bup repositories are in Git format. This library allows us to
interact with the Git data structures.
"""
-import os, zlib, time, subprocess, struct, stat, re, tempfile
-import heapq
+import os, sys, zlib, time, subprocess, struct, stat, re, tempfile, math, glob
from bup.helpers import *
-from bup import _helpers
-
-MIDX_VERSION = 2
+from bup import _helpers, path
+
+MIDX_VERSION = 4
+
+"""Discussion of bloom constants for bup:
+
+There are four basic things to consider when building a bloom filter:
+The size, in bits, of the filter
+The capacity, in entries, of the filter
+The probability of a false positive that is tolerable
+The number of bits readily available to use for addresing filter bits
+
+There is one major tunable that is not directly related to the above:
+k: the number of bits set in the filter per entry
+
+Here's a wall of numbers showing the relationship between k; the ratio between
+the filter size in bits and the entries in the filter; and pfalse_positive:
+
+mn|k=3 |k=4 |k=5 |k=6 |k=7 |k=8 |k=9 |k=10 |k=11
+ 8|3.05794|2.39687|2.16792|2.15771|2.29297|2.54917|2.92244|3.41909|4.05091
+ 9|2.27780|1.65770|1.40703|1.32721|1.34892|1.44631|1.61138|1.84491|2.15259
+10|1.74106|1.18133|0.94309|0.84362|0.81937|0.84555|0.91270|1.01859|1.16495
+11|1.36005|0.86373|0.65018|0.55222|0.51259|0.50864|0.53098|0.57616|0.64387
+12|1.08231|0.64568|0.45945|0.37108|0.32939|0.31424|0.31695|0.33387|0.36380
+13|0.87517|0.49210|0.33183|0.25527|0.21689|0.19897|0.19384|0.19804|0.21013
+14|0.71759|0.38147|0.24433|0.17934|0.14601|0.12887|0.12127|0.12012|0.12399
+15|0.59562|0.30019|0.18303|0.12840|0.10028|0.08523|0.07749|0.07440|0.07468
+16|0.49977|0.23941|0.13925|0.09351|0.07015|0.05745|0.05049|0.04700|0.04587
+17|0.42340|0.19323|0.10742|0.06916|0.04990|0.03941|0.03350|0.03024|0.02870
+18|0.36181|0.15765|0.08392|0.05188|0.03604|0.02748|0.02260|0.01980|0.01827
+19|0.31160|0.12989|0.06632|0.03942|0.02640|0.01945|0.01549|0.01317|0.01182
+20|0.27026|0.10797|0.05296|0.03031|0.01959|0.01396|0.01077|0.00889|0.00777
+21|0.23591|0.09048|0.04269|0.02356|0.01471|0.01014|0.00759|0.00609|0.00518
+22|0.20714|0.07639|0.03473|0.01850|0.01117|0.00746|0.00542|0.00423|0.00350
+23|0.18287|0.06493|0.02847|0.01466|0.00856|0.00555|0.00392|0.00297|0.00240
+24|0.16224|0.05554|0.02352|0.01171|0.00663|0.00417|0.00286|0.00211|0.00166
+25|0.14459|0.04779|0.01957|0.00944|0.00518|0.00316|0.00211|0.00152|0.00116
+26|0.12942|0.04135|0.01639|0.00766|0.00408|0.00242|0.00157|0.00110|0.00082
+27|0.11629|0.03595|0.01381|0.00626|0.00324|0.00187|0.00118|0.00081|0.00059
+28|0.10489|0.03141|0.01170|0.00515|0.00259|0.00146|0.00090|0.00060|0.00043
+29|0.09492|0.02756|0.00996|0.00426|0.00209|0.00114|0.00069|0.00045|0.00031
+30|0.08618|0.02428|0.00853|0.00355|0.00169|0.00090|0.00053|0.00034|0.00023
+31|0.07848|0.02147|0.00733|0.00297|0.00138|0.00072|0.00041|0.00025|0.00017
+32|0.07167|0.01906|0.00633|0.00250|0.00113|0.00057|0.00032|0.00019|0.00013
+
+Here's a table showing available repository size for a given pfalse_positive
+and three values of k (assuming we only use the 160 bit SHA1 for addressing the
+filter and 8192bytes per object):
+
+pfalse|obj k=4 |cap k=4 |obj k=5 |cap k=5 |obj k=6 |cap k=6
+2.500%|139333497228|1038.11 TiB|558711157|4262.63 GiB|13815755|105.41 GiB
+1.000%|104489450934| 778.50 TiB|436090254|3327.10 GiB|11077519| 84.51 GiB
+0.125%| 57254889824| 426.58 TiB|261732190|1996.86 GiB| 7063017| 55.89 GiB
+
+This eliminates pretty neatly any k>6 as long as we use the raw SHA for
+addressing.
