#!/bin/sh
# Tcl ignores the next line -*- tcl -*- \
exec wish "$0" -- "${1+$@}"

# Copyright (C) 2005 Paul Mackerras.  All rights reserved.
# This program is free software; it may be used, copied, modified
# and distributed under the terms of the GNU General Public Licence,
# either version 2, or (at your option) any later version.

proc getcommits {rargs} {
    global commits commfd phase canv mainfont env
    global startmsecs nextupdate
    global ctext maincursor textcursor leftover

    # check that we can find a .git directory somewhere...
    if {[info exists env(GIT_DIR)]} {
	set gitdir $env(GIT_DIR)
    } else {
	set gitdir ".git"
    }
    if {![file isdirectory $gitdir]} {
	error_popup "Cannot find the git directory \"$gitdir\"."
	exit 1
    }
    set commits {}
    set phase getcommits
    set startmsecs [clock clicks -milliseconds]
    set nextupdate [expr $startmsecs + 100]
    if [catch {
	set parse_args [concat --default HEAD $rargs]
	set parsed_args [split [eval exec git-rev-parse $parse_args] "\n"]
    }] {
	# if git-rev-parse failed for some reason...
	if {$rargs == {}} {
	    set rargs HEAD
	}
	set parsed_args $rargs
    }
    if [catch {
	set commfd [open "|git-rev-list --header --merge-order $parsed_args" r]
    } err] {
	puts stderr "Error executing git-rev-list: $err"
	exit 1
    }
    set leftover {}
    fconfigure $commfd -blocking 0 -translation binary
    fileevent $commfd readable "getcommitlines $commfd"
    $canv delete all
    $canv create text 3 3 -anchor nw -text "Reading commits..." \
	-font $mainfont -tags textitems
    . config -cursor watch
    $ctext config -cursor watch
}

proc getcommitlines {commfd}  {
    global commits parents cdate children nchildren
    global commitlisted phase commitinfo nextupdate
    global stopped redisplaying leftover

    set stuff [read $commfd]
    if {$stuff == {}} {
	if {![eof $commfd]} return
	# this works around what is apparently a bug in Tcl...
	fconfigure $commfd -blocking 1
	if {![catch {close $commfd} err]} {
	    after idle finishcommits
	    return
	}
	if {[string range $err 0 4] == "usage"} {
	    set err \
{Gitk: error reading commits: bad arguments to git-rev-list.
(Note: arguments to gitk are passed to git-rev-list
to allow selection of commits to be displayed.)}
	} else {
	    set err "Error reading commits: $err"
	}
	error_popup $err
	exit 1
    }
    set start 0
    while 1 {
	set i [string first "\0" $stuff $start]
	if {$i < 0} {
	    set leftover [string range $stuff $start end]
	    return
	}
	set cmit [string range $stuff $start [expr {$i - 1}]]
	if {$start == 0} {
	    set cmit "$leftover$cmit"
	}
	set start [expr {$i + 1}]
	if {![regexp {^([0-9a-f]{40})\n} $cmit match id]} {
	    error_popup "Can't parse git-rev-list output: {$cmit}"
	    exit 1
	}
	set cmit [string range $cmit 41 end]
	lappend commits $id
	set commitlisted($id) 1
	parsecommit $id $cmit 1
	drawcommit $id
	if {[clock clicks -milliseconds] >= $nextupdate} {
	    doupdate
	}
	while {$redisplaying} {
	    set redisplaying 0
	    if {$stopped == 1} {
		set stopped 0
		set phase "getcommits"
		foreach id $commits {
		    drawcommit $id
		    if {$stopped} break
		    if {[clock clicks -milliseconds] >= $nextupdate} {
			doupdate
		    }
		}
	    }
	}
    }
}

proc doupdate {} {
    global commfd nextupdate

    incr nextupdate 100
    fileevent $commfd readable {}
    update
    fileevent $commfd readable "getcommitlines $commfd"
}

proc readcommit {id} {
    if [catch {set contents [exec git-cat-file commit $id]}] return
    parsecommit $id $contents 0
}

proc parsecommit {id contents listed} {
    global commitinfo children nchildren parents nparents cdate ncleft

    set inhdr 1
    set comment {}
    set headline {}
    set auname {}
    set audate {}
    set comname {}
    set comdate {}
    if {![info exists nchildren($id)]} {
	set children($id) {}
	set nchildren($id) 0
	set ncleft($id) 0
    }
    set parents($id) {}
    set nparents($id) 0
    foreach line [split $contents "\n"] {
	if {$inhdr} {
	    if {$line == {}} {
		set inhdr 0
	    } else {
		set tag [lindex $line 0]
		if {$tag == "parent"} {
		    set p [lindex $line 1]
		    if {![info exists nchildren($p)]} {
			set children($p) {}
			set nchildren($p) 0
			set ncleft($p) 0
		    }
		    lappend parents($id) $p
		    incr nparents($id)
		    # sometimes we get a commit that lists a parent twice...
		    if {$listed && [lsearch -exact $children($p) $id] < 0} {
			lappend children($p) $id
			incr nchildren($p)
			incr ncleft($p)
		    }
		} elseif {$tag == "author"} {
		    set x [expr {[llength $line] - 2}]
		    set audate [lindex $line $x]
		    set auname [lrange $line 1 [expr {$x - 1}]]
		} elseif {$tag == "committer"} {
		    set x [expr {[llength $line] - 2}]
		    set comdate [lindex $line $x]
		    set comname [lrange $line 1 [expr {$x - 1}]]
		}
	    }
	} else {
	    if {$comment == {}} {
		set headline [string trim $line]
	    } else {
		append comment "\n"
	    }
	    if {!$listed} {
		# git-rev-list indents the comment by 4 spaces;
		# if we got this via git-cat-file, add the indentation
		append comment "    "
	    }
	    append comment $line
	}
    }
    if {$audate != {}} {
	set audate [clock format $audate -format "%Y-%m-%d %H:%M:%S"]
    }
    if {$comdate != {}} {
	set cdate($id) $comdate
	set comdate [clock format $comdate -format "%Y-%m-%d %H:%M:%S"]
    }
    set commitinfo($id) [list $headline $auname $audate \
			     $comname $comdate $comment]
}

proc readrefs {} {
    global tagids idtags headids idheads
    set tags [glob -nocomplain -types f .git/refs/tags/*]
    foreach f $tags {
	catch {
	    set fd [open $f r]
	    set line [read $fd]
	    if {[regexp {^[0-9a-f]{40}} $line id]} {
		set direct [file tail $f]
		set tagids($direct) $id
		lappend idtags($id) $direct
		set contents [split [exec git-cat-file tag $id] "\n"]
		set obj {}
		set type {}
		set tag {}
		foreach l $contents {
		    if {$l == {}} break
		    switch -- [lindex $l 0] {
			"object" {set obj [lindex $l 1]}
			"type" {set type [lindex $l 1]}
			"tag" {set tag [string range $l 4 end]}
		    }
		}
		if {$obj != {} && $type == "commit" && $tag != {}} {
		    set tagids($tag) $obj
		    lappend idtags($obj) $tag
		}
	    }
	    close $fd
	}
    }
    set heads [glob -nocomplain -types f .git/refs/heads/*]
    foreach f $heads {
	catch {
	    set fd [open $f r]
	    set line [read $fd 40]
	    if {[regexp {^[0-9a-f]{40}} $line id]} {
		set head [file tail $f]
		set headids($head) $line
		lappend idheads($line) $head
	    }
	    close $fd
	}
    }
}

