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8389b52b JH |
1 | #!/usr/bin/perl |
2 | # | |
3 | # REuse REcorded REsolve. This tool records a conflicted automerge | |
4 | # result and its hand resolution, and helps to resolve future | |
5 | # automerge that results in the same conflict. | |
6 | # | |
7 | # To enable this feature, create a directory 'rr-cache' under your | |
8 | # .git/ directory. | |
9 | ||
10 | use Digest; | |
11 | use File::Path; | |
12 | use File::Copy; | |
13 | ||
14 | my $git_dir = $::ENV{GIT_DIR} || ".git"; | |
15 | my $rr_dir = "$git_dir/rr-cache"; | |
16 | my $merge_rr = "$git_dir/rr-cache/MERGE_RR"; | |
17 | ||
18 | my %merge_rr = (); | |
19 | ||
20 | sub read_rr { | |
21 | if (!-f $merge_rr) { | |
22 | %merge_rr = (); | |
23 | return; | |
24 | } | |
25 | my $in; | |
26 | local $/ = "\0"; | |
27 | open $in, "<$merge_rr" or die "$!: $merge_rr"; | |
28 | while (<$in>) { | |
29 | chomp; | |
30 | my ($name, $path) = /^([0-9a-f]{40})\t(.*)$/s; | |
31 | $merge_rr{$path} = $name; | |
32 | } | |
33 | close $in; | |
34 | } | |
35 | ||
36 | sub write_rr { | |
37 | my $out; | |
38 | open $out, ">$merge_rr" or die "$!: $merge_rr"; | |
39 | for my $path (sort keys %merge_rr) { | |
40 | my $name = $merge_rr{$path}; | |
41 | print $out "$name\t$path\0"; | |
42 | } | |
43 | close $out; | |
44 | } | |
45 | ||
46 | sub compute_conflict_name { | |
47 | my ($path) = @_; | |
48 | my @side = (); | |
49 | my $in; | |
50 | open $in, "<$path" or die "$!: $path"; | |
51 | ||
52 | my $sha1 = Digest->new("SHA-1"); | |
53 | my $hunk = 0; | |
54 | while (<$in>) { | |
55 | if (/^<<<<<<< .*/) { | |
56 | $hunk++; | |
57 | @side = ([], undef); | |
58 | } | |
59 | elsif (/^=======$/) { | |
60 | $side[1] = []; | |
61 | } | |
62 | elsif (/^>>>>>>> .*/) { | |
63 | my ($one, $two); | |
64 | $one = join('', @{$side[0]}); | |
65 | $two = join('', @{$side[1]}); | |
66 | if ($two le $one) { | |
67 | ($one, $two) = ($two, $one); | |
68 | } | |
69 | $sha1->add($one); | |
70 | $sha1->add("\0"); | |
71 | $sha1->add($two); | |
72 | $sha1->add("\0"); | |
73 | @side = (); | |
74 | } | |
75 | elsif (@side == 0) { | |
76 | next; | |
77 | } | |
78 | elsif (defined $side[1]) { | |
79 | push @{$side[1]}, $_; | |
80 | } | |
81 | else { | |
82 | push @{$side[0]}, $_; | |
83 | } | |
84 | } | |
85 | close $in; | |
86 | return ($sha1->hexdigest, $hunk); | |
87 | } | |
88 | ||
89 | sub record_preimage { | |
90 | my ($path, $name) = @_; | |
91 | my @side = (); | |
92 | my ($in, $out); | |
93 | open $in, "<$path" or die "$!: $path"; | |
94 | open $out, ">$name" or die "$!: $name"; | |
95 | ||
96 | while (<$in>) { | |
97 | if (/^<<<<<<< .*/) { | |
98 | @side = ([], undef); | |
99 | } | |
100 | elsif (/^=======$/) { | |
101 | $side[1] = []; | |
102 | } | |
103 | elsif (/^>>>>>>> .*/) { | |
104 | my ($one, $two); | |
105 | $one = join('', @{$side[0]}); | |
106 | $two = join('', @{$side[1]}); | |
107 | if ($two le $one) { | |
108 | ($one, $two) = ($two, $one); | |
109 | } | |
110 | print $out "<<<<<<<\n"; | |
111 | print $out $one; | |
112 | print $out "=======\n"; | |
113 | print $out $two; | |
114 | print $out ">>>>>>>\n"; | |
115 | @side = (); | |
116 | } | |
117 | elsif (@side == 0) { | |
118 | print $out $_; | |
119 | } | |
120 | elsif (defined $side[1]) { | |
121 | push @{$side[1]}, $_; | |
122 | } | |
123 | else { | |
124 | push @{$side[0]}, $_; | |
125 | } | |
126 | } | |
127 | close $out; | |
128 | close $in; | |
129 | } | |
130 | ||
131 | sub find_conflict { | |
132 | my $in; | |
133 | local $/ = "\0"; | |
fedd273b JH |
134 | my $pid = open($in, '-|'); |
135 | die "$!" unless defined $pid; | |
136 | if (!$pid) { | |
137 | exec(qw(git ls-files -z -u)) or die "$!: ls-files"; | |
138 | } | |
8389b52b JH |
139 | my %path = (); |
140 | my @path = (); | |
141 | while (<$in>) { | |
142 | chomp; | |
143 | my ($mode, $sha1, $stage, $path) = | |
144 | /^([0-7]+) ([0-9a-f]{40}) ([123])\t(.*)$/s; | |
145 | $path{$path} |= (1 << $stage); | |
146 | } | |
147 | close $in; | |
148 | while (my ($path, $status) = each %path) { | |
149 | if ($status == 14) { push @path, $path; } | |
150 | } | |
151 | return @path; | |
152 | } | |
153 | ||
154 | sub merge { | |
155 | my ($name, $path) = @_; | |
156 | record_preimage($path, "$rr_dir/$name/thisimage"); | |
