Merge branch 'bc/maint-apply-check-no-patch'
[gitweb.git] / refs.c
diff --git a/refs.c b/refs.c
index cbc4c5d28d3252a3336cfa370cb3d720d5d8556d..f5cb297292f5ae577e3d2719f5f78512aae8cf28 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -4,9 +4,8 @@
 #include "tag.h"
 #include "dir.h"
 
-/* ISSYMREF=01 and ISPACKED=02 are public interfaces */
-#define REF_KNOWS_PEELED 04
-#define REF_BROKEN 010
+/* ISSYMREF=0x01, ISPACKED=0x02 and ISBROKEN=0x04 are public interfaces */
+#define REF_KNOWS_PEELED 0x10
 
 struct ref_entry {
        unsigned char flag; /* ISSYMREF? ISPACKED? */
@@ -49,7 +48,7 @@ static const char *parse_ref_line(char *line, unsigned char *sha1)
 }
 
 static void add_ref(const char *name, const unsigned char *sha1,
-                   int flag, struct ref_array *refs,
+                   int flag, int check_name, struct ref_array *refs,
                    struct ref_entry **new_entry)
 {
        int len;
@@ -60,6 +59,9 @@ static void add_ref(const char *name, const unsigned char *sha1,
        entry = xmalloc(sizeof(struct ref_entry) + len);
        hashcpy(entry->sha1, sha1);
        hashclr(entry->peeled);
+       if (check_name &&
+           check_refname_format(name, REFNAME_ALLOW_ONELEVEL|REFNAME_DOT_COMPONENT))
+               die("Reference has invalid format: '%s'", name);
        memcpy(entry->name, name, len);
        entry->flag = flag;
        if (new_entry)
@@ -94,6 +96,7 @@ static void sort_ref_array(struct ref_array *array)
                                die("Duplicated ref, and SHA1s don't match: %s",
                                    a->name);
                        warning("Duplicated ref: %s", a->name);
+                       free(b);
                        continue;
                }
                i++;
@@ -131,12 +134,16 @@ static struct ref_entry *search_ref_array(struct ref_array *array, const char *n
  * Future: need to be in "struct repository"
  * when doing a full libification.
  */
-static struct cached_refs {
+static struct ref_cache {
+       struct ref_cache *next;
        char did_loose;
        char did_packed;
        struct ref_array loose;
        struct ref_array packed;
-} cached_refs, submodule_refs;
+       /* The submodule name, or "" for the main repo. */
+       char name[FLEX_ARRAY];
+} *ref_cache;
+
 static struct ref_entry *current_ref;
 
 static struct ref_array extra_refs;
@@ -151,18 +158,63 @@ static void free_ref_array(struct ref_array *array)
        array->refs = NULL;
 }
 
-static void invalidate_cached_refs(void)
+static void clear_packed_ref_cache(struct ref_cache *refs)
+{
+       if (refs->did_packed)
+               free_ref_array(&refs->packed);
+       refs->did_packed = 0;
+}
+
+static void clear_loose_ref_cache(struct ref_cache *refs)
 {
-       struct cached_refs *ca = &cached_refs;
+       if (refs->did_loose)
+               free_ref_array(&refs->loose);
+       refs->did_loose = 0;
+}
 
-       if (ca->did_loose)
-               free_ref_array(&ca->loose);
-       if (ca->did_packed)
-               free_ref_array(&ca->packed);
-       ca->did_loose = ca->did_packed = 0;
+static struct ref_cache *create_ref_cache(const char *submodule)
+{
+       int len;
+       struct ref_cache *refs;
+       if (!submodule)
+               submodule = "";
+       len = strlen(submodule) + 1;
+       refs = xcalloc(1, sizeof(struct ref_cache) + len);
+       memcpy(refs->name, submodule, len);
+       return refs;
+}
+
+/*
+ * Return a pointer to a ref_cache for the specified submodule. For
+ * the main repository, use submodule==NULL. The returned structure
+ * will be allocated and initialized but not necessarily populated; it
+ * should not be freed.
+ */
+static struct ref_cache *get_ref_cache(const char *submodule)
+{
+       struct ref_cache *refs = ref_cache;
+       if (!submodule)
+               submodule = "";
+       while (refs) {
+               if (!strcmp(submodule, refs->name))
+                       return refs;
+               refs = refs->next;
+       }
+
+       refs = create_ref_cache(submodule);
+       refs->next = ref_cache;
+       ref_cache = refs;
+       return refs;
+}
+
+void invalidate_ref_cache(const char *submodule)
+{
+       struct ref_cache *refs = get_ref_cache(submodule);
+       clear_packed_ref_cache(refs);
+       clear_loose_ref_cache(refs);
 }
 
