git/rerere.c
Michael Haggerty 697cc8efd9 lockfile.h: extract new header file for the functions in lockfile.c
Move the interface declaration for the functions in lockfile.c from
cache.h to a new file, lockfile.h. Add #includes where necessary (and
remove some redundant includes of cache.h by files that already
include builtin.h).

Move the documentation of the lock_file state diagram from lockfile.c
to the new header file.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-01 13:56:14 -07:00

748 lines
18 KiB
C

#include "cache.h"
#include "lockfile.h"
#include "string-list.h"
#include "rerere.h"
#include "xdiff-interface.h"
#include "dir.h"
#include "resolve-undo.h"
#include "ll-merge.h"
#include "attr.h"
#include "pathspec.h"
#define RESOLVED 0
#define PUNTED 1
#define THREE_STAGED 2
void *RERERE_RESOLVED = &RERERE_RESOLVED;
/* if rerere_enabled == -1, fall back to detection of .git/rr-cache */
static int rerere_enabled = -1;
/* automatically update cleanly resolved paths to the index */
static int rerere_autoupdate;
static char *merge_rr_path;
const char *rerere_path(const char *hex, const char *file)
{
return git_path("rr-cache/%s/%s", hex, file);
}
static int has_rerere_resolution(const char *hex)
{
struct stat st;
return !stat(rerere_path(hex, "postimage"), &st);
}
static void read_rr(struct string_list *rr)
{
unsigned char sha1[20];
char buf[PATH_MAX];
FILE *in = fopen(merge_rr_path, "r");
if (!in)
return;
while (fread(buf, 40, 1, in) == 1) {
int i;
char *name;
if (get_sha1_hex(buf, sha1))
die("corrupt MERGE_RR");
buf[40] = '\0';
name = xstrdup(buf);
if (fgetc(in) != '\t')
die("corrupt MERGE_RR");
for (i = 0; i < sizeof(buf); i++) {
int c = fgetc(in);
if (c < 0)
die("corrupt MERGE_RR");
buf[i] = c;
if (c == 0)
break;
}
if (i == sizeof(buf))
die("filename too long");
string_list_insert(rr, buf)->util = name;
}
fclose(in);
}
static struct lock_file write_lock;
static int write_rr(struct string_list *rr, int out_fd)
{
int i;
for (i = 0; i < rr->nr; i++) {
const char *path;
int length;
if (!rr->items[i].util)
continue;
path = rr->items[i].string;
length = strlen(path) + 1;
if (write_in_full(out_fd, rr->items[i].util, 40) != 40 ||
write_str_in_full(out_fd, "\t") != 1 ||
write_in_full(out_fd, path, length) != length)
die("unable to write rerere record");
}
if (commit_lock_file(&write_lock) != 0)
die("unable to write rerere record");
return 0;
}
static void ferr_write(const void *p, size_t count, FILE *fp, int *err)
{
if (!count || *err)
return;
if (fwrite(p, count, 1, fp) != 1)
*err = errno;
}
static inline void ferr_puts(const char *s, FILE *fp, int *err)
{
ferr_write(s, strlen(s), fp, err);
}
struct rerere_io {
int (*getline)(struct strbuf *, struct rerere_io *);
FILE *output;
int wrerror;
/* some more stuff */
};
static void rerere_io_putstr(const char *str, struct rerere_io *io)
{
if (io->output)
ferr_puts(str, io->output, &io->wrerror);
}
static void rerere_io_putconflict(int ch, int size, struct rerere_io *io)
{
char buf[64];
while (size) {
if (size < sizeof(buf) - 2) {
memset(buf, ch, size);
buf[size] = '\n';
buf[size + 1] = '\0';
size = 0;
} else {
int sz = sizeof(buf) - 1;
if (size <= sz)
sz -= (sz - size) + 1;
memset(buf, ch, sz);
buf[sz] = '\0';
size -= sz;
}
rerere_io_putstr(buf, io);
}
}
static void rerere_io_putmem(const char *mem, size_t sz, struct rerere_io *io)
{
if (io->output)
ferr_write(mem, sz, io->output, &io->wrerror);
}
struct rerere_io_file {
struct rerere_io io;
FILE *input;
};
