Merge branch 'mh/write-refs-sooner-2.4'
[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
12 static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
13                         int unknown_type)
14 {
15         unsigned char sha1[20];
16         enum object_type type;
17         char *buf;
18         unsigned long size;
19         struct object_context obj_context;
20         struct object_info oi = {NULL};
21         struct strbuf sb = STRBUF_INIT;
22         unsigned flags = LOOKUP_REPLACE_OBJECT;
23
24         if (unknown_type)
25                 flags |= LOOKUP_UNKNOWN_OBJECT;
26
27         if (get_sha1_with_context(obj_name, 0, sha1, &obj_context))
28                 die("Not a valid object name %s", obj_name);
29
30         buf = NULL;
31         switch (opt) {
32         case 't':
33                 oi.typename = &sb;
34                 if (sha1_object_info_extended(sha1, &oi, flags) < 0)
35                         die("git cat-file: could not get object info");
36                 if (sb.len) {
37                         printf("%s\n", sb.buf);
38                         strbuf_release(&sb);
39                         return 0;
40                 }
41                 break;
42
43         case 's':
44                 oi.sizep = &size;
45                 if (sha1_object_info_extended(sha1, &oi, flags) < 0)
46                         die("git cat-file: could not get object info");
47                 printf("%lu\n", size);
48                 return 0;
49
50         case 'e':
51                 return !has_sha1_file(sha1);
52
53         case 'c':
54                 if (!obj_context.path[0])
55                         die("git cat-file --textconv %s: <object> must be <sha1:path>",
56                             obj_name);
57
58                 if (textconv_object(obj_context.path, obj_context.mode, sha1, 1, &buf, &size))
59                         break;
60
61         case 'p':
62                 type = sha1_object_info(sha1, NULL);
63                 if (type < 0)
64                         die("Not a valid object name %s", obj_name);
65
66                 /* custom pretty-print here */
67                 if (type == OBJ_TREE) {
68                         const char *ls_args[3] = { NULL };
69                         ls_args[0] =  "ls-tree";
70                         ls_args[1] =  obj_name;
71                         return cmd_ls_tree(2, ls_args, NULL);
72                 }
73
74                 if (type == OBJ_BLOB)
75                         return stream_blob_to_fd(1, sha1, NULL, 0);
76                 buf = read_sha1_file(sha1, &type, &size);
77                 if (!buf)
78                         die("Cannot read object %s", obj_name);
79
80                 /* otherwise just spit out the data */
81                 break;
82
83         case 0:
84                 if (type_from_string(exp_type) == OBJ_BLOB) {
85                         unsigned char blob_sha1[20];
86                         if (sha1_object_info(sha1, NULL) == OBJ_TAG) {
87                                 char *buffer = read_sha1_file(sha1, &type, &size);
88                                 const char *target;
89                                 if (!skip_prefix(buffer, "object ", &target) ||
90                                     get_sha1_hex(target, blob_sha1))
91                                         die("%s not a valid tag", sha1_to_hex(sha1));
92                                 free(buffer);
93                         } else
94                                 hashcpy(blob_sha1, sha1);
95
96                         if (sha1_object_info(blob_sha1, NULL) == OBJ_BLOB)
97                                 return stream_blob_to_fd(1, blob_sha1, NULL, 0);
98                         /*
99                          * we attempted to dereference a tag to a blob
100                          * and failed; there may be new dereference
101                          * mechanisms this code is not aware of.
102                          * fall-back to the usual case.
103                          */
104                 }
105                 buf = read_object_with_reference(sha1, exp_type, &size, NULL);
106                 break;
107
108         default:
109                 die("git cat-file: unknown option: %s", exp_type);
110         }
111
112         if (!buf)
113                 die("git cat-file %s: bad file", obj_name);
114
115         write_or_die(1, buf, size);
116         return 0;
117 }
118
119 struct expand_data {
120         unsigned char sha1[20];
121         enum object_type type;
122         unsigned long size;
123         unsigned long disk_size;
124         const char *rest;
125         unsigned char delta_base_sha1[20];
126
127         /*
128          * If mark_query is true, we do not expand anything, but rather
129          * just mark the object_info with items we wish to query.
130          */
131         int mark_query;
132
133         /*
134          * Whether to split the input on whitespace before feeding it to
135          * get_sha1; this is decided during the mark_query phase based on
136          * whether we have a %(rest) token in our format.
137          */
138         int split_on_whitespace;
139
140         /*
141          * After a mark_query run, this object_info is set up to be
142          * passed to sha1_object_info_extended. It will point to the data
143          * elements above, so you can retrieve the response from there.
