Merge branch 'as/docfix-reflog-expire-unreachable' into maint
[git] / builtin / cat-file.c
1 /*
2  * GIT - The information manager from hell
3  *
4  * Copyright (C) Linus Torvalds, 2005
5  */
6 #include "cache.h"
7 #include "builtin.h"
8 #include "parse-options.h"
9 #include "userdiff.h"
10 #include "streaming.h"
11 #include "tree-walk.h"
12
13 static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
14                         int unknown_type)
15 {
16         unsigned char sha1[20];
17         enum object_type type;
18         char *buf;
19         unsigned long size;
20         struct object_context obj_context;
21         struct object_info oi = {NULL};
22         struct strbuf sb = STRBUF_INIT;
23         unsigned flags = LOOKUP_REPLACE_OBJECT;
24
25         if (unknown_type)
26                 flags |= LOOKUP_UNKNOWN_OBJECT;
27
28         if (get_sha1_with_context(obj_name, 0, sha1, &obj_context))
29                 die("Not a valid object name %s", obj_name);
30
31         buf = NULL;
32         switch (opt) {
33         case 't':
34                 oi.typename = &sb;
35                 if (sha1_object_info_extended(sha1, &oi, flags) < 0)
36                         die("git cat-file: could not get object info");
37                 if (sb.len) {
38                         printf("%s\n", sb.buf);
39                         strbuf_release(&sb);
40                         return 0;
41                 }
42                 break;
43
44         case 's':
45                 oi.sizep = &size;
46                 if (sha1_object_info_extended(sha1, &oi, flags) < 0)
47                         die("git cat-file: could not get object info");
48                 printf("%lu\n", size);
49                 return 0;
50
51         case 'e':
52                 return !has_sha1_file(sha1);
53
54         case 'c':
55                 if (!obj_context.path[0])
56                         die("git cat-file --textconv %s: <object> must be <sha1:path>",
57                             obj_name);
58
59                 if (textconv_object(obj_context.path, obj_context.mode, sha1, 1, &buf, &size))
60                         break;
61
62         case 'p':
63                 type = sha1_object_info(sha1, NULL);
64                 if (type < 0)
65                         die("Not a valid object name %s", obj_name);
66
67                 /* custom pretty-print here */
68                 if (type == OBJ_TREE) {
69                         const char *ls_args[3] = { NULL };
70                         ls_args[0] =  "ls-tree";
71                         ls_args[1] =  obj_name;
72                         return cmd_ls_tree(2, ls_args, NULL);
73                 }
74
75                 if (type == OBJ_BLOB)
76                         return stream_blob_to_fd(1, sha1, NULL, 0);
77                 buf = read_sha1_file(sha1, &type, &size);
78                 if (!buf)
79                         die("Cannot read object %s", obj_name);
80
81                 /* otherwise just spit out the data */
82                 break;
83
84         case 0:
85                 if (type_from_string(exp_type) == OBJ_BLOB) {
86                         unsigned char blob_sha1[20];
87                         if (sha1_object_info(sha1, NULL) == OBJ_TAG) {
88                                 char *buffer = read_sha1_file(sha1, &type, &size);
89                                 const char *target;
90                                 if (!skip_prefix(buffer, "object ", &target) ||
91                                     get_sha1_hex(target, blob_sha1))
92                                         die("%s not a valid tag", sha1_to_hex(sha1));
93                                 free(buffer);
94                         } else
95                                 hashcpy(blob_sha1, sha1);
96
97                         if (sha1_object_info(blob_sha1, NULL) == OBJ_BLOB)
98                                 return stream_blob_to_fd(1, blob_sha1, NULL, 0);
99                         /*
100                          * we attempted to dereference a tag to a blob
101                          * and failed; there may be new dereference
102                          * mechanisms this code is not aware of.
103                          * fall-back to the usual case.
