contrib/bash_completion

bundle2: increase payload part chunk size to 32kb

Bundle2 payload parts are framed chunks. Esentially, we obtain
data in equal size chunks of size `preferedchunksize` and emit those
to a generator. That generator is fed into a compressor (which can
be the no-op compressor, which just re-emits the generator). And
the output from the compressor likely goes to a file descriptor
or socket.

What this means is that small chunk sizes create more Python objects
and Python function calls than larger chunk sizes. And as we know,
Python object and function call overhead in performance sensitive
code matters (at least with CPython).

This commit increases the bundle2 part payload chunk size from 4k
to 32k. Practically speaking, this means that the chunks we feed
into a compressor (implemented in C code) or feed directly into a
file handle or socket write() are larger. It's possible the chunks
might be larger than what the receiver can handle in one logical
operation. But at that point, we're in C code, which is much more
efficient at dealing with splitting up the chunk and making multiple
function calls than Python is.

A downside to larger chunks is that the receiver has to wait for that
much data to arrive (either raw or from a decompressor) before it
can process the chunk. But 32kb still feels like a small buffer to
have to wait for. And in many cases, the client will convert from
8 read(4096) to 1 read(32768). That's happening in Python land. So
we cut down on the number of Python objects and function calls,
making the client faster as well. I don't think there are any
significant concerns to increasing the payload chunk size to 32kb.

The impact of this change on performance significant. Using `curl`
to obtain a stream clone bundle2 payload from a server on localhost
serving the mozilla-unified repository:

before: 20.78 user; 7.71 system;  80.5 MB/s
after:  13.90 user; 3.51 system; 132 MB/s
legacy:  9.72 user; 8.16 system; 132 MB/s

bundle2 stream clone generation is still more resource intensive than
legacy stream clone (that's likely because of the use of a
util.chunkbuffer). But the throughput is the same. We might
be in territory we're this is effectively a benchmark of the
networking stack or Python's syscall throughput.

From the client perspective, `hg clone -U --stream`:

before: 33.50 user; 7.95 system; 53.3 MB/s
after:  22.82 user; 7.33 system; 72.7 MB/s
legacy: 29.96 user; 7.94 system; 58.0 MB/s

And for `hg clone --stream` with a working directory update of
~230k files:

after:  119.55 user; 26.47 system; 0:57.08 wall
legacy: 126.98 user; 26.94 system; 1:05.56 wall

So, it appears that bundle2's stream clone is now definitively faster
than legacy stream clone!

Differential Revision: https://phab.mercurial-scm.org/D1932

# bash completion for the Mercurial distributed SCM -*- sh -*-

# Docs:
#
# If you source this file from your .bashrc, bash should be able to
# complete a command line that uses hg with all the available commands
# and options and sometimes even arguments.
#
# Mercurial allows you to define additional commands through extensions.
# Bash should be able to automatically figure out the name of these new
# commands and their options.  See below for how to define _hg_opt_foo
# and _hg_cmd_foo functions to fine-tune the completion for option and
# non-option arguments, respectively.
#
#
# Notes about completion for specific commands:
#
# - the completion function for the email command from the patchbomb
#   extension will try to call _hg_emails to get a list of e-mail
#   addresses.  It's up to the user to define this function.  For
#   example, put the addresses of the lists that you usually patchbomb
#   in ~/.patchbomb-to and the addresses that you usually use to send
#   the patchbombs in ~/.patchbomb-from and use something like this:
#
#      _hg_emails()
#      {
#          if [ -r ~/.patchbomb-$1 ]; then
#              cat ~/.patchbomb-$1
#          fi
#      }
#
#
# Writing completion functions for additional commands:
#
# If it exists, the function _hg_cmd_foo will be called without
# arguments to generate the completion candidates for the hg command
# "foo".  If the command receives some arguments that aren't options
# even though they start with a "-", you can define a function called
# _hg_opt_foo to generate the completion candidates.  If _hg_opt_foo
# doesn't return 0, regular completion for options is attempted.
#
# In addition to the regular completion variables provided by bash,
# the following variables are also set:
# - $hg - the hg program being used (e.g. /usr/bin/hg)
# - $cmd - the name of the hg command being completed
# - $cmd_index - the index of $cmd in $COMP_WORDS
# - $cur - the current argument being completed
# - $prev - the argument before $cur
# - $global_args - "|"-separated list of global options that accept
#                  an argument (e.g. '--cwd|-R|--repository')
# - $canonical - 1 if we canonicalized $cmd before calling the function
#                0 otherwise
#

shopt -s extglob

_hg_cmd()
{
    HGPLAIN=1 "$hg" "$@" 2>/dev/null
}

_hg_commands()
{
    local commands
    commands="$(HGPLAINEXCEPT=alias _hg_cmd debugcomplete "$cur")" || commands=""
    COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$commands' -- "$cur"))
}