+
+filter size scales linearly with repository size for a given k and pfalse.
+
+Here's a table of filter sizes for a 1 TiB repository:
+
+pfalse| k=3 | k=4 | k=5 | k=6
+2.500%| 138.78 MiB | 126.26 MiB | 123.00 MiB | 123.37 MiB
+1.000%| 197.83 MiB | 168.36 MiB | 157.58 MiB | 153.87 MiB
+0.125%| 421.14 MiB | 307.26 MiB | 262.56 MiB | 241.32 MiB
+
+For bup:
+* We want the bloom filter to fit in memory; if it doesn't, the k pagefaults
+per lookup will be worse than the two required for midx.
+* We want the pfalse_positive to be low enough that the cost of sometimes
+faulting on the midx doesn't overcome the benefit of the bloom filter.
+* We have readily available 160 bits for addressing the filter.
+* We want to be able to have a single bloom address entire repositories of
+reasonable size.
+
+Based on these parameters, a combination of k=4 and k=5 provides the behavior
+that bup needs. As such, I've implemented bloom addressing, adding and
+checking functions in C for these two values. Because k=5 requires less space
+and gives better overall pfalse_positive perofrmance, it is preferred if a
+table with k=5 can represent the repository.
+
+None of this tells us what max_pfalse_positive to choose.
+
+Brandon Low <lostlogic@lostlogicx.com> 04-02-2011
+"""
+BLOOM_VERSION = 2
+MAX_BITS_EACH = 32 # Kinda arbitrary, but 4 bytes per entry is pretty big
+MAX_BLOOM_BITS = {4: 37, 5: 29} # 160/k-log2(8)
+MAX_PFALSE_POSITIVE = 1. # Totally arbitrary, needs benchmarking
verbose = 0
ignore_midx = 0
def auto_midx(objdir):
- main_exe = os.environ.get('BUP_MAIN_EXE') or sys.argv[0]
- args = [main_exe, 'midx', '--auto', '--dir', objdir]
- rv = subprocess.call(args, stdout=open('/dev/null', 'w'))
+ args = [path.exe(), 'midx', '--auto', '--dir', objdir]
+ try:
+ rv = subprocess.call(args, stdout=open('/dev/null', 'w'))
+ except OSError, e:
+ # make sure 'args' gets printed to help with debugging
+ add_error('%r: exception: %s' % (args, e))
+ raise
+ if rv:
+ add_error('%r: returned %d' % (args, rv))
+
+ args = [path.exe(), 'bloom', '--dir', objdir]
+ try:
+ rv = subprocess.call(args, stdout=open('/dev/null', 'w'))
+ except OSError, e:
+ # make sure 'args' gets printed to help with debugging
+ add_error('%r: exception: %s' % (args, e))
+ raise
if rv:
add_error('%r: returned %d' % (args, rv))
class PackIdx:
- """Object representation of a Git pack index file."""
- def __init__(self, filename):
- self.name = filename
- self.idxnames = [self.name]
- self.map = mmap_read(open(filename))
- assert(str(self.map[0:8]) == '\377tOc\0\0\0\2')
- self.fanout = list(struct.unpack('!256I',
- str(buffer(self.map, 8, 256*4))))
- self.fanout.append(0) # entry "-1"
- nsha = self.fanout[255]
- self.ofstable = buffer(self.map,
- 8 + 256*4 + nsha*20 + nsha*4,
- nsha*4)
- self.ofs64table = buffer(self.map,
- 8 + 256*4 + nsha*20 + nsha*4 + nsha*4)
+ def __init__(self):
+ assert(0)
- def _ofs_from_idx(self, idx):
- ofs = struct.unpack('!I', str(buffer(self.ofstable, idx*4, 4)))[0]
- if ofs & 0x80000000:
- idx64 = ofs & 0x7fffffff
- ofs = struct.unpack('!I',
- str(buffer(self.ofs64table, idx64*8, 8)))[0]
- return ofs
+ def find_offset(self, hash):
+ """Get the offset of an object inside the index file."""
+ idx = self._idx_from_hash(hash)
+ if idx != None:
+ return self._ofs_from_idx(idx)
+ return None
+
+ def exists(self, hash, want_source=False):
+ """Return nonempty if the object exists in this index."""