proc error_popup msg {
    set w .error
    toplevel $w
    wm transient $w .
    message $w.m -text $msg -justify center -aspect 400
    pack $w.m -side top -fill x -padx 20 -pady 20
    button $w.ok -text OK -command "destroy $w"
    pack $w.ok -side bottom -fill x
    bind $w <Visibility> "grab $w; focus $w"
    tkwait window $w
}

proc makewindow {} {
    global canv canv2 canv3 linespc charspc ctext cflist textfont
    global findtype findloc findstring fstring geometry
    global entries sha1entry sha1string sha1but
    global maincursor textcursor
    global rowctxmenu

    menu .bar
    .bar add cascade -label "File" -menu .bar.file
    menu .bar.file
    .bar.file add command -label "Quit" -command doquit
    menu .bar.help
    .bar add cascade -label "Help" -menu .bar.help
    .bar.help add command -label "About gitk" -command about
    . configure -menu .bar

    if {![info exists geometry(canv1)]} {
	set geometry(canv1) [expr 45 * $charspc]
	set geometry(canv2) [expr 30 * $charspc]
	set geometry(canv3) [expr 15 * $charspc]
	set geometry(canvh) [expr 25 * $linespc + 4]
	set geometry(ctextw) 80
	set geometry(ctexth) 30
	set geometry(cflistw) 30
    }
    panedwindow .ctop -orient vertical
    if {[info exists geometry(width)]} {
	.ctop conf -width $geometry(width) -height $geometry(height)
	set texth [expr {$geometry(height) - $geometry(canvh) - 56}]
	set geometry(ctexth) [expr {($texth - 8) /
				    [font metrics $textfont -linespace]}]
    }
    frame .ctop.top
    frame .ctop.top.bar
    pack .ctop.top.bar -side bottom -fill x
    set cscroll .ctop.top.csb
    scrollbar $cscroll -command {allcanvs yview} -highlightthickness 0
    pack $cscroll -side right -fill y
    panedwindow .ctop.top.clist -orient horizontal -sashpad 0 -handlesize 4
    pack .ctop.top.clist -side top -fill both -expand 1
    .ctop add .ctop.top
    set canv .ctop.top.clist.canv
    canvas $canv -height $geometry(canvh) -width $geometry(canv1) \
	-bg white -bd 0 \
	-yscrollincr $linespc -yscrollcommand "$cscroll set"
    .ctop.top.clist add $canv
    set canv2 .ctop.top.clist.canv2
    canvas $canv2 -height $geometry(canvh) -width $geometry(canv2) \
	-bg white -bd 0 -yscrollincr $linespc
    .ctop.top.clist add $canv2
    set canv3 .ctop.top.clist.canv3
    canvas $canv3 -height $geometry(canvh) -width $geometry(canv3) \
	-bg white -bd 0 -yscrollincr $linespc
    .ctop.top.clist add $canv3
    bind .ctop.top.clist <Configure> {resizeclistpanes %W %w}

    set sha1entry .ctop.top.bar.sha1
    set entries $sha1entry
    set sha1but .ctop.top.bar.sha1label
    button $sha1but -text "SHA1 ID: " -state disabled -relief flat \
	-command gotocommit -width 8
    $sha1but conf -disabledforeground [$sha1but cget -foreground]
    pack .ctop.top.bar.sha1label -side left
    entry $sha1entry -width 40 -font $textfont -textvariable sha1string
    trace add variable sha1string write sha1change
    pack $sha1entry -side left -pady 2
    button .ctop.top.bar.findbut -text "Find" -command dofind
    pack .ctop.top.bar.findbut -side left
    set findstring {}
    set fstring .ctop.top.bar.findstring
    lappend entries $fstring
    entry $fstring -width 30 -font $textfont -textvariable findstring
    pack $fstring -side left -expand 1 -fill x
    set findtype Exact
    tk_optionMenu .ctop.top.bar.findtype findtype Exact IgnCase Regexp
    set findloc "All fields"
    tk_optionMenu .ctop.top.bar.findloc findloc "All fields" Headline \
	Comments Author Committer
    pack .ctop.top.bar.findloc -side right
    pack .ctop.top.bar.findtype -side right

    panedwindow .ctop.cdet -orient horizontal
    .ctop add .ctop.cdet
    frame .ctop.cdet.left
    set ctext .ctop.cdet.left.ctext
    text $ctext -bg white -state disabled -font $textfont \
	-width $geometry(ctextw) -height $geometry(ctexth) \
	-yscrollcommand ".ctop.cdet.left.sb set"
    scrollbar .ctop.cdet.left.sb -command "$ctext yview"
    pack .ctop.cdet.left.sb -side right -fill y
    pack $ctext -side left -fill both -expand 1
    .ctop.cdet add .ctop.cdet.left

    $ctext tag conf filesep -font [concat $textfont bold]
    $ctext tag conf hunksep -back blue -fore white
    $ctext tag conf d0 -back "#ff8080"
    $ctext tag conf d1 -back green
    $ctext tag conf found -back yellow

    frame .ctop.cdet.right
    set cflist .ctop.cdet.right.cfiles
    listbox $cflist -bg white -selectmode extended -width $geometry(cflistw) \
	-yscrollcommand ".ctop.cdet.right.sb set"
    scrollbar .ctop.cdet.right.sb -command "$cflist yview"
    pack .ctop.cdet.right.sb -side right -fill y
    pack $cflist -side left -fill both -expand 1
    .ctop.cdet add .ctop.cdet.right
    bind .ctop.cdet <Configure> {resizecdetpanes %W %w}

    pack .ctop -side top -fill both -expand 1

    bindall <1> {selcanvline %W %x %y}
    #bindall <B1-Motion> {selcanvline %W %x %y}
    bindall <ButtonRelease-4> "allcanvs yview scroll -5 units"
    bindall <ButtonRelease-5> "allcanvs yview scroll 5 units"
    bindall <2> "allcanvs scan mark 0 %y"
    bindall <B2-Motion> "allcanvs scan dragto 0 %y"
    bind . <Key-Up> "selnextline -1"
    bind . <Key-Down> "selnextline 1"
    bind . <Key-Prior> "allcanvs yview scroll -1 pages"
    bind . <Key-Next> "allcanvs yview scroll 1 pages"
    bindkey <Key-Delete> "$ctext yview scroll -1 pages"
    bindkey <Key-BackSpace> "$ctext yview scroll -1 pages"
    bindkey <Key-space> "$ctext yview scroll 1 pages"
    bindkey p "selnextline -1"
    bindkey n "selnextline 1"
    bindkey b "$ctext yview scroll -1 pages"
    bindkey d "$ctext yview scroll 18 units"
    bindkey u "$ctext yview scroll -18 units"
    bindkey / findnext
    bindkey ? findprev
    bindkey f nextfile
    bind . <Control-q> doquit
    bind . <Control-f> dofind
    bind . <Control-g> findnext
    bind . <Control-r> findprev
    bind . <Control-equal> {incrfont 1}
    bind . <Control-KP_Add> {incrfont 1}
    bind . <Control-minus> {incrfont -1}
    bind . <Control-KP_Subtract> {incrfont -1}
    bind $cflist <<ListboxSelect>> listboxsel
    bind . <Destroy> {savestuff %W}
    bind . <Button-1> "click %W"
    bind $fstring <Key-Return> dofind
    bind $sha1entry <Key-Return> gotocommit
    bind $sha1entry <<PasteSelection>> clearsha1

    set maincursor [. cget -cursor]
    set textcursor [$ctext cget -cursor]

    set rowctxmenu .rowctxmenu
    menu $rowctxmenu -tearoff 0
    $rowctxmenu add command -label "Diff this -> selected" \
	-command {diffvssel 0}
    $rowctxmenu add command -label "Diff selected -> this" \
	-command {diffvssel 1}
}

