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# Copyright (C) 2009 Canonical Ltd
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
"""A manager of caches."""
from bzrlib import lru_cache, trace
from bzrlib.plugins.fastimport import branch_mapper, helpers
class CacheManager(object):
def __init__(self, info=None, verbose=False, inventory_cache_size=10):
"""Create a manager of caches.
:param info: a ConfigObj holding the output from
the --info processor, or None if no hints are available
"""
self.verbose = verbose
# dataref -> data. datref is either :mark or the sha-1.
# Sticky blobs aren't removed after being referenced.
self._blobs = {}
self._sticky_blobs = {}
# revision-id -> Inventory cache
# these are large and we probably don't need too many as
# most parents are recent in history
self.inventories = lru_cache.LRUCache(inventory_cache_size)
# import commmit-ids -> revision-id lookup table
# we need to keep all of these but they are small
self.revision_ids = {}
# (path, branch_ref) -> file-ids - as generated.
# (Use store_file_id/fetch_fileid methods rather than direct access.)
# Head tracking: last ref, last id per ref & map of commit ids to ref*s*
self.last_ref = None
self.last_ids = {}
self.heads = {}
# Work out the blobs to make sticky - None means all
self._blob_ref_counts = {}
if info is not None:
try:
blobs_by_counts = info['Blob reference counts']
# The parser hands values back as lists, already parsed
for count, blob_list in blobs_by_counts.items():
n = int(count)
for b in blob_list:
self._blob_ref_counts[b] = n
except KeyError:
# info not in file - possible when no blobs used
pass
# BranchMapper has no state (for now?), but we keep it around rather
# than reinstantiate on every usage
self.branch_mapper = branch_mapper.BranchMapper()
def dump_stats(self, note=trace.note):
"""Dump some statistics about what we cached."""
# TODO: add in inventory stastistics
note("Cache statistics:")
self._show_stats_for(self._sticky_blobs, "sticky blobs", note=note)
self._show_stats_for(self.revision_ids, "revision-ids", note=note)
# These aren't interesting so omit from the output, at least for now
#self._show_stats_for(self._blobs, "other blobs", note=note)
#self._show_stats_for(self.last_ids, "last-ids", note=note)
#self._show_stats_for(self.heads, "heads", note=note)
def _show_stats_for(self, dict, label, note=trace.note, tuple_key=False):
"""Dump statistics about a given dictionary.
By the key and value need to support len().
"""
count = len(dict)
if tuple_key:
size = sum(map(len, (''.join(k) for k in dict.keys())))
else:
size = sum(map(len, dict.keys()))
size += sum(map(len, dict.values()))
size = size * 1.0 / 1024
unit = 'K'
if size > 1024:
size = size / 1024
unit = 'M'
if size > 1024:
size = size / 1024
unit = 'G'
note(" %-12s: %8.1f %s (%d %s)" % (label, size, unit, count,
helpers.single_plural(count, "item", "items")))
def clear_all(self):
"""Free up any memory used by the caches."""
self._blobs.clear()
self._sticky_blobs.clear()
self.revision_ids.clear()
self.last_ids.clear()
self.heads.clear()
self.inventories.clear()
def store_blob(self, id, data):
"""Store a blob of data."""
# Note: If we're not reference counting, everything has to be sticky
if not self._blob_ref_counts or id in self._blob_ref_counts:
self._sticky_blobs[id] = data
elif data == '':
# Empty data is always sticky
self._sticky_blobs[id] = data
else:
self._blobs[id] = data
def fetch_blob(self, id):
"""Fetch a blob of data."""
try:
b = self._sticky_blobs[id]
if self._blob_ref_counts and b != '':
self._blob_ref_counts[id] -= 1
if self._blob_ref_counts[id] == 0:
del self._sticky_blobs[id]
return b
except KeyError:
return self._blobs.pop(id)
def track_heads(self, cmd):
"""Track the repository heads given a CommitCommand.
:param cmd: the CommitCommand
:return: the list of parents in terms of commit-ids
"""
# Get the true set of parents
if cmd.from_ is not None:
parents = [cmd.from_]
else:
last_id = self.last_ids.get(cmd.ref)
if last_id is not None:
parents = [last_id]
else:
parents = []
parents.extend(cmd.merges)
# Track the heads
self.track_heads_for_ref(cmd.ref, cmd.id, parents)
return parents
def track_heads_for_ref(self, cmd_ref, cmd_id, parents=None):
if parents is not None:
for parent in parents:
if parent in self.heads:
del self.heads[parent]
self.heads.setdefault(cmd_id, set()).add(cmd_ref)
self.last_ids[cmd_ref] = cmd_id
self.last_ref = cmd_ref
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