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

# 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 gitdir {} {
    global env
    if {[info exists env(GIT_DIR)]} {
	return $env(GIT_DIR)
    } else {
	return ".git"
    }
}

proc parse_args {rargs} {
    global parsed_args

    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
    }
    return $parsed_args
}

proc start_rev_list {rlargs} {
    global startmsecs nextupdate ncmupdate
    global commfd leftover tclencoding datemode

    set startmsecs [clock clicks -milliseconds]
    set nextupdate [expr {$startmsecs + 100}]
    set ncmupdate 1
    initlayout
    set order "--topo-order"
    if {$datemode} {
	set order "--date-order"
    }
    if {[catch {
	set commfd [open [concat | git-rev-list --header $order \
			      --parents --boundary $rlargs] r]
    } err]} {
	puts stderr "Error executing git-rev-list: $err"
	exit 1
    }
    set leftover {}
    fconfigure $commfd -blocking 0 -translation lf
    if {$tclencoding != {}} {
	fconfigure $commfd -encoding $tclencoding
    }
    fileevent $commfd readable [list getcommitlines $commfd]
    . config -cursor watch
    settextcursor watch
}

proc getcommits {rargs} {
    global phase canv mainfont

    set phase getcommits
    start_rev_list [parse_args $rargs]
    $canv delete all
    $canv create text 3 3 -anchor nw -text "Reading commits..." \
	-font $mainfont -tags textitems
}

proc getcommitlines {commfd}  {
    global commitlisted nextupdate
    global leftover
    global displayorder commitidx commitrow commitdata
    global parentlist childlist children

    set stuff [read $commfd]
    if {$stuff == {}} {
	if {![eof $commfd]} return
	# set it blocking so we wait for the process to terminate
	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
    set gotsome 0
    while 1 {
	set i [string first "\0" $stuff $start]
	if {$i < 0} {
	    append leftover [string range $stuff $start end]
	    break
	}
	if {$start == 0} {
	    set cmit $leftover
	    append cmit [string range $stuff 0 [expr {$i - 1}]]
	    set leftover {}
	} else {
	    set cmit [string range $stuff $start [expr {$i - 1}]]
	}
	set start [expr {$i + 1}]
	set j [string first "\n" $cmit]
	set ok 0
	set listed 1
	if {$j >= 0} {
	    set ids [string range $cmit 0 [expr {$j - 1}]]
	    if {[string range $ids 0 0] == "-"} {
		set listed 0
		set ids [string range $ids 1 end]
	    }
	    set ok 1
	    foreach id $ids {
		if {[string length $id] != 40} {
		    set ok 0
		    break
		}
	    }
	}
	if {!$ok} {
	    set shortcmit $cmit
	    if {[string length $shortcmit] > 80} {
		set shortcmit "[string range $shortcmit 0 80]..."
	    }
	    error_popup "Can't parse git-rev-list output: {$shortcmit}"
	    exit 1
	}
	set id [lindex $ids 0]
	if {$listed} {
	    set olds [lrange $ids 1 end]
	    if {[llength $olds] > 1} {
		set olds [lsort -unique $olds]
	    }
	    foreach p $olds {
		lappend children($p) $id
	    }
	} else {
	    set olds {}
	}
	lappend parentlist $olds
	if {[info exists children($id)]} {
	    lappend childlist $children($id)
	} else {
	    lappend childlist {}
	}
	set commitdata($id) [string range $cmit [expr {$j + 1}] end]
	set commitrow($id) $commitidx
	incr commitidx
	lappend displayorder $id
	lappend commitlisted $listed
	set gotsome 1
    }
    if {$gotsome} {
	layoutmore
    }
    if {[clock clicks -milliseconds] >= $nextupdate} {
	doupdate 1
    }
}

proc doupdate {reading} {
    global commfd nextupdate numcommits ncmupdate

    if {$reading} {
	fileevent $commfd readable {}
    }
    update
    set nextupdate [expr {[clock clicks -milliseconds] + 100}]
    if {$numcommits < 100} {
	set ncmupdate [expr {$numcommits + 1}]
    } elseif {$numcommits < 10000} {
	set ncmupdate [expr {$numcommits + 10}]
    } else {
	set ncmupdate [expr {$numcommits + 100}]
    }
    if {$reading} {
	fileevent $commfd readable [list getcommitlines $commfd]
    }
}

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

proc updatecommits {rargs} {
    stopfindproc
    foreach v {colormap selectedline matchinglines treediffs
	mergefilelist currentid rowtextx commitrow
	rowidlist rowoffsets idrowranges idrangedrawn iddrawn
	linesegends crossings cornercrossings} {
	global $v
	catch {unset $v}
    }
    allcanvs delete all
    readrefs
    getcommits $rargs
}

proc parsecommit {id contents listed} {
    global commitinfo cdate

    set inhdr 1
    set comment {}
    set headline {}
    set auname {}
    set audate {}
    set comname {}
    set comdate {}
    set hdrend [string first "\n\n" $contents]
    if {$hdrend < 0} {
	# should never happen...
	set hdrend [string length $contents]
    }
    set header [string range $contents 0 [expr {$hdrend - 1}]]
    set comment [string range $contents [expr {$hdrend + 2}] end]
    foreach line [split $header "\n"] {
	set tag [lindex $line 0]
	if {$tag == "author"} {
	    set audate [lindex $line end-1]
	    set auname [lrange $line 1 end-2]
	} elseif {$tag == "committer"} {
	    set comdate [lindex $line end-1]
	    set comname [lrange $line 1 end-2]
	}
    }
    set headline {}
    # take the first line of the comment as the headline
    set i [string first "\n" $comment]
    if {$i >= 0} {
	set headline [string trim [string range $comment 0 $i]]
    } else {
	set headline $comment
    }
    if {!$listed} {
	# git-rev-list indents the comment by 4 spaces;
	# if we got this via git-cat-file, add the indentation
	set newcomment {}
	foreach line [split $comment "\n"] {
	    append newcomment "    "
	    append newcomment $line
	    append newcomment "\n"
	}
	set comment $newcomment
    }
    if {$comdate != {}} {
	set cdate($id) $comdate
    }
    set commitinfo($id) [list $headline $auname $audate \
			     $comname $comdate $comment]
}

proc getcommit {id} {
    global commitdata commitinfo

    if {[info exists commitdata($id)]} {
	parsecommit $id $commitdata($id) 1
    } else {
	readcommit $id
	if {![info exists commitinfo($id)]} {
	    set commitinfo($id) {"No commit information available"}
	}
    }
    return 1
}

proc readrefs {} {
    global tagids idtags headids idheads tagcontents
    global otherrefids idotherrefs

    foreach v {tagids idtags headids idheads otherrefids idotherrefs} {
	catch {unset $v}
    }
    set refd [open [list | git ls-remote [gitdir]] r]
    while {0 <= [set n [gets $refd line]]} {
	if {![regexp {^([0-9a-f]{40})	refs/([^^]*)$} $line \
	    match id path]} {
	    continue
	}
	if {![regexp {^(tags|heads)/(.*)$} $path match type name]} {
	    set type others
	    set name $path
	}
	if {$type == "tags"} {
	    set tagids($name) $id
	    lappend idtags($id) $name
	    set obj {}
	    set type {}
	    set tag {}
	    catch {
		set commit [exec git-rev-parse "$id^0"]
		if {"$commit" != "$id"} {
		    set tagids($name) $commit
		    lappend idtags($commit) $name
		}
	    }		
	    catch {
	        set tagcontents($name) [exec git-cat-file tag "$id"]
	    }
	} elseif { $type == "heads" } {
	    set headids($name) $id
	    lappend idheads($id) $name
	} else {
	    set otherrefids($name) $id
	    lappend idotherrefs($id) $name
	}
    }
    close $refd
}