+ if hash and (self._idx_from_hash(hash) != None):
+ return want_source and self.name or True
+ return None
+
+ def __len__(self):
+ return int(self.fanout[255])
def _idx_from_hash(self, hash):
global _total_searches, _total_steps
b1 = ord(hash[0])
start = self.fanout[b1-1] # range -1..254
end = self.fanout[b1] # range 0..255
- buf = buffer(self.map, 8 + 256*4, end*20)
want = str(hash)
_total_steps += 1 # lookup table is a step
while start < end:
_total_steps += 1
mid = start + (end-start)/2
- v = str(buf[mid*20:(mid+1)*20])
+ v = self._idx_to_hash(mid)
if v < want:
start = mid+1
elif v > want:
return mid
return None
- def find_offset(self, hash):
- """Get the offset of an object inside the index file."""
- idx = self._idx_from_hash(hash)
- if idx != None:
- return self._ofs_from_idx(idx)
- return None
- def exists(self, hash):
- """Return nonempty if the object exists in this index."""
- return hash and (self._idx_from_hash(hash) != None) and True or None
+class PackIdxV1(PackIdx):
+ """Object representation of a Git pack index (version 1) file."""
+ def __init__(self, filename, f):
+ self.name = filename
+ self.idxnames = [self.name]
+ self.map = mmap_read(f)
+ self.fanout = list(struct.unpack('!256I',
+ str(buffer(self.map, 0, 256*4))))
+ self.fanout.append(0) # entry "-1"
+ nsha = self.fanout[255]
+ self.sha_ofs = 256*4
+ self.shatable = buffer(self.map, self.sha_ofs, nsha*24)
+
+ def _ofs_from_idx(self, idx):
+ return struct.unpack('!I', str(self.shatable[idx*24 : idx*24+4]))[0]
+
+ def _idx_to_hash(self, idx):
+ return str(self.shatable[idx*24+4 : idx*24+24])
def __iter__(self):
for i in xrange(self.fanout[255]):
- yield buffer(self.map, 8 + 256*4 + 20*i, 20)
+ yield buffer(self.map, 256*4 + 24*i + 4, 20)
- def __len__(self):
- return int(self.fanout[255])
+
+class PackIdxV2(PackIdx):
+ """Object representation of a Git pack index (version 2) file."""
+ def __init__(self, filename, f):
+ self.name = filename
+ self.idxnames = [self.name]
+ self.map = mmap_read(f)
+ assert(str(self.map[0:8]) == '\377tOc\0\0\0\2')
+ self.fanout = list(struct.unpack('!256I',
+ str(buffer(self.map, 8, 256*4))))
+ self.fanout.append(0) # entry "-1"
+ nsha = self.fanout[255]
+ self.sha_ofs = 8 + 256*4
+ self.shatable = buffer(self.map, self.sha_ofs, nsha*20)
+ self.ofstable = buffer(self.map,
+ self.sha_ofs + nsha*20 + nsha*4,
+ nsha*4)
+ self.ofs64table = buffer(self.map,
+ 8 + 256*4 + nsha*20 + nsha*4 + nsha*4)
+
+ def _ofs_from_idx(self, idx):
+ ofs = struct.unpack('!I', str(buffer(self.ofstable, idx*4, 4)))[0]
+ if ofs & 0x80000000:
+ idx64 = ofs & 0x7fffffff
+ ofs = struct.unpack('!Q',
+ str(buffer(self.ofs64table, idx64*8, 8)))[0]
+ return ofs
+
+ def _idx_to_hash(self, idx):
+ return str(self.shatable[idx*20:(idx+1)*20])
+
+ def __iter__(self):
+ for i in xrange(self.fanout[255]):
+ yield buffer(self.map, 8 + 256*4 + 20*i, 20)
extract_bits = _helpers.extract_bits
+bloom_contains = _helpers.bloom_contains
+bloom_add = _helpers.bloom_add
+
+
+class ShaBloom:
+ """Wrapper which contains data from multiple index files.
