notes.con commit Sync with maint (117ddef)
   1#include "cache.h"
   2#include "config.h"
   3#include "notes.h"
   4#include "blob.h"
   5#include "tree.h"
   6#include "utf8.h"
   7#include "strbuf.h"
   8#include "tree-walk.h"
   9#include "string-list.h"
  10#include "refs.h"
  11
  12/*
  13 * Use a non-balancing simple 16-tree structure with struct int_node as
  14 * internal nodes, and struct leaf_node as leaf nodes. Each int_node has a
  15 * 16-array of pointers to its children.
  16 * The bottom 2 bits of each pointer is used to identify the pointer type
  17 * - ptr & 3 == 0 - NULL pointer, assert(ptr == NULL)
  18 * - ptr & 3 == 1 - pointer to next internal node - cast to struct int_node *
  19 * - ptr & 3 == 2 - pointer to note entry - cast to struct leaf_node *
  20 * - ptr & 3 == 3 - pointer to subtree entry - cast to struct leaf_node *
  21 *
  22 * The root node is a statically allocated struct int_node.
  23 */
  24struct int_node {
  25        void *a[16];
  26};
  27
  28/*
  29 * Leaf nodes come in two variants, note entries and subtree entries,
  30 * distinguished by the LSb of the leaf node pointer (see above).
  31 * As a note entry, the key is the SHA1 of the referenced object, and the
  32 * value is the SHA1 of the note object.
  33 * As a subtree entry, the key is the prefix SHA1 (w/trailing NULs) of the
  34 * referenced object, using the last byte of the key to store the length of
  35 * the prefix. The value is the SHA1 of the tree object containing the notes
  36 * subtree.
  37 */
  38struct leaf_node {
  39        struct object_id key_oid;
  40        struct object_id val_oid;
  41};
  42
  43/*
  44 * A notes tree may contain entries that are not notes, and that do not follow
  45 * the naming conventions of notes. There are typically none/few of these, but
  46 * we still need to keep track of them. Keep a simple linked list sorted alpha-
  47 * betically on the non-note path. The list is populated when parsing tree
  48 * objects in load_subtree(), and the non-notes are correctly written back into
  49 * the tree objects produced by write_notes_tree().
  50 */
  51struct non_note {
  52        struct non_note *next; /* grounded (last->next == NULL) */
  53        char *path;
  54        unsigned int mode;
  55        struct object_id oid;
  56};
  57
  58#define PTR_TYPE_NULL     0
  59#define PTR_TYPE_INTERNAL 1
  60#define PTR_TYPE_NOTE     2
  61#define PTR_TYPE_SUBTREE  3
  62
  63#define GET_PTR_TYPE(ptr)       ((uintptr_t) (ptr) & 3)
  64#define CLR_PTR_TYPE(ptr)       ((void *) ((uintptr_t) (ptr) & ~3))
  65#define SET_PTR_TYPE(ptr, type) ((void *) ((uintptr_t) (ptr) | (type)))
  66
  67#define GET_NIBBLE(n, sha1) (((sha1[(n) >> 1]) >> ((~(n) & 0x01) << 2)) & 0x0f)
  68
  69#define KEY_INDEX (GIT_SHA1_RAWSZ - 1)
  70#define FANOUT_PATH_SEPARATORS ((GIT_SHA1_HEXSZ / 2) - 1)
  71#define SUBTREE_SHA1_PREFIXCMP(key_sha1, subtree_sha1) \
  72        (memcmp(key_sha1, subtree_sha1, subtree_sha1[KEY_INDEX]))
  73
  74struct notes_tree default_notes_tree;
  75
  76static struct string_list display_notes_refs = STRING_LIST_INIT_NODUP;
  77static struct notes_tree **display_notes_trees;
  78
  79static void load_subtree(struct notes_tree *t, struct leaf_node *subtree,
  80                struct int_node *node, unsigned int n);
  81
  82/*
  83 * Search the tree until the appropriate location for the given key is found:
  84 * 1. Start at the root node, with n = 0
  85 * 2. If a[0] at the current level is a matching subtree entry, unpack that
  86 *    subtree entry and remove it; restart search at the current level.
  87 * 3. Use the nth nibble of the key as an index into a:
  88 *    - If a[n] is an int_node, recurse from #2 into that node and increment n
  89 *    - If a matching subtree entry, unpack that subtree entry (and remove it);
  90 *      restart search at the current level.
  91 *    - Otherwise, we have found one of the following:
  92 *      - a subtree entry which does not match the key
  93 *      - a note entry which may or may not match the key
  94 *      - an unused leaf node (NULL)
  95 *      In any case, set *tree and *n, and return pointer to the tree location.
  96 */
  97static void **note_tree_search(struct notes_tree *t, struct int_node **tree,
  98                unsigned char *n, const unsigned char *key_sha1)
  99{
 100        struct leaf_node *l;
 101        unsigned char i;
 102        void *p = (*tree)->a[0];
 103
 104        if (GET_PTR_TYPE(p) == PTR_TYPE_SUBTREE) {
 105                l = (struct leaf_node *) CLR_PTR_TYPE(p);
 106                if (!SUBTREE_SHA1_PREFIXCMP(key_sha1, l->key_oid.hash)) {
 107                        /* unpack tree and resume search */
 108                        (*tree)->a[0] = NULL;
 109                        load_subtree(t, l, *tree, *n);
 110                        free(l);
 111                        return note_tree_search(t, tree, n, key_sha1);
 112                }
 113        }
 114
 115        i = GET_NIBBLE(*n, key_sha1);
 116        p = (*tree)->a[i];
 117        switch (GET_PTR_TYPE(p)) {
 118        case PTR_TYPE_INTERNAL:
 119                *tree = CLR_PTR_TYPE(p);
 120                (*n)++;
 121                return note_tree_search(t, tree, n, key_sha1);
 122        case PTR_TYPE_SUBTREE:
 123                l = (struct leaf_node *) CLR_PTR_TYPE(p);
 124                if (!SUBTREE_SHA1_PREFIXCMP(key_sha1, l->key_oid.hash)) {
 125                        /* unpack tree and resume search */
 126                        (*tree)->a[i] = NULL;
 127                        load_subtree(t, l, *tree, *n);
 128                        free(l);
 129                        return note_tree_search(t, tree, n, key_sha1);
 130                }
 131                /* fall through */
 132        default:
 133                return &((*tree)->a[i]);
 134        }
 135}
 136
 137/*
 138 * To find a leaf_node:
 139 * Search to the tree location appropriate for the given key:
 140 * If a note entry with matching key, return the note entry, else return NULL.
