sapling/eden/hg-server/edenscm/mercurial/dagparser.py
Durham Goode 98d9269874 server: copy hg to a new hg-server directory
Summary:
Create a fork of the Mercurial code that we can use to build server
rpms. The hg servers will continue to exist for a few more months while we move
the darkstorm and ediscovery use cases off them. In the mean time, we want to
start making breaking changes to the client, so let's create a stable copy of
the hg code to produce rpms for the hg servers.

The fork is based off c7770c78d, the latest hg release.

This copies the files as is, then adds some minor tweaks to get it to build:
- Disables some lint checks that appear to be bypassed by path
- sed replace eden/scm with eden/hg-server
- Removed a dependency on scm/telemetry from the edenfs-client tests since
  scm/telemetry pulls in the original eden/scm/lib/configparser which conflicts
  with the hg-server conflict parser.

allow-large-files

Reviewed By: quark-zju

Differential Revision: D27632557

fbshipit-source-id: b2f442f4ec000ea08e4d62de068750832198e1f4
2021-04-09 10:09:06 -07:00

643 lines
19 KiB
Python

# Portions Copyright (c) Facebook, Inc. and its affiliates.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2.
# dagparser.py - parser and generator for concise description of DAGs
#
# Copyright 2010 Peter Arrenbrecht <peter@arrenbrecht.ch>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import absolute_import
import re
import string
from bindings import vlq
from . import error, pycompat, util
from .i18n import _
from .pycompat import range
def parsedag(desc):
'''parses a DAG from a concise textual description; generates events
"+n" is a linear run of n nodes based on the current default parent
"." is a single node based on the current default parent
"$" resets the default parent to -1 (implied at the start);
otherwise the default parent is always the last node created
"<p" sets the default parent to the backref p
"*p" is a fork at parent p, where p is a backref
"*p1/p2/.../pn" is a merge of parents p1..pn, where the pi are backrefs
"/p2/.../pn" is a merge of the preceding node and p2..pn
":name" defines a label for the preceding node; labels can be redefined
"@text" emits an annotation event for text
"!command" emits an action event for the current node
"!!my command\n" is like "!", but to the end of the line
"#...\n" is a comment up to the end of the line
Whitespace between the above elements is ignored.
A backref is either
* a number n, which references the node curr-n, where curr is the current
node, or
* the name of a label you placed earlier using ":name", or
* empty to denote the default parent.
All string valued-elements are either strictly alphanumeric, or must
be enclosed in double quotes ("..."), with "\" as escape character.
Generates sequence of
('n', (id, [parentids])) for node creation
('l', (id, labelname)) for labels on nodes
('a', text) for annotations
('c', command) for actions (!)
('C', command) for line actions (!!)
Examples
--------
Example of a complex graph (output not shown for brevity):
>>> len(list(parsedag(b"""
...
... +3 # 3 nodes in linear run
... :forkhere # a label for the last of the 3 nodes from above
... +5 # 5 more nodes on one branch
... :mergethis # label again
... <forkhere # set default parent to labeled fork node
... +10 # 10 more nodes on a parallel branch
... @stable # following nodes will be annotated as "stable"
... +5 # 5 nodes in stable
... !addfile # custom command; could trigger new file in next node
... +2 # two more nodes
... /mergethis # merge last node with labeled node
... +4 # 4 more nodes descending from merge node
...
... """)))
