notes.h/c: Allow combine_notes functions to remove notes
[git/git.git] / notes.c
CommitLineData
a97a7468 1#include "cache.h"
a97a7468 2#include "notes.h"
73f464b5 3#include "blob.h"
61a7cca0 4#include "tree.h"
a97a7468
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5#include "utf8.h"
6#include "strbuf.h"
fd53c9eb 7#include "tree-walk.h"
894a9d33
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8#include "string-list.h"
9#include "refs.h"
fd53c9eb 10
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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];
fd53c9eb
JS
25};
26
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JH
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).
a7e7eff6 30 * As a note entry, the key is the SHA1 of the referenced object, and the
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JH
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
a7e7eff6 33 * referenced object, using the last byte of the key to store the length of
23123aec
JH
34 * the prefix. The value is the SHA1 of the tree object containing the notes
35 * subtree.
36 */
37struct leaf_node {
38 unsigned char key_sha1[20];
39 unsigned char val_sha1[20];
fd53c9eb 40};
a97a7468 41
851c2b37
JH
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 unsigned char sha1[20];
55};
56
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57#define PTR_TYPE_NULL 0
58#define PTR_TYPE_INTERNAL 1
59#define PTR_TYPE_NOTE 2
60#define PTR_TYPE_SUBTREE 3
fd53c9eb 61
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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)))
fd53c9eb 65
1ec666b0 66#define GET_NIBBLE(n, sha1) (((sha1[(n) >> 1]) >> ((~(n) & 0x01) << 2)) & 0x0f)
fd53c9eb 67
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68#define SUBTREE_SHA1_PREFIXCMP(key_sha1, subtree_sha1) \
69 (memcmp(key_sha1, subtree_sha1, subtree_sha1[19]))
fd53c9eb 70
cd305392 71struct notes_tree default_notes_tree;
23123aec 72
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73static struct string_list display_notes_refs;
74static struct notes_tree **display_notes_trees;
75
851c2b37
JH
76static void load_subtree(struct notes_tree *t, struct leaf_node *subtree,
77 struct int_node *node, unsigned int n);
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78
79/*
ef8db638 80 * Search the tree until the appropriate location for the given key is found:
23123aec 81 * 1. Start at the root node, with n = 0
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82 * 2. If a[0] at the current level is a matching subtree entry, unpack that
83 * subtree entry and remove it; restart search at the current level.
84 * 3. Use the nth nibble of the key as an index into a:
85 * - If a[n] is an int_node, recurse from #2 into that node and increment n
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86 * - If a matching subtree entry, unpack that subtree entry (and remove it);
87 * restart search at the current level.
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88 * - Otherwise, we have found one of the following:
89 * - a subtree entry which does not match the key
90 * - a note entry which may or may not match the key
91 * - an unused leaf node (NULL)
92 * In any case, set *tree and *n, and return pointer to the tree location.
23123aec 93 */
851c2b37 94static void **note_tree_search(struct notes_tree *t, struct int_node **tree,
ef8db638 95 unsigned char *n, const unsigned char *key_sha1)
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96{
97 struct leaf_node *l;
ef8db638
JH
98 unsigned char i;
99 void *p = (*tree)->a[0];
23123aec 100
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101 if (GET_PTR_TYPE(p) == PTR_TYPE_SUBTREE) {
102 l = (struct leaf_node *) CLR_PTR_TYPE(p);
103 if (!SUBTREE_SHA1_PREFIXCMP(key_sha1, l->key_sha1)) {
104 /* unpack tree and resume search */
105 (*tree)->a[0] = NULL;
851c2b37 106 load_subtree(t, l, *tree, *n);
ef8db638 107 free(l);
851c2b37 108 return note_tree_search(t, tree, n, key_sha1);
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JH
109 }
110 }
111
112 i = GET_NIBBLE(*n, key_sha1);
113 p = (*tree)->a[i];
0ab1faae 114 switch (GET_PTR_TYPE(p)) {
23123aec 115 case PTR_TYPE_INTERNAL:
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116 *tree = CLR_PTR_TYPE(p);
117 (*n)++;
851c2b37 118 return note_tree_search(t, tree, n, key_sha1);
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119 case PTR_TYPE_SUBTREE:
120 l = (struct leaf_node *) CLR_PTR_TYPE(p);
121 if (!SUBTREE_SHA1_PREFIXCMP(key_sha1, l->key_sha1)) {
122 /* unpack tree and resume search */
ef8db638 123 (*tree)->a[i] = NULL;
851c2b37 124 load_subtree(t, l, *tree, *n);
23123aec 125 free(l);
851c2b37 126 return note_tree_search(t, tree, n, key_sha1);
23123aec 127 }
ef8db638 128 /* fall through */
23123aec 129 default:
ef8db638 130 return &((*tree)->a[i]);
fd53c9eb 131 }
ef8db638 132}
23123aec 133
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JH
134/*
135 * To find a leaf_node:
136 * Search to the tree location appropriate for the given key:
137 * If a note entry with matching key, return the note entry, else return NULL.
138 */
851c2b37
JH
139static struct leaf_node *note_tree_find(struct notes_tree *t,
140 struct int_node *tree, unsigned char n,
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JH
141 const unsigned char *key_sha1)
142{
851c2b37 143 void **p = note_tree_search(t, &tree, &n, key_sha1);
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144 if (GET_PTR_TYPE(*p) == PTR_TYPE_NOTE) {
145 struct leaf_node *l = (struct leaf_node *) CLR_PTR_TYPE(*p);
146 if (!hashcmp(key_sha1, l->key_sha1))
147 return l;
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148 }
149 return NULL;
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JS
150}
151
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JH
152/*
153 * How to consolidate an int_node:
154 * If there are > 1 non-NULL entries, give up and return non-zero.
155 * Otherwise replace the int_node at the given index in the given parent node
156 * with the only entry (or a NULL entry if no entries) from the given tree,
157 * and return 0.