144          */
145         struct object_info info;
146 };
147
148 static int is_atom(const char *atom, const char *s, int slen)
149 {
150         int alen = strlen(atom);
151         return alen == slen && !memcmp(atom, s, alen);
152 }
153
154 static void expand_atom(struct strbuf *sb, const char *atom, int len,
155                         void *vdata)
156 {
157         struct expand_data *data = vdata;
158
159         if (is_atom("objectname", atom, len)) {
160                 if (!data->mark_query)
161                         strbuf_addstr(sb, sha1_to_hex(data->sha1));
162         } else if (is_atom("objecttype", atom, len)) {
163                 if (data->mark_query)
164                         data->info.typep = &data->type;
165                 else
166                         strbuf_addstr(sb, typename(data->type));
167         } else if (is_atom("objectsize", atom, len)) {
168                 if (data->mark_query)
169                         data->info.sizep = &data->size;
170                 else
171                         strbuf_addf(sb, "%lu", data->size);
172         } else if (is_atom("objectsize:disk", atom, len)) {
173                 if (data->mark_query)
174                         data->info.disk_sizep = &data->disk_size;
175                 else
176                         strbuf_addf(sb, "%lu", data->disk_size);
177         } else if (is_atom("rest", atom, len)) {
178                 if (data->mark_query)
179                         data->split_on_whitespace = 1;
180                 else if (data->rest)
181                         strbuf_addstr(sb, data->rest);
182         } else if (is_atom("deltabase", atom, len)) {
183                 if (data->mark_query)
184                         data->info.delta_base_sha1 = data->delta_base_sha1;
185                 else
186                         strbuf_addstr(sb, sha1_to_hex(data->delta_base_sha1));
187         } else
188                 die("unknown format element: %.*s", len, atom);
189 }
190
191 static size_t expand_format(struct strbuf *sb, const char *start, void *data)
192 {
193         const char *end;
194
195         if (*start != '(')
196                 return 0;
197         end = strchr(start + 1, ')');
198         if (!end)
199                 die("format element '%s' does not end in ')'", start);
200
201         expand_atom(sb, start + 1, end - start - 1, data);
202
203         return end - start + 1;
204 }
205
206 static void print_object_or_die(int fd, struct expand_data *data)
207 {
208         const unsigned char *sha1 = data->sha1;
209
210         assert(data->info.typep);
211
212         if (data->type == OBJ_BLOB) {
213                 if (stream_blob_to_fd(fd, sha1, NULL, 0) < 0)
214                         die("unable to stream %s to stdout", sha1_to_hex(sha1));
215         }
216         else {
217                 enum object_type type;
218                 unsigned long size;
219                 void *contents;
220
221                 contents = read_sha1_file(sha1, &type, &size);
222                 if (!contents)
223                         die("object %s disappeared", sha1_to_hex(sha1));
224                 if (type != data->type)
225                         die("object %s changed type!?", sha1_to_hex(sha1));
226                 if (data->info.sizep && size != data->size)
227                         die("object %s changed size!?", sha1_to_hex(sha1));
228
229                 write_or_die(fd, contents, size);
230                 free(contents);
231         }
232 }
233
234 struct batch_options {
235         int enabled;
236         int print_contents;
237         const char *format;
238 };
239
240 static int batch_one_object(const char *obj_name, struct batch_options *opt,
241                             struct expand_data *data)
242 {
243         struct strbuf buf = STRBUF_INIT;
244
245         if (!obj_name)
246            return 1;
247
248         if (get_sha1(obj_name, data->sha1)) {
249                 printf("%s missing\n", obj_name);
250                 fflush(stdout);
251                 return 0;
252         }
253
254         if (sha1_object_info_extended(data->sha1, &data->info, LOOKUP_REPLACE_OBJECT) < 0) {
255                 printf("%s missing\n", obj_name);
256                 fflush(stdout);
257                 return 0;
258         }
259
260         strbuf_expand(&buf, opt->format, expand_format, data);
261         strbuf_addch(&buf, '\n');
262         write_or_die(1, buf.buf, buf.len);
263         strbuf_release(&buf);
264
265         if (opt->print_contents) {
266                 print_object_or_die(1, data);
267                 write_or_die(1, "\n", 1);
268         }
269         return 0;
270 }
271
272 static int batch_objects(struct batch_options *opt)
273 {
274         struct strbuf buf = STRBUF_INIT;
275         struct expand_data data;
276         int save_warning;
277         int retval = 0;
278
279         if (!opt->format)
280                 opt->format = "%(objectname) %(objecttype) %(objectsize)";
281
282         /*
283          * Expand once with our special mark_query flag, which will prime the
284          * object_info to be handed to sha1_object_info_extended for each
285          * object.
286          */
287         memset(&data, 0, sizeof(data));
288         data.mark_query = 1;
289         strbuf_expand(&buf, opt->format, expand_format, &data);
290         data.mark_query = 0;
291
292         /*
293          * If we are printing out the object, then always fill in the type,
294          * since we will want to decide whether or not to stream.