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"
    bind $w <Key-Return> "destroy $w"
    tkwait window $w
}

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

    menu .bar
    .bar add cascade -label "File" -menu .bar.file
    .bar configure -font $uifont
    menu .bar.file
    .bar.file add command -label "Update" -command [list updatecommits $rargs]
    .bar.file add command -label "Reread references" -command rereadrefs
    .bar.file add command -label "Quit" -command doquit
    .bar.file configure -font $uifont
    menu .bar.edit
    .bar add cascade -label "Edit" -menu .bar.edit
    .bar.edit add command -label "Preferences" -command doprefs
    .bar.edit configure -font $uifont
    menu .bar.help
    .bar add cascade -label "Help" -menu .bar.help
    .bar.help add command -label "About gitk" -command about
    .bar.help add command -label "Key bindings" -command keys
    .bar.help configure -font $uifont
    . 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 "scrollcanv $cscroll"
    .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 -font $uifont
    $sha1but conf -disabledforeground [$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

    image create bitmap bm-left -data {
	#define left_width 16
	#define left_height 16
	static unsigned char left_bits[] = {
	0x00, 0x00, 0xc0, 0x01, 0xe0, 0x00, 0x70, 0x00, 0x38, 0x00, 0x1c, 0x00,
	0x0e, 0x00, 0xff, 0x7f, 0xff, 0x7f, 0xff, 0x7f, 0x0e, 0x00, 0x1c, 0x00,
	0x38, 0x00, 0x70, 0x00, 0xe0, 0x00, 0xc0, 0x01};
    }
    image create bitmap bm-right -data {
	#define right_width 16
	#define right_height 16
	static unsigned char right_bits[] = {
	0x00, 0x00, 0xc0, 0x01, 0x80, 0x03, 0x00, 0x07, 0x00, 0x0e, 0x00, 0x1c,
	0x00, 0x38, 0xff, 0x7f, 0xff, 0x7f, 0xff, 0x7f, 0x00, 0x38, 0x00, 0x1c,
	0x00, 0x0e, 0x00, 0x07, 0x80, 0x03, 0xc0, 0x01};
    }
    button .ctop.top.bar.leftbut -image bm-left -command goback \
	-state disabled -width 26
    pack .ctop.top.bar.leftbut -side left -fill y
    button .ctop.top.bar.rightbut -image bm-right -command goforw \
	-state disabled -width 26
    pack .ctop.top.bar.rightbut -side left -fill y

    button .ctop.top.bar.findbut -text "Find" -command dofind -font $uifont
    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 -font $textfont
    pack $fstring -side left -expand 1 -fill x
    set findtype Exact
    set findtypemenu [tk_optionMenu .ctop.top.bar.findtype \
			  findtype Exact IgnCase Regexp]
    .ctop.top.bar.findtype configure -font $uifont
    .ctop.top.bar.findtype.menu configure -font $uifont
    set findloc "All fields"
    tk_optionMenu .ctop.top.bar.findloc findloc "All fields" Headline \
	Comments Author Committer Files Pickaxe
    .ctop.top.bar.findloc configure -font $uifont
    .ctop.top.bar.findloc.menu configure -font $uifont

    pack .ctop.top.bar.findloc -side right
    pack .ctop.top.bar.findtype -side right
    # for making sure type==Exact whenever loc==Pickaxe
    trace add variable findloc write findlocchange

    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 $geometry(ctexth) \
	-yscrollcommand ".ctop.cdet.left.sb set" -wrap none
    scrollbar .ctop.cdet.left.sb -command "$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] -back "#aaaaaa"
    $ctext tag conf hunksep -fore blue
    $ctext tag conf d0 -fore red
    $ctext tag conf d1 -fore "#00a000"
    $ctext tag conf m0 -fore red
    $ctext tag conf m1 -fore blue
    $ctext tag conf m2 -fore green
    $ctext tag conf m3 -fore purple
    $ctext tag conf m4 -fore brown
    $ctext tag conf m5 -fore "#009090"
    $ctext tag conf m6 -fore magenta
    $ctext tag conf m7 -fore "#808000"
    $ctext tag conf m8 -fore "#009000"
    $ctext tag conf m9 -fore "#ff0080"
    $ctext tag conf m10 -fore cyan
    $ctext tag conf m11 -fore "#b07070"
    $ctext tag conf m12 -fore "#70b0f0"
    $ctext tag conf m13 -fore "#70f0b0"
    $ctext tag conf m14 -fore "#f0b070"
    $ctext tag conf m15 -fore "#ff70b0"
    $ctext tag conf mmax -fore darkgrey
    set mergemax 16
    $ctext tag conf mresult -font [concat $textfont bold]
    $ctext tag conf msep -font [concat $textfont bold]
    $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" -font $mainfont
    scrollbar .ctop.cdet.right.sb -command "$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> "canvscan mark %W %x %y"
    bindall <B2-Motion> "canvscan dragto %W %x %y"
    bindkey <Home> selfirstline
    bindkey <End> sellastline
    bind . <Key-Up> "selnextline -1"
    bind . <Key-Down> "selnextline 1"
    bindkey <Key-Right> "goforw"
    bindkey <Key-Left> "goback"
    bind . <Key-Prior> "selnextpage -1"
    bind . <Key-Next> "selnextpage 1"
    bind . <Control-Home> "allcanvs yview moveto 0.0"
    bind . <Control-End> "allcanvs yview moveto 1.0"
    bind . <Control-Key-Up> "allcanvs yview scroll -1 units"
    bind . <Control-Key-Down> "allcanvs yview scroll 1 units"
    bind . <Control-Key-Prior> "allcanvs yview scroll -1 pages"
    bind . <Control-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> "$ctext yview scroll 1 pages"
    bindkey p "selnextline -1"
    bindkey n "selnextline 1"
    bindkey z "goback"
    bindkey x "goforw"
    bindkey i "selnextline -1"
    bindkey k "selnextline 1"
    bindkey j "goback"
    bindkey l "goforw"
    bindkey b "$ctext yview scroll -1 pages"
    bindkey d "$ctext yview scroll 18 units"
    bindkey u "$ctext yview scroll -18 units"
    bindkey / {findnext 1}
    bindkey <Key-Return> {findnext 0}
    bindkey ? findprev
    bindkey f nextfile
    bind . <Control-q> doquit
    bind . <Control-f> dofind
    bind . <Control-g> {findnext 0}
    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 curtextcursor $textcursor

    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}
    $rowctxmenu add command -label "Make patch" -command mkpatch
    $rowctxmenu add command -label "Create tag" -command mktag
    $rowctxmenu add command -label "Write commit to file" -command writecommit
}

# mouse-2 makes all windows scan vertically, but only the one
# the cursor is in scans horizontally
proc canvscan {op w x y} {
    global canv canv2 canv3
    foreach c [list $canv $canv2 $canv3] {
	if {$c == $w} {
	    $c scan $op $x $y
	} else {
	    $c scan $op 0 $y
	}
    }
}

proc scrollcanv {cscroll f0 f1} {
    $cscroll set $f0 $f1
    drawfrac $f0 $f1
}

