git/builtin/cat-file.c
Karthik Nayak 39e4ae3880 cat-file: teach cat-file a '--allow-unknown-type' option
'git cat-file' throws an error while trying to print the type or
size of a broken/corrupt object. This is because these objects are
usually of unknown types.

Teach git cat-file a '--allow-unknown-type' option where it prints
the type or size of a broken/corrupt object without throwing
an error.

Modify '-t' and '-s' options to call sha1_object_info_extended()
directly to support the '--allow-unknown-type' option.

Add documentation for 'cat-file --allow-unknown-type'.

Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>

cat-file: add documentation for '--allow-unknown-type' option.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-05-06 13:35:48 -07:00

421 lines
11 KiB
C

/*
* GIT - The information manager from hell
*
* Copyright (C) Linus Torvalds, 2005
*/
#include "cache.h"
#include "builtin.h"
#include "parse-options.h"
#include "userdiff.h"
#include "streaming.h"
static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
int unknown_type)
{
unsigned char sha1[20];
enum object_type type;
char *buf;
unsigned long size;
struct object_context obj_context;
struct object_info oi = {NULL};
struct strbuf sb = STRBUF_INIT;
unsigned flags = LOOKUP_REPLACE_OBJECT;
if (unknown_type)
flags |= LOOKUP_UNKNOWN_OBJECT;
if (get_sha1_with_context(obj_name, 0, sha1, &obj_context))
die("Not a valid object name %s", obj_name);
buf = NULL;
switch (opt) {
case 't':
oi.typename = &sb;
if (sha1_object_info_extended(sha1, &oi, flags) < 0)
die("git cat-file: could not get object info");
if (sb.len) {
printf("%s\n", sb.buf);
strbuf_release(&sb);
return 0;
}
break;
case 's':
oi.sizep = &size;
if (sha1_object_info_extended(sha1, &oi, flags) < 0)
die("git cat-file: could not get object info");
printf("%lu\n", size);
return 0;
case 'e':
return !has_sha1_file(sha1);
case 'c':
if (!obj_context.path[0])
die("git cat-file --textconv %s: <object> must be <sha1:path>",
obj_name);
if (textconv_object(obj_context.path, obj_context.mode, sha1, 1, &buf, &size))
break;
case 'p':
type = sha1_object_info(sha1, NULL);
if (type < 0)
die("Not a valid object name %s", obj_name);
/* custom pretty-print here */
if (type == OBJ_TREE) {
const char *ls_args[3] = { NULL };
ls_args[0] = "ls-tree";
ls_args[1] = obj_name;
return cmd_ls_tree(2, ls_args, NULL);
}
if (type == OBJ_BLOB)
return stream_blob_to_fd(1, sha1, NULL, 0);
buf = read_sha1_file(sha1, &type, &size);
if (!buf)
die("Cannot read object %s", obj_name);
/* otherwise just spit out the data */
break;
case 0:
if (type_from_string(exp_type) == OBJ_BLOB) {
unsigned char blob_sha1[20];
if (sha1_object_info(sha1, NULL) == OBJ_TAG) {
char *buffer = read_sha1_file(sha1, &type, &size);
const char *target;
if (!skip_prefix(buffer, "object ", &target) ||
get_sha1_hex(target, blob_sha1))
die("%s not a valid tag", sha1_to_hex(sha1));
free(buffer);
} else
hashcpy(blob_sha1, sha1);
if (sha1_object_info(blob_sha1, NULL) == OBJ_BLOB)
return stream_blob_to_fd(1, blob_sha1, NULL, 0);
/*
* we attempted to dereference a tag to a blob
* and failed; there may be new dereference
* mechanisms this code is not aware of.
* fall-back to the usual case.
*/
}
buf = read_object_with_reference(sha1, exp_type, &size, NULL);
break;
default:
die("git cat-file: unknown option: %s", exp_type);
}
if (!buf)
die("git cat-file %s: bad file", obj_name);
write_or_die(1, buf, size);
return 0;
}
struct expand_data {
unsigned char sha1[20];
enum object_type type;
unsigned long size;
unsigned long disk_size;
const char *rest;
unsigned char delta_base_sha1[20];
/*
* If mark_query is true, we do not expand anything, but rather