104                          */
105                 }
106                 buf = read_object_with_reference(sha1, exp_type, &size, NULL);
107                 break;
108
109         default:
110                 die("git cat-file: unknown option: %s", exp_type);
111         }
112
113         if (!buf)
114                 die("git cat-file %s: bad file", obj_name);
115
116         write_or_die(1, buf, size);
117         return 0;
118 }
119
120 struct expand_data {
121         unsigned char sha1[20];
122         enum object_type type;
123         unsigned long size;
124         unsigned long disk_size;
125         const char *rest;
126         unsigned char delta_base_sha1[20];
127
128         /*
129          * If mark_query is true, we do not expand anything, but rather
130          * just mark the object_info with items we wish to query.
131          */
132         int mark_query;
133
134         /*
135          * Whether to split the input on whitespace before feeding it to
136          * get_sha1; this is decided during the mark_query phase based on
137          * whether we have a %(rest) token in our format.
138          */
139         int split_on_whitespace;
140
141         /*
142          * After a mark_query run, this object_info is set up to be
143          * passed to sha1_object_info_extended. It will point to the data
144          * elements above, so you can retrieve the response from there.
145          */
146         struct object_info info;
147 };
148
149 static int is_atom(const char *atom, const char *s, int slen)
150 {
151         int alen = strlen(atom);
152         return alen == slen && !memcmp(atom, s, alen);
153 }
154
155 static void expand_atom(struct strbuf *sb, const char *atom, int len,
156                         void *vdata)
157 {
158         struct expand_data *data = vdata;
159
160         if (is_atom("objectname", atom, len)) {
161                 if (!data->mark_query)
162                         strbuf_addstr(sb, sha1_to_hex(data->sha1));
163         } else if (is_atom("objecttype", atom, len)) {
164                 if (data->mark_query)
165                         data->info.typep = &data->type;
166                 else
167                         strbuf_addstr(sb, typename(data->type));
168         } else if (is_atom("objectsize", atom, len)) {
169                 if (data->mark_query)
170                         data->info.sizep = &data->size;
171                 else
172                         strbuf_addf(sb, "%lu", data->size);
173         } else if (is_atom("objectsize:disk", atom, len)) {
174                 if (data->mark_query)
175                         data->info.disk_sizep = &data->disk_size;
176                 else
177                         strbuf_addf(sb, "%lu", data->disk_size);
178         } else if (is_atom("rest", atom, len)) {
179                 if (data->mark_query)
180                         data->split_on_whitespace = 1;
181                 else if (data->rest)
182                         strbuf_addstr(sb, data->rest);
183         } else if (is_atom("deltabase", atom, len)) {
184                 if (data->mark_query)
185                         data->info.delta_base_sha1 = data->delta_base_sha1;
186                 else
187                         strbuf_addstr(sb, sha1_to_hex(data->delta_base_sha1));
188         } else
189                 die("unknown format element: %.*s", len, atom);
190 }
191
192 static size_t expand_format(struct strbuf *sb, const char *start, void *data)
193 {
194         const char *end;
195
196         if (*start != '(')
197                 return 0;
198         end = strchr(start + 1, ')');
199         if (!end)
200                 die("format element '%s' does not end in ')'", start);
201
202         expand_atom(sb, start + 1, end - start - 1, data);
203
204         return end - start + 1;
205 }
206
207 static void print_object_or_die(int fd, struct expand_data *data)
208 {
209         const unsigned char *sha1 = data->sha1;
210
211         assert(data->info.typep);
212
213         if (data->type == OBJ_BLOB) {
214                 if (stream_blob_to_fd(fd, sha1, NULL, 0) < 0)
215                         die("unable to stream %s to stdout", sha1_to_hex(sha1));
216         }
217         else {
218                 enum object_type type;
219                 unsigned long size;
220                 void *contents;
221
222                 contents = read_sha1_file(sha1, &type, &size);
223                 if (!contents)
224                         die("object %s disappeared", sha1_to_hex(sha1));
225                 if (type != data->type)
226                         die("object %s changed type!?", sha1_to_hex(sha1));
227                 if (data->info.sizep && size != data->size)