-static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
+static void read_packed_refs(FILE *f, struct ref_array *array)
 {
        struct ref_entry *last = NULL;
        char refline[PATH_MAX];
@@ -183,7 +235,7 @@ static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
 
                name = parse_ref_line(refline, sha1);
                if (name) {
-                       add_ref(name, sha1, flag, &cached_refs->packed, &last);
+                       add_ref(name, sha1, flag, 1, array, &last);
                        continue;
                }
                if (last &&
@@ -193,12 +245,12 @@ static void read_packed_refs(FILE *f, struct cached_refs *cached_refs)
                    !get_sha1_hex(refline + 1, sha1))
                        hashcpy(last->peeled, sha1);
        }
-       sort_ref_array(&cached_refs->packed);
+       sort_ref_array(array);
 }
 
 void add_extra_ref(const char *name, const unsigned char *sha1, int flag)
 {
-       add_ref(name, sha1, flag, &extra_refs, NULL);
+       add_ref(name, sha1, flag, 0, &extra_refs, NULL);
 }
 
 void clear_extra_refs(void)
@@ -208,22 +260,19 @@ void clear_extra_refs(void)
 
 static struct ref_array *get_packed_refs(const char *submodule)
 {
-       const char *packed_refs_file;
-       struct cached_refs *refs;
+       struct ref_cache *refs = get_ref_cache(submodule);
 
-       if (submodule) {
-               packed_refs_file = git_path_submodule(submodule, "packed-refs");
-               refs = &submodule_refs;
-               free_ref_array(&refs->packed);
-       } else {
-               packed_refs_file = git_path("packed-refs");
-               refs = &cached_refs;
-       }
+       if (!refs->did_packed) {
+               const char *packed_refs_file;
+               FILE *f;
 
-       if (!refs->did_packed || submodule) {
-               FILE *f = fopen(packed_refs_file, "r");
+               if (submodule)
+                       packed_refs_file = git_path_submodule(submodule, "packed-refs");
+               else
+                       packed_refs_file = git_path("packed-refs");
+               f = fopen(packed_refs_file, "r");
                if (f) {
-                       read_packed_refs(f, refs);
+                       read_packed_refs(f, &refs->packed);
                        fclose(f);
                }
                refs->did_packed = 1;
@@ -283,14 +332,13 @@ static void get_ref_dir(const char *submodule, const char *base,
                                flag = 0;
                                if (resolve_gitlink_ref(submodule, ref, sha1) < 0) {
                                        hashclr(sha1);
-                                       flag |= REF_BROKEN;
+                                       flag |= REF_ISBROKEN;
                                }
-                       } else
-                               if (!resolve_ref(ref, sha1, 1, &flag)) {
-                                       hashclr(sha1);
-                                       flag |= REF_BROKEN;
-                               }
-                       add_ref(ref, sha1, flag, array, NULL);
+                       } else if (read_ref_full(ref, sha1, 1, &flag)) {
+                               hashclr(sha1);
+                               flag |= REF_ISBROKEN;
+                       }
+                       add_ref(ref, sha1, flag, 1, array, NULL);
                }
                free(ref);
                closedir(dir);
@@ -333,45 +381,41 @@ void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refname)
 
 static struct ref_array *get_loose_refs(const char *submodule)
 {
-       if (submodule) {
-               free_ref_array(&submodule_refs.loose);
-               get_ref_dir(submodule, "refs", &submodule_refs.loose);
-               sort_ref_array(&submodule_refs.loose);
-               return &submodule_refs.loose;
-       }
+       struct ref_cache *refs = get_ref_cache(submodule);
 