static int rerere_file_getline(struct strbuf *sb, struct rerere_io *io_)
{
struct rerere_io_file *io = (struct rerere_io_file *)io_;
return strbuf_getwholeline(sb, io->input, '\n');
}
static int is_cmarker(char *buf, int marker_char, int marker_size, int want_sp)
{
while (marker_size--)
if (*buf++ != marker_char)
return 0;
if (want_sp && *buf != ' ')
return 0;
return isspace(*buf);
}
static int handle_path(unsigned char *sha1, struct rerere_io *io, int marker_size)
{
git_SHA_CTX ctx;
int hunk_no = 0;
enum {
RR_CONTEXT = 0, RR_SIDE_1, RR_SIDE_2, RR_ORIGINAL
} hunk = RR_CONTEXT;
struct strbuf one = STRBUF_INIT, two = STRBUF_INIT;
struct strbuf buf = STRBUF_INIT;
if (sha1)
git_SHA1_Init(&ctx);
while (!io->getline(&buf, io)) {
if (is_cmarker(buf.buf, '<', marker_size, 1)) {
if (hunk != RR_CONTEXT)
goto bad;
hunk = RR_SIDE_1;
} else if (is_cmarker(buf.buf, '|', marker_size, 0)) {
if (hunk != RR_SIDE_1)
goto bad;
hunk = RR_ORIGINAL;
} else if (is_cmarker(buf.buf, '=', marker_size, 0)) {
if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
goto bad;
hunk = RR_SIDE_2;
} else if (is_cmarker(buf.buf, '>', marker_size, 1)) {
if (hunk != RR_SIDE_2)
goto bad;
if (strbuf_cmp(&one, &two) > 0)
strbuf_swap(&one, &two);
hunk_no++;
hunk = RR_CONTEXT;
rerere_io_putconflict('<', marker_size, io);
rerere_io_putmem(one.buf, one.len, io);
rerere_io_putconflict('=', marker_size, io);
rerere_io_putmem(two.buf, two.len, io);
rerere_io_putconflict('>', marker_size, io);
if (sha1) {
git_SHA1_Update(&ctx, one.buf ? one.buf : "",
one.len + 1);
git_SHA1_Update(&ctx, two.buf ? two.buf : "",
two.len + 1);
}
strbuf_reset(&one);
strbuf_reset(&two);
} else if (hunk == RR_SIDE_1)
strbuf_addbuf(&one, &buf);
else if (hunk == RR_ORIGINAL)
; /* discard */
else if (hunk == RR_SIDE_2)
strbuf_addbuf(&two, &buf);
else
rerere_io_putstr(buf.buf, io);
continue;
bad:
hunk = 99; /* force error exit */
break;
}
strbuf_release(&one);
strbuf_release(&two);
strbuf_release(&buf);
if (sha1)
git_SHA1_Final(sha1, &ctx);
if (hunk != RR_CONTEXT)
return -1;
return hunk_no;
}
static int handle_file(const char *path, unsigned char *sha1, const char *output)
{
int hunk_no = 0;
struct rerere_io_file io;
int marker_size = ll_merge_marker_size(path);
memset(&io, 0, sizeof(io));
io.io.getline = rerere_file_getline;
io.input = fopen(path, "r");
io.io.wrerror = 0;
if (!io.input)
return error("Could not open %s", path);
if (output) {
io.io.output = fopen(output, "w");
if (!io.io.output) {
fclose(io.input);
return error("Could not write %s", output);
}
}
hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
fclose(io.input);
if (io.io.wrerror)
error("There were errors while writing %s (%s)",
path, strerror(io.io.wrerror));
if (io.io.output && fclose(io.io.output))
io.io.wrerror = error("Failed to flush %s: %s",
path, strerror(errno));
if (hunk_no < 0) {
if (output)
unlink_or_warn(output);
return error("Could not parse conflict hunks in %s", path);
}
if (io.io.wrerror)
return -1;
return hunk_no;
}
struct rerere_io_mem {
struct rerere_io io;
struct strbuf input;
};
static int rerere_mem_getline(struct strbuf *sb, struct rerere_io *io_)
{
struct rerere_io_mem *io = (struct rerere_io_mem *)io_;
char *ep;
size_t len;
strbuf_release(sb);
if (!io->input.len)
return -1;
ep = memchr(io->input.buf, '\n', io->input.len);
if (!ep)
ep = io->input.buf + io->input.len;
else if (*ep == '\n')
ep++;
len = ep - io->input.buf;
strbuf_add(sb, io->input.buf, len);
strbuf_remove(&io->input, 0, len);
return 0;
}
