git-commit-vandalism/lib/diff.tcl
Alexander Gavrilov 584fa9ccf4 git-gui: Avoid an infinite rescan loop in handle_empty_diff.
If the index update machinery and git diff happen to disagree
on whether a particular file is modified, it may cause git-gui
to enter an infinite index rescan loop, where an empty diff
starts a rescan, which finds the same set of files modified,
and tries to display the diff for the first one, which happens
to be the empty one. A current example of a possible disagreement
point is the autocrlf filter.

This patch breaks the loop by using a global counter to track
the auto-rescans. The variable is reset whenever a non-empty
diff is displayed.

Another suggested approach, which is based on giving the
--exit-code argument to git diff, cannot be used, because
diff-files seems to trust the timestamps in the index, and
returns a non-zero code even if the file is actually
unchanged, which essentially defeats the purpose of the
auto-rescan logic.

Signed-off-by: Alexander Gavrilov <angavrilov@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
2009-02-08 11:50:11 -08:00

653 lines
16 KiB
Tcl

# git-gui diff viewer
# Copyright (C) 2006, 2007 Shawn Pearce
proc clear_diff {} {
global ui_diff current_diff_path current_diff_header
global ui_index ui_workdir
$ui_diff conf -state normal
$ui_diff delete 0.0 end
$ui_diff conf -state disabled
set current_diff_path {}
set current_diff_header {}
$ui_index tag remove in_diff 0.0 end
$ui_workdir tag remove in_diff 0.0 end
}
proc reshow_diff {{after {}}} {
global file_states file_lists
global current_diff_path current_diff_side
global ui_diff
set p $current_diff_path
if {$p eq {}} {
# No diff is being shown.
} elseif {$current_diff_side eq {}} {
clear_diff
} elseif {[catch {set s $file_states($p)}]
|| [lsearch -sorted -exact $file_lists($current_diff_side) $p] == -1} {
if {[find_next_diff $current_diff_side $p {} {[^O]}]} {
next_diff $after
} else {
clear_diff
}
} else {
set save_pos [lindex [$ui_diff yview] 0]
show_diff $p $current_diff_side {} $save_pos $after
}
}
proc force_diff_encoding {enc} {
global current_diff_path
if {$current_diff_path ne {}} {
force_path_encoding $current_diff_path $enc
reshow_diff
}
}
proc handle_empty_diff {} {
global current_diff_path file_states file_lists
global diff_empty_count
set path $current_diff_path
set s $file_states($path)
if {[lindex $s 0] ne {_M}} return
# Prevent infinite rescan loops
incr diff_empty_count
if {$diff_empty_count > 1} return
info_popup [mc "No differences detected.
%s has no changes.
The modification date of this file was updated by another application, but the content within the file was not changed.
A rescan will be automatically started to find other files which may have the same state." [short_path $path]]
clear_diff
display_file $path __
rescan ui_ready 0
}
proc show_diff {path w {lno {}} {scroll_pos {}} {callback {}}} {
global file_states file_lists
global is_3way_diff is_conflict_diff diff_active repo_config
global ui_diff ui_index ui_workdir
global current_diff_path current_diff_side current_diff_header
global current_diff_queue
if {$diff_active || ![lock_index read]} return
clear_diff
if {$lno == {}} {
set lno [lsearch -sorted -exact $file_lists($w) $path]
if {$lno >= 0} {
incr lno
}
}
if {$lno >= 1} {
$w tag add in_diff $lno.0 [expr {$lno + 1}].0
$w see $lno.0
}
set s $file_states($path)
set m [lindex $s 0]
set is_conflict_diff 0
