short circuit out of a few places where we would allocate zero bytes
[git.git] / diff-files.c
1 /*
2  * GIT - The information manager from hell
3  *
4  * Copyright (C) Linus Torvalds, 2005
5  */
6 #include "cache.h"
7 #include "diff.h"
8
9 static const char diff_files_usage[] =
10 "git-diff-files [-q] [-0/-1/2/3] [<common diff options>] [<path>...]"
11 COMMON_DIFF_OPTIONS_HELP;
12
13 static struct diff_options diff_options;
14 static int silent = 0;
15 static int diff_unmerged_stage = 2;
16
17 static void show_unmerge(const char *path)
18 {
19         diff_unmerge(&diff_options, path);
20 }
21
22 static void show_file(int pfx, struct cache_entry *ce)
23 {
24         diff_addremove(&diff_options, pfx, ntohl(ce->ce_mode),
25                        ce->sha1, ce->name, NULL);
26 }
27
28 static void show_modified(int oldmode, int mode,
29                           const unsigned char *old_sha1, const unsigned char *sha1,
30                           char *path)
31 {
32         diff_change(&diff_options, oldmode, mode, old_sha1, sha1, path, NULL);
33 }
34
35 int main(int argc, const char **argv)
36 {
37         const char **pathspec;
38         const char *prefix = setup_git_directory();
39         int entries, i;
40
41         git_config(git_diff_config);
42         diff_setup(&diff_options);
43         while (1 < argc && argv[1][0] == '-') {
44                 if (!strcmp(argv[1], "--")) {
45                         argv++;
46                         argc--;
47                         break;
48                 }
49                 if (!strcmp(argv[1], "-0"))
50                         diff_unmerged_stage = 0;
51                 else if (!strcmp(argv[1], "-1"))
52                         diff_unmerged_stage = 1;
53                 else if (!strcmp(argv[1], "-2"))
54                         diff_unmerged_stage = 2;
55                 else if (!strcmp(argv[1], "-3"))
56                         diff_unmerged_stage = 3;
57                 else if (!strcmp(argv[1], "--base"))
58                         diff_unmerged_stage = 1;
59                 else if (!strcmp(argv[1], "--ours"))
60                         diff_unmerged_stage = 2;
61                 else if (!strcmp(argv[1], "--theirs"))
62                         diff_unmerged_stage = 3;
63                 else if (!strcmp(argv[1], "-q"))
64                         silent = 1;
65                 else if (!strcmp(argv[1], "-r"))
66                         ; /* no-op */
67                 else if (!strcmp(argv[1], "-s"))
68                         ; /* no-op */
69                 else {
70                         int diff_opt_cnt;
71                         diff_opt_cnt = diff_opt_parse(&diff_options,
72                                                       argv+1, argc-1);
73                         if (diff_opt_cnt < 0)
74                                 usage(diff_files_usage);
75                         else if (diff_opt_cnt) {
76                                 argv += diff_opt_cnt;
77                                 argc -= diff_opt_cnt;
78                                 continue;
79                         }
80                         else
81                                 usage(diff_files_usage);
82                 }
83                 argv++; argc--;
84         }
85
86         /* Find the directory, and set up the pathspec */
87         pathspec = get_pathspec(prefix, argv + 1);
88         entries = read_cache();
89
90         if (diff_setup_done(&diff_options) < 0)
91                 usage(diff_files_usage);
92
93         /* At this point, if argc == 1, then we are doing everything.
94          * Otherwise argv[1] .. argv[argc-1] have the explicit paths.
95          */
96         if (entries < 0) {
97                 perror("read_cache");
98                 exit(1);
99         }
100
101         for (i = 0; i < entries; i++) {
102                 struct stat st;
103                 unsigned int oldmode, newmode;
104                 struct cache_entry *ce = active_cache[i];
105                 int changed;
106
107                 if (!ce_path_match(ce, pathspec))
108                         continue;
109
110                 if (ce_stage(ce)) {
111                         show_unmerge(ce->name);
112                         while (i < entries) {
113                                 struct cache_entry *nce = active_cache[i];
114
115                                 if (strcmp(ce->name, nce->name))
116                                         break;
117                                 /* diff against the proper unmerged stage */
118                                 if (ce_stage(nce) == diff_unmerged_stage)
119                                         ce = nce;
120                                 i++;
121                         }
122                         /*
123                          * Compensate for loop update
124                          */
125                         i--;
126                         /*
127                          * Show the diff for the 'ce' if we found the one
128                          * from the desired stage.
129                          */
130                         if (ce_stage(ce) != diff_unmerged_stage)
131                                 continue;
132                 }
133
134                 if (lstat(ce->name, &st) < 0) {
135                         if (errno != ENOENT && errno != ENOTDIR) {
136                                 perror(ce->name);
137                                 continue;
138                         }
139                         if (silent)
140                                 continue;
141                         show_file('-', ce);
142                         continue;
143                 }
144                 changed = ce_match_stat(ce, &st);
145                 if (!changed && !diff_options.find_copies_harder)
146                         continue;
147                 oldmode = ntohl(ce->ce_mode);
148
149                 newmode = DIFF_FILE_CANON_MODE(st.st_mode);
150                 if (!trust_executable_bit &&
151                     S_ISREG(newmode) && S_ISREG(oldmode) &&
152                     ((newmode ^ oldmode) == 0111))
153                         newmode = oldmode;
154                 show_modified(oldmode, newmode,
155                               ce->sha1, (changed ? null_sha1 : ce->sha1),
156                               ce->name);
157         }
158         diffcore_std(&diff_options);
159         diff_flush(&diff_options);
160         return 0;
161 }