static int handle_cache(const char *path, unsigned char *sha1, const char *output)
{
mmfile_t mmfile[3] = {{NULL}};
mmbuffer_t result = {NULL, 0};
const struct cache_entry *ce;
int pos, len, i, hunk_no;
struct rerere_io_mem io;
int marker_size = ll_merge_marker_size(path);
/*
* Reproduce the conflicted merge in-core
*/
len = strlen(path);
pos = cache_name_pos(path, len);
if (0 <= pos)
return -1;
pos = -pos - 1;
for (i = 0; i < 3; i++) {
enum object_type type;
unsigned long size;
int j;
if (active_nr <= pos)
break;
ce = active_cache[pos++];
if (ce_namelen(ce) != len || memcmp(ce->name, path, len))
continue;
j = ce_stage(ce) - 1;
mmfile[j].ptr = read_sha1_file(ce->sha1, &type, &size);
mmfile[j].size = size;
}
for (i = 0; i < 3; i++) {
if (!mmfile[i].ptr && !mmfile[i].size)
mmfile[i].ptr = xstrdup("");
}
/*
* NEEDSWORK: handle conflicts from merges with
* merge.renormalize set, too
*/
ll_merge(&result, path, &mmfile[0], NULL,
&mmfile[1], "ours",
&mmfile[2], "theirs", NULL);
for (i = 0; i < 3; i++)
free(mmfile[i].ptr);
memset(&io, 0, sizeof(io));
io.io.getline = rerere_mem_getline;
if (output)
io.io.output = fopen(output, "w");
else
io.io.output = NULL;
strbuf_init(&io.input, 0);
strbuf_attach(&io.input, result.ptr, result.size, result.size);
hunk_no = handle_path(sha1, (struct rerere_io *)&io, marker_size);
strbuf_release(&io.input);
if (io.io.output)
fclose(io.io.output);
return hunk_no;
}
static int check_one_conflict(int i, int *type)
{
const struct cache_entry *e = active_cache[i];
if (!ce_stage(e)) {
*type = RESOLVED;
return i + 1;
}
*type = PUNTED;
if (ce_stage(e) == 1) {
if (active_nr <= ++i)
return i + 1;
}
/* Only handle regular files with both stages #2 and #3 */
if (i + 1 < active_nr) {
const struct cache_entry *e2 = active_cache[i];
const struct cache_entry *e3 = active_cache[i + 1];
if (ce_stage(e2) == 2 &&
ce_stage(e3) == 3 &&
ce_same_name(e, e3) &&
S_ISREG(e2->ce_mode) &&
S_ISREG(e3->ce_mode))
*type = THREE_STAGED;
}
/* Skip the entries with the same name */
while (i < active_nr && ce_same_name(e, active_cache[i]))
i++;
return i;
}
static int find_conflict(struct string_list *conflict)
{
int i;
if (read_cache() < 0)
return error("Could not read index");
for (i = 0; i < active_nr;) {
int conflict_type;
const struct cache_entry *e = active_cache[i];
i = check_one_conflict(i, &conflict_type);
if (conflict_type == THREE_STAGED)
string_list_insert(conflict, (const char *)e->name);
}
return 0;
}
int rerere_remaining(struct string_list *merge_rr)
{
int i;
if (read_cache() < 0)
return error("Could not read index");
for (i = 0; i < active_nr;) {
int conflict_type;
const struct cache_entry *e = active_cache[i];
i = check_one_conflict(i, &conflict_type);
if (conflict_type == PUNTED)
string_list_insert(merge_rr, (const char *)e->name);
else if (conflict_type == RESOLVED) {
struct string_list_item *it;
it = string_list_lookup(merge_rr, (const char *)e->name);
if (it != NULL) {
free(it->util);
it->util = RERERE_RESOLVED;
}
}
}
return 0;
}
static int merge(const char *name, const char *path)
{
int ret;
mmfile_t cur = {NULL, 0}, base = {NULL, 0}, other = {NULL, 0};
mmbuffer_t result = {NULL, 0};
if (handle_file(path, NULL, rerere_path(name, "thisimage")) < 0)
return 1;
if (read_mmfile(&cur, rerere_path(name, "thisimage")) ||
read_mmfile(&base, rerere_path(name, "preimage")) ||
read_mmfile(&other, rerere_path(name, "postimage"))) {
ret = 1;
goto out;
}
ret = ll_merge(&result, path, &base, NULL, &cur, "", &other, "", NULL);
