Merge branch 'jn/do-not-drop-username-when-reading-from-etc-mailname'
[git] / builtin / replace.c
1 /*
2  * Builtin "git replace"
3  *
4  * Copyright (c) 2008 Christian Couder <chriscool@tuxfamily.org>
5  *
6  * Based on builtin-tag.c by Kristian Høgsberg <krh@redhat.com>
7  * and Carlos Rica <jasampler@gmail.com> that was itself based on
8  * git-tag.sh and mktag.c by Linus Torvalds.
9  */
10
11 #include "cache.h"
12 #include "builtin.h"
13 #include "refs.h"
14 #include "parse-options.h"
15
16 static const char * const git_replace_usage[] = {
17         N_("git replace [-f] <object> <replacement>"),
18         N_("git replace -d <object>..."),
19         N_("git replace -l [<pattern>]"),
20         NULL
21 };
22
23 static int show_reference(const char *refname, const unsigned char *sha1,
24                           int flag, void *cb_data)
25 {
26         const char *pattern = cb_data;
27
28         if (!fnmatch(pattern, refname, 0))
29                 printf("%s\n", refname);
30
31         return 0;
32 }
33
34 static int list_replace_refs(const char *pattern)
35 {
36         if (pattern == NULL)
37                 pattern = "*";
38
39         for_each_replace_ref(show_reference, (void *) pattern);
40
41         return 0;
42 }
43
44 typedef int (*each_replace_name_fn)(const char *name, const char *ref,
45                                     const unsigned char *sha1);
46
47 static int for_each_replace_name(const char **argv, each_replace_name_fn fn)
48 {
49         const char **p, *full_hex;
50         char ref[PATH_MAX];
51         int had_error = 0;
52         unsigned char sha1[20];
53
54         for (p = argv; *p; p++) {
55                 if (get_sha1(*p, sha1)) {
56                         error("Failed to resolve '%s' as a valid ref.", *p);
57                         had_error = 1;
58                         continue;
59                 }
60                 full_hex = sha1_to_hex(sha1);
61                 snprintf(ref, sizeof(ref), "refs/replace/%s", full_hex);
62                 /* read_ref() may reuse the buffer */
63                 full_hex = ref + strlen("refs/replace/");
64                 if (read_ref(ref, sha1)) {
65                         error("replace ref '%s' not found.", full_hex);
66                         had_error = 1;
67                         continue;
68                 }
69                 if (fn(full_hex, ref, sha1))
70                         had_error = 1;
71         }
72         return had_error;
73 }
74
75 static int delete_replace_ref(const char *name, const char *ref,
76                               const unsigned char *sha1)
77 {
78         if (delete_ref(ref, sha1, 0))
79                 return 1;
80         printf("Deleted replace ref '%s'\n", name);
81         return 0;
82 }
83
84 static int replace_object(const char *object_ref, const char *replace_ref,
85                           int force)
86 {
87         unsigned char object[20], prev[20], repl[20];
88         char ref[PATH_MAX];
89         struct ref_lock *lock;
90
91         if (get_sha1(object_ref, object))
92                 die("Failed to resolve '%s' as a valid ref.", object_ref);
93         if (get_sha1(replace_ref, repl))
94                 die("Failed to resolve '%s' as a valid ref.", replace_ref);
95
96         if (snprintf(ref, sizeof(ref),
97                      "refs/replace/%s",
98                      sha1_to_hex(object)) > sizeof(ref) - 1)
99                 die("replace ref name too long: %.*s...", 50, ref);
100         if (check_refname_format(ref, 0))
101                 die("'%s' is not a valid ref name.", ref);
102
103         if (read_ref(ref, prev))
104                 hashclr(prev);
105         else if (!force)
106                 die("replace ref '%s' already exists", ref);
107
108         lock = lock_any_ref_for_update(ref, prev, 0);
109         if (!lock)
110                 die("%s: cannot lock the ref", ref);
111         if (write_ref_sha1(lock, repl, NULL) < 0)
112                 die("%s: cannot update the ref", ref);
113
114         return 0;
115 }
116
117 int cmd_replace(int argc, const char **argv, const char *prefix)
118 {
119         int list = 0, delete = 0, force = 0;
120         struct option options[] = {
121                 OPT_BOOLEAN('l', NULL, &list, N_("list replace refs")),
122                 OPT_BOOLEAN('d', NULL, &delete, N_("delete replace refs")),
123                 OPT_BOOLEAN('f', NULL, &force, N_("replace the ref if it exists")),
124                 OPT_END()
125         };
126
127         argc = parse_options(argc, argv, prefix, options, git_replace_usage, 0);
128
129         if (list && delete)
130                 usage_msg_opt("-l and -d cannot be used together",
131                               git_replace_usage, options);
132
133         if (force && (list || delete))
134                 usage_msg_opt("-f cannot be used with -d or -l",
135                               git_replace_usage, options);
136
137         /* Delete refs */
138         if (delete) {
139                 if (argc < 1)
140                         usage_msg_opt("-d needs at least one argument",
141                                       git_replace_usage, options);
142                 return for_each_replace_name(argv, delete_replace_ref);
143         }
144
145         /* Replace object */
146         if (!list && argc) {
147                 if (argc != 2)
148                         usage_msg_opt("bad number of arguments",
149                                       git_replace_usage, options);
150                 return replace_object(argv[0], argv[1], force);
151         }
152
153         /* List refs, even if "list" is not set */
154         if (argc > 1)
155                 usage_msg_opt("only one pattern can be given with -l",
156                               git_replace_usage, options);
157         if (force)
158                 usage_msg_opt("-f needs some arguments",
159                               git_replace_usage, options);
160
161         return list_replace_refs(argv[0]);
162 }