diff options
Diffstat (limited to 'builtin-rerere.c')
| -rw-r--r-- | builtin-rerere.c | 459 |
1 files changed, 459 insertions, 0 deletions
diff --git a/builtin-rerere.c b/builtin-rerere.c new file mode 100644 index 0000000000..29d057c98c --- /dev/null +++ b/builtin-rerere.c @@ -0,0 +1,459 @@ +#include "builtin.h" +#include "cache.h" +#include "path-list.h" +#include "xdiff/xdiff.h" +#include "xdiff-interface.h" + +#include <time.h> + +static const char git_rerere_usage[] = +"git-rerere [clear | status | diff | gc]"; + +/* these values are days */ +static int cutoff_noresolve = 15; +static int cutoff_resolve = 60; + +/* if rerere_enabled == -1, fall back to detection of .git/rr-cache */ +static int rerere_enabled = -1; + +static char *merge_rr_path; + +static const char *rr_path(const char *name, const char *file) +{ + return git_path("rr-cache/%s/%s", name, file); +} + +static void read_rr(struct path_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"); + path_list_insert(buf, rr)->util = xstrdup(name); + } + fclose(in); +} + +static struct lock_file write_lock; + +static int write_rr(struct path_list *rr, int out_fd) +{ + int i; + for (i = 0; i < rr->nr; i++) { + const char *path = rr->items[i].path; + int 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 (close(out_fd) != 0) + die("unable to write rerere record"); + return commit_lock_file(&write_lock); +} + +struct buffer { + char *ptr; + int nr, alloc; +}; + +static void append_line(struct buffer *buffer, const char *line) +{ + int len = strlen(line); + + if (buffer->nr + len > buffer->alloc) { + buffer->alloc = alloc_nr(buffer->nr + len); + buffer->ptr = xrealloc(buffer->ptr, buffer->alloc); + } + memcpy(buffer->ptr + buffer->nr, line, len); + buffer->nr += len; +} + +static void clear_buffer(struct buffer *buffer) +{ + free(buffer->ptr); + buffer->ptr = NULL; + buffer->nr = buffer->alloc = 0; +} + +static int handle_file(const char *path, + unsigned char *sha1, const char *output) +{ + SHA_CTX ctx; + char buf[1024]; + int hunk = 0, hunk_no = 0; + struct buffer minus = { NULL, 0, 0 }, plus = { NULL, 0, 0 }; + struct buffer *one = &minus, *two = + + FILE *f = fopen(path, "r"); + FILE *out; + + 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); + } + } else + out = NULL; + + if (sha1) + SHA1_Init(&ctx); + + while (fgets(buf, sizeof(buf), f)) { + if (!prefixcmp(buf, "<<<<<<< ")) + hunk = 1; + else if (!prefixcmp(buf, "=======")) + hunk = 2; + else if (!prefixcmp(buf, ">>>>>>> ")) { + int one_is_longer = (one->nr > two->nr); + int common_len = one_is_longer ? two->nr : one->nr; + int cmp = memcmp(one->ptr, two->ptr, common_len); + + hunk_no++; + hunk = 0; + if ((cmp > 0) || ((cmp == 0) && one_is_longer)) { + struct buffer *swap = one; + one = two; + two = swap; + } + if (out) { + fputs("<<<<<<<\n", out); + fwrite(one->ptr, one->nr, 1, out); + fputs("=======\n", out); + fwrite(two->ptr, two->nr, 1, out); + fputs(">>>>>>>\n", out); + } + if (sha1) { + SHA1_Update(&ctx, one->ptr, one->nr); + SHA1_Update(&ctx, "\0", 1); + SHA1_Update(&ctx, two->ptr, two->nr); + SHA1_Update(&ctx, "\0", 1); + } + clear_buffer(one); + clear_buffer(two); + } else if (hunk == 1) + append_line(one, buf); + else if (hunk == 2) + append_line(two, buf); + else if (out) + fputs(buf, out); + } + + fclose(f); + if (out) + fclose(out); + if (sha1) + SHA1_Final(sha1, &ctx); + return hunk_no; +} + +static int find_conflict(struct path_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(ntohl(e2->ce_mode)) && + S_ISREG(ntohl(e3->ce_mode))) { + path_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, rr_path(name, "thisimage")) < 0) + return 1; + + if (read_mmfile(&cur, rr_path(name, "thisimage")) || + read_mmfile(&base, rr_path(name, "preimage")) || + read_mmfile(&other, rr_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 write to %s", path); + fwrite(result.ptr, result.size, 1, f); + fclose(f); + } + + free(cur.ptr); + free(base.ptr); + free(other.ptr); + free(result.ptr); + + return ret; +} + +static void unlink_rr_item(const char *name) +{ + unlink(rr_path(name, "thisimage")); + unlink(rr_path(name, "preimage")); + unlink(rr_path(name, "postimage")); + rmdir(git_path("rr-cache/%s", name)); +} + +static void garbage_collect(struct path_list *rr) +{ + struct path_list to_remove = { NULL, 0, 0, 1 }; + char buf[1024]; + DIR *dir; + struct dirent *e; + int len, i, cutoff; + time_t now = time(NULL), then; + + strlcpy(buf, git_path("rr-cache"), sizeof(buf)); + len = strlen(buf); + dir = opendir(buf); + strcpy(buf + len++, "/"); + while ((e = readdir(dir))) { + const char *name = e->d_name; + struct stat st; + if (name[0] == '.' && (name[1] == '\0' || + (name[1] == '.' && name[2] == '\0'))) + continue; + i = snprintf(buf + len, sizeof(buf) - len, "%s", name); + strlcpy(buf + len + i, "/preimage", sizeof(buf) - len - i); + if (stat(buf, &st)) + continue; + then = st.st_mtime; + strlcpy(buf + len + i, "/postimage", sizeof(buf) - len - i); + cutoff = stat(buf, &st) ? cutoff_noresolve : cutoff_resolve; + if (then < now - cutoff * 86400) { + buf[len + i] = '\0'; + path_list_insert(xstrdup(name), &to_remove); + } + } + for (i = 0; i < to_remove.nr; i++) + unlink_rr_item(to_remove.items[i].path); + path_list_clear(&to_remove, 0); +} + +static int outf(void *dummy, mmbuffer_t *ptr, int nbuf) +{ + int i; + for (i = 0; i < nbuf; i++) + if (write_in_full(1, ptr[i].ptr, ptr[i].size) != ptr[i].size) + return -1; + return 0; +} + +static int diff_two(const char *file1, const char *label1, + const char *file2, const char *label2) +{ + xpparam_t xpp; + xdemitconf_t xecfg; + xdemitcb_t ecb; + mmfile_t minus, plus; + + if (read_mmfile(&minus, file1) || read_mmfile(&plus, file2)) + return 1; + + printf("--- a/%s\n+++ b/%s\n", label1, label2); + fflush(stdout); + xpp.flags = XDF_NEED_MINIMAL; + memset(&xecfg, 0, sizeof(xecfg)); + xecfg.ctxlen = 3; + ecb.outf = outf; + xdl_diff(&minus, &plus, &xpp, &xecfg, &ecb); + + free(minus.ptr); + free(plus.ptr); + return 0; +} + +static int copy_file(const char *src, const char *dest) +{ + FILE *in, *out; + char buffer[32768]; + int count; + + if (!(in = fopen(src, "r"))) + return error("Could not open %s", src); + if (!(out = fopen(dest, "w"))) + return error("Could not open %s", dest); + while ((count = fread(buffer, 1, sizeof(buffer), in))) + fwrite(buffer, 1, count, out); + fclose(in); + fclose(out); + return 0; +} + +static int do_plain_rerere(struct path_list *rr, int fd) +{ + struct path_list conflict = { 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].path; + if (!path_list_has_path(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)); + path_list_insert(path, rr)->util = hex; + if (mkdir(git_path("rr-cache/%s", hex), 0755)) + continue;; + handle_file(path, NULL, rr_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++) { + struct stat st; + int ret; + const char *path = rr->items[i].path; + const char *name = (const char *)rr->items[i].util; + + if (!stat(rr_path(name, "preimage"), &st) && + !stat(rr_path(name, "postimage"), &st)) { + if (!merge(name, path)) { + fprintf(stderr, "Resolved '%s' using " + "previous resolution.\n", path); + goto tail_optimization; + } + } + + /* 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(path, rr_path(name, "postimage")); +tail_optimization: + if (i < rr->nr - 1) + memmove(rr->items + i, + rr->items + i + 1, + sizeof(rr->items[0]) * (rr->nr - i - 1)); + rr->nr--; + i--; + } + + return write_rr(rr, fd); +} + +static int git_rerere_config(const char *var, const char *value) +{ + if (!strcmp(var, "gc.rerereresolved")) + cutoff_resolve = git_config_int(var, value); + else if (!strcmp(var, "gc.rerereunresolved")) + cutoff_noresolve = git_config_int(var, value); + else if (!strcmp(var, "rerere.enabled")) + rerere_enabled = git_config_bool(var, value); + else + return git_default_config(var, value); + return 0; +} + +static int is_rerere_enabled(void) +{ + struct stat st; + const char *rr_cache; + int rr_cache_exists; + + if (!rerere_enabled) + return 0; + + rr_cache = git_path("rr-cache"); + rr_cache_exists = !stat(rr_cache, &st) && S_ISDIR(st.st_mode); + 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 cmd_rerere(int argc, const char **argv, const char *prefix) +{ + struct path_list merge_rr = { NULL, 0, 0, 1 }; + int i, fd = -1; + + git_config(git_rerere_config); + if (!is_rerere_enabled()) + return 0; + + merge_rr_path = xstrdup(git_path("rr-cache/MERGE_RR")); + fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 1); + read_rr(&merge_rr); + + if (argc < 2) + return do_plain_rerere(&merge_rr, fd); + else if (!strcmp(argv[1], "clear")) { + for (i = 0; i < merge_rr.nr; i++) { + struct stat st; + const char *name = (const char *)merge_rr.items[i].util; + if (!stat(git_path("rr-cache/%s", name), &st) && + S_ISDIR(st.st_mode) && + stat(rr_path(name, "postimage"), &st)) + unlink_rr_item(name); + } + unlink(merge_rr_path); + } else if (!strcmp(argv[1], "gc")) + garbage_collect(&merge_rr); + else if (!strcmp(argv[1], "status")) + for (i = 0; i < merge_rr.nr; i++) + printf("%s\n", merge_rr.items[i].path); + else if (!strcmp(argv[1], "diff")) + for (i = 0; i < merge_rr.nr; i++) { + const char *path = merge_rr.items[i].path; + const char *name = (const char *)merge_rr.items[i].util; + diff_two(rr_path(name, "preimage"), path, path, path); + } + else + usage(git_rerere_usage); + + path_list_clear(&merge_rr, 1); + return 0; +} |