158 */
159static int note_tree_consolidate(struct int_node *tree,
160 struct int_node *parent, unsigned char index)
161{
162 unsigned int i;
163 void *p = NULL;
164
165 assert(tree && parent);
166 assert(CLR_PTR_TYPE(parent->a[index]) == tree);
167
168 for (i = 0; i < 16; i++) {
169 if (GET_PTR_TYPE(tree->a[i]) != PTR_TYPE_NULL) {
170 if (p) /* more than one entry */
171 return -2;
172 p = tree->a[i];
173 }
174 }
175
176 /* replace tree with p in parent[index] */
177 parent->a[index] = p;
178 free(tree);
179 return 0;
180}
181
182/*
183 * To remove a leaf_node:
184 * Search to the tree location appropriate for the given leaf_node's key:
185 * - If location does not hold a matching entry, abort and do nothing.
186 * - Replace the matching leaf_node with a NULL entry (and free the leaf_node).
187 * - Consolidate int_nodes repeatedly, while walking up the tree towards root.
188 */
189static void note_tree_remove(struct notes_tree *t, struct int_node *tree,
190 unsigned char n, struct leaf_node *entry)
191{
192 struct leaf_node *l;
193 struct int_node *parent_stack[20];
194 unsigned char i, j;
195 void **p = note_tree_search(t, &tree, &n, entry->key_sha1);
196
197 assert(GET_PTR_TYPE(entry) == 0); /* no type bits set */
198 if (GET_PTR_TYPE(*p) != PTR_TYPE_NOTE)
199 return; /* type mismatch, nothing to remove */
200 l = (struct leaf_node *) CLR_PTR_TYPE(*p);
201 if (hashcmp(l->key_sha1, entry->key_sha1))
202 return; /* key mismatch, nothing to remove */
203
204 /* we have found a matching entry */
205 free(l);
206 *p = SET_PTR_TYPE(NULL, PTR_TYPE_NULL);
207
208 /* consolidate this tree level, and parent levels, if possible */
209 if (!n)
210 return; /* cannot consolidate top level */
211 /* first, build stack of ancestors between root and current node */
212 parent_stack[0] = t->root;
213 for (i = 0; i < n; i++) {
214 j = GET_NIBBLE(i, entry->key_sha1);
215 parent_stack[i + 1] = CLR_PTR_TYPE(parent_stack[i]->a[j]);
216 }
217 assert(i == n && parent_stack[i] == tree);
218 /* next, unwind stack until note_tree_consolidate() is done */
219 while (i > 0 &&
220 !note_tree_consolidate(parent_stack[i], parent_stack[i - 1],
221 GET_NIBBLE(i - 1, entry->key_sha1)))
222 i--;
223}
224
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225/*
226 * To insert a leaf_node:
ef8db638
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227 * Search to the tree location appropriate for the given leaf_node's key:
228 * - If location is unused (NULL), store the tweaked pointer directly there
229 * - If location holds a note entry that matches the note-to-be-inserted, then
73f464b5 230 * combine the two notes (by calling the given combine_notes function).
ef8db638
JH
231 * - If location holds a note entry that matches the subtree-to-be-inserted,
232 * then unpack the subtree-to-be-inserted into the location.
233 * - If location holds a matching subtree entry, unpack the subtree at that
234 * location, and restart the insert operation from that level.
235 * - Else, create a new int_node, holding both the node-at-location and the
236 * node-to-be-inserted, and store the new int_node into the location.
23123aec 237 */
851c2b37
JH
238static void note_tree_insert(struct notes_tree *t, struct int_node *tree,
239 unsigned char n, struct leaf_node *entry, unsigned char type,
73f464b5 240 combine_notes_fn combine_notes)
fd53c9eb 241{
23123aec 242 struct int_node *new_node;
ef8db638 243 struct leaf_node *l;
851c2b37 244 void **p = note_tree_search(t, &tree, &n, entry->key_sha1);
ef8db638
JH
245
246 assert(GET_PTR_TYPE(entry) == 0); /* no type bits set */
247 l = (struct leaf_node *) CLR_PTR_TYPE(*p);
0ab1faae 248 switch (GET_PTR_TYPE(*p)) {
23123aec 249 case PTR_TYPE_NULL:
ef8db638 250 assert(!*p);
e2656c82
JH
251 if (is_null_sha1(entry->val_sha1))
252 free(entry);
253 else
254 *p = SET_PTR_TYPE(entry, type);
ef8db638
JH
255 return;
256 case PTR_TYPE_NOTE:
257 switch (type) {
258 case PTR_TYPE_NOTE:
259 if (!hashcmp(l->key_sha1, entry->key_sha1)) {
260 /* skip concatenation if l == entry */
261 if (!hashcmp(l->val_sha1, entry->val_sha1))
262 return;
263
73f464b5
JH
264 if (combine_notes(l->val_sha1, entry->val_sha1))
265 die("failed to combine notes %s and %s"
266 " for object %s",
ef8db638 267 sha1_to_hex(l->val_sha1),
73f464b5 268 sha1_to_hex(entry->val_sha1),
ef8db638 269 sha1_to_hex(l->key_sha1));
e2656c82
JH
270
271 if (is_null_sha1(l->val_sha1))
272 note_tree_remove(t, tree, n, entry);
ef8db638
JH
273 free(entry);
274 return;
275 }
276 break;
277 case PTR_TYPE_SUBTREE:
278 if (!SUBTREE_SHA1_PREFIXCMP(l->key_sha1,
279 entry->key_sha1)) {
280 /* unpack 'entry' */
851c2b37 281 load_subtree(t, entry, tree, n);
ef8db638
JH
282 free(entry);
283 return;
284 }
285 break;
286 }
287 break;
288 case PTR_TYPE_SUBTREE:
289 if (!SUBTREE_SHA1_PREFIXCMP(entry->key_sha1, l->key_sha1)) {
290 /* unpack 'l' and restart insert */
291 *p = NULL;
851c2b37 292 load_subtree(t, l, tree, n);
ef8db638 293 free(l);
851c2b37
JH
294 note_tree_insert(t, tree, n, entry, type,
295 combine_notes);
ef8db638 296 return;
23123aec 297 }
ef8db638 298 break;
fd53c9eb 299 }
ef8db638
JH
300
301 /* non-matching leaf_node */
302 assert(GET_PTR_TYPE(*p) == PTR_TYPE_NOTE ||
303 GET_PTR_TYPE(*p) == PTR_TYPE_SUBTREE);
e2656c82
JH
304 if (is_null_sha1(entry->val_sha1)) { /* skip insertion of empty note */
305 free(entry);
306 return;
307 }
ef8db638 308 new_node = (struct int_node *) xcalloc(sizeof(struct int_node), 1);
851c2b37
JH
309 note_tree_insert(t, new_node, n + 1, l, GET_PTR_TYPE(*p),
310 combine_notes);
ef8db638 311 *p = SET_PTR_TYPE(new_node, PTR_TYPE_INTERNAL);
851c2b37 312 note_tree_insert(t, new_node, n + 1, entry, type, combine_notes);
23123aec 313}
fd53c9eb 314
23123aec
JH
315/* Free the entire notes data contained in the given tree */
316static void note_tree_free(struct int_node *tree)
317{
318 unsigned int i;
319 for (i = 0; i < 16; i++) {
320 void *p = tree->a[i];
0ab1faae 321 switch (GET_PTR_TYPE(p)) {
23123aec
JH
322 case PTR_TYPE_INTERNAL:
323 note_tree_free(CLR_PTR_TYPE(p));
324 /* fall through */
325 case PTR_TYPE_NOTE:
326 case PTR_TYPE_SUBTREE:
327 free(CLR_PTR_TYPE(p));
328 }
fd53c9eb 329 }
23123aec 330}
fd53c9eb 331
23123aec
JH
332/*
333 * Convert a partial SHA1 hex string to the corresponding partial SHA1 value.