# when we make a key binding for the toplevel, make sure
# it doesn't get triggered when that key is pressed in the
# find string entry widget.
proc bindkey {ev script} {
    global entries
    bind . $ev $script
    set escript [bind Entry $ev]
    if {$escript == {}} {
	set escript [bind Entry <Key>]
    }
    foreach e $entries {
	bind $e $ev "$escript; break"
    }
}

# set the focus back to the toplevel for any click outside
# the entry widgets
proc click {w} {
    global entries
    foreach e $entries {
	if {$w == $e} return
    }
    focus .
}

proc savestuff {w} {
    global canv canv2 canv3 ctext cflist mainfont textfont
    global stuffsaved
    if {$stuffsaved} return
    if {![winfo viewable .]} return
    catch {
	set f [open "~/.gitk-new" w]
	puts $f "set mainfont {$mainfont}"
	puts $f "set textfont {$textfont}"
	puts $f "set geometry(width) [winfo width .ctop]"
	puts $f "set geometry(height) [winfo height .ctop]"
	puts $f "set geometry(canv1) [expr [winfo width $canv]-2]"
	puts $f "set geometry(canv2) [expr [winfo width $canv2]-2]"
	puts $f "set geometry(canv3) [expr [winfo width $canv3]-2]"
	puts $f "set geometry(canvh) [expr [winfo height $canv]-2]"
	set wid [expr {([winfo width $ctext] - 8) \
			   / [font measure $textfont "0"]}]
	puts $f "set geometry(ctextw) $wid"
	set wid [expr {([winfo width $cflist] - 11) \
			   / [font measure [$cflist cget -font] "0"]}]
	puts $f "set geometry(cflistw) $wid"
	close $f
	file rename -force "~/.gitk-new" "~/.gitk"
    }
    set stuffsaved 1
}

proc resizeclistpanes {win w} {
    global oldwidth
    if [info exists oldwidth($win)] {
	set s0 [$win sash coord 0]
	set s1 [$win sash coord 1]
	if {$w < 60} {
	    set sash0 [expr {int($w/2 - 2)}]
	    set sash1 [expr {int($w*5/6 - 2)}]
	} else {
	    set factor [expr {1.0 * $w / $oldwidth($win)}]
	    set sash0 [expr {int($factor * [lindex $s0 0])}]
	    set sash1 [expr {int($factor * [lindex $s1 0])}]
	    if {$sash0 < 30} {
		set sash0 30
	    }
	    if {$sash1 < $sash0 + 20} {
		set sash1 [expr $sash0 + 20]
	    }
	    if {$sash1 > $w - 10} {
		set sash1 [expr $w - 10]
		if {$sash0 > $sash1 - 20} {
		    set sash0 [expr $sash1 - 20]
		}
	    }
	}
	$win sash place 0 $sash0 [lindex $s0 1]
	$win sash place 1 $sash1 [lindex $s1 1]
    }
    set oldwidth($win) $w
}

proc resizecdetpanes {win w} {
    global oldwidth
    if [info exists oldwidth($win)] {
	set s0 [$win sash coord 0]
	if {$w < 60} {
	    set sash0 [expr {int($w*3/4 - 2)}]
	} else {
	    set factor [expr {1.0 * $w / $oldwidth($win)}]
	    set sash0 [expr {int($factor * [lindex $s0 0])}]
	    if {$sash0 < 45} {
		set sash0 45
	    }
	    if {$sash0 > $w - 15} {
		set sash0 [expr $w - 15]
	    }
	}
	$win sash place 0 $sash0 [lindex $s0 1]
    }
    set oldwidth($win) $w
}

proc allcanvs args {
    global canv canv2 canv3
    eval $canv $args
    eval $canv2 $args
    eval $canv3 $args
}

proc bindall {event action} {
    global canv canv2 canv3
    bind $canv $event $action
    bind $canv2 $event $action
    bind $canv3 $event $action
}

proc about {} {
    set w .about
    if {[winfo exists $w]} {
	raise $w
	return
    }
    toplevel $w
    wm title $w "About gitk"
    message $w.m -text {
Gitk version 1.2

Copyright © 2005 Paul Mackerras

Use and redistribute under the terms of the GNU General Public License} \
	    -justify center -aspect 400
    pack $w.m -side top -fill x -padx 20 -pady 20
    button $w.ok -text Close -command "destroy $w"
    pack $w.ok -side bottom
}

proc assigncolor {id} {
    global commitinfo colormap commcolors colors nextcolor
    global parents nparents children nchildren
    global cornercrossings crossings

    if [info exists colormap($id)] return
    set ncolors [llength $colors]
    if {$nparents($id) <= 1 && $nchildren($id) == 1} {
	set child [lindex $children($id) 0]
	if {[info exists colormap($child)]
	    && $nparents($child) == 1} {
	    set colormap($id) $colormap($child)
	    return
	}
    }
    set badcolors {}
    if {[info exists cornercrossings($id)]} {
	foreach x $cornercrossings($id) {
	    if {[info exists colormap($x)]
		&& [lsearch -exact $badcolors $colormap($x)] < 0} {
		lappend badcolors $colormap($x)
	    }
	}
	if {[llength $badcolors] >= $ncolors} {
	    set badcolors {}
	}
    }
    set origbad $badcolors
    if {[llength $badcolors] < $ncolors - 1} {
	if {[info exists crossings($id)]} {
	    foreach x $crossings($id) {
		if {[info exists colormap($x)]
		    && [lsearch -exact $badcolors $colormap($x)] < 0} {
		    lappend badcolors $colormap($x)
		}
	    }
	    if {[llength $badcolors] >= $ncolors} {
		set badcolors $origbad
	    }
	}
	set origbad $badcolors
    }
    if {[llength $badcolors] < $ncolors - 1} {
	foreach child $children($id) {
	    if {[info exists colormap($child)]
		&& [lsearch -exact $badcolors $colormap($child)] < 0} {
		lappend badcolors $colormap($child)
	    }
	    if {[info exists parents($child)]} {
		foreach p $parents($child) {
		    if {[info exists colormap($p)]
			&& [lsearch -exact $badcolors $colormap($p)] < 0} {
			lappend badcolors $colormap($p)
		    }
		}
	    }
	}
	if {[llength $badcolors] >= $ncolors} {
	    set badcolors $origbad
	}
    }
    for {set i 0} {$i <= $ncolors} {incr i} {
	set c [lindex $colors $nextcolor]
	if {[incr nextcolor] >= $ncolors} {
	    set nextcolor 0
	}
	if {[lsearch -exact $badcolors $c]} break
    }
    set colormap($id) $c
}

proc initgraph {} {
    global canvy canvy0 lineno numcommits lthickness nextcolor linespc
    global mainline sidelines
    global nchildren ncleft

    allcanvs delete all
    set nextcolor 0
    set canvy $canvy0
    set lineno -1
    set numcommits 0
    set lthickness [expr {int($linespc / 9) + 1}]
    catch {unset mainline}
    catch {unset sidelines}
    foreach id [array names nchildren] {
	set ncleft($id) $nchildren($id)
    }
}