if (!ret) {
FILE *f;
if (utime(rerere_path(name, "postimage"), NULL) < 0)
warning("failed utime() on %s: %s",
rerere_path(name, "postimage"),
strerror(errno));
f = fopen(path, "w");
if (!f)
return error("Could not open %s: %s", path,
strerror(errno));
if (fwrite(result.ptr, result.size, 1, f) != 1)
error("Could not write %s: %s", path, strerror(errno));
if (fclose(f))
return error("Writing %s failed: %s", path,
strerror(errno));
}
out:
free(cur.ptr);
free(base.ptr);
free(other.ptr);
free(result.ptr);
return ret;
}
static struct lock_file index_lock;
static int update_paths(struct string_list *update)
{
int i;
int fd = hold_locked_index(&index_lock, 0);
int status = 0;
if (fd < 0)
return -1;
for (i = 0; i < update->nr; i++) {
struct string_list_item *item = &update->items[i];
if (add_file_to_cache(item->string, ADD_CACHE_IGNORE_ERRORS))
status = -1;
}
if (!status && active_cache_changed) {
if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
die("Unable to write new index file");
} else if (fd >= 0)
rollback_lock_file(&index_lock);
return status;
}
static int do_plain_rerere(struct string_list *rr, int fd)
{
struct string_list conflict = STRING_LIST_INIT_DUP;
struct string_list update = STRING_LIST_INIT_DUP;
int i;
find_conflict(&conflict);
/*
* MERGE_RR records paths with conflicts immediately after merge
* failed. Some of the conflicted paths might have been hand resolved
* in the working tree since then, but the initial run would catch all
* and register their preimages.
*/
for (i = 0; i < conflict.nr; i++) {
const char *path = conflict.items[i].string;
if (!string_list_has_string(rr, path)) {
unsigned char sha1[20];
char *hex;
int ret;
ret = handle_file(path, sha1, NULL);
if (ret < 1)
continue;
hex = xstrdup(sha1_to_hex(sha1));
string_list_insert(rr, path)->util = hex;
if (mkdir_in_gitdir(git_path("rr-cache/%s", hex)))
continue;
handle_file(path, NULL, rerere_path(hex, "preimage"));
fprintf(stderr, "Recorded preimage for '%s'\n", path);
}
}
/*
* Now some of the paths that had conflicts earlier might have been
* hand resolved. Others may be similar to a conflict already that
* was resolved before.
*/
for (i = 0; i < rr->nr; i++) {
int ret;
const char *path = rr->items[i].string;
const char *name = (const char *)rr->items[i].util;
if (has_rerere_resolution(name)) {
if (!merge(name, path)) {
const char *msg;
if (rerere_autoupdate) {
string_list_insert(&update, path);
msg = "Staged '%s' using previous resolution.\n";
} else
msg = "Resolved '%s' using previous resolution.\n";
fprintf(stderr, msg, path);
goto mark_resolved;
}
}
/* Let's see if we have resolved it. */
ret = handle_file(path, NULL, NULL);
if (ret)
continue;
fprintf(stderr, "Recorded resolution for '%s'.\n", path);
copy_file(rerere_path(name, "postimage"), path, 0666);
mark_resolved:
rr->items[i].util = NULL;
}
if (update.nr)
update_paths(&update);
return write_rr(rr, fd);
}
static void git_rerere_config(void)
{
git_config_get_bool("rerere.enabled", &rerere_enabled);
git_config_get_bool("rerere.autoupdate", &rerere_autoupdate);
git_config(git_default_config, NULL);
}
static int is_rerere_enabled(void)
{
const char *rr_cache;
int rr_cache_exists;
if (!rerere_enabled)
return 0;
rr_cache = git_path("rr-cache");
rr_cache_exists = is_directory(rr_cache);
if (rerere_enabled < 0)
return rr_cache_exists;
if (!rr_cache_exists && mkdir_in_gitdir(rr_cache))
die("Could not create directory %s", rr_cache);
return 1;
}
int setup_rerere(struct string_list *merge_rr, int flags)