334 * - hex - Partial SHA1 segment in ASCII hex format
335 * - hex_len - Length of above segment. Must be multiple of 2 between 0 and 40
336 * - sha1 - Partial SHA1 value is written here
337 * - sha1_len - Max #bytes to store in sha1, Must be >= hex_len / 2, and < 20
0ab1faae 338 * Returns -1 on error (invalid arguments or invalid SHA1 (not in hex format)).
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JH
339 * Otherwise, returns number of bytes written to sha1 (i.e. hex_len / 2).
340 * Pads sha1 with NULs up to sha1_len (not included in returned length).
341 */
342static int get_sha1_hex_segment(const char *hex, unsigned int hex_len,
343 unsigned char *sha1, unsigned int sha1_len)
344{
345 unsigned int i, len = hex_len >> 1;
346 if (hex_len % 2 != 0 || len > sha1_len)
347 return -1;
348 for (i = 0; i < len; i++) {
349 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
350 if (val & ~0xff)
351 return -1;
352 *sha1++ = val;
353 hex += 2;
354 }
355 for (; i < sha1_len; i++)
356 *sha1++ = 0;
357 return len;
fd53c9eb
JS
358}
359
851c2b37
JH
360static int non_note_cmp(const struct non_note *a, const struct non_note *b)
361{
362 return strcmp(a->path, b->path);
363}
364
365static void add_non_note(struct notes_tree *t, const char *path,
366 unsigned int mode, const unsigned char *sha1)
367{
368 struct non_note *p = t->prev_non_note, *n;
369 n = (struct non_note *) xmalloc(sizeof(struct non_note));
370 n->next = NULL;
371 n->path = xstrdup(path);
372 n->mode = mode;
373 hashcpy(n->sha1, sha1);
374 t->prev_non_note = n;
375
376 if (!t->first_non_note) {
377 t->first_non_note = n;
378 return;
379 }
380
381 if (non_note_cmp(p, n) < 0)
382 ; /* do nothing */
383 else if (non_note_cmp(t->first_non_note, n) <= 0)
384 p = t->first_non_note;
385 else {
386 /* n sorts before t->first_non_note */
387 n->next = t->first_non_note;
388 t->first_non_note = n;
389 return;
390 }
391
392 /* n sorts equal or after p */
393 while (p->next && non_note_cmp(p->next, n) <= 0)
394 p = p->next;
395
396 if (non_note_cmp(p, n) == 0) { /* n ~= p; overwrite p with n */
397 assert(strcmp(p->path, n->path) == 0);
398 p->mode = n->mode;
399 hashcpy(p->sha1, n->sha1);
400 free(n);
401 t->prev_non_note = p;
402 return;
403 }
404
405 /* n sorts between p and p->next */
406 n->next = p->next;
407 p->next = n;
408}
409
410static void load_subtree(struct notes_tree *t, struct leaf_node *subtree,
411 struct int_node *node, unsigned int n)
fd53c9eb 412{
a7e7eff6 413 unsigned char object_sha1[20];
23123aec 414 unsigned int prefix_len;
23123aec 415 void *buf;
fd53c9eb
JS
416 struct tree_desc desc;
417 struct name_entry entry;
851c2b37
JH
418 int len, path_len;
419 unsigned char type;
420 struct leaf_node *l;
23123aec
JH
421
422 buf = fill_tree_descriptor(&desc, subtree->val_sha1);
423 if (!buf)
424 die("Could not read %s for notes-index",
425 sha1_to_hex(subtree->val_sha1));
426
427 prefix_len = subtree->key_sha1[19];
428 assert(prefix_len * 2 >= n);
a7e7eff6 429 memcpy(object_sha1, subtree->key_sha1, prefix_len);
23123aec 430 while (tree_entry(&desc, &entry)) {
851c2b37
JH
431 path_len = strlen(entry.path);
432 len = get_sha1_hex_segment(entry.path, path_len,
a7e7eff6 433 object_sha1 + prefix_len, 20 - prefix_len);
23123aec 434 if (len < 0)
851c2b37 435 goto handle_non_note; /* entry.path is not a SHA1 */
23123aec
JH
436 len += prefix_len;
437
438 /*
a7e7eff6 439 * If object SHA1 is complete (len == 20), assume note object
851c2b37
JH
440 * If object SHA1 is incomplete (len < 20), and current
441 * component consists of 2 hex chars, assume note subtree
23123aec
JH
442 */
443 if (len <= 20) {
851c2b37
JH
444 type = PTR_TYPE_NOTE;
445 l = (struct leaf_node *)
23123aec 446 xcalloc(sizeof(struct leaf_node), 1);
a7e7eff6 447 hashcpy(l->key_sha1, object_sha1);
23123aec
JH
448 hashcpy(l->val_sha1, entry.sha1);
449 if (len < 20) {
851c2b37
JH
450 if (!S_ISDIR(entry.mode) || path_len != 2)
451 goto handle_non_note; /* not subtree */
23123aec
JH
452 l->key_sha1[19] = (unsigned char) len;
453 type = PTR_TYPE_SUBTREE;
454 }
851c2b37 455 note_tree_insert(t, node, n, l, type,
73f464b5 456 combine_notes_concatenate);
23123aec 457 }
851c2b37
JH
458 continue;
459
460handle_non_note:
461 /*
462 * Determine full path for this non-note entry:
463 * The filename is already found in entry.path, but the
464 * directory part of the path must be deduced from the subtree
465 * containing this entry. We assume here that the overall notes
466 * tree follows a strict byte-based progressive fanout
467 * structure (i.e. using 2/38, 2/2/36, etc. fanouts, and not
468 * e.g. 4/36 fanout). This means that if a non-note is found at
469 * path "dead/beef", the following code will register it as
470 * being found on "de/ad/beef".
