[thirdparty/git.git] / notes.c

#include "cache.h"
#include "commit.h"
#include "notes.h"
#include "refs.h"
#include "utf8.h"
#include "strbuf.h"
#include "tree-walk.h"

/*
 * Use a non-balancing simple 16-tree structure with struct int_node as
 * internal nodes, and struct leaf_node as leaf nodes. Each int_node has a
 * 16-array of pointers to its children.
 * The bottom 2 bits of each pointer is used to identify the pointer type
 * - ptr & 3 == 0 - NULL pointer, assert(ptr == NULL)
 * - ptr & 3 == 1 - pointer to next internal node - cast to struct int_node *
 * - ptr & 3 == 2 - pointer to note entry - cast to struct leaf_node *
 * - ptr & 3 == 3 - pointer to subtree entry - cast to struct leaf_node *
 *
 * The root node is a statically allocated struct int_node.
 */
struct int_node {
	void *a[16];
};

/*
 * Leaf nodes come in two variants, note entries and subtree entries,
 * distinguished by the LSb of the leaf node pointer (see above).
 * As a note entry, the key is the SHA1 of the referenced commit, and the
 * value is the SHA1 of the note object.
 * As a subtree entry, the key is the prefix SHA1 (w/trailing NULs) of the
 * referenced commit, using the last byte of the key to store the length of
 * the prefix. The value is the SHA1 of the tree object containing the notes
 * subtree.
 */
struct leaf_node {
	unsigned char key_sha1[20];
	unsigned char val_sha1[20];
};

#define PTR_TYPE_NULL     0
#define PTR_TYPE_INTERNAL 1
#define PTR_TYPE_NOTE     2
#define PTR_TYPE_SUBTREE  3

#define GET_PTR_TYPE(ptr)       ((uintptr_t) (ptr) & 3)
#define CLR_PTR_TYPE(ptr)       ((void *) ((uintptr_t) (ptr) & ~3))
#define SET_PTR_TYPE(ptr, type) ((void *) ((uintptr_t) (ptr) | (type)))

#define GET_NIBBLE(n, sha1) (((sha1[n >> 1]) >> ((~n & 0x01) << 2)) & 0x0f)

#define SUBTREE_SHA1_PREFIXCMP(key_sha1, subtree_sha1) \
	(memcmp(key_sha1, subtree_sha1, subtree_sha1[19]))

static struct int_node root_node;

static int initialized;

static void load_subtree(struct leaf_node *subtree, struct int_node *node,
		unsigned int n);

/*
 * To find a leaf_node:
 * 1. Start at the root node, with n = 0
 * 2. Use the nth nibble of the key as an index into a:
 *    - If a[n] is an int_node, recurse into that node and increment n
 *    - If a leaf_node with matching key, return leaf_node (assert note entry)
 *    - If a matching subtree entry, unpack that subtree entry (and remove it);
 *      restart search at the current level.
 *    - Otherwise, we end up at a NULL pointer, or a non-matching leaf_node.
 *      Backtrack out of the recursion, one level at a time and check a[0]:
 *      - If a[0] at the current level is a matching subtree entry, unpack that
 *        subtree entry (and remove it); restart search at the current level.
 */
static struct leaf_node *note_tree_find(struct int_node *tree, unsigned char n,
		const unsigned char *key_sha1)
{
	struct leaf_node *l;
	unsigned char i = GET_NIBBLE(n, key_sha1);
	void *p = tree->a[i];

	switch(GET_PTR_TYPE(p)) {
	case PTR_TYPE_INTERNAL:
		l = note_tree_find(CLR_PTR_TYPE(p), n + 1, key_sha1);
		if (l)
			return l;
		break;
	case PTR_TYPE_NOTE:
		l = (struct leaf_node *) CLR_PTR_TYPE(p);
		if (!hashcmp(key_sha1, l->key_sha1))
			return l; /* return note object matching given key */
		break;
	case PTR_TYPE_SUBTREE:
		l = (struct leaf_node *) CLR_PTR_TYPE(p);
		if (!SUBTREE_SHA1_PREFIXCMP(key_sha1, l->key_sha1)) {
			/* unpack tree and resume search */
			tree->a[i] = NULL;
			load_subtree(l, tree, n);
			free(l);
			return note_tree_find(tree, n, key_sha1);
		}
		break;
	case PTR_TYPE_NULL:
	default:
		assert(!p);
		break;
	}