 141 */
 142static struct leaf_node *note_tree_find(struct notes_tree *t,
 143                struct int_node *tree, unsigned char n,
 144                const unsigned char *key_sha1)
 145{
 146        void **p = note_tree_search(t, &tree, &n, key_sha1);
 147        if (GET_PTR_TYPE(*p) == PTR_TYPE_NOTE) {
 148                struct leaf_node *l = (struct leaf_node *) CLR_PTR_TYPE(*p);
 149                if (!hashcmp(key_sha1, l->key_oid.hash))
 150                        return l;
 151        }
 152        return NULL;
 153}
 154
 155/*
 156 * How to consolidate an int_node:
 157 * If there are > 1 non-NULL entries, give up and return non-zero.
 158 * Otherwise replace the int_node at the given index in the given parent node
 159 * with the only NOTE entry (or a NULL entry if no entries) from the given
 160 * tree, and return 0.
 161 */
 162static int note_tree_consolidate(struct int_node *tree,
 163        struct int_node *parent, unsigned char index)
 164{
 165        unsigned int i;
 166        void *p = NULL;
 167
 168        assert(tree && parent);
 169        assert(CLR_PTR_TYPE(parent->a[index]) == tree);
 170
 171        for (i = 0; i < 16; i++) {
 172                if (GET_PTR_TYPE(tree->a[i]) != PTR_TYPE_NULL) {
 173                        if (p) /* more than one entry */
 174                                return -2;
 175                        p = tree->a[i];
 176                }
 177        }
 178
 179        if (p && (GET_PTR_TYPE(p) != PTR_TYPE_NOTE))
 180                return -2;
 181        /* replace tree with p in parent[index] */
 182        parent->a[index] = p;
 183        free(tree);
 184        return 0;
 185}
 186
 187/*
 188 * To remove a leaf_node:
 189 * Search to the tree location appropriate for the given leaf_node's key:
 190 * - If location does not hold a matching entry, abort and do nothing.
 191 * - Copy the matching entry's value into the given entry.
 192 * - Replace the matching leaf_node with a NULL entry (and free the leaf_node).
 193 * - Consolidate int_nodes repeatedly, while walking up the tree towards root.
 194 */
 195static void note_tree_remove(struct notes_tree *t,
 196                struct int_node *tree, unsigned char n,
 197                struct leaf_node *entry)
 198{
 199        struct leaf_node *l;
 200        struct int_node *parent_stack[GIT_SHA1_RAWSZ];
 201        unsigned char i, j;
 202        void **p = note_tree_search(t, &tree, &n, entry->key_oid.hash);
 203
 204        assert(GET_PTR_TYPE(entry) == 0); /* no type bits set */
 205        if (GET_PTR_TYPE(*p) != PTR_TYPE_NOTE)
 206                return; /* type mismatch, nothing to remove */
 207        l = (struct leaf_node *) CLR_PTR_TYPE(*p);
 208        if (oidcmp(&l->key_oid, &entry->key_oid))
 209                return; /* key mismatch, nothing to remove */
 210
 211        /* we have found a matching entry */
 212        oidcpy(&entry->val_oid, &l->val_oid);
 213        free(l);
 214        *p = SET_PTR_TYPE(NULL, PTR_TYPE_NULL);
 215
 216        /* consolidate this tree level, and parent levels, if possible */
 217        if (!n)
 218                return; /* cannot consolidate top level */
 219        /* first, build stack of ancestors between root and current node */
 220        parent_stack[0] = t->root;
 221        for (i = 0; i < n; i++) {
 222                j = GET_NIBBLE(i, entry->key_oid.hash);
 223                parent_stack[i + 1] = CLR_PTR_TYPE(parent_stack[i]->a[j]);
 224        }
 225        assert(i == n && parent_stack[i] == tree);
 226        /* next, unwind stack until note_tree_consolidate() is done */
 227        while (i > 0 &&
 228               !note_tree_consolidate(parent_stack[i], parent_stack[i - 1],
 229                                      GET_NIBBLE(i - 1, entry->key_oid.hash)))
 230                i--;
 231}
 232
 233/*
 234 * To insert a leaf_node:
 235 * Search to the tree location appropriate for the given leaf_node's key:
 236 * - If location is unused (NULL), store the tweaked pointer directly there
 237 * - If location holds a note entry that matches the note-to-be-inserted, then
 238 *   combine the two notes (by calling the given combine_notes function).
 239 * - If location holds a note entry that matches the subtree-to-be-inserted,
 240 *   then unpack the subtree-to-be-inserted into the location.
 241 * - If location holds a matching subtree entry, unpack the subtree at that
 242 *   location, and restart the insert operation from that level.
 243 * - Else, create a new int_node, holding both the node-at-location and the
 244 *   node-to-be-inserted, and store the new int_node into the location.
 245 */
 246static int note_tree_insert(struct notes_tree *t, struct int_node *tree,
 247                unsigned char n, struct leaf_node *entry, unsigned char type,
 248                combine_notes_fn combine_notes)
 249{
 250        struct int_node *new_node;
 251        struct leaf_node *l;
 252        void **p = note_tree_search(t, &tree, &n, entry->key_oid.hash);
 253        int ret = 0;
 254
 255        assert(GET_PTR_TYPE(entry) == 0); /* no type bits set */
 256        l = (struct leaf_node *) CLR_PTR_TYPE(*p);
 257        switch (GET_PTR_TYPE(*p)) {
 258        case PTR_TYPE_NULL:
 259                assert(!*p);
 260                if (is_null_oid(&entry->val_oid))
 261                        free(entry);
 262                else
 263                        *p = SET_PTR_TYPE(entry, type);
 264                return 0;
 265        case PTR_TYPE_NOTE:
 266                switch (type) {
 267                case PTR_TYPE_NOTE:
 268                        if (!oidcmp(&l->key_oid, &entry->key_oid)) {
 269                                /* skip concatenation if l == entry */
 270                                if (!oidcmp(&l->val_oid, &entry->val_oid))
 271                                        return 0;
 272
 273                                ret = combine_notes(l->val_oid.hash,
 274                                                    entry->val_oid.hash);
 275                                if (!ret && is_null_oid(&l->val_oid))
 276                                        note_tree_remove(t, tree, n, entry);
 277                                free(entry);
 278                                return ret;
 279                        }
 280                        break;
 281                case PTR_TYPE_SUBTREE:
 282                        if (!SUBTREE_SHA1_PREFIXCMP(l->key_oid.hash,
 283                                                    entry->key_oid.hash)) {
 284                                /* unpack 'entry' */
 285                                load_subtree(t, entry, tree, n);
 286                                free(entry);
 287                                return 0;
 288                        }
 289                        break;
 290                }
 291                break;
 292        case PTR_TYPE_SUBTREE:
 293                if (!SUBTREE_SHA1_PREFIXCMP(entry->key_oid.hash, l->key_oid.hash)) {
 294                        /* unpack 'l' and restart insert */
 295                        *p = NULL;
 296                        load_subtree(t, l, tree, n);
 297                        free(l);
 298                        return note_tree_insert(t, tree, n, entry, type,
 299                                                combine_notes);
 300                }
 301                break;
 302        }
 303
 304        /* non-matching leaf_node */
 305        assert(GET_PTR_TYPE(*p) == PTR_TYPE_NOTE ||
 306               GET_PTR_TYPE(*p) == PTR_TYPE_SUBTREE);
 307        if (is_null_oid(&entry->val_oid)) { /* skip insertion of empty note */
 308                free(entry);
 309                return 0;
 310        }
 311        new_node = (struct int_node *) xcalloc(1, sizeof(struct int_node));
 312        ret = note_tree_insert(t, new_node, n + 1, l, GET_PTR_TYPE(*p),
 313                               combine_notes);
 314        if (ret)
 315                return ret;
 316        *p = SET_PTR_TYPE(new_node, PTR_TYPE_INTERNAL);
 317        return note_tree_insert(t, new_node, n + 1, entry, type, combine_notes);
 318}
 319
 320/* Free the entire notes data contained in the given tree */
 321static void note_tree_free(struct int_node *tree)
 322{
 323        unsigned int i;
 324        for (i = 0; i < 16; i++) {
 325                void *p = tree->a[i];
 326                switch (GET_PTR_TYPE(p)) {
 327                case PTR_TYPE_INTERNAL:
 328                        note_tree_free(CLR_PTR_TYPE(p));
 329                        /* fall through */
 330                case PTR_TYPE_NOTE:
 331                case PTR_TYPE_SUBTREE:
 332                        free(CLR_PTR_TYPE(p));
 333                }
 334        }
 335}
 336
 337/*
 338 * Convert a partial SHA1 hex string to the corresponding partial SHA1 value.