proc bindline {t id} {
    global canv

    $canv bind $t <Enter> "lineenter %x %y $id"
    $canv bind $t <Motion> "linemotion %x %y $id"
    $canv bind $t <Leave> "lineleave $id"
    $canv bind $t <Button-1> "lineclick %x %y $id"
}

proc drawcommitline {level} {
    global parents children nparents nchildren todo
    global canv canv2 canv3 mainfont namefont canvx0 canvy linespc
    global lineid linehtag linentag linedtag commitinfo
    global colormap numcommits currentparents dupparents
    global oldlevel oldnlines oldtodo
    global idtags idline idheads
    global lineno lthickness mainline sidelines
    global commitlisted rowtextx

    incr numcommits
    incr lineno
    set id [lindex $todo $level]
    set lineid($lineno) $id
    set idline($id) $lineno
    set ofill [expr {[info exists commitlisted($id)]? "blue": "white"}]
    if {![info exists commitinfo($id)]} {
	readcommit $id
	if {![info exists commitinfo($id)]} {
	    set commitinfo($id) {"No commit information available"}
	    set nparents($id) 0
	}
    }
    assigncolor $id
    set currentparents {}
    set dupparents {}
    if {[info exists commitlisted($id)] && [info exists parents($id)]} {
	foreach p $parents($id) {
	    if {[lsearch -exact $currentparents $p] < 0} {
		lappend currentparents $p
	    } else {
		# remember that this parent was listed twice
		lappend dupparents $p
	    }
	}
    }
    set x [expr $canvx0 + $level * $linespc]
    set y1 $canvy
    set canvy [expr $canvy + $linespc]
    allcanvs conf -scrollregion \
	[list 0 0 0 [expr $y1 + 0.5 * $linespc + 2]]
    if {[info exists mainline($id)]} {
	lappend mainline($id) $x $y1
	set t [$canv create line $mainline($id) \
		   -width $lthickness -fill $colormap($id)]
	$canv lower $t
	bindline $t $id
    }
    if {[info exists sidelines($id)]} {
	foreach ls $sidelines($id) {
	    set coords [lindex $ls 0]
	    set thick [lindex $ls 1]
	    set t [$canv create line $coords -fill $colormap($id) \
		       -width [expr {$thick * $lthickness}]]
	    $canv lower $t
	    bindline $t $id
	}
    }
    set orad [expr {$linespc / 3}]
    set t [$canv create oval [expr $x - $orad] [expr $y1 - $orad] \
	       [expr $x + $orad - 1] [expr $y1 + $orad - 1] \
	       -fill $ofill -outline black -width 1]
    $canv raise $t
    $canv bind $t <1> {selcanvline {} %x %y}
    set xt [expr $canvx0 + [llength $todo] * $linespc]
    if {[llength $currentparents] > 2} {
	set xt [expr {$xt + ([llength $currentparents] - 2) * $linespc}]
    }
    set rowtextx($lineno) $xt
    set marks {}
    set ntags 0
    if {[info exists idtags($id)]} {
	set marks $idtags($id)
	set ntags [llength $marks]
    }
    if {[info exists idheads($id)]} {
	set marks [concat $marks $idheads($id)]
    }
    if {$marks != {}} {
	set delta [expr {int(0.5 * ($linespc - $lthickness))}]
	set yt [expr $y1 - 0.5 * $linespc]
	set yb [expr $yt + $linespc - 1]
	set xvals {}
	set wvals {}
	foreach tag $marks {
	    set wid [font measure $mainfont $tag]
	    lappend xvals $xt
	    lappend wvals $wid
	    set xt [expr {$xt + $delta + $wid + $lthickness + $linespc}]
	}
	set t [$canv create line $x $y1 [lindex $xvals end] $y1 \
		   -width $lthickness -fill black]
	$canv lower $t
	foreach tag $marks x $xvals wid $wvals {
	    set xl [expr $x + $delta]
	    set xr [expr $x + $delta + $wid + $lthickness]
	    if {[incr ntags -1] >= 0} {
		# draw a tag
		$canv create polygon $x [expr $yt + $delta] $xl $yt\
		    $xr $yt $xr $yb $xl $yb $x [expr $yb - $delta] \
		    -width 1 -outline black -fill yellow
	    } else {
		# draw a head
		set xl [expr $xl - $delta/2]
		$canv create polygon $x $yt $xr $yt $xr $yb $x $yb \
		    -width 1 -outline black -fill green
	    }
	    $canv create text $xl $y1 -anchor w -text $tag \
		-font $mainfont
	}
    }
    set headline [lindex $commitinfo($id) 0]
    set name [lindex $commitinfo($id) 1]
    set date [lindex $commitinfo($id) 2]
    set linehtag($lineno) [$canv create text $xt $y1 -anchor w \
			       -text $headline -font $mainfont ]
    $canv bind $linehtag($lineno) <Button-3> "rowmenu %X %Y $id"
    set linentag($lineno) [$canv2 create text 3 $y1 -anchor w \
			       -text $name -font $namefont]
    set linedtag($lineno) [$canv3 create text 3 $y1 -anchor w \
			       -text $date -font $mainfont]
}

proc updatetodo {level noshortcut} {
    global currentparents ncleft todo
    global mainline oldlevel oldtodo oldnlines
    global canvx0 canvy linespc mainline
    global commitinfo

    set oldlevel $level
    set oldtodo $todo
    set oldnlines [llength $todo]
    if {!$noshortcut && [llength $currentparents] == 1} {
	set p [lindex $currentparents 0]
	if {$ncleft($p) == 1 && [lsearch -exact $todo $p] < 0} {
	    set ncleft($p) 0
	    set x [expr $canvx0 + $level * $linespc]
	    set y [expr $canvy - $linespc]
	    set mainline($p) [list $x $y]
	    set todo [lreplace $todo $level $level $p]
	    return 0
	}
    }

    set todo [lreplace $todo $level $level]
    set i $level
    foreach p $currentparents {
	incr ncleft($p) -1
	set k [lsearch -exact $todo $p]
	if {$k < 0} {
	    set todo [linsert $todo $i $p]
	    incr i
	}
    }
    return 1
}

proc notecrossings {id lo hi corner} {
    global oldtodo crossings cornercrossings

    for {set i $lo} {[incr i] < $hi} {} {
	set p [lindex $oldtodo $i]
	if {$p == {}} continue
	if {$i == $corner} {
	    if {![info exists cornercrossings($id)]
		|| [lsearch -exact $cornercrossings($id) $p] < 0} {
		lappend cornercrossings($id) $p
	    }
	    if {![info exists cornercrossings($p)]
		|| [lsearch -exact $cornercrossings($p) $id] < 0} {
		lappend cornercrossings($p) $id
	    }
	} else {
	    if {![info exists crossings($id)]
		|| [lsearch -exact $crossings($id) $p] < 0} {
		lappend crossings($id) $p
	    }
	    if {![info exists crossings($p)]
		|| [lsearch -exact $crossings($p) $id] < 0} {
		lappend crossings($p) $id
	    }
	}
    }
}

proc drawslants {} {
    global canv mainline sidelines canvx0 canvy linespc
    global oldlevel oldtodo todo currentparents dupparents
    global lthickness linespc canvy colormap