471 * On the other hand, if you use such non-obvious non-note
472 * paths in the middle of a notes tree, you deserve what's
473 * coming to you ;). Note that for non-notes that are not
474 * SHA1-like at the top level, there will be no problems.
475 *
476 * To conclude, it is strongly advised to make sure non-notes
477 * have at least one non-hex character in the top-level path
478 * component.
479 */
480 {
481 char non_note_path[PATH_MAX];
482 char *p = non_note_path;
483 const char *q = sha1_to_hex(subtree->key_sha1);
484 int i;
485 for (i = 0; i < prefix_len; i++) {
486 *p++ = *q++;
487 *p++ = *q++;
488 *p++ = '/';
489 }
490 strcpy(p, entry.path);
491 add_non_note(t, non_note_path, entry.mode, entry.sha1);
492 }
23123aec
JH
493 }
494 free(buf);
495}
496
73f77b90
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497/*
498 * Determine optimal on-disk fanout for this part of the notes tree
499 *
500 * Given a (sub)tree and the level in the internal tree structure, determine
501 * whether or not the given existing fanout should be expanded for this
502 * (sub)tree.
503 *
504 * Values of the 'fanout' variable:
505 * - 0: No fanout (all notes are stored directly in the root notes tree)
506 * - 1: 2/38 fanout
507 * - 2: 2/2/36 fanout
508 * - 3: 2/2/2/34 fanout
509 * etc.
510 */
511static unsigned char determine_fanout(struct int_node *tree, unsigned char n,
512 unsigned char fanout)
513{
514 /*
515 * The following is a simple heuristic that works well in practice:
516 * For each even-numbered 16-tree level (remember that each on-disk
517 * fanout level corresponds to _two_ 16-tree levels), peek at all 16
518 * entries at that tree level. If all of them are either int_nodes or
519 * subtree entries, then there are likely plenty of notes below this
520 * level, so we return an incremented fanout.
521 */
522 unsigned int i;
523 if ((n % 2) || (n > 2 * fanout))
524 return fanout;
525 for (i = 0; i < 16; i++) {
526 switch (GET_PTR_TYPE(tree->a[i])) {
527 case PTR_TYPE_SUBTREE:
528 case PTR_TYPE_INTERNAL:
529 continue;
530 default:
531 return fanout;
532 }
533 }
534 return fanout + 1;
535}
536
537static void construct_path_with_fanout(const unsigned char *sha1,
538 unsigned char fanout, char *path)
539{
540 unsigned int i = 0, j = 0;
541 const char *hex_sha1 = sha1_to_hex(sha1);
542 assert(fanout < 20);
543 while (fanout) {
544 path[i++] = hex_sha1[j++];
545 path[i++] = hex_sha1[j++];
546 path[i++] = '/';
547 fanout--;
548 }
549 strcpy(path + i, hex_sha1 + j);
550}
551
851c2b37
JH
552static int for_each_note_helper(struct notes_tree *t, struct int_node *tree,
553 unsigned char n, unsigned char fanout, int flags,
554 each_note_fn fn, void *cb_data)
73f77b90
JH
555{
556 unsigned int i;
557 void *p;
558 int ret = 0;
559 struct leaf_node *l;
560 static char path[40 + 19 + 1]; /* hex SHA1 + 19 * '/' + NUL */
561
562 fanout = determine_fanout(tree, n, fanout);
563 for (i = 0; i < 16; i++) {
564redo:
565 p = tree->a[i];
566 switch (GET_PTR_TYPE(p)) {
567 case PTR_TYPE_INTERNAL:
568 /* recurse into int_node */
851c2b37 569 ret = for_each_note_helper(t, CLR_PTR_TYPE(p), n + 1,
73f77b90
JH
570 fanout, flags, fn, cb_data);
571 break;
572 case PTR_TYPE_SUBTREE:
573 l = (struct leaf_node *) CLR_PTR_TYPE(p);
574 /*
575 * Subtree entries in the note tree represent parts of
576 * the note tree that have not yet been explored. There
577 * is a direct relationship between subtree entries at
578 * level 'n' in the tree, and the 'fanout' variable:
579 * Subtree entries at level 'n <= 2 * fanout' should be
580 * preserved, since they correspond exactly to a fanout
581 * directory in the on-disk structure. However, subtree
582 * entries at level 'n > 2 * fanout' should NOT be
583 * preserved, but rather consolidated into the above
584 * notes tree level. We achieve this by unconditionally
585 * unpacking subtree entries that exist below the
586 * threshold level at 'n = 2 * fanout'.
