git/rerere.c
Junio C Hamano b3e83cc752 hold_locked_index(): align error handling with hold_lockfile_for_update()
Callers of the hold_locked_index() function pass 0 when they want to
prepare to write a new version of the index file without wishing to
die or emit an error message when the request fails (e.g. somebody
else already held the lock), and pass 1 when they want the call to
die upon failure.

This option is called LOCK_DIE_ON_ERROR by the underlying lockfile
API, and the hold_locked_index() function translates the paramter to
LOCK_DIE_ON_ERROR when calling the hold_lock_file_for_update().

Replace these hardcoded '1' with LOCK_DIE_ON_ERROR and stop
translating.  Callers other than the ones that are replaced with
this change pass '0' to the function; no behaviour change is
intended with this patch.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

Among the callers of hold_locked_index() that passes 0:

 - diff.c::refresh_index_quietly() at the end of "git diff" is an
   opportunistic update; it leaks the lockfile structure but it is
   just before the program exits and nobody should care.

 - builtin/describe.c::cmd_describe(),
   builtin/commit.c::cmd_status(),
   sequencer.c::read_and_refresh_cache() are all opportunistic
   updates and they are OK.

 - builtin/update-index.c::cmd_update_index() takes a lock upfront
   but we may end up not needing to update the index (i.e. the
   entries may be fully up-to-date), in which case we do not need to
   issue an error upon failure to acquire the lock.  We do diagnose
   and die if we indeed need to update, so it is OK.

 - wt-status.c::require_clean_work_tree() IS BUGGY.  It asks
   silence, does not check the returned value.  Compare with
   callsites like cmd_describe() and cmd_status() to notice that it
   is wrong to call update_index_if_able() unconditionally.
2016-12-07 11:31:59 -08:00

1253 lines
31 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"
#include "sha1-lookup.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 int rerere_dir_nr;
static int rerere_dir_alloc;
#define RR_HAS_POSTIMAGE 1
#define RR_HAS_PREIMAGE 2
static struct rerere_dir {
unsigned char sha1[20];
int status_alloc, status_nr;
unsigned char *status;
} **rerere_dir;
static void free_rerere_dirs(void)
{
int i;
for (i = 0; i < rerere_dir_nr; i++) {
free(rerere_dir[i]->status);
free(rerere_dir[i]);
}
free(rerere_dir);
rerere_dir_nr = rerere_dir_alloc = 0;
rerere_dir = NULL;
}
static void free_rerere_id(struct string_list_item *item)
{
free(item->util);
}
static const char *rerere_id_hex(const struct rerere_id *id)
{
return sha1_to_hex(id->collection->sha1);
}
static void fit_variant(struct rerere_dir *rr_dir, int variant)
{
variant++;
ALLOC_GROW(rr_dir->status, variant, rr_dir->status_alloc);
if (rr_dir->status_nr < variant) {
memset(rr_dir->status + rr_dir->status_nr,
'\0', variant - rr_dir->status_nr);
rr_dir->status_nr = variant;
}
}
static void assign_variant(struct rerere_id *id)
{
int variant;
struct rerere_dir *rr_dir = id->collection;
variant = id->variant;
if (variant < 0) {
for (variant = 0; variant < rr_dir->status_nr; variant++)
if (!rr_dir->status[variant])
break;
}
fit_variant(rr_dir, variant);
id->variant = variant;
}
const char *rerere_path(const struct rerere_id *id, const char *file)
{
if (!file)
return git_path("rr-cache/%s", rerere_id_hex(id));
if (id->variant <= 0)
return git_path("rr-cache/%s/%s", rerere_id_hex(id), file);
return git_path("rr-cache/%s/%s.%d",
rerere_id_hex(id), file, id->variant);
}
static int is_rr_file(const char *name, const char *filename, int *variant)
{
const char *suffix;
char *ep;
if (!strcmp(name, filename)) {
*variant = 0;
return 1;
}
if (!skip_prefix(name, filename, &suffix) || *suffix != '.')
