notes.con commit Merge branch 'ah/doc-gitattributes-empty-index' (2bc81f2)
   1#include "cache.h"
   2#include "notes.h"
   3#include "blob.h"
   4#include "tree.h"
   5#include "utf8.h"
   6#include "strbuf.h"
   7#include "tree-walk.h"
   8#include "string-list.h"
   9#include "refs.h"
  10
  11/*
  12 * Use a non-balancing simple 16-tree structure with struct int_node as
  13 * internal nodes, and struct leaf_node as leaf nodes. Each int_node has a
  14 * 16-array of pointers to its children.
  15 * The bottom 2 bits of each pointer is used to identify the pointer type
  16 * - ptr & 3 == 0 - NULL pointer, assert(ptr == NULL)
  17 * - ptr & 3 == 1 - pointer to next internal node - cast to struct int_node *
  18 * - ptr & 3 == 2 - pointer to note entry - cast to struct leaf_node *
  19 * - ptr & 3 == 3 - pointer to subtree entry - cast to struct leaf_node *
  20 *
  21 * The root node is a statically allocated struct int_node.
  22 */
  23struct int_node {
  24        void *a[16];
  25};
  26
  27/*
  28 * Leaf nodes come in two variants, note entries and subtree entries,
  29 * distinguished by the LSb of the leaf node pointer (see above).
  30 * As a note entry, the key is the SHA1 of the referenced object, and the
  31 * value is the SHA1 of the note object.
  32 * As a subtree entry, the key is the prefix SHA1 (w/trailing NULs) of the
  33 * referenced object, using the last byte of the key to store the length of
  34 * the prefix. The value is the SHA1 of the tree object containing the notes
  35 * subtree.
  36 */
  37struct leaf_node {
  38        struct object_id key_oid;
  39        struct object_id val_oid;
  40};
  41
  42/*
  43 * A notes tree may contain entries that are not notes, and that do not follow
  44 * the naming conventions of notes. There are typically none/few of these, but
  45 * we still need to keep track of them. Keep a simple linked list sorted alpha-
  46 * betically on the non-note path. The list is populated when parsing tree
  47 * objects in load_subtree(), and the non-notes are correctly written back into
  48 * the tree objects produced by write_notes_tree().
  49 */
  50struct non_note {
  51        struct non_note *next; /* grounded (last->next == NULL) */
  52        char *path;
  53        unsigned int mode;
  54        struct object_id oid;
  55};
  56
  57#define PTR_TYPE_NULL     0
  58#define PTR_TYPE_INTERNAL 1
  59#define PTR_TYPE_NOTE     2
  60#define PTR_TYPE_SUBTREE  3
  61
  62#define GET_PTR_TYPE(ptr)       ((uintptr_t) (ptr) & 3)
  63#define CLR_PTR_TYPE(ptr)       ((void *) ((uintptr_t) (ptr) & ~3))
  64#define SET_PTR_TYPE(ptr, type) ((void *) ((uintptr_t) (ptr) | (type)))
  65
  66#define GET_NIBBLE(n, sha1) (((sha1[(n) >> 1]) >> ((~(n) & 0x01) << 2)) & 0x0f)
  67
  68#define KEY_INDEX (GIT_SHA1_RAWSZ - 1)
  69#define FANOUT_PATH_SEPARATORS ((GIT_SHA1_HEXSZ / 2) - 1)
  70#define SUBTREE_SHA1_PREFIXCMP(key_sha1, subtree_sha1) \
  71        (memcmp(key_sha1, subtree_sha1, subtree_sha1[KEY_INDEX]))
  72
  73struct notes_tree default_notes_tree;
  74
  75static struct string_list display_notes_refs = STRING_LIST_INIT_NODUP;
  76static struct notes_tree **display_notes_trees;
  77
  78static void load_subtree(struct notes_tree *t, struct leaf_node *subtree,
  79                struct int_node *node, unsigned int n);
  80
  81/*
  82 * Search the tree until the appropriate location for the given key is found:
  83 * 1. Start at the root node, with n = 0
  84 * 2. If a[0] at the current level is a matching subtree entry, unpack that
  85 *    subtree entry and remove it; restart search at the current level.
  86 * 3. Use the nth nibble of the key as an index into a:
  87 *    - If a[n] is an int_node, recurse from #2 into that node and increment n
  88 *    - If a matching subtree entry, unpack that subtree entry (and remove it);
  89 *      restart search at the current level.
  90 *    - Otherwise, we have found one of the following:
  91 *      - a subtree entry which does not match the key
  92 *      - a note entry which may or may not match the key
  93 *      - an unused leaf node (NULL)
  94 *      In any case, set *tree and *n, and return pointer to the tree location.
  95 */
  96static void **note_tree_search(struct notes_tree *t, struct int_node **tree,
  97                unsigned char *n, const unsigned char *key_sha1)
  98{
  99        struct leaf_node *l;
 100        unsigned char i;
 101        void *p = (*tree)->a[0];
 102
 103        if (GET_PTR_TYPE(p) == PTR_TYPE_SUBTREE) {
 104                l = (struct leaf_node *) CLR_PTR_TYPE(p);
 105                if (!SUBTREE_SHA1_PREFIXCMP(key_sha1, l->key_oid.hash)) {
 106                        /* unpack tree and resume search */
 107                        (*tree)->a[0] = NULL;
 108                        load_subtree(t, l, *tree, *n);
 109                        free(l);
 110                        return note_tree_search(t, tree, n, key_sha1);
 111                }
 112        }
 113
 114        i = GET_NIBBLE(*n, key_sha1);
 115        p = (*tree)->a[i];
 116        switch (GET_PTR_TYPE(p)) {
 117        case PTR_TYPE_INTERNAL:
 118                *tree = CLR_PTR_TYPE(p);
 119                (*n)++;
 120                return note_tree_search(t, tree, n, key_sha1);
 121        case PTR_TYPE_SUBTREE:
 122                l = (struct leaf_node *) CLR_PTR_TYPE(p);
 123                if (!SUBTREE_SHA1_PREFIXCMP(key_sha1, l->key_oid.hash)) {
 124                        /* unpack tree and resume search */
 125                        (*tree)->a[i] = NULL;
 126                        load_subtree(t, l, *tree, *n);
 127                        free(l);
 128                        return note_tree_search(t, tree, n, key_sha1);
 129                }
 130                /* fall through */
 131        default:
 132                return &((*tree)->a[i]);
 133        }
 134}
 135
 136/*
 137 * To find a leaf_node:
 138 * Search to the tree location appropriate for the given key:
 139 * If a note entry with matching key, return the note entry, else return NULL.