set current_diff_path $path
set current_diff_side $w
set current_diff_queue {}
ui_status [mc "Loading diff of %s..." [escape_path $path]]
set cont_info [list $scroll_pos $callback]
if {[string first {U} $m] >= 0} {
merge_load_stages $path [list show_unmerged_diff $cont_info]
} elseif {$m eq {_O}} {
show_other_diff $path $w $m $cont_info
} else {
start_show_diff $cont_info
}
}
proc show_unmerged_diff {cont_info} {
global current_diff_path current_diff_side
global merge_stages ui_diff is_conflict_diff
global current_diff_queue
if {$merge_stages(2) eq {}} {
set is_conflict_diff 1
lappend current_diff_queue \
[list [mc "LOCAL: deleted\nREMOTE:\n"] d======= \
[list ":1:$current_diff_path" ":3:$current_diff_path"]]
} elseif {$merge_stages(3) eq {}} {
set is_conflict_diff 1
lappend current_diff_queue \
[list [mc "REMOTE: deleted\nLOCAL:\n"] d======= \
[list ":1:$current_diff_path" ":2:$current_diff_path"]]
} elseif {[lindex $merge_stages(1) 0] eq {120000}
|| [lindex $merge_stages(2) 0] eq {120000}
|| [lindex $merge_stages(3) 0] eq {120000}} {
set is_conflict_diff 1
lappend current_diff_queue \
[list [mc "LOCAL:\n"] d======= \
[list ":1:$current_diff_path" ":2:$current_diff_path"]]
lappend current_diff_queue \
[list [mc "REMOTE:\n"] d======= \
[list ":1:$current_diff_path" ":3:$current_diff_path"]]
} else {
start_show_diff $cont_info
return
}
advance_diff_queue $cont_info
}
proc advance_diff_queue {cont_info} {
global current_diff_queue ui_diff
set item [lindex $current_diff_queue 0]
set current_diff_queue [lrange $current_diff_queue 1 end]
$ui_diff conf -state normal
$ui_diff insert end [lindex $item 0] [lindex $item 1]
$ui_diff conf -state disabled
start_show_diff $cont_info [lindex $item 2]
}
proc show_other_diff {path w m cont_info} {
global file_states file_lists
global is_3way_diff diff_active repo_config
global ui_diff ui_index ui_workdir
global current_diff_path current_diff_side current_diff_header
# - Git won't give us the diff, there's nothing to compare to!
#
if {$m eq {_O}} {
set max_sz 100000
set type unknown
if {[catch {
set type [file type $path]
switch -- $type {
directory {
set type submodule
set content {}
set sz 0
}
link {
set content [file readlink $path]
set sz [string length $content]
}
file {
set fd [open $path r]
fconfigure $fd \
-eofchar {} \
-encoding [get_path_encoding $path]
set content [read $fd $max_sz]
close $fd
set sz [file size $path]
}
default {
error "'$type' not supported"
}
}
} err ]} {
set diff_active 0
unlock_index
ui_status [mc "Unable to display %s" [escape_path $path]]
error_popup [strcat [mc "Error loading file:"] "\n\n$err"]
return
}
$ui_diff conf -state normal
if {$type eq {submodule}} {
$ui_diff insert end [append \
"* " \
[mc "Git Repository (subproject)"] \
"\n"] d_@
} elseif {![catch {set type [exec file $path]}]} {
set n [string length $path]
if {[string equal -length $n $path $type]} {
set type [string range $type $n end]
regsub {^:?\s*} $type {} type
}
$ui_diff insert end "* $type\n" d_@
}
if {[string first "\0" $content] != -1} {
$ui_diff insert end \
[mc "* Binary file (not showing content)."] \
d_@
} else {
if {$sz > $max_sz} {
$ui_diff insert end [mc \
"* Untracked file is %d bytes.
* Showing only first %d bytes.
" $sz $max_sz] d_@
}
$ui_diff insert end $content
if {$sz > $max_sz} {
$ui_diff insert end [mc "
* Untracked file clipped here by %s.
* To see the entire file, use an external editor.