return 0;
errno = 0;
*variant = strtol(suffix + 1, &ep, 10);
if (errno || *ep)
return 0;
return 1;
}
static void scan_rerere_dir(struct rerere_dir *rr_dir)
{
struct dirent *de;
DIR *dir = opendir(git_path("rr-cache/%s", sha1_to_hex(rr_dir->sha1)));
if (!dir)
return;
while ((de = readdir(dir)) != NULL) {
int variant;
if (is_rr_file(de->d_name, "postimage", &variant)) {
fit_variant(rr_dir, variant);
rr_dir->status[variant] |= RR_HAS_POSTIMAGE;
} else if (is_rr_file(de->d_name, "preimage", &variant)) {
fit_variant(rr_dir, variant);
rr_dir->status[variant] |= RR_HAS_PREIMAGE;
}
}
closedir(dir);
}
static const unsigned char *rerere_dir_sha1(size_t i, void *table)
{
struct rerere_dir **rr_dir = table;
return rr_dir[i]->sha1;
}
static struct rerere_dir *find_rerere_dir(const char *hex)
{
unsigned char sha1[20];
struct rerere_dir *rr_dir;
int pos;
if (get_sha1_hex(hex, sha1))
return NULL; /* BUG */
pos = sha1_pos(sha1, rerere_dir, rerere_dir_nr, rerere_dir_sha1);
if (pos < 0) {
rr_dir = xmalloc(sizeof(*rr_dir));
hashcpy(rr_dir->sha1, sha1);
rr_dir->status = NULL;
rr_dir->status_nr = 0;
rr_dir->status_alloc = 0;
pos = -1 - pos;
/* Make sure the array is big enough ... */
ALLOC_GROW(rerere_dir, rerere_dir_nr + 1, rerere_dir_alloc);
/* ... and add it in. */
rerere_dir_nr++;
memmove(rerere_dir + pos + 1, rerere_dir + pos,
(rerere_dir_nr - pos - 1) * sizeof(*rerere_dir));
rerere_dir[pos] = rr_dir;
scan_rerere_dir(rr_dir);
}
return rerere_dir[pos];
}
static int has_rerere_resolution(const struct rerere_id *id)
{
const int both = RR_HAS_POSTIMAGE|RR_HAS_PREIMAGE;
int variant = id->variant;
if (variant < 0)
return 0;
return ((id->collection->status[variant] & both) == both);
}
static struct rerere_id *new_rerere_id_hex(char *hex)
{
struct rerere_id *id = xmalloc(sizeof(*id));
id->collection = find_rerere_dir(hex);
id->variant = -1; /* not known yet */
return id;
}
static struct rerere_id *new_rerere_id(unsigned char *sha1)
{
return new_rerere_id_hex(sha1_to_hex(sha1));
}
/*
* $GIT_DIR/MERGE_RR file is a collection of records, each of which is
* "conflict ID", a HT and pathname, terminated with a NUL, and is
* used to keep track of the set of paths that "rerere" may need to
* work on (i.e. what is left by the previous invocation of "git
* rerere" during the current conflict resolution session).
*/
static void read_rr(struct string_list *rr)
{
struct strbuf buf = STRBUF_INIT;
FILE *in = fopen(git_path_merge_rr(), "r");
if (!in)
return;
while (!strbuf_getwholeline(&buf, in, '\0')) {
char *path;
unsigned char sha1[20];
struct rerere_id *id;
int variant;
/* There has to be the hash, tab, path and then NUL */
if (buf.len < 42 || get_sha1_hex(buf.buf, sha1))
die("corrupt MERGE_RR");
if (buf.buf[40] != '.') {
variant = 0;
path = buf.buf + 40;
} else {
errno = 0;
variant = strtol(buf.buf + 41, &path, 10);
if (errno)
die("corrupt MERGE_RR");
}
if (*(path++) != '\t')
die("corrupt MERGE_RR");
buf.buf[40] = '\0';
id = new_rerere_id_hex(buf.buf);
id->variant = variant;
string_list_insert(rr, path)->util = id;
}
strbuf_release(&buf);
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++) {
struct strbuf buf = STRBUF_INIT;
struct rerere_id *id;
assert(rr->items[i].util != RERERE_RESOLVED);
id = rr->items[i].util;
if (!id)
continue;
assert(id->variant >= 0);
if (0 < id->variant)
strbuf_addf(&buf, "%s.%d\t%s%c",
rerere_id_hex(id), id->variant,
rr->items[i].string, 0);
else
strbuf_addf(&buf, "%s\t%s%c",
rerere_id_hex(id),
rr->items[i].string, 0);
if (write_in_full(out_fd, buf.buf, buf.len) != buf.len)
die("unable to write rerere record");
strbuf_release(&buf);
}
if (commit_lock_file(&write_lock) != 0)
die("unable to write rerere record");
return 0;
}
/*
* "rerere" interacts with conflicted file contents using this I/O
* abstraction. It reads a conflicted contents from one place via
* "getline()" method, and optionally can write it out after
* normalizing the conflicted hunks to the "output". Subclasses of
* rerere_io embed this structure at the beginning of their own
* rerere_io object.