 140 */
 141static struct leaf_node *note_tree_find(struct notes_tree *t,
 142                struct int_node *tree, unsigned char n,
 143                const unsigned char *key_sha1)
 144{
 145        void **p = note_tree_search(t, &tree, &n, key_sha1);
 146        if (GET_PTR_TYPE(*p) == PTR_TYPE_NOTE) {
 147                struct leaf_node *l = (struct leaf_node *) CLR_PTR_TYPE(*p);
 148                if (!hashcmp(key_sha1, l->key_oid.hash))
 149                        return l;
 150        }
 151        return NULL;
 152}
 153
 154/*
 155 * How to consolidate an int_node:
 156 * If there are > 1 non-NULL entries, give up and return non-zero.
 157 * Otherwise replace the int_node at the given index in the given parent node
 158 * with the only NOTE entry (or a NULL entry if no entries) from the given
 159 * tree, and return 0.
 160 */
 161static int note_tree_consolidate(struct int_node *tree,
 162        struct int_node *parent, unsigned char index)
 163{
 164        unsigned int i;
 165        void *p = NULL;
 166
 167        assert(tree && parent);
 168        assert(CLR_PTR_TYPE(parent->a[index]) == tree);
 169
 170        for (i = 0; i < 16; i++) {
 171                if (GET_PTR_TYPE(tree->a[i]) != PTR_TYPE_NULL) {
 172                        if (p) /* more than one entry */
 173                                return -2;
 174                        p = tree->a[i];
 175                }
 176        }
 177
 178        if (p && (GET_PTR_TYPE(p) != PTR_TYPE_NOTE))
 179                return -2;
 180        /* replace tree with p in parent[index] */
 181        parent->a[index] = p;
 182        free(tree);
 183        return 0;
 184}
 185
 186/*
 187 * To remove a leaf_node:
 188 * Search to the tree location appropriate for the given leaf_node's key:
 189 * - If location does not hold a matching entry, abort and do nothing.
 190 * - Copy the matching entry's value into the given entry.
 191 * - Replace the matching leaf_node with a NULL entry (and free the leaf_node).
 192 * - Consolidate int_nodes repeatedly, while walking up the tree towards root.
 193 */
 194static void note_tree_remove(struct notes_tree *t,
 195                struct int_node *tree, unsigned char n,
 196                struct leaf_node *entry)
 197{
 198        struct leaf_node *l;
 199        struct int_node *parent_stack[GIT_SHA1_RAWSZ];
 200        unsigned char i, j;
 201        void **p = note_tree_search(t, &tree, &n, entry->key_oid.hash);
 202
 203        assert(GET_PTR_TYPE(entry) == 0); /* no type bits set */
 204        if (GET_PTR_TYPE(*p) != PTR_TYPE_NOTE)
 205                return; /* type mismatch, nothing to remove */
 206        l = (struct leaf_node *) CLR_PTR_TYPE(*p);
 207        if (oidcmp(&l->key_oid, &entry->key_oid))
 208                return; /* key mismatch, nothing to remove */
 209
 210        /* we have found a matching entry */
 211        oidcpy(&entry->val_oid, &l->val_oid);
 212        free(l);
 213        *p = SET_PTR_TYPE(NULL, PTR_TYPE_NULL);
 214
 215        /* consolidate this tree level, and parent levels, if possible */
 216        if (!n)
 217                return; /* cannot consolidate top level */
 218        /* first, build stack of ancestors between root and current node */
 219        parent_stack[0] = t->root;
 220        for (i = 0; i < n; i++) {
 221                j = GET_NIBBLE(i, entry->key_oid.hash);
 222                parent_stack[i + 1] = CLR_PTR_TYPE(parent_stack[i]->a[j]);
 223        }
 224        assert(i == n && parent_stack[i] == tree);
 225        /* next, unwind stack until note_tree_consolidate() is done */
 226        while (i > 0 &&
 227               !note_tree_consolidate(parent_stack[i], parent_stack[i - 1],
 228                                      GET_NIBBLE(i - 1, entry->key_oid.hash)))
 229                i--;
 230}
 231
 232/*
 233 * To insert a leaf_node:
 234 * Search to the tree location appropriate for the given leaf_node's key:
 235 * - If location is unused (NULL), store the tweaked pointer directly there
 236 * - If location holds a note entry that matches the note-to-be-inserted, then
 237 *   combine the two notes (by calling the given combine_notes function).
 238 * - If location holds a note entry that matches the subtree-to-be-inserted,
 239 *   then unpack the subtree-to-be-inserted into the location.
 240 * - If location holds a matching subtree entry, unpack the subtree at that
 241 *   location, and restart the insert operation from that level.
 242 * - Else, create a new int_node, holding both the node-at-location and the
 243 *   node-to-be-inserted, and store the new int_node into the location.
 244 */
 245static int note_tree_insert(struct notes_tree *t, struct int_node *tree,
 246                unsigned char n, struct leaf_node *entry, unsigned char type,
 247                combine_notes_fn combine_notes)
 248{
 249        struct int_node *new_node;
 250        struct leaf_node *l;
 251        void **p = note_tree_search(t, &tree, &n, entry->key_oid.hash);
 252        int ret = 0;
 253
 254        assert(GET_PTR_TYPE(entry) == 0); /* no type bits set */
 255        l = (struct leaf_node *) CLR_PTR_TYPE(*p);
 256        switch (GET_PTR_TYPE(*p)) {
 257        case PTR_TYPE_NULL:
 258                assert(!*p);
 259                if (is_null_oid(&entry->val_oid))
 260                        free(entry);
 261                else
 262                        *p = SET_PTR_TYPE(entry, type);
 263                return 0;
 264        case PTR_TYPE_NOTE:
 265                switch (type) {
 266                case PTR_TYPE_NOTE:
 267                        if (!oidcmp(&l->key_oid, &entry->key_oid)) {
 268                                /* skip concatenation if l == entry */
 269                                if (!oidcmp(&l->val_oid, &entry->val_oid))
 270                                        return 0;
 271
 272                                ret = combine_notes(l->val_oid.hash,
 273                                                    entry->val_oid.hash);
 274                                if (!ret && is_null_oid(&l->val_oid))
 275                                        note_tree_remove(t, tree, n, entry);
 276                                free(entry);
 277                                return ret;
 278                        }
 279                        break;
 280                case PTR_TYPE_SUBTREE:
 281                        if (!SUBTREE_SHA1_PREFIXCMP(l->key_oid.hash,
 282                                                    entry->key_oid.hash)) {
 283                                /* unpack 'entry' */
 284                                load_subtree(t, entry, tree, n);
 285                                free(entry);
 286                                return 0;
 287                        }
 288                        break;
 289                }
 290                break;
 291        case PTR_TYPE_SUBTREE:
 292                if (!SUBTREE_SHA1_PREFIXCMP(entry->key_oid.hash, l->key_oid.hash)) {
 293                        /* unpack 'l' and restart insert */
 294                        *p = NULL;
 295                        load_subtree(t, l, tree, n);
 296                        free(l);
 297                        return note_tree_insert(t, tree, n, entry, type,
 298                                                combine_notes);
 299                }
 300                break;
 301        }
 302
 303        /* non-matching leaf_node */
 304        assert(GET_PTR_TYPE(*p) == PTR_TYPE_NOTE ||
 305               GET_PTR_TYPE(*p) == PTR_TYPE_SUBTREE);
 306        if (is_null_oid(&entry->val_oid)) { /* skip insertion of empty note */
 307                free(entry);
 308                return 0;
 309        }
 310        new_node = (struct int_node *) xcalloc(1, sizeof(struct int_node));
 311        ret = note_tree_insert(t, new_node, n + 1, l, GET_PTR_TYPE(*p),
 312                               combine_notes);
 313        if (ret)
 314                return ret;
 315        *p = SET_PTR_TYPE(new_node, PTR_TYPE_INTERNAL);
 316        return note_tree_insert(t, new_node, n + 1, entry, type, combine_notes);
 317}
 318
 319/* Free the entire notes data contained in the given tree */
 320static void note_tree_free(struct int_node *tree)
 321{
 322        unsigned int i;
 323        for (i = 0; i < 16; i++) {
 324                void *p = tree->a[i];
 325                switch (GET_PTR_TYPE(p)) {
 326                case PTR_TYPE_INTERNAL:
 327                        note_tree_free(CLR_PTR_TYPE(p));
 328                        /* fall through */
 329                case PTR_TYPE_NOTE:
 330                case PTR_TYPE_SUBTREE:
 331                        free(CLR_PTR_TYPE(p));
 332                }
 333        }
 334}
 335
 336/*
 337 * Convert a partial SHA1 hex string to the corresponding partial SHA1 value.