# 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 uifont
    global stuffsaved findmergefiles maxgraphpct
    global maxwidth

    if {$stuffsaved} return
    if {![winfo viewable .]} return
    catch {
	set f [open "~/.gitk-new" w]
	puts $f [list set mainfont $mainfont]
	puts $f [list set textfont $textfont]
	puts $f [list set uifont $uifont]
	puts $f [list set findmergefiles $findmergefiles]
	puts $f [list set maxgraphpct $maxgraphpct]
	puts $f [list set maxwidth $maxwidth]
	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 - a commit viewer for git

Copyright © 2005-2006 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 keys {} {
    set w .keys
    if {[winfo exists $w]} {
	raise $w
	return
    }
    toplevel $w
    wm title $w "Gitk key bindings"
    message $w.m -text {
Gitk key bindings:

<Ctrl-Q>		Quit
<Home>		Move to first commit
<End>		Move to last commit
<Up>, p, i	Move up one commit
<Down>, n, k	Move down one commit
<Left>, z, j	Go back in history list
<Right>, x, l	Go forward in history list
<PageUp>	Move up one page in commit list
<PageDown>	Move down one page in commit list
<Ctrl-Home>	Scroll to top of commit list
<Ctrl-End>	Scroll to bottom of commit list
<Ctrl-Up>	Scroll commit list up one line
<Ctrl-Down>	Scroll commit list down one line
<Ctrl-PageUp>	Scroll commit list up one page
<Ctrl-PageDown>	Scroll commit list down one page
<Delete>, b	Scroll diff view up one page
<Backspace>	Scroll diff view up one page
<Space>		Scroll diff view down one page
u		Scroll diff view up 18 lines
d		Scroll diff view down 18 lines
<Ctrl-F>		Find
<Ctrl-G>		Move to next find hit
<Ctrl-R>		Move to previous find hit
<Return>	Move to next find hit
/		Move to next find hit, or redo find
?		Move to previous find hit
f		Scroll diff view to next file
<Ctrl-KP+>	Increase font size
<Ctrl-plus>	Increase font size
<Ctrl-KP->	Decrease font size
<Ctrl-minus>	Decrease font size
} \
	    -justify left -bg white -border 2 -relief sunken
    pack $w.m -side top -fill both
    button $w.ok -text Close -command "destroy $w"
    pack $w.ok -side bottom
}

proc shortids {ids} {
    set res {}
    foreach id $ids {
	if {[llength $id] > 1} {
	    lappend res [shortids $id]
	} elseif {[regexp {^[0-9a-f]{40}$} $id]} {
	    lappend res [string range $id 0 7]
	} else {
	    lappend res $id
	}
    }
    return $res
}

proc incrange {l x o} {
    set n [llength $l]
    while {$x < $n} {
	set e [lindex $l $x]
	if {$e ne {}} {
	    lset l $x [expr {$e + $o}]
	}
	incr x
    }
    return $l
}

proc ntimes {n o} {
    set ret {}
    for {} {$n > 0} {incr n -1} {
	lappend ret $o
    }
    return $ret
}

proc usedinrange {id l1 l2} {
    global children commitrow

    if {[info exists commitrow($id)]} {
	set r $commitrow($id)
	if {$l1 <= $r && $r <= $l2} {
	    return [expr {$r - $l1 + 1}]
	}
    }
    foreach c $children($id) {
	if {[info exists commitrow($c)]} {
	    set r $commitrow($c)
	    if {$l1 <= $r && $r <= $l2} {
		return [expr {$r - $l1 + 1}]
	    }
	}
    }
    return 0
}

proc sanity {row {full 0}} {
    global rowidlist rowoffsets

    set col -1
    set ids [lindex $rowidlist $row]
    foreach id $ids {
	incr col
	if {$id eq {}} continue
	if {$col < [llength $ids] - 1 &&
	    [lsearch -exact -start [expr {$col+1}] $ids $id] >= 0} {
	    puts "oops: [shortids $id] repeated in row $row col $col: {[shortids [lindex $rowidlist $row]]}"
	}
	set o [lindex $rowoffsets $row $col]
	set y $row
	set x $col
	while {$o ne {}} {
	    incr y -1
	    incr x $o
	    if {[lindex $rowidlist $y $x] != $id} {
		puts "oops: rowoffsets wrong at row [expr {$y+1}] col [expr {$x-$o}]"
		puts "  id=[shortids $id] check started at row $row"
		for {set i $row} {$i >= $y} {incr i -1} {
		    puts "  row $i ids={[shortids [lindex $rowidlist $i]]} offs={[lindex $rowoffsets $i]}"
		}
		break
	    }
	    if {!$full} break
	    set o [lindex $rowoffsets $y $x]
	}
    }
}

proc makeuparrow {oid x y z} {
    global rowidlist rowoffsets uparrowlen idrowranges

    for {set i 1} {$i < $uparrowlen && $y > 1} {incr i} {
	incr y -1
	incr x $z
	set off0 [lindex $rowoffsets $y]
	for {set x0 $x} {1} {incr x0} {
	    if {$x0 >= [llength $off0]} {
		set x0 [llength [lindex $rowoffsets [expr {$y-1}]]]
		break
	    }
	    set z [lindex $off0 $x0]
	    if {$z ne {}} {
		incr x0 $z
		break
	    }
	}
	set z [expr {$x0 - $x}]
	lset rowidlist $y [linsert [lindex $rowidlist $y] $x $oid]
	lset rowoffsets $y [linsert [lindex $rowoffsets $y] $x $z]
    }
    set tmp [lreplace [lindex $rowoffsets $y] $x $x {}]
    lset rowoffsets $y [incrange $tmp [expr {$x+1}] -1]
    lappend idrowranges($oid) $y
}

proc initlayout {} {
    global rowidlist rowoffsets displayorder commitlisted
    global rowlaidout rowoptim
    global idinlist rowchk
    global commitidx numcommits canvxmax canv
    global nextcolor
    global parentlist childlist children

    set commitidx 0
    set numcommits 0
    set displayorder {}
    set commitlisted {}
    set parentlist {}
    set childlist {}
    catch {unset children}
    set nextcolor 0
    set rowidlist {{}}
    set rowoffsets {{}}
    catch {unset idinlist}
    catch {unset rowchk}
    set rowlaidout 0
    set rowoptim 0
    set canvxmax [$canv cget -width]
}

proc setcanvscroll {} {
    global canv canv2 canv3 numcommits linespc canvxmax canvy0

    set ymax [expr {$canvy0 + ($numcommits - 0.5) * $linespc + 2}]
    $canv conf -scrollregion [list 0 0 $canvxmax $ymax]
    $canv2 conf -scrollregion [list 0 0 0 $ymax]
    $canv3 conf -scrollregion [list 0 0 0 $ymax]
}

proc visiblerows {} {
    global canv numcommits linespc

    set ymax [lindex [$canv cget -scrollregion] 3]
    if {$ymax eq {} || $ymax == 0} return
    set f [$canv yview]
    set y0 [expr {int([lindex $f 0] * $ymax)}]
    set r0 [expr {int(($y0 - 3) / $linespc) - 1}]
    if {$r0 < 0} {
	set r0 0
    }
    set y1 [expr {int([lindex $f 1] * $ymax)}]
    set r1 [expr {int(($y1 - 3) / $linespc) + 1}]
    if {$r1 >= $numcommits} {
	set r1 [expr {$numcommits - 1}]
    }
    return [list $r0 $r1]
}