*/
struct rerere_io {
int (*getline)(struct strbuf *, struct rerere_io *);
FILE *output;
int wrerror;
/* some more stuff */
};
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);
}
static void rerere_io_putstr(const char *str, struct rerere_io *io)
{
if (io->output)
ferr_puts(str, io->output, &io->wrerror);
}
/*
* Write a conflict marker to io->output (if defined).
*/
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;
/*
* Make sure we will not write everything out
* in this round by leaving at least 1 byte
* for the next round, giving the next round
* a chance to add the terminating LF. Yuck.
*/
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);
}
/*
* Subclass of rerere_io that reads from an on-disk file
*/
struct rerere_io_file {
struct rerere_io io;
FILE *input;
};
/*
* ... and its getline() method implementation
*/
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');
}
/*
* Require the exact number of conflict marker letters, no more, no
* less, followed by SP or any whitespace
* (including LF).
*/
static int is_cmarker(char *buf, int marker_char, int marker_size)
{
int want_sp;
/*
* The beginning of our version and the end of their version
* always are labeled like "<<<<< ours" or ">>>>> theirs",
* hence we set want_sp for them. Note that the version from
* the common ancestor in diff3-style output is not always
* labelled (e.g. "||||| common" is often seen but "|||||"
* alone is also valid), so we do not set want_sp.
*/
want_sp = (marker_char == '<') || (marker_char == '>');
while (marker_size--)
if (*buf++ != marker_char)
return 0;
if (want_sp && *buf != ' ')
return 0;
return isspace(*buf);
}
/*
* Read contents a file with conflicts, normalize the conflicts
* by (1) discarding the common ancestor version in diff3-style,
* (2) reordering our side and their side so that whichever sorts
* alphabetically earlier comes before the other one, while
* computing the "conflict ID", which is just an SHA-1 hash of
* one side of the conflict, NUL, the other side of the conflict,
* and NUL concatenated together.
*
* Return the number of conflict hunks found.
*
* NEEDSWORK: the logic and theory of operation behind this conflict
* normalization may deserve to be documented somewhere, perhaps in
* Documentation/technical/rerere.txt.
*/
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)) {
if (hunk != RR_CONTEXT)
goto bad;
hunk = RR_SIDE_1;
} else if (is_cmarker(buf.buf, '|', marker_size)) {
if (hunk != RR_SIDE_1)
goto bad;
hunk = RR_ORIGINAL;
} else if (is_cmarker(buf.buf, '=', marker_size)) {
if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
goto bad;
hunk = RR_SIDE_2;
} else if (is_cmarker(buf.buf, '>', marker_size)) {
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;
}
/*
* Scan the path for conflicts, do the "handle_path()" thing above, and
* return the number of conflict hunks found.
*/
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_errno("Failed to flush %s", path);
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;
}
/*
* Look at a cache entry at "i" and see if it is not conflicting,
* conflicting and we are willing to handle, or conflicting and
* we are unable to handle, and return the determination in *type.
* Return the cache index to be looked at next, by skipping the
* stages we have already looked at in this invocation of this
* function.
*/
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;
while (ce_stage(active_cache[i]) == 1)
i++;
/* 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;
}
/*
* Scan the index and find paths that have conflicts that rerere can
* handle, i.e. the ones that has both stages #2 and #3.
*
* NEEDSWORK: we do not record or replay a previous "resolve by
* deletion" for a delete-modify conflict, as that is inherently risky
* without knowing what modification is being discarded. The only
* safe case, i.e. both side doing the deletion and modification that
* are identical to the previous round, might want to be handled,
* though.
*/
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;
}
/*
* The merge_rr list is meant to hold outstanding conflicted paths
* that rerere could handle. Abuse the list by adding other types of
* entries to allow the caller to show "rerere remaining".
*
* - Conflicted paths that rerere does not handle are added
* - Conflicted paths that have been resolved are marked as such
* by storing RERERE_RESOLVED to .util field (where conflict ID
* is expected to be stored).
*
* Do *not* write MERGE_RR file out after calling this function.
*
* NEEDSWORK: we may want to fix the caller that implements "rerere
* remaining" to do this without abusing merge_rr.
