--- /dev/null
+#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;
+
+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;
+ write(out_fd, rr->items[i].util, 40);
+ write(out_fd, "\t", 1);
+ write(out_fd, path, strlen(path) + 1);
+ }
+ close(out_fd);
+ 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 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 (!strncmp("<<<<<<< ", buf, 8))
+ hunk = 1;
+ else if (!strncmp("=======", buf, 7))
+ hunk = 2;
+ else if (!strncmp(">>>>>>> ", buf, 8)) {
+ hunk_no++;
+ hunk = 0;
+ if (memcmp(one->ptr, two->ptr, one->nr < two->nr ?
+ one->nr : two->nr) > 0) {
+ 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);
+ }
+ } 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 + 2 < active_nr; i++) {
+ struct cache_entry *e1 = active_cache[i];
+ struct cache_entry *e2 = active_cache[i + 1];
+ struct cache_entry *e3 = active_cache[i + 2];
+ if (ce_stage(e1) == 1 && ce_stage(e2) == 2 &&
+ ce_stage(e3) == 3 && ce_same_name(e1, e2) &&
+ ce_same_name(e1, e3)) {
+ path_list_insert((const char *)e1->name, conflict);
+ i += 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++)
+ write(1, ptr[i].ptr, ptr[i].size);
+ 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;
+ xecfg.ctxlen = 3;
+ xecfg.flags = 0;
+ 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,
+ rr->nr - i - 1);
+ }
+ rr->nr--;
+ i--;
+ }
+
+ return write_rr(rr, fd);
+}
+
+int cmd_rerere(int argc, const char **argv, const char *prefix)
+{
+ struct path_list merge_rr = { NULL, 0, 0, 1 };
+ int i, fd = -1;
+ struct stat st;
+
+ if (stat(git_path("rr-cache"), &st) || !S_ISDIR(st.st_mode))
+ 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++) {
+ 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;
+}
+
--- /dev/null
+#!/bin/sh
+#
+# Copyright (c) 2006 Johannes E. Schindelin
+#
+
+test_description='git-rerere
+'
+
+. ./test-lib.sh
+
+cat > a1 << EOF
+Whether 'tis nobler in the mind to suffer
+The slings and arrows of outrageous fortune,
+Or to take arms against a sea of troubles,
+And by opposing end them? To die: to sleep;
+No more; and by a sleep to say we end
+The heart-ache and the thousand natural shocks
+That flesh is heir to, 'tis a consummation
+Devoutly to be wish'd.
+EOF
+
+git add a1
+git commit -q -a -m initial
+
+git checkout -b first
+cat >> a1 << EOF
+To die, to sleep;
+To sleep: perchance to dream: ay, there's the rub;
+For in that sleep of death what dreams may come
+When we have shuffled off this mortal coil,
+Must give us pause: there's the respect
+That makes calamity of so long life;
+EOF
+git commit -q -a -m first
+
+git checkout -b second master
+git show first:a1 | sed 's/To die, t/To die! T/' > a1
+git commit -q -a -m second
+
+# activate rerere
+mkdir .git/rr-cache
+
+test_expect_failure 'conflicting merge' 'git pull . first'
+
+sha1=4f58849a60b4f969a2848966b6d02893b783e8fb
+rr=.git/rr-cache/$sha1
+test_expect_success 'recorded preimage' "grep ======= $rr/preimage"
+
+test_expect_success 'no postimage or thisimage yet' \
+ "test ! -f $rr/postimage -a ! -f $rr/thisimage"
+
+git show first:a1 > a1
+
+cat > expect << EOF
+--- a/a1
++++ b/a1
+@@ -6,11 +6,7 @@
+ The heart-ache and the thousand natural shocks
+ That flesh is heir to, 'tis a consummation
+ Devoutly to be wish'd.
+-<<<<<<<
+-To die! To sleep;
+-=======
+ To die, to sleep;
+->>>>>>>
+ To sleep: perchance to dream: ay, there's the rub;
+ For in that sleep of death what dreams may come
+ When we have shuffled off this mortal coil,
+EOF
+
+git rerere diff > out
+
+test_expect_success 'rerere diff' 'diff -u expect out'
+
+cat > expect << EOF
+a1
+EOF
+
+git rerere status > out
+
+test_expect_success 'rerere status' 'diff -u expect out'
+
+test_expect_success 'commit succeeds' \
+ "git commit -q -a -m 'prefer first over second'"
+
+test_expect_success 'recorded postimage' "test -f $rr/postimage"
+
+git checkout -b third master
+git show second^:a1 | sed 's/To die: t/To die! T/' > a1
+git commit -q -a -m third
+
+test_expect_failure 'another conflicting merge' 'git pull . first'
+
+git show first:a1 | sed 's/To die: t/To die! T/' > expect
+test_expect_success 'rerere kicked in' "! grep ======= a1"
+
+test_expect_success 'rerere prefers first change' 'diff -u a1 expect'
+
+rm $rr/postimage
+echo "$sha1 a1" | tr '\012' '\0' > .git/rr-cache/MERGE_RR
+
+test_expect_success 'rerere clear' 'git rerere clear'
+
+test_expect_success 'clear removed the directory' "test ! -d $rr"
+
+mkdir $rr
+echo Hello > $rr/preimage
+echo World > $rr/postimage
+
+sha2=4000000000000000000000000000000000000000
+rr2=.git/rr-cache/$sha2
+mkdir $rr2
+echo Hello > $rr2/preimage
+
+case "$(date -d @11111111 +%s 2>/dev/null)" in
+[1-9]*)
+ # it is a recent GNU date. good.
+ now=$(date +%s)
+ almost_15_days_ago=$(($now+60-15*86400))
+ just_over_15_days_ago=$(($now-1-15*86400))
+ almost_60_days_ago=$(($now+60-60*86400))
+ just_over_60_days_ago=$(($now-1-60*86400))
+ predate1="$(date -d "@$almost_60_days_ago" +%c)"
+ predate2="$(date -d "@$almost_15_days_ago" +%c)"
+ postdate1="$(date -d "@$just_over_60_days_ago" +%c)"
+ postdate2="$(date -d "@$just_over_15_days_ago" +%c)"
+ ;;
+*)
+ # it is not GNU date. oh, well.
+ predate1="$(date)"
+ predate2="$(date)"
+ postdate1='1 Oct 2006 00:00:00'
+ postdate2='1 Dec 2006 00:00:00'
+esac
+
+touch -m -d "$predate1" $rr/preimage
+touch -m -d "$predate2" $rr2/preimage
+
+test_expect_success 'garbage collection (part1)' 'git rerere gc'
+
+test_expect_success 'young records still live' \
+ "test -f $rr/preimage -a -f $rr2/preimage"
+
+touch -m -d "$postdate1" $rr/preimage
+touch -m -d "$postdate2" $rr2/preimage
+
+test_expect_success 'garbage collection (part2)' 'git rerere gc'
+
+test_expect_success 'old records rest in peace' \
+ "test ! -f $rr/preimage -a ! -f $rr2/preimage"
+
+test_done
+
+