 339 * - hex      - Partial SHA1 segment in ASCII hex format
 340 * - hex_len  - Length of above segment. Must be multiple of 2 between 0 and 40
 341 * - sha1     - Partial SHA1 value is written here
 342 * - sha1_len - Max #bytes to store in sha1, Must be >= hex_len / 2, and < 20
 343 * Returns -1 on error (invalid arguments or invalid SHA1 (not in hex format)).
 344 * Otherwise, returns number of bytes written to sha1 (i.e. hex_len / 2).
 345 * Pads sha1 with NULs up to sha1_len (not included in returned length).
 346 */
 347static int get_oid_hex_segment(const char *hex, unsigned int hex_len,
 348                unsigned char *oid, unsigned int oid_len)
 349{
 350        unsigned int i, len = hex_len >> 1;
 351        if (hex_len % 2 != 0 || len > oid_len)
 352                return -1;
 353        for (i = 0; i < len; i++) {
 354                unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
 355                if (val & ~0xff)
 356                        return -1;
 357                *oid++ = val;
 358                hex += 2;
 359        }
 360        for (; i < oid_len; i++)
 361                *oid++ = 0;
 362        return len;
 363}
 364
 365static int non_note_cmp(const struct non_note *a, const struct non_note *b)
 366{
 367        return strcmp(a->path, b->path);
 368}
 369
 370/* note: takes ownership of path string */
 371static void add_non_note(struct notes_tree *t, char *path,
 372                unsigned int mode, const unsigned char *sha1)
 373{
 374        struct non_note *p = t->prev_non_note, *n;
 375        n = (struct non_note *) xmalloc(sizeof(struct non_note));
 376        n->next = NULL;
 377        n->path = path;
 378        n->mode = mode;
 379        hashcpy(n->oid.hash, sha1);
 380        t->prev_non_note = n;
 381
 382        if (!t->first_non_note) {
 383                t->first_non_note = n;
 384                return;
 385        }
 386
 387        if (non_note_cmp(p, n) < 0)
 388                ; /* do nothing  */
 389        else if (non_note_cmp(t->first_non_note, n) <= 0)
 390                p = t->first_non_note;
 391        else {
 392                /* n sorts before t->first_non_note */
 393                n->next = t->first_non_note;
 394                t->first_non_note = n;
 395                return;
 396        }
 397
 398        /* n sorts equal or after p */
 399        while (p->next && non_note_cmp(p->next, n) <= 0)
 400                p = p->next;
 401
 402        if (non_note_cmp(p, n) == 0) { /* n ~= p; overwrite p with n */
 403                assert(strcmp(p->path, n->path) == 0);
 404                p->mode = n->mode;
 405                oidcpy(&p->oid, &n->oid);
 406                free(n);
 407                t->prev_non_note = p;
 408                return;
 409        }
 410
 411        /* n sorts between p and p->next */
 412        n->next = p->next;
 413        p->next = n;
 414}
 415
 416static void load_subtree(struct notes_tree *t, struct leaf_node *subtree,
 417                struct int_node *node, unsigned int n)
 418{
 419        struct object_id object_oid;
 420        unsigned int prefix_len;
 421        void *buf;
 422        struct tree_desc desc;
 423        struct name_entry entry;
 424        int len, path_len;
 425        unsigned char type;
 426        struct leaf_node *l;
 427
 428        buf = fill_tree_descriptor(&desc, subtree->val_oid.hash);
 429        if (!buf)
 430                die("Could not read %s for notes-index",
 431                     oid_to_hex(&subtree->val_oid));
 432
 433        prefix_len = subtree->key_oid.hash[KEY_INDEX];
 434        assert(prefix_len * 2 >= n);
 435        memcpy(object_oid.hash, subtree->key_oid.hash, prefix_len);
 436        while (tree_entry(&desc, &entry)) {
 437                path_len = strlen(entry.path);
 438                len = get_oid_hex_segment(entry.path, path_len,
 439                                object_oid.hash + prefix_len, GIT_SHA1_RAWSZ - prefix_len);
 440                if (len < 0)
 441                        goto handle_non_note; /* entry.path is not a SHA1 */
 442                len += prefix_len;
 443
 444                /*
 445                 * If object SHA1 is complete (len == 20), assume note object
 446                 * If object SHA1 is incomplete (len < 20), and current
 447                 * component consists of 2 hex chars, assume note subtree
 448                 */
 449                if (len <= GIT_SHA1_RAWSZ) {
 450                        type = PTR_TYPE_NOTE;
 451                        l = (struct leaf_node *)
 452                                xcalloc(1, sizeof(struct leaf_node));
 453                        oidcpy(&l->key_oid, &object_oid);
 454                        oidcpy(&l->val_oid, entry.oid);
 455                        if (len < GIT_SHA1_RAWSZ) {
 456                                if (!S_ISDIR(entry.mode) || path_len != 2)
 457                                        goto handle_non_note; /* not subtree */
 458                                l->key_oid.hash[KEY_INDEX] = (unsigned char) len;
 459                                type = PTR_TYPE_SUBTREE;
 460                        }
 461                        if (note_tree_insert(t, node, n, l, type,
 462                                             combine_notes_concatenate))
 463                                die("Failed to load %s %s into notes tree "
 464                                    "from %s",
 465                                    type == PTR_TYPE_NOTE ? "note" : "subtree",
 466                                    oid_to_hex(&l->key_oid), t->ref);
 467                }
 468                continue;
 469
 470handle_non_note:
 471                /*
 472                 * Determine full path for this non-note entry:
 473                 * The filename is already found in entry.path, but the
 474                 * directory part of the path must be deduced from the subtree
 475                 * containing this entry. We assume here that the overall notes
 476                 * tree follows a strict byte-based progressive fanout
 477                 * structure (i.e. using 2/38, 2/2/36, etc. fanouts, and not
 478                 * e.g. 4/36 fanout). This means that if a non-note is found at
 479                 * path "dead/beef", the following code will register it as
 480                 * being found on "de/ad/beef".