+ """
+ def __init__(self, filename, f=None, readwrite=False, expected=-1):
+ self.name = filename
+ self.rwfile = None
+ self.map = None
+ assert(filename.endswith('.bloom'))
+ if readwrite:
+ assert(expected > 0)
+ self.rwfile = f = f or open(filename, 'r+b')
+ f.seek(0)
+
+ # Decide if we want to mmap() the pages as writable ('immediate'
+ # write) or else map them privately for later writing back to
+ # the file ('delayed' write). A bloom table's write access
+ # pattern is such that we dirty almost all the pages after adding
+ # very few entries. But the table is so big that dirtying
+ # *all* the pages often exceeds Linux's default
+ # /proc/sys/vm/dirty_ratio or /proc/sys/vm/dirty_background_ratio,
+ # thus causing it to start flushing the table before we're
+ # finished... even though there's more than enough space to
+ # store the bloom table in RAM.
+ #
+ # To work around that behaviour, if we calculate that we'll
+ # probably end up touching the whole table anyway (at least
+ # one bit flipped per memory page), let's use a "private" mmap,
+ # which defeats Linux's ability to flush it to disk. Then we'll
+ # flush it as one big lump during close().
+ pages = os.fstat(f.fileno()).st_size / 4096 * 5 # assume k=5
+ self.delaywrite = expected > pages
+ debug1('bloom: delaywrite=%r\n' % self.delaywrite)
+ if self.delaywrite:
+ self.map = mmap_readwrite_private(self.rwfile, close=False)
+ else:
+ self.map = mmap_readwrite(self.rwfile, close=False)
+ else:
+ self.rwfile = None
+ f = f or open(filename, 'rb')
+ self.map = mmap_read(f)
+ got = str(self.map[0:4])
+ if got != 'BLOM':
+ log('Warning: invalid BLOM header (%r) in %r\n' % (got, filename))
+ return self._init_failed()
+ ver = struct.unpack('!I', self.map[4:8])[0]
+ if ver < BLOOM_VERSION:
+ log('Warning: ignoring old-style (v%d) bloom %r\n'
+ % (ver, filename))
+ return self._init_failed()
+ if ver > BLOOM_VERSION:
+ log('Warning: ignoring too-new (v%d) bloom %r\n'
+ % (ver, filename))
+ return self._init_failed()
+
+ self.bits, self.k, self.entries = struct.unpack('!HHI', self.map[8:16])
+ idxnamestr = str(self.map[16 + 2**self.bits:])
+ if idxnamestr:
+ self.idxnames = idxnamestr.split('\0')
+ else:
+ self.idxnames = []
+
+ def _init_failed(self):
+ if self.map:
+ self.map = None
+ if self.rwfile:
+ self.rwfile.close()
+ self.rwfile = None
+ self.idxnames = []
+ self.bits = self.entries = 0
+
+ def valid(self):
+ return self.map and self.bits
+
+ def __del__(self):
+ self.close()
+
+ def close(self):
+ if self.map and self.rwfile:
+ debug2("bloom: closing with %d entries\n" % self.entries)
+ self.map[12:16] = struct.pack('!I', self.entries)
+ if self.delaywrite:
+ self.rwfile.seek(0)
+ self.rwfile.write(self.map)
+ else:
+ self.map.flush()
+ self.rwfile.seek(16 + 2**self.bits)
+ if self.idxnames:
+ self.rwfile.write('\0'.join(self.idxnames))
+ self._init_failed()
+
+ def pfalse_positive(self, additional=0):
+ n = self.entries + additional
+ m = 8*2**self.bits
+ k = self.k
+ return 100*(1-math.exp(-k*float(n)/m))**k
+
+ def add_idx(self, ix):
+ """Add the object to the filter, return current pfalse_positive."""
+ if not self.map: raise Exception, "Cannot add to closed bloom"
+ self.entries += bloom_add(self.map, ix.shatable, self.bits, self.k)
+ self.idxnames.append(os.path.basename(ix.name))
+
+ def exists(self, sha):
+ """Return nonempty if the object probably exists in the bloom filter."""
+ global _total_searches, _total_steps
+ _total_searches += 1
+ if not self.map: return None
+ found, steps = bloom_contains(self.map, str(sha), self.bits, self.k)
+ _total_steps += steps
+ return found
+
+ @classmethod
+ def create(cls, name, expected, delaywrite=None, f=None, k=None):
+ """Create and return a bloom filter for `expected` entries."""
+ bits = int(math.floor(math.log(expected*MAX_BITS_EACH/8,2)))
+ k = k or ((bits <= MAX_BLOOM_BITS[5]) and 5 or 4)
+ if bits > MAX_BLOOM_BITS[k]:
+ log('bloom: warning, max bits exceeded, non-optimal\n')
+ bits = MAX_BLOOM_BITS[k]
+ debug1('bloom: using 2^%d bytes and %d hash functions\n' % (bits, k))
+ f = f or open(name, 'w+b')
+ f.write('BLOM')
+ f.write(struct.pack('!IHHI', BLOOM_VERSION, bits, k, 0))
+ assert(f.tell() == 16)
+ # NOTE: On some systems this will not extend+zerofill, but it does on
+ # darwin, linux, bsd and solaris.