proc layoutmore {} {
    global rowlaidout rowoptim commitidx numcommits optim_delay
    global uparrowlen

    set row $rowlaidout
    set rowlaidout [layoutrows $row $commitidx 0]
    set orow [expr {$rowlaidout - $uparrowlen - 1}]
    if {$orow > $rowoptim} {
	checkcrossings $rowoptim $orow
	optimize_rows $rowoptim 0 $orow
	set rowoptim $orow
    }
    set canshow [expr {$rowoptim - $optim_delay}]
    if {$canshow > $numcommits} {
	showstuff $canshow
    }
}

proc showstuff {canshow} {
    global numcommits
    global linesegends idrowranges idrangedrawn

    if {$numcommits == 0} {
	global phase
	set phase "incrdraw"
	allcanvs delete all
    }
    set row $numcommits
    set numcommits $canshow
    setcanvscroll
    set rows [visiblerows]
    set r0 [lindex $rows 0]
    set r1 [lindex $rows 1]
    for {set r $row} {$r < $canshow} {incr r} {
	if {[info exists linesegends($r)]} {
	    foreach id $linesegends($r) {
		set i -1
		foreach {s e} $idrowranges($id) {
		    incr i
		    if {$e ne {} && $e < $numcommits && $s <= $r1 && $e >= $r0
			&& ![info exists idrangedrawn($id,$i)]} {
			drawlineseg $id $i
			set idrangedrawn($id,$i) 1
		    }
		}
	    }
	}
    }
    if {$canshow > $r1} {
	set canshow $r1
    }
    while {$row < $canshow} {
	drawcmitrow $row
	incr row
    }
}

proc layoutrows {row endrow last} {
    global rowidlist rowoffsets displayorder
    global uparrowlen downarrowlen maxwidth mingaplen
    global childlist parentlist
    global idrowranges linesegends
    global commitidx
    global idinlist rowchk

    set idlist [lindex $rowidlist $row]
    set offs [lindex $rowoffsets $row]
    while {$row < $endrow} {
	set id [lindex $displayorder $row]
	set oldolds {}
	set newolds {}
	foreach p [lindex $parentlist $row] {
	    if {![info exists idinlist($p)]} {
		lappend newolds $p
	    } elseif {!$idinlist($p)} {
		lappend oldolds $p
	    }
	}
	set nev [expr {[llength $idlist] + [llength $newolds]
		       + [llength $oldolds] - $maxwidth + 1}]
	if {$nev > 0} {
	    if {!$last && $row + $uparrowlen + $mingaplen >= $commitidx} break
	    for {set x [llength $idlist]} {[incr x -1] >= 0} {} {
		set i [lindex $idlist $x]
		if {![info exists rowchk($i)] || $row >= $rowchk($i)} {
		    set r [usedinrange $i [expr {$row - $downarrowlen}] \
			       [expr {$row + $uparrowlen + $mingaplen}]]
		    if {$r == 0} {
			set idlist [lreplace $idlist $x $x]
			set offs [lreplace $offs $x $x]
			set offs [incrange $offs $x 1]
			set idinlist($i) 0
			set rm1 [expr {$row - 1}]
			lappend linesegends($rm1) $i
			lappend idrowranges($i) $rm1
			if {[incr nev -1] <= 0} break
			continue
		    }
		    set rowchk($id) [expr {$row + $r}]
		}
	    }
	    lset rowidlist $row $idlist
	    lset rowoffsets $row $offs
	}
	set col [lsearch -exact $idlist $id]
	if {$col < 0} {
	    set col [llength $idlist]
	    lappend idlist $id
	    lset rowidlist $row $idlist
	    set z {}
	    if {[lindex $childlist $row] ne {}} {
		set z [expr {[llength [lindex $rowidlist [expr {$row-1}]]] - $col}]
		unset idinlist($id)
	    }
	    lappend offs $z
	    lset rowoffsets $row $offs
	    if {$z ne {}} {
		makeuparrow $id $col $row $z
	    }
	} else {
	    unset idinlist($id)
	}
	if {[info exists idrowranges($id)]} {
	    lappend idrowranges($id) $row
	}
	incr row
	set offs [ntimes [llength $idlist] 0]
	set l [llength $newolds]
	set idlist [eval lreplace \$idlist $col $col $newolds]
	set o 0
	if {$l != 1} {
	    set offs [lrange $offs 0 [expr {$col - 1}]]
	    foreach x $newolds {
		lappend offs {}
		incr o -1
	    }
	    incr o
	    set tmp [expr {[llength $idlist] - [llength $offs]}]
	    if {$tmp > 0} {
		set offs [concat $offs [ntimes $tmp $o]]
	    }
	} else {
	    lset offs $col {}
	}
	foreach i $newolds {
	    set idinlist($i) 1
	    set idrowranges($i) $row
	}
	incr col $l
	foreach oid $oldolds {
	    set idinlist($oid) 1
	    set idlist [linsert $idlist $col $oid]
	    set offs [linsert $offs $col $o]
	    makeuparrow $oid $col $row $o
	    incr col
	}
	lappend rowidlist $idlist
	lappend rowoffsets $offs
    }
    return $row
}

proc addextraid {id row} {
    global displayorder commitrow commitinfo
    global commitidx
    global parentlist childlist children

    incr commitidx
    lappend displayorder $id
    lappend parentlist {}
    set commitrow($id) $row
    readcommit $id
    if {![info exists commitinfo($id)]} {
	set commitinfo($id) {"No commit information available"}
    }
    if {[info exists children($id)]} {
	lappend childlist $children($id)
    } else {
	lappend childlist {}
    }
}

proc layouttail {} {
    global rowidlist rowoffsets idinlist commitidx
    global idrowranges

    set row $commitidx
    set idlist [lindex $rowidlist $row]
    while {$idlist ne {}} {
	set col [expr {[llength $idlist] - 1}]
	set id [lindex $idlist $col]
	addextraid $id $row
	unset idinlist($id)
	lappend idrowranges($id) $row
	incr row
	set offs [ntimes $col 0]
	set idlist [lreplace $idlist $col $col]
	lappend rowidlist $idlist
	lappend rowoffsets $offs
    }

    foreach id [array names idinlist] {
	addextraid $id $row
	lset rowidlist $row [list $id]
	lset rowoffsets $row 0
	makeuparrow $id 0 $row 0
	lappend idrowranges($id) $row
	incr row
	lappend rowidlist {}
	lappend rowoffsets {}
    }
}

proc insert_pad {row col npad} {
    global rowidlist rowoffsets

    set pad [ntimes $npad {}]
    lset rowidlist $row [eval linsert [list [lindex $rowidlist $row]] $col $pad]
    set tmp [eval linsert [list [lindex $rowoffsets $row]] $col $pad]
    lset rowoffsets $row [incrange $tmp [expr {$col + $npad}] [expr {-$npad}]]
}

proc optimize_rows {row col endrow} {
    global rowidlist rowoffsets idrowranges linesegends displayorder