    set y1 [expr $canvy - $linespc]
    set y2 $canvy
    set i -1
    foreach id $oldtodo {
	incr i
	if {$id == {}} continue
	set xi [expr {$canvx0 + $i * $linespc}]
	if {$i == $oldlevel} {
	    foreach p $currentparents {
		set j [lsearch -exact $todo $p]
		set coords [list $xi $y1]
		set xj [expr {$canvx0 + $j * $linespc}]
		if {$j < $i - 1} {
		    lappend coords [expr $xj + $linespc] $y1
		    notecrossings $p $j $i [expr {$j + 1}]
		} elseif {$j > $i + 1} {
		    lappend coords [expr $xj - $linespc] $y1
		    notecrossings $p $i $j [expr {$j - 1}]
		}
		if {[lsearch -exact $dupparents $p] >= 0} {
		    # draw a double-width line to indicate the doubled parent
		    lappend coords $xj $y2
		    lappend sidelines($p) [list $coords 2]
		    if {![info exists mainline($p)]} {
			set mainline($p) [list $xj $y2]
		    }
		} else {
		    # normal case, no parent duplicated
		    if {![info exists mainline($p)]} {
			if {$i != $j} {
			    lappend coords $xj $y2
			}
			set mainline($p) $coords
		    } else {
			lappend coords $xj $y2
			lappend sidelines($p) [list $coords 1]
		    }
		}
	    }
	} elseif {[lindex $todo $i] != $id} {
	    set j [lsearch -exact $todo $id]
	    set xj [expr {$canvx0 + $j * $linespc}]
	    lappend mainline($id) $xi $y1 $xj $y2
	}
    }
}

proc decidenext {{noread 0}} {
    global parents children nchildren ncleft todo
    global canv canv2 canv3 mainfont namefont canvx0 canvy linespc
    global datemode cdate
    global commitinfo
    global currentparents oldlevel oldnlines oldtodo
    global lineno lthickness

    # remove the null entry if present
    set nullentry [lsearch -exact $todo {}]
    if {$nullentry >= 0} {
	set todo [lreplace $todo $nullentry $nullentry]
    }

    # choose which one to do next time around
    set todol [llength $todo]
    set level -1
    set latest {}
    for {set k $todol} {[incr k -1] >= 0} {} {
	set p [lindex $todo $k]
	if {$ncleft($p) == 0} {
	    if {$datemode} {
		if {![info exists commitinfo($p)]} {
		    if {$noread} {
			return {}
		    }
		    readcommit $p
		}
		if {$latest == {} || $cdate($p) > $latest} {
		    set level $k
		    set latest $cdate($p)
		}
	    } else {
		set level $k
		break
	    }
	}
    }
    if {$level < 0} {
	if {$todo != {}} {
	    puts "ERROR: none of the pending commits can be done yet:"
	    foreach p $todo {
		puts "  $p ($ncleft($p))"
	    }
	}
	return -1
    }

    # If we are reducing, put in a null entry
    if {$todol < $oldnlines} {
	if {$nullentry >= 0} {
	    set i $nullentry
	    while {$i < $todol
		   && [lindex $oldtodo $i] == [lindex $todo $i]} {
		incr i
	    }
	} else {
	    set i $oldlevel
	    if {$level >= $i} {
		incr i
	    }
	}
	if {$i < $todol} {
	    set todo [linsert $todo $i {}]
	    if {$level >= $i} {
		incr level
	    }
	}
    }
    return $level
}

proc drawcommit {id} {
    global phase todo nchildren datemode nextupdate
    global startcommits

    if {$phase != "incrdraw"} {
	set phase incrdraw
	set todo $id
	set startcommits $id
	initgraph
	drawcommitline 0
	updatetodo 0 $datemode
    } else {
	if {$nchildren($id) == 0} {
	    lappend todo $id
	    lappend startcommits $id
	}
	set level [decidenext 1]
	if {$level == {} || $id != [lindex $todo $level]} {
	    return
	}
	while 1 {
	    drawslants
	    drawcommitline $level
	    if {[updatetodo $level $datemode]} {
		set level [decidenext 1]
		if {$level == {}} break
	    }
	    set id [lindex $todo $level]
	    if {![info exists commitlisted($id)]} {
		break
	    }
	    if {[clock clicks -milliseconds] >= $nextupdate} {
		doupdate
		if {$stopped} break
	    }
	}
    }
}

proc finishcommits {} {
    global phase
    global startcommits
    global canv mainfont ctext maincursor textcursor

    if {$phase != "incrdraw"} {
	$canv delete all
	$canv create text 3 3 -anchor nw -text "No commits selected" \
	    -font $mainfont -tags textitems
	set phase {}
    } else {
	drawslants
	set level [decidenext]
	drawrest $level [llength $startcommits]
    }
    . config -cursor $maincursor
    $ctext config -cursor $textcursor
}

proc drawgraph {} {
    global nextupdate startmsecs startcommits todo

    if {$startcommits == {}} return
    set startmsecs [clock clicks -milliseconds]
    set nextupdate [expr $startmsecs + 100]
    initgraph
    set todo [lindex $startcommits 0]
    drawrest 0 1
}

proc drawrest {level startix} {
    global phase stopped redisplaying selectedline
    global datemode currentparents todo
    global numcommits
    global nextupdate startmsecs startcommits idline

    if {$level >= 0} {
	set phase drawgraph
	set startid [lindex $startcommits $startix]
	set startline -1
	if {$startid != {}} {
	    set startline $idline($startid)
	}
	while 1 {
	    if {$stopped} break
	    drawcommitline $level
	    set hard [updatetodo $level $datemode]
	    if {$numcommits == $startline} {
		lappend todo $startid
		set hard 1
		incr startix
		set startid [lindex $startcommits $startix]
		set startline -1
		if {$startid != {}} {
		    set startline $idline($startid)
		}
	    }
	    if {$hard} {
		set level [decidenext]
		if {$level < 0} break
		drawslants
	    }
	    if {[clock clicks -milliseconds] >= $nextupdate} {
		update
		incr nextupdate 100
	    }
	}
    }
    set phase {}
    set drawmsecs [expr [clock clicks -milliseconds] - $startmsecs]
    #puts "overall $drawmsecs ms for $numcommits commits"
    if {$redisplaying} {
	if {$stopped == 0 && [info exists selectedline]} {
	    selectline $selectedline
	}
	if {$stopped == 1} {
	    set stopped 0
	    after idle drawgraph
	} else {
	    set redisplaying 0
	}
    }
}

proc findmatches {f} {
    global findtype foundstring foundstrlen
    if {$findtype == "Regexp"} {
	set matches [regexp -indices -all -inline $foundstring $f]
    } else {
	if {$findtype == "IgnCase"} {
	    set str [string tolower $f]
	} else {
	    set str $f
	}
	set matches {}
	set i 0
	while {[set j [string first $foundstring $str $i]] >= 0} {
	    lappend matches [list $j [expr $j+$foundstrlen-1]]
	    set i [expr $j + $foundstrlen]
	}
    }
    return $matches
}