+ f.truncate(16+2**bits)
+ f.seek(0)
+ if delaywrite != None and not delaywrite:
+ # tell it to expect very few objects, forcing a direct mmap
+ expected = 1
+ return cls(name, f=f, readwrite=True, expected=expected)
+
+ def __len__(self):
+ return self.entries
+
class PackMidx:
"""Wrapper which contains data from multiple index files.
self.bits = _helpers.firstword(self.map[8:12])
self.entries = 2**self.bits
self.fanout = buffer(self.map, 12, self.entries*4)
- shaofs = 12 + self.entries*4
- nsha = self._fanget(self.entries-1)
- self.shalist = buffer(self.map, shaofs, nsha*20)
- self.idxnames = str(self.map[shaofs + 20*nsha:]).split('\0')
+ self.sha_ofs = 12 + self.entries*4
+ self.nsha = nsha = self._fanget(self.entries-1)
+ self.shatable = buffer(self.map, self.sha_ofs, nsha*20)
+ self.whichlist = buffer(self.map, self.sha_ofs + nsha*20, nsha*4)
+ self.idxname_ofs = self.sha_ofs + 24*nsha
+ self.idxnames = str(self.map[self.idxname_ofs:]).split('\0')
def _init_failed(self):
self.bits = 0
self.entries = 1
self.fanout = buffer('\0\0\0\0')
- self.shalist = buffer('\0'*20)
+ self.shatable = buffer('\0'*20)
self.idxnames = []
def _fanget(self, i):
return _helpers.firstword(s)
def _get(self, i):
- return str(self.shalist[i*20:(i+1)*20])
+ return str(self.shatable[i*20:(i+1)*20])
+
+ def _get_idx_i(self, i):
+ return struct.unpack('!I', self.whichlist[i*4:(i+1)*4])[0]
- def exists(self, hash):
+ def _get_idxname(self, i):
+ return self.idxnames[self._get_idx_i(i)]
+
+ def exists(self, hash, want_source=False):
"""Return nonempty if the object exists in the index files."""
global _total_searches, _total_steps
_total_searches += 1
end = mid
endv = _helpers.firstword(v)
else: # got it!
- return True
+ return want_source and self._get_idxname(mid) or True
return None
def __iter__(self):
for i in xrange(self._fanget(self.entries-1)):
- yield buffer(self.shalist, i*20, 20)
+ yield buffer(self.shatable, i*20, 20)
def __len__(self):
return int(self._fanget(self.entries-1))
assert(_mpi_count == 0) # these things suck tons of VM; don't waste it
_mpi_count += 1
self.dir = dir
- self.also = {}
+ self.also = set()
self.packs = []
+ self.do_bloom = False
+ self.bloom = None
self.refresh()
def __del__(self):
def __len__(self):
return sum(len(pack) for pack in self.packs)
- def exists(self, hash):
+ def exists(self, hash, want_source=False):
"""Return nonempty if the object exists in the index files."""
global _total_searches
_total_searches += 1
if hash in self.also:
return True
- for i in range(len(self.packs)):
+ if self.do_bloom and self.bloom is not None:
+ _total_searches -= 1 # will be incremented by bloom
+ if self.bloom.exists(hash):
+ self.do_bloom = False
+ else:
+ return None
+ for i in xrange(len(self.packs)):
p = self.packs[i]
_total_searches -= 1 # will be incremented by sub-pack
- if p.exists(hash):
+ ix = p.exists(hash, want_source=want_source)
+ if ix:
# reorder so most recently used packs are searched first
self.packs = [p] + self.packs[:i] + self.packs[i+1:]
- return p.name
+ return ix
+ self.do_bloom = True
return None
def refresh(self, skip_midx = False):
The module-global variable 'ignore_midx' can force this function to
always act as if skip_midx was True.