34
Empty list:
>>> list(parsedag(b""))
[]
A simple linear run:
>>> list(parsedag(b"+3"))
[('n', (0, [-1])), ('n', (1, [0])), ('n', (2, [1]))]
Some non-standard ways to define such runs:
>>> list(parsedag(b"+1+2"))
[('n', (0, [-1])), ('n', (1, [0])), ('n', (2, [1]))]
>>> list(parsedag(b"+1*1*"))
[('n', (0, [-1])), ('n', (1, [0])), ('n', (2, [1]))]
>>> list(parsedag(b"*"))
[('n', (0, [-1]))]
>>> list(parsedag(b"..."))
[('n', (0, [-1])), ('n', (1, [0])), ('n', (2, [1]))]
A fork and a join, using numeric back references:
>>> list(parsedag(b"+2*2*/2"))
[('n', (0, [-1])), ('n', (1, [0])), ('n', (2, [0])), ('n', (3, [2, 1]))]
>>> list(parsedag(b"+2<2+1/2"))
[('n', (0, [-1])), ('n', (1, [0])), ('n', (2, [0])), ('n', (3, [2, 1]))]
Placing a label:
>>> list(parsedag(b"+1 :mylabel +1"))
[('n', (0, [-1])), ('l', (0, 'mylabel')), ('n', (1, [0]))]
An empty label (silly, really):
>>> list(parsedag(b"+1:+1"))
[('n', (0, [-1])), ('l', (0, '')), ('n', (1, [0]))]
Fork and join, but with labels instead of numeric back references:
>>> list(parsedag(b"+1:f +1:p2 *f */p2"))
[('n', (0, [-1])), ('l', (0, 'f')), ('n', (1, [0])), ('l', (1, 'p2')),
('n', (2, [0])), ('n', (3, [2, 1]))]
>>> list(parsedag(b"+1:f +1:p2 <f +1 /p2"))
[('n', (0, [-1])), ('l', (0, 'f')), ('n', (1, [0])), ('l', (1, 'p2')),
('n', (2, [0])), ('n', (3, [2, 1]))]
Restarting from the root:
>>> list(parsedag(b"+1 $ +1"))
[('n', (0, [-1])), ('n', (1, [-1]))]
Annotations, which are meant to introduce sticky state for subsequent nodes:
>>> list(parsedag(b"+1 @ann +1"))
[('n', (0, [-1])), ('a', 'ann'), ('n', (1, [0]))]
>>> list(parsedag(b'+1 @"my annotation" +1'))
[('n', (0, [-1])), ('a', 'my annotation'), ('n', (1, [0]))]
Commands, which are meant to operate on the most recently created node:
>>> list(parsedag(b"+1 !cmd +1"))
[('n', (0, [-1])), ('c', 'cmd'), ('n', (1, [0]))]
>>> list(parsedag(b'+1 !"my command" +1'))
[('n', (0, [-1])), ('c', 'my command'), ('n', (1, [0]))]
>>> list(parsedag(b'+1 !!my command line\\n +1'))
[('n', (0, [-1])), ('C', 'my command line'), ('n', (1, [0]))]
Comments, which extend to the end of the line:
>>> list(parsedag(b'+1 # comment\\n+1'))
[('n', (0, [-1])), ('n', (1, [0]))]
Error:
>>> try: list(parsedag(b'+1 bad'))
... except Exception as e: print(bytes(e))
invalid character in dag description: bad...
'''
if not desc:
return
wordchars = pycompat.bytestr(string.ascii_letters + string.digits)
labels = {}
p1 = -1
r = 0
def resolve(ref):
if not ref:
return p1
elif ref[0] in pycompat.bytestr(string.digits):
return r - int(ref)
else:
return labels[ref]
chiter = iter(desc)
def nextch():
return next(chiter, "\0")
def nextrun(c, allow):
s = ""
while c in allow:
s += c
c = nextch()
return c, s
def nextdelimited(c, limit, escape):
s = ""
while c != limit:
if c == escape:
c = nextch()
s += c
c = nextch()
return nextch(), s
def nextstring(c):
if c == '"':
return nextdelimited(nextch(), '"', "\\")
else:
return nextrun(c, wordchars)
c = nextch()
while c != "\0":
while c in pycompat.bytestr(string.whitespace):
c = nextch()
if c == ".":
yield "n", (r, [p1])
p1 = r
r += 1
c = nextch()
elif c == "+":
c, digs = nextrun(nextch(), pycompat.bytestr(string.digits))
n = int(digs)
for i in range(0, n):
yield "n", (r, [p1])
p1 = r
r += 1
elif c in "*/":
if c == "*":
c = nextch()
c, pref = nextstring(c)
prefs = [pref]
while c == "/":
c, pref = nextstring(nextch())
prefs.append(pref)
ps = [resolve(ref) for ref in prefs]
yield "n", (r, ps)
p1 = r
r += 1
elif c == "<":
c, ref = nextstring(nextch())
p1 = resolve(ref)
elif c == ":":
c, name = nextstring(nextch())
labels[name] = p1
yield "l", (p1, name)
elif c == "@":
c, text = nextstring(nextch())