228                         die("object %s changed size!?", sha1_to_hex(sha1));
229
230                 write_or_die(fd, contents, size);
231                 free(contents);
232         }
233 }
234
235 struct batch_options {
236         int enabled;
237         int follow_symlinks;
238         int print_contents;
239         const char *format;
240 };
241
242 static int batch_one_object(const char *obj_name, struct batch_options *opt,
243                             struct expand_data *data)
244 {
245         struct strbuf buf = STRBUF_INIT;
246         struct object_context ctx;
247         int flags = opt->follow_symlinks ? GET_SHA1_FOLLOW_SYMLINKS : 0;
248         enum follow_symlinks_result result;
249
250         if (!obj_name)
251            return 1;
252
253         result = get_sha1_with_context(obj_name, flags, data->sha1, &ctx);
254         if (result != FOUND) {
255                 switch (result) {
256                 case MISSING_OBJECT:
257                         printf("%s missing\n", obj_name);
258                         break;
259                 case DANGLING_SYMLINK:
260                         printf("dangling %"PRIuMAX"\n%s\n",
261                                (uintmax_t)strlen(obj_name), obj_name);
262                         break;
263                 case SYMLINK_LOOP:
264                         printf("loop %"PRIuMAX"\n%s\n",
265                                (uintmax_t)strlen(obj_name), obj_name);
266                         break;
267                 case NOT_DIR:
268                         printf("notdir %"PRIuMAX"\n%s\n",
269                                (uintmax_t)strlen(obj_name), obj_name);
270                         break;
271                 default:
272                         die("BUG: unknown get_sha1_with_context result %d\n",
273                                result);
274                         break;
275                 }
276                 fflush(stdout);
277                 return 0;
278         }
279
280         if (ctx.mode == 0) {
281                 printf("symlink %"PRIuMAX"\n%s\n",
282                        (uintmax_t)ctx.symlink_path.len,
283                        ctx.symlink_path.buf);
284                 fflush(stdout);
285                 return 0;
286         }
287
288         if (sha1_object_info_extended(data->sha1, &data->info, LOOKUP_REPLACE_OBJECT) < 0) {
289                 printf("%s missing\n", obj_name);
290                 fflush(stdout);
291                 return 0;
292         }
293
294         strbuf_expand(&buf, opt->format, expand_format, data);
295         strbuf_addch(&buf, '\n');
296         write_or_die(1, buf.buf, buf.len);
297         strbuf_release(&buf);
298
299         if (opt->print_contents) {
300                 print_object_or_die(1, data);
301                 write_or_die(1, "\n", 1);
302         }
303         return 0;
304 }
305
306 static int batch_objects(struct batch_options *opt)
307 {
308         struct strbuf buf = STRBUF_INIT;
309         struct expand_data data;
310         int save_warning;
311         int retval = 0;
312
313         if (!opt->format)
314                 opt->format = "%(objectname) %(objecttype) %(objectsize)";
315
316         /*
317          * Expand once with our special mark_query flag, which will prime the
318          * object_info to be handed to sha1_object_info_extended for each
319          * object.
320          */
321         memset(&data, 0, sizeof(data));
322         data.mark_query = 1;
323         strbuf_expand(&buf, opt->format, expand_format, &data);
324         data.mark_query = 0;
325
326         /*
327          * If we are printing out the object, then always fill in the type,
328          * since we will want to decide whether or not to stream.
329          */
330         if (opt->print_contents)
331                 data.info.typep = &data.type;
332
333         /*
334          * We are going to call get_sha1 on a potentially very large number of
335          * objects. In most large cases, these will be actual object sha1s. The
336          * cost to double-check that each one is not also a ref (just so we can
337          * warn) ends up dwarfing the actual cost of the object lookups
338          * themselves. We can work around it by just turning off the warning.
339          */
340         save_warning = warn_on_object_refname_ambiguity;
341         warn_on_object_refname_ambiguity = 0;
342
343         while (strbuf_getline(&buf, stdin, '\n') != EOF) {
344                 if (data.split_on_whitespace) {
345                         /*
346                          * Split at first whitespace, tying off the beginning
347                          * of the string and saving the remainder (or NULL) in
348                          * data.rest.
