diff options
Diffstat (limited to 'third_party/git/rerere.c')
| -rw-r--r-- | third_party/git/rerere.c | 1255 |
1 files changed, 1255 insertions, 0 deletions
diff --git a/third_party/git/rerere.c b/third_party/git/rerere.c new file mode 100644 index 000000000000..9281131a9f10 --- /dev/null +++ b/third_party/git/rerere.c @@ -0,0 +1,1255 @@ +#include "cache.h" +#include "config.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 "object-store.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 hash[GIT_MAX_HEXSZ]; + 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_AND_NULL(rerere_dir); + rerere_dir_nr = rerere_dir_alloc = 0; +} + +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 hash_to_hex(id->collection->hash); +} + +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", hash_to_hex(rr_dir->hash))); + + 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_hash(size_t i, void *table) +{ + struct rerere_dir **rr_dir = table; + return rr_dir[i]->hash; +} + +static struct rerere_dir *find_rerere_dir(const char *hex) +{ + unsigned char hash[GIT_MAX_RAWSZ]; + struct rerere_dir *rr_dir; + int pos; + + if (get_sha1_hex(hex, hash)) + return NULL; /* BUG */ + pos = sha1_pos(hash, rerere_dir, rerere_dir_nr, rerere_dir_hash); + if (pos < 0) { + rr_dir = xmalloc(sizeof(*rr_dir)); + hashcpy(rr_dir->hash, hash); + 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++; + MOVE_ARRAY(rerere_dir + pos + 1, rerere_dir + pos, + rerere_dir_nr - pos - 1); + 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 *hash) +{ + return new_rerere_id_hex(hash_to_hex(hash)); +} + +/* + * $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 repository *r, struct string_list *rr) +{ + struct strbuf buf = STRBUF_INIT; + FILE *in = fopen_or_warn(git_path_merge_rr(r), "r"); + + if (!in) + return; + while (!strbuf_getwholeline(&buf, in, '\0')) { + char *path; + unsigned char hash[GIT_MAX_RAWSZ]; + struct rerere_id *id; + int variant; + const unsigned hexsz = the_hash_algo->hexsz; + + /* There has to be the hash, tab, path and then NUL */ + if (buf.len < hexsz + 2 || get_sha1_hex(buf.buf, hash)) + die(_("corrupt MERGE_RR")); + + if (buf.buf[hexsz] != '.') { + variant = 0; + path = buf.buf + hexsz; + } else { + errno = 0; + variant = strtol(buf.buf + hexsz + 1, &path, 10); + if (errno) + die(_("corrupt MERGE_RR")); + } + if (*(path++) != '\t') + die(_("corrupt MERGE_RR")); + buf.buf[hexsz] = '\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) < 0) + 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); +} + +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); +} + +static void rerere_strbuf_putconflict(struct strbuf *buf, int ch, size_t size) +{ + strbuf_addchars(buf, ch, size); + strbuf_addch(buf, '\n'); +} + +static int handle_conflict(struct strbuf *out, struct rerere_io *io, + int marker_size, git_hash_ctx *ctx) +{ + enum { + RR_SIDE_1 = 0, RR_SIDE_2, RR_ORIGINAL + } hunk = RR_SIDE_1; + struct strbuf one = STRBUF_INIT, two = STRBUF_INIT; + struct strbuf buf = STRBUF_INIT, conflict = STRBUF_INIT; + int has_conflicts = -1; + + while (!io->getline(&buf, io)) { + if (is_cmarker(buf.buf, '<', marker_size)) { + if (handle_conflict(&conflict, io, marker_size, NULL) < 0) + break; + if (hunk == RR_SIDE_1) + strbuf_addbuf(&one, &conflict); + else + strbuf_addbuf(&two, &conflict); + strbuf_release(&conflict); + } else if (is_cmarker(buf.buf, '|', marker_size)) { + if (hunk != RR_SIDE_1) + break; + hunk = RR_ORIGINAL; + } else if (is_cmarker(buf.buf, '=', marker_size)) { + if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL) + break; + hunk = RR_SIDE_2; + } else if (is_cmarker(buf.buf, '>', marker_size)) { + if (hunk != RR_SIDE_2) + break; + if (strbuf_cmp(&one, &two) > 0) + strbuf_swap(&one, &two); + has_conflicts = 1; + rerere_strbuf_putconflict(out, '<', marker_size); + strbuf_addbuf(out, &one); + rerere_strbuf_putconflict(out, '=', marker_size); + strbuf_addbuf(out, &two); + rerere_strbuf_putconflict(out, '>', marker_size); + if (ctx) { + the_hash_algo->update_fn(ctx, one.buf ? + one.buf : "", + one.len + 1); + the_hash_algo->update_fn(ctx, two.buf ? + two.buf : "", + two.len + 1); + } + break; + } 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); + } + strbuf_release(&one); + strbuf_release(&two); + strbuf_release(&buf); + + return has_conflicts; +} + +/* + * 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 1 if conflict hunks are found, 0 if there are no conflict + * hunks and -1 if an error occurred. + */ +static int handle_path(unsigned char *hash, struct rerere_io *io, int marker_size) +{ + git_hash_ctx ctx; + struct strbuf buf = STRBUF_INIT, out = STRBUF_INIT; + int has_conflicts = 0; + if (hash) + the_hash_algo->init_fn(&ctx); + + while (!io->getline(&buf, io)) { + if (is_cmarker(buf.buf, '<', marker_size)) { + has_conflicts = handle_conflict(&out, io, marker_size, + hash ? &ctx : NULL); + if (has_conflicts < 0) + break; + rerere_io_putmem(out.buf, out.len, io); + strbuf_reset(&out); + } else + rerere_io_putstr(buf.buf, io); + } + strbuf_release(&buf); + strbuf_release(&out); + + if (hash) + the_hash_algo->final_fn(hash, &ctx); + + return has_conflicts; +} + +/* + * Scan the path for conflicts, do the "handle_path()" thing above, and + * return the number of conflict hunks found. + */ +static int handle_file(struct index_state *istate, + const char *path, unsigned char *hash, const char *output) +{ + int has_conflicts = 0; + struct rerere_io_file io; + int marker_size = ll_merge_marker_size(istate, 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_errno(_("could not open '%s'"), path); + + if (output) { + io.io.output = fopen(output, "w"); + if (!io.io.output) { + error_errno(_("could not write '%s'"), output); + fclose(io.input); + return -1; + } + } + + has_conflicts = handle_path(hash, (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 (has_conflicts < 0) { + if (output) + unlink_or_warn(output); + return error(_("could not parse conflict hunks in '%s'"), path); + } + if (io.io.wrerror) + return -1; + return has_conflicts; +} + +/* + * 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(struct index_state *istate, int i, int *type) +{ + const struct cache_entry *e = istate->cache[i]; + + if (!ce_stage(e)) { + *type = RESOLVED; + return i + 1; + } + + *type = PUNTED; + while (i < istate->cache_nr && ce_stage(istate->cache[i]) == 1) + i++; + + /* Only handle regular files with both stages #2 and #3 */ + if (i + 1 < istate->cache_nr) { + const struct cache_entry *e2 = istate->cache[i]; + const struct cache_entry *e3 = istate->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 < istate->cache_nr && ce_same_name(e, istate->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 repository *r, struct string_list *conflict) +{ + int i; + + if (repo_read_index(r) < 0) + return error(_("index file corrupt")); + + for (i = 0; i < r->index->cache_nr;) { + int conflict_type; + const struct cache_entry *e = r->index->cache[i]; + i = check_one_conflict(r->index, 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 repository *r, struct string_list *merge_rr) +{ + int i; + + if (setup_rerere(r, merge_rr, RERERE_READONLY)) + return 0; + if (repo_read_index(r) < 0) + return error(_("index file corrupt")); + + for (i = 0; i < r->index->cache_nr;) { + int conflict_type; + const struct cache_entry *e = r->index->cache[i]; + i = check_one_conflict(r->index, 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(struct index_state *istate, + 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, "", + istate, 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(struct index_state *istate, 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(istate, path, NULL, rerere_path(id, "thisimage")) < 0) || + read_mmfile(&cur, rerere_path(id, "thisimage"))) { + ret = 1; + goto out; + } + + ret = try_merge(istate, 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 void update_paths(struct repository *r, struct string_list *update) +{ + struct lock_file index_lock = LOCK_INIT; + int i; + + repo_hold_locked_index(r, &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_index(r->index, item->string, 0)) + exit(128); + fprintf_ln(stderr, _("Staged '%s' using previous resolution."), + item->string); + } + + if (write_locked_index(r->index, &index_lock, + COMMIT_LOCK | SKIP_IF_UNCHANGED)) + die(_("unable to write new index file")); +} + +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 index_state *istate, + 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(istate, path, NULL, NULL)) { + copy_file(rerere_path(id, "postimage"), path, 0666); + id->collection->status[variant] |= RR_HAS_POSTIMAGE; + fprintf_ln(stderr, _("Recorded resolution for '%s'."), 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(istate, &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_ln(stderr, + _("Resolved '%s' using previous resolution."), + 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(istate, 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_ln(stderr, _("Recorded preimage for '%s'"), path); +} + +static int do_plain_rerere(struct repository *r, + 