* just mark the object_info with items we wish to query.
*/
int mark_query;
/*
* Whether to split the input on whitespace before feeding it to
* get_sha1; this is decided during the mark_query phase based on
* whether we have a %(rest) token in our format.
*/
int split_on_whitespace;
/*
* After a mark_query run, this object_info is set up to be
* passed to sha1_object_info_extended. It will point to the data
* elements above, so you can retrieve the response from there.
*/
struct object_info info;
};
static int is_atom(const char *atom, const char *s, int slen)
{
int alen = strlen(atom);
return alen == slen && !memcmp(atom, s, alen);
}
static void expand_atom(struct strbuf *sb, const char *atom, int len,
void *vdata)
{
struct expand_data *data = vdata;
if (is_atom("objectname", atom, len)) {
if (!data->mark_query)
strbuf_addstr(sb, sha1_to_hex(data->sha1));
} else if (is_atom("objecttype", atom, len)) {
if (data->mark_query)
data->info.typep = &data->type;
else
strbuf_addstr(sb, typename(data->type));
} else if (is_atom("objectsize", atom, len)) {
if (data->mark_query)
data->info.sizep = &data->size;
else
strbuf_addf(sb, "%lu", data->size);
} else if (is_atom("objectsize:disk", atom, len)) {
if (data->mark_query)
data->info.disk_sizep = &data->disk_size;
else
strbuf_addf(sb, "%lu", data->disk_size);
} else if (is_atom("rest", atom, len)) {
if (data->mark_query)
data->split_on_whitespace = 1;
else if (data->rest)
strbuf_addstr(sb, data->rest);
} else if (is_atom("deltabase", atom, len)) {
if (data->mark_query)
data->info.delta_base_sha1 = data->delta_base_sha1;
else
strbuf_addstr(sb, sha1_to_hex(data->delta_base_sha1));
} else
die("unknown format element: %.*s", len, atom);
}
static size_t expand_format(struct strbuf *sb, const char *start, void *data)
{
const char *end;
if (*start != '(')
return 0;
end = strchr(start + 1, ')');
if (!end)
die("format element '%s' does not end in ')'", start);
expand_atom(sb, start + 1, end - start - 1, data);
return end - start + 1;
}
static void print_object_or_die(int fd, struct expand_data *data)
{
const unsigned char *sha1 = data->sha1;
assert(data->info.typep);
if (data->type == OBJ_BLOB) {
if (stream_blob_to_fd(fd, sha1, NULL, 0) < 0)
die("unable to stream %s to stdout", sha1_to_hex(sha1));
}
else {
enum object_type type;
unsigned long size;
void *contents;
contents = read_sha1_file(sha1, &type, &size);
if (!contents)
die("object %s disappeared", sha1_to_hex(sha1));
if (type != data->type)
die("object %s changed type!?", sha1_to_hex(sha1));
if (data->info.sizep && size != data->size)
die("object %s changed size!?", sha1_to_hex(sha1));
write_or_die(fd, contents, size);
free(contents);
}
}
struct batch_options {
int enabled;
int print_contents;
const char *format;
};
static int batch_one_object(const char *obj_name, struct batch_options *opt,
struct expand_data *data)
{
struct strbuf buf = STRBUF_INIT;
if (!obj_name)
return 1;
if (get_sha1(obj_name, data->sha1)) {
printf("%s missing\n", obj_name);
fflush(stdout);
return 0;
}
if (sha1_object_info_extended(data->sha1, &data->info, LOOKUP_REPLACE_OBJECT) < 0) {
printf("%s missing\n", obj_name);
fflush(stdout);
return 0;
}
strbuf_expand(&buf, opt->format, expand_format, data);
strbuf_addch(&buf, '\n');
write_or_die(1, buf.buf, buf.len);
strbuf_release(&buf);
if (opt->print_contents) {
print_object_or_die(1, data);
write_or_die(1, "\n", 1);
}
return 0;
}
static int batch_objects(struct batch_options *opt)
{
struct strbuf buf = STRBUF_INIT;
struct expand_data data;
int save_warning;
int retval = 0;
if (!opt->format)
opt->format = "%(objectname) %(objecttype) %(objectsize)";
/*
* Expand once with our special mark_query flag, which will prime the