-       if (!cached_refs.did_loose) {
-               get_ref_dir(NULL, "refs", &cached_refs.loose);
-               sort_ref_array(&cached_refs.loose);
-               cached_refs.did_loose = 1;
+       if (!refs->did_loose) {
+               get_ref_dir(submodule, "refs", &refs->loose);
+               sort_ref_array(&refs->loose);
+               refs->did_loose = 1;
        }
-       return &cached_refs.loose;
+       return &refs->loose;
 }
 
 /* We allow "recursive" symbolic refs. Only within reason, though */
 #define MAXDEPTH 5
 #define MAXREFLEN (1024)
 
+/*
+ * Called by resolve_gitlink_ref_recursive() after it failed to read
+ * from "name", which is "module/.git/<refname>". Find <refname> in
+ * the packed-refs file for the submodule.
+ */
 static int resolve_gitlink_packed_ref(char *name, int pathlen, const char *refname, unsigned char *result)
 {
-       FILE *f;
-       struct cached_refs refs;
-       struct ref_entry *ref;
        int retval = -1;
-
-       strcpy(name + pathlen, "packed-refs");
-       f = fopen(name, "r");
-       if (!f)
-               return -1;
-       memset(&refs, 0, sizeof(refs));
-       read_packed_refs(f, &refs);
-       fclose(f);
-       ref = search_ref_array(&refs.packed, refname);
+       struct ref_entry *ref;
+       struct ref_array *array;
+
+       /* being defensive: resolve_gitlink_ref() did this for us */
+       if (pathlen < 6 || memcmp(name + pathlen - 6, "/.git/", 6))
+               die("Oops");
+       name[pathlen - 6] = '\0'; /* make it path to the submodule */
+       array = get_packed_refs(name);
+       ref = search_ref_array(array, refname);
        if (ref != NULL) {
                memcpy(result, ref->sha1, 20);
                retval = 0;
        }
-       free_ref_array(&refs.packed);
        return retval;
 }
 
@@ -424,7 +468,7 @@ int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *re
        memcpy(gitdir + len, "/.git", 6);
        len += 5;
 
-       tmp = read_gitfile_gently(gitdir);
+       tmp = read_gitfile(gitdir);
        if (tmp) {
                free(gitdir);
                len = strlen(tmp);
@@ -439,17 +483,20 @@ int resolve_gitlink_ref(const char *path, const char *refname, unsigned char *re
 }
 
 /*
- * If the "reading" argument is set, this function finds out what _object_
- * the ref points at by "reading" the ref.  The ref, if it is not symbolic,
- * has to exist, and if it is symbolic, it has to point at an existing ref,
- * because the "read" goes through the symref to the ref it points at.
- *
- * The access that is not "reading" may often be "writing", but does not
- * have to; it can be merely checking _where it leads to_. If it is a
- * prelude to "writing" to the ref, a write to a symref that points at
- * yet-to-be-born ref will create the real ref pointed by the symref.
- * reading=0 allows the caller to check where such a symref leads to.
+ * Try to read ref from the packed references.  On success, set sha1
+ * and return 0; otherwise, return -1.
  */
+static int get_packed_ref(const char *ref, unsigned char *sha1)
+{
+       struct ref_array *packed = get_packed_refs(NULL);
+       struct ref_entry *entry = search_ref_array(packed, ref);
+       if (entry) {
+               hashcpy(sha1, entry->sha1);
+               return 0;
+       }
+       return -1;
+}
+
 const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *flag)
 {
        int depth = MAXDEPTH;
@@ -460,6 +507,9 @@ const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *
        if (flag)
                *flag = 0;
 
+       if (check_refname_format(ref, REFNAME_ALLOW_ONELEVEL))
+               return NULL;
+
        for (;;) {
                char path[PATH_MAX];
                struct stat st;
@@ -470,27 +520,36 @@ const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *
                        return NULL;
 
                git_snpath(path, sizeof(path), "%s", ref);
-               /* Special case: non-existing file. */
+
                if (lstat(path, &st) < 0) {
-                       struct ref_array *packed = get_packed_refs(NULL);
-                       struct ref_entry *r = search_ref_array(packed, ref);
-                       if (r != NULL) {
-                               hashcpy(sha1, r->sha1);
+                       if (errno != ENOENT)
+                               return NULL;
+                       /*
+                        * The loose reference file does not exist;
+                        * check for a packed reference.
+                        */
+                       if (!get_packed_ref(ref, sha1)) {
                                if (flag)
                                        *flag |= REF_ISPACKED;
                                return ref;
                        }
-                       if (reading || errno != ENOENT)
+                       /* The reference is not a packed reference, either. */
+                       if (reading) {
                                return NULL;
-                       hashclr(sha1);
-                       return ref;
+                       } else {
+                               hashclr(sha1);
+                               return ref;
+                       }
                }
 