    for {} {$row < $endrow} {incr row} {
	set idlist [lindex $rowidlist $row]
	set offs [lindex $rowoffsets $row]
	set haspad 0
	for {} {$col < [llength $offs]} {incr col} {
	    if {[lindex $idlist $col] eq {}} {
		set haspad 1
		continue
	    }
	    set z [lindex $offs $col]
	    if {$z eq {}} continue
	    set isarrow 0
	    set x0 [expr {$col + $z}]
	    set y0 [expr {$row - 1}]
	    set z0 [lindex $rowoffsets $y0 $x0]
	    if {$z0 eq {}} {
		set id [lindex $idlist $col]
		if {[info exists idrowranges($id)] &&
		    $y0 > [lindex $idrowranges($id) 0]} {
		    set isarrow 1
		}
	    }
	    if {$z < -1 || ($z < 0 && $isarrow)} {
		set npad [expr {-1 - $z + $isarrow}]
		set offs [incrange $offs $col $npad]
		insert_pad $y0 $x0 $npad
		if {$y0 > 0} {
		    optimize_rows $y0 $x0 $row
		}
		set z [lindex $offs $col]
		set x0 [expr {$col + $z}]
		set z0 [lindex $rowoffsets $y0 $x0]
	    } elseif {$z > 1 || ($z > 0 && $isarrow)} {
		set npad [expr {$z - 1 + $isarrow}]
		set y1 [expr {$row + 1}]
		set offs2 [lindex $rowoffsets $y1]
		set x1 -1
		foreach z $offs2 {
		    incr x1
		    if {$z eq {} || $x1 + $z < $col} continue
		    if {$x1 + $z > $col} {
			incr npad
		    }
		    lset rowoffsets $y1 [incrange $offs2 $x1 $npad]
		    break
		}
		set pad [ntimes $npad {}]
		set idlist [eval linsert \$idlist $col $pad]
		set tmp [eval linsert \$offs $col $pad]
		incr col $npad
		set offs [incrange $tmp $col [expr {-$npad}]]
		set z [lindex $offs $col]
		set haspad 1
	    }
	    if {$z0 eq {} && !$isarrow} {
		# this line links to its first child on row $row-2
		set rm2 [expr {$row - 2}]
		set id [lindex $displayorder $rm2]
		set xc [lsearch -exact [lindex $rowidlist $rm2] $id]
		if {$xc >= 0} {
		    set z0 [expr {$xc - $x0}]
		}
	    }
	    if {$z0 ne {} && $z < 0 && $z0 > 0} {
		insert_pad $y0 $x0 1
		set offs [incrange $offs $col 1]
		optimize_rows $y0 [expr {$x0 + 1}] $row
	    }
	}
	if {!$haspad} {
	    set o {}
	    for {set col [llength $idlist]} {[incr col -1] >= 0} {} {
		set o [lindex $offs $col]
		if {$o eq {}} {
		    # check if this is the link to the first child
		    set id [lindex $idlist $col]
		    if {[info exists idrowranges($id)] &&
			$row == [lindex $idrowranges($id) 0]} {
			# it is, work out offset to child
			set y0 [expr {$row - 1}]
			set id [lindex $displayorder $y0]
			set x0 [lsearch -exact [lindex $rowidlist $y0] $id]
			if {$x0 >= 0} {
			    set o [expr {$x0 - $col}]
			}
		    }
		}
		if {$o eq {} || $o <= 0} break
	    }
	    if {$o ne {} && [incr col] < [llength $idlist]} {
		set y1 [expr {$row + 1}]
		set offs2 [lindex $rowoffsets $y1]
		set x1 -1
		foreach z $offs2 {
		    incr x1
		    if {$z eq {} || $x1 + $z < $col} continue
		    lset rowoffsets $y1 [incrange $offs2 $x1 1]
		    break
		}
		set idlist [linsert $idlist $col {}]
		set tmp [linsert $offs $col {}]
		incr col
		set offs [incrange $tmp $col -1]
	    }
	}
	lset rowidlist $row $idlist
	lset rowoffsets $row $offs
	set col 0
    }
}

proc xc {row col} {
    global canvx0 linespc
    return [expr {$canvx0 + $col * $linespc}]
}

proc yc {row} {
    global canvy0 linespc
    return [expr {$canvy0 + $row * $linespc}]
}

proc linewidth {id} {
    global thickerline lthickness

    set wid $lthickness
    if {[info exists thickerline] && $id eq $thickerline} {
	set wid [expr {2 * $lthickness}]
    }
    return $wid
}

proc drawlineseg {id i} {
    global rowoffsets rowidlist idrowranges
    global displayorder
    global canv colormap linespc

    set startrow [lindex $idrowranges($id) [expr {2 * $i}]]
    set row [lindex $idrowranges($id) [expr {2 * $i + 1}]]
    if {$startrow == $row} return
    assigncolor $id
    set coords {}
    set col [lsearch -exact [lindex $rowidlist $row] $id]
    if {$col < 0} {
	puts "oops: drawline: id $id not on row $row"
	return
    }
    set lasto {}
    set ns 0
    while {1} {
	set o [lindex $rowoffsets $row $col]
	if {$o eq {}} break
	if {$o ne $lasto} {
	    # changing direction
	    set x [xc $row $col]
	    set y [yc $row]
	    lappend coords $x $y
	    set lasto $o
	}
	incr col $o
	incr row -1
    }
    set x [xc $row $col]
    set y [yc $row]
    lappend coords $x $y
    if {$i == 0} {
	# draw the link to the first child as part of this line
	incr row -1
	set child [lindex $displayorder $row]
	set ccol [lsearch -exact [lindex $rowidlist $row] $child]
	if {$ccol >= 0} {
	    set x [xc $row $ccol]
	    set y [yc $row]
	    if {$ccol < $col - 1} {
		lappend coords [xc $row [expr {$col - 1}]] [yc $row]
	    } elseif {$ccol > $col + 1} {
		lappend coords [xc $row [expr {$col + 1}]] [yc $row]
	    }
	    lappend coords $x $y
	}
    }
    if {[llength $coords] < 4} return
    set last [expr {[llength $idrowranges($id)] / 2 - 1}]
    if {$i < $last} {
	# This line has an arrow at the lower end: check if the arrow is
	# on a diagonal segment, and if so, work around the Tk 8.4
	# refusal to draw arrows on diagonal lines.
	set x0 [lindex $coords 0]
	set x1 [lindex $coords 2]
	if {$x0 != $x1} {
	    set y0 [lindex $coords 1]
	    set y1 [lindex $coords 3]
	    if {$y0 - $y1 <= 2 * $linespc && $x1 == [lindex $coords 4]} {
		# we have a nearby vertical segment, just trim off the diag bit
		set coords [lrange $coords 2 end]
	    } else {
		set slope [expr {($x0 - $x1) / ($y0 - $y1)}]
		set xi [expr {$x0 - $slope * $linespc / 2}]
		set yi [expr {$y0 - $linespc / 2}]
		set coords [lreplace $coords 0 1 $xi $y0 $xi $yi]
	    }
	}
    }
    set arrow [expr {2 * ($i > 0) + ($i < $last)}]
    set arrow [lindex {none first last both} $arrow]
    set t [$canv create line $coords -width [linewidth $id] \
	       -fill $colormap($id) -tags lines.$id -arrow $arrow]
    $canv lower $t
    bindline $t $id
}

proc drawparentlinks {id row col olds} {
    global rowidlist canv colormap idrowranges

    set row2 [expr {$row + 1}]
    set x [xc $row $col]
    set y [yc $row]
    set y2 [yc $row2]
    set ids [lindex $rowidlist $row2]
    # rmx = right-most X coord used
    set rmx 0
    foreach p $olds {
	set i [lsearch -exact $ids $p]
	if {$i < 0} {
	    puts "oops, parent $p of $id not in list"
	    continue
	}
	set x2 [xc $row2 $i]
	if {$x2 > $rmx} {
	    set rmx $x2
	}
	if {[info exists idrowranges($p)] &&
	    $row2 == [lindex $idrowranges($p) 0] &&
	    $row2 < [lindex $idrowranges($p) 1]} {
	    # drawlineseg will do this one for us
	    continue
	}
	assigncolor $p
	# should handle duplicated parents here...
	set coords [list $x $y]
	if {$i < $col - 1} {
	    lappend coords [xc $row [expr {$i + 1}]] $y
	} elseif {$i > $col + 1} {
	    lappend coords [xc $row [expr {$i - 1}]] $y
	}
	lappend coords $x2 $y2
	set t [$canv create line $coords -width [linewidth $p] \
		   -fill $colormap($p) -tags lines.$p]
	$canv lower $t
	bindline $t $p
    }
    return $rmx
}

proc drawlines {id} {
    global colormap canv
    global idrowranges idrangedrawn
    global childlist iddrawn commitrow rowidlist