	/*
	 * Did not find key at this (or any lower) level.
	 * Check if there's a matching subtree entry in tree->a[0].
	 * If so, unpack tree and resume search.
	 */
	p = tree->a[0];
	if (GET_PTR_TYPE(p) != PTR_TYPE_SUBTREE)
		return NULL;
	l = (struct leaf_node *) CLR_PTR_TYPE(p);
	if (!SUBTREE_SHA1_PREFIXCMP(key_sha1, l->key_sha1)) {
		/* unpack tree and resume search */
		tree->a[0] = NULL;
		load_subtree(l, tree, n);
		free(l);
		return note_tree_find(tree, n, key_sha1);
	}
	return NULL;
}

/*
 * To insert a leaf_node:
 * 1. Start at the root node, with n = 0
 * 2. Use the nth nibble of the key as an index into a:
 *    - If a[n] is NULL, store the tweaked pointer directly into a[n]
 *    - If a[n] is an int_node, recurse into that node and increment n
 *    - If a[n] is a leaf_node:
 *      1. Check if they're equal, and handle that (abort? overwrite?)
 *      2. Create a new int_node, and store both leaf_nodes there
 *      3. Store the new int_node into a[n].
 */
static int note_tree_insert(struct int_node *tree, unsigned char n,
		const struct leaf_node *entry, unsigned char type)
{
	struct int_node *new_node;
	const struct leaf_node *l;
	int ret;
	unsigned char i = GET_NIBBLE(n, entry->key_sha1);
	void *p = tree->a[i];
	assert(GET_PTR_TYPE(entry) == PTR_TYPE_NULL);
	switch(GET_PTR_TYPE(p)) {
	case PTR_TYPE_NULL:
		assert(!p);
		tree->a[i] = SET_PTR_TYPE(entry, type);
		return 0;
	case PTR_TYPE_INTERNAL:
		return note_tree_insert(CLR_PTR_TYPE(p), n + 1, entry, type);
	default:
		assert(GET_PTR_TYPE(p) == PTR_TYPE_NOTE ||
			GET_PTR_TYPE(p) == PTR_TYPE_SUBTREE);
		l = (const struct leaf_node *) CLR_PTR_TYPE(p);
		if (!hashcmp(entry->key_sha1, l->key_sha1))
			return -1; /* abort insert on matching key */
		new_node = (struct int_node *)
			xcalloc(sizeof(struct int_node), 1);
		ret = note_tree_insert(new_node, n + 1,
			CLR_PTR_TYPE(p), GET_PTR_TYPE(p));
		if (ret) {
			free(new_node);
			return -1;
		}
		tree->a[i] = SET_PTR_TYPE(new_node, PTR_TYPE_INTERNAL);
		return note_tree_insert(new_node, n + 1, entry, type);
	}
}

/* Free the entire notes data contained in the given tree */
static void note_tree_free(struct int_node *tree)
{
	unsigned int i;
	for (i = 0; i < 16; i++) {
		void *p = tree->a[i];
		switch(GET_PTR_TYPE(p)) {
		case PTR_TYPE_INTERNAL:
			note_tree_free(CLR_PTR_TYPE(p));
			/* fall through */
		case PTR_TYPE_NOTE:
		case PTR_TYPE_SUBTREE:
			free(CLR_PTR_TYPE(p));
		}
	}
}

/*
 * Convert a partial SHA1 hex string to the corresponding partial SHA1 value.
 * - hex      - Partial SHA1 segment in ASCII hex format
 * - hex_len  - Length of above segment. Must be multiple of 2 between 0 and 40
 * - sha1     - Partial SHA1 value is written here
 * - sha1_len - Max #bytes to store in sha1, Must be >= hex_len / 2, and < 20
 * Returns -1 on error (invalid arguments or invalid SHA1 (not in hex format).
 * Otherwise, returns number of bytes written to sha1 (i.e. hex_len / 2).
 * Pads sha1 with NULs up to sha1_len (not included in returned length).
 */
static int get_sha1_hex_segment(const char *hex, unsigned int hex_len,
		unsigned char *sha1, unsigned int sha1_len)
{
	unsigned int i, len = hex_len >> 1;
	if (hex_len % 2 != 0 || len > sha1_len)
		return -1;
	for (i = 0; i < len; i++) {
		unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
		if (val & ~0xff)
			return -1;
		*sha1++ = val;
		hex += 2;
	}
	for (; i < sha1_len; i++)
		*sha1++ = 0;
	return len;
}