349                          */
350                         char *p = strpbrk(buf.buf, " \t");
351                         if (p) {
352                                 while (*p && strchr(" \t", *p))
353                                         *p++ = '\0';
354                         }
355                         data.rest = p;
356                 }
357
358                 retval = batch_one_object(buf.buf, opt, &data);
359                 if (retval)
360                         break;
361         }
362
363         strbuf_release(&buf);
364         warn_on_object_refname_ambiguity = save_warning;
365         return retval;
366 }
367
368 static const char * const cat_file_usage[] = {
369         N_("git cat-file (-t [--allow-unknown-type]|-s [--allow-unknown-type]|-e|-p|<type>|--textconv) <object>"),
370         N_("git cat-file (--batch | --batch-check) [--follow-symlinks] < <list-of-objects>"),
371         NULL
372 };
373
374 static int git_cat_file_config(const char *var, const char *value, void *cb)
375 {
376         if (userdiff_config(var, value) < 0)
377                 return -1;
378
379         return git_default_config(var, value, cb);
380 }
381
382 static int batch_option_callback(const struct option *opt,
383                                  const char *arg,
384                                  int unset)
385 {
386         struct batch_options *bo = opt->value;
387
388         if (bo->enabled) {
389                 return 1;
390         }
391
392         bo->enabled = 1;
393         bo->print_contents = !strcmp(opt->long_name, "batch");
394         bo->format = arg;
395
396         return 0;
397 }
398
399 int cmd_cat_file(int argc, const char **argv, const char *prefix)
400 {
401         int opt = 0;
402         const char *exp_type = NULL, *obj_name = NULL;
403         struct batch_options batch = {0};
404         int unknown_type = 0;
405
406         const struct option options[] = {
407                 OPT_GROUP(N_("<type> can be one of: blob, tree, commit, tag")),
408                 OPT_CMDMODE('t', NULL, &opt, N_("show object type"), 't'),
409                 OPT_CMDMODE('s', NULL, &opt, N_("show object size"), 's'),
410                 OPT_CMDMODE('e', NULL, &opt,
411                             N_("exit with zero when there's no error"), 'e'),
412                 OPT_CMDMODE('p', NULL, &opt, N_("pretty-print object's content"), 'p'),
413                 OPT_CMDMODE(0, "textconv", &opt,
414                             N_("for blob objects, run textconv on object's content"), 'c'),
415                 OPT_BOOL( 0, "allow-unknown-type", &unknown_type,
416                           N_("allow -s and -t to work with broken/corrupt objects")),
417                 { OPTION_CALLBACK, 0, "batch", &batch, "format",
418                         N_("show info and content of objects fed from the standard input"),
419                         PARSE_OPT_OPTARG, batch_option_callback },
420                 { OPTION_CALLBACK, 0, "batch-check", &batch, "format",
421                         N_("show info about objects fed from the standard input"),
422                         PARSE_OPT_OPTARG, batch_option_callback },
423                 OPT_BOOL(0, "follow-symlinks", &batch.follow_symlinks,
424                          N_("follow in-tree symlinks (used with --batch or --batch-check)")),
425                 OPT_END()
426         };
427
428         git_config(git_cat_file_config, NULL);
429
430         argc = parse_options(argc, argv, prefix, options, cat_file_usage, 0);
431
432         if (opt) {
433                 if (argc == 1)
434                         obj_name = argv[0];
435                 else
436                         usage_with_options(cat_file_usage, options);
437         }
438         if (!opt && !batch.enabled) {
439                 if (argc == 2) {
440                         exp_type = argv[0];
441                         obj_name = argv[1];
442                 } else
443                         usage_with_options(cat_file_usage, options);
444         }
445         if (batch.enabled && (opt || argc)) {
446                 usage_with_options(cat_file_usage, options);
447         }
448
449         if (batch.follow_symlinks && !batch.enabled) {
450                 usage_with_options(cat_file_usage, options);
451         }
452
453         if (batch.enabled)
454                 return batch_objects(&batch);
455
456         if (unknown_type && opt != 't' && opt != 's')
457                 die("git cat-file --allow-unknown-type: use with -s or -t");
458         return cat_one_file(opt, exp_type, obj_name, unknown_type);
459 }