                /* Follow "normalized" - ie "refs/.." symlinks by hand */
                if (S_ISLNK(st.st_mode)) {
                        len = readlink(path, buffer, sizeof(buffer)-1);
-                       if (len >= 5 && !memcmp("refs/", buffer, 5)) {
-                               buffer[len] = 0;
+                       if (len < 0)
+                               return NULL;
+                       buffer[len] = 0;
+                       if (!prefixcmp(buffer, "refs/") &&
+                                       !check_refname_format(buffer, 0)) {
                                strcpy(ref_buffer, buffer);
                                ref = ref_buffer;
                                if (flag)
@@ -514,26 +573,35 @@ const char *resolve_ref(const char *ref, unsigned char *sha1, int reading, int *
                        return NULL;
                len = read_in_full(fd, buffer, sizeof(buffer)-1);
                close(fd);
+               if (len < 0)
+                       return NULL;
+               while (len && isspace(buffer[len-1]))
+                       len--;
+               buffer[len] = '\0';
 
                /*
                 * Is it a symbolic ref?
                 */
-               if (len < 4 || memcmp("ref:", buffer, 4))
+               if (prefixcmp(buffer, "ref:"))
                        break;
-               buf = buffer + 4;
-               len -= 4;
-               while (len && isspace(*buf))
-                       buf++, len--;
-               while (len && isspace(buf[len-1]))
-                       len--;
-               buf[len] = 0;
-               memcpy(ref_buffer, buf, len + 1);
-               ref = ref_buffer;
                if (flag)
                        *flag |= REF_ISSYMREF;
+               buf = buffer + 4;
+               while (isspace(*buf))
+                       buf++;
+               if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
+                       if (flag)
+                               *flag |= REF_ISBROKEN;
+                       return NULL;
+               }
+               ref = strcpy(ref_buffer, buf);
        }
-       if (len < 40 || get_sha1_hex(buffer, sha1))
+       /* Please note that FETCH_HEAD has a second line containing other data. */
+       if (get_sha1_hex(buffer, sha1) || (buffer[40] != '\0' && !isspace(buffer[40]))) {
+               if (flag)
+                       *flag |= REF_ISBROKEN;
                return NULL;
+       }
        return ref;
 }
 
@@ -544,23 +612,28 @@ struct ref_filter {
        void *cb_data;
 };
 
-int read_ref(const char *ref, unsigned char *sha1)
+int read_ref_full(const char *ref, unsigned char *sha1, int reading, int *flags)
 {
-       if (resolve_ref(ref, sha1, 1, NULL))
+       if (resolve_ref(ref, sha1, reading, flags))
                return 0;
        return -1;
 }
 
+int read_ref(const char *ref, unsigned char *sha1)
+{
+       return read_ref_full(ref, sha1, 1, NULL);
+}
+
 #define DO_FOR_EACH_INCLUDE_BROKEN 01
 static int do_one_ref(const char *base, each_ref_fn fn, int trim,
                      int flags, void *cb_data, struct ref_entry *entry)
 {
-       if (strncmp(base, entry->name, trim))
+       if (prefixcmp(entry->name, base))
                return 0;
 
        if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) {
-               if (entry->flag & REF_BROKEN)
-                       return 0; /* ignore dangling symref */
+               if (entry->flag & REF_ISBROKEN)
+                       return 0; /* ignore broken refs e.g. dangling symref */
                if (!has_sha1_file(entry->sha1)) {
                        error("%s does not point to a valid object!", entry->name);
                        return 0;
@@ -595,7 +668,7 @@ int peel_ref(const char *ref, unsigned char *sha1)
                goto fallback;
        }
 