{
int fd;
git_rerere_config();
if (!is_rerere_enabled())
return -1;
if (flags & (RERERE_AUTOUPDATE|RERERE_NOAUTOUPDATE))
rerere_autoupdate = !!(flags & RERERE_AUTOUPDATE);
merge_rr_path = git_pathdup("MERGE_RR");
fd = hold_lock_file_for_update(&write_lock, merge_rr_path,
LOCK_DIE_ON_ERROR);
read_rr(merge_rr);
return fd;
}
int rerere(int flags)
{
struct string_list merge_rr = STRING_LIST_INIT_DUP;
int fd;
fd = setup_rerere(&merge_rr, flags);
if (fd < 0)
return 0;
return do_plain_rerere(&merge_rr, fd);
}
static int rerere_forget_one_path(const char *path, struct string_list *rr)
{
const char *filename;
char *hex;
unsigned char sha1[20];
int ret;
ret = handle_cache(path, sha1, NULL);
if (ret < 1)
return error("Could not parse conflict hunks in '%s'", path);
hex = xstrdup(sha1_to_hex(sha1));
filename = rerere_path(hex, "postimage");
if (unlink(filename))
return (errno == ENOENT
? error("no remembered resolution for %s", path)
: error("cannot unlink %s: %s", filename, strerror(errno)));
handle_cache(path, sha1, rerere_path(hex, "preimage"));
fprintf(stderr, "Updated preimage for '%s'\n", path);
string_list_insert(rr, path)->util = hex;
fprintf(stderr, "Forgot resolution for %s\n", path);
return 0;
}
int rerere_forget(struct pathspec *pathspec)
{
int i, fd;
struct string_list conflict = STRING_LIST_INIT_DUP;
struct string_list merge_rr = STRING_LIST_INIT_DUP;
if (read_cache() < 0)
return error("Could not read index");
fd = setup_rerere(&merge_rr, RERERE_NOAUTOUPDATE);
unmerge_cache(pathspec);
find_conflict(&conflict);
for (i = 0; i < conflict.nr; i++) {
struct string_list_item *it = &conflict.items[i];
if (!match_pathspec(pathspec, it->string,
strlen(it->string), 0, NULL, 0))
continue;
rerere_forget_one_path(it->string, &merge_rr);
}
return write_rr(&merge_rr, fd);
}
static time_t rerere_created_at(const char *name)
{
struct stat st;
return stat(rerere_path(name, "preimage"), &st) ? (time_t) 0 : st.st_mtime;
}
static time_t rerere_last_used_at(const char *name)
{
struct stat st;
return stat(rerere_path(name, "postimage"), &st) ? (time_t) 0 : st.st_mtime;
}
static void unlink_rr_item(const char *name)
{
unlink(rerere_path(name, "thisimage"));
unlink(rerere_path(name, "preimage"));
unlink(rerere_path(name, "postimage"));
rmdir(git_path("rr-cache/%s", name));
}
void rerere_gc(struct string_list *rr)
{
struct string_list to_remove = STRING_LIST_INIT_DUP;
DIR *dir;
struct dirent *e;
int i, cutoff;
time_t now = time(NULL), then;
int cutoff_noresolve = 15;
int cutoff_resolve = 60;
git_config_get_int("gc.rerereresolved", &cutoff_resolve);
git_config_get_int("gc.rerereunresolved", &cutoff_noresolve);
git_config(git_default_config, NULL);
dir = opendir(git_path("rr-cache"));
if (!dir)
die_errno("unable to open rr-cache directory");
while ((e = readdir(dir))) {
if (is_dot_or_dotdot(e->d_name))
continue;
then = rerere_last_used_at(e->d_name);
if (then) {
cutoff = cutoff_resolve;
} else {
then = rerere_created_at(e->d_name);
if (!then)
continue;
cutoff = cutoff_noresolve;
}
if (then < now - cutoff * 86400)
string_list_append(&to_remove, e->d_name);
}
closedir(dir);
for (i = 0; i < to_remove.nr; i++)
unlink_rr_item(to_remove.items[i].string);
string_list_clear(&to_remove, 0);
}
void rerere_clear(struct string_list *merge_rr)
{
int i;
for (i = 0; i < merge_rr->nr; i++) {
const char *name = (const char *)merge_rr->items[i].util;
if (!has_rerere_resolution(name))
unlink_rr_item(name);
}
unlink_or_warn(git_path("MERGE_RR"));
}