wireprotov2: define and implement "changesetdata" command
This commit introduces the "changesetdata" wire protocol command.
The role of the command is to expose data associated with changelog
revisions, including the raw revision data itself.
This command is the first piece of a new clone/pull strategy that
is built on top of domain-specific commands for data retrieval.
Instead of a monolithic "getbundle" command that transfers all of the
things, we'll be introducing commands for fetching specific pieces
of data.
Since the changeset is the fundamental unit from which we derive
pointers to other data (manifests, file nodes, etc), it makes sense
to start reimplementing pull with this data.
The command accepts as arguments a set of root and head revisions
defining the changesets that should be fetched as well as an explicit
list of nodes. By default, the command returns only the node values:
the client must explicitly request additional fields be added to the
response. Current supported fields are the list of parent nodes and
the revision fulltext.
My plan is to eventually add support for transferring other data
associated with changesets, including phases, bookmarks, obsolescence
markers, etc. Since the response format is CBOR, we'll be able to add
this data into the response object relatively easily (it should be
as simple as adding a key in a map).
The documentation captures a number of TODO items. Some of these may
require BC breaking changes. That's fine: wire protocol v2 is still
highly experimental.
Differential Revision: https://phab.mercurial-scm.org/D4481
# filesetlang.py - parser, tokenizer and utility for file set language
#
# Copyright 2010 Matt Mackall <mpm@selenic.com>
#
# 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
from .i18n import _
from . import (
error,
parser,
pycompat,
)
# common weight constants for static optimization
# (see registrar.filesetpredicate for details)
WEIGHT_CHECK_FILENAME = 0.5
WEIGHT_READ_CONTENTS = 30
WEIGHT_STATUS = 10
WEIGHT_STATUS_THOROUGH = 50
elements = {
# token-type: binding-strength, primary, prefix, infix, suffix
"(": (20, None, ("group", 1, ")"), ("func", 1, ")"), None),
":": (15, None, None, ("kindpat", 15), None),
"-": (5, None, ("negate", 19), ("minus", 5), None),
"not": (10, None, ("not", 10), None, None),
"!": (10, None, ("not", 10), None, None),
"and": (5, None, None, ("and", 5), None),
"&": (5, None, None, ("and", 5), None),
"or": (4, None, None, ("or", 4), None),
"|": (4, None, None, ("or", 4), None),
"+": (4, None, None, ("or", 4), None),
",": (2, None, None, ("list", 2), None),
")": (0, None, None, None, None),
"symbol": (0, "symbol", None, None, None),
"string": (0, "string", None, None, None),
"end": (0, None, None, None, None),
}
keywords = {'and', 'or', 'not'}
symbols = {}
globchars = ".*{}[]?/\\_"
def tokenize(program):
pos, l = 0, len(program)
program = pycompat.bytestr(program)
while pos < l:
c = program[pos]
if c.isspace(): # skip inter-token whitespace
pass
elif c in "(),-:|&+!": # handle simple operators
yield (c, None, pos)
elif (c in '"\'' or c == 'r' and
program[pos:pos + 2] in ("r'", 'r"')): # handle quoted strings
if c == 'r':
pos += 1
c = program[pos]
decode = lambda x: x
else:
decode = parser.unescapestr
pos += 1
s = pos
while pos < l: # find closing quote
d = program[pos]
if d == '\\': # skip over escaped characters
pos += 2
continue
if d == c:
yield ('string', decode(program[s:pos]), s)
break
pos += 1
else:
raise error.ParseError(_("unterminated string"), s)
elif c.isalnum() or c in globchars or ord(c) > 127:
# gather up a symbol/keyword
s = pos
pos += 1
while pos < l: # find end of symbol
d = program[pos]
if not (d.isalnum() or d in globchars or ord(d) > 127):
break
pos += 1
sym = program[s:pos]
if sym in keywords: # operator keywords
yield (sym, None, s)
else:
yield ('symbol', sym, s)
pos -= 1
else:
raise error.ParseError(_("syntax error"), pos)
pos += 1
yield ('end', None, pos)
def parse(expr):
p = parser.parser(elements)
tree, pos = p.parse(tokenize(expr))
if pos != len(expr):
raise error.ParseError(_("invalid token"), pos)
return parser.simplifyinfixops(tree, {'list', 'or'})
def getsymbol(x):
if x and x[0] == 'symbol':
return x[1]
raise error.ParseError(_('not a symbol'))
def getstring(x, err):
if x and (x[0] == 'string' or x[0] == 'symbol'):
return x[1]
raise error.ParseError(err)
def getkindpat(x, y, allkinds, err):
kind = getsymbol(x)
pat = getstring(y, err)
if kind not in allkinds:
raise error.ParseError(_("invalid pattern kind: %s") % kind)
return '%s:%s' % (kind, pat)
def getpattern(x, allkinds, err):
if x and x[0] == 'kindpat':
return getkindpat(x[1], x[2], allkinds, err)
return getstring(x, err)
def getlist(x):
if not x:
return []
if x[0] == 'list':
return list(x[1:])
return [x]
def getargs(x, min, max, err):
l = getlist(x)
if len(l) < min or len(l) > max:
raise error.ParseError(err)
return l
def _analyze(x):
if x is None:
return x
op = x[0]
if op in {'string', 'symbol'}:
return x
if op == 'kindpat':
getsymbol(x[1]) # kind must be a symbol
t = _analyze(x[2])
return (op, x[1], t)
if op == 'group':
return _analyze(x[1])
if op == 'negate':
raise error.ParseError(_("can't use negate operator in this context"))
if op == 'not':
t = _analyze(x[1])
return (op, t)
if op == 'and':
ta = _analyze(x[1])
tb = _analyze(x[2])
return (op, ta, tb)
if op == 'minus':
return _analyze(('and', x[1], ('not', x[2])))
if op in {'list', 'or'}:
ts = tuple(_analyze(y) for y in x[1:])
return (op,) + ts
if op == 'func':
getsymbol(x[1]) # function name must be a symbol
ta = _analyze(x[2])
return (op, x[1], ta)
raise error.ProgrammingError('invalid operator %r' % op)
def _insertstatushints(x):
"""Insert hint nodes where status should be calculated (first path)
This works in bottom-up way, summing up status names and inserting hint
nodes at 'and' and 'or' as needed. Thus redundant hint nodes may be left.
