git/builtin-fast-export.c
Geoffrey Irving 79559f27be git fast-export: add --no-data option
When using git fast-export and git fast-import to rewrite the history
of a repository with large binary files, almost all of the time is
spent dealing with blobs.  This is extremely inefficient if all we want
to do is rewrite the commits and tree structure.  --no-data skips the
output of blobs and writes SHA-1s instead of marks, which provides a
massive speedup.

Signed-off-by: Geoffrey Irving <irving@naml.us>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-07-31 07:48:09 -07:00

634 lines
16 KiB
C

/*
* "git fast-export" builtin command
*
* Copyright (C) 2007 Johannes E. Schindelin
*/
#include "builtin.h"
#include "cache.h"
#include "commit.h"
#include "object.h"
#include "tag.h"
#include "diff.h"
#include "diffcore.h"
#include "log-tree.h"
#include "revision.h"
#include "decorate.h"
#include "string-list.h"
#include "utf8.h"
#include "parse-options.h"
static const char *fast_export_usage[] = {
"git fast-export [rev-list-opts]",
NULL
};
static int progress;
static enum { ABORT, VERBATIM, WARN, STRIP } signed_tag_mode = ABORT;
static enum { ERROR, DROP, REWRITE } tag_of_filtered_mode = ABORT;
static int fake_missing_tagger;
static int no_data;
static int parse_opt_signed_tag_mode(const struct option *opt,
const char *arg, int unset)
{
if (unset || !strcmp(arg, "abort"))
signed_tag_mode = ABORT;
else if (!strcmp(arg, "verbatim") || !strcmp(arg, "ignore"))
signed_tag_mode = VERBATIM;
else if (!strcmp(arg, "warn"))
signed_tag_mode = WARN;
else if (!strcmp(arg, "strip"))
signed_tag_mode = STRIP;
else
return error("Unknown signed-tag mode: %s", arg);
return 0;
}
static int parse_opt_tag_of_filtered_mode(const struct option *opt,
const char *arg, int unset)
{
if (unset || !strcmp(arg, "abort"))
tag_of_filtered_mode = ABORT;
else if (!strcmp(arg, "drop"))
tag_of_filtered_mode = DROP;
else if (!strcmp(arg, "rewrite"))
tag_of_filtered_mode = REWRITE;
else
return error("Unknown tag-of-filtered mode: %s", arg);
return 0;
}
static struct decoration idnums;
static uint32_t last_idnum;
static int has_unshown_parent(struct commit *commit)
{
struct commit_list *parent;
for (parent = commit->parents; parent; parent = parent->next)
if (!(parent->item->object.flags & SHOWN) &&
!(parent->item->object.flags & UNINTERESTING))
return 1;
return 0;
}
/* Since intptr_t is C99, we do not use it here */
static inline uint32_t *mark_to_ptr(uint32_t mark)
{
return ((uint32_t *)NULL) + mark;
}
static inline uint32_t ptr_to_mark(void * mark)
{
return (uint32_t *)mark - (uint32_t *)NULL;
}
static inline void mark_object(struct object *object, uint32_t mark)
{
add_decoration(&idnums, object, mark_to_ptr(mark));
}
static inline void mark_next_object(struct object *object)
{
mark_object(object, ++last_idnum);
}
static int get_object_mark(struct object *object)
{
void *decoration = lookup_decoration(&idnums, object);
if (!decoration)
return 0;
return ptr_to_mark(decoration);
}
static void show_progress(void)
{
static int counter = 0;
if (!progress)
return;
if ((++counter % progress) == 0)
printf("progress %d objects\n", counter);
}
static void handle_object(const unsigned char *sha1)
{
unsigned long size;
enum object_type type;
char *buf;
struct object *object;
if (no_data)
return;
if (is_null_sha1(sha1))
return;
object = parse_object(sha1);
if (!object)
die ("Could not read blob %s", sha1_to_hex(sha1));
if (object->flags & SHOWN)
return;
buf = read_sha1_file(sha1, &type, &size);
if (!buf)
die ("Could not read blob %s", sha1_to_hex(sha1));
mark_next_object(object);
printf("blob\nmark :%"PRIu32"\ndata %lu\n", last_idnum, size);
if (size && fwrite(buf, size, 1, stdout) != 1)
die_errno ("Could not write blob '%s'", sha1_to_hex(sha1));
printf("\n");
show_progress();
object->flags |= SHOWN;
free(buf);
}
static void show_filemodify(struct diff_queue_struct *q,
struct diff_options *options, void *data)
{
int i;
for (i = 0; i < q->nr; i++) {
struct diff_filespec *ospec = q->queue[i]->one;
struct diff_filespec *spec = q->queue[i]->two;
switch (q->queue[i]->status) {
case DIFF_STATUS_DELETED:
printf("D %s\n", spec->path);
break;
case DIFF_STATUS_COPIED:
case DIFF_STATUS_RENAMED:
printf("%c \"%s\" \"%s\"\n", q->queue[i]->status,
ospec->path, spec->path);
if (!hashcmp(ospec->sha1, spec->sha1) &&
ospec->mode == spec->mode)
break;
/* fallthrough */
case DIFF_STATUS_TYPE_CHANGED:
case DIFF_STATUS_MODIFIED:
case DIFF_STATUS_ADDED:
/*
* Links refer to objects in another repositories;
* output the SHA-1 verbatim.
