git/builtin/cat-file.c
Junio C Hamano 33e8fc8740 usage: do not insist that standard input must come from a file
The synopsys text and the usage string of subcommands that read list
of things from the standard input are often shown like this:

	git gostak [--distim] < <list-of-doshes>

This is problematic in a number of ways:

 * The way to use these commands is more often to feed them the
   output from another command, not feed them from a file.

 * Manual pages outside Git, commands that operate on the data read
   from the standard input, e.g "sort", "grep", "sed", etc., are not
   described with such a "< redirection-from-file" in their synopsys
   text.  Our doing so introduces inconsistency.

 * We do not insist on where the output should go, by saying

	git gostak [--distim] < <list-of-doshes> > <output>

 * As it is our convention to enclose placeholders inside <braket>,
   the redirection operator followed by a placeholder filename
   becomes very hard to read, both in the documentation and in the
   help text.

Let's clean them all up, after making sure that the documentation
clearly describes the modes that take information from the standard
input and what kind of things are expected on the input.

[jc: stole example for fmt-merge-msg from Jonathan]

Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-10-16 15:27:52 -07:00

522 lines
14 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"
#include "tree-walk.h"
#include "sha1-array.h"
struct batch_options {
int enabled;
int follow_symlinks;
int print_contents;
int buffer_output;
int all_objects;
const char *format;
};
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 batch_write(struct batch_options *opt, const void *data, int len)
{
if (opt->buffer_output) {
if (fwrite(data, 1, len, stdout) != len)
die_errno("unable to write to stdout");
} else
write_or_die(1, data, len);
}
static void print_object_or_die(struct batch_options *opt, struct expand_data *data)
{
const unsigned char *sha1 = data->sha1;
assert(data->info.typep);
if (data->type == OBJ_BLOB) {
if (opt->buffer_output)
fflush(stdout);
if (stream_blob_to_fd(1, 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));
batch_write(opt, contents, size);
free(contents);
}
}
static void batch_object_write(const char *obj_name, struct batch_options *opt,
struct expand_data *data)
{
struct strbuf buf = STRBUF_INIT;
if (sha1_object_info_extended(data->sha1, &data->info, LOOKUP_REPLACE_OBJECT) < 0) {
printf("%s missing\n", obj_name ? obj_name : sha1_to_hex(data->sha1));
fflush(stdout);
return;
}
strbuf_expand(&buf, opt->format, expand_format, data);
strbuf_addch(&buf, '\n');
batch_write(opt, buf.buf, buf.len);
strbuf_release(&buf);
if (opt->print_contents) {
print_object_or_die(opt, data);
batch_write(opt, "\n", 1);
}
}
static void batch_one_object(const char *obj_name, struct batch_options *opt,
struct expand_data *data)
{
struct object_context ctx;
int flags = opt->follow_symlinks ? GET_SHA1_FOLLOW_SYMLINKS : 0;
enum follow_symlinks_result result;
result = get_sha1_with_context(obj_name, flags, data->sha1, &ctx);
if (result != FOUND) {
switch (result) {
case MISSING_OBJECT:
printf("%s missing\n", obj_name);
break;
case DANGLING_SYMLINK:
printf("dangling %"PRIuMAX"\n%s\n",
(uintmax_t)strlen(obj_name), obj_name);
break;
case SYMLINK_LOOP:
printf("loop %"PRIuMAX"\n%s\n",
(uintmax_t)strlen(obj_name), obj_name);
break;
case NOT_DIR:
printf("notdir %"PRIuMAX"\n%s\n",
(uintmax_t)strlen(obj_name), obj_name);
break;
default:
die("BUG: unknown get_sha1_with_context result %d\n",
result);
break;
}
fflush(stdout);
return;
}
if (ctx.mode == 0) {
printf("symlink %"PRIuMAX"\n%s\n",
(uintmax_t)ctx.symlink_path.len,
ctx.symlink_path.buf);
fflush(stdout);
return;
}
batch_object_write(obj_name, opt, data);
}
struct object_cb_data {
struct batch_options *opt;
struct expand_data *expand;
};
static void batch_object_cb(const unsigned char sha1[20], void *vdata)
{
struct object_cb_data *data = vdata;
hashcpy(data->expand->sha1, sha1);
batch_object_write(NULL, data->opt, data->expand);
}
static int batch_loose_object(const unsigned char *sha1,
const char *path,
void *data)
{
sha1_array_append(data, sha1);
return 0;
}
static int batch_packed_object(const unsigned char *sha1,
struct packed_git *pack,
uint32_t pos,
void *data)
{
sha1_array_append(data, sha1);
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;
if (opt->all_objects) {
struct sha1_array sa = SHA1_ARRAY_INIT;
struct object_cb_data cb;
for_each_loose_object(batch_loose_object, &sa, 0);
for_each_packed_object(batch_packed_object, &sa, 0);
cb.opt = opt;
cb.expand = &data;
sha1_array_for_each_unique(&sa, batch_object_cb, &cb);
sha1_array_clear(&sa);
return 0;
}
/*
* 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;
}
batch_one_object(buf.buf, opt, &data);
}
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) [--follow-symlinks]"),
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 (bo->enabled) {
return 1;
}
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")),
OPT_BOOL(0, "buffer", &batch.buffer_output, N_("buffer --batch output")),
{ 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_BOOL(0, "follow-symlinks", &batch.follow_symlinks,
N_("follow in-tree symlinks (used with --batch or --batch-check)")),
OPT_BOOL(0, "batch-all-objects", &batch.all_objects,
N_("show all objects with --batch or --batch-check")),
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.follow_symlinks || batch.all_objects) && !batch.enabled) {
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);
}