+# With path limiting, we mightn't get the actual HEAD commit,
+# so ask git rev-list what is the first ancestor of HEAD that
+# touches a file in the path limit.
+proc get_viewmainhead {view} {
+ global viewmainheadid vfilelimit viewinstances mainheadid
+
+ catch {
+ set rfd [open [concat | git rev-list -1 $mainheadid \
+ -- $vfilelimit($view)] r]
+ set j [reg_instance $rfd]
+ lappend viewinstances($view) $j
+ fconfigure $rfd -blocking 0
+ filerun $rfd [list getviewhead $rfd $j $view]
+ set viewmainheadid($curview) {}
+ }
+}
+
+# git rev-list should give us just 1 line to use as viewmainheadid($view)
+proc getviewhead {fd inst view} {
+ global viewmainheadid commfd curview viewinstances showlocalchanges
+
+ set id {}
+ if {[gets $fd line] < 0} {
+ if {![eof $fd]} {
+ return 1
+ }
+ } elseif {[string length $line] == 40 && [string is xdigit $line]} {
+ set id $line
+ }
+ set viewmainheadid($view) $id
+ close $fd
+ unset commfd($inst)
+ set i [lsearch -exact $viewinstances($view) $inst]
+ if {$i >= 0} {
+ set viewinstances($view) [lreplace $viewinstances($view) $i $i]
+ }
+ if {$showlocalchanges && $id ne {} && $view == $curview} {
+ doshowlocalchanges
+ }
+ return 0
+}
+