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-rw-r--r--rerere.c1008
1 files changed, 1008 insertions, 0 deletions
diff --git a/rerere.c b/rerere.c
new file mode 100644
index 0000000..587b7e2
--- /dev/null
+++ b/rerere.c
@@ -0,0 +1,1008 @@
+#include "cache.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"
+
+#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 void free_rerere_id(struct string_list_item *item)
+{
+ free(item->util);
+}
+
+static const char *rerere_id_hex(const struct rerere_id *id)
+{
+ return id->hex;
+}
+
+const char *rerere_path(const struct rerere_id *id, const char *file)
+{
+ if (!file)
+ return git_path("rr-cache/%s", rerere_id_hex(id));
+
+ return git_path("rr-cache/%s/%s", rerere_id_hex(id), file);
+}
+
+static int has_rerere_resolution(const struct rerere_id *id)
+{
+ struct stat st;
+
+ return !stat(rerere_path(id, "postimage"), &st);
+}
+
+static struct rerere_id *new_rerere_id_hex(char *hex)
+{
+ struct rerere_id *id = xmalloc(sizeof(*id));
+ xsnprintf(id->hex, sizeof(id->hex), "%s", hex);
+ return id;
+}
+
+static struct rerere_id *new_rerere_id(unsigned char *sha1)
+{
+ return new_rerere_id_hex(sha1_to_hex(sha1));
+}
+
+/*
+ * $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 string_list *rr)
+{
+ struct strbuf buf = STRBUF_INIT;
+ FILE *in = fopen(git_path_merge_rr(), "r");
+
+ if (!in)
+ return;
+ while (!strbuf_getwholeline(&buf, in, '\0')) {
+ char *path;
+ unsigned char sha1[20];
+ struct rerere_id *id;
+
+ /* There has to be the hash, tab, path and then NUL */
+ if (buf.len < 42 || get_sha1_hex(buf.buf, sha1))
+ die("corrupt MERGE_RR");
+
+ if (buf.buf[40] != '\t')
+ die("corrupt MERGE_RR");
+ buf.buf[40] = '\0';
+ path = buf.buf + 41;
+ id = new_rerere_id_hex(buf.buf);
+ 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;
+ 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) != buf.len)
+ 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);
+}
+
+/*
+ * Write a conflict marker to io->output (if defined).
+ */
+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;
+
+ /*
+ * Make sure we will not write everything out
+ * in this round by leaving at least 1 byte
+ * for the next round, giving the next round
+ * a chance to add the terminating LF. Yuck.
+ */
+ 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);
+}
+
+/*
+ * 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);
+}
+
+/*
+ * 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 the number of conflict hunks found.
+ *
+ * NEEDSWORK: the logic and theory of operation behind this conflict
+ * normalization may deserve to be documented somewhere, perhaps in
+ * Documentation/technical/rerere.txt.
+ */
+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)) {
+ if (hunk != RR_CONTEXT)
+ goto bad;
+ hunk = RR_SIDE_1;
+ } else if (is_cmarker(buf.buf, '|', marker_size)) {
+ if (hunk != RR_SIDE_1)
+ goto bad;
+ hunk = RR_ORIGINAL;
+ } else if (is_cmarker(buf.buf, '=', marker_size)) {
+ if (hunk != RR_SIDE_1 && hunk != RR_ORIGINAL)
+ goto bad;
+ hunk = RR_SIDE_2;
+ } else if (is_cmarker(buf.buf, '>', marker_size)) {
+ 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_addbuf(&one, &buf);
+ else if (hunk == RR_ORIGINAL)
+ ; /* discard */
+ else if (hunk == RR_SIDE_2)
+ strbuf_addbuf(&two, &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;
+}
+
+/*
+ * Scan the path for conflicts, do the "handle_path()" thing above, and
+ * return the number of conflict hunks found.
+ */
+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;
+}
+
+/*
+ * 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(const char *path, unsigned char *sha1, const char *output)
+{
+ mmfile_t mmfile[3] = {{NULL}};
+ mmbuffer_t result = {NULL, 0};
+ const 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;
+
+ while (pos < active_nr) {
+ enum object_type type;
+ unsigned long size;
+
+ ce = active_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_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("");
+
+ /*
+ * NEEDSWORK: handle conflicts from merges with
+ * merge.renormalize set, too
+ */
+ ll_merge(&result, path, &mmfile[0], NULL,
+ &mmfile[1], "ours",
+ &mmfile[2], "theirs", 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.