-       if (!resolve_ref(ref, base, 1, &flag))
+       if (read_ref_full(ref, base, 1, &flag))
                return -1;
 
        if ((flag & REF_ISPACKED)) {
@@ -678,7 +751,7 @@ static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
                return 0;
        }
 
-       if (resolve_ref("HEAD", sha1, 1, &flag))
+       if (!read_ref_full("HEAD", sha1, 1, &flag))
                return fn("HEAD", sha1, flag, cb_data);
 
        return 0;
@@ -696,12 +769,12 @@ int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 
 int for_each_ref(each_ref_fn fn, void *cb_data)
 {
-       return do_for_each_ref(NULL, "refs/", fn, 0, 0, cb_data);
+       return do_for_each_ref(NULL, "", fn, 0, 0, cb_data);
 }
 
 int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data)
 {
-       return do_for_each_ref(submodule, "refs/", fn, 0, 0, cb_data);
+       return do_for_each_ref(submodule, "", fn, 0, 0, cb_data);
 }
 
 int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data)
@@ -750,6 +823,31 @@ int for_each_replace_ref(each_ref_fn fn, void *cb_data)
        return do_for_each_ref(NULL, "refs/replace/", fn, 13, 0, cb_data);
 }
 
+int head_ref_namespaced(each_ref_fn fn, void *cb_data)
+{
+       struct strbuf buf = STRBUF_INIT;
+       int ret = 0;
+       unsigned char sha1[20];
+       int flag;
+
+       strbuf_addf(&buf, "%sHEAD", get_git_namespace());
+       if (!read_ref_full(buf.buf, sha1, 1, &flag))
+               ret = fn(buf.buf, sha1, flag, cb_data);
+       strbuf_release(&buf);
+
+       return ret;
+}
+
+int for_each_namespaced_ref(each_ref_fn fn, void *cb_data)
+{
+       struct strbuf buf = STRBUF_INIT;
+       int ret;
+       strbuf_addf(&buf, "%srefs/", get_git_namespace());
+       ret = do_for_each_ref(NULL, buf.buf, fn, 0, 0, cb_data);
+       strbuf_release(&buf);
+       return ret;
+}
+
 int for_each_glob_ref_in(each_ref_fn fn, const char *pattern,
        const char *prefix, void *cb_data)
 {
@@ -787,7 +885,7 @@ int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data)
 
 int for_each_rawref(each_ref_fn fn, void *cb_data)
 {
-       return do_for_each_ref(NULL, "refs/", fn, 0,
+       return do_for_each_ref(NULL, "", fn, 0,
                               DO_FOR_EACH_INCLUDE_BROKEN, cb_data);
 }
 
@@ -803,70 +901,87 @@ int for_each_rawref(each_ref_fn fn, void *cb_data)
  * - it contains a "\" (backslash)
  */
 
+/* Return true iff ch is not allowed in reference names. */
 static inline int bad_ref_char(int ch)
 {
-       if (((unsigned) ch) <= ' ' ||
+       if (((unsigned) ch) <= ' ' || ch == 0x7f ||
            ch == '~' || ch == '^' || ch == ':' || ch == '\\')
                return 1;
        /* 2.13 Pattern Matching Notation */
-       if (ch == '?' || ch == '[') /* Unsupported */
+       if (ch == '*' || ch == '?' || ch == '[') /* Unsupported */
                return 1;
-       if (ch == '*') /* Supported at the end */
-               return 2;
        return 0;
 }
 
-int check_ref_format(const char *ref)
+/*
+ * Try to read one refname component from the front of ref.  Return
+ * the length of the component found, or -1 if the component is not
+ * legal.
+ */
+static int check_refname_component(const char *ref, int flags)
 {
-       int ch, level, bad_type, last;
-       int ret = CHECK_REF_FORMAT_OK;
-       const char *cp = ref;
-
-       level = 0;
-       while (1) {
-               while ((ch = *cp++) == '/')
-                       ; /* tolerate duplicated slashes */
-               if (!ch)
-                       /* should not end with slashes */
-                       return CHECK_REF_FORMAT_ERROR;
-
-               /* we are at the beginning of the path component */
-               if (ch == '.')
-                       return CHECK_REF_FORMAT_ERROR;
-               bad_type = bad_ref_char(ch);
-               if (bad_type) {
-                       if (bad_type == 2 && (!*cp || *cp == '/') &&
-                           ret == CHECK_REF_FORMAT_OK)
-                               ret = CHECK_REF_FORMAT_WILDCARD;
-                       else
-                               return CHECK_REF_FORMAT_ERROR;
-               }
+       const char *cp;
+       char last = '\0';
 