295          */
296         if (opt->print_contents)
297                 data.info.typep = &data.type;
298
299         /*
300          * We are going to call get_sha1 on a potentially very large number of
301          * objects. In most large cases, these will be actual object sha1s. The
302          * cost to double-check that each one is not also a ref (just so we can
303          * warn) ends up dwarfing the actual cost of the object lookups
304          * themselves. We can work around it by just turning off the warning.
305          */
306         save_warning = warn_on_object_refname_ambiguity;
307         warn_on_object_refname_ambiguity = 0;
308
309         while (strbuf_getline(&buf, stdin, '\n') != EOF) {
310                 if (data.split_on_whitespace) {
311                         /*
312                          * Split at first whitespace, tying off the beginning
313                          * of the string and saving the remainder (or NULL) in
314                          * data.rest.
315                          */
316                         char *p = strpbrk(buf.buf, " \t");
317                         if (p) {
318                                 while (*p && strchr(" \t", *p))
319                                         *p++ = '\0';
320                         }
321                         data.rest = p;
322                 }
323
324                 retval = batch_one_object(buf.buf, opt, &data);
325                 if (retval)
326                         break;
327         }
328
329         strbuf_release(&buf);
330         warn_on_object_refname_ambiguity = save_warning;
331         return retval;
332 }
333
334 static const char * const cat_file_usage[] = {
335         N_("git cat-file (-t [--allow-unknown-type]|-s [--allow-unknown-type]|-e|-p|<type>|--textconv) <object>"),
336         N_("git cat-file (--batch | --batch-check) < <list-of-objects>"),
337         NULL
338 };
339
340 static int git_cat_file_config(const char *var, const char *value, void *cb)
341 {
342         if (userdiff_config(var, value) < 0)
343                 return -1;
344
345         return git_default_config(var, value, cb);
346 }
347
348 static int batch_option_callback(const struct option *opt,
349                                  const char *arg,
350                                  int unset)
351 {
352         struct batch_options *bo = opt->value;
353
354         if (unset) {
355                 memset(bo, 0, sizeof(*bo));
356                 return 0;
357         }
358
359         bo->enabled = 1;
360         bo->print_contents = !strcmp(opt->long_name, "batch");
361         bo->format = arg;
362
363         return 0;
364 }
365
366 int cmd_cat_file(int argc, const char **argv, const char *prefix)
367 {
368         int opt = 0;
369         const char *exp_type = NULL, *obj_name = NULL;
370         struct batch_options batch = {0};
371         int unknown_type = 0;
372
373         const struct option options[] = {
374                 OPT_GROUP(N_("<type> can be one of: blob, tree, commit, tag")),
375                 OPT_CMDMODE('t', NULL, &opt, N_("show object type"), 't'),
376                 OPT_CMDMODE('s', NULL, &opt, N_("show object size"), 's'),
377                 OPT_CMDMODE('e', NULL, &opt,
378                             N_("exit with zero when there's no error"), 'e'),
379                 OPT_CMDMODE('p', NULL, &opt, N_("pretty-print object's content"), 'p'),
380                 OPT_CMDMODE(0, "textconv", &opt,
381                             N_("for blob objects, run textconv on object's content"), 'c'),
382                 OPT_BOOL( 0, "allow-unknown-type", &unknown_type,
383                           N_("allow -s and -t to work with broken/corrupt objects")),
384                 { OPTION_CALLBACK, 0, "batch", &batch, "format",
385                         N_("show info and content of objects fed from the standard input"),
386                         PARSE_OPT_OPTARG, batch_option_callback },
387                 { OPTION_CALLBACK, 0, "batch-check", &batch, "format",
388                         N_("show info about objects fed from the standard input"),
389                         PARSE_OPT_OPTARG, batch_option_callback },
390                 OPT_END()
391         };
392
393         git_config(git_cat_file_config, NULL);
394
395         argc = parse_options(argc, argv, prefix, options, cat_file_usage, 0);
396
397         if (opt) {
398                 if (argc == 1)
399                         obj_name = argv[0];
400                 else
401                         usage_with_options(cat_file_usage, options);
402         }
403         if (!opt && !batch.enabled) {
404                 if (argc == 2) {
405                         exp_type = argv[0];
406                         obj_name = argv[1];
407                 } else
408                         usage_with_options(cat_file_usage, options);
409         }
410         if (batch.enabled && (opt || argc)) {
411                 usage_with_options(cat_file_usage, options);
412         }
413
414         if (batch.enabled)
415                 return batch_objects(&batch);
416
417         if (unknown_type && opt != 't' && opt != 's')
418                 die("git cat-file --allow-unknown-type: use with -s or -t");
419         return cat_one_file(opt, exp_type, obj_name, unknown_type);
420 }