self.display_name + disp = self.display_name + if not parser.SPECIALS.isdisjoint(disp): + disp = parser.quote_string(disp) if disp: addr_spec = '' if self.addr_spec=='<>' else self.addr_spec return "{} <{}>".format(disp, addr_spec) @@ -141,10 +137,8 @@ class Group: if self.display_name is None and len(self.addresses)==1: return str(self.addresses[0]) disp = self.display_name - if disp is not None: - nameset = set(disp) - if len(nameset) > len(nameset-parser.SPECIALS): - disp = parser.quote_string(disp) + if disp is not None and not parser.SPECIALS.isdisjoint(disp): + disp = parser.quote_string(disp) adrstr = ", ".join(str(x) for x in self.addresses) adrstr = ' ' + adrstr if adrstr else adrstr return "{}:{};".format(disp, adrstr) diff --git a/Lib/email/utils.py b/Lib/email/utils.py index 858f620..b137ce3 100644 --- a/Lib/email/utils.py +++ b/Lib/email/utils.py @@ -259,21 +259,13 @@ def decode_params(params): params is a sequence of 2-tuples containing (param name, string value). """ - # Copy params so we don't mess with the original - params = params[:] - new_params = [] + new_params = [params[0]] # Map parameter's name to a list of continuations. The values are a # 3-tuple of the continuation number, the string value, and a flag # specifying whether a particular segment is %-encoded. rfc2231_params = {} - name, value = params.pop(0) - new_params.append((name, value)) - while params: - name, value = params.pop(0) - if name.endswith('*'): - encoded = True - else: - encoded = False + for name, value in params[1:]: + encoded = name.endswith('*') value = unquote(value) mo = rfc2231_continuation.match(name) if mo: diff --git a/Misc/NEWS.d/next/Library/2019-09-19-19-58-33.bpo-34002.KBnaVX.rst b/Misc/NEWS.d/next/Library/2019-09-19-19-58-33.bpo-34002.KBnaVX.rst new file mode 100644 index 0000000..5d4c231 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2019-09-19-19-58-33.bpo-34002.KBnaVX.rst @@ -0,0 +1,2 @@ +Improve efficiency in parts of email package by changing while-pop to a for +loop, using isdisjoint instead of set intersections. -- cgit v0.12