8336afa5 | 157 | unless (system('git', 'merge-file', map { "$rr_dir/$name/${_}image" } |
8389b52b JH |
158 | qw(this pre post))) { |
159 | my $in; | |
160 | open $in, "<$rr_dir/$name/thisimage" or | |
161 | die "$!: $name/thisimage"; | |
162 | my $out; | |
163 | open $out, ">$path" or die "$!: $path"; | |
164 | while (<$in>) { print $out $_; } | |
165 | close $in; | |
166 | close $out; | |
167 | return 1; | |
168 | } | |
169 | return 0; | |
170 | } | |
171 | ||
cda2d3c1 JH |
172 | sub garbage_collect_rerere { |
173 | # We should allow specifying these from the command line and | |
174 | # that is why the caller gives @ARGV to us, but I am lazy. | |
175 | ||
176 | my $cutoff_noresolve = 15; # two weeks | |
177 | my $cutoff_resolve = 60; # two months | |
178 | my @to_remove; | |
179 | while (<$rr_dir/*/preimage>) { | |
180 | my ($dir) = /^(.*)\/preimage$/; | |
181 | my $cutoff = ((-f "$dir/postimage") | |
182 | ? $cutoff_resolve | |
183 | : $cutoff_noresolve); | |
184 | my $age = -M "$_"; | |
185 | if ($cutoff <= $age) { | |
186 | push @to_remove, $dir; | |
187 | } | |
188 | } | |
189 | if (@to_remove) { | |
190 | rmtree(\@to_remove); | |
191 | } | |
192 | } | |
193 | ||
8389b52b JH |
194 | -d "$rr_dir" || exit(0); |
195 | ||
196 | read_rr(); | |
d9671b75 EW |
197 | |
198 | if (@ARGV) { | |
199 | my $arg = shift @ARGV; | |
200 | if ($arg eq 'clear') { | |
201 | for my $path (keys %merge_rr) { | |
202 | my $name = $merge_rr{$path}; | |
203 | if (-d "$rr_dir/$name" && | |
204 | ! -f "$rr_dir/$name/postimage") { | |
205 | rmtree(["$rr_dir/$name"]); | |
206 | } | |
207 | } | |
208 | unlink $merge_rr; | |
209 | } | |
210 | elsif ($arg eq 'status') { | |
211 | for my $path (keys %merge_rr) { | |
212 | print $path, "\n"; | |
213 | } | |
214 | } | |
215 | elsif ($arg eq 'diff') { | |
216 | for my $path (keys %merge_rr) { | |
217 | my $name = $merge_rr{$path}; | |
218 | system('diff', ((@ARGV == 0) ? ('-u') : @ARGV), | |
219 | '-L', "a/$path", '-L', "b/$path", | |
220 | "$rr_dir/$name/preimage", $path); | |
221 | } | |
222 | } | |
cda2d3c1 JH |
223 | elsif ($arg eq 'gc') { |
224 | garbage_collect_rerere(@ARGV); | |
225 | } | |
d9671b75 EW |
226 | else { |
227 | die "$0 unknown command: $arg\n"; | |
228 | } | |
229 | exit 0; | |
230 | } | |
231 | ||
8389b52b JH |
232 | my %conflict = map { $_ => 1 } find_conflict(); |
233 | ||
234 | # MERGE_RR records paths with conflicts immediately after merge | |
235 | # failed. Some of the conflicted paths might have been hand resolved | |
236 | # in the working tree since then, but the initial run would catch all | |
237 | # and register their preimages. | |
238 | ||
239 | for my $path (keys %conflict) { | |
240 | # This path has conflict. If it is not recorded yet, | |
241 | # record the pre-image. | |
242 | if (!exists $merge_rr{$path}) { | |
243 | my ($name, $hunk) = compute_conflict_name($path); | |
244 | next unless ($hunk); | |
245 | $merge_rr{$path} = $name; | |
246 | if (! -d "$rr_dir/$name") { | |
247 | mkpath("$rr_dir/$name", 0, 0777); | |
248 | print STDERR "Recorded preimage for '$path'\n"; | |
249 | record_preimage($path, "$rr_dir/$name/preimage"); | |
250 | } | |
251 | } | |
252 | } | |
253 | ||
254 | # Now some of the paths that had conflicts earlier might have been | |
255 | # hand resolved. Others may be similar to a conflict already that | |
256 | # was resolved before. | |
257 | ||
258 | for my $path (keys %merge_rr) { | |
259 | my $name = $merge_rr{$path}; | |
260 | ||
261 | # We could resolve this automatically if we have images. | |
262 | if (-f "$rr_dir/$name/preimage" && | |
263 | -f "$rr_dir/$name/postimage") { | |
264 | if (merge($name, $path)) { | |
265 | print STDERR "Resolved '$path' using previous resolution.\n"; | |
266 | # Then we do not have to worry about this path | |
267 | # anymore. | |
268 | delete $merge_rr{$path}; | |
269 | next; | |
270 | } | |
271 | } | |
272 | ||
273 | # Let's see if we have resolved it. | |
274 | (undef, my $hunk) = compute_conflict_name($path); | |
275 | next if ($hunk); | |
276 | ||
277 | print STDERR "Recorded resolution for '$path'.\n"; | |
278 | copy($path, "$rr_dir/$name/postimage"); | |
279 | # And we do not have to worry about this path anymore. | |
280 | delete $merge_rr{$path}; | |
281 | } | |
282 | ||
283 | # Write out the rest. | |
284 | write_rr(); |