" [appname]] d_@
}
}
$ui_diff conf -state disabled
set diff_active 0
unlock_index
set scroll_pos [lindex $cont_info 0]
if {$scroll_pos ne {}} {
update
$ui_diff yview moveto $scroll_pos
}
ui_ready
set callback [lindex $cont_info 1]
if {$callback ne {}} {
eval $callback
}
return
}
}
proc start_show_diff {cont_info {add_opts {}}} {
global file_states file_lists
global is_3way_diff diff_active repo_config
global ui_diff ui_index ui_workdir
global current_diff_path current_diff_side current_diff_header
set path $current_diff_path
set w $current_diff_side
set s $file_states($path)
set m [lindex $s 0]
set is_3way_diff 0
set diff_active 1
set current_diff_header {}
set cmd [list]
if {$w eq $ui_index} {
lappend cmd diff-index
lappend cmd --cached
} elseif {$w eq $ui_workdir} {
if {[string first {U} $m] >= 0} {
lappend cmd diff
} else {
lappend cmd diff-files
}
}
lappend cmd -p
lappend cmd --no-color
if {$repo_config(gui.diffcontext) >= 1} {
lappend cmd "-U$repo_config(gui.diffcontext)"
}
if {$w eq $ui_index} {
lappend cmd [PARENT]
}
if {$add_opts ne {}} {
eval lappend cmd $add_opts
} else {
lappend cmd --
lappend cmd $path
}
if {[catch {set fd [eval git_read --nice $cmd]} err]} {
set diff_active 0
unlock_index
ui_status [mc "Unable to display %s" [escape_path $path]]
error_popup [strcat [mc "Error loading diff:"] "\n\n$err"]
return
}
set ::current_diff_inheader 1
fconfigure $fd \
-blocking 0 \
-encoding [get_path_encoding $path] \
-translation lf
fileevent $fd readable [list read_diff $fd $cont_info]
}
proc read_diff {fd cont_info} {
global ui_diff diff_active
global is_3way_diff is_conflict_diff current_diff_header
global current_diff_queue
global diff_empty_count
$ui_diff conf -state normal
while {[gets $fd line] >= 0} {
# -- Cleanup uninteresting diff header lines.
#
if {$::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.
#
if {[string match {@@@ *} $line]} {set is_3way_diff 1}
if {[string match {mode *} $line]
|| [string match {new file *} $line]
|| [regexp {^(old|new) mode *} $line]
|| [string match {deleted file *} $line]
|| [string match {deleted symlink} $line]
|| [string match {Binary files * and * differ} $line]
|| $line eq {\ No newline at end of file}
|| [regexp {^\* Unmerged path } $line]} {
set tags {}
} elseif {$is_3way_diff} {
set op [string range $line 0 1]
switch -- $op {
{ } {set tags {}}
{@@} {set tags d_@}
{ +} {set tags d_s+}
{ -} {set tags d_s-}
{+ } {set tags d_+s}
{- } {set tags d_-s}
{--} {set tags d_--}
{++} {
if {[regexp {^\+\+([<>]{7} |={7})} $line _g op]} {
set is_conflict_diff 1
set line [string replace $line 0 1 { }]
set tags d$op
} else {
set tags d_++
}
}
default {
puts "error: Unhandled 3 way diff marker: {$op}"
set tags {}
}
}
} else {
set op [string index $line 0]
switch -- $op {
{ } {set tags {}}
{@} {set tags d_@}
{-} {set tags d_-}
{+} {
if {[regexp {^\+([<>]{7} |={7})} $line _g op]} {
set is_conflict_diff 1
set tags d$op
} else {
set tags d_+
}
}
default {
puts "error: Unhandled 2 way diff marker: {$op}"
set tags {}
}
}
}
$ui_diff insert end $line $tags
if {[string index $line end] eq "\r"} {
$ui_diff tag add d_cr {end - 2c}
}
$ui_diff insert end "\n" $tags
}
$ui_diff conf -state disabled
if {[eof $fd]} {
close $fd
if {$current_diff_queue ne {}} {
advance_diff_queue $cont_info
return
}
set diff_active 0
unlock_index
set scroll_pos [lindex $cont_info 0]
if {$scroll_pos ne {}} {
update
$ui_diff yview moveto $scroll_pos
}
ui_ready
if {[$ui_diff index end] eq {2.0}} {
handle_empty_diff
} else {
set diff_empty_count 0
}
set callback [lindex $cont_info 1]
if {$callback ne {}} {
eval $callback
}
}
}
proc apply_hunk {x y} {
global current_diff_path current_diff_header current_diff_side
global ui_diff ui_index file_states
if {$current_diff_path eq {} || $current_diff_header eq {}} return
if {![lock_index apply_hunk]} return
set apply_cmd {apply --cached --whitespace=nowarn}
set mi [lindex $file_states($current_diff_path) 0]
if {$current_diff_side eq $ui_index} {
set failed_msg [mc "Failed to unstage selected hunk."]