*/
if (no_data || S_ISGITLINK(spec->mode))
printf("M %06o %s %s\n", spec->mode,
sha1_to_hex(spec->sha1), spec->path);
else {
struct object *object = lookup_object(spec->sha1);
printf("M %06o :%d %s\n", spec->mode,
get_object_mark(object), spec->path);
}
break;
default:
die("Unexpected comparison status '%c' for %s, %s",
q->queue[i]->status,
ospec->path ? ospec->path : "none",
spec->path ? spec->path : "none");
}
}
}
static const char *find_encoding(const char *begin, const char *end)
{
const char *needle = "\nencoding ";
char *bol, *eol;
bol = memmem(begin, end ? end - begin : strlen(begin),
needle, strlen(needle));
if (!bol)
return git_commit_encoding;
bol += strlen(needle);
eol = strchrnul(bol, '\n');
*eol = '\0';
return bol;
}
static void handle_commit(struct commit *commit, struct rev_info *rev)
{
int saved_output_format = rev->diffopt.output_format;
const char *author, *author_end, *committer, *committer_end;
const char *encoding, *message;
char *reencoded = NULL;
struct commit_list *p;
int i;
rev->diffopt.output_format = DIFF_FORMAT_CALLBACK;
parse_commit(commit);
author = strstr(commit->buffer, "\nauthor ");
if (!author)
die ("Could not find author in commit %s",
sha1_to_hex(commit->object.sha1));
author++;
author_end = strchrnul(author, '\n');
committer = strstr(author_end, "\ncommitter ");
if (!committer)
die ("Could not find committer in commit %s",
sha1_to_hex(commit->object.sha1));
committer++;
committer_end = strchrnul(committer, '\n');
message = strstr(committer_end, "\n\n");
encoding = find_encoding(committer_end, message);
if (message)
message += 2;
if (commit->parents &&
get_object_mark(&commit->parents->item->object) != 0) {
parse_commit(commit->parents->item);
diff_tree_sha1(commit->parents->item->tree->object.sha1,
commit->tree->object.sha1, "", &rev->diffopt);
}
else
diff_root_tree_sha1(commit->tree->object.sha1,
"", &rev->diffopt);
/* Export the referenced blobs, and remember the marks. */
for (i = 0; i < diff_queued_diff.nr; i++)
if (!S_ISGITLINK(diff_queued_diff.queue[i]->two->mode))
handle_object(diff_queued_diff.queue[i]->two->sha1);
mark_next_object(&commit->object);
if (!is_encoding_utf8(encoding))
reencoded = reencode_string(message, "UTF-8", encoding);
if (!commit->parents)
printf("reset %s\n", (const char*)commit->util);
printf("commit %s\nmark :%"PRIu32"\n%.*s\n%.*s\ndata %u\n%s",
(const char *)commit->util, last_idnum,
(int)(author_end - author), author,
(int)(committer_end - committer), committer,
(unsigned)(reencoded
? strlen(reencoded) : message
? strlen(message) : 0),
reencoded ? reencoded : message ? message : "");
free(reencoded);
for (i = 0, p = commit->parents; p; p = p->next) {
int mark = get_object_mark(&p->item->object);
if (!mark)
continue;
if (i == 0)
printf("from :%d\n", mark);
else
printf("merge :%d\n", mark);
i++;
}
log_tree_diff_flush(rev);
rev->diffopt.output_format = saved_output_format;
printf("\n");
show_progress();
}
static void handle_tail(struct object_array *commits, struct rev_info *revs)
{
struct commit *commit;
while (commits->nr) {
commit = (struct commit *)commits->objects[commits->nr - 1].item;
if (has_unshown_parent(commit))
return;
handle_commit(commit, revs);
commits->nr--;
}
}
static void handle_tag(const char *name, struct tag *tag)
{
unsigned long size;
enum object_type type;
char *buf;
const char *tagger, *tagger_end, *message;
size_t message_size = 0;
struct object *tagged;
int tagged_mark;
struct commit *p;
/* Trees have no identifer in fast-export output, thus we have no way
* to output tags of trees, tags of tags of trees, etc. Simply omit
* such tags.
