git-gui: Support the encoding menu in gui blame.

Allow dynamically changing the encoding from the blame
viewer as well.

Signed-off-by: Alexander Gavrilov <angavrilov@gmail.com>
Tested-by: Johannes Sixt <johannes.sixt@telecom.at>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

lib/blame.tcl

@@ -256,9 +256,16 @@ constructor new {i_commit i_path i_jump} {
 	$w.ctxm add command \
 		-label [mc "Copy Commit"] \
 		-command [cb _copycommit]
+	$w.ctxm add separator
+	menu $w.ctxm.enc
+	build_encoding_menu $w.ctxm.enc [cb _setencoding]
+	$w.ctxm add cascade \
+		-label [mc "Encoding"] \
+		-menu $w.ctxm.enc
 	$w.ctxm add command \
 		-label [mc "Do Full Copy Detection"] \
 		-command [cb _fullcopyblame]
+	$w.ctxm add separator
 	$w.ctxm add command \
 		-label [mc "Show History Context"] \
 		-command [cb _gitkcommit]
@@ -791,6 +798,16 @@ method _click {cur_w pos} {
 	_showcommit $this $cur_w $lno
 }
 
+method _setencoding {enc} {
+	force_path_encoding $path $enc
+	_load $this [list \
+		$highlight_column \
+		$highlight_line \
+		[lindex [$w_file xview] 0] \
+		[lindex [$w_file yview] 0] \
+		]
+}
+
 method _load_commit {cur_w cur_d pos} {
 	upvar #0 $cur_d line_data
 	set lno [lindex [split [$cur_w index $pos] .] 0]