_hg_paths()
{
    local paths="$(_hg_cmd paths -q)"
    COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$paths' -- "$cur"))
}

_hg_repos()
{
    local i
    for i in $(compgen -d -- "$cur"); do
        test ! -d "$i"/.hg || COMPREPLY=(${COMPREPLY[@]:-} "$i")
    done
}

_hg_debugpathcomplete()
{
    local files="$(_hg_cmd debugpathcomplete $1 "$cur")"
    local IFS=$'\n'
    COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$files' -- "$cur"))
}

_hg_status()
{
    if [ -z "$HGCOMPLETE_NOSTATUS" ]; then
        local files="$(_hg_cmd status -n$1 "glob:$cur**")"
        local IFS=$'\n'
        COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$files' -- "$cur"))
    fi
}

_hg_branches()
{
    local branches="$(_hg_cmd branches -q)"
    local IFS=$'\n'
    COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$branches' -- "$cur"))
}

_hg_bookmarks()
{
    local bookmarks="$(_hg_cmd bookmarks -q)"
    local IFS=$'\n'
    COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$bookmarks' -- "$cur"))
}

_hg_labels()
{
    local labels="$(_hg_cmd debugnamecomplete "$cur")"
    local IFS=$'\n'
    COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$labels' -- "$cur"))
}

# this is "kind of" ugly...
_hg_count_non_option()
{
    local i count=0
    local filters="$1"

    for ((i=1; $i<=$COMP_CWORD; i++)); do
        if [[ "${COMP_WORDS[i]}" != -* ]]; then
            if [[ ${COMP_WORDS[i-1]} == @($filters|$global_args) ]]; then
                continue
            fi
            count=$(($count + 1))
        fi
    done

    echo $(($count - 1))
}

_hg_fix_wordlist()
{
    local LASTCHAR=' '
    if [ ${#COMPREPLY[@]} = 1 ]; then
        [ -d "$COMPREPLY" ] && LASTCHAR=/
        COMPREPLY=$(printf %q%s "$COMPREPLY" "$LASTCHAR")
    else
        for ((i=0; i < ${#COMPREPLY[@]}; i++)); do
            [ -d "${COMPREPLY[$i]}" ] && COMPREPLY[$i]=${COMPREPLY[$i]}/
        done
    fi
}

_hg()
{
    local cur prev cmd cmd_index opts i aliashg
    # global options that receive an argument
    local global_args='--cwd|-R|--repository'
    local hg="$1"
    local canonical=0

    aliashg=$(alias $hg 2>/dev/null)
    if [[ -n "$aliashg" ]]; then
      aliashg=${aliashg#"alias $hg='"}
      aliashg=${aliashg%"'"}
      hg=$aliashg
    fi

    COMPREPLY=()
    cur="$2"
    prev="$3"

    # searching for the command
    # (first non-option argument that doesn't follow a global option that
    #  receives an argument)
    for ((i=1; $i<=$COMP_CWORD; i++)); do
        if [[ ${COMP_WORDS[i]} != -* ]]; then
            if [[ ${COMP_WORDS[i-1]} != @($global_args) ]]; then
                cmd="${COMP_WORDS[i]}"
                cmd_index=$i
                break
            fi
        fi
    done

    if [[ "$cur" == -* ]]; then
        if [ "$(type -t "_hg_opt_$cmd")" = function ] && "_hg_opt_$cmd"; then
            _hg_fix_wordlist
            return
        fi

        opts=$(HGPLAINEXCEPT=alias _hg_cmd debugcomplete --options "$cmd")

        COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$opts' -- "$cur"))
        _hg_fix_wordlist
        return
    fi

    # global options
    case "$prev" in
        -R|--repository)
            _hg_paths
            _hg_repos
            _hg_fix_wordlist
            return
        ;;
        --cwd)
            # Stick with default bash completion
            _hg_fix_wordlist
            return
        ;;
    esac

    if [ -z "$cmd" ] || [ $COMP_CWORD -eq $i ]; then
        _hg_commands
        _hg_fix_wordlist
        return
    fi

    # try to generate completion candidates for whatever command the user typed
    local help
    if _hg_command_specific; then
        _hg_fix_wordlist
        return
    fi

    # canonicalize the command name and try again
    help=$(_hg_cmd help "$cmd")
    if [ $? -ne 0 ]; then
        # Probably either the command doesn't exist or it's ambiguous
        return
    fi
    cmd=${help#hg }
    cmd=${cmd%%[$' \n']*}
    canonical=1
    _hg_command_specific
    _hg_fix_wordlist
}