*/
tagged = tag->tagged;
while (tagged->type == OBJ_TAG) {
tagged = ((struct tag *)tagged)->tagged;
}
if (tagged->type == OBJ_TREE) {
warning("Omitting tag %s,\nsince tags of trees (or tags of tags of trees, etc.) are not supported.",
sha1_to_hex(tag->object.sha1));
return;
}
buf = read_sha1_file(tag->object.sha1, &type, &size);
if (!buf)
die ("Could not read tag %s", sha1_to_hex(tag->object.sha1));
message = memmem(buf, size, "\n\n", 2);
if (message) {
message += 2;
message_size = strlen(message);
}
tagger = memmem(buf, message ? message - buf : size, "\ntagger ", 8);
if (!tagger) {
if (fake_missing_tagger)
tagger = "tagger Unspecified Tagger "
"<unspecified-tagger> 0 +0000";
else
tagger = "";
tagger_end = tagger + strlen(tagger);
} else {
tagger++;
tagger_end = strchrnul(tagger, '\n');
}
/* handle signed tags */
if (message) {
const char *signature = strstr(message,
"\n-----BEGIN PGP SIGNATURE-----\n");
if (signature)
switch(signed_tag_mode) {
case ABORT:
die ("Encountered signed tag %s; use "
"--signed-tag=<mode> to handle it.",
sha1_to_hex(tag->object.sha1));
case WARN:
warning ("Exporting signed tag %s",
sha1_to_hex(tag->object.sha1));
/* fallthru */
case VERBATIM:
break;
case STRIP:
message_size = signature + 1 - message;
break;
}
}
/* handle tag->tagged having been filtered out due to paths specified */
tagged = tag->tagged;
tagged_mark = get_object_mark(tagged);
if (!tagged_mark) {
switch(tag_of_filtered_mode) {
case ABORT:
die ("Tag %s tags unexported object; use "
"--tag-of-filtered-object=<mode> to handle it.",
sha1_to_hex(tag->object.sha1));
case DROP:
/* Ignore this tag altogether */
return;
case REWRITE:
if (tagged->type != OBJ_COMMIT) {
die ("Tag %s tags unexported %s!",
sha1_to_hex(tag->object.sha1),
typename(tagged->type));
}
p = (struct commit *)tagged;
for (;;) {
if (p->parents && p->parents->next)
break;
if (p->object.flags & UNINTERESTING)
break;
if (!(p->object.flags & TREESAME))
break;
if (!p->parents)
die ("Can't find replacement commit for tag %s\n",
sha1_to_hex(tag->object.sha1));
p = p->parents->item;
}
tagged_mark = get_object_mark(&p->object);
}
}
if (!prefixcmp(name, "refs/tags/"))
name += 10;
printf("tag %s\nfrom :%d\n%.*s%sdata %d\n%.*s\n",
name, tagged_mark,
(int)(tagger_end - tagger), tagger,
tagger == tagger_end ? "" : "\n",
(int)message_size, (int)message_size, message ? message : "");
}
static void get_tags_and_duplicates(struct object_array *pending,
struct string_list *extra_refs)
{
struct tag *tag;
int i;
for (i = 0; i < pending->nr; i++) {
struct object_array_entry *e = pending->objects + i;
unsigned char sha1[20];
struct commit *commit = commit;
char *full_name;
if (dwim_ref(e->name, strlen(e->name), sha1, &full_name) != 1)
continue;
switch (e->item->type) {
case OBJ_COMMIT:
commit = (struct commit *)e->item;
break;
case OBJ_TAG:
tag = (struct tag *)e->item;
/* handle nested tags */
while (tag && tag->object.type == OBJ_TAG) {
parse_object(tag->object.sha1);
string_list_append(full_name, extra_refs)->util = tag;
tag = (struct tag *)tag->tagged;
}
if (!tag)
die ("Tag %s points nowhere?", e->name);
switch(tag->object.type) {
case OBJ_COMMIT:
commit = (struct commit *)tag;
break;
case OBJ_BLOB:
handle_object(tag->object.sha1);
continue;
default: /* OBJ_TAG (nested tags) is already handled */
warning("Tag points to object of unexpected type %s, skipping.",
typename(tag->object.type));
continue;
}
break;
default:
warning("%s: Unexpected object of type %s, skipping.",
e->name,
typename(e->item->type));
continue;
}
if (commit->util)
/* more than one name for the same object */
string_list_append(full_name, extra_refs)->util = commit;
else
commit->util = full_name;
}
}
static void handle_tags_and_duplicates(struct string_list *extra_refs)
{
struct commit *commit;
int i;
for (i = extra_refs->nr - 1; i >= 0; i--) {