static void load_subtree(struct leaf_node *subtree, struct int_node *node,
		unsigned int n)
{
	unsigned char commit_sha1[20];
	unsigned int prefix_len;
	int status;
	void *buf;
	struct tree_desc desc;
	struct name_entry entry;

	buf = fill_tree_descriptor(&desc, subtree->val_sha1);
	if (!buf)
		die("Could not read %s for notes-index",
		     sha1_to_hex(subtree->val_sha1));

	prefix_len = subtree->key_sha1[19];
	assert(prefix_len * 2 >= n);
	memcpy(commit_sha1, subtree->key_sha1, prefix_len);
	while (tree_entry(&desc, &entry)) {
		int len = get_sha1_hex_segment(entry.path, strlen(entry.path),
				commit_sha1 + prefix_len, 20 - prefix_len);
		if (len < 0)
			continue; /* entry.path is not a SHA1 sum. Skip */
		len += prefix_len;

		/*
		 * If commit SHA1 is complete (len == 20), assume note object
		 * If commit SHA1 is incomplete (len < 20), assume note subtree
		 */
		if (len <= 20) {
			unsigned char type = PTR_TYPE_NOTE;
			struct leaf_node *l = (struct leaf_node *)
				xcalloc(sizeof(struct leaf_node), 1);
			hashcpy(l->key_sha1, commit_sha1);
			hashcpy(l->val_sha1, entry.sha1);
			if (len < 20) {
				l->key_sha1[19] = (unsigned char) len;
				type = PTR_TYPE_SUBTREE;
			}
			status = note_tree_insert(node, n, l, type);
			assert(!status);
		}
	}
	free(buf);
}

static void initialize_notes(const char *notes_ref_name)
{
	unsigned char sha1[20], commit_sha1[20];
	unsigned mode;
	struct leaf_node root_tree;

	if (!notes_ref_name || read_ref(notes_ref_name, commit_sha1) ||
	    get_tree_entry(commit_sha1, "", sha1, &mode))
		return;

	hashclr(root_tree.key_sha1);
	hashcpy(root_tree.val_sha1, sha1);
	load_subtree(&root_tree, &root_node, 0);
}

static unsigned char *lookup_notes(const unsigned char *commit_sha1)
{
	struct leaf_node *found = note_tree_find(&root_node, 0, commit_sha1);
	if (found)
		return found->val_sha1;
	return NULL;
}

void free_notes(void)
{
	note_tree_free(&root_node);
	memset(&root_node, 0, sizeof(struct int_node));
	initialized = 0;
}

void get_commit_notes(const struct commit *commit, struct strbuf *sb,
		const char *output_encoding, int flags)
{
	static const char utf8[] = "utf-8";
	unsigned char *sha1;
	char *msg, *msg_p;
	unsigned long linelen, msglen;
	enum object_type type;

	if (!initialized) {
		const char *env = getenv(GIT_NOTES_REF_ENVIRONMENT);
		if (env)
			notes_ref_name = getenv(GIT_NOTES_REF_ENVIRONMENT);
		else if (!notes_ref_name)
			notes_ref_name = GIT_NOTES_DEFAULT_REF;
		initialize_notes(notes_ref_name);
		initialized = 1;
	}

	sha1 = lookup_notes(commit->object.sha1);
	if (!sha1)
		return;

	if (!(msg = read_sha1_file(sha1, &type, &msglen)) || !msglen ||
			type != OBJ_BLOB) {
		free(msg);
		return;
	}

	if (output_encoding && *output_encoding &&
			strcmp(utf8, output_encoding)) {
		char *reencoded = reencode_string(msg, output_encoding, utf8);
		if (reencoded) {
			free(msg);
			msg = reencoded;
			msglen = strlen(msg);
		}
	}

