diff options
Diffstat (limited to 'rerere.c')
| -rw-r--r-- | rerere.c | 394 |
1 files changed, 394 insertions, 0 deletions
diff --git a/rerere.c b/rerere.c new file mode 100644 index 0000000000..713c6e16ac --- /dev/null +++ b/rerere.c @@ -0,0 +1,394 @@ +#include "cache.h" +#include "string-list.h" +#include "rerere.h" +#include "xdiff/xdiff.h" +#include "xdiff-interface.h" + +/* 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); +} + +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) && (buf[i] = fgetc(in)); i++) + ; /* do nothing */ + if (i == sizeof(buf)) + die("filename too long"); + string_list_insert(buf, rr)->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_in_full(out_fd, "\t", 1) != 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); +} + +static int handle_file(const char *path, + unsigned char *sha1, const char *output) +{ + git_SHA_CTX ctx; + char buf[1024]; + 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; + FILE *f = fopen(path, "r"); + FILE *out = NULL; + int wrerror = 0; + + if (!f) + return error("Could not open %s", path); + + if (output) { + out = fopen(output, "w"); + if (!out) { + fclose(f); + return error("Could not write %s", output); + } + } + + if (sha1) + git_SHA1_Init(&ctx); + + while (fgets(buf, sizeof(buf), f)) { + if (!prefixcmp(buf, "<<<<<<< ")) { + if (hunk != RR_CONTEXT) + goto bad; + hunk = RR_SIDE_1; + } else if (!prefixcmp(buf, "|||||||") && isspace(buf[7])) { + if (hunk != RR_SIDE_1) + goto bad; + hunk = RR_ORIGINAL; + } else if (!prefixcmp(buf, "=======") && isspace(buf[7])) { + if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL) + goto bad; + hunk = RR_SIDE_2; + } else if (!prefixcmp(buf, ">>>>>>> ")) { + if (hunk != RR_SIDE_2) + goto bad; + if (strbuf_cmp(&one, &two) > 0) + strbuf_swap(&one, &two); + hunk_no++; + hunk = RR_CONTEXT; + if (out) { + ferr_puts("<<<<<<<\n", out, &wrerror); + ferr_write(one.buf, one.len, out, &wrerror); + ferr_puts("=======\n", out, &wrerror); + ferr_write(two.buf, two.len, out, &wrerror); + ferr_puts(">>>>>>>\n", out, &wrerror); + } + 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_addstr(&one, buf); + else if (hunk == RR_ORIGINAL) + ; /* discard */ + else if (hunk == RR_SIDE_2) + strbuf_addstr(&two, buf); + else if (out) + ferr_puts(buf, out, &wrerror); + continue; + bad: + hunk = 99; /* force error exit */ + break; + } + strbuf_release(&one); + strbuf_release(&two); + + fclose(f); + if (wrerror) + error("There were errors while writing %s (%s)", + path, strerror(wrerror)); + if (out && fclose(out)) + wrerror = error("Failed to flush %s: %s", + path, strerror(errno)); + if (sha1) + git_SHA1_Final(sha1, &ctx); + if (hunk != RR_CONTEXT) { + if (output) + unlink(output); + return error("Could not parse conflict hunks in %s", path); + } + if (wrerror) + return -1; + return hunk_no; +} + +static int find_conflict(struct string_list *conflict) +{ + int i; + if (read_cache() < 0) + return error("Could not read index"); + for (i = 0; i+1 < active_nr; i++) { + struct cache_entry *e2 = active_cache[i]; + struct cache_entry *e3 = active_cache[i+1]; + if (ce_stage(e2) == 2 && + ce_stage(e3) == 3 && + ce_same_name(e2, e3) && + S_ISREG(e2->ce_mode) && + S_ISREG(e3->ce_mode)) { + string_list_insert((const char *)e2->name, conflict); + i++; /* skip over both #2 and #3 */ + } + } + return 0; +} + +static int merge(const char *name, const char *path) +{ + int ret; + mmfile_t cur, base, other; + mmbuffer_t result = {NULL, 0}; + xpparam_t xpp = {XDF_NEED_MINIMAL}; + + 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"))) + return 1; + ret = xdl_merge(&base, &cur, "", &other, "", + &xpp, XDL_MERGE_ZEALOUS, &result); + if (!ret) { + FILE *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)); + } + + 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_cache(fd, active_cache, active_nr) || + commit_locked_index(&index_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 = { NULL, 0, 0, 1 }; + struct string_list update = { NULL, 0, 0, 1 }; + 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(path, rr)->util = hex; + if (mkdir(git_path("rr-cache/%s", hex), 0755)) + 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)) { + if (rerere_autoupdate) + string_list_insert(path, &update); + fprintf(stderr, + "%s '%s' using previous resolution.\n", + rerere_autoupdate + ? "Staged" : "Resolved", + 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 int git_rerere_config(const char *var, const char *value, void *cb) +{ + if (!strcmp(var, "rerere.enabled")) + rerere_enabled = git_config_bool(var, value); + else if (!strcmp(var, "rerere.autoupdate")) + rerere_autoupdate = git_config_bool(var, value); + else + return git_default_config(var, value, cb); + return 0; +} + +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(rr_cache, 0777) || adjust_shared_perm(rr_cache))) + die("Could not create directory %s", rr_cache); + return 1; +} + +int setup_rerere(struct string_list *merge_rr) +{ + int fd; + + git_config(git_rerere_config, NULL); + if (!is_rerere_enabled()) + return -1; + + 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(void) +{ + struct string_list merge_rr = { NULL, 0, 0, 1 }; + int fd; + + fd = setup_rerere(&merge_rr); + if (fd < 0) + return 0; + return do_plain_rerere(&merge_rr, fd); +} |