view mercurial/formatter.py @ 30212:260af19891f2

changegroup: increase write buffer size to 128k

By default, Python defers to the operating system for choosing the
default buffer size on opened files. On my Linux machine, the default
is 4k, which is really small for 2016.

This patch bumps the write buffer size when writing
changegroups/bundles to 128k. This matches the 128k read buffer
we already use on revlogs.

It's worth noting that this only impacts when writing to an explicit
file (such as during `hg bundle`). Buffers when writing to bundle
files via the repo vfs or to a temporary file are not impacted.

When producing a none-v2 bundle file of the mozilla-unified repository,
this change caused the number of write() system calls to drop from
952,449 to 29,788. After this change, the most frequent system
calls are fstat(), read(), lseek(), and open(). There were
2,523,672 system calls after this patch (so a net decrease of
~950k is statistically significant).

This change shows no performance change on my system. But I have a
high-end system with a fast SSD. It is quite possible this change
will have a significant impact on network file systems, where
extra network round trips due to excessive I/O system calls could
introduce significant latency.

# 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.

from __future__ import absolute_import

import os

from .i18n import _
from .node import (
    hex,
    short,
)

from . import (
    encoding,
    error,
    templatekw,
    templater,
    util,
)

pickle = util.pickle

class _nullconverter(object):
    '''convert non-primitive data types to be processed by formatter'''
    @staticmethod
    def formatdate(date, fmt):
        '''convert date tuple to appropriate format'''
        return date
    @staticmethod
    def formatdict(data, key, value, fmt, sep):
        '''convert dict or key-value pairs to appropriate dict format'''
        # use plain dict instead of util.sortdict so that data can be
        # serialized as a builtin dict in pickle output
        return dict(data)
    @staticmethod
    def formatlist(data, name, fmt, sep):
        '''convert iterable to appropriate list format'''
        return list(data)

class baseformatter(object):
    def __init__(self, ui, topic, opts, converter):
        self._ui = ui
        self._topic = topic
        self._style = opts.get("style")
        self._template = opts.get("template")
        self._converter = converter
        self._item = None
        # function to convert node to string suitable for this output
        self.hexfunc = hex
    def __enter__(self):
        return self
    def __exit__(self, exctype, excvalue, traceback):
        if exctype is None:
            self.end()
    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 formatdate(self, date, fmt='%a %b %d %H:%M:%S %Y %1%2'):
        '''convert date tuple to appropriate format'''
        return self._converter.formatdate(date, fmt)
    def formatdict(self, data, key='key', value='value', fmt='%s=%s', sep=' '):
        '''convert dict or key-value pairs to appropriate dict format'''
        return self._converter.formatdict(data, key, value, fmt, sep)
    def formatlist(self, data, name, fmt='%s', sep=' '):
        '''convert iterable to appropriate list format'''
        # name is mandatory argument for now, but it could be optional if
        # we have default template keyword, e.g. {item}
        return self._converter.formatlist(data, name, fmt, sep)
    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'''
        fieldkeys = fields.split()
        assert len(fieldkeys) == len(fielddata)
        self._item.update(zip(fieldkeys, fielddata))
    def condwrite(self, cond, fields, deftext, *fielddata, **opts):
        '''do conditional write (primarily for plain formatter)'''
        fieldkeys = fields.split()
        assert len(fieldkeys) == len(fielddata)
        self._item.update(zip(fieldkeys, fielddata))
    def plain(self, text, **opts):
        '''show raw text for non-templated mode'''
        pass
    def isplain(self):
        '''check for plain formatter usage'''
        return False
    def nested(self, field):
        '''sub formatter to store nested data in the specified field'''
        self._item[field] = data = []
        return _nestedformatter(self._ui, self._converter, data)
    def end(self):
        '''end output for the formatter'''
        if self._item is not None:
            self._showitem()

class _nestedformatter(baseformatter):
    '''build sub items and store them in the parent formatter'''
    def __init__(self, ui, converter, data):
        baseformatter.__init__(self, ui, topic='', opts={}, converter=converter)
        self._data = data
    def _showitem(self):
        self._data.append(self._item)

def _iteritems(data):
    '''iterate key-value pairs in stable order'''
    if isinstance(data, dict):
        return sorted(data.iteritems())
    return data

class _plainconverter(object):
    '''convert non-primitive data types to text'''
    @staticmethod
    def formatdate(date, fmt):
        '''stringify date tuple in the given format'''
        return util.datestr(date, fmt)
    @staticmethod
    def formatdict(data, key, value, fmt, sep):
        '''stringify key-value pairs separated by sep'''
        return sep.join(fmt % (k, v) for k, v in _iteritems(data))
    @staticmethod
    def formatlist(data, name, fmt, sep):
        '''stringify iterable separated by sep'''
        return sep.join(fmt % e for e in data)

class plainformatter(baseformatter):
    '''the default text output scheme'''
    def __init__(self, ui, topic, opts):
        baseformatter.__init__(self, ui, topic, opts, _plainconverter)
        if ui.debugflag:
            self.hexfunc = hex
        else:
            self.hexfunc = short
    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 isplain(self):
        return True
    def nested(self, field):
        # nested data will be directly written to ui
        return self
    def end(self):
        pass

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

def _jsonifyobj(v):
    if isinstance(v, dict):
        xs = ['"%s": %s' % (encoding.jsonescape(k), _jsonifyobj(u))
              for k, u in sorted(v.iteritems())]
        return '{' + ', '.join(xs) + '}'
    elif isinstance(v, (list, 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, _nullconverter)
        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 _templateconverter(object):
    '''convert non-primitive data types to be processed by templater'''
    @staticmethod
    def formatdate(date, fmt):
        '''return date tuple'''
        return date
    @staticmethod
    def formatdict(data, key, value, fmt, sep):
        '''build object that can be evaluated as either plain string or dict'''
        data = util.sortdict(_iteritems(data))
        def f():
            yield _plainconverter.formatdict(data, key, value, fmt, sep)
        return templatekw._hybrid(f(), data, lambda k: {key: k, value: data[k]},
                                  lambda d: fmt % (d[key], d[value]))
    @staticmethod
    def formatlist(data, name, fmt, sep):
        '''build object that can be evaluated as either plain string or list'''
        data = list(data)
        def f():
            yield _plainconverter.formatlist(data, name, fmt, sep)
        return templatekw._hybrid(f(), data, lambda x: {name: x},
                                  lambda d: fmt % d[name])

class templateformatter(baseformatter):
    def __init__(self, ui, topic, opts):
        baseformatter.__init__(self, ui, topic, opts, _templateconverter)
        self._topic = topic
        self._t = gettemplater(ui, topic, opts.get('template', ''))
    def _showitem(self):
        g = self._t(self._topic, ui=self._ui, **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:
        return templater.unquotestring(t), None

    if tmpl == 'list':
        ui.write(_("available styles: %s\n") % templater.stylelist())
        raise error.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)
    assert not (tmpl and mapfile)
    if mapfile:
        return templater.templater.frommapfile(mapfile)
    return maketemplater(ui, topic, tmpl)

def maketemplater(ui, topic, tmpl, filters=None, cache=None):
    """Create a templater from a string template 'tmpl'"""
    aliases = ui.configitems('templatealias')
    t = templater.templater(filters=filters, cache=cache, aliases=aliases)
    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)
    # developer config: ui.formatdebug
    elif ui.configbool('ui', 'formatdebug'):
        return debugformatter(ui, topic, opts)
    # deprecated config: ui.formatjson
    elif ui.configbool('ui', 'formatjson'):
        return jsonformatter(ui, topic, opts)
    return plainformatter(ui, topic, opts)