 338 * - hex      - Partial SHA1 segment in ASCII hex format
 339 * - hex_len  - Length of above segment. Must be multiple of 2 between 0 and 40
 340 * - sha1     - Partial SHA1 value is written here
 341 * - sha1_len - Max #bytes to store in sha1, Must be >= hex_len / 2, and < 20
 342 * Returns -1 on error (invalid arguments or invalid SHA1 (not in hex format)).
 343 * Otherwise, returns number of bytes written to sha1 (i.e. hex_len / 2).
 344 * Pads sha1 with NULs up to sha1_len (not included in returned length).
 345 */
 346static int get_oid_hex_segment(const char *hex, unsigned int hex_len,
 347                unsigned char *oid, unsigned int oid_len)
 348{
 349        unsigned int i, len = hex_len >> 1;
 350        if (hex_len % 2 != 0 || len > oid_len)
 351                return -1;
 352        for (i = 0; i < len; i++) {
 353                unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
 354                if (val & ~0xff)
 355                        return -1;
 356                *oid++ = val;
 357                hex += 2;
 358        }
 359        for (; i < oid_len; i++)
 360                *oid++ = 0;
 361        return len;
 362}
 363
 364static int non_note_cmp(const struct non_note *a, const struct non_note *b)
 365{
 366        return strcmp(a->path, b->path);
 367}
 368
 369/* note: takes ownership of path string */
 370static void add_non_note(struct notes_tree *t, char *path,
 371                unsigned int mode, const unsigned char *sha1)
 372{
 373        struct non_note *p = t->prev_non_note, *n;
 374        n = (struct non_note *) xmalloc(sizeof(struct non_note));
 375        n->next = NULL;
 376        n->path = path;
 377        n->mode = mode;
 378        hashcpy(n->oid.hash, sha1);
 379        t->prev_non_note = n;
 380
 381        if (!t->first_non_note) {
 382                t->first_non_note = n;
 383                return;
 384        }
 385
 386        if (non_note_cmp(p, n) < 0)
 387                ; /* do nothing  */
 388        else if (non_note_cmp(t->first_non_note, n) <= 0)
 389                p = t->first_non_note;
 390        else {
 391                /* n sorts before t->first_non_note */
 392                n->next = t->first_non_note;
 393                t->first_non_note = n;
 394                return;
 395        }
 396
 397        /* n sorts equal or after p */
 398        while (p->next && non_note_cmp(p->next, n) <= 0)
 399                p = p->next;
 400
 401        if (non_note_cmp(p, n) == 0) { /* n ~= p; overwrite p with n */
 402                assert(strcmp(p->path, n->path) == 0);
 403                p->mode = n->mode;
 404                oidcpy(&p->oid, &n->oid);
 405                free(n);
 406                t->prev_non_note = p;
 407                return;
 408        }
 409
 410        /* n sorts between p and p->next */
 411        n->next = p->next;
 412        p->next = n;
 413}
 414
 415static void load_subtree(struct notes_tree *t, struct leaf_node *subtree,
 416                struct int_node *node, unsigned int n)
 417{
 418        struct object_id object_oid;
 419        unsigned int prefix_len;
 420        void *buf;
 421        struct tree_desc desc;
 422        struct name_entry entry;
 423        int len, path_len;
 424        unsigned char type;
 425        struct leaf_node *l;
 426
 427        buf = fill_tree_descriptor(&desc, subtree->val_oid.hash);
 428        if (!buf)
 429                die("Could not read %s for notes-index",
 430                     oid_to_hex(&subtree->val_oid));
 431
 432        prefix_len = subtree->key_oid.hash[KEY_INDEX];
 433        assert(prefix_len * 2 >= n);
 434        memcpy(object_oid.hash, subtree->key_oid.hash, prefix_len);
 435        while (tree_entry(&desc, &entry)) {
 436                path_len = strlen(entry.path);
 437                len = get_oid_hex_segment(entry.path, path_len,
 438                                object_oid.hash + prefix_len, GIT_SHA1_RAWSZ - prefix_len);
 439                if (len < 0)
 440                        goto handle_non_note; /* entry.path is not a SHA1 */
 441                len += prefix_len;
 442
 443                /*
 444                 * If object SHA1 is complete (len == 20), assume note object
 445                 * If object SHA1 is incomplete (len < 20), and current
 446                 * component consists of 2 hex chars, assume note subtree
 447                 */
 448                if (len <= GIT_SHA1_RAWSZ) {
 449                        type = PTR_TYPE_NOTE;
 450                        l = (struct leaf_node *)
 451                                xcalloc(1, sizeof(struct leaf_node));
 452                        oidcpy(&l->key_oid, &object_oid);
 453                        oidcpy(&l->val_oid, entry.oid);
 454                        if (len < GIT_SHA1_RAWSZ) {
 455                                if (!S_ISDIR(entry.mode) || path_len != 2)
 456                                        goto handle_non_note; /* not subtree */
 457                                l->key_oid.hash[KEY_INDEX] = (unsigned char) len;
 458                                type = PTR_TYPE_SUBTREE;
 459                        }
 460                        if (note_tree_insert(t, node, n, l, type,
 461                                             combine_notes_concatenate))
 462                                die("Failed to load %s %s into notes tree "
 463                                    "from %s",
 464                                    type == PTR_TYPE_NOTE ? "note" : "subtree",
 465                                    oid_to_hex(&l->key_oid), t->ref);
 466                }
 467                continue;
 468
 469handle_non_note:
 470                /*
 471                 * Determine full path for this non-note entry:
 472                 * The filename is already found in entry.path, but the
 473                 * directory part of the path must be deduced from the subtree
 474                 * containing this entry. We assume here that the overall notes
 475                 * tree follows a strict byte-based progressive fanout
 476                 * structure (i.e. using 2/38, 2/2/36, etc. fanouts, and not
 477                 * e.g. 4/36 fanout). This means that if a non-note is found at
 478                 * path "dead/beef", the following code will register it as
 479                 * being found on "de/ad/beef".