*/
int rerere_remaining(struct string_list *merge_rr)
{
int i;
if (setup_rerere(merge_rr, RERERE_READONLY))
return 0;
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_rerere_id(it);
it->util = RERERE_RESOLVED;
}
}
}
return 0;
}
/*
* Try using the given conflict resolution "ID" to see
* if that recorded conflict resolves cleanly what we
* got in the "cur".
*/
static int try_merge(const struct rerere_id *id, const char *path,
mmfile_t *cur, mmbuffer_t *result)
{
int ret;
mmfile_t base = {NULL, 0}, other = {NULL, 0};
if (read_mmfile(&base, rerere_path(id, "preimage")) ||
read_mmfile(&other, rerere_path(id, "postimage")))
ret = 1;
else
/*
* A three-way merge. Note that this honors user-customizable
* low-level merge driver settings.
*/
ret = ll_merge(result, path, &base, NULL, cur, "", &other, "", NULL);
free(base.ptr);
free(other.ptr);
return ret;
}
/*
* Find the conflict identified by "id"; the change between its
* "preimage" (i.e. a previous contents with conflict markers) and its
* "postimage" (i.e. the corresponding contents with conflicts
* resolved) may apply cleanly to the contents stored in "path", i.e.
* the conflict this time around.
*
* Returns 0 for successful replay of recorded resolution, or non-zero
* for failure.
*/
static int merge(const struct rerere_id *id, const char *path)
{
FILE *f;
int ret;
mmfile_t cur = {NULL, 0};
mmbuffer_t result = {NULL, 0};
/*
* Normalize the conflicts in path and write it out to
* "thisimage" temporary file.
*/
if ((handle_file(path, NULL, rerere_path(id, "thisimage")) < 0) ||
read_mmfile(&cur, rerere_path(id, "thisimage"))) {
ret = 1;
goto out;
}
ret = try_merge(id, path, &cur, &result);
if (ret)
goto out;
/*
* A successful replay of recorded resolution.
* Mark that "postimage" was used to help gc.
*/
if (utime(rerere_path(id, "postimage"), NULL) < 0)
warning_errno("failed utime() on %s",
rerere_path(id, "postimage"));
/* Update "path" with the resolution */
f = fopen(path, "w");
if (!f)
return error_errno("Could not open %s", path);
if (fwrite(result.ptr, result.size, 1, f) != 1)
error_errno("Could not write %s", path);
if (fclose(f))
return error_errno("Writing %s failed", path);
out:
free(cur.ptr);
free(result.ptr);
return ret;
}
static struct lock_file index_lock;
static void update_paths(struct string_list *update)
{
int i;
hold_locked_index(&index_lock, LOCK_DIE_ON_ERROR);
for (i = 0; i < update->nr; i++) {
struct string_list_item *item = &update->items[i];
if (add_file_to_cache(item->string, 0))
exit(128);
fprintf(stderr, "Staged '%s' using previous resolution.\n",
item->string);
}
if (active_cache_changed) {
if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
die("Unable to write new index file");
} else
rollback_lock_file(&index_lock);
}
static void remove_variant(struct rerere_id *id)
{
unlink_or_warn(rerere_path(id, "postimage"));
unlink_or_warn(rerere_path(id, "preimage"));
id->collection->status[id->variant] = 0;
}
/*
* The path indicated by rr_item may still have conflict for which we
* have a recorded resolution, in which case replay it and optionally
* update it. Or it may have been resolved by the user and we may
* only have the preimage for that conflict, in which case the result
* needs to be recorded as a resolution in a postimage file.
*/
static void do_rerere_one_path(struct string_list_item *rr_item,
struct string_list *update)
{
const char *path = rr_item->string;
struct rerere_id *id = rr_item->util;
struct rerere_dir *rr_dir = id->collection;
int variant;
variant = id->variant;
/* Has the user resolved it already? */
if (variant >= 0) {
if (!handle_file(path, NULL, NULL)) {
copy_file(rerere_path(id, "postimage"), path, 0666);
id->collection->status[variant] |= RR_HAS_POSTIMAGE;
fprintf(stderr, "Recorded resolution for '%s'.\n", path);
free_rerere_id(rr_item);
rr_item->util = NULL;
return;
}
/*
* There may be other variants that can cleanly
* replay. Try them and update the variant number for
* this one.
*/
}
/* Does any existing resolution apply cleanly? */
for (variant = 0; variant < rr_dir->status_nr; variant++) {
const int both = RR_HAS_PREIMAGE | RR_HAS_POSTIMAGE;
struct rerere_id vid = *id;
if ((rr_dir->status[variant] & both) != both)
continue;
vid.variant = variant;
if (merge(&vid, path))
continue; /* failed to replay */
/*
* If there already is a different variant that applies
* cleanly, there is no point maintaining our own variant.