"""
+ self.bloom = None # Always reopen the bloom as it may have been relaced
+ self.do_bloom = False
skip_midx = skip_midx or ignore_midx
d = dict((p.name, p) for p in self.packs
if not skip_midx or not isinstance(p, PackMidx))
if isinstance(ix, PackMidx):
for name in ix.idxnames:
d[os.path.join(self.dir, name)] = ix
- for f in os.listdir(self.dir):
- full = os.path.join(self.dir, f)
- if f.endswith('.midx') and not d.get(full):
+ for full in glob.glob(os.path.join(self.dir,'*.midx')):
+ if not d.get(full):
mx = PackMidx(full)
(mxd, mxf) = os.path.split(mx.name)
- broken = 0
+ broken = False
for n in mx.idxnames:
if not os.path.exists(os.path.join(mxd, n)):
log(('warning: index %s missing\n' +
' used by %s\n') % (n, mxf))
- broken += 1
- if not broken:
+ broken = True
+ if broken:
+ del mx
+ unlink(full)
+ else:
midxl.append(mx)
midxl.sort(lambda x,y: -cmp(len(x),len(y)))
for ix in midxl:
- any = 0
+ any_needed = False
for sub in ix.idxnames:
found = d.get(os.path.join(self.dir, sub))
if not found or isinstance(found, PackIdx):
# doesn't exist, or exists but not in a midx
- d[ix.name] = ix
- for name in ix.idxnames:
- d[os.path.join(self.dir, name)] = ix
- any += 1
+ any_needed = True
break
- if not any and not ix.force_keep:
+ if any_needed:
+ d[ix.name] = ix
+ for name in ix.idxnames:
+ d[os.path.join(self.dir, name)] = ix
+ elif not ix.force_keep:
debug1('midx: removing redundant: %s\n'
% os.path.basename(ix.name))
unlink(ix.name)
- for f in os.listdir(self.dir):
- full = os.path.join(self.dir, f)
- if f.endswith('.idx') and not d.get(full):
- ix = PackIdx(full)
+ for full in glob.glob(os.path.join(self.dir,'*.idx')):
+ if not d.get(full):
+ try:
+ ix = open_idx(full)
+ except GitError, e:
+ add_error(e)
+ continue
d[full] = ix
+ bfull = os.path.join(self.dir, 'bup.bloom')
+ if self.bloom is None and os.path.exists(bfull):
+ self.bloom = ShaBloom(bfull)
self.packs = list(set(d.values()))
+ self.packs.sort(lambda x,y: -cmp(len(x),len(y)))
+ if self.bloom and self.bloom.valid() and len(self.bloom) >= len(self):
+ self.do_bloom = True
+ else:
+ self.bloom = None
debug1('PackIdxList: using %d index%s.\n'
% (len(self.packs), len(self.packs)!=1 and 'es' or ''))
def add(self, hash):
"""Insert an additional object in the list."""
- self.also[hash] = 1
-
- def zap_also(self):
- """Remove all additional objects from the list."""
- self.also = {}
+ self.also.add(hash)
def calc_hash(type, content):
def open_idx(filename):
if filename.endswith('.idx'):
- return PackIdx(filename)
+ f = open(filename, 'rb')
+ header = f.read(8)
+ if header[0:4] == '\377tOc':
+ version = struct.unpack('!I', header[4:8])[0]
+ if version == 2:
+ return PackIdxV2(filename, f)
+ else:
+ raise GitError('%s: expected idx file version 2, got %d'
+ % (filename, version))
+ elif len(header) == 8 and header[0:4] < '\377tOc':
+ return PackIdxV1(filename, f)
+ else:
+ raise GitError('%s: unrecognized idx file header' % filename)
elif filename.endswith('.midx'):
return PackMidx(filename)
else:
def idxmerge(idxlist, final_progress=True):
"""Generate a list of all the objects reachable in a PackIdxList."""
- total = sum(len(i) for i in idxlist)
- iters = (iter(i) for i in idxlist)
- heap = [(next(it), it) for it in iters]
- heapq.heapify(heap)
- count = 0
- last = None
- while heap:
- if (count % 10024) == 0:
- progress('Reading indexes: %.2f%% (%d/%d)\r'
- % (count*100.0/total, count, total))
- (e, it) = heap[0]
- if e != last:
- yield e
- last = e
- count += 1
- e = next(it)
- if e:
- heapq.heapreplace(heap, (e, it))
- else:
- heapq.heappop(heap)
- if final_progress:
- log('Reading indexes: %.2f%% (%d/%d), done.\n' % (100, total, total))
+ def pfunc(count, total):
+ progress('Reading indexes: %.2f%% (%d/%d)\r'
+ % (count*100.0/total, count, total))
+ def pfinal(count, total):
+ if final_progress:
+ log('Reading indexes: %.2f%% (%d/%d), done.\n' % (100, total, total))
+ return merge_iter(idxlist, 10024, pfunc, pfinal)
+def _make_objcache():
+ return PackIdxList(repo('objects/pack'))
+
class PackWriter:
"""Writes Git objects insid a pack file."""
