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-rw-r--r--rerere.c606
1 files changed, 606 insertions, 0 deletions
diff --git a/rerere.c b/rerere.c
new file mode 100644
index 0000000..d03a696
--- /dev/null
+++ b/rerere.c
@@ -0,0 +1,606 @@
+#include "cache.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"
+
+/* 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(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_addstr(&one, buf.buf);
+ else if (hunk == RR_ORIGINAL)
+ ; /* discard */
+ else if (hunk == RR_SIDE_2)
+ strbuf_addstr(&two, buf.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 = strchrnul(io->input.buf, '\n');
+ 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];
+ mmbuffer_t result = {NULL, 0};
+ 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;
+
+ mmfile[i].size = 0;
+ mmfile[i].ptr = NULL;
+ if (active_nr <= pos)
+ break;
+ ce = active_cache[pos++];
+ if (ce_namelen(ce) != len || memcmp(ce->name, path, len)
+ || ce_stage(ce) != i + 1)
+ break;
+ mmfile[i].ptr = read_sha1_file(ce->sha1, &type, &size);
+ mmfile[i].size = size;
+ }
+ for (i = 0; i < 3; i++) {
+ if (!mmfile[i].ptr && !mmfile[i].size)
+ mmfile[i].ptr = xstrdup("");
+ }
+ ll_merge(&result, path, &mmfile[0], NULL,
+ &mmfile[1], "ours",
+ &mmfile[2], "theirs", 0);
+ 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 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(conflict, (const char *)e2->name);
+ i++; /* skip over both #2 and #3 */
+ }
+ }
+ 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, "", 0);
+ 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));
+ }
+
+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_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(rr, path)->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(&update, path);
+ 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 flags)
+{
+ int fd;
+
+ git_config(git_rerere_config, NULL);
+ 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 = { NULL, 0, 0, 1 };
+ 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(const char **pathspec)
+{
+ int i, fd;
+ struct string_list conflict = { NULL, 0, 0, 1 };
+ struct string_list merge_rr = { NULL, 0, 0, 1 };
+
+ 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))
+ continue;
+ rerere_forget_one_path(it->string, &merge_rr);
+ }
+ return write_rr(&merge_rr, fd);
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-23 12:19:41 +0000