 481                 * On the other hand, if you use such non-obvious non-note
 482                 * paths in the middle of a notes tree, you deserve what's
 483                 * coming to you ;). Note that for non-notes that are not
 484                 * SHA1-like at the top level, there will be no problems.
 485                 *
 486                 * To conclude, it is strongly advised to make sure non-notes
 487                 * have at least one non-hex character in the top-level path
 488                 * component.
 489                 */
 490                {
 491                        struct strbuf non_note_path = STRBUF_INIT;
 492                        const char *q = oid_to_hex(&subtree->key_oid);
 493                        int i;
 494                        for (i = 0; i < prefix_len; i++) {
 495                                strbuf_addch(&non_note_path, *q++);
 496                                strbuf_addch(&non_note_path, *q++);
 497                                strbuf_addch(&non_note_path, '/');
 498                        }
 499                        strbuf_addstr(&non_note_path, entry.path);
 500                        add_non_note(t, strbuf_detach(&non_note_path, NULL),
 501                                     entry.mode, entry.oid->hash);
 502                }
 503        }
 504        free(buf);
 505}
 506
 507/*
 508 * Determine optimal on-disk fanout for this part of the notes tree
 509 *
 510 * Given a (sub)tree and the level in the internal tree structure, determine
 511 * whether or not the given existing fanout should be expanded for this
 512 * (sub)tree.
 513 *
 514 * Values of the 'fanout' variable:
 515 * - 0: No fanout (all notes are stored directly in the root notes tree)
 516 * - 1: 2/38 fanout
 517 * - 2: 2/2/36 fanout
 518 * - 3: 2/2/2/34 fanout
 519 * etc.
 520 */
 521static unsigned char determine_fanout(struct int_node *tree, unsigned char n,
 522                unsigned char fanout)
 523{
 524        /*
 525         * The following is a simple heuristic that works well in practice:
 526         * For each even-numbered 16-tree level (remember that each on-disk
 527         * fanout level corresponds to _two_ 16-tree levels), peek at all 16
 528         * entries at that tree level. If all of them are either int_nodes or
 529         * subtree entries, then there are likely plenty of notes below this
 530         * level, so we return an incremented fanout.
 531         */
 532        unsigned int i;
 533        if ((n % 2) || (n > 2 * fanout))
 534                return fanout;
 535        for (i = 0; i < 16; i++) {
 536                switch (GET_PTR_TYPE(tree->a[i])) {
 537                case PTR_TYPE_SUBTREE:
 538                case PTR_TYPE_INTERNAL:
 539                        continue;
 540                default:
 541                        return fanout;
 542                }
 543        }
 544        return fanout + 1;
 545}
 546
 547/* hex SHA1 + 19 * '/' + NUL */
 548#define FANOUT_PATH_MAX GIT_SHA1_HEXSZ + FANOUT_PATH_SEPARATORS + 1
 549
 550static void construct_path_with_fanout(const unsigned char *sha1,
 551                unsigned char fanout, char *path)
 552{
 553        unsigned int i = 0, j = 0;
 554        const char *hex_sha1 = sha1_to_hex(sha1);
 555        assert(fanout < GIT_SHA1_RAWSZ);
 556        while (fanout) {
 557                path[i++] = hex_sha1[j++];
 558                path[i++] = hex_sha1[j++];
 559                path[i++] = '/';
 560                fanout--;
 561        }
 562        xsnprintf(path + i, FANOUT_PATH_MAX - i, "%s", hex_sha1 + j);
 563}
 564
 565static int for_each_note_helper(struct notes_tree *t, struct int_node *tree,
 566                unsigned char n, unsigned char fanout, int flags,
 567                each_note_fn fn, void *cb_data)
 568{
 569        unsigned int i;
 570        void *p;
 571        int ret = 0;
 572        struct leaf_node *l;
 573        static char path[FANOUT_PATH_MAX];
 574
 575        fanout = determine_fanout(tree, n, fanout);
 576        for (i = 0; i < 16; i++) {
 577redo:
 578                p = tree->a[i];
 579                switch (GET_PTR_TYPE(p)) {
 580                case PTR_TYPE_INTERNAL:
 581                        /* recurse into int_node */
 582                        ret = for_each_note_helper(t, CLR_PTR_TYPE(p), n + 1,
 583                                fanout, flags, fn, cb_data);
 584                        break;
 585                case PTR_TYPE_SUBTREE:
 586                        l = (struct leaf_node *) CLR_PTR_TYPE(p);
 587                        /*
 588                         * Subtree entries in the note tree represent parts of
 589                         * the note tree that have not yet been explored. There
 590                         * is a direct relationship between subtree entries at
 591                         * level 'n' in the tree, and the 'fanout' variable:
 592                         * Subtree entries at level 'n <= 2 * fanout' should be
 593                         * preserved, since they correspond exactly to a fanout
 594                         * directory in the on-disk structure. However, subtree
 595                         * entries at level 'n > 2 * fanout' should NOT be
 596                         * preserved, but rather consolidated into the above
 597                         * notes tree level. We achieve this by unconditionally
 598                         * unpacking subtree entries that exist below the
 599                         * threshold level at 'n = 2 * fanout'.