	/* we will end the annotation by a newline anyway */
	if (msglen && msg[msglen - 1] == '\n')
		msglen--;

	if (flags & NOTES_SHOW_HEADER)
		strbuf_addstr(sb, "\nNotes:\n");

	for (msg_p = msg; msg_p < msg + msglen; msg_p += linelen + 1) {
		linelen = strchrnul(msg_p, '\n') - msg_p;

		if (flags & NOTES_INDENT)
			strbuf_addstr(sb, "    ");
		strbuf_add(sb, msg_p, linelen);
		strbuf_addch(sb, '\n');
	}

	free(msg);
}
Commit	Line	Data
a97a7468 JS	1	#include "cache.h"
	2	#include "commit.h"
	3	#include "notes.h"
	4	#include "refs.h"
	5	#include "utf8.h"
	6	#include "strbuf.h"
fd53c9eb JS	7	#include "tree-walk.h"
fd53c9eb JS	8
23123aec JH	9	/*
	10	* Use a non-balancing simple 16-tree structure with struct int_node as
	11	* internal nodes, and struct leaf_node as leaf nodes. Each int_node has a
	12	* 16-array of pointers to its children.
	13	* The bottom 2 bits of each pointer is used to identify the pointer type
	14	* - ptr & 3 == 0 - NULL pointer, assert(ptr == NULL)
	15	* - ptr & 3 == 1 - pointer to next internal node - cast to struct int_node *
	16	* - ptr & 3 == 2 - pointer to note entry - cast to struct leaf_node *
	17	* - ptr & 3 == 3 - pointer to subtree entry - cast to struct leaf_node *
	18	*
	19	* The root node is a statically allocated struct int_node.
	20	*/
	21	struct int_node {
	22	void *a[16];
fd53c9eb JS	23	};
fd53c9eb JS	24
23123aec JH	25	/*
	26	* Leaf nodes come in two variants, note entries and subtree entries,
	27	* distinguished by the LSb of the leaf node pointer (see above).
	28	* As a note entry, the key is the SHA1 of the referenced commit, and the
	29	* value is the SHA1 of the note object.
	30	* As a subtree entry, the key is the prefix SHA1 (w/trailing NULs) of the
	31	* referenced commit, using the last byte of the key to store the length of
	32	* the prefix. The value is the SHA1 of the tree object containing the notes
	33	* subtree.
	34	*/
	35	struct leaf_node {
	36	unsigned char key_sha1[20];
	37	unsigned char val_sha1[20];
fd53c9eb	38	};
a97a7468	39
23123aec JH	40	#define PTR_TYPE_NULL 0
	41	#define PTR_TYPE_INTERNAL 1
	42	#define PTR_TYPE_NOTE 2
	43	#define PTR_TYPE_SUBTREE 3
fd53c9eb	44
23123aec JH	45	#define GET_PTR_TYPE(ptr) ((uintptr_t) (ptr) & 3)
	46	#define CLR_PTR_TYPE(ptr) ((void *) ((uintptr_t) (ptr) & ~3))
	47	#define SET_PTR_TYPE(ptr, type) ((void *) ((uintptr_t) (ptr) \| (type)))
fd53c9eb	48
23123aec	49	#define GET_NIBBLE(n, sha1) (((sha1[n >> 1]) >> ((~n & 0x01) << 2)) & 0x0f)
fd53c9eb	50
23123aec JH	51	#define SUBTREE_SHA1_PREFIXCMP(key_sha1, subtree_sha1) \
23123aec JH	52	(memcmp(key_sha1, subtree_sha1, subtree_sha1[19]))
fd53c9eb	53
23123aec	54	static struct int_node root_node;
fd53c9eb	55
23123aec JH	56	static int initialized;
	57
	58	static void load_subtree(struct leaf_node subtree, struct int_node node,
	59	unsigned int n);
	60
	61	/*
	62	* To find a leaf_node:
	63	* 1. Start at the root node, with n = 0
	64	* 2. Use the nth nibble of the key as an index into a:
	65	* - If a[n] is an int_node, recurse into that node and increment n
	66	* - If a leaf_node with matching key, return leaf_node (assert note entry)