    $canv delete lines.$id
    set nr [expr {[llength $idrowranges($id)] / 2}]
    for {set i 0} {$i < $nr} {incr i} {
	if {[info exists idrangedrawn($id,$i)]} {
	    drawlineseg $id $i
	}
    }
    foreach child [lindex $childlist $commitrow($id)] {
	if {[info exists iddrawn($child)]} {
	    set row $commitrow($child)
	    set col [lsearch -exact [lindex $rowidlist $row] $child]
	    if {$col >= 0} {
		drawparentlinks $child $row $col [list $id]
	    }
	}
    }
}

proc drawcmittext {id row col rmx} {
    global linespc canv canv2 canv3 canvy0
    global commitlisted commitinfo rowidlist
    global rowtextx idpos idtags idheads idotherrefs
    global linehtag linentag linedtag
    global mainfont namefont canvxmax

    set ofill [expr {[lindex $commitlisted $row]? "blue": "white"}]
    set x [xc $row $col]
    set y [yc $row]
    set orad [expr {$linespc / 3}]
    set t [$canv create oval [expr {$x - $orad}] [expr {$y - $orad}] \
	       [expr {$x + $orad - 1}] [expr {$y + $orad - 1}] \
	       -fill $ofill -outline black -width 1]
    $canv raise $t
    $canv bind $t <1> {selcanvline {} %x %y}
    set xt [xc $row [llength [lindex $rowidlist $row]]]
    if {$xt < $rmx} {
	set xt $rmx
    }
    set rowtextx($row) $xt
    set idpos($id) [list $x $xt $y]
    if {[info exists idtags($id)] || [info exists idheads($id)]
	|| [info exists idotherrefs($id)]} {
	set xt [drawtags $id $x $xt $y]
    }
    set headline [lindex $commitinfo($id) 0]
    set name [lindex $commitinfo($id) 1]
    set date [lindex $commitinfo($id) 2]
    set date [formatdate $date]
    set linehtag($row) [$canv create text $xt $y -anchor w \
			    -text $headline -font $mainfont ]
    $canv bind $linehtag($row) <Button-3> "rowmenu %X %Y $id"
    set linentag($row) [$canv2 create text 3 $y -anchor w \
			    -text $name -font $namefont]
    set linedtag($row) [$canv3 create text 3 $y -anchor w \
			    -text $date -font $mainfont]
    set xr [expr {$xt + [font measure $mainfont $headline]}]
    if {$xr > $canvxmax} {
	set canvxmax $xr
	setcanvscroll
    }
}

proc drawcmitrow {row} {
    global displayorder rowidlist
    global idrowranges idrangedrawn iddrawn
    global commitinfo commitlisted parentlist numcommits

    if {$row >= $numcommits} return
    foreach id [lindex $rowidlist $row] {
	if {![info exists idrowranges($id)]} continue
	set i -1
	foreach {s e} $idrowranges($id) {
	    incr i
	    if {$row < $s} continue
	    if {$e eq {}} break
	    if {$row <= $e} {
		if {$e < $numcommits && ![info exists idrangedrawn($id,$i)]} {
		    drawlineseg $id $i
		    set idrangedrawn($id,$i) 1
		}
		break
	    }
	}
    }

    set id [lindex $displayorder $row]
    if {[info exists iddrawn($id)]} return
    set col [lsearch -exact [lindex $rowidlist $row] $id]
    if {$col < 0} {
	puts "oops, row $row id $id not in list"
	return
    }
    if {![info exists commitinfo($id)]} {
	getcommit $id
    }
    assigncolor $id
    set olds [lindex $parentlist $row]
    if {$olds ne {}} {
	set rmx [drawparentlinks $id $row $col $olds]
    } else {
	set rmx 0
    }
    drawcmittext $id $row $col $rmx
    set iddrawn($id) 1
}

proc drawfrac {f0 f1} {
    global numcommits canv
    global linespc

    set ymax [lindex [$canv cget -scrollregion] 3]
    if {$ymax eq {} || $ymax == 0} return
    set y0 [expr {int($f0 * $ymax)}]
    set row [expr {int(($y0 - 3) / $linespc) - 1}]
    if {$row < 0} {
	set row 0
    }
    set y1 [expr {int($f1 * $ymax)}]
    set endrow [expr {int(($y1 - 3) / $linespc) + 1}]
    if {$endrow >= $numcommits} {
	set endrow [expr {$numcommits - 1}]
    }
    for {} {$row <= $endrow} {incr row} {
	drawcmitrow $row
    }
}

proc drawvisible {} {
    global canv
    eval drawfrac [$canv yview]
}

proc clear_display {} {
    global iddrawn idrangedrawn

    allcanvs delete all
    catch {unset iddrawn}
    catch {unset idrangedrawn}
}

proc assigncolor {id} {
    global colormap colors nextcolor
    global commitrow parentlist children childlist
    global cornercrossings crossings

    if {[info exists colormap($id)]} return
    set ncolors [llength $colors]
    if {[info exists commitrow($id)]} {
	set kids [lindex $childlist $commitrow($id)]
    } elseif {[info exists children($id)]} {
	set kids $children($id)
    } else {
	set kids {}
    }
    if {[llength $kids] == 1} {
	set child [lindex $kids 0]
	if {[info exists colormap($child)]
	    && [llength [lindex $parentlist $commitrow($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 $kids {
	    if {[info exists colormap($child)]
		&& [lsearch -exact $badcolors $colormap($child)] < 0} {
		lappend badcolors $colormap($child)
	    }
	    foreach p [lindex $parentlist $commitrow($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 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 1"
}

proc drawtags {id x xt y1} {
    global idtags idheads idotherrefs
    global linespc lthickness
    global canv mainfont commitrow rowtextx

    set marks {}
    set ntags 0
    set nheads 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)]
	set nheads [llength $idheads($id)]
    }
    if {[info exists idotherrefs($id)]} {
	set marks [concat $marks $idotherrefs($id)]
    }
    if {$marks eq {}} {
	return $xt
    }