 600                         */
 601                        if (n <= 2 * fanout &&
 602                            flags & FOR_EACH_NOTE_YIELD_SUBTREES) {
 603                                /* invoke callback with subtree */
 604                                unsigned int path_len =
 605                                        l->key_oid.hash[KEY_INDEX] * 2 + fanout;
 606                                assert(path_len < FANOUT_PATH_MAX - 1);
 607                                construct_path_with_fanout(l->key_oid.hash,
 608                                                           fanout,
 609                                                           path);
 610                                /* Create trailing slash, if needed */
 611                                if (path[path_len - 1] != '/')
 612                                        path[path_len++] = '/';
 613                                path[path_len] = '\0';
 614                                ret = fn(&l->key_oid, &l->val_oid,
 615                                         path,
 616                                         cb_data);
 617                        }
 618                        if (n > fanout * 2 ||
 619                            !(flags & FOR_EACH_NOTE_DONT_UNPACK_SUBTREES)) {
 620                                /* unpack subtree and resume traversal */
 621                                tree->a[i] = NULL;
 622                                load_subtree(t, l, tree, n);
 623                                free(l);
 624                                goto redo;
 625                        }
 626                        break;
 627                case PTR_TYPE_NOTE:
 628                        l = (struct leaf_node *) CLR_PTR_TYPE(p);
 629                        construct_path_with_fanout(l->key_oid.hash, fanout,
 630                                                   path);
 631                        ret = fn(&l->key_oid, &l->val_oid, path,
 632                                 cb_data);
 633                        break;
 634                }
 635                if (ret)
 636                        return ret;
 637        }
 638        return 0;
 639}
 640
 641struct tree_write_stack {
 642        struct tree_write_stack *next;
 643        struct strbuf buf;
 644        char path[2]; /* path to subtree in next, if any */
 645};
 646
 647static inline int matches_tree_write_stack(struct tree_write_stack *tws,
 648                const char *full_path)
 649{
 650        return  full_path[0] == tws->path[0] &&
 651                full_path[1] == tws->path[1] &&
 652                full_path[2] == '/';
 653}
 654
 655static void write_tree_entry(struct strbuf *buf, unsigned int mode,
 656                const char *path, unsigned int path_len, const
 657                unsigned char *sha1)
 658{
 659        strbuf_addf(buf, "%o %.*s%c", mode, path_len, path, '\0');
 660        strbuf_add(buf, sha1, GIT_SHA1_RAWSZ);
 661}
 662
 663static void tree_write_stack_init_subtree(struct tree_write_stack *tws,
 664                const char *path)
 665{
 666        struct tree_write_stack *n;
 667        assert(!tws->next);
 668        assert(tws->path[0] == '\0' && tws->path[1] == '\0');
 669        n = (struct tree_write_stack *)
 670                xmalloc(sizeof(struct tree_write_stack));
 671        n->next = NULL;
 672        strbuf_init(&n->buf, 256 * (32 + GIT_SHA1_HEXSZ)); /* assume 256 entries per tree */
 673        n->path[0] = n->path[1] = '\0';
 674        tws->next = n;
 675        tws->path[0] = path[0];
 676        tws->path[1] = path[1];
 677}
 678
 679static int tree_write_stack_finish_subtree(struct tree_write_stack *tws)
 680{
 681        int ret;
 682        struct tree_write_stack *n = tws->next;
 683        struct object_id s;
 684        if (n) {
 685                ret = tree_write_stack_finish_subtree(n);
 686                if (ret)
 687                        return ret;
 688                ret = write_sha1_file(n->buf.buf, n->buf.len, tree_type, s.hash);
 689                if (ret)
 690                        return ret;
 691                strbuf_release(&n->buf);
 692                free(n);
 693                tws->next = NULL;
 694                write_tree_entry(&tws->buf, 040000, tws->path, 2, s.hash);
 695                tws->path[0] = tws->path[1] = '\0';
 696        }
 697        return 0;
 698}
 699
 700static int write_each_note_helper(struct tree_write_stack *tws,
 701                const char *path, unsigned int mode,
 702                const struct object_id *oid)
 703{
 704        size_t path_len = strlen(path);
 705        unsigned int n = 0;
 706        int ret;
 707
 708        /* Determine common part of tree write stack */
 709        while (tws && 3 * n < path_len &&
 710               matches_tree_write_stack(tws, path + 3 * n)) {
 711                n++;
 712                tws = tws->next;
 713        }
 714
 715        /* tws point to last matching tree_write_stack entry */
 716        ret = tree_write_stack_finish_subtree(tws);
 717        if (ret)
 718                return ret;
 719
 720        /* Start subtrees needed to satisfy path */
 721        while (3 * n + 2 < path_len && path[3 * n + 2] == '/') {
 722                tree_write_stack_init_subtree(tws, path + 3 * n);
 723                n++;
 724                tws = tws->next;
 725        }
 726
 727        /* There should be no more directory components in the given path */
 728        assert(memchr(path + 3 * n, '/', path_len - (3 * n)) == NULL);
 729
 730        /* Finally add given entry to the current tree object */
 731        write_tree_entry(&tws->buf, mode, path + 3 * n, path_len - (3 * n),
 732                         oid->hash);
 733
 734        return 0;
 735}
 736
 737struct write_each_note_data {
 738        struct tree_write_stack *root;
 739        struct non_note *next_non_note;
 740};
 741
 742static int write_each_non_note_until(const char *note_path,
 743                struct write_each_note_data *d)
 744{
 745        struct non_note *n = d->next_non_note;
 746        int cmp = 0, ret;
 747        while (n && (!note_path || (cmp = strcmp(n->path, note_path)) <= 0)) {
 748                if (note_path && cmp == 0)
 749                        ; /* do nothing, prefer note to non-note */
 750                else {
 751                        ret = write_each_note_helper(d->root, n->path, n->mode,
 752                                                     &n->oid);
 753                        if (ret)
 754                                return ret;
 755                }
 756                n = n->next;
 757        }
 758        d->next_non_note = n;