+       for (cp = ref; ; cp++) {
+               char ch = *cp;
+               if (ch == '\0' || ch == '/')
+                       break;
+               if (bad_ref_char(ch))
+                       return -1; /* Illegal character in refname. */
+               if (last == '.' && ch == '.')
+                       return -1; /* Refname contains "..". */
+               if (last == '@' && ch == '{')
+                       return -1; /* Refname contains "@{". */
                last = ch;
-               /* scan the rest of the path component */
-               while ((ch = *cp++) != 0) {
-                       bad_type = bad_ref_char(ch);
-                       if (bad_type)
-                               return CHECK_REF_FORMAT_ERROR;
-                       if (ch == '/')
-                               break;
-                       if (last == '.' && ch == '.')
-                               return CHECK_REF_FORMAT_ERROR;
-                       if (last == '@' && ch == '{')
-                               return CHECK_REF_FORMAT_ERROR;
-                       last = ch;
-               }
-               level++;
-               if (!ch) {
-                       if (ref <= cp - 2 && cp[-2] == '.')
-                               return CHECK_REF_FORMAT_ERROR;
-                       if (level < 2)
-                               return CHECK_REF_FORMAT_ONELEVEL;
-                       if (has_extension(ref, ".lock"))
-                               return CHECK_REF_FORMAT_ERROR;
-                       return ret;
+       }
+       if (cp == ref)
+               return -1; /* Component has zero length. */
+       if (ref[0] == '.') {
+               if (!(flags & REFNAME_DOT_COMPONENT))
+                       return -1; /* Component starts with '.'. */
+               /*
+                * Even if leading dots are allowed, don't allow "."
+                * as a component (".." is prevented by a rule above).
+                */
+               if (ref[1] == '\0')
+                       return -1; /* Component equals ".". */
+       }
+       if (cp - ref >= 5 && !memcmp(cp - 5, ".lock", 5))
+               return -1; /* Refname ends with ".lock". */
+       return cp - ref;
+}
+
+int check_refname_format(const char *ref, int flags)
+{
+       int component_len, component_count = 0;
+
+       while (1) {
+               /* We are at the start of a path component. */
+               component_len = check_refname_component(ref, flags);
+               if (component_len < 0) {
+                       if ((flags & REFNAME_REFSPEC_PATTERN) &&
+                                       ref[0] == '*' &&
+                                       (ref[1] == '\0' || ref[1] == '/')) {
+                               /* Accept one wildcard as a full refname component. */
+                               flags &= ~REFNAME_REFSPEC_PATTERN;
+                               component_len = 1;
+                       } else {
+                               return -1;
+                       }
                }
+               component_count++;
+               if (ref[component_len] == '\0')
+                       break;
+               /* Skip to next component. */
+               ref += component_len + 1;
        }
+
+       if (ref[component_len - 1] == '.')
+               return -1; /* Refname ends with '.'. */
+       if (!(flags & REFNAME_ALLOW_ONELEVEL) && component_count < 2)
+               return -1; /* Refname has only one component. */
+       return 0;
 }
 
 const char *prettify_refname(const char *name)
@@ -888,13 +1003,6 @@ const char *ref_rev_parse_rules[] = {
        NULL
 };
 
-const char *ref_fetch_rules[] = {
-       "%.*s",
-       "refs/%.*s",
-       "refs/heads/%.*s",
-       NULL
-};
-
 int refname_match(const char *abbrev_name, const char *full_name, const char **rules)
 {
        const char **p;
@@ -912,7 +1020,7 @@ int refname_match(const char *abbrev_name, const char *full_name, const char **r
 static struct ref_lock *verify_lock(struct ref_lock *lock,
        const unsigned char *old_sha1, int mustexist)
 {
-       if (!resolve_ref(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
+       if (read_ref_full(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
                error("Can't verify ref %s", lock->ref_name);
                unlock_ref(lock);
                return NULL;
@@ -968,6 +1076,94 @@ static int is_refname_available(const char *ref, const char *oldref,
        return 1;
 }
 