_hg_command_specific()
{
    if [ "$(type -t "_hg_cmd_$cmd")" = function ]; then
        "_hg_cmd_$cmd"
        return 0
    fi

    if [ "$cmd" != status ]; then
        case "$prev" in
            -r|--rev)
                if [[ $canonical = 1 || status != "$cmd"* ]]; then
                    _hg_labels
                    return 0
                fi
                return 1
            ;;
            -B|--bookmark)
                if [[ $canonical = 1 || status != "$cmd"* ]]; then
                    _hg_bookmarks
                    return 0
                fi
                return 1
            ;;
            -b|--branch)
                if [[ $canonical = 1 || status != "$cmd"* ]]; then
                    _hg_branches
                    return 0
                fi
                return 1
            ;;
        esac
    fi

    local aliascmd=$(_hg_cmd showconfig alias.$cmd | awk '{print $1}')
    [ -n "$aliascmd" ] && cmd=$aliascmd

    case "$cmd" in
        help)
            _hg_commands
        ;;
        export)
            if _hg_ext_mq_patchlist qapplied && [ "${COMPREPLY[*]}" ]; then
                return 0
            fi
            _hg_labels
        ;;
        manifest|update|up|checkout|co)
            _hg_labels
        ;;
        pull|push|outgoing|incoming)
            _hg_paths
            _hg_repos
        ;;
        paths)
            _hg_paths
        ;;
        add)
            _hg_status "u"
        ;;
        merge)
            _hg_labels
        ;;
        commit|ci|record|amend)
            _hg_status "mar"
        ;;
        remove|rm)
            _hg_debugpathcomplete -n
        ;;
        forget)
            _hg_debugpathcomplete -fa
        ;;
        diff)
            _hg_status "mar"
        ;;
        revert)
            _hg_status "mard"
        ;;
        clone)
            local count=$(_hg_count_non_option)
            if [ $count = 1 ]; then
                _hg_paths
            fi
            _hg_repos
        ;;
        debugindex|debugindexdot)
            COMPREPLY=(${COMPREPLY[@]:-} $(compgen -f -X "!*.i" -- "$cur"))
        ;;
        debugdata)
            COMPREPLY=(${COMPREPLY[@]:-} $(compgen -f -X "!*.d" -- "$cur"))
        ;;
        *)
            return 1
        ;;
    esac

    return 0
}

complete -o bashdefault -o default -o nospace -F _hg hg \
    || complete -o default -o nospace -F _hg hg


# Completion for commands provided by extensions

# bookmarks
_hg_cmd_bookmarks()
{
    _hg_bookmarks
    return
}

# mq
_hg_ext_mq_patchlist()
{
    local patches
    patches=$(_hg_cmd $1)
    if [ $? -eq 0 ] && [ "$patches" ]; then
        COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$patches' -- "$cur"))
        return 0
    fi
    return 1
}

_hg_ext_mq_queues()
{
    local root=$(_hg_cmd root)
    local n
    for n in $(cd "$root"/.hg && compgen -d -- "$cur"); do
        # I think we're usually not interested in the regular "patches" queue
        # so just filter it.
        if [ "$n" != patches ] && [ -e "$root/.hg/$n/series" ]; then
            COMPREPLY=(${COMPREPLY[@]:-} "$n")
        fi
    done
}

_hg_cmd_qpop()
{
    if [[ "$prev" = @(-n|--name) ]]; then
        _hg_ext_mq_queues
        return
    fi
    _hg_ext_mq_patchlist qapplied
}

_hg_cmd_qpush()
{
    if [[ "$prev" = @(-n|--name) ]]; then
        _hg_ext_mq_queues
        return
    fi
    _hg_ext_mq_patchlist qunapplied
}

_hg_cmd_qgoto()
{
    if [[ "$prev" = @(-n|--name) ]]; then
        _hg_ext_mq_queues
        return
    fi
    _hg_ext_mq_patchlist qseries
}

_hg_cmd_qdelete()
{
    local qcmd=qunapplied
    if [[ "$prev" = @(-r|--rev) ]]; then
        qcmd=qapplied
    fi
    _hg_ext_mq_patchlist $qcmd
}

_hg_cmd_qfinish()
{
    if [[ "$prev" = @(-a|--applied) ]]; then
        return
    fi
    _hg_ext_mq_patchlist qapplied
}

_hg_cmd_qsave()
{
    if [[ "$prev" = @(-n|--name) ]]; then
        _hg_ext_mq_queues
        return
    fi
}

_hg_cmd_rebase() {
   if [[ "$prev" = @(-s|--source|-d|--dest|-b|--base|-r|--rev) ]]; then
       _hg_labels
       return
   fi
}

_hg_cmd_strip()
{
    if [[ "$prev" = @(-B|--bookmark) ]]; then
        _hg_bookmarks
        return
    fi
    _hg_labels
}

