Merge branch 'jk/p5302-avoid-collision-check-cost'
[git] / diff-no-index.c
1 /*
2  * "diff --no-index" support
3  * Copyright (c) 2007 by Johannes Schindelin
4  * Copyright (c) 2008 by Junio C Hamano
5  */
6
7 #include "cache.h"
8 #include "color.h"
9 #include "commit.h"
10 #include "blob.h"
11 #include "tag.h"
12 #include "diff.h"
13 #include "diffcore.h"
14 #include "revision.h"
15 #include "log-tree.h"
16 #include "builtin.h"
17 #include "parse-options.h"
18 #include "string-list.h"
19 #include "dir.h"
20
21 static int read_directory_contents(const char *path, struct string_list *list)
22 {
23         DIR *dir;
24         struct dirent *e;
25
26         if (!(dir = opendir(path)))
27                 return error("Could not open directory %s", path);
28
29         while ((e = readdir(dir)))
30                 if (!is_dot_or_dotdot(e->d_name))
31                         string_list_insert(list, e->d_name);
32
33         closedir(dir);
34         return 0;
35 }
36
37 /*
38  * This should be "(standard input)" or something, but it will
39  * probably expose many more breakages in the way no-index code
40  * is bolted onto the diff callchain.
41  */
42 static const char file_from_standard_input[] = "-";
43
44 static int get_mode(const char *path, int *mode)
45 {
46         struct stat st;
47
48         if (!path || !strcmp(path, "/dev/null"))
49                 *mode = 0;
50 #ifdef GIT_WINDOWS_NATIVE
51         else if (!strcasecmp(path, "nul"))
52                 *mode = 0;
53 #endif
54         else if (path == file_from_standard_input)
55                 *mode = create_ce_mode(0666);
56         else if (lstat(path, &st))
57                 return error("Could not access '%s'", path);
58         else
59                 *mode = st.st_mode;
60         return 0;
61 }
62
63 static int populate_from_stdin(struct diff_filespec *s)
64 {
65         struct strbuf buf = STRBUF_INIT;
66         size_t size = 0;
67
68         if (strbuf_read(&buf, 0, 0) < 0)
69                 return error_errno("error while reading from stdin");
70
71         s->should_munmap = 0;
72         s->data = strbuf_detach(&buf, &size);
73         s->size = size;
74         s->should_free = 1;
75         s->is_stdin = 1;
76         return 0;
77 }
78
79 static struct diff_filespec *noindex_filespec(const char *name, int mode)
80 {
81         struct diff_filespec *s;
82
83         if (!name)
84                 name = "/dev/null";
85         s = alloc_filespec(name);
86         fill_filespec(s, &null_oid, 0, mode);
87         if (name == file_from_standard_input)
88                 populate_from_stdin(s);
89         return s;
90 }
91
92 static int queue_diff(struct diff_options *o,
93                       const char *name1, const char *name2)
94 {
95         int mode1 = 0, mode2 = 0;
96
97         if (get_mode(name1, &mode1) || get_mode(name2, &mode2))
98                 return -1;
99
100         if (mode1 && mode2 && S_ISDIR(mode1) != S_ISDIR(mode2)) {
101                 struct diff_filespec *d1, *d2;
102
103                 if (S_ISDIR(mode1)) {
104                         /* 2 is file that is created */
105                         d1 = noindex_filespec(NULL, 0);
106                         d2 = noindex_filespec(name2, mode2);
107                         name2 = NULL;
108                         mode2 = 0;
109                 } else {
110                         /* 1 is file that is deleted */
111                         d1 = noindex_filespec(name1, mode1);
112                         d2 = noindex_filespec(NULL, 0);
113                         name1 = NULL;
114                         mode1 = 0;
115                 }
116                 /* emit that file */
117                 diff_queue(&diff_queued_diff, d1, d2);
118
119                 /* and then let the entire directory be created or deleted */
120         }
121
122         if (S_ISDIR(mode1) || S_ISDIR(mode2)) {
123                 struct strbuf buffer1 = STRBUF_INIT;
124                 struct strbuf buffer2 = STRBUF_INIT;
125                 struct string_list p1 = STRING_LIST_INIT_DUP;
126                 struct string_list p2 = STRING_LIST_INIT_DUP;
127                 int i1, i2, ret = 0;
128                 size_t len1 = 0, len2 = 0;
129
130                 if (name1 && read_directory_contents(name1, &p1))
131                         return -1;
132                 if (name2 && read_directory_contents(name2, &p2)) {
133                         string_list_clear(&p1, 0);
134                         return -1;
135                 }
136
137                 if (name1) {
138                         strbuf_addstr(&buffer1, name1);
139                         strbuf_complete(&buffer1, '/');
140                         len1 = buffer1.len;
141                 }
142
143                 if (name2) {
144                         strbuf_addstr(&buffer2, name2);
145                         strbuf_complete(&buffer2, '/');
146                         len2 = buffer2.len;
147                 }
148
149                 for (i1 = i2 = 0; !ret && (i1 < p1.nr || i2 < p2.nr); ) {
150                         const char *n1, *n2;
151                         int comp;
152
153                         strbuf_setlen(&buffer1, len1);
154                         strbuf_setlen(&buffer2, len2);
155
156                         if (i1 == p1.nr)
157                                 comp = 1;
158                         else if (i2 == p2.nr)
159                                 comp = -1;
160                         else
161                                 comp = strcmp(p1.items[i1].string, p2.items[i2].string);
162
163                         if (comp > 0)