 759        return 0;
 760}
 761
 762static int write_each_note(const struct object_id *object_oid,
 763                const struct object_id *note_oid, char *note_path,
 764                void *cb_data)
 765{
 766        struct write_each_note_data *d =
 767                (struct write_each_note_data *) cb_data;
 768        size_t note_path_len = strlen(note_path);
 769        unsigned int mode = 0100644;
 770
 771        if (note_path[note_path_len - 1] == '/') {
 772                /* subtree entry */
 773                note_path_len--;
 774                note_path[note_path_len] = '\0';
 775                mode = 040000;
 776        }
 777        assert(note_path_len <= GIT_SHA1_HEXSZ + FANOUT_PATH_SEPARATORS);
 778
 779        /* Weave non-note entries into note entries */
 780        return  write_each_non_note_until(note_path, d) ||
 781                write_each_note_helper(d->root, note_path, mode, note_oid);
 782}
 783
 784struct note_delete_list {
 785        struct note_delete_list *next;
 786        const unsigned char *sha1;
 787};
 788
 789static int prune_notes_helper(const struct object_id *object_oid,
 790                const struct object_id *note_oid, char *note_path,
 791                void *cb_data)
 792{
 793        struct note_delete_list **l = (struct note_delete_list **) cb_data;
 794        struct note_delete_list *n;
 795
 796        if (has_object_file(object_oid))
 797                return 0; /* nothing to do for this note */
 798
 799        /* failed to find object => prune this note */
 800        n = (struct note_delete_list *) xmalloc(sizeof(*n));
 801        n->next = *l;
 802        n->sha1 = object_oid->hash;
 803        *l = n;
 804        return 0;
 805}
 806
 807int combine_notes_concatenate(unsigned char *cur_sha1,
 808                const unsigned char *new_sha1)
 809{
 810        char *cur_msg = NULL, *new_msg = NULL, *buf;
 811        unsigned long cur_len, new_len, buf_len;
 812        enum object_type cur_type, new_type;
 813        int ret;
 814
 815        /* read in both note blob objects */
 816        if (!is_null_sha1(new_sha1))
 817                new_msg = read_sha1_file(new_sha1, &new_type, &new_len);
 818        if (!new_msg || !new_len || new_type != OBJ_BLOB) {
 819                free(new_msg);
 820                return 0;
 821        }
 822        if (!is_null_sha1(cur_sha1))
 823                cur_msg = read_sha1_file(cur_sha1, &cur_type, &cur_len);
 824        if (!cur_msg || !cur_len || cur_type != OBJ_BLOB) {
 825                free(cur_msg);
 826                free(new_msg);
 827                hashcpy(cur_sha1, new_sha1);
 828                return 0;
 829        }
 830
 831        /* we will separate the notes by two newlines anyway */
 832        if (cur_msg[cur_len - 1] == '\n')
 833                cur_len--;
 834
 835        /* concatenate cur_msg and new_msg into buf */
 836        buf_len = cur_len + 2 + new_len;
 837        buf = (char *) xmalloc(buf_len);
 838        memcpy(buf, cur_msg, cur_len);
 839        buf[cur_len] = '\n';
 840        buf[cur_len + 1] = '\n';
 841        memcpy(buf + cur_len + 2, new_msg, new_len);
 842        free(cur_msg);
 843        free(new_msg);
 844
 845        /* create a new blob object from buf */
 846        ret = write_sha1_file(buf, buf_len, blob_type, cur_sha1);
 847        free(buf);
 848        return ret;
 849}
 850
 851int combine_notes_overwrite(unsigned char *cur_sha1,
 852                const unsigned char *new_sha1)
 853{
 854        hashcpy(cur_sha1, new_sha1);
 855        return 0;
 856}
 857
 858int combine_notes_ignore(unsigned char *cur_sha1,
 859                const unsigned char *new_sha1)
 860{
 861        return 0;
 862}
 863
 864/*
 865 * Add the lines from the named object to list, with trailing
 866 * newlines removed.
 867 */
 868static int string_list_add_note_lines(struct string_list *list,
 869                                      const unsigned char *sha1)
 870{
 871        char *data;
 872        unsigned long len;
 873        enum object_type t;
 874
 875        if (is_null_sha1(sha1))
 876                return 0;
 877
 878        /* read_sha1_file NUL-terminates */
 879        data = read_sha1_file(sha1, &t, &len);
 880        if (t != OBJ_BLOB || !data || !len) {
 881                free(data);
 882                return t != OBJ_BLOB || !data;
 883        }
 884
 885        /*
 886         * If the last line of the file is EOL-terminated, this will
 887         * add an empty string to the list.  But it will be removed
 888         * later, along with any empty strings that came from empty
 889         * lines within the file.
 890         */
 891        string_list_split(list, data, '\n', -1);
 892        free(data);
 893        return 0;
 894}
 895
 896static int string_list_join_lines_helper(struct string_list_item *item,
 897                                         void *cb_data)
 898{
 899        struct strbuf *buf = cb_data;
 900        strbuf_addstr(buf, item->string);
 901        strbuf_addch(buf, '\n');
 902        return 0;
 903}
 904
 905int combine_notes_cat_sort_uniq(unsigned char *cur_sha1,
 906                const unsigned char *new_sha1)
 907{
 908        struct string_list sort_uniq_list = STRING_LIST_INIT_DUP;
 909        struct strbuf buf = STRBUF_INIT;
 910        int ret = 1;
 911
 912        /* read both note blob objects into unique_lines */
 913        if (string_list_add_note_lines(&sort_uniq_list, cur_sha1))
 914                goto out;
 915        if (string_list_add_note_lines(&sort_uniq_list, new_sha1))
 916                goto out;
 917        string_list_remove_empty_items(&sort_uniq_list, 0);
 918        string_list_sort(&sort_uniq_list);
 919        string_list_remove_duplicates(&sort_uniq_list, 0);
 920
 921        /* create a new blob object from sort_uniq_list */
 922        if (for_each_string_list(&sort_uniq_list,
 923                                 string_list_join_lines_helper, &buf))
 924                goto out;
 925
 926        ret = write_sha1_file(buf.buf, buf.len, blob_type, cur_sha1);
 927
 928out:
 929        strbuf_release(&buf);
 930        string_list_clear(&sort_uniq_list, 0);
 931        return ret;
 932}
 933
 934static int string_list_add_one_ref(const char *refname, const struct object_id *oid,
 935                                   int flag, void *cb)
 936{
 937        struct string_list *refs = cb;
 938        if (!unsorted_string_list_has_string(refs, refname))
 939                string_list_append(refs, refname);
 940        return 0;
 941}
 942
 943/*
 944 * The list argument must have strdup_strings set on it.
