Mercurial > cpython-lru_cache-weakref

annotate Doc/includes/sqlite3/text_factory.py @ 87690:66c1c9f32567 default tip

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Add use_weakref option to functools.lru_cache The use_weakref option makes lru_cache create weak references to the function arguments when creating the cache key, which prevents them from staying in the memory forever even after all other references to them are gone. This is a proof of concept for http://bugs.python.org/issue19859
author Radomir Dopieralski <devel@sheep.art.pl>
date Tue, 03 Dec 2013 16:02:48 +0100
parents ba5b337ecc27
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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1 import sqlite3
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2
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3 con = sqlite3.connect(":memory:")
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4 cur = con.cursor()
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5
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6 AUSTRIA = "\xd6sterreich"
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7
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8 # by default, rows are returned as Unicode
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9 cur.execute("select ?", (AUSTRIA,))
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10 row = cur.fetchone()
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11 assert row[0] == AUSTRIA
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12
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13 # but we can make sqlite3 always return bytestrings ...
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14 con.text_factory = bytes
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15 cur.execute("select ?", (AUSTRIA,))
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16 row = cur.fetchone()
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17 assert type(row[0]) is bytes
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18 # the bytestrings will be encoded in UTF-8, unless you stored garbage in the
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19 # database ...
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20 assert row[0] == AUSTRIA.encode("utf-8")
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21
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22 # we can also implement a custom text_factory ...
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23 # here we implement one that appends "foo" to all strings
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24 con.text_factory = lambda x: x.decode("utf-8") + "foo"
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25 cur.execute("select ?", ("bar",))
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26 row = cur.fetchone()
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27 assert row[0] == "barfoo"