Merge branch 'js/typofixes'
[git] / Documentation / doc-diff
1 #!/bin/sh
2
3 OPTIONS_SPEC="\
4 doc-diff [options] <from> <to> [-- <diff-options>]
5 --
6 j=n     parallel argument to pass to make
7 f       force rebuild; do not rely on cached results
8 "
9 SUBDIRECTORY_OK=1
10 . "$(git --exec-path)/git-sh-setup"
11
12 parallel=
13 force=
14 while test $# -gt 0
15 do
16         case "$1" in
17         -j)
18                 parallel=$2; shift ;;
19         -f)
20                 force=t ;;
21         --)
22                 shift; break ;;
23         *)
24                 usage ;;
25         esac
26         shift
27 done
28
29 if test -z "$parallel"
30 then
31         parallel=$(getconf _NPROCESSORS_ONLN 2>/dev/null)
32         if test $? != 0 || test -z "$parallel"
33         then
34                 parallel=1
35         fi
36 fi
37
38 test $# -gt 1 || usage
39 from=$1; shift
40 to=$1; shift
41
42 from_oid=$(git rev-parse --verify "$from") || exit 1
43 to_oid=$(git rev-parse --verify "$to") || exit 1
44
45 cd_to_toplevel
46 tmp=Documentation/tmp-doc-diff
47
48 if test -n "$force"
49 then
50         rm -rf "$tmp"
51 fi
52
53 # We'll do both builds in a single worktree, which lets "make" reuse
54 # results that don't differ between the two trees.
55 if ! test -d "$tmp/worktree"
56 then
57         git worktree add --detach "$tmp/worktree" "$from" &&
58         dots=$(echo "$tmp/worktree" | sed 's#[^/]*#..#g') &&
59         ln -s "$dots/config.mak" "$tmp/worktree/config.mak"
60 fi
61
62 # generate_render_makefile <srcdir> <dstdir>
63 generate_render_makefile () {
64         find "$1" -type f |
65         while read src
66         do
67                 dst=$2/${src#$1/}
68                 printf 'all:: %s\n' "$dst"
69                 printf '%s: %s\n' "$dst" "$src"
70                 printf '\t@echo >&2 "  RENDER $(notdir $@)" && \\\n'
71                 printf '\tmkdir -p $(dir $@) && \\\n'
72                 printf '\tMANWIDTH=80 man -l $< >$@+ && \\\n'
73                 printf '\tmv $@+ $@\n'
74         done
75 }
76
77 # render_tree <dirname> <committish>
78 render_tree () {
79         # Skip install-man entirely if we already have an installed directory.
80         # We can't rely on make here, since "install-man" unconditionally
81         # copies the files (spending effort, but also updating timestamps that
82         # we then can't rely on during the render step). We use "mv" to make
83         # sure we don't get confused by a previous run that failed partway
84         # through.
85         if ! test -d "$tmp/installed/$1"
86         then
87                 git -C "$tmp/worktree" checkout "$2" &&
88                 make -j$parallel -C "$tmp/worktree" \
89                         GIT_VERSION=omitted \
90                         SOURCE_DATE_EPOCH=0 \
91                         DESTDIR="$PWD/$tmp/installed/$1+" \
92                         install-man &&
93                 mv "$tmp/installed/$1+" "$tmp/installed/$1"
94         fi &&
95
96         # As with "installed" above, we skip the render if it's already been
97         # done.  So using make here is primarily just about running in
98         # parallel.
99         if ! test -d "$tmp/rendered/$1"
100         then
101                 generate_render_makefile "$tmp/installed/$1" "$tmp/rendered/$1+" |
102                 make -j$parallel -f - &&
103                 mv "$tmp/rendered/$1+" "$tmp/rendered/$1"
104         fi
105 }
106
107 render_tree $from_oid "$from" &&
108 render_tree $to_oid "$to" &&
109 git -C $tmp/rendered diff --no-index "$@" $from_oid $to_oid