587 */
588 if (n <= 2 * fanout &&
589 flags & FOR_EACH_NOTE_YIELD_SUBTREES) {
590 /* invoke callback with subtree */
591 unsigned int path_len =
592 l->key_sha1[19] * 2 + fanout;
593 assert(path_len < 40 + 19);
594 construct_path_with_fanout(l->key_sha1, fanout,
595 path);
596 /* Create trailing slash, if needed */
597 if (path[path_len - 1] != '/')
598 path[path_len++] = '/';
599 path[path_len] = '\0';
600 ret = fn(l->key_sha1, l->val_sha1, path,
601 cb_data);
602 }
603 if (n > fanout * 2 ||
604 !(flags & FOR_EACH_NOTE_DONT_UNPACK_SUBTREES)) {
605 /* unpack subtree and resume traversal */
606 tree->a[i] = NULL;
851c2b37 607 load_subtree(t, l, tree, n);
73f77b90
JH
608 free(l);
609 goto redo;
610 }
611 break;
612 case PTR_TYPE_NOTE:
613 l = (struct leaf_node *) CLR_PTR_TYPE(p);
614 construct_path_with_fanout(l->key_sha1, fanout, path);
615 ret = fn(l->key_sha1, l->val_sha1, path, cb_data);
616 break;
617 }
618 if (ret)
619 return ret;
620 }
621 return 0;
622}
623
61a7cca0
JH
624struct tree_write_stack {
625 struct tree_write_stack *next;
626 struct strbuf buf;
627 char path[2]; /* path to subtree in next, if any */
628};
629
630static inline int matches_tree_write_stack(struct tree_write_stack *tws,
631 const char *full_path)
632{
633 return full_path[0] == tws->path[0] &&
634 full_path[1] == tws->path[1] &&
635 full_path[2] == '/';
636}
637
638static void write_tree_entry(struct strbuf *buf, unsigned int mode,
639 const char *path, unsigned int path_len, const
640 unsigned char *sha1)
641{
c88f0cc7
JH
642 strbuf_addf(buf, "%o %.*s%c", mode, path_len, path, '\0');
643 strbuf_add(buf, sha1, 20);
61a7cca0
JH
644}
645
646static void tree_write_stack_init_subtree(struct tree_write_stack *tws,
647 const char *path)
648{
649 struct tree_write_stack *n;
650 assert(!tws->next);
651 assert(tws->path[0] == '\0' && tws->path[1] == '\0');
652 n = (struct tree_write_stack *)
653 xmalloc(sizeof(struct tree_write_stack));
654 n->next = NULL;
655 strbuf_init(&n->buf, 256 * (32 + 40)); /* assume 256 entries per tree */
656 n->path[0] = n->path[1] = '\0';
657 tws->next = n;
658 tws->path[0] = path[0];
659 tws->path[1] = path[1];
660}
661
662static int tree_write_stack_finish_subtree(struct tree_write_stack *tws)
663{
664 int ret;
665 struct tree_write_stack *n = tws->next;
666 unsigned char s[20];
667 if (n) {
668 ret = tree_write_stack_finish_subtree(n);
669 if (ret)
670 return ret;
671 ret = write_sha1_file(n->buf.buf, n->buf.len, tree_type, s);
672 if (ret)
673 return ret;
674 strbuf_release(&n->buf);
675 free(n);
676 tws->next = NULL;
677 write_tree_entry(&tws->buf, 040000, tws->path, 2, s);
678 tws->path[0] = tws->path[1] = '\0';
679 }
680 return 0;
681}
682
683static int write_each_note_helper(struct tree_write_stack *tws,
684 const char *path, unsigned int mode,
685 const unsigned char *sha1)
686{
687 size_t path_len = strlen(path);
688 unsigned int n = 0;
689 int ret;
690
691 /* Determine common part of tree write stack */
692 while (tws && 3 * n < path_len &&
693 matches_tree_write_stack(tws, path + 3 * n)) {
694 n++;
695 tws = tws->next;
696 }
697
698 /* tws point to last matching tree_write_stack entry */
699 ret = tree_write_stack_finish_subtree(tws);
700 if (ret)
701 return ret;
702
703 /* Start subtrees needed to satisfy path */
704 while (3 * n + 2 < path_len && path[3 * n + 2] == '/') {
705 tree_write_stack_init_subtree(tws, path + 3 * n);
706 n++;
707 tws = tws->next;
708 }
709
710 /* There should be no more directory components in the given path */
711 assert(memchr(path + 3 * n, '/', path_len - (3 * n)) == NULL);
712
713 /* Finally add given entry to the current tree object */
714 write_tree_entry(&tws->buf, mode, path + 3 * n, path_len - (3 * n),
715 sha1);
716
717 return 0;
718}
719
720struct write_each_note_data {
721 struct tree_write_stack *root;
851c2b37 722 struct non_note *next_non_note;
61a7cca0
JH
723};
724
851c2b37
JH
725static int write_each_non_note_until(const char *note_path,
726 struct write_each_note_data *d)
727{
728 struct non_note *n = d->next_non_note;
89fe121d 729 int cmp = 0, ret;
851c2b37
JH
730 while (n && (!note_path || (cmp = strcmp(n->path, note_path)) <= 0)) {
731 if (note_path && cmp == 0)
732 ; /* do nothing, prefer note to non-note */
733 else {
734 ret = write_each_note_helper(d->root, n->path, n->mode,
735 n->sha1);
736 if (ret)
737 return ret;
738 }
739 n = n->next;
740 }
741 d->next_non_note = n;
742 return 0;
743}
744
61a7cca0
JH
745static int write_each_note(const unsigned char *object_sha1,
746 const unsigned char *note_sha1, char *note_path,
747 void *cb_data)
748{
749 struct write_each_note_data *d =
750 (struct write_each_note_data *) cb_data;
751 size_t note_path_len = strlen(note_path);
752 unsigned int mode = 0100644;
753