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(r, &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 hash[GIT_MAX_RAWSZ]; + const char *path = conflict.items[i].string; + int ret; + + /* + * Ask handle_file() to scan and assign a + * conflict ID. No need to write anything out + * yet. + */ + ret = handle_file(r->index, path, hash, NULL); + if (ret != 0 && string_list_has_string(rr, path)) { + remove_variant(string_list_lookup(rr, path)->util); + string_list_remove(rr, path, 1); + } + if (ret < 1) + continue; + + id = new_rerere_id(hash); + 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(r->index, &rr->items[i], &update); + + if (update.nr) + update_paths(r, &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 repository *r, 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(r), + LOCK_DIE_ON_ERROR); + read_rr(r, 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 repo_rerere(struct repository *r, int flags) +{ + struct string_list merge_rr = STRING_LIST_INIT_DUP; + int fd, status; + + fd = setup_rerere(r, &merge_rr, flags); + if (fd < 0) + return 0; + status = do_plain_rerere(r, &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(struct index_state *istate, + const char *path, unsigned char *hash, const char *output) +{ + mmfile_t mmfile[3] = {{NULL}}; + mmbuffer_t result = {NULL, 0}; + const struct cache_entry *ce; + int pos, len, i, has_conflicts; + struct rerere_io_mem io; + int marker_size = ll_merge_marker_size(istate, path); + + /* + * Reproduce the conflicted merge in-core + */ + len = strlen(path); + pos = index_name_pos(istate, path, len); + if (0 <= pos) + return -1; + pos = -pos - 1; + + while (pos < istate->cache_nr) { + enum object_type type; + unsigned long size; + + ce = istate->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_object_file(&ce->oid, &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", + istate, 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. + */ + has_conflicts = handle_path(hash, (struct rerere_io *)&io, marker_size); + strbuf_release(&io.input); + if (io.io.output) + fclose(io.io.output); + return has_conflicts; +} + +static int rerere_forget_one_path(struct index_state *istate, + const char *path, + struct string_list *rr) +{ + const char *filename; + struct rerere_id *id; + unsigned char hash[GIT_MAX_RAWSZ]; + 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(istate, path, hash, 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(hash); + + 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(istate, path, hash, 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(istate, 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(istate, path, hash, rerere_path(id, "preimage")); + fprintf_ln(stderr, _("Updated preimage for '%s'"), 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 repository *r, struct pathspec *pathspec) +{ + int i, fd; + struct string_list conflict = STRING_LIST_INIT_DUP; + struct string_list merge_rr = STRING_LIST_INIT_DUP; + + if (repo_read_index(r) < 0) + return error(_("index file corrupt")); + + fd = setup_rerere(r, &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_index(r->index, pathspec); + find_conflict(r, &conflict); + for (i = 0; i < conflict.nr; i++) { + struct string_list_item *it = &conflict.items[i]; + if (!match_pathspec(r->index, pathspec, it->string, + strlen(it->string), 0, NULL, 0)) + continue; + rerere_forget_one_path(r->index, it->string, &merge_rr); + } + return write_rr(&merge_rr, fd); +} + +/* + * Garbage collection support + */ + +static timestamp_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 timestamp_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, + timestamp_t cutoff_resolve, timestamp_t cutoff_noresolve) +{ + timestamp_t then; + timestamp_t 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 < cutoff) + unlink_rr_item(id); +} + +void rerere_gc(struct repository *r, struct string_list *rr) +{ + struct string_list to_remove = STRING_LIST_INIT_DUP; + DIR *dir; + struct dirent *e; + int i; + timestamp_t now = time(NULL); + timestamp_t cutoff_noresolve = now - 15 * 86400; + timestamp_t cutoff_resolve = now - 60 * 86400; + + if (setup_rerere(r, rr, 0) < 0) + return; + + git_config_get_expiry_in_days("gc.rerereresolved", &cutoff_resolve, now); + git_config_get_expiry_in_days("gc.rerereunresolved", &cutoff_noresolve, now); + 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, 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 repository *r, struct string_list *merge_rr) +{ + int i; + + if (setup_rerere(r, 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(r)); + rollback_lock_file(&write_lock); +} |