docs/format-patch: mention handling of merges
[git] / builtin / merge-file.c
1 #include "builtin.h"
2 #include "cache.h"
3 #include "config.h"
4 #include "xdiff/xdiff.h"
5 #include "xdiff-interface.h"
6 #include "parse-options.h"
7
8 static const char *const merge_file_usage[] = {
9         N_("git merge-file [<options>] [-L <name1> [-L <orig> [-L <name2>]]] <file1> <orig-file> <file2>"),
10         NULL
11 };
12
13 static int label_cb(const struct option *opt, const char *arg, int unset)
14 {
15         static int label_count = 0;
16         const char **names = (const char **)opt->value;
17
18         BUG_ON_OPT_NEG(unset);
19
20         if (label_count >= 3)
21                 return error("too many labels on the command line");
22         names[label_count++] = arg;
23         return 0;
24 }
25
26 int cmd_merge_file(int argc, const char **argv, const char *prefix)
27 {
28         const char *names[3] = { NULL, NULL, NULL };
29         mmfile_t mmfs[3];
30         mmbuffer_t result = {NULL, 0};
31         xmparam_t xmp = {{0}};
32         int ret = 0, i = 0, to_stdout = 0;
33         int quiet = 0;
34         struct option options[] = {
35                 OPT_BOOL('p', "stdout", &to_stdout, N_("send results to standard output")),
36                 OPT_SET_INT(0, "diff3", &xmp.style, N_("use a diff3 based merge"), XDL_MERGE_DIFF3),
37                 OPT_SET_INT(0, "ours", &xmp.favor, N_("for conflicts, use our version"),
38                             XDL_MERGE_FAVOR_OURS),
39                 OPT_SET_INT(0, "theirs", &xmp.favor, N_("for conflicts, use their version"),
40                             XDL_MERGE_FAVOR_THEIRS),
41                 OPT_SET_INT(0, "union", &xmp.favor, N_("for conflicts, use a union version"),
42                             XDL_MERGE_FAVOR_UNION),
43                 OPT_INTEGER(0, "marker-size", &xmp.marker_size,
44                             N_("for conflicts, use this marker size")),
45                 OPT__QUIET(&quiet, N_("do not warn about conflicts")),
46                 OPT_CALLBACK('L', NULL, names, N_("name"),
47                              N_("set labels for file1/orig-file/file2"), &label_cb),
48                 OPT_END(),
49         };
50
51         xmp.level = XDL_MERGE_ZEALOUS_ALNUM;
52         xmp.style = 0;
53         xmp.favor = 0;
54
55         if (startup_info->have_repository) {
56                 /* Read the configuration file */
57                 git_config(git_xmerge_config, NULL);
58                 if (0 <= git_xmerge_style)
59                         xmp.style = git_xmerge_style;
60         }
61
62         argc = parse_options(argc, argv, prefix, options, merge_file_usage, 0);
63         if (argc != 3)
64                 usage_with_options(merge_file_usage, options);
65         if (quiet) {
66                 if (!freopen("/dev/null", "w", stderr))
67                         return error_errno("failed to redirect stderr to /dev/null");
68         }
69
70         for (i = 0; i < 3; i++) {
71                 char *fname;
72                 int ret;
73
74                 if (!names[i])
75                         names[i] = argv[i];
76
77                 fname = prefix_filename(prefix, argv[i]);
78                 ret = read_mmfile(mmfs + i, fname);
79                 free(fname);
80                 if (ret)
81                         return -1;
82
83                 if (mmfs[i].size > MAX_XDIFF_SIZE ||
84                     buffer_is_binary(mmfs[i].ptr, mmfs[i].size))
85                         return error("Cannot merge binary files: %s",
86                                         argv[i]);
87         }
88
89         xmp.ancestor = names[1];
90         xmp.file1 = names[0];
91         xmp.file2 = names[2];
92         ret = xdl_merge(mmfs + 1, mmfs + 0, mmfs + 2, &xmp, &result);
93
94         for (i = 0; i < 3; i++)
95                 free(mmfs[i].ptr);
96
97         if (ret >= 0) {
98                 const char *filename = argv[0];
99                 char *fpath = prefix_filename(prefix, argv[0]);
100                 FILE *f = to_stdout ? stdout : fopen(fpath, "wb");
101
102                 if (!f)
103                         ret = error_errno("Could not open %s for writing",
104                                           filename);
105                 else if (result.size &&
106                          fwrite(result.ptr, result.size, 1, f) != 1)
107                         ret = error_errno("Could not write to %s", filename);
108                 else if (fclose(f))
109                         ret = error_errno("Could not close %s", filename);
110                 free(result.ptr);
111                 free(fpath);
112         }
113
114         if (ret > 127)
115                 ret = 127;
116
117         return ret;
118 }