git-gui: Allow specifying an initial line for git gui blame.

Add a command-line option to make git gui blame automatically
scroll to a specific line in the file. Useful for integration
with other tools.
Signed-off-by: NAlexander Gavrilov <angavrilov@gmail.com>
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

git-gui.sh

@@ -2296,10 +2296,15 @@ proc usage {} {
 switch -- $subcommand {
 browser -
 blame {
-	set subcommand_args {rev? path}
+	if {$subcommand eq "blame"} {
+		set subcommand_args {[--line=<num>] rev? path}
+	} else {
+		set subcommand_args {rev? path}
+	}
 	if {$argv eq {}} usage
 	set head {}
 	set path {}
+	set jump_spec {}
 	set is_path 0
 	foreach a $argv {
 		if {$is_path || [file exists $_prefix$a]} {
@@ -2313,6 +2318,9 @@ blame {
 				set path {}
 			}
 			set is_path 1
+		} elseif {[regexp {^--line=(\d+)$} $a a lnum]} {
+			if {$jump_spec ne {} || $head ne {}} usage
+			set jump_spec [list $lnum]
 		} elseif {$head eq {}} {
 			if {$head ne {}} usage
 			set head $a
@@ -2344,6 +2352,7 @@ blame {
 
 	switch -- $subcommand {
 	browser {
+		if {$jump_spec ne {}} usage
 		if {$head eq {}} {
 			if {$path ne {} && [file isdirectory $path]} {
 				set head $current_branch
@@ -2359,7 +2368,7 @@ blame {
 			puts stderr [mc "fatal: cannot stat path %s: No such file or directory" $path]
 			exit 1
 		}
-		blame::new $head $path
+		blame::new $head $path $jump_spec
 	}
 	}
 	return

lib/blame.tcl

@@ -58,7 +58,7 @@ field tooltip_t         {} ; # Text widget in $tooltip_wm
 field tooltip_timer     {} ; # Current timer event for our tooltip
 field tooltip_commit    {} ; # Commit(s) in tooltip
 
-constructor new {i_commit i_path} {
+constructor new {i_commit i_path i_jump} {
 	global cursor_ptr
 	variable active_color
 	variable group_colors
@@ -338,7 +338,7 @@ constructor new {i_commit i_path} {
 	wm protocol $top WM_DELETE_WINDOW "destroy $top"
 	bind $top <Destroy> [cb _kill]
 
-	_load $this {}
+	_load $this $i_jump
 }
 
 method _kill {} {

lib/browser.tcl

@@ -151,7 +151,7 @@ method _enter {} {
 				append p [lindex $n 1]
 			}
 			append p $name
-			blame::new $browser_commit $p
+			blame::new $browser_commit $p {}
 		}
 		}
 	}