+/*
+ * *string and *len will only be substituted, and *string returned (for
+ * later free()ing) if the string passed in is a magic short-hand form
+ * to name a branch.
+ */
+static char *substitute_branch_name(const char **string, int *len)
+{
+       struct strbuf buf = STRBUF_INIT;
+       int ret = interpret_branch_name(*string, &buf);
+
+       if (ret == *len) {
+               size_t size;
+               *string = strbuf_detach(&buf, &size);
+               *len = size;
+               return (char *)*string;
+       }
+
+       return NULL;
+}
+
+int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
+{
+       char *last_branch = substitute_branch_name(&str, &len);
+       const char **p, *r;
+       int refs_found = 0;
+
+       *ref = NULL;
+       for (p = ref_rev_parse_rules; *p; p++) {
+               char fullref[PATH_MAX];
+               unsigned char sha1_from_ref[20];
+               unsigned char *this_result;
+               int flag;
+
+               this_result = refs_found ? sha1_from_ref : sha1;
+               mksnpath(fullref, sizeof(fullref), *p, len, str);
+               r = resolve_ref(fullref, this_result, 1, &flag);
+               if (r) {
+                       if (!refs_found++)
+                               *ref = xstrdup(r);
+                       if (!warn_ambiguous_refs)
+                               break;
+               } else if ((flag & REF_ISSYMREF) && strcmp(fullref, "HEAD")) {
+                       warning("ignoring dangling symref %s.", fullref);
+               } else if ((flag & REF_ISBROKEN) && strchr(fullref, '/')) {
+                       warning("ignoring broken ref %s.", fullref);
+               }
+       }
+       free(last_branch);
+       return refs_found;
+}
+
+int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
+{
+       char *last_branch = substitute_branch_name(&str, &len);
+       const char **p;
+       int logs_found = 0;
+
+       *log = NULL;
+       for (p = ref_rev_parse_rules; *p; p++) {
+               struct stat st;
+               unsigned char hash[20];
+               char path[PATH_MAX];
+               const char *ref, *it;
+
+               mksnpath(path, sizeof(path), *p, len, str);
+               ref = resolve_ref(path, hash, 1, NULL);
+               if (!ref)
+                       continue;
+               if (!stat(git_path("logs/%s", path), &st) &&
+                   S_ISREG(st.st_mode))
+                       it = path;
+               else if (strcmp(ref, path) &&
+                        !stat(git_path("logs/%s", ref), &st) &&
+                        S_ISREG(st.st_mode))
+                       it = ref;
+               else
+                       continue;
+               if (!logs_found++) {
+                       *log = xstrdup(it);
+                       hashcpy(sha1, hash);
+               }
+               if (!warn_ambiguous_refs)
+                       break;
+       }
+       free(last_branch);
+       return logs_found;
+}
+
 static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char *old_sha1, int flags, int *type_p)
 {
        char *ref_file;
@@ -1049,7 +1245,7 @@ static struct ref_lock *lock_ref_sha1_basic(const char *ref, const unsigned char
 struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 {
        char refpath[PATH_MAX];
-       if (check_ref_format(ref))
+       if (check_refname_format(ref, 0))
                return NULL;
        strcpy(refpath, mkpath("refs/%s", ref));
        return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
@@ -1057,13 +1253,9 @@ struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 
 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 {
-       switch (check_ref_format(ref)) {
-       default:
+       if (check_refname_format(ref, REFNAME_ALLOW_ONELEVEL))
                return NULL;
-       case 0:
-       case CHECK_REF_FORMAT_ONELEVEL:
-               return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
-       }
+       return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
 }
 
 static struct lock_file packlock;
@@ -1135,7 +1327,7 @@ int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
        ret |= repack_without_ref(refname);
 
        unlink_or_warn(git_path("logs/%s", lock->ref_name));
-       invalidate_cached_refs();
+       invalidate_ref_cache(NULL);
        unlock_ref(lock);
        return ret;
 }
@@ -1151,7 +1343,6 @@ int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
 
 int rename_ref(const char *oldref, const char *newref, const char *logmsg)
 {
-       static const char renamed_ref[] = "RENAMED-REF";
        unsigned char sha1[20], orig_sha1[20];
        int flag = 0, logmoved = 0;
        struct ref_lock *lock;
@@ -1175,13 +1366,6 @@ int rename_ref(const char *oldref, const char *newref, const char *logmsg)
        if (!is_refname_available(newref, oldref, get_loose_refs(NULL), 0))
                return 1;
 
