rerere: use "struct rerere_id" instead of "char *" for conflict ID

This gives a thin abstraction between the conflict ID that is a hash
value obtained by inspecting the conflicts and the name of the
directory under $GIT_DIR/rr-cache/, in which the previous resolution
is recorded to be replayed.  The plan is to make sure that the
presence of the directory does not imply the presense of a previous
resolution and vice-versa, and later allow us to have more than one
pair of <preimage, postimage> for a given conflict ID.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/rerere.c b/builtin/rerere.c
index 81730bb5e677cbb1c622984d8b518ca4b6bfa611..fd229a7c7dae54be4285ba4d9528fb4d1aae2b74 100644 (file)
--- a/builtin/rerere.c
+++ b/builtin/rerere.c
@@ -103,7 +103,7 @@ int cmd_rerere(int argc, const char **argv, const char *prefix)
        } else if (!strcmp(argv[0], "diff"))
                for (i = 0; i < merge_rr.nr; i++) {
                        const char *path = merge_rr.items[i].string;
-                       const char *id = (const char *)merge_rr.items[i].util;
+                       const struct rerere_id *id = merge_rr.items[i].util;
                        diff_two(rerere_path(id, "preimage"), path, path, path);
                }
        else

diff --git a/rerere.c b/rerere.c
index 2865aeaf704e5987939647ccdca39af66bf89a2e..93fdeec809c44cab70c7ac439c9f13ce2d1f3d46 100644 (file)
--- a/rerere.c
+++ b/rerere.c
@@ -22,17 +22,43 @@ static int rerere_autoupdate;
 
 static char *merge_rr_path;
 
-const char *rerere_path(const char *id, const char *file)
+static void free_rerere_id(struct string_list_item *item)
 {
-       return git_path("rr-cache/%s/%s", id, file);
+       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 char *id)
+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));
+       strcpy(id->hex, 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
@@ -50,6 +76,7 @@ static void read_rr(struct string_list *rr)
        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))
@@ -59,8 +86,8 @@ static void read_rr(struct string_list *rr)
                        die("corrupt MERGE_RR");
                buf.buf[40] = '\0';
                path = buf.buf + 41;
-
-               string_list_insert(rr, path)->util = xstrdup(buf.buf);
+               id = new_rerere_id_hex(buf.buf);
+               string_list_insert(rr, path)->util = id;
        }
        strbuf_release(&buf);
        fclose(in);
@@ -73,12 +100,15 @@ 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);
-               if (!rr->items[i].util)
+
+               id = rr->items[i].util;
+               if (!id)
                        continue;
                strbuf_addf(&buf, "%s\t%s%c",
-                           (char *)rr->items[i].util,
+                           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");
@@ -530,7 +560,7 @@ int rerere_remaining(struct string_list *merge_rr)
                        struct string_list_item *it;
                        it = string_list_lookup(merge_rr, (const char *)e->name);
                        if (it != NULL) {
-                               free(it->util);
+                               free_rerere_id(it);
                                it->util = RERERE_RESOLVED;
                        }
                }
@@ -548,7 +578,7 @@ int rerere_remaining(struct string_list *merge_rr)
  * Returns 0 for successful replay of recorded resolution, or non-zero
  * for failure.
  */
-static int merge(const char *id, const char *path)
+static int merge(const struct rerere_id *id, const char *path)
 {
        int ret;
        mmfile_t cur = {NULL, 0}, base = {NULL, 0}, other = {NULL, 0};
@@ -582,8 +612,8 @@ static int merge(const char *id, const char *path)
                 */
                if (utime(rerere_path(id, "postimage"), NULL) < 0)
                        warning("failed utime() on %s: %s",
-                                       rerere_path(id, "postimage"),
-                                       strerror(errno));
+                               rerere_path(id, "postimage"),
+                               strerror(errno));
 
                /* Update "path" with the resolution */
                f = fopen(path, "w");
@@ -640,7 +670,7 @@ static void do_rerere_one_path(struct string_list_item *rr_item,
                               struct string_list *update)
 {
        const char *path = rr_item->string;
-       const char *id = (const char *)rr_item->util;
+       const struct rerere_id *id = rr_item->util;
 
        /* Is there a recorded resolution we could attempt to apply? */
        if (has_rerere_resolution(id)) {
@@ -660,7 +690,7 @@ static void do_rerere_one_path(struct string_list_item *rr_item,
        } else {
                return;
        }
-       free(rr_item->util);
+       free_rerere_id(rr_item);
        rr_item->util = NULL;
 }
 