_hg_cmd_qcommit()
{
    local root=$(_hg_cmd root)
    # this is run in a sub-shell, so we can't use _hg_status
    local files=$(cd "$root/.hg/patches" && _hg_cmd status -nmar)
    COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$files' -- "$cur"))
}

_hg_cmd_qfold()
{
    _hg_ext_mq_patchlist qunapplied
}

_hg_cmd_qrename()
{
    _hg_ext_mq_patchlist qseries
}

_hg_cmd_qheader()
{
    _hg_ext_mq_patchlist qseries
}

_hg_cmd_qclone()
{
    local count=$(_hg_count_non_option)
    if [ $count = 1 ]; then
        _hg_paths
    fi
    _hg_repos
}

_hg_ext_mq_guards()
{
    _hg_cmd qselect --series | sed -e 's/^.//'
}

_hg_cmd_qselect()
{
    local guards=$(_hg_ext_mq_guards)
    COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$guards' -- "$cur"))
}

_hg_cmd_qguard()
{
    local prefix=''

    if [[ "$cur" == +* ]]; then
        prefix=+
    elif [[ "$cur" == -* ]]; then
        prefix=-
    fi
    local ncur=${cur#[-+]}

    if ! [ "$prefix" ]; then
        _hg_ext_mq_patchlist qseries
        return
    fi

    local guards=$(_hg_ext_mq_guards)
    COMPREPLY=(${COMPREPLY[@]:-} $(compgen -P $prefix -W '$guards' -- "$ncur"))
}

_hg_opt_qguard()
{
    local i
    for ((i=cmd_index+1; i<=COMP_CWORD; i++)); do
        if [[ ${COMP_WORDS[i]} != -* ]]; then
            if [[ ${COMP_WORDS[i-1]} != @($global_args) ]]; then
                _hg_cmd_qguard
                return 0
            fi
        elif [ "${COMP_WORDS[i]}" = -- ]; then
            _hg_cmd_qguard
            return 0
        fi
    done
    return 1
}

_hg_cmd_qqueue()
{
    local q
    local queues
    local opts="--list --create --rename --delete --purge"

    queues=$( _hg_cmd qqueue --quiet )

    COMPREPLY=( $( compgen -W "${opts} ${queues}" "${cur}" ) )
}


# hbisect
_hg_cmd_bisect()
{
    local i subcmd

    # find the sub-command
    for ((i=cmd_index+1; i<=COMP_CWORD; i++)); do
        if [[ ${COMP_WORDS[i]} != -* ]]; then
            if [[ ${COMP_WORDS[i-1]} != @($global_args) ]]; then
                subcmd="${COMP_WORDS[i]}"
                break
            fi
        fi
    done

    if [ -z "$subcmd" ] || [ $COMP_CWORD -eq $i ] || [ "$subcmd" = help ]; then
        COMPREPLY=(${COMPREPLY[@]:-}
                   $(compgen -W 'bad good help init next reset' -- "$cur"))
        return
    fi

    case "$subcmd" in
        good|bad)
            _hg_labels
            ;;
    esac

    return
}


# patchbomb
_hg_cmd_email()
{
    case "$prev" in
        -c|--cc|-t|--to|-f|--from|--bcc)
            # we need an e-mail address. let the user provide a function
            # to get them
            if [ "$(type -t _hg_emails)" = function ]; then
                local arg=to
                if [[ "$prev" == @(-f|--from) ]]; then
                    arg=from
                fi
                local addresses=$(_hg_emails $arg)
                COMPREPLY=(${COMPREPLY[@]:-}
                           $(compgen -W '$addresses' -- "$cur"))
            fi
            return
            ;;
        -m|--mbox)
            # fallback to standard filename completion
            return
            ;;
        -s|--subject)
            # free form string
            return
            ;;
    esac

    _hg_labels
    return
}


# gpg
_hg_cmd_sign()
{
    _hg_labels
}


# transplant
_hg_cmd_transplant()
{
    case "$prev" in
        -s|--source)
            _hg_paths
            _hg_repos
            return
            ;;
        --filter)
            # standard filename completion
            return
            ;;
    esac

    # all other transplant options values and command parameters are revisions
    _hg_labels
    return
}

# shelve
_hg_shelves()
{
    local shelves="$(_hg_cmd shelve -ql)"
    local IFS=$'\n'
    COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$shelves' -- "$cur"))
}

_hg_cmd_shelve()
{
    if [[ "$prev" = @(-d|--delete|-l|--list|-p|--patch|--stat) ]]; then
        _hg_shelves
    else
        _hg_status "mard"
    fi
}

_hg_cmd_unshelve()
{
    _hg_shelves
}