-       lock = lock_ref_sha1_basic(renamed_ref, NULL, 0, NULL);
-       if (!lock)
-               return error("unable to lock %s", renamed_ref);
-       lock->force_write = 1;
-       if (write_ref_sha1(lock, orig_sha1, logmsg))
-               return error("unable to save current sha1 in %s", renamed_ref);
-
        if (log && rename(git_path("logs/%s", oldref), git_path(TMP_RENAMED_LOG)))
                return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
                        oldref, strerror(errno));
@@ -1191,7 +1375,8 @@ int rename_ref(const char *oldref, const char *newref, const char *logmsg)
                goto rollback;
        }
 
-       if (resolve_ref(newref, sha1, 1, &flag) && delete_ref(newref, sha1, REF_NODEREF)) {
+       if (!read_ref_full(newref, sha1, 1, &flag) &&
+           delete_ref(newref, sha1, REF_NODEREF)) {
                if (errno==EISDIR) {
                        if (remove_empty_directories(git_path("%s", newref))) {
                                error("Directory not empty: %s", newref);
@@ -1416,7 +1601,7 @@ int write_ref_sha1(struct ref_lock *lock,
        }
        o = parse_object(sha1);
        if (!o) {
-               error("Trying to write ref %s with nonexistant object %s",
+               error("Trying to write ref %s with nonexistent object %s",
                        lock->ref_name, sha1_to_hex(sha1));
                unlock_ref(lock);
                return -1;
@@ -1434,7 +1619,7 @@ int write_ref_sha1(struct ref_lock *lock,
                unlock_ref(lock);
                return -1;
        }
-       invalidate_cached_refs();
+       clear_loose_ref_cache(get_ref_cache(NULL));
        if (log_ref_write(lock->ref_name, lock->old_sha1, sha1, logmsg) < 0 ||
            (strcmp(lock->ref_name, lock->orig_ref_name) &&
             log_ref_write(lock->orig_ref_name, lock->old_sha1, sha1, logmsg) < 0)) {
@@ -1743,7 +1928,7 @@ static int do_for_each_reflog(const char *base, each_ref_fn fn, void *cb_data)
                                retval = do_for_each_reflog(log, fn, cb_data);
                        } else {
                                unsigned char sha1[20];
-                               if (!resolve_ref(log, sha1, 0, NULL))
+                               if (read_ref_full(log, sha1, 0, NULL))
                                        retval = error("bad ref for %s", log);
                                else
                                        retval = fn(log, sha1, 0, cb_data);
@@ -1791,6 +1976,12 @@ int update_ref(const char *action, const char *refname,
        return 0;
 }
 
+int ref_exists(const char *refname)
+{
+       unsigned char sha1[20];
+       return !!resolve_ref(refname, sha1, 1, NULL);
+}
+
 struct ref *find_ref_by_name(const struct ref *list, const char *name)
 {
        for ( ; list; list = list->next)
@@ -1880,7 +2071,6 @@ char *shorten_unambiguous_ref(const char *ref, int strict)
                 */
                for (j = 0; j < rules_to_fail; j++) {
                        const char *rule = ref_rev_parse_rules[j];
-                       unsigned char short_objectname[20];
                        char refname[PATH_MAX];
 
                        /* skip matched rule */
@@ -1894,7 +2084,7 @@ char *shorten_unambiguous_ref(const char *ref, int strict)
                         */
                        mksnpath(refname, sizeof(refname),
                                 rule, short_name_len, short_name);
-                       if (!read_ref(refname, short_objectname))
+                       if (ref_exists(refname))
                                break;
                }