 945 */
 946void string_list_add_refs_by_glob(struct string_list *list, const char *glob)
 947{
 948        assert(list->strdup_strings);
 949        if (has_glob_specials(glob)) {
 950                for_each_glob_ref(string_list_add_one_ref, glob, list);
 951        } else {
 952                struct object_id oid;
 953                if (get_oid(glob, &oid))
 954                        warning("notes ref %s is invalid", glob);
 955                if (!unsorted_string_list_has_string(list, glob))
 956                        string_list_append(list, glob);
 957        }
 958}
 959
 960void string_list_add_refs_from_colon_sep(struct string_list *list,
 961                                         const char *globs)
 962{
 963        struct string_list split = STRING_LIST_INIT_NODUP;
 964        char *globs_copy = xstrdup(globs);
 965        int i;
 966
 967        string_list_split_in_place(&split, globs_copy, ':', -1);
 968        string_list_remove_empty_items(&split, 0);
 969
 970        for (i = 0; i < split.nr; i++)
 971                string_list_add_refs_by_glob(list, split.items[i].string);
 972
 973        string_list_clear(&split, 0);
 974        free(globs_copy);
 975}
 976
 977static int notes_display_config(const char *k, const char *v, void *cb)
 978{
 979        int *load_refs = cb;
 980
 981        if (*load_refs && !strcmp(k, "notes.displayref")) {
 982                if (!v)
 983                        config_error_nonbool(k);
 984                string_list_add_refs_by_glob(&display_notes_refs, v);
 985        }
 986
 987        return 0;
 988}
 989
 990const char *default_notes_ref(void)
 991{
 992        const char *notes_ref = NULL;
 993        if (!notes_ref)
 994                notes_ref = getenv(GIT_NOTES_REF_ENVIRONMENT);
 995        if (!notes_ref)
 996                notes_ref = notes_ref_name; /* value of core.notesRef config */
 997        if (!notes_ref)
 998                notes_ref = GIT_NOTES_DEFAULT_REF;
 999        return notes_ref;
1000}
1001
1002void init_notes(struct notes_tree *t, const char *notes_ref,
1003                combine_notes_fn combine_notes, int flags)
1004{
1005        struct object_id oid, object_oid;
1006        unsigned mode;
1007        struct leaf_node root_tree;
1008
1009        if (!t)
1010                t = &default_notes_tree;
1011        assert(!t->initialized);
1012
1013        if (!notes_ref)
1014                notes_ref = default_notes_ref();
1015
1016        if (!combine_notes)
1017                combine_notes = combine_notes_concatenate;
1018
1019        t->root = (struct int_node *) xcalloc(1, sizeof(struct int_node));
1020        t->first_non_note = NULL;
1021        t->prev_non_note = NULL;
1022        t->ref = xstrdup_or_null(notes_ref);
1023        t->update_ref = (flags & NOTES_INIT_WRITABLE) ? t->ref : NULL;
1024        t->combine_notes = combine_notes;
1025        t->initialized = 1;
1026        t->dirty = 0;
1027
1028        if (flags & NOTES_INIT_EMPTY || !notes_ref ||
1029            get_sha1_treeish(notes_ref, object_oid.hash))
1030                return;
1031        if (flags & NOTES_INIT_WRITABLE && read_ref(notes_ref, object_oid.hash))
1032                die("Cannot use notes ref %s", notes_ref);
1033        if (get_tree_entry(object_oid.hash, "", oid.hash, &mode))
1034                die("Failed to read notes tree referenced by %s (%s)",
1035                    notes_ref, oid_to_hex(&object_oid));
1036
1037        oidclr(&root_tree.key_oid);
1038        oidcpy(&root_tree.val_oid, &oid);
1039        load_subtree(t, &root_tree, t->root, 0);
1040}
1041
1042struct notes_tree **load_notes_trees(struct string_list *refs, int flags)
1043{
1044        struct string_list_item *item;
1045        int counter = 0;
1046        struct notes_tree **trees;
1047        ALLOC_ARRAY(trees, refs->nr + 1);
1048        for_each_string_list_item(item, refs) {
1049                struct notes_tree *t = xcalloc(1, sizeof(struct notes_tree));
1050                init_notes(t, item->string, combine_notes_ignore, flags);
1051                trees[counter++] = t;
1052        }
1053        trees[counter] = NULL;
1054        return trees;
1055}
1056
1057void init_display_notes(struct display_notes_opt *opt)
1058{
1059        char *display_ref_env;
1060        int load_config_refs = 0;
1061        display_notes_refs.strdup_strings = 1;
1062
1063        assert(!display_notes_trees);
1064
1065        if (!opt || opt->use_default_notes > 0 ||
1066            (opt->use_default_notes == -1 && !opt->extra_notes_refs.nr)) {
1067                string_list_append(&display_notes_refs, default_notes_ref());
1068                display_ref_env = getenv(GIT_NOTES_DISPLAY_REF_ENVIRONMENT);
1069                if (display_ref_env) {
1070                        string_list_add_refs_from_colon_sep(&display_notes_refs,
1071                                                            display_ref_env);
1072                        load_config_refs = 0;
1073                } else
1074                        load_config_refs = 1;
1075        }
1076
1077        git_config(notes_display_config, &load_config_refs);
1078
1079        if (opt) {
1080                struct string_list_item *item;
1081                for_each_string_list_item(item, &opt->extra_notes_refs)
1082                        string_list_add_refs_by_glob(&display_notes_refs,
1083                                                     item->string);
1084        }
1085
1086        display_notes_trees = load_notes_trees(&display_notes_refs, 0);
1087        string_list_clear(&display_notes_refs, 0);
1088}
1089
1090int add_note(struct notes_tree *t, const struct object_id *object_oid,
1091                const struct object_id *note_oid, combine_notes_fn combine_notes)
1092{
1093        struct leaf_node *l;
1094
1095        if (!t)
1096                t = &default_notes_tree;
1097        assert(t->initialized);
1098        t->dirty = 1;
1099        if (!combine_notes)
1100                combine_notes = t->combine_notes;
1101        l = (struct leaf_node *) xmalloc(sizeof(struct leaf_node));
1102        oidcpy(&l->key_oid, object_oid);
1103        oidcpy(&l->val_oid, note_oid);
1104        return note_tree_insert(t, t->root, 0, l, PTR_TYPE_NOTE, combine_notes);
1105}
1106
1107int remove_note(struct notes_tree *t, const unsigned char *object_sha1)
1108{
1109        struct leaf_node l;
1110
1111        if (!t)
1112                t = &default_notes_tree;
1113        assert(t->initialized);
1114        hashcpy(l.key_oid.hash, object_sha1);
1115        oidclr(&l.val_oid);
1116        note_tree_remove(t, t->root, 0, &l);
1117        if (is_null_oid(&l.val_oid)) /* no note was removed */
1118                return 1;
1119        t->dirty = 1;
1120        return 0;
1121}
1122
1123const struct object_id *get_note(struct notes_tree *t,
1124                const struct object_id *oid)
1125{
1126        struct leaf_node *found;
1127
1128        if (!t)
1129                t = &default_notes_tree;
1130        assert(t->initialized);
1131        found = note_tree_find(t, t->root, 0, oid->hash);
1132        return found ? &found->val_oid : NULL;