+ */
+ 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;
+}
+
+/*
+ * 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(int i, int *type)
+{
+ const struct cache_entry *e = active_cache[i];
+
+ if (!ce_stage(e)) {
+ *type = RESOLVED;
+ return i + 1;
+ }
+
+ *type = PUNTED;
+ while (ce_stage(active_cache[i]) == 1)
+ i++;
+
+ /* Only handle regular files with both stages #2 and #3 */
+ if (i + 1 < active_nr) {
+ const struct cache_entry *e2 = active_cache[i];
+ const struct cache_entry *e3 = active_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 < active_nr && ce_same_name(e, active_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 string_list *conflict)
+{
+ int i;
+ if (read_cache() < 0)
+ return error("Could not read index");
+
+ for (i = 0; i < active_nr;) {
+ int conflict_type;
+ const struct cache_entry *e = active_cache[i];
+ i = check_one_conflict(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 string_list *merge_rr)
+{
+ int i;
+ if (setup_rerere(merge_rr, RERERE_READONLY))
+ return 0;
+ if (read_cache() < 0)
+ return error("Could not read index");
+
+ for (i = 0; i < active_nr;) {
+ int conflict_type;
+ const struct cache_entry *e = active_cache[i];
+ i = check_one_conflict(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;
+}
+
+/*
+ * 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(const struct rerere_id *id, const char *path)
+{
+ FILE *f;
+ int ret;
+ mmfile_t cur = {NULL, 0}, base = {NULL, 0}, other = {NULL, 0};
+ mmbuffer_t result = {NULL, 0};
+
+ /*
+ * Normalize the conflicts in path and write it out to
+ * "thisimage" temporary file.
+ */
+ if (handle_file(path, NULL, rerere_path(id, "thisimage")) < 0) {
+ ret = 1;
+ goto out;
+ }
+
+ if (read_mmfile(&cur, rerere_path(id, "thisimage")) ||
+ read_mmfile(&base, rerere_path(id, "preimage")) ||
+ read_mmfile(&other, rerere_path(id, "postimage"))) {
+ ret = 1;
+ goto out;
+ }
+
+ /*
+ * A three-way merge. Note that this honors user-customizable
+ * low-level merge driver settings.
+ */
+ ret = ll_merge(&result, path, &base, NULL, &cur, "", &other, "", NULL);
+ 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("failed utime() on %s: %s",
+ rerere_path(id, "postimage"),
+ strerror(errno));
+
+ /* Update "path" with the resolution */
+ 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 void update_paths(struct string_list *update)
+{
+ int i;
+
+ hold_locked_index(&index_lock, 1);
+
+ for (i = 0; i < update->nr; i++) {
+ struct string_list_item *item = &update->items[i];
+ if (add_file_to_cache(item->string, 0))
+ exit(128);
+ fprintf(stderr, "Staged '%s' using previous resolution.\n",
+ item->string);
+ }
+
+ if (active_cache_changed) {
+ if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
+ die("Unable to write new index file");
+ } else
+ rollback_lock_file(&index_lock);
+}
+
+/*
+ * 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 string_list_item *rr_item,
+ struct string_list *update)
+{
+ const char *path = rr_item->string;
+ const struct rerere_id *id = rr_item->util;
+
+ /* Is there a recorded resolution we could attempt to apply? */
+ if (has_rerere_resolution(id)) {
+ if (merge(id, path))
+ return; /* failed to replay */
+
+ if (rerere_autoupdate)
+ string_list_insert(update, path);
+ else
+ fprintf(stderr,
+ "Resolved '%s' using previous resolution.\n",
+ path);
+ } else if (!handle_file(path, NULL, NULL)) {
+ /* The user has resolved it. */
+ copy_file(rerere_path(id, "postimage"), path, 0666);
+ fprintf(stderr, "Recorded resolution for '%s'.\n", path);
+ } else {
+ return;
+ }
+ free_rerere_id(rr_item);
+ rr_item->util = NULL;
+}
+
+static int do_plain_rerere(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(&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 sha1[20];
+ const char *path = conflict.items[i].string;
+ int ret;
+
+ if (string_list_has_string(rr, path))
+ continue;
+
+ /*
+ * Ask handle_file() to scan and assign a
+ * conflict ID. No need to write anything out
+ * yet.
+ */
+ ret = handle_file(path, sha1, NULL);
+ if (ret < 1)
+ continue;
+
+ id = new_rerere_id(sha1);
+ string_list_insert(rr, path)->util = id;
+
+ /*
+ * If the directory does not exist, create
+ * it. mkdir_in_gitdir() will fail with
+ * EEXIST if there already is one.
+ *
+ * NEEDSWORK: make sure "gc" does not remove
+ * preimage without removing the directory.