proc dofind {} {
    global findtype findloc findstring markedmatches commitinfo
    global numcommits lineid linehtag linentag linedtag
    global mainfont namefont canv canv2 canv3 selectedline
    global matchinglines foundstring foundstrlen
    unmarkmatches
    focus .
    set matchinglines {}
    set fldtypes {Headline Author Date Committer CDate Comment}
    if {$findtype == "IgnCase"} {
	set foundstring [string tolower $findstring]
    } else {
	set foundstring $findstring
    }
    set foundstrlen [string length $findstring]
    if {$foundstrlen == 0} return
    if {![info exists selectedline]} {
	set oldsel -1
    } else {
	set oldsel $selectedline
    }
    set didsel 0
    for {set l 0} {$l < $numcommits} {incr l} {
	set id $lineid($l)
	set info $commitinfo($id)
	set doesmatch 0
	foreach f $info ty $fldtypes {
	    if {$findloc != "All fields" && $findloc != $ty} {
		continue
	    }
	    set matches [findmatches $f]
	    if {$matches == {}} continue
	    set doesmatch 1
	    if {$ty == "Headline"} {
		markmatches $canv $l $f $linehtag($l) $matches $mainfont
	    } elseif {$ty == "Author"} {
		markmatches $canv2 $l $f $linentag($l) $matches $namefont
	    } elseif {$ty == "Date"} {
		markmatches $canv3 $l $f $linedtag($l) $matches $mainfont
	    }
	}
	if {$doesmatch} {
	    lappend matchinglines $l
	    if {!$didsel && $l > $oldsel} {
		findselectline $l
		set didsel 1
	    }
	}
    }
    if {$matchinglines == {}} {
	bell
    } elseif {!$didsel} {
	findselectline [lindex $matchinglines 0]
    }
}

proc findselectline {l} {
    global findloc commentend ctext
    selectline $l
    if {$findloc == "All fields" || $findloc == "Comments"} {
	# highlight the matches in the comments
	set f [$ctext get 1.0 $commentend]
	set matches [findmatches $f]
	foreach match $matches {
	    set start [lindex $match 0]
	    set end [expr [lindex $match 1] + 1]
	    $ctext tag add found "1.0 + $start c" "1.0 + $end c"
	}
    }
}

proc findnext {} {
    global matchinglines selectedline
    if {![info exists matchinglines]} {
	dofind
	return
    }
    if {![info exists selectedline]} return
    foreach l $matchinglines {
	if {$l > $selectedline} {
	    findselectline $l
	    return
	}
    }
    bell
}

proc findprev {} {
    global matchinglines selectedline
    if {![info exists matchinglines]} {
	dofind
	return
    }
    if {![info exists selectedline]} return
    set prev {}
    foreach l $matchinglines {
	if {$l >= $selectedline} break
	set prev $l
    }
    if {$prev != {}} {
	findselectline $prev
    } else {
	bell
    }
}

proc markmatches {canv l str tag matches font} {
    set bbox [$canv bbox $tag]
    set x0 [lindex $bbox 0]
    set y0 [lindex $bbox 1]
    set y1 [lindex $bbox 3]
    foreach match $matches {
	set start [lindex $match 0]
	set end [lindex $match 1]
	if {$start > $end} continue
	set xoff [font measure $font [string range $str 0 [expr $start-1]]]
	set xlen [font measure $font [string range $str 0 [expr $end]]]
	set t [$canv create rect [expr $x0+$xoff] $y0 [expr $x0+$xlen+2] $y1 \
		   -outline {} -tags matches -fill yellow]
	$canv lower $t
    }
}

proc unmarkmatches {} {
    global matchinglines
    allcanvs delete matches
    catch {unset matchinglines}
}

proc selcanvline {w x y} {
    global canv canvy0 ctext linespc selectedline
    global lineid linehtag linentag linedtag rowtextx
    set ymax [lindex [$canv cget -scrollregion] 3]
    if {$ymax == {}} return
    set yfrac [lindex [$canv yview] 0]
    set y [expr {$y + $yfrac * $ymax}]
    set l [expr {int(($y - $canvy0) / $linespc + 0.5)}]
    if {$l < 0} {
	set l 0
    }
    if {$w eq $canv} {
	if {![info exists rowtextx($l)] || $x < $rowtextx($l)} return
    }
    unmarkmatches
    selectline $l
}

proc selectline {l} {
    global canv canv2 canv3 ctext commitinfo selectedline
    global lineid linehtag linentag linedtag
    global canvy0 linespc parents nparents
    global cflist currentid sha1entry diffids
    global commentend seenfile idtags
    $canv delete hover
    if {![info exists lineid($l)] || ![info exists linehtag($l)]} return
    $canv delete secsel
    set t [eval $canv create rect [$canv bbox $linehtag($l)] -outline {{}} \
	       -tags secsel -fill [$canv cget -selectbackground]]
    $canv lower $t
    $canv2 delete secsel
    set t [eval $canv2 create rect [$canv2 bbox $linentag($l)] -outline {{}} \
	       -tags secsel -fill [$canv2 cget -selectbackground]]
    $canv2 lower $t
    $canv3 delete secsel
    set t [eval $canv3 create rect [$canv3 bbox $linedtag($l)] -outline {{}} \
	       -tags secsel -fill [$canv3 cget -selectbackground]]
    $canv3 lower $t
    set y [expr {$canvy0 + $l * $linespc}]
    set ymax [lindex [$canv cget -scrollregion] 3]
    set ytop [expr {$y - $linespc - 1}]
    set ybot [expr {$y + $linespc + 1}]
    set wnow [$canv yview]
    set wtop [expr [lindex $wnow 0] * $ymax]
    set wbot [expr [lindex $wnow 1] * $ymax]
    set wh [expr {$wbot - $wtop}]
    set newtop $wtop
    if {$ytop < $wtop} {
	if {$ybot < $wtop} {
	    set newtop [expr {$y - $wh / 2.0}]
	} else {
	    set newtop $ytop
	    if {$newtop > $wtop - $linespc} {
		set newtop [expr {$wtop - $linespc}]
	    }
	}
    } elseif {$ybot > $wbot} {
	if {$ytop > $wbot} {
	    set newtop [expr {$y - $wh / 2.0}]
	} else {
	    set newtop [expr {$ybot - $wh}]
	    if {$newtop < $wtop + $linespc} {
		set newtop [expr {$wtop + $linespc}]
	    }
	}
    }
    if {$newtop != $wtop} {
	if {$newtop < 0} {
	    set newtop 0
	}
	allcanvs yview moveto [expr $newtop * 1.0 / $ymax]
    }
    set selectedline $l

    set id $lineid($l)
    set currentid $id
    set diffids [concat $id $parents($id)]
    $sha1entry delete 0 end
    $sha1entry insert 0 $id
    $sha1entry selection from 0
    $sha1entry selection to end

    $ctext conf -state normal
    $ctext delete 0.0 end
    $ctext mark set fmark.0 0.0
    $ctext mark gravity fmark.0 left
    set info $commitinfo($id)
    $ctext insert end "Author: [lindex $info 1]  [lindex $info 2]\n"
    $ctext insert end "Committer: [lindex $info 3]  [lindex $info 4]\n"
    if {[info exists idtags($id)]} {
	$ctext insert end "Tags:"
	foreach tag $idtags($id) {
	    $ctext insert end " $tag"
	}
	$ctext insert end "\n"
    }
    $ctext insert end "\n"
    $ctext insert end [lindex $info 5]
    $ctext insert end "\n"
    $ctext tag delete Comments
    $ctext tag remove found 1.0 end
    $ctext conf -state disabled
    set commentend [$ctext index "end - 1c"]