 480                 * On the other hand, if you use such non-obvious non-note
 481                 * paths in the middle of a notes tree, you deserve what's
 482                 * coming to you ;). Note that for non-notes that are not
 483                 * SHA1-like at the top level, there will be no problems.
 484                 *
 485                 * To conclude, it is strongly advised to make sure non-notes
 486                 * have at least one non-hex character in the top-level path
 487                 * component.
 488                 */
 489                {
 490                        struct strbuf non_note_path = STRBUF_INIT;
 491                        const char *q = oid_to_hex(&subtree->key_oid);
 492                        int i;
 493                        for (i = 0; i < prefix_len; i++) {
 494                                strbuf_addch(&non_note_path, *q++);
 495                                strbuf_addch(&non_note_path, *q++);
 496                                strbuf_addch(&non_note_path, '/');
 497                        }
 498                        strbuf_addstr(&non_note_path, entry.path);
 499                        add_non_note(t, strbuf_detach(&non_note_path, NULL),
 500                                     entry.mode, entry.oid->hash);
 501                }
 502        }
 503        free(buf);
 504}
 505
 506/*
 507 * Determine optimal on-disk fanout for this part of the notes tree
 508 *
 509 * Given a (sub)tree and the level in the internal tree structure, determine
 510 * whether or not the given existing fanout should be expanded for this
 511 * (sub)tree.
 512 *
 513 * Values of the 'fanout' variable:
 514 * - 0: No fanout (all notes are stored directly in the root notes tree)
 515 * - 1: 2/38 fanout
 516 * - 2: 2/2/36 fanout
 517 * - 3: 2/2/2/34 fanout
 518 * etc.
 519 */
 520static unsigned char determine_fanout(struct int_node *tree, unsigned char n,
 521                unsigned char fanout)
 522{
 523        /*
 524         * The following is a simple heuristic that works well in practice:
 525         * For each even-numbered 16-tree level (remember that each on-disk
 526         * fanout level corresponds to _two_ 16-tree levels), peek at all 16
 527         * entries at that tree level. If all of them are either int_nodes or
 528         * subtree entries, then there are likely plenty of notes below this
 529         * level, so we return an incremented fanout.
 530         */
 531        unsigned int i;
 532        if ((n % 2) || (n > 2 * fanout))
 533                return fanout;
 534        for (i = 0; i < 16; i++) {
 535                switch (GET_PTR_TYPE(tree->a[i])) {
 536                case PTR_TYPE_SUBTREE:
 537                case PTR_TYPE_INTERNAL:
 538                        continue;
 539                default:
 540                        return fanout;
 541                }
 542        }
 543        return fanout + 1;
 544}
 545
 546/* hex SHA1 + 19 * '/' + NUL */
 547#define FANOUT_PATH_MAX GIT_SHA1_HEXSZ + FANOUT_PATH_SEPARATORS + 1
 548
 549static void construct_path_with_fanout(const unsigned char *sha1,
 550                unsigned char fanout, char *path)
 551{
 552        unsigned int i = 0, j = 0;
 553        const char *hex_sha1 = sha1_to_hex(sha1);
 554        assert(fanout < GIT_SHA1_RAWSZ);
 555        while (fanout) {
 556                path[i++] = hex_sha1[j++];
 557                path[i++] = hex_sha1[j++];
 558                path[i++] = '/';
 559                fanout--;
 560        }
 561        xsnprintf(path + i, FANOUT_PATH_MAX - i, "%s", hex_sha1 + j);
 562}
 563
 564static int for_each_note_helper(struct notes_tree *t, struct int_node *tree,
 565                unsigned char n, unsigned char fanout, int flags,
 566                each_note_fn fn, void *cb_data)
 567{
 568        unsigned int i;
 569        void *p;
 570        int ret = 0;
 571        struct leaf_node *l;
 572        static char path[FANOUT_PATH_MAX];
 573
 574        fanout = determine_fanout(tree, n, fanout);
 575        for (i = 0; i < 16; i++) {
 576redo:
 577                p = tree->a[i];
 578                switch (GET_PTR_TYPE(p)) {
 579                case PTR_TYPE_INTERNAL:
 580                        /* recurse into int_node */
 581                        ret = for_each_note_helper(t, CLR_PTR_TYPE(p), n + 1,
 582                                fanout, flags, fn, cb_data);
 583                        break;
 584                case PTR_TYPE_SUBTREE:
 585                        l = (struct leaf_node *) CLR_PTR_TYPE(p);
 586                        /*
 587                         * Subtree entries in the note tree represent parts of
 588                         * the note tree that have not yet been explored. There
 589                         * is a direct relationship between subtree entries at
 590                         * level 'n' in the tree, and the 'fanout' variable:
 591                         * Subtree entries at level 'n <= 2 * fanout' should be
 592                         * preserved, since they correspond exactly to a fanout
 593                         * directory in the on-disk structure. However, subtree
 594                         * entries at level 'n > 2 * fanout' should NOT be
 595                         * preserved, but rather consolidated into the above
 596                         * notes tree level. We achieve this by unconditionally
 597                         * unpacking subtree entries that exist below the
 598                         * threshold level at 'n = 2 * fanout'.