+ */
+ if (mkdir_in_gitdir(rerere_path(id, NULL)))
+ continue;
+
+ /*
+ * We are the first to encounter this
+ * conflict. Ask handle_file() to write the
+ * normalized contents to the "preimage" file.
+ */
+ handle_file(path, NULL, rerere_path(id, "preimage"));
+ fprintf(stderr, "Recorded preimage for '%s'\n", path);
+ }
+
+ for (i = 0; i < rr->nr; i++)
+ do_rerere_one_path(&rr->items[i], &update);
+
+ if (update.nr)
+ update_paths(&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 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(),
+ LOCK_DIE_ON_ERROR);
+ read_rr(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 rerere(int flags)
+{
+ struct string_list merge_rr = STRING_LIST_INIT_DUP;
+ 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;
+ struct rerere_id *id;
+ unsigned char sha1[20];
+ 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(path, sha1, 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(sha1);
+ filename = rerere_path(id, "postimage");
+ if (unlink(filename))
+ return (errno == ENOENT
+ ? error("no remembered resolution for %s", path)
+ : error("cannot unlink %s: %s", filename, strerror(errno)));
+
+ /*
+ * Update the preimage so that the user can resolve the
+ * conflict in the working tree, run us again to record
+ * the postimage.
+ */
+ handle_cache(path, sha1, rerere_path(id, "preimage"));
+ fprintf(stderr, "Updated preimage for '%s'\n", 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;
+}
+
+int rerere_forget(struct pathspec *pathspec)
+{
+ int i, fd;
+ struct string_list conflict = STRING_LIST_INIT_DUP;
+ struct string_list merge_rr = STRING_LIST_INIT_DUP;
+
+ if (read_cache() < 0)
+ return error("Could not read index");
+
+ fd = setup_rerere(&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_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, 0))
+ continue;
+ rerere_forget_one_path(it->string, &merge_rr);
+ }
+ return write_rr(&merge_rr, fd);
+}
+
+/*
+ * Garbage collection support
+ */
+
+/*
+ * Note that this is not reentrant but is used only one-at-a-time
+ * so it does not matter right now.
+ */
+static struct rerere_id *dirname_to_id(const char *name)
+{
+ static struct rerere_id id;
+ xsnprintf(id.hex, sizeof(id.hex), "%s", name);
+ return &id;
+}
+
+static time_t rerere_created_at(const char *dir_name)
+{
+ struct stat st;
+ struct rerere_id *id = dirname_to_id(dir_name);
+
+ return stat(rerere_path(id, "preimage"), &st) ? (time_t) 0 : st.st_mtime;
+}
+
+static time_t rerere_last_used_at(const char *dir_name)
+{
+ struct stat st;
+ struct rerere_id *id = dirname_to_id(dir_name);
+
+ 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(rerere_path(id, "thisimage"));
+ unlink(rerere_path(id, "preimage"));
+ unlink(rerere_path(id, "postimage"));
+ /*
+ * NEEDSWORK: what if this rmdir() fails? Wouldn't we then
+ * assume that we already have preimage recorded in
+ * do_plain_rerere()?
+ */
+ rmdir(rerere_path(id, NULL));
+}
+
+void rerere_gc(struct string_list *rr)
+{
+ struct string_list to_remove = STRING_LIST_INIT_DUP;
+ DIR *dir;
+ struct dirent *e;
+ int i, cutoff;
+ time_t now = time(NULL), then;
+ int cutoff_noresolve = 15;
+ int cutoff_resolve = 60;
+
+ if (setup_rerere(rr, 0) < 0)
+ return;
+
+ git_config_get_int("gc.rerereresolved", &cutoff_resolve);
+ git_config_get_int("gc.rerereunresolved", &cutoff_noresolve);
+ 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))) {
+ if (is_dot_or_dotdot(e->d_name))
+ continue;
+
+ then = rerere_last_used_at(e->d_name);
+ if (then) {
+ cutoff = cutoff_resolve;
+ } else {
+ then = rerere_created_at(e->d_name);
+ if (!then)
+ continue;
+ cutoff = cutoff_noresolve;
+ }
+ if (then < now - cutoff * 86400)
+ string_list_append(&to_remove, e->d_name);
+ }
+ closedir(dir);
+ /* ... and then remove them one-by-one */
+ for (i = 0; i < to_remove.nr; i++)
+ unlink_rr_item(dirname_to_id(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 string_list *merge_rr)
+{
+ int i;
+
+ if (setup_rerere(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);
+ }
+ unlink_or_warn(git_path_merge_rr());
+ rollback_lock_file(&write_lock);
+}
generated by cgit v0.10.2-6-g49f6 at 2024-04-26 09:48:55 (GMT)