	67	* - If a matching subtree entry, unpack that subtree entry (and remove it);
	68	* restart search at the current level.
	69	* - Otherwise, we end up at a NULL pointer, or a non-matching leaf_node.
	70	* Backtrack out of the recursion, one level at a time and check a[0]:
	71	* - If a[0] at the current level is a matching subtree entry, unpack that
	72	* subtree entry (and remove it); restart search at the current level.
	73	*/
	74	static struct leaf_node note_tree_find(struct int_node tree, unsigned char n,
	75	const unsigned char *key_sha1)
	76	{
	77	struct leaf_node *l;
	78	unsigned char i = GET_NIBBLE(n, key_sha1);
	79	void *p = tree->a[i];
	80
	81	switch(GET_PTR_TYPE(p)) {
	82	case PTR_TYPE_INTERNAL:
	83	l = note_tree_find(CLR_PTR_TYPE(p), n + 1, key_sha1);
	84	if (l)
	85	return l;
	86	break;
	87	case PTR_TYPE_NOTE:
	88	l = (struct leaf_node *) CLR_PTR_TYPE(p);
	89	if (!hashcmp(key_sha1, l->key_sha1))
	90	return l; /* return note object matching given key */
	91	break;
	92	case PTR_TYPE_SUBTREE:
	93	l = (struct leaf_node *) CLR_PTR_TYPE(p);
	94	if (!SUBTREE_SHA1_PREFIXCMP(key_sha1, l->key_sha1)) {
	95	/* unpack tree and resume search */
	96	tree->a[i] = NULL;
	97	load_subtree(l, tree, n);
	98	free(l);
	99	return note_tree_find(tree, n, key_sha1);
	100	}
	101	break;
	102	case PTR_TYPE_NULL:
	103	default:
	104	assert(!p);
	105	break;
fd53c9eb	106	}
23123aec JH	107
	108	/*
	109	* Did not find key at this (or any lower) level.
	110	* Check if there's a matching subtree entry in tree->a[0].
	111	* If so, unpack tree and resume search.
	112	*/
	113	p = tree->a[0];
	114	if (GET_PTR_TYPE(p) != PTR_TYPE_SUBTREE)
	115	return NULL;
	116	l = (struct leaf_node *) CLR_PTR_TYPE(p);
	117	if (!SUBTREE_SHA1_PREFIXCMP(key_sha1, l->key_sha1)) {
	118	/* unpack tree and resume search */
	119	tree->a[0] = NULL;
	120	load_subtree(l, tree, n);
	121	free(l);
	122	return note_tree_find(tree, n, key_sha1);
	123	}
	124	return NULL;
fd53c9eb JS	125	}
fd53c9eb JS	126
23123aec JH	127	/*
	128	* To insert a leaf_node:
	129	* 1. Start at the root node, with n = 0
	130	* 2. Use the nth nibble of the key as an index into a:
	131	* - If a[n] is NULL, store the tweaked pointer directly into a[n]
	132	* - If a[n] is an int_node, recurse into that node and increment n
	133	* - If a[n] is a leaf_node:
	134	* 1. Check if they're equal, and handle that (abort? overwrite?)
	135	* 2. Create a new int_node, and store both leaf_nodes there
	136	* 3. Store the new int_node into a[n].
	137	*/
	138	static int note_tree_insert(struct int_node *tree, unsigned char n,
	139	const struct leaf_node *entry, unsigned char type)
fd53c9eb	140	{
23123aec JH	141	struct int_node *new_node;
	142	const struct leaf_node *l;
	143	int ret;
	144	unsigned char i = GET_NIBBLE(n, entry->key_sha1);
	145	void *p = tree->a[i];
	146	assert(GET_PTR_TYPE(entry) == PTR_TYPE_NULL);
	147	switch(GET_PTR_TYPE(p)) {
	148	case PTR_TYPE_NULL:
	149	assert(!p);
	150	tree->a[i] = SET_PTR_TYPE(entry, type);
	151	return 0;
	152	case PTR_TYPE_INTERNAL:
	153	return note_tree_insert(CLR_PTR_TYPE(p), n + 1, entry, type);
	154	default:
	155	assert(GET_PTR_TYPE(p) == PTR_TYPE_NOTE \|\|
	156	GET_PTR_TYPE(p) == PTR_TYPE_SUBTREE);
