exec: remove useless initialisation

[jimtcl.git] / tclcompat.tcl

# Loads some Tcl-compatible features.
# I/O commands, parray, open |..., errorInfo, ::env
# try, throw, file copy, file delete -force
#
# (c) 2008 Steve Bennett <steveb@workware.net.au>


# Set up the ::env array
set env [env]

# Provide Tcl-compatible I/O commands
if {[info commands stdout] ne ""} {
        # Tcl-compatible I/O commands
        foreach p {gets flush close eof seek tell} {
                proc $p {chan args} {p} {
                        tailcall $chan $p {*}$args
                }
        }
        unset p

        # puts is complicated by -nonewline
        #
        proc puts {{-nonewline {}} {chan stdout} msg} {
                if {${-nonewline} ni {-nonewline {}}} {
                        tailcall ${-nonewline} puts $msg
                }
                tailcall $chan puts {*}${-nonewline} $msg
        }

        # read is complicated by -nonewline
        #
        # read chan ?maxchars?
        # read -nonewline chan
        proc read {{-nonewline {}} chan} {
                if {${-nonewline} ni {-nonewline {}}} {
                        tailcall ${-nonewline} read {*}${chan}
                }
                tailcall $chan read {*}${-nonewline}
        }

        proc fconfigure {f args} {
                foreach {n v} $args {
                        switch -glob -- $n {
                                -bl* {
                                        $f ndelay $(!$v)
                                }
                                -bu* {
                                        $f buffering $v
                                }
                                -tr* {
                                        # Just ignore -translation
                                }
                                default {
                                        return -code error "fconfigure: unknown option $n"
                                }
                        }
                }
        }
}

# fileevent isn't needed in Jim, but provide it for compatibility
proc fileevent {args} {
        tailcall {*}$args
}

# Second, optional argument is a glob pattern
# Third, optional argument is a "putter" function
proc parray {arrayname {pattern *} {puts puts}} {
        upvar $arrayname a

        set max 0
        foreach name [array names a $pattern]] {
                if {[string length $name] > $max} {
                        set max [string length $name]
                }
        }
        incr max [string length $arrayname]
        incr max 2
        foreach name [lsort [array names a $pattern]] {
                $puts [format "%-${max}s = %s" $arrayname\($name\) $a($name)]
        }
}

# Implements 'file copy' - single file mode only
proc {file copy} {{force {}} source target} {
        try {
                if {$force ni {{} -force}} {
                        error "bad option \"$force\": should be -force"
                }

                set in [open $source rb]

                if {[file exists $target]} {
                        if {$force eq ""} {
                                error "error copying \"$source\" to \"$target\": file already exists"
                        }
                        # If source and target are the same, nothing to do
                        if {$source eq $target} {
                                return
                        }
                        # Hard linked, or case-insensitive filesystem
                        # Note: mingw returns ino=0 for every file :-(
                        file stat $source ss
                        file stat $target ts
                        if {$ss(dev) == $ts(dev) && $ss(ino) == $ts(ino) && $ss(ino)} {
                                return
                        }
                }
                set out [open $target wb]
                $in copyto $out
                $out close
        } on error {msg opts} {
                incr opts(-level)
                return {*}$opts $msg
        } finally {
                catch {$in close}
        }
}

# 'open "|..." ?mode?" will invoke this wrapper around exec/pipe
# Note that we return a lambda that also provides the 'pid' command
proc popen {cmd {mode r}} {
        lassign [pipe] r w
        try {
                if {[string match "w*" $mode]} {
                        lappend cmd <@$r &
                        set pids [exec {*}$cmd]
                        $r close
                        set f $w
                } else {
                        lappend cmd >@$w &
                        set pids [exec {*}$cmd]
                        $w close
                        set f $r
                }
                lambda {cmd args} {f pids} {
                        if {$cmd eq "pid"} {
                                return $pids
                        }
                        if {$cmd eq "getfd"} {
                                $f getfd
                        }
                        if {$cmd eq "close"} {
                                $f close
                                # And wait for the child processes to complete
                                set retopts {}
                                foreach p $pids {
                                        lassign [wait $p] status - rc
                                        if {$status eq "CHILDSTATUS"} {
                                                if {$rc == 0} {
                                                        continue
                                                }
                                                set msg "child process exited abnormally"
                                        } else {
                                                set msg "child killed: received signal"
                                        }
                                        set retopts [list -code error -errorcode [list $status $p $rc] $msg]
                                }
                                return {*}$retopts
                        }
                        tailcall $f $cmd {*}$args
                }
        } on error {error opts} {
                $r close
                $w close
                error $error
        }
}

# A wrapper around 'pid' that can return the pids for 'popen'
local proc pid {{channelId {}}} {
        if {$channelId eq ""} {
                tailcall upcall pid
        }
        if {[catch {$channelId tell}]} {
                return -code error "can not find channel named \"$channelId\""
        }
        if {[catch {$channelId pid} pids]} {
                return ""
        }
        return $pids
}

# try/on/finally conceptually similar to Tcl 8.6
#
# Usage: try ?catchopts? script ?onclause ...? ?finallyclause?
#
# Where:
#       catchopts is: options for catch such as -nobreak, -signal
#        onclause is: on codes {?resultvar? ?optsvar?} script
#           codes is: a list of return codes (ok, error, etc. or integers), or * for any
#   finallyclause is: finally script
proc try {args} {
        set catchopts {}
        while {[string match -* [lindex $args 0]]} {
                set args [lassign $args opt]
                if {$opt eq "--"} {
                        break
                }
                lappend catchopts $opt
        }
        if {[llength $args] == 0} {
                return -code error {wrong # args: should be "try ?options? script ?argument ...?"}
        }
        set args [lassign $args script]
        set code [catch -eval {*}$catchopts {uplevel 1 $script} msg opts]

        set handled 0

        foreach {on codes vars script} $args {
                switch -- $on \
                        on {
                                if {!$handled && ($codes eq "*" || [info returncode $code] in $codes)} {
                                        lassign $vars msgvar optsvar
                                        if {$msgvar ne ""} {
                                                upvar $msgvar hmsg
                                                set hmsg $msg
                                        }
                                        if {$optsvar ne ""} {
                                                upvar $optsvar hopts
                                                set hopts $opts
                                        }
                                        # Override any body result
                                        set code [catch {uplevel 1 $script} msg opts]
                                        incr handled
                                }
                        } \
                        finally {
                                set finalcode [catch {uplevel 1 $codes} finalmsg finalopts]
                                if {$finalcode} {
                                        # Override any body or handler result
                                        set code $finalcode
                                        set msg $finalmsg
                                        set opts $finalopts
                                }
                                break
                        } \
                        default {
                                return -code error "try: expected 'on' or 'finally', got '$on'"
                        }
        }

        if {$code} {
                incr opts(-level)
                return {*}$opts $msg
        }
        return $msg
}

# Generates an exception with the given code (ok, error, etc. or an integer)
# and the given message
proc throw {code {msg ""}} {
        return -code $code $msg
}

# Helper for "file delete -force"
proc {file delete force} {path} {
        foreach e [readdir $path] {
                file delete -force $path/$e
        }
        file delete $path
}