1133}
1134
1135int for_each_note(struct notes_tree *t, int flags, each_note_fn fn,
1136                void *cb_data)
1137{
1138        if (!t)
1139                t = &default_notes_tree;
1140        assert(t->initialized);
1141        return for_each_note_helper(t, t->root, 0, 0, flags, fn, cb_data);
1142}
1143
1144int write_notes_tree(struct notes_tree *t, unsigned char *result)
1145{
1146        struct tree_write_stack root;
1147        struct write_each_note_data cb_data;
1148        int ret;
1149
1150        if (!t)
1151                t = &default_notes_tree;
1152        assert(t->initialized);
1153
1154        /* Prepare for traversal of current notes tree */
1155        root.next = NULL; /* last forward entry in list is grounded */
1156        strbuf_init(&root.buf, 256 * (32 + GIT_SHA1_HEXSZ)); /* assume 256 entries */
1157        root.path[0] = root.path[1] = '\0';
1158        cb_data.root = &root;
1159        cb_data.next_non_note = t->first_non_note;
1160
1161        /* Write tree objects representing current notes tree */
1162        ret = for_each_note(t, FOR_EACH_NOTE_DONT_UNPACK_SUBTREES |
1163                                FOR_EACH_NOTE_YIELD_SUBTREES,
1164                        write_each_note, &cb_data) ||
1165                write_each_non_note_until(NULL, &cb_data) ||
1166                tree_write_stack_finish_subtree(&root) ||
1167                write_sha1_file(root.buf.buf, root.buf.len, tree_type, result);
1168        strbuf_release(&root.buf);
1169        return ret;
1170}
1171
1172void prune_notes(struct notes_tree *t, int flags)
1173{
1174        struct note_delete_list *l = NULL;
1175
1176        if (!t)
1177                t = &default_notes_tree;
1178        assert(t->initialized);
1179
1180        for_each_note(t, 0, prune_notes_helper, &l);
1181
1182        while (l) {
1183                if (flags & NOTES_PRUNE_VERBOSE)
1184                        printf("%s\n", sha1_to_hex(l->sha1));
1185                if (!(flags & NOTES_PRUNE_DRYRUN))
1186                        remove_note(t, l->sha1);
1187                l = l->next;
1188        }
1189}
1190
1191void free_notes(struct notes_tree *t)
1192{
1193        if (!t)
1194                t = &default_notes_tree;
1195        if (t->root)
1196                note_tree_free(t->root);
1197        free(t->root);
1198        while (t->first_non_note) {
1199                t->prev_non_note = t->first_non_note->next;
1200                free(t->first_non_note->path);
1201                free(t->first_non_note);
1202                t->first_non_note = t->prev_non_note;
1203        }
1204        free(t->ref);
1205        memset(t, 0, sizeof(struct notes_tree));
1206}
1207
1208/*
1209 * Fill the given strbuf with the notes associated with the given object.
1210 *
1211 * If the given notes_tree structure is not initialized, it will be auto-
1212 * initialized to the default value (see documentation for init_notes() above).
1213 * If the given notes_tree is NULL, the internal/default notes_tree will be
1214 * used instead.
1215 *
1216 * (raw != 0) gives the %N userformat; otherwise, the note message is given
1217 * for human consumption.
1218 */
1219static void format_note(struct notes_tree *t, const struct object_id *object_oid,
1220                        struct strbuf *sb, const char *output_encoding, int raw)
1221{
1222        static const char utf8[] = "utf-8";
1223        const struct object_id *oid;
1224        char *msg, *msg_p;
1225        unsigned long linelen, msglen;
1226        enum object_type type;
1227
1228        if (!t)
1229                t = &default_notes_tree;
1230        if (!t->initialized)
1231                init_notes(t, NULL, NULL, 0);
1232
1233        oid = get_note(t, object_oid);
1234        if (!oid)
1235                return;
1236
1237        if (!(msg = read_sha1_file(oid->hash, &type, &msglen)) || type != OBJ_BLOB) {
1238                free(msg);
1239                return;
1240        }
1241
1242        if (output_encoding && *output_encoding &&
1243            !is_encoding_utf8(output_encoding)) {
1244                char *reencoded = reencode_string(msg, output_encoding, utf8);
1245                if (reencoded) {
1246                        free(msg);
1247                        msg = reencoded;
1248                        msglen = strlen(msg);
1249                }
1250        }
1251
1252        /* we will end the annotation by a newline anyway */
1253        if (msglen && msg[msglen - 1] == '\n')
1254                msglen--;
1255
1256        if (!raw) {
1257                const char *ref = t->ref;
1258                if (!ref || !strcmp(ref, GIT_NOTES_DEFAULT_REF)) {
1259                        strbuf_addstr(sb, "\nNotes:\n");
1260                } else {
1261                        if (starts_with(ref, "refs/"))
1262                                ref += 5;
1263                        if (starts_with(ref, "notes/"))
1264                                ref += 6;
1265                        strbuf_addf(sb, "\nNotes (%s):\n", ref);
1266                }
1267        }
1268
1269        for (msg_p = msg; msg_p < msg + msglen; msg_p += linelen + 1) {
1270                linelen = strchrnul(msg_p, '\n') - msg_p;
1271
1272                if (!raw)
1273                        strbuf_addstr(sb, "    ");
1274                strbuf_add(sb, msg_p, linelen);
1275                strbuf_addch(sb, '\n');
1276        }
1277
1278        free(msg);
1279}
1280
1281void format_display_notes(const struct object_id *object_oid,
1282                          struct strbuf *sb, const char *output_encoding, int raw)
1283{
1284        int i;
1285        assert(display_notes_trees);
1286        for (i = 0; display_notes_trees[i]; i++)
1287                format_note(display_notes_trees[i], object_oid, sb,
1288                            output_encoding, raw);
1289}
1290
1291int copy_note(struct notes_tree *t,
1292              const struct object_id *from_obj, const struct object_id *to_obj,
1293              int force, combine_notes_fn combine_notes)
1294{
1295        const struct object_id *note = get_note(t, from_obj);
1296        const struct object_id *existing_note = get_note(t, to_obj);
1297
1298        if (!force && existing_note)
1299                return 1;
1300
1301        if (note)
1302                return add_note(t, to_obj, note, combine_notes);
1303        else if (existing_note)
1304                return add_note(t, to_obj, &null_oid, combine_notes);
1305
1306        return 0;
1307}
1308
1309void expand_notes_ref(struct strbuf *sb)
1310{
1311        if (starts_with(sb->buf, "refs/notes/"))
1312                return; /* we're happy */
1313        else if (starts_with(sb->buf, "notes/"))
1314                strbuf_insert(sb, 0, "refs/", 5);
1315        else
1316                strbuf_insert(sb, 0, "refs/notes/", 11);
1317}
1318
1319void expand_loose_notes_ref(struct strbuf *sb)
1320{
1321        struct object_id object;
1322
1323        if (get_oid(sb->buf, &object)) {
1324                /* fallback to expand_notes_ref */
1325                expand_notes_ref(sb);
1326        }
1327}