    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 $lthickness -fill black -tags tag.$id]
    $canv lower $t
    foreach tag $marks x $xvals wid $wvals {
	set xl [expr {$x + $delta}]
	set xr [expr {$x + $delta + $wid + $lthickness}]
	if {[incr ntags -1] >= 0} {
	    # draw a tag
	    set t [$canv create polygon $x [expr {$yt + $delta}] $xl $yt \
		       $xr $yt $xr $yb $xl $yb $x [expr {$yb - $delta}] \
		       -width 1 -outline black -fill yellow -tags tag.$id]
	    $canv bind $t <1> [list showtag $tag 1]
	    set rowtextx($commitrow($id)) [expr {$xr + $linespc}]
	} else {
	    # draw a head or other ref
	    if {[incr nheads -1] >= 0} {
		set col green
	    } else {
		set col "#ddddff"
	    }
	    set xl [expr {$xl - $delta/2}]
	    $canv create polygon $x $yt $xr $yt $xr $yb $x $yb \
		-width 1 -outline black -fill $col -tags tag.$id
	}
	set t [$canv create text $xl $y1 -anchor w -text $tag \
		   -font $mainfont -tags tag.$id]
	if {$ntags >= 0} {
	    $canv bind $t <1> [list showtag $tag 1]
	}
    }
    return $xt
}

proc checkcrossings {row endrow} {
    global displayorder parentlist rowidlist

    for {} {$row < $endrow} {incr row} {
	set id [lindex $displayorder $row]
	set i [lsearch -exact [lindex $rowidlist $row] $id]
	if {$i < 0} continue
	set idlist [lindex $rowidlist [expr {$row+1}]]
	foreach p [lindex $parentlist $row] {
	    set j [lsearch -exact $idlist $p]
	    if {$j > 0} {
		if {$j < $i - 1} {
		    notecrossings $row $p $j $i [expr {$j+1}]
		} elseif {$j > $i + 1} {
		    notecrossings $row $p $i $j [expr {$j-1}]
		}
	    }
	}
    }
}

proc notecrossings {row id lo hi corner} {
    global rowidlist crossings cornercrossings

    for {set i $lo} {[incr i] < $hi} {} {
	set p [lindex [lindex $rowidlist $row] $i]
	if {$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 xcoord {i level ln} {
    global canvx0 xspc1 xspc2

    set x [expr {$canvx0 + $i * $xspc1($ln)}]
    if {$i > 0 && $i == $level} {
	set x [expr {$x + 0.5 * ($xspc2 - $xspc1($ln))}]
    } elseif {$i > $level} {
	set x [expr {$x + $xspc2 - $xspc1($ln)}]
    }
    return $x
}

proc finishcommits {} {
    global commitidx phase
    global canv mainfont ctext maincursor textcursor
    global findinprogress

    if {$commitidx > 0} {
	drawrest
    } else {
	$canv delete all
	$canv create text 3 3 -anchor nw -text "No commits selected" \
	    -font $mainfont -tags textitems
    }
    if {![info exists findinprogress]} {
	. config -cursor $maincursor
	settextcursor $textcursor
    }
    set phase {}
}

# Don't change the text pane cursor if it is currently the hand cursor,
# showing that we are over a sha1 ID link.
proc settextcursor {c} {
    global ctext curtextcursor

    if {[$ctext cget -cursor] == $curtextcursor} {
	$ctext config -cursor $c
    }
    set curtextcursor $c
}

proc drawrest {} {
    global numcommits
    global startmsecs
    global canvy0 numcommits linespc
    global rowlaidout commitidx

    set row $rowlaidout
    layoutrows $rowlaidout $commitidx 1
    layouttail
    optimize_rows $row 0 $commitidx
    showstuff $commitidx

    set drawmsecs [expr {[clock clicks -milliseconds] - $startmsecs}]
    #puts "overall $drawmsecs ms for $numcommits commits"
}

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 displayorder linehtag linentag linedtag
    global mainfont namefont canv canv2 canv3 selectedline
    global matchinglines foundstring foundstrlen matchstring
    global commitdata

    stopfindproc
    unmarkmatches
    focus .
    set matchinglines {}
    if {$findloc == "Pickaxe"} {
	findpatches
	return
    }
    if {$findtype == "IgnCase"} {
	set foundstring [string tolower $findstring]
    } else {
	set foundstring $findstring
    }
    set foundstrlen [string length $findstring]
    if {$foundstrlen == 0} return
    regsub -all {[*?\[\\]} $foundstring {\\&} matchstring
    set matchstring "*$matchstring*"
    if {$findloc == "Files"} {
	findfiles
	return
    }
    if {![info exists selectedline]} {
	set oldsel -1
    } else {
	set oldsel $selectedline
    }
    set didsel 0
    set fldtypes {Headline Author Date Committer CDate Comment}
    set l -1
    foreach id $displayorder {
	set d $commitdata($id)
	incr l
	if {$findtype == "Regexp"} {
	    set doesmatch [regexp $foundstring $d]
	} elseif {$findtype == "IgnCase"} {
	    set doesmatch [string match -nocase $matchstring $d]
	} else {
	    set doesmatch [string match $matchstring $d]
	}
	if {!$doesmatch} continue
	if {![info exists commitinfo($id)]} {
	    getcommit $id
	}
	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"} {
		drawcmitrow $l
		markmatches $canv $l $f $linehtag($l) $matches $mainfont
	    } elseif {$ty == "Author"} {
		drawcmitrow $l
		markmatches $canv2 $l $f $linentag($l) $matches $namefont
	    } elseif {$ty == "Date"} {
		drawcmitrow $l
		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 $l 1
    if {$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 {restart} {
    global matchinglines selectedline
    if {![info exists matchinglines]} {
	if {$restart} {
	    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 findlocchange {name ix op} {
    global findloc findtype findtypemenu
    if {$findloc == "Pickaxe"} {
	set findtype Exact
	set state disabled
    } else {
	set state normal
    }
    $findtypemenu entryconf 1 -state $state
    $findtypemenu entryconf 2 -state $state
}

proc stopfindproc {{done 0}} {
    global findprocpid findprocfile findids
    global ctext findoldcursor phase maincursor textcursor
    global findinprogress

    catch {unset findids}
    if {[info exists findprocpid]} {
	if {!$done} {
	    catch {exec kill $findprocpid}
	}
	catch {close $findprocfile}
	unset findprocpid
    }
    if {[info exists findinprogress]} {
	unset findinprogress
	if {$phase != "incrdraw"} {
	    . config -cursor $maincursor
	    settextcursor $textcursor
	}
    }
}

proc findpatches {} {
    global findstring selectedline numcommits
    global findprocpid findprocfile
    global finddidsel ctext displayorder findinprogress
    global findinsertpos

    if {$numcommits == 0} return

    # make a list of all the ids to search, starting at the one
    # after the selected line (if any)
    if {[info exists selectedline]} {
	set l $selectedline
    } else {
	set l -1
    }
    set inputids {}
    for {set i 0} {$i < $numcommits} {incr i} {
	if {[incr l] >= $numcommits} {
	    set l 0
	}
	append inputids [lindex $displayorder $l] "\n"
    }

    if {[catch {
	set f [open [list | git-diff-tree --stdin -s -r -S$findstring \
			 << $inputids] r]
    } err]} {
	error_popup "Error starting search process: $err"
	return
    }

    set findinsertpos end
    set findprocfile $f
    set findprocpid [pid $f]
    fconfigure $f -blocking 0
    fileevent $f readable readfindproc
    set finddidsel 0
    . config -cursor watch
    settextcursor watch
    set findinprogress 1
}

proc readfindproc {} {
    global findprocfile finddidsel
    global commitrow matchinglines findinsertpos

    set n [gets $findprocfile line]
    if {$n < 0} {
	if {[eof $findprocfile]} {
	    stopfindproc 1
	    if {!$finddidsel} {
		bell
	    }
	}
	return
    }
    if {![regexp {^[0-9a-f]{40}} $line id]} {
	error_popup "Can't parse git-diff-tree output: $line"
	stopfindproc
	return
    }
    if {![info exists commitrow($id)]} {
	puts stderr "spurious id: $id"
	return
    }
    set l $commitrow($id)
    insertmatch $l $id
}

