view mercurial/formatter.py @ 25708:d3d32643c060

wireproto: correctly escape batched args and responses (issue4739)

This issue appears to be as old as wireproto batching itself: I can
reproduce the failure as far back as 08ef6b5f3715 trivially by
rebasing the test changes in this patch, which was back in the 1.9
era. I didn't test before that change, because prior to that the
testfile has a different name and I'm lazy.

Note that the test thought it was checking this case, but it actually
wasn't: it put a literal ; in the arg and response for its greet
command, but the mangle/unmangle step defined in the test meant that
instead of "Fo, =;o" going over the wire, "Gp-!><p" went instead,
which doesn't contain any special characters (those being [.=;]) and
thus not exercising the escaping. The test has been updated to use
pre-unmangled special characters, so the request is now "Fo+<:o",
which mangles to "Gp,=;p". I have confirmed that the test fails
without the adjustment to the escaping rules in wireproto.py.

No existing clients of RPC batching were depending on the old behavior
in any way. The only *actual* users of batchable RPCs in core were:

1) largefiles, wherein it batches up many statlfile calls. It sends
hexlified hashes over the wire and gets a 0, 1, or 2 back as a
response. No risk of special characters.

2) setdiscovery, which was using heads() and known(), both of which
communicate via hexlified nodes. Again, no risk of special characters.

Since the escaping functionality has been completely broken since it
was introduced, we know that it has no users. As such, we can change
the escaping mechanism without having to worry about backwards
compatibility issues.

For the curious, this was detected by chance: it happens that the
lz4-compressed text of a test file for remotefilelog compressed to
something containing a ;, which then caused the failure when I moved
remotefilelog to using batching for file content fetching.

# formatter.py - generic output formatting for mercurial
#
# Copyright 2012 Matt Mackall <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

import cPickle
from node import hex, short
from i18n import _
import encoding, util
import templater
import os

class baseformatter(object):
    def __init__(self, ui, topic, opts):
        self._ui = ui
        self._topic = topic
        self._style = opts.get("style")
        self._template = opts.get("template")
        self._item = None
        # function to convert node to string suitable for this output
        self.hexfunc = hex
    def __nonzero__(self):
        '''return False if we're not doing real templating so we can
        skip extra work'''
        return True
    def _showitem(self):
        '''show a formatted item once all data is collected'''
        pass
    def startitem(self):
        '''begin an item in the format list'''
        if self._item is not None:
            self._showitem()
        self._item = {}
    def data(self, **data):
        '''insert data into item that's not shown in default output'''
        self._item.update(data)
    def write(self, fields, deftext, *fielddata, **opts):
        '''do default text output while assigning data to item'''
        for k, v in zip(fields.split(), fielddata):
            self._item[k] = v
    def condwrite(self, cond, fields, deftext, *fielddata, **opts):
        '''do conditional write (primarily for plain formatter)'''
        for k, v in zip(fields.split(), fielddata):
            self._item[k] = v
    def plain(self, text, **opts):
        '''show raw text for non-templated mode'''
        pass
    def end(self):
        '''end output for the formatter'''
        if self._item is not None:
            self._showitem()

class plainformatter(baseformatter):
    '''the default text output scheme'''
    def __init__(self, ui, topic, opts):
        baseformatter.__init__(self, ui, topic, opts)
        if ui.debugflag:
            self.hexfunc = hex
        else:
            self.hexfunc = short
    def __nonzero__(self):
        return False
    def startitem(self):
        pass
    def data(self, **data):
        pass
    def write(self, fields, deftext, *fielddata, **opts):
        self._ui.write(deftext % fielddata, **opts)
    def condwrite(self, cond, fields, deftext, *fielddata, **opts):
        '''do conditional write'''
        if cond:
            self._ui.write(deftext % fielddata, **opts)
    def plain(self, text, **opts):
        self._ui.write(text, **opts)
    def end(self):
        pass