yield "a", text
elif c == "!":
c = nextch()
if c == "!":
cmd = ""
c = nextch()
while c not in "\n\r\0":
cmd += c
c = nextch()
yield "C", cmd
else:
c, cmd = nextstring(c)
yield "c", cmd
elif c == "#":
while c not in "\n\r\0":
c = nextch()
elif c == "$":
p1 = -1
c = nextch()
elif c == "\0":
return # in case it was preceded by whitespace
else:
s = ""
i = 0
while c != "\0" and i < 10:
s += c
i += 1
c = nextch()
raise error.Abort(_("invalid character in dag description: " "%s...") % s)
def dagtextlines(
events,
addspaces=True,
wraplabels=False,
wrapannotations=False,
wrapcommands=False,
wrapnonlinear=False,
usedots=False,
maxlinewidth=70,
):
"""generates single lines for dagtext()"""
def wrapstring(text):
if re.match("^[0-9a-z]*$", text):
return text
return '"' + text.replace("\\", "\\\\").replace('"', '"') + '"'
def gen():
labels = {}
run = 0
wantr = 0
needroot = False
for kind, data in events:
if kind == "n":
r, ps = data
# sanity check
if r != wantr:
raise error.Abort(_("expected id %i, got %i") % (wantr, r))
if not ps:
ps = [-1]
else:
for p in ps:
if p >= r:
raise error.Abort(
_("parent id %i is larger than " "current id %i")
% (p, r)
)
wantr += 1
# new root?
p1 = r - 1
if len(ps) == 1 and ps[0] == -1:
if needroot:
if run:
yield "+%d" % run
run = 0
if wrapnonlinear:
yield "\n"
yield "$"
p1 = -1
else:
needroot = True
if len(ps) == 1 and ps[0] == p1:
if usedots:
yield "."
else:
run += 1
else:
if run:
yield "+%d" % run
run = 0
if wrapnonlinear:
yield "\n"
prefs = []
for p in ps:
if p == p1:
prefs.append("")
elif p in labels:
prefs.append(labels[p])
else:
prefs.append("%d" % (r - p))
yield "*" + "/".join(prefs)
else:
if run:
yield "+%d" % run
run = 0
if kind == "l":
rid, name = data
labels[rid] = name
yield ":" + name
if wraplabels:
yield "\n"
elif kind == "c":
yield "!" + wrapstring(data)
if wrapcommands:
yield "\n"
elif kind == "C":
yield "!!" + data
yield "\n"
elif kind == "a":
if wrapannotations:
yield "\n"
yield "@" + wrapstring(data)
elif kind == "#":
yield "#" + data
yield "\n"
else:
raise error.Abort(
_("invalid event type in dag: " "('%s', '%s')")
% (util.escapestr(kind), util.escapestr(data))
)
if run:
yield "+%d" % run
line = ""
for part in gen():
if part == "\n":
if line:
yield line
line = ""
else:
if len(line) + len(part) >= maxlinewidth:
yield line
line = ""
elif addspaces and line and part != ".":
line += " "
line += part
if line:
yield line
def dagtext(
dag,
addspaces=True,
wraplabels=False,
wrapannotations=False,
wrapcommands=False,
wrapnonlinear=False,
usedots=False,
maxlinewidth=70,
):
"""generates lines of a textual representation for a dag event stream
events should generate what parsedag() does, so:
('n', (id, [parentids])) for node creation
('l', (id, labelname)) for labels on nodes
('a', text) for annotations
('c', text) for commands
('C', text) for line commands ('!!')
('#', text) for comment lines
Parent nodes must come before child nodes.
Examples
--------
Linear run:
>>> dagtext([(b'n', (0, [-1])), (b'n', (1, [0]))])
'+2'
Two roots:
>>> dagtext([(b'n', (0, [-1])), (b'n', (1, [-1]))])
'+1 $ +1'
Fork and join:
>>> dagtext([(b'n', (0, [-1])), (b'n', (1, [0])), (b'n', (2, [0])),
... (b'n', (3, [2, 1]))])
'+2 *2 */2'
Fork and join with labels:
>>> dagtext([(b'n', (0, [-1])), (b'l', (0, b'f')), (b'n', (1, [0])),
... (b'l', (1, b'p2')), (b'n', (2, [0])), (b'n', (3, [2, 1]))])
'+1 :f +1 :p2 *f */p2'
Annotations:
>>> dagtext([(b'n', (0, [-1])), (b'a', b'ann'), (b'n', (1, [0]))])
'+1 @ann +1'
>>> dagtext([(b'n', (0, [-1])),
... (b'a', b'my annotation'),
... (b'n', (1, [0]))])
'+1 @"my annotation" +1'
Commands:
>>> dagtext([(b'n', (0, [-1])), (b'c', b'cmd'), (b'n', (1, [0]))])