    $cflist delete 0 end
    $cflist insert end "Comments"
    if {$nparents($id) == 1} {
	startdiff
    }
    catch {unset seenfile}
}

proc startdiff {} {
    global treediffs diffids treepending

    if {![info exists treediffs($diffids)]} {
	if {![info exists treepending]} {
	    gettreediffs $diffids
	}
    } else {
	addtocflist $diffids
    }
}

proc selnextline {dir} {
    global selectedline
    if {![info exists selectedline]} return
    set l [expr $selectedline + $dir]
    unmarkmatches
    selectline $l
}

proc addtocflist {ids} {
    global diffids treediffs cflist
    if {$ids != $diffids} {
	gettreediffs $diffids
	return
    }
    foreach f $treediffs($ids) {
	$cflist insert end $f
    }
    getblobdiffs $ids
}

proc gettreediffs {ids} {
    global treediffs parents treepending
    set treepending $ids
    set treediffs($ids) {}
    set id [lindex $ids 0]
    set p [lindex $ids 1]
    if [catch {set gdtf [open "|git-diff-tree -r $p $id" r]}] return
    fconfigure $gdtf -blocking 0
    fileevent $gdtf readable "gettreediffline $gdtf {$ids}"
}

proc gettreediffline {gdtf ids} {
    global treediffs treepending
    set n [gets $gdtf line]
    if {$n < 0} {
	if {![eof $gdtf]} return
	close $gdtf
	unset treepending
	addtocflist $ids
	return
    }
    set file [lindex $line 5]
    lappend treediffs($ids) $file
}

proc getblobdiffs {ids} {
    global diffopts blobdifffd env curdifftag curtagstart
    global diffindex difffilestart nextupdate

    set id [lindex $ids 0]
    set p [lindex $ids 1]
    set env(GIT_DIFF_OPTS) $diffopts
    if [catch {set bdf [open "|git-diff-tree -r -p $p $id" r]} err] {
	puts "error getting diffs: $err"
	return
    }
    fconfigure $bdf -blocking 0
    set blobdifffd($ids) $bdf
    set curdifftag Comments
    set curtagstart 0.0
    set diffindex 0
    catch {unset difffilestart}
    fileevent $bdf readable "getblobdiffline $bdf {$ids}"
    set nextupdate [expr {[clock clicks -milliseconds] + 100}]
}

proc getblobdiffline {bdf ids} {
    global diffids blobdifffd ctext curdifftag curtagstart seenfile
    global diffnexthead diffnextnote diffindex difffilestart
    global nextupdate

    set n [gets $bdf line]
    if {$n < 0} {
	if {[eof $bdf]} {
	    close $bdf
	    if {$ids == $diffids && $bdf == $blobdifffd($ids)} {
		$ctext tag add $curdifftag $curtagstart end
		set seenfile($curdifftag) 1
	    }
	}
	return
    }
    if {$ids != $diffids || $bdf != $blobdifffd($ids)} {
	return
    }
    $ctext conf -state normal
    if {[regexp {^---[ \t]+([^/])*/(.*)} $line match s1 fname]} {
	# start of a new file
	$ctext insert end "\n"
	$ctext tag add $curdifftag $curtagstart end
	set seenfile($curdifftag) 1
	set curtagstart [$ctext index "end - 1c"]
	set header $fname
	if {[info exists diffnexthead]} {
	    set fname $diffnexthead
	    set header "$diffnexthead ($diffnextnote)"
	    unset diffnexthead
	}
	set here [$ctext index "end - 1c"]
	set difffilestart($diffindex) $here
	incr diffindex
	# start mark names at fmark.1 for first file
	$ctext mark set fmark.$diffindex $here
	$ctext mark gravity fmark.$diffindex left
	set curdifftag "f:$fname"
	$ctext tag delete $curdifftag
	set l [expr {(78 - [string length $header]) / 2}]
	set pad [string range "----------------------------------------" 1 $l]
	$ctext insert end "$pad $header $pad\n" filesep
    } elseif {[string range $line 0 2] == "+++"} {
	# no need to do anything with this
    } elseif {[regexp {^Created: (.*) \((mode: *[0-7]*)\)} $line match fn m]} {
	set diffnexthead $fn
	set diffnextnote "created, mode $m"
    } elseif {[string range $line 0 8] == "Deleted: "} {
	set diffnexthead [string range $line 9 end]
	set diffnextnote "deleted"
    } elseif {[regexp {^diff --git a/(.*) b/} $line match fn]} {
	# save the filename in case the next thing is "new file mode ..."
	set diffnexthead $fn
	set diffnextnote "modified"
    } elseif {[regexp {^new file mode ([0-7]+)} $line match m]} {
	set diffnextnote "new file, mode $m"
    } elseif {[string range $line 0 11] == "deleted file"} {
	set diffnextnote "deleted"
    } elseif {[regexp {^@@ -([0-9]+),([0-9]+) \+([0-9]+),([0-9]+) @@(.*)} \
		   $line match f1l f1c f2l f2c rest]} {
	$ctext insert end "\t" hunksep
	$ctext insert end "    $f1l    " d0 "    $f2l    " d1
	$ctext insert end "    $rest \n" hunksep
    } else {
	set x [string range $line 0 0]
	if {$x == "-" || $x == "+"} {
	    set tag [expr {$x == "+"}]
	    set line [string range $line 1 end]
	    $ctext insert end "$line\n" d$tag
	} elseif {$x == " "} {
	    set line [string range $line 1 end]
	    $ctext insert end "$line\n"
	} elseif {$x == "\\"} {
	    # e.g. "\ No newline at end of file"
	    $ctext insert end "$line\n" filesep
	} else {
	    # Something else we don't recognize
	    if {$curdifftag != "Comments"} {
		$ctext insert end "\n"
		$ctext tag add $curdifftag $curtagstart end
		set seenfile($curdifftag) 1
		set curtagstart [$ctext index "end - 1c"]
		set curdifftag Comments
	    }
	    $ctext insert end "$line\n" filesep
	}
    }
    $ctext conf -state disabled
    if {[clock clicks -milliseconds] >= $nextupdate} {
	incr nextupdate 100
	fileevent $bdf readable {}
	update
	fileevent $bdf readable "getblobdiffline $bdf {$ids}"
    }
}

proc nextfile {} {
    global difffilestart ctext
    set here [$ctext index @0,0]
    for {set i 0} {[info exists difffilestart($i)]} {incr i} {
	if {[$ctext compare $difffilestart($i) > $here]} {
	    $ctext yview $difffilestart($i)
	    break
	}
    }
}

proc listboxsel {} {
    global ctext cflist currentid treediffs seenfile
    if {![info exists currentid]} return
    set sel [lsort [$cflist curselection]]
    if {$sel eq {}} return
    set first [lindex $sel 0]
    catch {$ctext yview fmark.$first}
}

proc setcoords {} {
    global linespc charspc canvx0 canvy0 mainfont
    set linespc [font metrics $mainfont -linespace]
    set charspc [font measure $mainfont "m"]
    set canvy0 [expr 3 + 0.5 * $linespc]
    set canvx0 [expr 3 + 0.5 * $linespc]
}

proc redisplay {} {
    global selectedline stopped redisplaying phase
    if {$stopped > 1} return
    if {$phase == "getcommits"} return
    set redisplaying 1
    if {$phase == "drawgraph" || $phase == "incrdraw"} {
	set stopped 1
    } else {
	drawgraph
    }
}