 599                         */
 600                        if (n <= 2 * fanout &&
 601                            flags & FOR_EACH_NOTE_YIELD_SUBTREES) {
 602                                /* invoke callback with subtree */
 603                                unsigned int path_len =
 604                                        l->key_oid.hash[KEY_INDEX] * 2 + fanout;
 605                                assert(path_len < FANOUT_PATH_MAX - 1);
 606                                construct_path_with_fanout(l->key_oid.hash,
 607                                                           fanout,
 608                                                           path);
 609                                /* Create trailing slash, if needed */
 610                                if (path[path_len - 1] != '/')
 611                                        path[path_len++] = '/';
 612                                path[path_len] = '\0';
 613                                ret = fn(&l->key_oid, &l->val_oid,
 614                                         path,
 615                                         cb_data);
 616                        }
 617                        if (n > fanout * 2 ||
 618                            !(flags & FOR_EACH_NOTE_DONT_UNPACK_SUBTREES)) {
 619                                /* unpack subtree and resume traversal */
 620                                tree->a[i] = NULL;
 621                                load_subtree(t, l, tree, n);
 622                                free(l);
 623                                goto redo;
 624                        }
 625                        break;
 626                case PTR_TYPE_NOTE:
 627                        l = (struct leaf_node *) CLR_PTR_TYPE(p);
 628                        construct_path_with_fanout(l->key_oid.hash, fanout,
 629                                                   path);
 630                        ret = fn(&l->key_oid, &l->val_oid, path,
 631                                 cb_data);
 632                        break;
 633                }
 634                if (ret)
 635                        return ret;
 636        }
 637        return 0;
 638}
 639
 640struct tree_write_stack {
 641        struct tree_write_stack *next;
 642        struct strbuf buf;
 643        char path[2]; /* path to subtree in next, if any */
 644};
 645
 646static inline int matches_tree_write_stack(struct tree_write_stack *tws,
 647                const char *full_path)
 648{
 649        return  full_path[0] == tws->path[0] &&
 650                full_path[1] == tws->path[1] &&
 651                full_path[2] == '/';
 652}
 653
 654static void write_tree_entry(struct strbuf *buf, unsigned int mode,
 655                const char *path, unsigned int path_len, const
 656                unsigned char *sha1)
 657{
 658        strbuf_addf(buf, "%o %.*s%c", mode, path_len, path, '\0');
 659        strbuf_add(buf, sha1, GIT_SHA1_RAWSZ);
 660}
 661
 662static void tree_write_stack_init_subtree(struct tree_write_stack *tws,
 663                const char *path)
 664{
 665        struct tree_write_stack *n;
 666        assert(!tws->next);
 667        assert(tws->path[0] == '\0' && tws->path[1] == '\0');
 668        n = (struct tree_write_stack *)
 669                xmalloc(sizeof(struct tree_write_stack));
 670        n->next = NULL;
 671        strbuf_init(&n->buf, 256 * (32 + GIT_SHA1_HEXSZ)); /* assume 256 entries per tree */
 672        n->path[0] = n->path[1] = '\0';
 673        tws->next = n;
 674        tws->path[0] = path[0];
 675        tws->path[1] = path[1];
 676}
 677
 678static int tree_write_stack_finish_subtree(struct tree_write_stack *tws)
 679{
 680        int ret;
 681        struct tree_write_stack *n = tws->next;
 682        struct object_id s;
 683        if (n) {
 684                ret = tree_write_stack_finish_subtree(n);
 685                if (ret)
 686                        return ret;
 687                ret = write_sha1_file(n->buf.buf, n->buf.len, tree_type, s.hash);
 688                if (ret)
 689                        return ret;
 690                strbuf_release(&n->buf);
 691                free(n);
 692                tws->next = NULL;
 693                write_tree_entry(&tws->buf, 040000, tws->path, 2, s.hash);
 694                tws->path[0] = tws->path[1] = '\0';
 695        }
 696        return 0;
 697}
 698
 699static int write_each_note_helper(struct tree_write_stack *tws,
 700                const char *path, unsigned int mode,
 701                const struct object_id *oid)
 702{
 703        size_t path_len = strlen(path);
 704        unsigned int n = 0;
 705        int ret;
 706
 707        /* Determine common part of tree write stack */
 708        while (tws && 3 * n < path_len &&
 709               matches_tree_write_stack(tws, path + 3 * n)) {
 710                n++;
 711                tws = tws->next;
 712        }
 713
 714        /* tws point to last matching tree_write_stack entry */
 715        ret = tree_write_stack_finish_subtree(tws);
 716        if (ret)
 717                return ret;
 718
 719        /* Start subtrees needed to satisfy path */
 720        while (3 * n + 2 < path_len && path[3 * n + 2] == '/') {
 721                tree_write_stack_init_subtree(tws, path + 3 * n);
 722                n++;
 723                tws = tws->next;
 724        }
 725
 726        /* There should be no more directory components in the given path */
 727        assert(memchr(path + 3 * n, '/', path_len - (3 * n)) == NULL);
 728
 729        /* Finally add given entry to the current tree object */
 730        write_tree_entry(&tws->buf, mode, path + 3 * n, path_len - (3 * n),
 731                         oid->hash);
 732
 733        return 0;
 734}
 735
 736struct write_each_note_data {
 737        struct tree_write_stack *root;
 738        struct non_note *next_non_note;
 739};
 740
 741static int write_each_non_note_until(const char *note_path,
 742                struct write_each_note_data *d)
 743{
 744        struct non_note *n = d->next_non_note;
 745        int cmp = 0, ret;
 746        while (n && (!note_path || (cmp = strcmp(n->path, note_path)) <= 0)) {
 747                if (note_path && cmp == 0)
 748                        ; /* do nothing, prefer note to non-note */
 749                else {
 750                        ret = write_each_note_helper(d->root, n->path, n->mode,
 751                                                     &n->oid);
 752                        if (ret)
 753                                return ret;
 754                }
 755                n = n->next;
 756        }
 757        d->next_non_note = n;