*/
if (0 <= id->variant && id->variant != variant)
remove_variant(id);
if (rerere_autoupdate)
string_list_insert(update, path);
else
fprintf(stderr,
"Resolved '%s' using previous resolution.\n",
path);
free_rerere_id(rr_item);
rr_item->util = NULL;
return;
}
/* None of the existing one applies; we need a new variant */
assign_variant(id);
variant = id->variant;
handle_file(path, NULL, rerere_path(id, "preimage"));
if (id->collection->status[variant] & RR_HAS_POSTIMAGE) {
const char *path = rerere_path(id, "postimage");
if (unlink(path))
die_errno("cannot unlink stray '%s'", path);
id->collection->status[variant] &= ~RR_HAS_POSTIMAGE;
}
id->collection->status[variant] |= RR_HAS_PREIMAGE;
fprintf(stderr, "Recorded preimage for '%s'\n", path);
}
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++) {
struct rerere_id *id;
unsigned char sha1[20];
const char *path = conflict.items[i].string;
int ret;
if (string_list_has_string(rr, path))
continue;
/*
* Ask handle_file() to scan and assign a
* conflict ID. No need to write anything out
* yet.
*/
ret = handle_file(path, sha1, NULL);
if (ret < 1)
continue;
id = new_rerere_id(sha1);
string_list_insert(rr, path)->util = id;
/* Ensure that the directory exists. */
mkdir_in_gitdir(rerere_path(id, NULL));
}
for (i = 0; i < rr->nr; i++)
do_rerere_one_path(&rr->items[i], &update);
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 GIT_PATH_FUNC(git_path_rr_cache, "rr-cache")
static int is_rerere_enabled(void)
{
int rr_cache_exists;
if (!rerere_enabled)
return 0;
rr_cache_exists = is_directory(git_path_rr_cache());
if (rerere_enabled < 0)
return rr_cache_exists;
if (!rr_cache_exists && mkdir_in_gitdir(git_path_rr_cache()))
die("Could not create directory %s", git_path_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);
if (flags & RERERE_READONLY)
fd = 0;
else
fd = hold_lock_file_for_update(&write_lock, git_path_merge_rr(),
LOCK_DIE_ON_ERROR);
read_rr(merge_rr);
return fd;
}
/*
* The main entry point that is called internally from codepaths that
* perform mergy operations, possibly leaving conflicted index entries
* and working tree files.
*/
int rerere(int flags)
{
struct string_list merge_rr = STRING_LIST_INIT_DUP;
int fd, status;
fd = setup_rerere(&merge_rr, flags);
if (fd < 0)
return 0;
status = do_plain_rerere(&merge_rr, fd);
free_rerere_dirs();
return status;
}
/*
* Subclass of rerere_io that reads from an in-core buffer that is a
* strbuf
*/
struct rerere_io_mem {
struct rerere_io io;
struct strbuf input;
};
/*
* ... and its getline() method implementation
*/
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;
while (pos < active_nr) {
enum object_type type;
unsigned long size;
ce = active_cache[pos++];
if (ce_namelen(ce) != len || memcmp(ce->name, path, len))
break;
i = ce_stage(ce) - 1;
if (!mmfile[i].ptr) {
mmfile[i].ptr = read_sha1_file(ce->oid.hash, &type,
&size);
mmfile[i].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);
/*
* Grab the conflict ID and optionally write the original
* contents with conflict markers out.
*/
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 rerere_forget_one_path(const char *path, struct string_list *rr)
{
const char *filename;
struct rerere_id *id;
unsigned char sha1[20];
int ret;
struct string_list_item *item;
/*
* Recreate the original conflict from the stages in the
* index and compute the conflict ID
*/
ret = handle_cache(path, sha1, NULL);
if (ret < 1)
return error("Could not parse conflict hunks in '%s'", path);
/* Nuke the recorded resolution for the conflict */
id = new_rerere_id(sha1);
for (id->variant = 0;
id->variant < id->collection->status_nr;
id->variant++) {
mmfile_t cur = { NULL, 0 };
mmbuffer_t result = {NULL, 0};
int cleanly_resolved;
if (!has_rerere_resolution(id))
continue;
handle_cache(path, sha1, rerere_path(id, "thisimage"));
if (read_mmfile(&cur, rerere_path(id, "thisimage"))) {
free(cur.ptr);
error("Failed to update conflicted state in '%s'", path);
goto fail_exit;
}
cleanly_resolved = !try_merge(id, path, &cur, &result);
free(result.ptr);
free(cur.ptr);
if (cleanly_resolved)
break;
}
if (id->collection->status_nr <= id->variant) {
error("no remembered resolution for '%s'", path);
goto fail_exit;
}
filename = rerere_path(id, "postimage");
if (unlink(filename)) {
if (errno == ENOENT)
error("no remembered resolution for %s", path);
else
error_errno("cannot unlink %s", filename);
goto fail_exit;
}
/*
* Update the preimage so that the user can resolve the
* conflict in the working tree, run us again to record
* the postimage.