- def __init__(self, objcache_maker=None):
+ def __init__(self, objcache_maker=_make_objcache):
self.count = 0
self.outbytes = 0
self.filename = None
self.file = None
+ self.idx = None
self.objcache_maker = objcache_maker
self.objcache = None
def __del__(self):
self.close()
- def _make_objcache(self):
- if self.objcache == None:
- if self.objcache_maker:
- self.objcache = self.objcache_maker()
- else:
- self.objcache = PackIdxList(repo('objects/pack'))
-
def _open(self):
if not self.file:
- self._make_objcache()
(fd,name) = tempfile.mkstemp(suffix='.pack', dir=repo('objects'))
self.file = os.fdopen(fd, 'w+b')
assert(name.endswith('.pack'))
self.filename = name[:-5]
self.file.write('PACK\0\0\0\2\0\0\0\0')
+ self.idx = list(list() for i in xrange(256))
- def _raw_write(self, datalist):
+ # the 'sha' parameter is used in client.py's _raw_write(), but not needed
+ # in this basic version.
+ def _raw_write(self, datalist, sha):
self._open()
f = self.file
# in case we get interrupted (eg. KeyboardInterrupt), it's best if
# to our hashsplit algorithm.) f.write() does its own buffering,
# but that's okay because we'll flush it in _end().
oneblob = ''.join(datalist)
- f.write(oneblob)
- self.outbytes += len(oneblob)
+ try:
+ f.write(oneblob)
+ except IOError, e:
+ raise GitError, e, sys.exc_info()[2]
+ nw = len(oneblob)
+ crc = zlib.crc32(oneblob) & 0xffffffff
+ self._update_idx(sha, crc, nw)
+ self.outbytes += nw
self.count += 1
+ return nw, crc
- def _write(self, bin, type, content):
+ def _update_idx(self, sha, crc, size):
+ assert(sha)
+ if self.idx:
+ self.idx[ord(sha[0])].append((sha, crc, self.file.tell() - size))
+
+ def _write(self, sha, type, content):
if verbose:
log('>')
- self._raw_write(_encode_packobj(type, content))
- return bin
+ if not sha:
+ sha = calc_hash(type, content)
+ size, crc = self._raw_write(_encode_packobj(type, content), sha=sha)
+ return sha
def breakpoint(self):
"""Clear byte and object counts and return the last processed id."""
self.outbytes = self.count = 0
return id
- def write(self, type, content):
- """Write an object in this pack file."""
- return self._write(calc_hash(type, content), type, content)
+ def _require_objcache(self):
+ if self.objcache is None and self.objcache_maker:
+ self.objcache = self.objcache_maker()
+ if self.objcache is None:
+ raise GitError(
+ "PackWriter not opened or can't check exists w/o objcache")
- def exists(self, id):
+ def exists(self, id, want_source=False):
"""Return non-empty if an object is found in the object cache."""
- if not self.objcache:
- self._make_objcache()
- return self.objcache.exists(id)
+ self._require_objcache()
+ return self.objcache.exists(id, want_source=want_source)
def maybe_write(self, type, content):
"""Write an object to the pack file if not present and return its id."""
- bin = calc_hash(type, content)
- if not self.exists(bin):
- self._write(bin, type, content)
- self.objcache.add(bin)
- return bin
+ self._require_objcache()
+ sha = calc_hash(type, content)
+ if not self.exists(sha):
+ self._write(sha, type, content)
+ self.objcache.add(sha)
+ return sha
def new_blob(self, blob):
"""Create a blob object in the pack with the supplied content."""
"""Remove the pack file from disk."""