Returns (status-names, new-tree) at the given subtree, where status-names
is a sum of status names referenced in the given subtree.
"""
if x is None:
return (), x
op = x[0]
if op in {'string', 'symbol', 'kindpat'}:
return (), x
if op == 'not':
h, t = _insertstatushints(x[1])
return h, (op, t)
if op == 'and':
ha, ta = _insertstatushints(x[1])
hb, tb = _insertstatushints(x[2])
hr = ha + hb
if ha and hb:
return hr, ('withstatus', (op, ta, tb), ('string', ' '.join(hr)))
return hr, (op, ta, tb)
if op == 'or':
hs, ts = zip(*(_insertstatushints(y) for y in x[1:]))
hr = sum(hs, ())
if sum(bool(h) for h in hs) > 1:
return hr, ('withstatus', (op,) + ts, ('string', ' '.join(hr)))
return hr, (op,) + ts
if op == 'list':
hs, ts = zip(*(_insertstatushints(y) for y in x[1:]))
return sum(hs, ()), (op,) + ts
if op == 'func':
f = getsymbol(x[1])
# don't propagate 'ha' crossing a function boundary
ha, ta = _insertstatushints(x[2])
if getattr(symbols.get(f), '_callstatus', False):
return (f,), ('withstatus', (op, x[1], ta), ('string', f))
return (), (op, x[1], ta)
raise error.ProgrammingError('invalid operator %r' % op)
def _mergestatushints(x, instatus):
"""Remove redundant status hint nodes (second path)
This is the top-down path to eliminate inner hint nodes.
"""
if x is None:
return x
op = x[0]
if op == 'withstatus':
if instatus:
# drop redundant hint node
return _mergestatushints(x[1], instatus)
t = _mergestatushints(x[1], instatus=True)
return (op, t, x[2])
if op in {'string', 'symbol', 'kindpat'}:
return x
if op == 'not':
t = _mergestatushints(x[1], instatus)
return (op, t)
if op == 'and':
ta = _mergestatushints(x[1], instatus)
tb = _mergestatushints(x[2], instatus)
return (op, ta, tb)
if op in {'list', 'or'}:
ts = tuple(_mergestatushints(y, instatus) for y in x[1:])
return (op,) + ts
if op == 'func':
# don't propagate 'instatus' crossing a function boundary
ta = _mergestatushints(x[2], instatus=False)
return (op, x[1], ta)
raise error.ProgrammingError('invalid operator %r' % op)
def analyze(x):
"""Transform raw parsed tree to evaluatable tree which can be fed to
optimize() or getmatch()
All pseudo operations should be mapped to real operations or functions
defined in methods or symbols table respectively.
"""
t = _analyze(x)
_h, t = _insertstatushints(t)
return _mergestatushints(t, instatus=False)
def _optimizeandops(op, ta, tb):
if tb is not None and tb[0] == 'not':
return ('minus', ta, tb[1])
return (op, ta, tb)
def _optimizeunion(xs):
# collect string patterns so they can be compiled into a single regexp
ws, ts, ss = [], [], []
for x in xs:
w, t = _optimize(x)
if t is not None and t[0] in {'string', 'symbol', 'kindpat'}:
ss.append(t)
continue
ws.append(w)
ts.append(t)
if ss:
ws.append(WEIGHT_CHECK_FILENAME)
ts.append(('patterns',) + tuple(ss))
return ws, ts
def _optimize(x):
if x is None:
return 0, x
op = x[0]
if op == 'withstatus':
w, t = _optimize(x[1])
return w, (op, t, x[2])
if op in {'string', 'symbol'}:
return WEIGHT_CHECK_FILENAME, x
if op == 'kindpat':
w, t = _optimize(x[2])
return w, (op, x[1], t)
if op == 'not':
w, t = _optimize(x[1])
return w, (op, t)
if op == 'and':
wa, ta = _optimize(x[1])
wb, tb = _optimize(x[2])
if wa <= wb:
return wa, _optimizeandops(op, ta, tb)
else:
return wb, _optimizeandops(op, tb, ta)
if op == 'or':
ws, ts = _optimizeunion(x[1:])
if len(ts) == 1:
return ws[0], ts[0] # 'or' operation is fully optimized out
ts = tuple(it[1] for it in sorted(enumerate(ts),
key=lambda it: ws[it[0]]))
return max(ws), (op,) + ts
if op == 'list':
ws, ts = zip(*(_optimize(y) for y in x[1:]))
return sum(ws), (op,) + ts
if op == 'func':
f = getsymbol(x[1])
w = getattr(symbols.get(f), '_weight', 1)
wa, ta = _optimize(x[2])
return w + wa, (op, x[1], ta)
raise error.ProgrammingError('invalid operator %r' % op)
def optimize(x):
"""Reorder/rewrite evaluatable tree for optimization
All pseudo operations should be transformed beforehand.
"""
_w, t = _optimize(x)
return t
def prettyformat(tree):
return parser.prettyformat(tree, ('string', 'symbol'))