proc incrfont {inc} {
    global mainfont namefont textfont selectedline ctext canv phase
    global stopped entries
    unmarkmatches
    set mainfont [lreplace $mainfont 1 1 [expr {[lindex $mainfont 1] + $inc}]]
    set namefont [lreplace $namefont 1 1 [expr {[lindex $namefont 1] + $inc}]]
    set textfont [lreplace $textfont 1 1 [expr {[lindex $textfont 1] + $inc}]]
    setcoords
    $ctext conf -font $textfont
    $ctext tag conf filesep -font [concat $textfont bold]
    foreach e $entries {
	$e conf -font $mainfont
    }
    if {$phase == "getcommits"} {
	$canv itemconf textitems -font $mainfont
    }
    redisplay
}

proc clearsha1 {} {
    global sha1entry sha1string
    if {[string length $sha1string] == 40} {
	$sha1entry delete 0 end
    }
}

proc sha1change {n1 n2 op} {
    global sha1string currentid sha1but
    if {$sha1string == {}
	|| ([info exists currentid] && $sha1string == $currentid)} {
	set state disabled
    } else {
	set state normal
    }
    if {[$sha1but cget -state] == $state} return
    if {$state == "normal"} {
	$sha1but conf -state normal -relief raised -text "Goto: "
    } else {
	$sha1but conf -state disabled -relief flat -text "SHA1 ID: "
    }
}

proc gotocommit {} {
    global sha1string currentid idline tagids
    if {$sha1string == {}
	|| ([info exists currentid] && $sha1string == $currentid)} return
    if {[info exists tagids($sha1string)]} {
	set id $tagids($sha1string)
    } else {
	set id [string tolower $sha1string]
    }
    if {[info exists idline($id)]} {
	selectline $idline($id)
	return
    }
    if {[regexp {^[0-9a-fA-F]{40}$} $sha1string]} {
	set type "SHA1 id"
    } else {
	set type "Tag"
    }
    error_popup "$type $sha1string is not known"
}

proc lineenter {x y id} {
    global hoverx hovery hoverid hovertimer
    global commitinfo canv

    if {![info exists commitinfo($id)]} return
    set hoverx $x
    set hovery $y
    set hoverid $id
    if {[info exists hovertimer]} {
	after cancel $hovertimer
    }
    set hovertimer [after 500 linehover]
    $canv delete hover
}

proc linemotion {x y id} {
    global hoverx hovery hoverid hovertimer

    if {[info exists hoverid] && $id == $hoverid} {
	set hoverx $x
	set hovery $y
	if {[info exists hovertimer]} {
	    after cancel $hovertimer
	}
	set hovertimer [after 500 linehover]
    }
}

proc lineleave {id} {
    global hoverid hovertimer canv

    if {[info exists hoverid] && $id == $hoverid} {
	$canv delete hover
	if {[info exists hovertimer]} {
	    after cancel $hovertimer
	    unset hovertimer
	}
	unset hoverid
    }
}

proc linehover {} {
    global hoverx hovery hoverid hovertimer
    global canv linespc lthickness
    global commitinfo mainfont

    set text [lindex $commitinfo($hoverid) 0]
    set ymax [lindex [$canv cget -scrollregion] 3]
    if {$ymax == {}} return
    set yfrac [lindex [$canv yview] 0]
    set x [expr {$hoverx + 2 * $linespc}]
    set y [expr {$hovery + $yfrac * $ymax - $linespc / 2}]
    set x0 [expr {$x - 2 * $lthickness}]
    set y0 [expr {$y - 2 * $lthickness}]
    set x1 [expr {$x + [font measure $mainfont $text] + 2 * $lthickness}]
    set y1 [expr {$y + $linespc + 2 * $lthickness}]
    set t [$canv create rectangle $x0 $y0 $x1 $y1 \
	       -fill \#ffff80 -outline black -width 1 -tags hover]
    $canv raise $t
    set t [$canv create text $x $y -anchor nw -text $text -tags hover]
    $canv raise $t
}

proc lineclick {x y id} {
    global ctext commitinfo children cflist canv

    unmarkmatches
    $canv delete hover
    # fill the details pane with info about this line
    $ctext conf -state normal
    $ctext delete 0.0 end
    $ctext insert end "Parent:\n "
    catch {destroy $ctext.$id}
    button $ctext.$id -text "Go:" -command "selbyid $id" \
	-padx 4 -pady 0
    $ctext window create end -window $ctext.$id -align center
    set info $commitinfo($id)
    $ctext insert end "\t[lindex $info 0]\n"
    $ctext insert end "\tAuthor:\t[lindex $info 1]\n"
    $ctext insert end "\tDate:\t[lindex $info 2]\n"
    $ctext insert end "\tID:\t$id\n"
    if {[info exists children($id)]} {
	$ctext insert end "\nChildren:"
	foreach child $children($id) {
	    $ctext insert end "\n "
	    catch {destroy $ctext.$child}
	    button $ctext.$child -text "Go:" -command "selbyid $child" \
		-padx 4 -pady 0
	    $ctext window create end -window $ctext.$child -align center
	    set info $commitinfo($child)
	    $ctext insert end "\t[lindex $info 0]"
	}
    }
    $ctext conf -state disabled

    $cflist delete 0 end
}

proc selbyid {id} {
    global idline
    if {[info exists idline($id)]} {
	selectline $idline($id)
    }
}

proc mstime {} {
    global startmstime
    if {![info exists startmstime]} {
	set startmstime [clock clicks -milliseconds]
    }
    return [format "%.3f" [expr {([clock click -milliseconds] - $startmstime) / 1000.0}]]
}

proc rowmenu {x y id} {
    global rowctxmenu idline selectedline rowmenuid

    if {![info exists selectedline] || $idline($id) eq $selectedline} {
	set state disabled
    } else {
	set state normal
    }
    $rowctxmenu entryconfigure 0 -state $state
    $rowctxmenu entryconfigure 1 -state $state
    set rowmenuid $id
    tk_popup $rowctxmenu $x $y
}

proc diffvssel {dirn} {
    global rowmenuid selectedline lineid
    global ctext cflist
    global diffids commitinfo

    if {![info exists selectedline]} return
    if {$dirn} {
	set oldid $lineid($selectedline)
	set newid $rowmenuid
    } else {
	set oldid $rowmenuid
	set newid $lineid($selectedline)
    }
    $ctext conf -state normal
    $ctext delete 0.0 end
    $ctext mark set fmark.0 0.0
    $ctext mark gravity fmark.0 left
    $cflist delete 0 end
    $cflist insert end "Top"
    $ctext insert end "From $oldid\n     "
    $ctext insert end [lindex $commitinfo($oldid) 0]
    $ctext insert end "\n\nTo   $newid\n     "
    $ctext insert end [lindex $commitinfo($newid) 0]
    $ctext insert end "\n"
    $ctext conf -state disabled
    $ctext tag delete Comments
    $ctext tag remove found 1.0 end
    set diffids [list $newid $oldid]
    startdiff
}

proc doquit {} {
    global stopped
    set stopped 100
    destroy .
}

# defaults...
set datemode 0
set boldnames 0
set diffopts "-U 5 -p"

set mainfont {Helvetica 9}
set textfont {Courier 9}

set colors {green red blue magenta darkgrey brown orange}

catch {source ~/.gitk}

set namefont $mainfont
if {$boldnames} {
    lappend namefont bold
}

set revtreeargs {}
foreach arg $argv {
    switch -regexp -- $arg {
	"^$" { }
	"^-b" { set boldnames 1 }
	"^-d" { set datemode 1 }
	default {
	    lappend revtreeargs $arg
	}
    }
}

set stopped 0
set redisplaying 0
set stuffsaved 0
setcoords
makewindow
readrefs
getcommits $revtreeargs