f = self.file
if f:
+ self.idx = None
self.file = None
f.close()
os.unlink(self.filename + '.pack')
- def _end(self):
+ def _end(self, run_midx=True):
f = self.file
if not f: return None
self.file = None
self.objcache = None
+ idx = self.idx
+ self.idx = None
# update object count
f.seek(8)
# calculate the pack sha1sum
f.seek(0)
sum = Sha1()
- while 1:
- b = f.read(65536)
+ for b in chunkyreader(f):
sum.update(b)
- if not b: break
- f.write(sum.digest())
-
+ packbin = sum.digest()
+ f.write(packbin)
f.close()
- p = subprocess.Popen(['git', 'index-pack', '-v',
- '--index-version=2',
- self.filename + '.pack'],
- preexec_fn = _gitenv,
- stdout = subprocess.PIPE)
- out = p.stdout.read().strip()
- _git_wait('git index-pack', p)
- if not out:
- raise GitError('git index-pack produced no output')
- nameprefix = repo('objects/pack/%s' % out)
+ idx_f = open(self.filename + '.idx', 'wb')
+ obj_list_sha = self._write_pack_idx_v2(idx_f, idx, packbin)
+ idx_f.close()
+
+ nameprefix = repo('objects/pack/pack-%s' % obj_list_sha)
if os.path.exists(self.filename + '.map'):
os.unlink(self.filename + '.map')
os.rename(self.filename + '.pack', nameprefix + '.pack')
os.rename(self.filename + '.idx', nameprefix + '.idx')
- auto_midx(repo('objects/pack'))
+ if run_midx:
+ auto_midx(repo('objects/pack'))
return nameprefix
- def close(self):
+ def close(self, run_midx=True):
"""Close the pack file and move it to its definitive path."""
- return self._end()
+ return self._end(run_midx=run_midx)
+
+ def _write_pack_idx_v2(self, file, idx, packbin):
+ sum = Sha1()
+
+ def write(data):
+ file.write(data)
+ sum.update(data)
+
+ write('\377tOc\0\0\0\2')
+
+ n = 0
+ for part in idx:
+ n += len(part)
+ write(struct.pack('!i', n))
+ part.sort(key=lambda x: x[0])
+
+ obj_list_sum = Sha1()
+ for part in idx:
+ for entry in part:
+ write(entry[0])
+ obj_list_sum.update(entry[0])
+ for part in idx:
+ for entry in part:
+ write(struct.pack('!I', entry[1]))
+ ofs64_list = []
+ for part in idx:
+ for entry in part:
+ if entry[2] & 0x80000000:
+ write(struct.pack('!I', 0x80000000 | len(ofs64_list)))
+ ofs64_list.append(struct.pack('!Q', entry[2]))
+ else:
+ write(struct.pack('!i', entry[2]))
+ for ofs64 in ofs64_list:
+ write(ofs64)
+
+ write(packbin)
+ file.write(sum.digest())
+ return obj_list_sum.hexdigest()
def _git_date(date):
raise GitError, 'no such commit %r' % ref
+def rev_parse(committish):
+ """Resolve the full hash for 'committish', if it exists.
+
+ Should be roughly equivalent to 'git rev-parse'.
+
+ Returns the hex value of the hash if it is found, None if 'committish' does
+ not correspond to anything.
+ """
+ head = read_ref(committish)
+ if head:
+ debug2("resolved from ref: commit = %s\n" % head.encode('hex'))
+ return head
+
+ pL = PackIdxList(repo('objects/pack'))
+
+ if len(committish) == 40:
+ try:
+ hash = committish.decode('hex')
+ except TypeError:
+ return None
+
+ if pL.exists(hash):
+ return hash
+
+ return None
+
+
def update_ref(refname, newval, oldval):
"""Change the commit pointed to by a branch."""
if not oldval:
def init_repo(path=None):
"""Create the Git bare repository for bup in a given path."""
guess_repo(path)
- d = repo()
+ d = repo() # appends a / to the path
+ parent = os.path.dirname(os.path.dirname(d))
+ if parent and not os.path.exists(parent):
+ raise GitError('parent directory "%s" does not exist\n' % parent)
if os.path.exists(d) and not os.path.isdir(os.path.join(d, '.')):
raise GitError('"%d" exists but is not a directory\n' % d)
p = subprocess.Popen(['git', '--bare', 'init'], stdout=sys.stderr,
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
close_fds = True,
+ bufsize = 4096,
preexec_fn = _gitenv)
def _fast_get(self, id):
assert(not id.startswith('-'))
self.inprogress = id
self.p.stdin.write('%s\n' % id)
+ self.p.stdin.flush()
hdr = self.p.stdout.readline()
if hdr.endswith(' missing\n'):
self.inprogress = None
yield d
except StopIteration:
log('booger!\n')
+
+def tags():
+ """Return a dictionary of all tags in the form {hash: [tag_names, ...]}."""
+ tags = {}
+ for (n,c) in list_refs():
+ if n.startswith('refs/tags/'):
+ name = n[10:]
+ if not c in tags:
+ tags[c] = []
+
+ tags[c].append(name) # more than one tag can point at 'c'
+
+ return tags
projects / bup.git / blobdiff