class debugformatter(baseformatter):
    def __init__(self, ui, topic, opts):
        baseformatter.__init__(self, ui, topic, opts)
        self._ui.write("%s = [\n" % self._topic)
    def _showitem(self):
        self._ui.write("    " + repr(self._item) + ",\n")
    def end(self):
        baseformatter.end(self)
        self._ui.write("]\n")

class pickleformatter(baseformatter):
    def __init__(self, ui, topic, opts):
        baseformatter.__init__(self, ui, topic, opts)
        self._data = []
    def _showitem(self):
        self._data.append(self._item)
    def end(self):
        baseformatter.end(self)
        self._ui.write(cPickle.dumps(self._data))

def _jsonifyobj(v):
    if isinstance(v, tuple):
        return '[' + ', '.join(_jsonifyobj(e) for e in v) + ']'
    elif v is None:
        return 'null'
    elif v is True:
        return 'true'
    elif v is False:
        return 'false'
    elif isinstance(v, (int, float)):
        return str(v)
    else:
        return '"%s"' % encoding.jsonescape(v)

class jsonformatter(baseformatter):
    def __init__(self, ui, topic, opts):
        baseformatter.__init__(self, ui, topic, opts)
        self._ui.write("[")
        self._ui._first = True
    def _showitem(self):
        if self._ui._first:
            self._ui._first = False
        else:
            self._ui.write(",")

        self._ui.write("\n {\n")
        first = True
        for k, v in sorted(self._item.items()):
            if first:
                first = False
            else:
                self._ui.write(",\n")
            self._ui.write('  "%s": %s' % (k, _jsonifyobj(v)))
        self._ui.write("\n }")
    def end(self):
        baseformatter.end(self)
        self._ui.write("\n]\n")

class templateformatter(baseformatter):
    def __init__(self, ui, topic, opts):
        baseformatter.__init__(self, ui, topic, opts)
        self._topic = topic
        self._t = gettemplater(ui, topic, opts.get('template', ''))
    def _showitem(self):
        g = self._t(self._topic, **self._item)
        self._ui.write(templater.stringify(g))

def lookuptemplate(ui, topic, tmpl):
    # looks like a literal template?
    if '{' in tmpl:
        return tmpl, None

    # perhaps a stock style?
    if not os.path.split(tmpl)[0]:
        mapname = (templater.templatepath('map-cmdline.' + tmpl)
                   or templater.templatepath(tmpl))
        if mapname and os.path.isfile(mapname):
            return None, mapname

    # perhaps it's a reference to [templates]
    t = ui.config('templates', tmpl)
    if t:
        try:
            tmpl = templater.unquotestring(t)
        except SyntaxError:
            tmpl = t
        return tmpl, None

    if tmpl == 'list':
        ui.write(_("available styles: %s\n") % templater.stylelist())
        raise util.Abort(_("specify a template"))

    # perhaps it's a path to a map or a template
    if ('/' in tmpl or '\\' in tmpl) and os.path.isfile(tmpl):
        # is it a mapfile for a style?
        if os.path.basename(tmpl).startswith("map-"):
            return None, os.path.realpath(tmpl)
        tmpl = open(tmpl).read()
        return tmpl, None

    # constant string?
    return tmpl, None

def gettemplater(ui, topic, spec):
    tmpl, mapfile = lookuptemplate(ui, topic, spec)
    t = templater.templater(mapfile, {})
    if tmpl:
        t.cache[topic] = tmpl
    return t

def formatter(ui, topic, opts):
    template = opts.get("template", "")
    if template == "json":
        return jsonformatter(ui, topic, opts)
    elif template == "pickle":
        return pickleformatter(ui, topic, opts)
    elif template == "debug":
        return debugformatter(ui, topic, opts)
    elif template != "":
        return templateformatter(ui, topic, opts)
    elif ui.configbool('ui', 'formatdebug'):
        return debugformatter(ui, topic, opts)
    elif ui.configbool('ui', 'formatjson'):
        return jsonformatter(ui, topic, opts)
    return plainformatter(ui, topic, opts)