rust-nodemap: accounting for dead blocks
By the very append-only nature of the `NodeTree`, inserting
new blocks has the effect of making some of the older ones
useless as they become unreachable.
Therefore some automatic housekeeping will need to be provided.
This is standard procedure in the word of databases, under names
such as "repack" or "vacuum".
The new `masked_readonly_blocks()` will provide callers with
useful information to decide if the nodetree is ripe for
repacking, but all the `NodeTree` can provide is how many
blocks have been masked in the currently mutable part. Analysing
the readonly part would be way too long to do it for each
transaction and defeat the whole purpose of nodemap persistence.
Serializing callers (from the Python layer) will get this figure
before each extraction and maintain an aggregate counter of
unreachable blocks separately.
Note: at this point, the most efficient repacking is just to restart
afresh with a full rescan.
Differential Revision: https://phab.mercurial-scm.org/D8097
from __future__ import absolute_import
import unittest
from mercurial import error, mdiff
from mercurial.utils import stringutil
# for readability, line numbers are 0-origin
text1 = b'''
00 at OLD
01 at OLD
02 at OLD
02 at NEW, 03 at OLD
03 at NEW, 04 at OLD
04 at NEW, 05 at OLD
05 at NEW, 06 at OLD
07 at OLD
08 at OLD
09 at OLD
10 at OLD
11 at OLD
'''[
1:
] # strip initial LF
text2 = b'''
00 at NEW
01 at NEW
02 at NEW, 03 at OLD
03 at NEW, 04 at OLD
04 at NEW, 05 at OLD
05 at NEW, 06 at OLD
06 at NEW
07 at NEW
08 at NEW
09 at NEW
10 at NEW
11 at NEW
'''[
1:
] # strip initial LF
def filteredblocks(blocks, rangeb):
"""return `rangea` extracted from `blocks` coming from
`mdiff.blocksinrange` along with the mask of blocks within rangeb.
"""
filtered, rangea = mdiff.blocksinrange(blocks, rangeb)
skipped = [b not in filtered for b in blocks]
return rangea, skipped
class blocksinrangetests(unittest.TestCase):
def setUp(self):
self.blocks = list(mdiff.allblocks(text1, text2))
assert self.blocks == [
([0, 3, 0, 2], b'!'),
((3, 7, 2, 6), b'='),
([7, 12, 6, 12], b'!'),
((12, 12, 12, 12), b'='),
], self.blocks
def testWithinEqual(self):
"""linerange within an "=" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^^
linerange2 = (3, 5)
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (4, 6))
self.assertEqual(skipped, [True, False, True, True])
def testWithinEqualStrictly(self):
"""linerange matching exactly an "=" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^^^^
linerange2 = (2, 6)
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (3, 7))
self.assertEqual(skipped, [True, False, True, True])
def testWithinEqualLowerbound(self):
"""linerange at beginning of an "=" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^^
linerange2 = (2, 4)
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (3, 5))
self.assertEqual(skipped, [True, False, True, True])
def testWithinEqualLowerboundOneline(self):
"""oneline-linerange at beginning of an "=" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^
linerange2 = (2, 3)
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (3, 4))
self.assertEqual(skipped, [True, False, True, True])
def testWithinEqualUpperbound(self):
"""linerange at end of an "=" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^^^
linerange2 = (3, 6)
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (4, 7))
self.assertEqual(skipped, [True, False, True, True])
def testWithinEqualUpperboundOneLine(self):
"""oneline-linerange at end of an "=" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^
linerange2 = (5, 6)
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (6, 7))
self.assertEqual(skipped, [True, False, True, True])
def testWithinFirstBlockNeq(self):
"""linerange within the first "!" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^
# | (empty)
# ^
# ^^
for linerange2 in [
(0, 1),
(1, 1),
(1, 2),
(0, 2),
]:
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (0, 3))
self.assertEqual(skipped, [False, True, True, True])
def testWithinLastBlockNeq(self):
"""linerange within the last "!" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^
# ^
# | (empty)
# ^^^^^^
# ^
for linerange2 in [
(6, 7),
(7, 8),
(7, 7),
(6, 12),
(11, 12),
]:
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (7, 12))
self.assertEqual(skipped, [True, True, False, True])
def testAccrossTwoBlocks(self):
"""linerange accross two blocks"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^^^^
linerange2 = (1, 5)
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (0, 6))
self.assertEqual(skipped, [False, False, True, True])
def testCrossingSeveralBlocks(self):
"""linerange accross three blocks"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^^^^^^^
linerange2 = (1, 8)
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, (0, 12))
self.assertEqual(skipped, [False, False, False, True])
def testStartInEqBlock(self):
"""linerange starting in an "=" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^^^^
# ^^^^^^^
for linerange2, expectedlinerange1 in [
((5, 9), (6, 12)),
((4, 11), (5, 12)),
]:
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, expectedlinerange1)
self.assertEqual(skipped, [True, False, False, True])
def testEndInEqBlock(self):
"""linerange ending in an "=" block"""
# IDX 0 1
# 012345678901
# SRC NNOOOONNNNNN (New/Old)
# ^^
# ^^^^^
for linerange2, expectedlinerange1 in [
((1, 3), (0, 4)),
((0, 4), (0, 5)),
]:
linerange1, skipped = filteredblocks(self.blocks, linerange2)
self.assertEqual(linerange1, expectedlinerange1)
self.assertEqual(skipped, [False, False, True, True])
def testOutOfRange(self):
"""linerange exceeding file size"""
exctype = error.Abort
for linerange2 in [
(0, 34),
(15, 12),
]:
# Could be `with self.assertRaises(error.Abort)` but python2.6
# does not have assertRaises context manager.
try:
mdiff.blocksinrange(self.blocks, linerange2)
except exctype as exc:
self.assertTrue(
b'line range exceeds file size'
in stringutil.forcebytestr(exc)
)
else:
self.fail('%s not raised' % exctype.__name__)
if __name__ == '__main__':
import silenttestrunner
silenttestrunner.main(__name__)