754 if (note_path[note_path_len - 1] == '/') {
755 /* subtree entry */
756 note_path_len--;
757 note_path[note_path_len] = '\0';
758 mode = 040000;
759 }
760 assert(note_path_len <= 40 + 19);
761
851c2b37
JH
762 /* Weave non-note entries into note entries */
763 return write_each_non_note_until(note_path, d) ||
764 write_each_note_helper(d->root, note_path, mode, note_sha1);
61a7cca0
JH
765}
766
00fbe636
JH
767struct note_delete_list {
768 struct note_delete_list *next;
769 const unsigned char *sha1;
770};
771
772static int prune_notes_helper(const unsigned char *object_sha1,
773 const unsigned char *note_sha1, char *note_path,
774 void *cb_data)
775{
776 struct note_delete_list **l = (struct note_delete_list **) cb_data;
777 struct note_delete_list *n;
778
779 if (has_sha1_file(object_sha1))
780 return 0; /* nothing to do for this note */
781
782 /* failed to find object => prune this note */
783 n = (struct note_delete_list *) xmalloc(sizeof(*n));
784 n->next = *l;
785 n->sha1 = object_sha1;
786 *l = n;
787 return 0;
788}
789
73f464b5
JH
790int combine_notes_concatenate(unsigned char *cur_sha1,
791 const unsigned char *new_sha1)
792{
793 char *cur_msg = NULL, *new_msg = NULL, *buf;
794 unsigned long cur_len, new_len, buf_len;
795 enum object_type cur_type, new_type;
796 int ret;
797
798 /* read in both note blob objects */
799 if (!is_null_sha1(new_sha1))
800 new_msg = read_sha1_file(new_sha1, &new_type, &new_len);
801 if (!new_msg || !new_len || new_type != OBJ_BLOB) {
802 free(new_msg);
803 return 0;
804 }
805 if (!is_null_sha1(cur_sha1))
806 cur_msg = read_sha1_file(cur_sha1, &cur_type, &cur_len);
807 if (!cur_msg || !cur_len || cur_type != OBJ_BLOB) {
808 free(cur_msg);
809 free(new_msg);
810 hashcpy(cur_sha1, new_sha1);
811 return 0;
812 }
813
814 /* we will separate the notes by a newline anyway */
815 if (cur_msg[cur_len - 1] == '\n')
816 cur_len--;
817
818 /* concatenate cur_msg and new_msg into buf */
819 buf_len = cur_len + 1 + new_len;
820 buf = (char *) xmalloc(buf_len);
821 memcpy(buf, cur_msg, cur_len);
822 buf[cur_len] = '\n';
823 memcpy(buf + cur_len + 1, new_msg, new_len);
824 free(cur_msg);
825 free(new_msg);
826
827 /* create a new blob object from buf */
828 ret = write_sha1_file(buf, buf_len, blob_type, cur_sha1);
829 free(buf);
830 return ret;
831}
832
833int combine_notes_overwrite(unsigned char *cur_sha1,
834 const unsigned char *new_sha1)
835{
836 hashcpy(cur_sha1, new_sha1);
837 return 0;
838}
839
840int combine_notes_ignore(unsigned char *cur_sha1,
841 const unsigned char *new_sha1)
842{
843 return 0;
844}
845
894a9d33
TR
846static int string_list_add_one_ref(const char *path, const unsigned char *sha1,
847 int flag, void *cb)
848{
849 struct string_list *refs = cb;
850 if (!unsorted_string_list_has_string(refs, path))
1d2f80fa 851 string_list_append(refs, path);
894a9d33
TR
852 return 0;
853}
854
855void string_list_add_refs_by_glob(struct string_list *list, const char *glob)
856{
857 if (has_glob_specials(glob)) {
858 for_each_glob_ref(string_list_add_one_ref, glob, list);
859 } else {
860 unsigned char sha1[20];
861 if (get_sha1(glob, sha1))
862 warning("notes ref %s is invalid", glob);
863 if (!unsorted_string_list_has_string(list, glob))
1d2f80fa 864 string_list_append(list, glob);
894a9d33
TR
865 }
866}
867
868void string_list_add_refs_from_colon_sep(struct string_list *list,
869 const char *globs)
870{
871 struct strbuf globbuf = STRBUF_INIT;
872 struct strbuf **split;
873 int i;
874
875 strbuf_addstr(&globbuf, globs);
876 split = strbuf_split(&globbuf, ':');
877
878 for (i = 0; split[i]; i++) {
879 if (!split[i]->len)
880 continue;
881 if (split[i]->buf[split[i]->len-1] == ':')
882 strbuf_setlen(split[i], split[i]->len-1);
883 string_list_add_refs_by_glob(list, split[i]->buf);
884 }
885
886 strbuf_list_free(split);
887 strbuf_release(&globbuf);
888}
889
890static int string_list_add_refs_from_list(struct string_list_item *item,
891 void *cb)
892{
893 struct string_list *list = cb;
894 string_list_add_refs_by_glob(list, item->string);
895 return 0;
896}
897
898static int notes_display_config(const char *k, const char *v, void *cb)
899{
900 int *load_refs = cb;
901
902 if (*load_refs && !strcmp(k, "notes.displayref")) {
903 if (!v)
904 config_error_nonbool(k);
905 string_list_add_refs_by_glob(&display_notes_refs, v);
906 }
907
908 return 0;
909}
910
4a9cf1ce 911const char *default_notes_ref(void)
894a9d33
TR
912{
913 const char *notes_ref = NULL;
914 if (!notes_ref)
915 notes_ref = getenv(GIT_NOTES_REF_ENVIRONMENT);
916 if (!notes_ref)
917 notes_ref = notes_ref_name; /* value of core.notesRef config */
918 if (!notes_ref)
919 notes_ref = GIT_NOTES_DEFAULT_REF;
920 return notes_ref;
921}
922
73f464b5
JH
923void init_notes(struct notes_tree *t, const char *notes_ref,
