git/builtin/cat-file.c
Jeff King 6554dfa97a cat-file: handle --batch format with missing type/size
Commit 98e2092 taught cat-file to stream blobs with --batch,
which requires that we look up the object type before
loading it into memory.  As a result, we now print the
object header from information in sha1_object_info, and the
actual contents from the read_sha1_file. We double-check
that the information we printed in the header matches the
content we are about to show.

Later, commit 93d2a60 allowed custom header lines for
--batch, and commit 5b08640 made type lookups optional. As a
result, specifying a header line without the type or size
means that we will not look up those items at all.

This causes our double-checking to erroneously die with an
error; we think the type or size has changed, when in fact
it was simply left at "0".

For the size, we can fix this by only doing the consistency
double-check when we have retrieved the size via
sha1_object_info. In the case that we have not retrieved the
value, that means we also did not print it, so there is
nothing for us to check that we are consistent with.

We could do the same for the type. However, besides our
consistency check, we also care about the type in deciding
whether to stream or not. So instead of handling the case
where we do not know the type, this patch instead makes sure
that we always trigger a type lookup when we are printing,
so that even a format without the type will stream as we
would in the normal case.

Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-12 11:31:25 -08:00

405 lines
9.9 KiB
C

/*
* GIT - The information manager from hell
*
* Copyright (C) Linus Torvalds, 2005
*/
#include "cache.h"
#include "exec_cmd.h"
#include "tag.h"
#include "tree.h"
#include "builtin.h"
#include "parse-options.h"
#include "diff.h"
#include "userdiff.h"
#include "streaming.h"
static int cat_one_file(int opt, const char *exp_type, const char *obj_name)
{
unsigned char sha1[20];
enum object_type type;
char *buf;
unsigned long size;
struct object_context obj_context;
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':
type = sha1_object_info(sha1, NULL);
if (type > 0) {
printf("%s\n", typename(type));
return 0;
}
break;
case 's':
type = sha1_object_info(sha1, &size);
if (type > 0) {
printf("%lu\n", size);
return 0;
}
break;
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) {
enum object_type type;
unsigned long size;
char *buffer = read_sha1_file(sha1, &type, &size);
if (memcmp(buffer, "object ", 7) ||
get_sha1_hex(buffer + 7, 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;
/*
* 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
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) < 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;
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.
*/
warn_on_object_refname_ambiguity = 0;
while (strbuf_getline(&buf, stdin, '\n') != EOF) {
int error;
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;
}
error = batch_one_object(buf.buf, opt, &data);
if (error)
return error;
}
return 0;
}
static const char * const cat_file_usage[] = {
N_("git cat-file (-t|-s|-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};
const struct option options[] = {
OPT_GROUP(N_("<type> can be one of: blob, tree, commit, tag")),
OPT_SET_INT('t', NULL, &opt, N_("show object type"), 't'),
OPT_SET_INT('s', NULL, &opt, N_("show object size"), 's'),
OPT_SET_INT('e', NULL, &opt,
N_("exit with zero when there's no error"), 'e'),
OPT_SET_INT('p', NULL, &opt, N_("pretty-print object's content"), 'p'),
OPT_SET_INT(0, "textconv", &opt,
N_("for blob objects, run textconv on object's content"), 'c'),
{ 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);
if (argc != 3 && argc != 2)
usage_with_options(cat_file_usage, options);
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);
return cat_one_file(opt, exp_type, obj_name);
}