1
# Copyright (C) 2009 Canonical Ltd
3
# This program is free software; you can redistribute it and/or modify
4
# it under the terms of the GNU General Public License as published by
5
# the Free Software Foundation; either version 2 of the License, or
6
# (at your option) any later version.
8
# This program is distributed in the hope that it will be useful,
9
# but WITHOUT ANY WARRANTY; without even the implied warranty of
10
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11
# GNU General Public License for more details.
13
# You should have received a copy of the GNU General Public License
14
# along with this program; if not, write to the Free Software
15
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17
"""A manager of caches."""
20
from bzrlib import lru_cache, trace
21
from bzrlib.plugins.fastimport import helpers
23
class CacheManager(object):
25
def __init__(self, info=None, verbose=False, inventory_cache_size=10):
26
"""Create a manager of caches.
28
:param info: a ConfigObj holding the output from
29
the --info processor, or None if no hints are available
31
self.verbose = verbose
33
# dataref -> data. datref is either :mark or the sha-1.
34
# Sticky blobs aren't removed after being referenced.
36
self._sticky_blobs = {}
38
# revision-id -> Inventory cache
39
# these are large and we probably don't need too many as
40
# most parents are recent in history
41
self.inventories = lru_cache.LRUCache(inventory_cache_size)
43
# import commmit-ids -> revision-id lookup table
44
# we need to keep all of these but they are small
45
self.revision_ids = {}
47
# (path, branch_ref) -> file-ids - as generated.
48
# (Use store_file_id/fetch_fileid methods rather than direct access.)
50
# Head tracking: last ref, last id per ref & map of commit ids to ref*s*
55
# Work out the blobs to make sticky - None means all
56
self._blob_ref_counts = {}
59
blobs_by_counts = info['Blob reference counts']
60
# The parser hands values back as lists, already parsed
61
for count, blob_list in blobs_by_counts.items():
64
self._blob_ref_counts[b] = n
66
# info not in file - possible when no blobs used
69
def dump_stats(self, note=trace.note):
70
"""Dump some statistics about what we cached."""
71
# TODO: add in inventory stastistics
72
note("Cache statistics:")
73
self._show_stats_for(self._sticky_blobs, "sticky blobs", note=note)
74
self._show_stats_for(self.revision_ids, "revision-ids", note=note)
75
# These aren't interesting so omit from the output, at least for now
76
#self._show_stats_for(self._blobs, "other blobs", note=note)
77
#self._show_stats_for(self.last_ids, "last-ids", note=note)
78
#self._show_stats_for(self.heads, "heads", note=note)
80
def _show_stats_for(self, dict, label, note=trace.note, tuple_key=False):
81
"""Dump statistics about a given dictionary.
83
By the key and value need to support len().
87
size = sum(map(len, (''.join(k) for k in dict.keys())))
89
size = sum(map(len, dict.keys()))
90
size += sum(map(len, dict.values()))
91
size = size * 1.0 / 1024
99
note(" %-12s: %8.1f %s (%d %s)" % (label, size, unit, count,
100
helpers.single_plural(count, "item", "items")))
103
"""Free up any memory used by the caches."""
105
self._sticky_blobs.clear()
106
self.revision_ids.clear()
107
self.last_ids.clear()
109
self.inventories.clear()
111
def store_blob(self, id, data):
112
"""Store a blob of data."""
113
# Note: If we're not reference counting, everything has to be sticky
114
if not self._blob_ref_counts or id in self._blob_ref_counts:
115
self._sticky_blobs[id] = data
117
# Empty data is always sticky
118
self._sticky_blobs[id] = data
120
self._blobs[id] = data
122
def fetch_blob(self, id):
123
"""Fetch a blob of data."""
125
b = self._sticky_blobs[id]
126
if self._blob_ref_counts and b != '':
127
self._blob_ref_counts[id] -= 1
128
if self._blob_ref_counts[id] == 0:
129
del self._sticky_blobs[id]
132
return self._blobs.pop(id)
134
def track_heads(self, cmd):
135
"""Track the repository heads given a CommitCommand.
137
:param cmd: the CommitCommand
138
:return: the list of parents in terms of commit-ids
140
# Get the true set of parents
141
if cmd.from_ is not None:
142
parents = [cmd.from_]
144
last_id = self.last_ids.get(cmd.ref)
145
if last_id is not None:
149
parents.extend(cmd.merges)
152
self.track_heads_for_ref(cmd.ref, cmd.id, parents)
155
def track_heads_for_ref(self, cmd_ref, cmd_id, parents=None):
156
if parents is not None:
157
for parent in parents:
158
if parent in self.heads:
159
del self.heads[parent]
160
self.heads.setdefault(cmd_id, set()).add(cmd_ref)
161
self.last_ids[cmd_ref] = cmd_id
162
self.last_ref = cmd_ref
added
removed
cache_manager.py