 758        return 0;
 759}
 760
 761static int write_each_note(const struct object_id *object_oid,
 762                const struct object_id *note_oid, char *note_path,
 763                void *cb_data)
 764{
 765        struct write_each_note_data *d =
 766                (struct write_each_note_data *) cb_data;
 767        size_t note_path_len = strlen(note_path);
 768        unsigned int mode = 0100644;
 769
 770        if (note_path[note_path_len - 1] == '/') {
 771                /* subtree entry */
 772                note_path_len--;
 773                note_path[note_path_len] = '\0';
 774                mode = 040000;
 775        }
 776        assert(note_path_len <= GIT_SHA1_HEXSZ + FANOUT_PATH_SEPARATORS);
 777
 778        /* Weave non-note entries into note entries */
 779        return  write_each_non_note_until(note_path, d) ||
 780                write_each_note_helper(d->root, note_path, mode, note_oid);
 781}
 782
 783struct note_delete_list {
 784        struct note_delete_list *next;
 785        const unsigned char *sha1;
 786};
 787
 788static int prune_notes_helper(const struct object_id *object_oid,
 789                const struct object_id *note_oid, char *note_path,
 790                void *cb_data)
 791{
 792        struct note_delete_list **l = (struct note_delete_list **) cb_data;
 793        struct note_delete_list *n;
 794
 795        if (has_object_file(object_oid))
 796                return 0; /* nothing to do for this note */
 797
 798        /* failed to find object => prune this note */
 799        n = (struct note_delete_list *) xmalloc(sizeof(*n));
 800        n->next = *l;
 801        n->sha1 = object_oid->hash;
 802        *l = n;
 803        return 0;
 804}
 805
 806int combine_notes_concatenate(unsigned char *cur_sha1,
 807                const unsigned char *new_sha1)
 808{
 809        char *cur_msg = NULL, *new_msg = NULL, *buf;
 810        unsigned long cur_len, new_len, buf_len;
 811        enum object_type cur_type, new_type;
 812        int ret;
 813
 814        /* read in both note blob objects */
 815        if (!is_null_sha1(new_sha1))
 816                new_msg = read_sha1_file(new_sha1, &new_type, &new_len);
 817        if (!new_msg || !new_len || new_type != OBJ_BLOB) {
 818                free(new_msg);
 819                return 0;
 820        }
 821        if (!is_null_sha1(cur_sha1))
 822                cur_msg = read_sha1_file(cur_sha1, &cur_type, &cur_len);
 823        if (!cur_msg || !cur_len || cur_type != OBJ_BLOB) {
 824                free(cur_msg);
 825                free(new_msg);
 826                hashcpy(cur_sha1, new_sha1);
 827                return 0;
 828        }
 829
 830        /* we will separate the notes by two newlines anyway */
 831        if (cur_msg[cur_len - 1] == '\n')
 832                cur_len--;
 833
 834        /* concatenate cur_msg and new_msg into buf */
 835        buf_len = cur_len + 2 + new_len;
 836        buf = (char *) xmalloc(buf_len);
 837        memcpy(buf, cur_msg, cur_len);
 838        buf[cur_len] = '\n';
 839        buf[cur_len + 1] = '\n';
 840        memcpy(buf + cur_len + 2, new_msg, new_len);
 841        free(cur_msg);
 842        free(new_msg);
 843
 844        /* create a new blob object from buf */
 845        ret = write_sha1_file(buf, buf_len, blob_type, cur_sha1);
 846        free(buf);
 847        return ret;
 848}
 849
 850int combine_notes_overwrite(unsigned char *cur_sha1,
 851                const unsigned char *new_sha1)
 852{
 853        hashcpy(cur_sha1, new_sha1);
 854        return 0;
 855}
 856
 857int combine_notes_ignore(unsigned char *cur_sha1,
 858                const unsigned char *new_sha1)
 859{
 860        return 0;
 861}
 862
 863/*
 864 * Add the lines from the named object to list, with trailing
 865 * newlines removed.
 866 */
 867static int string_list_add_note_lines(struct string_list *list,
 868                                      const unsigned char *sha1)
 869{
 870        char *data;
 871        unsigned long len;
 872        enum object_type t;
 873
 874        if (is_null_sha1(sha1))
 875                return 0;
 876
 877        /* read_sha1_file NUL-terminates */
 878        data = read_sha1_file(sha1, &t, &len);
 879        if (t != OBJ_BLOB || !data || !len) {
 880                free(data);
 881                return t != OBJ_BLOB || !data;
 882        }
 883
 884        /*
 885         * If the last line of the file is EOL-terminated, this will
 886         * add an empty string to the list.  But it will be removed
 887         * later, along with any empty strings that came from empty
 888         * lines within the file.
 889         */
 890        string_list_split(list, data, '\n', -1);
 891        free(data);
 892        return 0;
 893}
 894
 895static int string_list_join_lines_helper(struct string_list_item *item,
 896                                         void *cb_data)
 897{
 898        struct strbuf *buf = cb_data;
 899        strbuf_addstr(buf, item->string);
 900        strbuf_addch(buf, '\n');
 901        return 0;
 902}
 903
 904int combine_notes_cat_sort_uniq(unsigned char *cur_sha1,
 905                const unsigned char *new_sha1)
 906{
 907        struct string_list sort_uniq_list = STRING_LIST_INIT_DUP;
 908        struct strbuf buf = STRBUF_INIT;
 909        int ret = 1;
 910
 911        /* read both note blob objects into unique_lines */
 912        if (string_list_add_note_lines(&sort_uniq_list, cur_sha1))
 913                goto out;
 914        if (string_list_add_note_lines(&sort_uniq_list, new_sha1))
 915                goto out;
 916        string_list_remove_empty_items(&sort_uniq_list, 0);
 917        string_list_sort(&sort_uniq_list);
 918        string_list_remove_duplicates(&sort_uniq_list, 0);
 919
 920        /* create a new blob object from sort_uniq_list */
 921        if (for_each_string_list(&sort_uniq_list,
 922                                 string_list_join_lines_helper, &buf))
 923                goto out;
 924
 925        ret = write_sha1_file(buf.buf, buf.len, blob_type, cur_sha1);
 926
 927out:
 928        strbuf_release(&buf);
 929        string_list_clear(&sort_uniq_list, 0);
 930        return ret;
 931}
 932
 933static int string_list_add_one_ref(const char *refname, const struct object_id *oid,
 934                                   int flag, void *cb)
 935{
 936        struct string_list *refs = cb;
 937        if (!unsorted_string_list_has_string(refs, refname))
 938                string_list_append(refs, refname);
 939        return 0;
 940}
 941
 942/*
 943 * The list argument must have strdup_strings set on it.
