(user_function, maxsize, typed, _CacheInfo)
| 523 | return decorating_function |
| 524 | |
| 525 | def _lru_cache_wrapper(user_function, maxsize, typed, _CacheInfo): |
| 526 | # Constants shared by all lru cache instances: |
| 527 | sentinel = object() # unique object used to signal cache misses |
| 528 | make_key = _make_key # build a key from the function arguments |
| 529 | PREV, NEXT, KEY, RESULT = 0, 1, 2, 3 # names for the link fields |
| 530 | |
| 531 | cache = {} |
| 532 | hits = misses = 0 |
| 533 | full = False |
| 534 | cache_get = cache.get # bound method to lookup a key or return None |
| 535 | cache_len = cache.__len__ # get cache size without calling len() |
| 536 | lock = RLock() # because linkedlist updates aren't threadsafe |
| 537 | root = [] # root of the circular doubly linked list |
| 538 | root[:] = [root, root, None, None] # initialize by pointing to self |
| 539 | |
| 540 | if maxsize == 0: |
| 541 | |
| 542 | def wrapper(*args, **kwds): |
| 543 | # No caching -- just a statistics update |
| 544 | nonlocal misses |
| 545 | misses += 1 |
| 546 | result = user_function(*args, **kwds) |
| 547 | return result |
| 548 | |
| 549 | elif maxsize is None: |
| 550 | |
| 551 | def wrapper(*args, **kwds): |
| 552 | # Simple caching without ordering or size limit |
| 553 | nonlocal hits, misses |
| 554 | key = make_key(args, kwds, typed) |
| 555 | result = cache_get(key, sentinel) |
| 556 | if result is not sentinel: |
| 557 | hits += 1 |
| 558 | return result |
| 559 | misses += 1 |
| 560 | result = user_function(*args, **kwds) |
| 561 | cache[key] = result |
| 562 | return result |
| 563 | |
| 564 | else: |
| 565 | |
| 566 | def wrapper(*args, **kwds): |
| 567 | # Size limited caching that tracks accesses by recency |
| 568 | nonlocal root, hits, misses, full |
| 569 | key = make_key(args, kwds, typed) |
| 570 | with lock: |
| 571 | link = cache_get(key) |
| 572 | if link is not None: |
| 573 | # Move the link to the front of the circular queue |
| 574 | link_prev, link_next, _key, result = link |
| 575 | link_prev[NEXT] = link_next |
| 576 | link_next[PREV] = link_prev |
| 577 | last = root[PREV] |
| 578 | last[NEXT] = root[PREV] = link |
| 579 | link[PREV] = last |
| 580 | link[NEXT] = root |
| 581 | hits += 1 |
| 582 | return result |
no test coverage detected