924 combine_notes_fn combine_notes, int flags)
23123aec 925{
a7e7eff6 926 unsigned char sha1[20], object_sha1[20];
23123aec
JH
927 unsigned mode;
928 struct leaf_node root_tree;
fd53c9eb 929
cd305392
JH
930 if (!t)
931 t = &default_notes_tree;
932 assert(!t->initialized);
709f79b0
JH
933
934 if (!notes_ref)
894a9d33 935 notes_ref = default_notes_ref();
709f79b0 936
73f464b5
JH
937 if (!combine_notes)
938 combine_notes = combine_notes_concatenate;
939
cd305392 940 t->root = (struct int_node *) xcalloc(sizeof(struct int_node), 1);
851c2b37
JH
941 t->first_non_note = NULL;
942 t->prev_non_note = NULL;
cd305392 943 t->ref = notes_ref ? xstrdup(notes_ref) : NULL;
73f464b5 944 t->combine_notes = combine_notes;
cd305392 945 t->initialized = 1;
7f710ea9 946 t->dirty = 0;
cd305392 947
709f79b0
JH
948 if (flags & NOTES_INIT_EMPTY || !notes_ref ||
949 read_ref(notes_ref, object_sha1))
fd53c9eb 950 return;
709f79b0
JH
951 if (get_tree_entry(object_sha1, "", sha1, &mode))
952 die("Failed to read notes tree referenced by %s (%s)",
327a89dc 953 notes_ref, sha1_to_hex(object_sha1));
fd53c9eb 954
23123aec
JH
955 hashclr(root_tree.key_sha1);
956 hashcpy(root_tree.val_sha1, sha1);
851c2b37 957 load_subtree(t, &root_tree, t->root, 0);
fd53c9eb
JS
958}
959
894a9d33
TR
960struct load_notes_cb_data {
961 int counter;
962 struct notes_tree **trees;
963};
964
965static int load_one_display_note_ref(struct string_list_item *item,
966 void *cb_data)
967{
968 struct load_notes_cb_data *c = cb_data;
969 struct notes_tree *t = xcalloc(1, sizeof(struct notes_tree));
970 init_notes(t, item->string, combine_notes_ignore, 0);
971 c->trees[c->counter++] = t;
972 return 0;
973}
974
975struct notes_tree **load_notes_trees(struct string_list *refs)
976{
977 struct notes_tree **trees;
978 struct load_notes_cb_data cb_data;
979 trees = xmalloc((refs->nr+1) * sizeof(struct notes_tree *));
980 cb_data.counter = 0;
981 cb_data.trees = trees;
b684e977 982 for_each_string_list(refs, load_one_display_note_ref, &cb_data);
894a9d33
TR
983 trees[cb_data.counter] = NULL;
984 return trees;
985}
986
987void init_display_notes(struct display_notes_opt *opt)
988{
989 char *display_ref_env;
990 int load_config_refs = 0;
991 display_notes_refs.strdup_strings = 1;
992
993 assert(!display_notes_trees);
994
995 if (!opt || !opt->suppress_default_notes) {
1d2f80fa 996 string_list_append(&display_notes_refs, default_notes_ref());
894a9d33
TR
997 display_ref_env = getenv(GIT_NOTES_DISPLAY_REF_ENVIRONMENT);
998 if (display_ref_env) {
999 string_list_add_refs_from_colon_sep(&display_notes_refs,
1000 display_ref_env);
1001 load_config_refs = 0;
1002 } else
1003 load_config_refs = 1;
1004 }
1005
1006 git_config(notes_display_config, &load_config_refs);
1007
1008 if (opt && opt->extra_notes_refs)
b684e977
JP
1009 for_each_string_list(opt->extra_notes_refs,
1010 string_list_add_refs_from_list,
894a9d33
TR
1011 &display_notes_refs);
1012
1013 display_notes_trees = load_notes_trees(&display_notes_refs);
1014 string_list_clear(&display_notes_refs, 0);
1015}
1016
cd305392 1017void add_note(struct notes_tree *t, const unsigned char *object_sha1,
73f464b5 1018 const unsigned char *note_sha1, combine_notes_fn combine_notes)
2626b536
JH
1019{
1020 struct leaf_node *l;
1021
cd305392
JH
1022 if (!t)
1023 t = &default_notes_tree;
1024 assert(t->initialized);
7f710ea9 1025 t->dirty = 1;
73f464b5
JH
1026 if (!combine_notes)
1027 combine_notes = t->combine_notes;
2626b536
JH
1028 l = (struct leaf_node *) xmalloc(sizeof(struct leaf_node));
1029 hashcpy(l->key_sha1, object_sha1);
1030 hashcpy(l->val_sha1, note_sha1);
851c2b37 1031 note_tree_insert(t, t->root, 0, l, PTR_TYPE_NOTE, combine_notes);
2626b536
JH
1032}
1033
cd305392 1034void remove_note(struct notes_tree *t, const unsigned char *object_sha1)
1ec666b0
JH
1035{
1036 struct leaf_node l;
1037
cd305392
JH
1038 if (!t)
1039 t = &default_notes_tree;
1040 assert(t->initialized);
7f710ea9 1041 t->dirty = 1;
1ec666b0
JH
1042 hashcpy(l.key_sha1, object_sha1);
1043 hashclr(l.val_sha1);
a502ab93 1044 note_tree_remove(t, t->root, 0, &l);
1ec666b0
JH
1045}
1046
cd305392
JH
1047const unsigned char *get_note(struct notes_tree *t,
1048 const unsigned char *object_sha1)
fd53c9eb 1049{
9b391f21
JH
1050 struct leaf_node *found;
1051
cd305392
JH
1052 if (!t)
1053 t = &default_notes_tree;
1054 assert(t->initialized);
851c2b37 1055 found = note_tree_find(t, t->root, 0, object_sha1);
9b391f21 1056 return found ? found->val_sha1 : NULL;
fd53c9eb 1057}
a97a7468 1058
cd305392
JH
1059int for_each_note(struct notes_tree *t, int flags, each_note_fn fn,
1060 void *cb_data)
73f77b90 1061{
cd305392
JH
1062 if (!t)
1063 t = &default_notes_tree;
1064 assert(t->initialized);
851c2b37 1065 return for_each_note_helper(t, t->root, 0, 0, flags, fn, cb_data);