 944 */
 945void string_list_add_refs_by_glob(struct string_list *list, const char *glob)
 946{
 947        assert(list->strdup_strings);
 948        if (has_glob_specials(glob)) {
 949                for_each_glob_ref(string_list_add_one_ref, glob, list);
 950        } else {
 951                struct object_id oid;
 952                if (get_oid(glob, &oid))
 953                        warning("notes ref %s is invalid", glob);
 954                if (!unsorted_string_list_has_string(list, glob))
 955                        string_list_append(list, glob);
 956        }
 957}
 958
 959void string_list_add_refs_from_colon_sep(struct string_list *list,
 960                                         const char *globs)
 961{
 962        struct string_list split = STRING_LIST_INIT_NODUP;
 963        char *globs_copy = xstrdup(globs);
 964        int i;
 965
 966        string_list_split_in_place(&split, globs_copy, ':', -1);
 967        string_list_remove_empty_items(&split, 0);
 968
 969        for (i = 0; i < split.nr; i++)
 970                string_list_add_refs_by_glob(list, split.items[i].string);
 971
 972        string_list_clear(&split, 0);
 973        free(globs_copy);
 974}
 975
 976static int notes_display_config(const char *k, const char *v, void *cb)
 977{
 978        int *load_refs = cb;
 979
 980        if (*load_refs && !strcmp(k, "notes.displayref")) {
 981                if (!v)
 982                        config_error_nonbool(k);
 983                string_list_add_refs_by_glob(&display_notes_refs, v);
 984        }
 985
 986        return 0;
 987}
 988
 989const char *default_notes_ref(void)
 990{
 991        const char *notes_ref = NULL;
 992        if (!notes_ref)
 993                notes_ref = getenv(GIT_NOTES_REF_ENVIRONMENT);
 994        if (!notes_ref)
 995                notes_ref = notes_ref_name; /* value of core.notesRef config */
 996        if (!notes_ref)
 997                notes_ref = GIT_NOTES_DEFAULT_REF;
 998        return notes_ref;
 999}
1000
1001void init_notes(struct notes_tree *t, const char *notes_ref,
1002                combine_notes_fn combine_notes, int flags)
1003{
1004        struct object_id oid, object_oid;
1005        unsigned mode;
1006        struct leaf_node root_tree;
1007
1008        if (!t)
1009                t = &default_notes_tree;
1010        assert(!t->initialized);
1011
1012        if (!notes_ref)
1013                notes_ref = default_notes_ref();
1014
1015        if (!combine_notes)
1016                combine_notes = combine_notes_concatenate;
1017
1018        t->root = (struct int_node *) xcalloc(1, sizeof(struct int_node));
1019        t->first_non_note = NULL;
1020        t->prev_non_note = NULL;
1021        t->ref = xstrdup_or_null(notes_ref);
1022        t->update_ref = (flags & NOTES_INIT_WRITABLE) ? t->ref : NULL;
1023        t->combine_notes = combine_notes;
1024        t->initialized = 1;
1025        t->dirty = 0;
1026
1027        if (flags & NOTES_INIT_EMPTY || !notes_ref ||
1028            get_sha1_treeish(notes_ref, object_oid.hash))
1029                return;
1030        if (flags & NOTES_INIT_WRITABLE && read_ref(notes_ref, object_oid.hash))
1031                die("Cannot use notes ref %s", notes_ref);
1032        if (get_tree_entry(object_oid.hash, "", oid.hash, &mode))
1033                die("Failed to read notes tree referenced by %s (%s)",
1034                    notes_ref, oid_to_hex(&object_oid));
1035
1036        oidclr(&root_tree.key_oid);
1037        oidcpy(&root_tree.val_oid, &oid);
1038        load_subtree(t, &root_tree, t->root, 0);
1039}
1040
1041struct notes_tree **load_notes_trees(struct string_list *refs, int flags)
1042{
1043        struct string_list_item *item;
1044        int counter = 0;
1045        struct notes_tree **trees;
1046        ALLOC_ARRAY(trees, refs->nr + 1);
1047        for_each_string_list_item(item, refs) {
1048                struct notes_tree *t = xcalloc(1, sizeof(struct notes_tree));
1049                init_notes(t, item->string, combine_notes_ignore, flags);
1050                trees[counter++] = t;
1051        }
1052        trees[counter] = NULL;
1053        return trees;
1054}
1055
1056void init_display_notes(struct display_notes_opt *opt)
1057{
1058        char *display_ref_env;
1059        int load_config_refs = 0;
1060        display_notes_refs.strdup_strings = 1;
1061
1062        assert(!display_notes_trees);
1063
1064        if (!opt || opt->use_default_notes > 0 ||
1065            (opt->use_default_notes == -1 && !opt->extra_notes_refs.nr)) {
1066                string_list_append(&display_notes_refs, default_notes_ref());
1067                display_ref_env = getenv(GIT_NOTES_DISPLAY_REF_ENVIRONMENT);
1068                if (display_ref_env) {
1069                        string_list_add_refs_from_colon_sep(&display_notes_refs,
1070                                                            display_ref_env);
1071                        load_config_refs = 0;
1072                } else
1073                        load_config_refs = 1;
1074        }
1075
1076        git_config(notes_display_config, &load_config_refs);
1077
1078        if (opt) {
1079                struct string_list_item *item;
1080                for_each_string_list_item(item, &opt->extra_notes_refs)
1081                        string_list_add_refs_by_glob(&display_notes_refs,
1082                                                     item->string);
1083        }
1084
1085        display_notes_trees = load_notes_trees(&display_notes_refs, 0);
1086        string_list_clear(&display_notes_refs, 0);
1087}
1088
1089int add_note(struct notes_tree *t, const struct object_id *object_oid,
1090                const struct object_id *note_oid, combine_notes_fn combine_notes)
1091{
1092        struct leaf_node *l;
1093
1094        if (!t)
1095                t = &default_notes_tree;
1096        assert(t->initialized);
1097        t->dirty = 1;
1098        if (!combine_notes)
1099                combine_notes = t->combine_notes;
1100        l = (struct leaf_node *) xmalloc(sizeof(struct leaf_node));
1101        oidcpy(&l->key_oid, object_oid);
1102        oidcpy(&l->val_oid, note_oid);
1103        return note_tree_insert(t, t->root, 0, l, PTR_TYPE_NOTE, combine_notes);
1104}
1105
1106int remove_note(struct notes_tree *t, const unsigned char *object_sha1)
1107{
1108        struct leaf_node l;
1109
1110        if (!t)
1111                t = &default_notes_tree;
1112        assert(t->initialized);
1113        hashcpy(l.key_oid.hash, object_sha1);
1114        oidclr(&l.val_oid);
1115        note_tree_remove(t, t->root, 0, &l);
1116        if (is_null_oid(&l.val_oid)) /* no note was removed */
1117                return 1;
1118        t->dirty = 1;
1119        return 0;
1120}
1121
1122const struct object_id *get_note(struct notes_tree *t,
1123                const struct object_id *oid)
1124{
1125        struct leaf_node *found;
1126
1127        if (!t)
1128                t = &default_notes_tree;
1129        assert(t->initialized);
1130        found = note_tree_find(t, t->root, 0, oid->hash);
1131        return found ? &found->val_oid : NULL;