'+1 !cmd +1'
>>> dagtext([(b'n', (0, [-1])),
... (b'c', b'my command'),
... (b'n', (1, [0]))])
'+1 !"my command" +1'
>>> dagtext([(b'n', (0, [-1])),
... (b'C', b'my command line'),
... (b'n', (1, [0]))])
'+1 !!my command line\\n+1'
Comments:
>>> dagtext([(b'n', (0, [-1])), (b'#', b' comment'), (b'n', (1, [0]))])
'+1 # comment\\n+1'
>>> dagtext([])
''
Combining parsedag and dagtext:
>>> dagtext(parsedag(b'+1 :f +1 :p2 *f */p2'))
'+1 :f +1 :p2 *f */p2'
"""
return "\n".join(
dagtextlines(
dag,
addspaces,
wraplabels,
wrapannotations,
wrapcommands,
wrapnonlinear,
usedots,
maxlinewidth,
)
)
def bindag(revs, parentrevs):
"""Generate binary representation for a dag
revs is a list of commit identities. It must be topo-sorted from the oldest
to the newest commits.
parentrevs is a function that takes a commit identity, and returns a list
of parent commit identities: (rev) -> [rev].
The binary format consists of a stream of VLQ-encoded integers.
Every commit has an ID. The first commit created has ID K, the second has
ID K+1, and so on. K does not matter, because the format uses relative
reference to previous commits.
To parse the binary data, read integers one by one, and handle them using
the following rules:
- 0: New root commit.
Create a new commit that has no parents.
- 1: New single-parent commit.
Read the next integer as P. Create a new commit with a single parent
with ID = <last ID> - P.
- 2: New merge commit.
Read the next two integers as P, Q. Create a new commit with two
parents <last ID> - P, and <last ID> - Q.
- 3: New merge commit (fast path 1).
Read the next integer as Q. Create a new commit with two parents:
<last ID>, and <last ID> - Q.
- 4: New merge commit (fast path 2).
Read the next integer as P. Create a new commit with two parents:
<last ID> - P, and <last ID>.
- N: New linear stack of commits (N > 4).
Create a stack of N - 4 commits on top of the last commit created.
"""
idmap = {} # {rev: commit id}
buf = util.stringio()
def push(value, encode=vlq.encode, write=buf.write):
"""Append an integer to the buffer"""
write(encode(value))
pendingcommits = [0]
def pushpending(push=push):
if pendingcommits[0] > 0:
push(pendingcommits[0] + 4)
pendingcommits[0] = 0
for rev in revs:
nextid = len(idmap)
idmap[rev] = nextid
p1, p2 = parentrevs(rev)
if p1 == -1:
assert p2 == -1
pushpending()
push(0)
pendingcommits[0] = 0
elif idmap[p1] + 1 == nextid and p2 == -1:
pendingcommits[0] += 1
else:
pushpending()
lastid = nextid - 1
dp1 = lastid - idmap[p1]
if p2 == -1:
push(1)
push(dp1)
else:
dp2 = lastid - idmap[p2]
if dp1 == 0:
push(3)
push(dp2)
elif dp2 == 0:
push(4)
push(dp1)
else:
push(2)
push(dp1)
push(dp2)
pushpending()
return buf.getvalue()
def parsebindag(data):
"""Reverse of `bindag`. Translated binary DAG to revs and parentrevs.
The returned revs use integer commit identities starting from 0.
"""
def readiter(data, decodeat=vlq.decodeat):
offset = 0
while offset < len(data):
value, size = decodeat(data, offset)
yield value
offset += size
it = readiter(data)
parents = [] # index: id, value: parentids
append = parents.append
# build dag in-memory
while True:
i = next(it, None)
lastid = len(parents) - 1
if i is None:
break
elif i == 0:
append(())
elif i == 1:
p1 = lastid - next(it)
append((p1,))
elif i == 2:
p1 = lastid - next(it)
p2 = lastid - next(it)
append((p1, p2))
elif i == 3:
p1 = lastid
p2 = lastid - next(it)
append((p1, p2))
elif i == 4:
p1 = lastid - next(it)
p2 = lastid
append((p1, p2))
else:
n = i - 4
while n > 0:
p1 = len(parents) - 1
parents.append((p1,))
n -= 1
revs = range(len(parents))
parentrevs = parents.__getitem__
return revs, parentrevs