3 from bup import _helpers, helpers
4 from bup.helpers import sc_page_size
6 _fmincore = getattr(helpers, 'fmincore', None)
8 BLOB_MAX = 8192*4 # 8192 is the "typical" blob size for bupsplit
9 BLOB_READ_SIZE = 1024*1024
11 progress_callback = None
14 GIT_MODE_FILE = 0100644
15 GIT_MODE_TREE = 040000
16 GIT_MODE_SYMLINK = 0120000
17 assert(GIT_MODE_TREE != 40000) # 0xxx should be treated as octal
19 # The purpose of this type of buffer is to avoid copying on peek(), get(),
20 # and eat(). We do copy the buffer contents on put(), but that should
21 # be ok if we always only put() large amounts of data at a time.
29 self.data = buffer(self.data, self.start) + s
32 def peek(self, count):
33 return buffer(self.data, self.start, count)
39 v = buffer(self.data, self.start, count)
44 return len(self.data) - self.start
47 def _fadvise_pages_done(fd, first_page, count):
48 assert(first_page >= 0)
51 _helpers.fadvise_done(fd,
52 first_page * sc_page_size,
56 def _nonresident_page_regions(status_bytes, incore_mask, max_region_len=None):
57 """Return (start_page, count) pairs in ascending start_page order for
58 each contiguous region of nonresident pages indicated by the
59 mincore() status_bytes. Limit the number of pages in each region
61 assert(max_region_len is None or max_region_len > 0)
63 for i, x in enumerate(status_bytes):
64 in_core = x & incore_mask
73 elif max_region_len and count >= max_region_len:
77 yield (start, len(status_bytes) - start)
80 def _uncache_ours_upto(fd, offset, first_region, remaining_regions):
81 """Uncache the pages of fd indicated by first_region and
82 remaining_regions that are before offset, where each region is a
83 (start_page, count) pair. The final region must have a start_page
85 rstart, rlen = first_region
86 while rstart is not None and (rstart + rlen) * sc_page_size <= offset:
87 _fadvise_pages_done(fd, rstart, rlen)
88 rstart, rlen = next(remaining_regions, (None, None))
92 def readfile_iter(files, progress=None):
93 for filenum,f in enumerate(files):
96 fd = rpr = rstart = rlen = None
97 if _fmincore and hasattr(f, 'fileno'):
99 max_chunk = max(1, (8 * 1024 * 1024) / sc_page_size)
100 rpr = _nonresident_page_regions(_fmincore(fd),
101 helpers.MINCORE_INCORE, max_chunk)
102 rstart, rlen = next(rpr, (None, None))
105 progress(filenum, len(b))
106 b = f.read(BLOB_READ_SIZE)
109 rstart, rlen = _uncache_ours_upto(fd, ofs, (rstart, rlen), rpr)
114 rstart, rlen = _uncache_ours_upto(fd, ofs, (rstart, rlen), rpr)
117 def _splitbuf(buf, basebits, fanbits):
119 b = buf.peek(buf.used())
120 (ofs, bits) = _helpers.splitbuf(b)
126 level = (bits-basebits)//fanbits # integer division
128 yield buffer(b, 0, ofs), level
131 while buf.used() >= BLOB_MAX:
132 # limit max blob size
133 yield buf.get(BLOB_MAX), 0
136 def _hashsplit_iter(files, progress):
137 assert(BLOB_READ_SIZE > BLOB_MAX)
138 basebits = _helpers.blobbits()
139 fanbits = int(math.log(fanout or 128, 2))
141 for inblock in readfile_iter(files, progress):
143 for buf_and_level in _splitbuf(buf, basebits, fanbits):
146 yield buf.get(buf.used()), 0
149 def _hashsplit_iter_keep_boundaries(files, progress):
150 for real_filenum,f in enumerate(files):
152 def prog(filenum, nbytes):
153 # the inner _hashsplit_iter doesn't know the real file count,
154 # so we'll replace it here.
155 return progress(real_filenum, nbytes)
158 for buf_and_level in _hashsplit_iter([f], progress=prog):
162 def hashsplit_iter(files, keep_boundaries, progress):
164 return _hashsplit_iter_keep_boundaries(files, progress)
166 return _hashsplit_iter(files, progress)
170 def split_to_blobs(makeblob, files, keep_boundaries, progress):
172 for (blob, level) in hashsplit_iter(files, keep_boundaries, progress):
174 total_split += len(blob)
175 if progress_callback:
176 progress_callback(len(blob))
177 yield (sha, len(blob), level)
180 def _make_shalist(l):
183 total = sum(size for mode,sha,size, in l)
184 vlen = len('%x' % total)
186 for (mode, sha, size) in l:
187 shalist.append((mode, '%0*x' % (vlen,ofs), sha))
190 return (shalist, total)
193 def _squish(maketree, stacks, n):
195 while i < n or len(stacks[i]) >= MAX_PER_TREE:
196 while len(stacks) <= i+1:
198 if len(stacks[i]) == 1:
199 stacks[i+1] += stacks[i]
201 (shalist, size) = _make_shalist(stacks[i])
202 tree = maketree(shalist)
203 stacks[i+1].append((GIT_MODE_TREE, tree, size))
208 def split_to_shalist(makeblob, maketree, files,
209 keep_boundaries, progress=None):
210 sl = split_to_blobs(makeblob, files, keep_boundaries, progress)
214 for (sha,size,level) in sl:
215 shal.append((GIT_MODE_FILE, sha, size))
216 return _make_shalist(shal)[0]
219 for (sha,size,level) in sl:
220 stacks[0].append((GIT_MODE_FILE, sha, size))
221 _squish(maketree, stacks, level)
222 #log('stacks: %r\n' % [len(i) for i in stacks])
223 _squish(maketree, stacks, len(stacks)-1)
224 #log('stacks: %r\n' % [len(i) for i in stacks])
225 return _make_shalist(stacks[-1])[0]
228 def split_to_blob_or_tree(makeblob, maketree, files,
229 keep_boundaries, progress=None):
230 shalist = list(split_to_shalist(makeblob, maketree,
231 files, keep_boundaries, progress))
232 if len(shalist) == 1:
233 return (shalist[0][0], shalist[0][2])
234 elif len(shalist) == 0:
235 return (GIT_MODE_FILE, makeblob(''))
237 return (GIT_MODE_TREE, maketree(shalist))
240 def open_noatime(name):
241 fd = _helpers.open_noatime(name)
243 return os.fdopen(fd, 'rb', 1024*1024)