1132}
1133
1134int for_each_note(struct notes_tree *t, int flags, each_note_fn fn,
1135                void *cb_data)
1136{
1137        if (!t)
1138                t = &default_notes_tree;
1139        assert(t->initialized);
1140        return for_each_note_helper(t, t->root, 0, 0, flags, fn, cb_data);
1141}
1142
1143int write_notes_tree(struct notes_tree *t, unsigned char *result)
1144{
1145        struct tree_write_stack root;
1146        struct write_each_note_data cb_data;
1147        int ret;
1148
1149        if (!t)
1150                t = &default_notes_tree;
1151        assert(t->initialized);
1152
1153        /* Prepare for traversal of current notes tree */
1154        root.next = NULL; /* last forward entry in list is grounded */
1155        strbuf_init(&root.buf, 256 * (32 + GIT_SHA1_HEXSZ)); /* assume 256 entries */
1156        root.path[0] = root.path[1] = '\0';
1157        cb_data.root = &root;
1158        cb_data.next_non_note = t->first_non_note;
1159
1160        /* Write tree objects representing current notes tree */
1161        ret = for_each_note(t, FOR_EACH_NOTE_DONT_UNPACK_SUBTREES |
1162                                FOR_EACH_NOTE_YIELD_SUBTREES,
1163                        write_each_note, &cb_data) ||
1164                write_each_non_note_until(NULL, &cb_data) ||
1165                tree_write_stack_finish_subtree(&root) ||
1166                write_sha1_file(root.buf.buf, root.buf.len, tree_type, result);
1167        strbuf_release(&root.buf);
1168        return ret;
1169}
1170
1171void prune_notes(struct notes_tree *t, int flags)
1172{
1173        struct note_delete_list *l = NULL;
1174
1175        if (!t)
1176                t = &default_notes_tree;
1177        assert(t->initialized);
1178
1179        for_each_note(t, 0, prune_notes_helper, &l);
1180
1181        while (l) {
1182                if (flags & NOTES_PRUNE_VERBOSE)
1183                        printf("%s\n", sha1_to_hex(l->sha1));
1184                if (!(flags & NOTES_PRUNE_DRYRUN))
1185                        remove_note(t, l->sha1);
1186                l = l->next;
1187        }
1188}
1189
1190void free_notes(struct notes_tree *t)
1191{
1192        if (!t)
1193                t = &default_notes_tree;
1194        if (t->root)
1195                note_tree_free(t->root);
1196        free(t->root);
1197        while (t->first_non_note) {
1198                t->prev_non_note = t->first_non_note->next;
1199                free(t->first_non_note->path);
1200                free(t->first_non_note);
1201                t->first_non_note = t->prev_non_note;
1202        }
1203        free(t->ref);
1204        memset(t, 0, sizeof(struct notes_tree));
1205}
1206
1207/*
1208 * Fill the given strbuf with the notes associated with the given object.
1209 *
1210 * If the given notes_tree structure is not initialized, it will be auto-
1211 * initialized to the default value (see documentation for init_notes() above).
1212 * If the given notes_tree is NULL, the internal/default notes_tree will be
1213 * used instead.
1214 *
1215 * (raw != 0) gives the %N userformat; otherwise, the note message is given
1216 * for human consumption.
1217 */
1218static void format_note(struct notes_tree *t, const struct object_id *object_oid,
1219                        struct strbuf *sb, const char *output_encoding, int raw)
1220{
1221        static const char utf8[] = "utf-8";
1222        const struct object_id *oid;
1223        char *msg, *msg_p;
1224        unsigned long linelen, msglen;
1225        enum object_type type;
1226
1227        if (!t)
1228                t = &default_notes_tree;
1229        if (!t->initialized)
1230                init_notes(t, NULL, NULL, 0);
1231
1232        oid = get_note(t, object_oid);
1233        if (!oid)
1234                return;
1235
1236        if (!(msg = read_sha1_file(oid->hash, &type, &msglen)) || type != OBJ_BLOB) {
1237                free(msg);
1238                return;
1239        }
1240
1241        if (output_encoding && *output_encoding &&
1242            !is_encoding_utf8(output_encoding)) {
1243                char *reencoded = reencode_string(msg, output_encoding, utf8);
1244                if (reencoded) {
1245                        free(msg);
1246                        msg = reencoded;
1247                        msglen = strlen(msg);
1248                }
1249        }
1250
1251        /* we will end the annotation by a newline anyway */
1252        if (msglen && msg[msglen - 1] == '\n')
1253                msglen--;
1254
1255        if (!raw) {
1256                const char *ref = t->ref;
1257                if (!ref || !strcmp(ref, GIT_NOTES_DEFAULT_REF)) {
1258                        strbuf_addstr(sb, "\nNotes:\n");
1259                } else {
1260                        if (starts_with(ref, "refs/"))
1261                                ref += 5;
1262                        if (starts_with(ref, "notes/"))
1263                                ref += 6;
1264                        strbuf_addf(sb, "\nNotes (%s):\n", ref);
1265                }
1266        }
1267
1268        for (msg_p = msg; msg_p < msg + msglen; msg_p += linelen + 1) {
1269                linelen = strchrnul(msg_p, '\n') - msg_p;
1270
1271                if (!raw)
1272                        strbuf_addstr(sb, "    ");
1273                strbuf_add(sb, msg_p, linelen);
1274                strbuf_addch(sb, '\n');
1275        }
1276
1277        free(msg);
1278}
1279
1280void format_display_notes(const struct object_id *object_oid,
1281                          struct strbuf *sb, const char *output_encoding, int raw)
1282{
1283        int i;
1284        assert(display_notes_trees);
1285        for (i = 0; display_notes_trees[i]; i++)
1286                format_note(display_notes_trees[i], object_oid, sb,
1287                            output_encoding, raw);
1288}
1289
1290int copy_note(struct notes_tree *t,
1291              const struct object_id *from_obj, const struct object_id *to_obj,
1292              int force, combine_notes_fn combine_notes)
1293{
1294        const struct object_id *note = get_note(t, from_obj);
1295        const struct object_id *existing_note = get_note(t, to_obj);
1296
1297        if (!force && existing_note)
1298                return 1;
1299
1300        if (note)
1301                return add_note(t, to_obj, note, combine_notes);
1302        else if (existing_note)
1303                return add_note(t, to_obj, &null_oid, combine_notes);
1304
1305        return 0;
1306}
1307
1308void expand_notes_ref(struct strbuf *sb)
1309{
1310        if (starts_with(sb->buf, "refs/notes/"))
1311                return; /* we're happy */
1312        else if (starts_with(sb->buf, "notes/"))
1313                strbuf_insert(sb, 0, "refs/", 5);
1314        else
1315                strbuf_insert(sb, 0, "refs/notes/", 11);
1316}
1317
1318void expand_loose_notes_ref(struct strbuf *sb)
1319{
1320        struct object_id object;
1321
1322        if (get_oid(sb->buf, &object)) {
1323                /* fallback to expand_notes_ref */
1324                expand_notes_ref(sb);
1325        }
1326}