proc insertmatch {l id} {
    global matchinglines findinsertpos finddidsel

    if {$findinsertpos == "end"} {
	if {$matchinglines != {} && $l < [lindex $matchinglines 0]} {
	    set matchinglines [linsert $matchinglines 0 $l]
	    set findinsertpos 1
	} else {
	    lappend matchinglines $l
	}
    } else {
	set matchinglines [linsert $matchinglines $findinsertpos $l]
	incr findinsertpos
    }
    markheadline $l $id
    if {!$finddidsel} {
	findselectline $l
	set finddidsel 1
    }
}

proc findfiles {} {
    global selectedline numcommits displayorder ctext
    global ffileline finddidsel parentlist
    global findinprogress findstartline findinsertpos
    global treediffs fdiffid fdiffsneeded fdiffpos
    global findmergefiles

    if {$numcommits == 0} return

    if {[info exists selectedline]} {
	set l [expr {$selectedline + 1}]
    } else {
	set l 0
    }
    set ffileline $l
    set findstartline $l
    set diffsneeded {}
    set fdiffsneeded {}
    while 1 {
	set id [lindex $displayorder $l]
	if {$findmergefiles || [llength [lindex $parentlist $l]] == 1} {
	    if {![info exists treediffs($id)]} {
		append diffsneeded "$id\n"
		lappend fdiffsneeded $id
	    }
	}
	if {[incr l] >= $numcommits} {
	    set l 0
	}
	if {$l == $findstartline} break
    }

    # start off a git-diff-tree process if needed
    if {$diffsneeded ne {}} {
	if {[catch {
	    set df [open [list | git-diff-tree -r --stdin << $diffsneeded] r]
	} err ]} {
	    error_popup "Error starting search process: $err"
	    return
	}
	catch {unset fdiffid}
	set fdiffpos 0
	fconfigure $df -blocking 0
	fileevent $df readable [list readfilediffs $df]
    }

    set finddidsel 0
    set findinsertpos end
    set id [lindex $displayorder $l]
    . config -cursor watch
    settextcursor watch
    set findinprogress 1
    findcont
    update
}

proc readfilediffs {df} {
    global findid fdiffid fdiffs

    set n [gets $df line]
    if {$n < 0} {
	if {[eof $df]} {
	    donefilediff
	    if {[catch {close $df} err]} {
		stopfindproc
		bell
		error_popup "Error in git-diff-tree: $err"
	    } elseif {[info exists findid]} {
		set id $findid
		stopfindproc
		bell
		error_popup "Couldn't find diffs for $id"
	    }
	}
	return
    }
    if {[regexp {^([0-9a-f]{40})$} $line match id]} {
	# start of a new string of diffs
	donefilediff
	set fdiffid $id
	set fdiffs {}
    } elseif {[string match ":*" $line]} {
	lappend fdiffs [lindex $line 5]
    }
}

proc donefilediff {} {
    global fdiffid fdiffs treediffs findid
    global fdiffsneeded fdiffpos

    if {[info exists fdiffid]} {
	while {[lindex $fdiffsneeded $fdiffpos] ne $fdiffid
	       && $fdiffpos < [llength $fdiffsneeded]} {
	    # git-diff-tree doesn't output anything for a commit
	    # which doesn't change anything
	    set nullid [lindex $fdiffsneeded $fdiffpos]
	    set treediffs($nullid) {}
	    if {[info exists findid] && $nullid eq $findid} {
		unset findid
		findcont
	    }
	    incr fdiffpos
	}
	incr fdiffpos

	if {![info exists treediffs($fdiffid)]} {
	    set treediffs($fdiffid) $fdiffs
	}
	if {[info exists findid] && $fdiffid eq $findid} {
	    unset findid
	    findcont
	}
    }
}

proc findcont {} {
    global findid treediffs parentlist
    global ffileline findstartline finddidsel
    global displayorder numcommits matchinglines findinprogress
    global findmergefiles

    set l $ffileline
    while {1} {
	set id [lindex $displayorder $l]
	if {$findmergefiles || [llength [lindex $parentlist $l]] == 1} {
	    if {![info exists treediffs($id)]} {
		set findid $id
		set ffileline $l
		return
	    }
	    set doesmatch 0
	    foreach f $treediffs($id) {
		set x [findmatches $f]
		if {$x != {}} {
		    set doesmatch 1
		    break
		}
	    }
	    if {$doesmatch} {
		insertmatch $l $id
	    }
	}
	if {[incr l] >= $numcommits} {
	    set l 0
	}
	if {$l == $findstartline} break
    }
    stopfindproc
    if {!$finddidsel} {
	bell
    }
}

# mark a commit as matching by putting a yellow background
# behind the headline
proc markheadline {l id} {
    global canv mainfont linehtag

    drawcmitrow $l
    set bbox [$canv bbox $linehtag($l)]
    set t [$canv create rect $bbox -outline {} -tags matches -fill yellow]
    $canv lower $t
}

# mark the bits of a headline, author or date that match a find string
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 findids
    allcanvs delete matches
    catch {unset matchinglines}
    catch {unset findids}
}

proc selcanvline {w x y} {
    global canv canvy0 ctext linespc
    global 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 1
}

proc commit_descriptor {p} {
    global commitinfo
    set l "..."
    if {[info exists commitinfo($p)]} {
	set l [lindex $commitinfo($p) 0]
    }
    return "$p ($l)"
}

# append some text to the ctext widget, and make any SHA1 ID
# that we know about be a clickable link.
proc appendwithlinks {text} {
    global ctext commitrow linknum

    set start [$ctext index "end - 1c"]
    $ctext insert end $text
    $ctext insert end "\n"
    set links [regexp -indices -all -inline {[0-9a-f]{40}} $text]
    foreach l $links {
	set s [lindex $l 0]
	set e [lindex $l 1]
	set linkid [string range $text $s $e]
	if {![info exists commitrow($linkid)]} continue
	incr e
	$ctext tag add link "$start + $s c" "$start + $e c"
	$ctext tag add link$linknum "$start + $s c" "$start + $e c"
	$ctext tag bind link$linknum <1> [list selectline $commitrow($linkid) 1]
	incr linknum
    }
    $ctext tag conf link -foreground blue -underline 1
    $ctext tag bind link <Enter> { %W configure -cursor hand2 }
    $ctext tag bind link <Leave> { %W configure -cursor $curtextcursor }
}

proc viewnextline {dir} {
    global canv linespc

    $canv delete hover
    set ymax [lindex [$canv cget -scrollregion] 3]
    set wnow [$canv yview]
    set wtop [expr {[lindex $wnow 0] * $ymax}]
    set newtop [expr {$wtop + $dir * $linespc}]
    if {$newtop < 0} {
	set newtop 0
    } elseif {$newtop > $ymax} {
	set newtop $ymax
    }
    allcanvs yview moveto [expr {$newtop * 1.0 / $ymax}]
}

proc selectline {l isnew} {
    global canv canv2 canv3 ctext commitinfo selectedline
    global displayorder linehtag linentag linedtag
    global canvy0 linespc parentlist childlist
    global cflist currentid sha1entry
    global commentend idtags linknum
    global mergemax numcommits

    $canv delete hover
    normalline
    if {$l < 0 || $l >= $numcommits} return
    set y [expr {$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} {
	    se