const char *name = extra_refs->items[i].string;
struct object *object = extra_refs->items[i].util;
switch (object->type) {
case OBJ_TAG:
handle_tag(name, (struct tag *)object);
break;
case OBJ_COMMIT:
/* create refs pointing to already seen commits */
commit = (struct commit *)object;
printf("reset %s\nfrom :%d\n\n", name,
get_object_mark(&commit->object));
show_progress();
break;
}
}
}
static void export_marks(char *file)
{
unsigned int i;
uint32_t mark;
struct object_decoration *deco = idnums.hash;
FILE *f;
int e = 0;
f = fopen(file, "w");
if (!f)
error("Unable to open marks file %s for writing.", file);
for (i = 0; i < idnums.size; i++) {
if (deco->base && deco->base->type == 1) {
mark = ptr_to_mark(deco->decoration);
if (fprintf(f, ":%"PRIu32" %s\n", mark,
sha1_to_hex(deco->base->sha1)) < 0) {
e = 1;
break;
}
}
deco++;
}
e |= ferror(f);
e |= fclose(f);
if (e)
error("Unable to write marks file %s.", file);
}
static void import_marks(char *input_file)
{
char line[512];
FILE *f = fopen(input_file, "r");
if (!f)
die_errno("cannot read '%s'", input_file);
while (fgets(line, sizeof(line), f)) {
uint32_t mark;
char *line_end, *mark_end;
unsigned char sha1[20];
struct object *object;
line_end = strchr(line, '\n');
if (line[0] != ':' || !line_end)
die("corrupt mark line: %s", line);
*line_end = '\0';
mark = strtoumax(line + 1, &mark_end, 10);
if (!mark || mark_end == line + 1
|| *mark_end != ' ' || get_sha1(mark_end + 1, sha1))
die("corrupt mark line: %s", line);
object = parse_object(sha1);
if (!object)
die ("Could not read blob %s", sha1_to_hex(sha1));
if (object->flags & SHOWN)
error("Object %s already has a mark", sha1);
mark_object(object, mark);
if (last_idnum < mark)
last_idnum = mark;
object->flags |= SHOWN;
}
fclose(f);
}
int cmd_fast_export(int argc, const char **argv, const char *prefix)
{
struct rev_info revs;
struct object_array commits = { 0, 0, NULL };
struct string_list extra_refs = { NULL, 0, 0, 0 };
struct commit *commit;
char *export_filename = NULL, *import_filename = NULL;
struct option options[] = {
OPT_INTEGER(0, "progress", &progress,
"show progress after <n> objects"),
OPT_CALLBACK(0, "signed-tags", &signed_tag_mode, "mode",
"select handling of signed tags",
parse_opt_signed_tag_mode),
OPT_CALLBACK(0, "tag-of-filtered-object", &tag_of_filtered_mode, "mode",
"select handling of tags that tag filtered objects",
parse_opt_tag_of_filtered_mode),
OPT_STRING(0, "export-marks", &export_filename, "FILE",
"Dump marks to this file"),
OPT_STRING(0, "import-marks", &import_filename, "FILE",
"Import marks from this file"),
OPT_BOOLEAN(0, "fake-missing-tagger", &fake_missing_tagger,
"Fake a tagger when tags lack one"),
{ OPTION_NEGBIT, 0, "data", &no_data, NULL,
"Skip output of blob data",
PARSE_OPT_NOARG | PARSE_OPT_NEGHELP, NULL, 1 },
OPT_END()
};
if (argc == 1)
usage_with_options (fast_export_usage, options);
/* we handle encodings */
git_config(git_default_config, NULL);
init_revisions(&revs, prefix);
revs.topo_order = 1;
revs.show_source = 1;
revs.rewrite_parents = 1;
argc = setup_revisions(argc, argv, &revs, NULL);
argc = parse_options(argc, argv, prefix, options, fast_export_usage, 0);
if (argc > 1)
usage_with_options (fast_export_usage, options);
if (import_filename)
import_marks(import_filename);
get_tags_and_duplicates(&revs.pending, &extra_refs);
if (prepare_revision_walk(&revs))
die("revision walk setup failed");
revs.diffopt.format_callback = show_filemodify;
DIFF_OPT_SET(&revs.diffopt, RECURSIVE);
while ((commit = get_revision(&revs))) {
if (has_unshown_parent(commit)) {
add_object_array(&commit->object, NULL, &commits);
}
else {
handle_commit(commit, &revs);
handle_tail(&commits, &revs);
}
}
handle_tags_and_duplicates(&extra_refs);
if (export_filename)
export_marks(export_filename);
return 0;
}