mdiff.py
131 lines
| 3.5 KiB
| text/x-python
|
PythonLexer
/ mercurial / mdiff.py
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r0 | #!/usr/bin/python | ||
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r71 | import difflib, struct, mmap | ||
devzero = file("/dev/zero") | ||||
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r0 | |||
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r64 | def unidiff(a, ad, b, bd, fn): | ||
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r35 | if not a and not b: return "" | ||
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r0 | a = a.splitlines(1) | ||
b = b.splitlines(1) | ||||
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r64 | l = list(difflib.unified_diff(a, b, "a/" + fn, "b/" + fn, ad, bd)) | ||
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r0 | return "".join(l) | ||
def textdiff(a, b): | ||||
return diff(a.splitlines(1), b.splitlines(1)) | ||||
def sortdiff(a, b): | ||||
la = lb = 0 | ||||
while 1: | ||||
if la >= len(a) or lb >= len(b): break | ||||
if b[lb] < a[la]: | ||||
si = lb | ||||
while lb < len(b) and b[lb] < a[la] : lb += 1 | ||||
yield "insert", la, la, si, lb | ||||
elif a[la] < b[lb]: | ||||
si = la | ||||
while la < len(a) and a[la] < b[lb]: la += 1 | ||||
yield "delete", si, la, lb, lb | ||||
else: | ||||
la += 1 | ||||
lb += 1 | ||||
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r64 | if lb < len(b): | ||
yield "insert", la, la, lb, len(b) | ||||
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r0 | |||
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r64 | if la < len(a): | ||
yield "delete", la, len(a), lb, lb | ||||
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r0 | |||
def diff(a, b, sorted=0): | ||||
bin = [] | ||||
p = [0] | ||||
for i in a: p.append(p[-1] + len(i)) | ||||
if sorted: | ||||
d = sortdiff(a, b) | ||||
else: | ||||
d = difflib.SequenceMatcher(None, a, b).get_opcodes() | ||||
for o, m, n, s, t in d: | ||||
if o == 'equal': continue | ||||
s = "".join(b[s:t]) | ||||
bin.append(struct.pack(">lll", p[m], p[n], len(s)) + s) | ||||
return "".join(bin) | ||||
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r71 | # This attempts to apply a series of patches in time proportional to | ||
# the total size of the patches, rather than patches * len(text). This | ||||
# means rather than shuffling strings around, we shuffle around | ||||
# pointers to fragments with fragment lists. | ||||
# | ||||
# When the fragment lists get too long, we collapse them. To do this | ||||
# efficiently, we do all our operations inside a buffer created by | ||||
# mmap and simply use memmove. This avoids creating a bunch of large | ||||
# temporary string buffers. | ||||
def patches(a, bins): | ||||
if not bins: return a | ||||
plens = [len(x) for x in bins] | ||||
pl = sum(plens) | ||||
bl = len(a) + pl | ||||
tl = bl + bl + pl # enough for the patches and two working texts | ||||
b1, b2 = 0, bl | ||||
m = mmap.mmap(devzero.fileno(), tl, mmap.MAP_PRIVATE) | ||||
# load our original text | ||||
m.write(a) | ||||
frags = [(len(a), b1)] | ||||
# copy all the patches into our segment so we can memmove from them | ||||
pos = b2 + bl | ||||
m.seek(pos) | ||||
for p in bins: m.write(p) | ||||
def pull(dst, src, l): # pull l bytes from src | ||||
while l: | ||||
f = src.pop(0) | ||||
if f[0] > l: # do we need to split? | ||||
src.insert(0, (f[0] - l, f[1] + l)) | ||||
dst.append((l, f[1])) | ||||
return | ||||
dst.append(f) | ||||
l -= f[0] | ||||
def collect(buf, list): | ||||
start = buf | ||||
for l, p in list: | ||||
m.move(buf, p, l) | ||||
buf += l | ||||
return (buf - start, start) | ||||
for plen in plens: | ||||
# if our list gets too long, execute it | ||||
if len(frags) > 128: | ||||
b2, b1 = b1, b2 | ||||
frags = [collect(b1, frags)] | ||||
new = [] | ||||
end = pos + plen | ||||
last = 0 | ||||
while pos < end: | ||||
p1, p2, l = struct.unpack(">lll", m[pos:pos + 12]) | ||||
pull(new, frags, p1 - last) # what didn't change | ||||
pull([], frags, p2 - p1) # what got deleted | ||||
new.append((l, pos + 12)) # what got added | ||||
pos += l + 12 | ||||
last = p2 | ||||
frags = new + frags # what was left at the end | ||||
t = collect(b2, frags) | ||||
return m[t[1]:t[1] + t[0]] | ||||
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r0 | def patch(a, bin): | ||
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r72 | return patches(a, [bin]) | ||
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r0 | |||
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r72 | try: | ||
import mpatch | ||||
patches = mpatch.patches | ||||
except: | ||||
pass | ||||