diff --git a/lib/elements/element.py b/lib/elements/element.py index f978ce5af..746fc8f62 100644 --- a/lib/elements/element.py +++ b/lib/elements/element.py @@ -17,7 +17,7 @@ from ..svg import (PIXELS_PER_MM, apply_transforms, convert_length, get_node_transform) from ..svg.tags import INKSCAPE_LABEL, INKSTITCH_ATTRIBS from ..utils import Point, cache -from ..utils.cache import get_stitch_plan_cache +from ..utils.cache import get_stitch_plan_cache, CacheKeyGenerator class Param(object): @@ -392,12 +392,29 @@ class EmbroideryElement(object): @debug.time def _load_cached_stitch_groups(self): - return get_stitch_plan_cache().get(self.node.get('id')) + return get_stitch_plan_cache().get(self._get_cache_key()) @debug.time def _save_cached_stitch_groups(self, stitch_groups): stitch_plan_cache = get_stitch_plan_cache() - stitch_plan_cache[self.node.get('id')] = stitch_groups + stitch_plan_cache[self._get_cache_key()] = stitch_groups + + def get_params_and_values(self): + params = {} + for param in self.get_params(): + params[param.name] = self.get_param(param.name, param.default) + + return params + + @cache + def _get_cache_key(self): + cache_key_generator = CacheKeyGenerator() + cache_key_generator.update(self.__class__.__name__) + cache_key_generator.update(self.get_params_and_values()) + cache_key_generator.update(self.parse_path()) + cache_key_generator.update(list(self._get_specified_style().items())) + # TODO: include commands and patterns that apply to this element + return cache_key_generator.get_cache_key() def embroider(self, last_stitch_group): stitch_groups = self._load_cached_stitch_groups() diff --git a/lib/utils/cache.py b/lib/utils/cache.py index 46d8ec59b..767978ca4 100644 --- a/lib/utils/cache.py +++ b/lib/utils/cache.py @@ -4,6 +4,8 @@ # Licensed under the GNU GPL version 3.0 or later. See the file LICENSE for details. import os import atexit +import hashlib +import pickle import appdirs import diskcache @@ -31,3 +33,38 @@ def get_stitch_plan_cache(): atexit.register(__stitch_plan_cache.close) return __stitch_plan_cache + + +class CacheKeyGenerator(object): + """Generate cache keys given arbitrary data. + + Given arbitrary data, generate short cache key that is extremely likely + to be unique. + + Use example: + + >>> generator = CacheKeyGenerator() + >>> generator.update(b'12345') + >>> generator.update([1, 2, 3, {4, 5, 6}]) + >>> generator.get_cache_key() + """ + + def __init__(self): + # SHA1 is chosen for speed. We don't need cryptography-grade hashing + # for this use case. + self._hasher = hashlib.sha1() + + def update(self, data): + """Provide data to be hashed into a cache key. + + Arguments: + data -- a bytes object or any object that can be pickled + """ + + if not isinstance(data, bytes): + data = pickle.dumps(data) + + self._hasher.update(data) + + def get_cache_key(self): + return self._hasher.hexdigest()