73f77b90
JH
1066}
1067
cd305392 1068int write_notes_tree(struct notes_tree *t, unsigned char *result)
61a7cca0
JH
1069{
1070 struct tree_write_stack root;
1071 struct write_each_note_data cb_data;
1072 int ret;
1073
cd305392
JH
1074 if (!t)
1075 t = &default_notes_tree;
1076 assert(t->initialized);
61a7cca0
JH
1077
1078 /* Prepare for traversal of current notes tree */
1079 root.next = NULL; /* last forward entry in list is grounded */
1080 strbuf_init(&root.buf, 256 * (32 + 40)); /* assume 256 entries */
1081 root.path[0] = root.path[1] = '\0';
1082 cb_data.root = &root;
851c2b37 1083 cb_data.next_non_note = t->first_non_note;
61a7cca0
JH
1084
1085 /* Write tree objects representing current notes tree */
cd305392 1086 ret = for_each_note(t, FOR_EACH_NOTE_DONT_UNPACK_SUBTREES |
61a7cca0
JH
1087 FOR_EACH_NOTE_YIELD_SUBTREES,
1088 write_each_note, &cb_data) ||
851c2b37 1089 write_each_non_note_until(NULL, &cb_data) ||
61a7cca0
JH
1090 tree_write_stack_finish_subtree(&root) ||
1091 write_sha1_file(root.buf.buf, root.buf.len, tree_type, result);
1092 strbuf_release(&root.buf);
1093 return ret;
1094}
1095
a9f2adff 1096void prune_notes(struct notes_tree *t, int flags)
00fbe636
JH
1097{
1098 struct note_delete_list *l = NULL;
1099
1100 if (!t)
1101 t = &default_notes_tree;
1102 assert(t->initialized);
1103
1104 for_each_note(t, 0, prune_notes_helper, &l);
1105
1106 while (l) {
a9f2adff
MG
1107 if (flags & NOTES_PRUNE_VERBOSE)
1108 printf("%s\n", sha1_to_hex(l->sha1));
1109 if (!(flags & NOTES_PRUNE_DRYRUN))
1110 remove_note(t, l->sha1);
00fbe636
JH
1111 l = l->next;
1112 }
1113}
1114
cd305392 1115void free_notes(struct notes_tree *t)
27d57564 1116{
cd305392
JH
1117 if (!t)
1118 t = &default_notes_tree;
1119 if (t->root)
1120 note_tree_free(t->root);
1121 free(t->root);
851c2b37
JH
1122 while (t->first_non_note) {
1123 t->prev_non_note = t->first_non_note->next;
1124 free(t->first_non_note->path);
1125 free(t->first_non_note);
1126 t->first_non_note = t->prev_non_note;
1127 }
cd305392
JH
1128 free(t->ref);
1129 memset(t, 0, sizeof(struct notes_tree));
27d57564
JH
1130}
1131
cd305392
JH
1132void format_note(struct notes_tree *t, const unsigned char *object_sha1,
1133 struct strbuf *sb, const char *output_encoding, int flags)
a97a7468
JS
1134{
1135 static const char utf8[] = "utf-8";
9b391f21 1136 const unsigned char *sha1;
a97a7468
JS
1137 char *msg, *msg_p;
1138 unsigned long linelen, msglen;
1139 enum object_type type;
1140
cd305392
JH
1141 if (!t)
1142 t = &default_notes_tree;
1143 if (!t->initialized)
73f464b5 1144 init_notes(t, NULL, NULL, 0);
a97a7468 1145
cd305392 1146 sha1 = get_note(t, object_sha1);
fd53c9eb 1147 if (!sha1)
a97a7468
JS
1148 return;
1149
1150 if (!(msg = read_sha1_file(sha1, &type, &msglen)) || !msglen ||
1151 type != OBJ_BLOB) {
1152 free(msg);
1153 return;
1154 }
1155
1156 if (output_encoding && *output_encoding &&
1157 strcmp(utf8, output_encoding)) {
1158 char *reencoded = reencode_string(msg, output_encoding, utf8);
1159 if (reencoded) {
1160 free(msg);
1161 msg = reencoded;
1162 msglen = strlen(msg);
1163 }
1164 }
1165
1166 /* we will end the annotation by a newline anyway */
1167 if (msglen && msg[msglen - 1] == '\n')
1168 msglen--;
1169
894a9d33
TR
1170 if (flags & NOTES_SHOW_HEADER) {
1171 const char *ref = t->ref;
1172 if (!ref || !strcmp(ref, GIT_NOTES_DEFAULT_REF)) {
1173 strbuf_addstr(sb, "\nNotes:\n");
1174 } else {
1175 if (!prefixcmp(ref, "refs/"))
1176 ref += 5;
1177 if (!prefixcmp(ref, "notes/"))
1178 ref += 6;
1179 strbuf_addf(sb, "\nNotes (%s):\n", ref);
1180 }
1181 }
a97a7468
JS
1182
1183 for (msg_p = msg; msg_p < msg + msglen; msg_p += linelen + 1) {
1184 linelen = strchrnul(msg_p, '\n') - msg_p;
1185
c56fcc89
JH
1186 if (flags & NOTES_INDENT)
1187 strbuf_addstr(sb, " ");
a97a7468
JS
1188 strbuf_add(sb, msg_p, linelen);
1189 strbuf_addch(sb, '\n');
1190 }
1191
1192 free(msg);
1193}
894a9d33
TR
1194
1195void format_display_notes(const unsigned char *object_sha1,
1196 struct strbuf *sb, const char *output_encoding, int flags)
1197{
1198 int i;
1199 assert(display_notes_trees);
1200 for (i = 0; display_notes_trees[i]; i++)
1201 format_note(display_notes_trees[i], object_sha1, sb,
1202 output_encoding, flags);
1203}
160baa0d
TR
1204
1205int copy_note(struct notes_tree *t,
1206 const unsigned char *from_obj, const unsigned char *to_obj,
1207 int force, combine_notes_fn combine_fn)
1208{
1209 const unsigned char *note = get_note(t, from_obj);
1210 const unsigned char *existing_note = get_note(t, to_obj);
1211
1212 if (!force && existing_note)
1213 return 1;
1214
1215 if (note)
1216 add_note(t, to_obj, note, combine_fn);
1217 else if (existing_note)
1218 add_note(t, to_obj, null_sha1, combine_fn);
1219
1220 return 0;
1221}