	157	l = (const struct leaf_node *) CLR_PTR_TYPE(p);
	158	if (!hashcmp(entry->key_sha1, l->key_sha1))
	159	return -1; /* abort insert on matching key */
	160	new_node = (struct int_node *)
	161	xcalloc(sizeof(struct int_node), 1);
	162	ret = note_tree_insert(new_node, n + 1,
	163	CLR_PTR_TYPE(p), GET_PTR_TYPE(p));
	164	if (ret) {
	165	free(new_node);
	166	return -1;
	167	}
	168	tree->a[i] = SET_PTR_TYPE(new_node, PTR_TYPE_INTERNAL);
	169	return note_tree_insert(new_node, n + 1, entry, type);
fd53c9eb	170	}
23123aec	171	}
fd53c9eb	172
23123aec JH	173	/* Free the entire notes data contained in the given tree */
	174	static void note_tree_free(struct int_node *tree)
	175	{
	176	unsigned int i;
	177	for (i = 0; i < 16; i++) {
	178	void *p = tree->a[i];
	179	switch(GET_PTR_TYPE(p)) {
	180	case PTR_TYPE_INTERNAL:
	181	note_tree_free(CLR_PTR_TYPE(p));
	182	/* fall through */
	183	case PTR_TYPE_NOTE:
	184	case PTR_TYPE_SUBTREE:
	185	free(CLR_PTR_TYPE(p));
	186	}
fd53c9eb	187	}
23123aec	188	}
fd53c9eb	189
23123aec JH	190	/*
	191	* Convert a partial SHA1 hex string to the corresponding partial SHA1 value.
	192	* - hex - Partial SHA1 segment in ASCII hex format
	193	* - hex_len - Length of above segment. Must be multiple of 2 between 0 and 40
	194	* - sha1 - Partial SHA1 value is written here
	195	* - sha1_len - Max #bytes to store in sha1, Must be >= hex_len / 2, and < 20
	196	* Returns -1 on error (invalid arguments or invalid SHA1 (not in hex format).
	197	* Otherwise, returns number of bytes written to sha1 (i.e. hex_len / 2).
	198	* Pads sha1 with NULs up to sha1_len (not included in returned length).
	199	*/
	200	static int get_sha1_hex_segment(const char *hex, unsigned int hex_len,
	201	unsigned char *sha1, unsigned int sha1_len)
	202	{
	203	unsigned int i, len = hex_len >> 1;
	204	if (hex_len % 2 != 0 \|\| len > sha1_len)
	205	return -1;
	206	for (i = 0; i < len; i++) {
	207	unsigned int val = (hexval(hex[0]) << 4) \| hexval(hex[1]);
	208	if (val & ~0xff)
	209	return -1;
	210	*sha1++ = val;
	211	hex += 2;
	212	}
	213	for (; i < sha1_len; i++)
	214	*sha1++ = 0;
	215	return len;
fd53c9eb JS	216	}
fd53c9eb JS	217
23123aec JH	218	static void load_subtree(struct leaf_node subtree, struct int_node node,
23123aec JH	219	unsigned int n)
fd53c9eb	220	{
23123aec JH	221	unsigned char commit_sha1[20];
	222	unsigned int prefix_len;
	223	int status;
	224	void *buf;
fd53c9eb JS	225	struct tree_desc desc;
fd53c9eb JS	226	struct name_entry entry;
23123aec JH	227
	228	buf = fill_tree_descriptor(&desc, subtree->val_sha1);
	229	if (!buf)
	230	die("Could not read %s for notes-index",
	231	sha1_to_hex(subtree->val_sha1));
	232
	233	prefix_len = subtree->key_sha1[19];
	234	assert(prefix_len * 2 >= n);
	235	memcpy(commit_sha1, subtree->key_sha1, prefix_len);
	236	while (tree_entry(&desc, &entry)) {
	237	int len = get_sha1_hex_segment(entry.path, strlen(entry.path),
	238	commit_sha1 + prefix_len, 20 - prefix_len);
	239	if (len < 0)
	240	continue; /* entry.path is not a SHA1 sum. Skip */
	241	len += prefix_len;
	242
	243	/*
	244	* If commit SHA1 is complete (len == 20), assume note object
	245	* If commit SHA1 is incomplete (len < 20), assume note subtree