* object_info to be handed to sha1_object_info_extended for each
* object.
*/
memset(&data, 0, sizeof(data));
data.mark_query = 1;
strbuf_expand(&buf, opt->format, expand_format, &data);
data.mark_query = 0;
/*
* If we are printing out the object, then always fill in the type,
* since we will want to decide whether or not to stream.
*/
if (opt->print_contents)
data.info.typep = &data.type;
/*
* We are going to call get_sha1 on a potentially very large number of
* objects. In most large cases, these will be actual object sha1s. The
* cost to double-check that each one is not also a ref (just so we can
* warn) ends up dwarfing the actual cost of the object lookups
* themselves. We can work around it by just turning off the warning.
*/
save_warning = warn_on_object_refname_ambiguity;
warn_on_object_refname_ambiguity = 0;
while (strbuf_getline(&buf, stdin, '\n') != EOF) {
if (data.split_on_whitespace) {
/*
* Split at first whitespace, tying off the beginning
* of the string and saving the remainder (or NULL) in
* data.rest.
*/
char *p = strpbrk(buf.buf, " \t");
if (p) {
while (*p && strchr(" \t", *p))
*p++ = '\0';
}
data.rest = p;
}
retval = batch_one_object(buf.buf, opt, &data);
if (retval)
break;
}
strbuf_release(&buf);
warn_on_object_refname_ambiguity = save_warning;
return retval;
}
static const char * const cat_file_usage[] = {
N_("git cat-file (-t [--allow-unknown-type]|-s [--allow-unknown-type]|-e|-p|<type>|--textconv) <object>"),
N_("git cat-file (--batch | --batch-check) < <list-of-objects>"),
NULL
};
static int git_cat_file_config(const char *var, const char *value, void *cb)
{
if (userdiff_config(var, value) < 0)
return -1;
return git_default_config(var, value, cb);
}
static int batch_option_callback(const struct option *opt,
const char *arg,
int unset)
{
struct batch_options *bo = opt->value;
if (unset) {
memset(bo, 0, sizeof(*bo));
return 0;
}
bo->enabled = 1;
bo->print_contents = !strcmp(opt->long_name, "batch");
bo->format = arg;
return 0;
}
int cmd_cat_file(int argc, const char **argv, const char *prefix)
{
int opt = 0;
const char *exp_type = NULL, *obj_name = NULL;
struct batch_options batch = {0};
int unknown_type = 0;
const struct option options[] = {
OPT_GROUP(N_("<type> can be one of: blob, tree, commit, tag")),
OPT_CMDMODE('t', NULL, &opt, N_("show object type"), 't'),
OPT_CMDMODE('s', NULL, &opt, N_("show object size"), 's'),
OPT_CMDMODE('e', NULL, &opt,
N_("exit with zero when there's no error"), 'e'),
OPT_CMDMODE('p', NULL, &opt, N_("pretty-print object's content"), 'p'),
OPT_CMDMODE(0, "textconv", &opt,
N_("for blob objects, run textconv on object's content"), 'c'),
OPT_BOOL( 0, "allow-unknown-type", &unknown_type,
N_("allow -s and -t to work with broken/corrupt objects")),
{ OPTION_CALLBACK, 0, "batch", &batch, "format",
N_("show info and content of objects fed from the standard input"),
PARSE_OPT_OPTARG, batch_option_callback },
{ OPTION_CALLBACK, 0, "batch-check", &batch, "format",
N_("show info about objects fed from the standard input"),
PARSE_OPT_OPTARG, batch_option_callback },
OPT_END()
};
git_config(git_cat_file_config, NULL);
argc = parse_options(argc, argv, prefix, options, cat_file_usage, 0);
if (opt) {
if (argc == 1)
obj_name = argv[0];
else
usage_with_options(cat_file_usage, options);
}
if (!opt && !batch.enabled) {
if (argc == 2) {
exp_type = argv[0];
obj_name = argv[1];
} else
usage_with_options(cat_file_usage, options);
}
if (batch.enabled && (opt || argc)) {
usage_with_options(cat_file_usage, options);
}
if (batch.enabled)
return batch_objects(&batch);
if (unknown_type && opt != 't' && opt != 's')
die("git cat-file --allow-unknown-type: use with -s or -t");
return cat_one_file(opt, exp_type, obj_name, unknown_type);
}