*/
handle_cache(path, sha1, rerere_path(id, "preimage"));
fprintf(stderr, "Updated preimage for '%s'\n", path);
/*
* And remember that we can record resolution for this
* conflict when the user is done.
*/
item = string_list_insert(rr, path);
free_rerere_id(item);
item->util = id;
fprintf(stderr, "Forgot resolution for %s\n", path);
return 0;
fail_exit:
free(id);
return -1;
}
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);
if (fd < 0)
return 0;
/*
* The paths may have been resolved (incorrectly);
* recover the original conflicted state and then
* find the conflicted paths.
*/
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);
}
/*
* Garbage collection support
*/
static time_t rerere_created_at(struct rerere_id *id)
{
struct stat st;
return stat(rerere_path(id, "preimage"), &st) ? (time_t) 0 : st.st_mtime;
}
static time_t rerere_last_used_at(struct rerere_id *id)
{
struct stat st;
return stat(rerere_path(id, "postimage"), &st) ? (time_t) 0 : st.st_mtime;
}
/*
* Remove the recorded resolution for a given conflict ID
*/
static void unlink_rr_item(struct rerere_id *id)
{
unlink_or_warn(rerere_path(id, "thisimage"));
remove_variant(id);
id->collection->status[id->variant] = 0;
}
static void prune_one(struct rerere_id *id, time_t now,
int cutoff_resolve, int cutoff_noresolve)
{
time_t then;
int cutoff;
then = rerere_last_used_at(id);
if (then)
cutoff = cutoff_resolve;
else {
then = rerere_created_at(id);
if (!then)
return;
cutoff = cutoff_noresolve;
}
if (then < now - cutoff * 86400)
unlink_rr_item(id);
}
void rerere_gc(struct string_list *rr)
{
struct string_list to_remove = STRING_LIST_INIT_DUP;
DIR *dir;
struct dirent *e;
int i;
time_t now = time(NULL);
int cutoff_noresolve = 15;
int cutoff_resolve = 60;
if (setup_rerere(rr, 0) < 0)
return;
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");
/* Collect stale conflict IDs ... */
while ((e = readdir(dir))) {
struct rerere_dir *rr_dir;
struct rerere_id id;
int now_empty;
if (is_dot_or_dotdot(e->d_name))
continue;
rr_dir = find_rerere_dir(e->d_name);
if (!rr_dir)
continue; /* or should we remove e->d_name? */
now_empty = 1;
for (id.variant = 0, id.collection = rr_dir;
id.variant < id.collection->status_nr;
id.variant++) {
prune_one(&id, now, cutoff_resolve, cutoff_noresolve);
if (id.collection->status[id.variant])
now_empty = 0;
}
if (now_empty)
string_list_append(&to_remove, e->d_name);
}
closedir(dir);
/* ... and then remove the empty directories */
for (i = 0; i < to_remove.nr; i++)
rmdir(git_path("rr-cache/%s", to_remove.items[i].string));
string_list_clear(&to_remove, 0);
rollback_lock_file(&write_lock);
}
/*
* During a conflict resolution, after "rerere" recorded the
* preimages, abandon them if the user did not resolve them or
* record their resolutions. And drop $GIT_DIR/MERGE_RR.
*
* NEEDSWORK: shouldn't we be calling this from "reset --hard"?
*/
void rerere_clear(struct string_list *merge_rr)
{
int i;
if (setup_rerere(merge_rr, 0) < 0)
return;
for (i = 0; i < merge_rr->nr; i++) {
struct rerere_id *id = merge_rr->items[i].util;
if (!has_rerere_resolution(id)) {
unlink_rr_item(id);
rmdir(rerere_path(id, NULL));
}
}
unlink_or_warn(git_path_merge_rr());
rollback_lock_file(&write_lock);
}