@@ -679,10 +709,10 @@ static int do_plain_rerere(struct string_list *rr, int fd)
         * initial run would catch all and register their preimages.
         */
        for (i = 0; i < conflict.nr; i++) {
+               struct rerere_id *id;
                unsigned char sha1[20];
-               char *id;
-               int ret;
                const char *path = conflict.items[i].string;
+               int ret;
 
                if (string_list_has_string(rr, path))
                        continue;
@@ -695,7 +725,8 @@ static int do_plain_rerere(struct string_list *rr, int fd)
                ret = handle_file(path, sha1, NULL);
                if (ret < 1)
                        continue;
-               id = xstrdup(sha1_to_hex(sha1));
+
+               id = new_rerere_id(sha1);
                string_list_insert(rr, path)->util = id;
 
                /*
@@ -706,7 +737,7 @@ static int do_plain_rerere(struct string_list *rr, int fd)
                 * NEEDSWORK: make sure "gc" does not remove
                 * preimage without removing the directory.
                 */
-               if (mkdir_in_gitdir(git_path("rr-cache/%s", id)))
+               if (mkdir_in_gitdir(rerere_path(id, NULL)))
                        continue;
 
                /*
@@ -788,7 +819,7 @@ int rerere(int flags)
 static int rerere_forget_one_path(const char *path, struct string_list *rr)
 {
        const char *filename;
-       char *id;
+       struct rerere_id *id;
        unsigned char sha1[20];
        int ret;
        struct string_list_item *item;
@@ -802,7 +833,7 @@ static int rerere_forget_one_path(const char *path, struct string_list *rr)
                return error("Could not parse conflict hunks in '%s'", path);
 
        /* Nuke the recorded resolution for the conflict */
-       id = xstrdup(sha1_to_hex(sha1));
+       id = new_rerere_id(sha1);
        filename = rerere_path(id, "postimage");
        if (unlink(filename))
                return (errno == ENOENT
@@ -822,7 +853,7 @@ static int rerere_forget_one_path(const char *path, struct string_list *rr)
         * conflict when the user is done.
         */
        item = string_list_insert(rr, path);
-       free(item->util);
+       free_rerere_id(item);
        item->util = id;
        fprintf(stderr, "Forgot resolution for %s\n", path);
        return 0;
@@ -859,22 +890,38 @@ int rerere_forget(struct pathspec *pathspec)
 /*
  * Garbage collection support
  */
-static time_t rerere_created_at(const char *id)
+
+/*
+ * 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;
+       strcpy(id.hex, 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 *id)
+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(const char *id)
+static void unlink_rr_item(struct rerere_id *id)
 {
        unlink(rerere_path(id, "thisimage"));
        unlink(rerere_path(id, "preimage"));
@@ -884,7 +931,7 @@ static void unlink_rr_item(const char *id)
         * assume that we already have preimage recorded in
         * do_plain_rerere()?
         */
-       rmdir(git_path("rr-cache/%s", id));
+       rmdir(rerere_path(id, NULL));
 }
 
 void rerere_gc(struct string_list *rr)
@@ -923,7 +970,7 @@ void rerere_gc(struct string_list *rr)
        closedir(dir);
        /* ... and then remove them one-by-one */
        for (i = 0; i < to_remove.nr; i++)
-               unlink_rr_item(to_remove.items[i].string);
+               unlink_rr_item(dirname_to_id(to_remove.items[i].string));
        string_list_clear(&to_remove, 0);
 }
 
@@ -939,7 +986,7 @@ void rerere_clear(struct string_list *merge_rr)
        int i;
 
        for (i = 0; i < merge_rr->nr; i++) {
-               const char *id = (const char *)merge_rr->items[i].util;
+               struct rerere_id *id = merge_rr->items[i].util;
                if (!has_rerere_resolution(id))
                        unlink_rr_item(id);
        }

diff --git a/rerere.h b/rerere.h
index f998ebae6e18ca55edac7f5e724b22c116e42ed9..ce545d0c045b3df6f2ab723638fe7df081aadf30 100644 (file)
--- a/rerere.h
+++ b/rerere.h
@@ -15,9 +15,19 @@ struct pathspec;
  */
 extern void *RERERE_RESOLVED;
 
+struct rerere_id {
+       char hex[41];
+};
+
 extern int setup_rerere(struct string_list *, int);
 extern int rerere(int);
-extern const char *rerere_path(const char *id, const char *file);
+/*
+ * Given the conflict ID and the name of a "file" used for replaying
+ * the recorded resolution (e.g. "preimage", "postimage"), return the
+ * path to that filesystem entity.  With "file" specified with NULL,
+ * return the path to the directory that houses these files.
+ */
+extern const char *rerere_path(const struct rerere_id *, const char *file);
 extern int rerere_forget(struct pathspec *);
 extern int rerere_remaining(struct string_list *);
 extern void rerere_clear(struct string_list *);