X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=git-gui%2Flib%2Fdiff.tcl;h=1970b601e1ce34af120cfc3ee16e1b2c26c6b19d;hb=d11ddaff021be8006e71b43a5205c48f2dac7f18;hp=96ba94906cf8037b58c2ba135654da840f9fff9a;hpb=86d72443215612f66f77dfc57ec9613c8153617c;p=git.git

diff --git a/git-gui/lib/diff.tcl b/git-gui/lib/diff.tcl
index 96ba94906..1970b601e 100644
--- a/git-gui/lib/diff.tcl
+++ b/git-gui/lib/diff.tcl
@@ -19,6 +19,7 @@ proc clear_diff {} {
 proc reshow_diff {} {
 	global file_states file_lists
 	global current_diff_path current_diff_side
+	global ui_diff
 
 	set p $current_diff_path
 	if {$p eq {}} {
@@ -28,7 +29,8 @@ proc reshow_diff {} {
 		|| [lsearch -sorted -exact $file_lists($current_diff_side) $p] == -1} {
 		clear_diff
 	} else {
-		show_diff $p $current_diff_side
+		set save_pos [lindex [$ui_diff yview] 0]
+		show_diff $p $current_diff_side {} $save_pos
 	}
 }
 
@@ -52,7 +54,7 @@ A rescan will be automatically started to find other files which may have the sa
 	rescan ui_ready 0
 }
 
-proc show_diff {path w {lno {}}} {
+proc show_diff {path w {lno {}} {scroll_pos {}}} {
 	global file_states file_lists
 	global is_3way_diff diff_active repo_config
 	global ui_diff ui_index ui_workdir
@@ -151,6 +153,10 @@ proc show_diff {path w {lno {}}} {
 		$ui_diff conf -state disabled
 		set diff_active 0
 		unlock_index
+		if {$scroll_pos ne {}} {
+			update
+			$ui_diff yview moveto $scroll_pos
+		}
 		ui_ready
 		return
 	}
@@ -169,7 +175,7 @@ proc show_diff {path w {lno {}}} {
 
 	lappend cmd -p
 	lappend cmd --no-color
-	if {$repo_config(gui.diffcontext) >= 0} {
+	if {$repo_config(gui.diffcontext) >= 1} {
 		lappend cmd "-U$repo_config(gui.diffcontext)"
 	}
 	if {$w eq $ui_index} {
@@ -186,14 +192,15 @@ proc show_diff {path w {lno {}}} {
 		return
 	}
 
+	set ::current_diff_inheader 1
 	fconfigure $fd \
 		-blocking 0 \
 		-encoding binary \
 		-translation binary
-	fileevent $fd readable [list read_diff $fd]
+	fileevent $fd readable [list read_diff $fd $scroll_pos]
 }
 
-proc read_diff {fd} {
+proc read_diff {fd scroll_pos} {
 	global ui_diff diff_active
 	global is_3way_diff current_diff_header
 
@@ -201,18 +208,21 @@ proc read_diff {fd} {
 	while {[gets $fd line] >= 0} {
 		# -- Cleanup uninteresting diff header lines.
 		#
-		if {   [string match {diff --git *}      $line]
-			|| [string match {diff --cc *}       $line]
-			|| [string match {diff --combined *} $line]
-			|| [string match {--- *}             $line]
-			|| [string match {+++ *}             $line]} {
-			append current_diff_header $line "\n"
-			continue
+		if {$::current_diff_inheader} {
+			if {   [string match {diff --git *}      $line]
+			    || [string match {diff --cc *}       $line]
+			    || [string match {diff --combined *} $line]
+			    || [string match {--- *}             $line]
+			    || [string match {+++ *}             $line]} {
+				append current_diff_header $line "\n"
+				continue
+			}
 		}
 		if {[string match {index *} $line]} continue
 		if {$line eq {deleted file mode 120000}} {
 			set line "deleted symlink"
 		}
+		set ::current_diff_inheader 0
 
 		# -- Automatically detect if this is a 3 way diff.
 		#
@@ -282,6 +292,10 @@ proc read_diff {fd} {
 		close $fd
 		set diff_active 0
 		unlock_index
+		if {$scroll_pos ne {}} {
+			update
+			$ui_diff yview moveto $scroll_pos
+		}
 		ui_ready
 
 		if {[$ui_diff index end] eq {2.0}} {
@@ -411,6 +425,53 @@ proc apply_line {x y} {
 	set hh [lindex [split $hh ,] 0]
 	set hln [lindex [split $hh -] 1]
 
+	# There is a special situation to take care of. Consider this hunk:
+	#
+	#    @@ -10,4 +10,4 @@
+	#     context before
+	#    -old 1
+	#    -old 2
+	#    +new 1
+	#    +new 2
+	#     context after
+	#
+	# We used to keep the context lines in the order they appear in the
+	# hunk. But then it is not possible to correctly stage only
+	# "-old 1" and "+new 1" - it would result in this staged text:
+	#
+	#    context before
+	#    old 2
+	#    new 1
+	#    context after
+	#
+	# (By symmetry it is not possible to *un*stage "old 2" and "new 2".)
+	#
+	# We resolve the problem by introducing an asymmetry, namely, when
+	# a "+" line is *staged*, it is moved in front of the context lines
+	# that are generated from the "-" lines that are immediately before
+	# the "+" block. That is, we construct this patch:
+	#
+	#    @@ -10,4 +10,5 @@
+	#     context before
+	#    +new 1
+	#     old 1
+	#     old 2
+	#     context after
+	#
+	# But we do *not* treat "-" lines that are *un*staged in a special
+	# way.
+	#
+	# With this asymmetry it is possible to stage the change
+	# "old 1" -> "new 1" directly, and to stage the change
+	# "old 2" -> "new 2" by first staging the entire hunk and
+	# then unstaging the change "old 1" -> "new 1".
+
+	# This is non-empty if and only if we are _staging_ changes;
+	# then it accumulates the consecutive "-" lines (after converting
+	# them to context lines) in order to be moved after the "+" change
+	# line.
+	set pre_context {}
+
 	set n 0
 	set i_l [$ui_diff index "$i_l + 1 lines"]
 	set patch {}
@@ -422,16 +483,27 @@ proc apply_line {x y} {
 		    [$ui_diff compare $the_l < $next_l]} {
 			# the line to stage/unstage
 			set ln [$ui_diff get $i_l $next_l]
-			set patch "$patch$ln"
+			if {$c1 eq {-}} {
+				set n [expr $n+1]
+				set patch "$patch$pre_context$ln"
+			} else {
+				set patch "$patch$ln$pre_context"
+			}
+			set pre_context {}
 		} elseif {$c1 ne {-} && $c1 ne {+}} {
 			# context line
 			set ln [$ui_diff get $i_l $next_l]
-			set patch "$patch$ln"
+			set patch "$patch$pre_context$ln"
 			set n [expr $n+1]
+			set pre_context {}
 		} elseif {$c1 eq $to_context} {
 			# turn change line into context line
 			set ln [$ui_diff get "$i_l + 1 chars" $next_l]
-			set patch "$patch $ln"
+			if {$c1 eq {-}} {
+				set pre_context "$pre_context $ln"
+			} else {
+				set patch "$patch $ln"
+			}
 			set n [expr $n+1]
 		}
 		set i_l $next_l