lappend apply_cmd --reverse
if {[string index $mi 0] ne {M}} {
unlock_index
return
}
} else {
set failed_msg [mc "Failed to stage selected hunk."]
if {[string index $mi 1] ne {M}} {
unlock_index
return
}
}
set s_lno [lindex [split [$ui_diff index @$x,$y] .] 0]
set s_lno [$ui_diff search -backwards -regexp ^@@ $s_lno.0 0.0]
if {$s_lno eq {}} {
unlock_index
return
}
set e_lno [$ui_diff search -forwards -regexp ^@@ "$s_lno + 1 lines" end]
if {$e_lno eq {}} {
set e_lno end
}
if {[catch {
set enc [get_path_encoding $current_diff_path]
set p [eval git_write $apply_cmd]
fconfigure $p -translation binary -encoding $enc
puts -nonewline $p $current_diff_header
puts -nonewline $p [$ui_diff get $s_lno $e_lno]
close $p} err]} {
error_popup [append $failed_msg "\n\n$err"]
unlock_index
return
}
$ui_diff conf -state normal
$ui_diff delete $s_lno $e_lno
$ui_diff conf -state disabled
if {[$ui_diff get 1.0 end] eq "\n"} {
set o _
} else {
set o ?
}
if {$current_diff_side eq $ui_index} {
set mi ${o}M
} elseif {[string index $mi 0] eq {_}} {
set mi M$o
} else {
set mi ?$o
}
unlock_index
display_file $current_diff_path $mi
# This should trigger shift to the next changed file
if {$o eq {_}} {
reshow_diff
}
}
proc apply_line {x y} {
global current_diff_path current_diff_header current_diff_side
global ui_diff ui_index file_states
if {$current_diff_path eq {} || $current_diff_header eq {}} return
if {![lock_index apply_hunk]} return
set apply_cmd {apply --cached --whitespace=nowarn}
set mi [lindex $file_states($current_diff_path) 0]
if {$current_diff_side eq $ui_index} {
set failed_msg [mc "Failed to unstage selected line."]
set to_context {+}
lappend apply_cmd --reverse
if {[string index $mi 0] ne {M}} {
unlock_index
return
}
} else {
set failed_msg [mc "Failed to stage selected line."]
set to_context {-}
if {[string index $mi 1] ne {M}} {
unlock_index
return
}
}
set the_l [$ui_diff index @$x,$y]
# operate only on change lines
set c1 [$ui_diff get "$the_l linestart"]
if {$c1 ne {+} && $c1 ne {-}} {
unlock_index
return
}
set sign $c1
set i_l [$ui_diff search -backwards -regexp ^@@ $the_l 0.0]
if {$i_l eq {}} {
unlock_index
return
}
# $i_l is now at the beginning of a line
# pick start line number from hunk header
set hh [$ui_diff get $i_l "$i_l + 1 lines"]
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 "$i_l + 1 lines"]
set patch {}
while {[$ui_diff compare $i_l < "end - 1 chars"] &&
[$ui_diff get $i_l "$i_l + 2 chars"] ne {@@}} {
set next_l [$ui_diff index "$i_l + 1 lines"]
set c1 [$ui_diff get $i_l]
if {[$ui_diff compare $i_l <= $the_l] &&
[$ui_diff compare $the_l < $next_l]} {
# the line to stage/unstage
set ln [$ui_diff get $i_l $next_l]
if {$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$pre_context$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" $next_l]
if {$c1 eq {-}} {
set pre_context "$pre_context $ln"
} else {
set patch "$patch $ln"
}
set n [expr $n+1]
}
set i_l $next_l
}
set patch "@@ -$hln,$n +$hln,[eval expr $n $sign 1] @@\n$patch"
if {[catch {
set enc [get_path_encoding $current_diff_path]
set p [eval git_write $apply_cmd]
fconfigure $p -translation binary -encoding $enc
puts -nonewline $p $current_diff_header
puts -nonewline $p $patch
close $p} err]} {
error_popup [append $failed_msg "\n\n$err"]
}
unlock_index
}