	246	*/
	247	if (len <= 20) {
	248	unsigned char type = PTR_TYPE_NOTE;
	249	struct leaf_node l = (struct leaf_node )
	250	xcalloc(sizeof(struct leaf_node), 1);
	251	hashcpy(l->key_sha1, commit_sha1);
	252	hashcpy(l->val_sha1, entry.sha1);
	253	if (len < 20) {
	254	l->key_sha1[19] = (unsigned char) len;
	255	type = PTR_TYPE_SUBTREE;
	256	}
	257	status = note_tree_insert(node, n, l, type);
	258	assert(!status);
	259	}
	260	}
	261	free(buf);
	262	}
	263
	264	static void initialize_notes(const char *notes_ref_name)
	265	{
	266	unsigned char sha1[20], commit_sha1[20];
	267	unsigned mode;
	268	struct leaf_node root_tree;
fd53c9eb JS	269
	270	if (!notes_ref_name \|\| read_ref(notes_ref_name, commit_sha1) \|\|
	271	get_tree_entry(commit_sha1, "", sha1, &mode))
	272	return;
	273
23123aec JH	274	hashclr(root_tree.key_sha1);
	275	hashcpy(root_tree.val_sha1, sha1);
	276	load_subtree(&root_tree, &root_node, 0);
fd53c9eb JS	277	}
	278
	279	static unsigned char lookup_notes(const unsigned char commit_sha1)
	280	{
23123aec JH	281	struct leaf_node *found = note_tree_find(&root_node, 0, commit_sha1);
	282	if (found)
	283	return found->val_sha1;
	284	return NULL;
fd53c9eb	285	}
a97a7468	286
27d57564 JH	287	void free_notes(void)
27d57564 JH	288	{
23123aec JH	289	note_tree_free(&root_node);
23123aec JH	290	memset(&root_node, 0, sizeof(struct int_node));
27d57564 JH	291	initialized = 0;
	292	}
	293
a97a7468	294	void get_commit_notes(const struct commit commit, struct strbuf sb,
c56fcc89	295	const char *output_encoding, int flags)
a97a7468 JS	296	{
a97a7468 JS	297	static const char utf8[] = "utf-8";
fd53c9eb	298	unsigned char *sha1;
a97a7468 JS	299	char msg, msg_p;
	300	unsigned long linelen, msglen;
	301	enum object_type type;
	302
	303	if (!initialized) {
	304	const char *env = getenv(GIT_NOTES_REF_ENVIRONMENT);
	305	if (env)
	306	notes_ref_name = getenv(GIT_NOTES_REF_ENVIRONMENT);
	307	else if (!notes_ref_name)
	308	notes_ref_name = GIT_NOTES_DEFAULT_REF;
23123aec	309	initialize_notes(notes_ref_name);
a97a7468 JS	310	initialized = 1;
	311	}
	312
fd53c9eb JS	313	sha1 = lookup_notes(commit->object.sha1);
fd53c9eb JS	314	if (!sha1)
a97a7468 JS	315	return;
	316
	317	if (!(msg = read_sha1_file(sha1, &type, &msglen)) \|\| !msglen \|\|
	318	type != OBJ_BLOB) {
	319	free(msg);
	320	return;
	321	}
	322
	323	if (output_encoding && *output_encoding &&
	324	strcmp(utf8, output_encoding)) {
	325	char *reencoded = reencode_string(msg, output_encoding, utf8);
	326	if (reencoded) {
	327	free(msg);
	328	msg = reencoded;
	329	msglen = strlen(msg);
	330	}
	331	}
	332
	333	/* we will end the annotation by a newline anyway */
	334	if (msglen && msg[msglen - 1] == '\n')
	335	msglen--;
	336
c56fcc89 JH	337	if (flags & NOTES_SHOW_HEADER)
c56fcc89 JH	338	strbuf_addstr(sb, "\nNotes:\n");
a97a7468 JS	339
	340	for (msg_p = msg; msg_p < msg + msglen; msg_p += linelen + 1) {
	341	linelen = strchrnul(msg_p, '\n') - msg_p;
	342
c56fcc89 JH	343	if (flags & NOTES_INDENT)
c56fcc89 JH	344	strbuf_addstr(sb, " ");
a97a7468 JS	345	strbuf_add(sb, msg_p, linelen);
	346	strbuf_addch(sb, '\n');
	347	}
	348
	349	free(msg);
	350	}