164                                 n1 = NULL;
165                         else {
166                                 strbuf_addstr(&buffer1, p1.items[i1++].string);
167                                 n1 = buffer1.buf;
168                         }
169
170                         if (comp < 0)
171                                 n2 = NULL;
172                         else {
173                                 strbuf_addstr(&buffer2, p2.items[i2++].string);
174                                 n2 = buffer2.buf;
175                         }
176
177                         ret = queue_diff(o, n1, n2);
178                 }
179                 string_list_clear(&p1, 0);
180                 string_list_clear(&p2, 0);
181                 strbuf_release(&buffer1);
182                 strbuf_release(&buffer2);
183
184                 return ret;
185         } else {
186                 struct diff_filespec *d1, *d2;
187
188                 if (o->flags.reverse_diff) {
189                         SWAP(mode1, mode2);
190                         SWAP(name1, name2);
191                 }
192
193                 d1 = noindex_filespec(name1, mode1);
194                 d2 = noindex_filespec(name2, mode2);
195                 diff_queue(&diff_queued_diff, d1, d2);
196                 return 0;
197         }
198 }
199
200 /* append basename of F to D */
201 static void append_basename(struct strbuf *path, const char *dir, const char *file)
202 {
203         const char *tail = strrchr(file, '/');
204
205         strbuf_addstr(path, dir);
206         while (path->len && path->buf[path->len - 1] == '/')
207                 path->len--;
208         strbuf_addch(path, '/');
209         strbuf_addstr(path, tail ? tail + 1 : file);
210 }
211
212 /*
213  * DWIM "diff D F" into "diff D/F F" and "diff F D" into "diff F D/F"
214  * Note that we append the basename of F to D/, so "diff a/b/file D"
215  * becomes "diff a/b/file D/file", not "diff a/b/file D/a/b/file".
216  */
217 static void fixup_paths(const char **path, struct strbuf *replacement)
218 {
219         unsigned int isdir0, isdir1;
220
221         if (path[0] == file_from_standard_input ||
222             path[1] == file_from_standard_input)
223                 return;
224         isdir0 = is_directory(path[0]);
225         isdir1 = is_directory(path[1]);
226         if (isdir0 == isdir1)
227                 return;
228         if (isdir0) {
229                 append_basename(replacement, path[0], path[1]);
230                 path[0] = replacement->buf;
231         } else {
232                 append_basename(replacement, path[1], path[0]);
233                 path[1] = replacement->buf;
234         }
235 }
236
237 static const char * const diff_no_index_usage[] = {
238         N_("git diff --no-index [<options>] <path> <path>"),
239         NULL
240 };
241
242 int diff_no_index(struct rev_info *revs,
243                   int implicit_no_index,
244                   int argc, const char **argv)
245 {
246         int i, no_index;
247         const char *paths[2];
248         struct strbuf replacement = STRBUF_INIT;
249         const char *prefix = revs->prefix;
250         struct option no_index_options[] = {
251                 OPT_BOOL_F(0, "no-index", &no_index, "",
252                            PARSE_OPT_NONEG | PARSE_OPT_HIDDEN),
253                 OPT_END(),
254         };
255         struct option *options;
256
257         options = parse_options_concat(no_index_options,
258                                        revs->diffopt.parseopts);
259         argc = parse_options(argc, argv, revs->prefix, options,
260                              diff_no_index_usage, 0);
261         if (argc != 2) {
262                 if (implicit_no_index)
263                         warning(_("Not a git repository. Use --no-index to "
264                                   "compare two paths outside a working tree"));
265                 usage_with_options(diff_no_index_usage, options);
266         }
267         FREE_AND_NULL(options);
268         for (i = 0; i < 2; i++) {
269                 const char *p = argv[argc - 2 + i];
270                 if (!strcmp(p, "-"))
271                         /*
272                          * stdin should be spelled as "-"; if you have
273                          * path that is "-", spell it as "./-".
274                          */
275                         p = file_from_standard_input;
276                 else if (prefix)
277                         p = prefix_filename(prefix, p);
278                 paths[i] = p;
279         }
280
281         fixup_paths(paths, &replacement);
282
283         revs->diffopt.skip_stat_unmatch = 1;
284         if (!revs->diffopt.output_format)
285                 revs->diffopt.output_format = DIFF_FORMAT_PATCH;
286
287         revs->diffopt.flags.no_index = 1;
288
289         revs->diffopt.flags.relative_name = 1;
290         revs->diffopt.prefix = prefix;
291
292         revs->max_count = -2;
293         diff_setup_done(&revs->diffopt);
294
295         setup_diff_pager(&revs->diffopt);
296         revs->diffopt.flags.exit_with_status = 1;
297
298         if (queue_diff(&revs->diffopt, paths[0], paths[1]))
299                 return 1;
300         diff_set_mnemonic_prefix(&revs->diffopt, "1/", "2/");
301         diffcore_std(&revs->diffopt);
302         diff_flush(&revs->diffopt);
303
304         strbuf_release(&replacement);
305
306         /*
307          * The return code for --no-index imitates diff(1):
308          * 0 = no changes, 1 = changes, else error
309          */
310         return diff_result_code(&revs->diffopt, 0);
311 }