[thirdparty/git.git] / notes.c

#include "cache.h"
#include "notes.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 object, 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 object, 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);

/*
 * Search the tree until the appropriate location for the given key is found:
 * 1. Start at the root node, with n = 0
 * 2. 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.
 * 3. Use the nth nibble of the key as an index into a:
 *    - If a[n] is an int_node, recurse from #2 into that node and increment n
 *    - If a matching subtree entry, unpack that subtree entry (and remove it);
 *      restart search at the current level.
 *    - Otherwise, we have found one of the following:
 *      - a subtree entry which does not match the key
 *      - a note entry which may or may not match the key
 *      - an unused leaf node (NULL)
 *      In any case, set *tree and *n, and return pointer to the tree location.
 */
static void **note_tree_search(struct int_node **tree,
		unsigned char *n, const unsigned char *key_sha1)
{
	struct leaf_node *l;
	unsigned char i;
	void *p = (*tree)->a[0];

	if (GET_PTR_TYPE(p) == 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[0] = NULL;
			load_subtree(l, *tree, *n);
			free(l);
			return note_tree_search(tree, n, key_sha1);
		}
	}

	i = GET_NIBBLE(*n, key_sha1);
	p = (*tree)->a[i];
	switch (GET_PTR_TYPE(p)) {
	case PTR_TYPE_INTERNAL:
		*tree = CLR_PTR_TYPE(p);
		(*n)++;
		return note_tree_search(tree, n, key_sha1);
	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_search(tree, n, key_sha1);
		}
		/* fall through */
	default:
		return &((*tree)->a[i]);
	}
}

/*
 * To find a leaf_node:
 * Search to the tree location appropriate for the given key:
 * If a note entry with matching key, return the note entry, else return NULL.
 */
static struct leaf_node *note_tree_find(struct int_node *tree, unsigned char n,
		const unsigned char *key_sha1)
{
	void **p = note_tree_search(&tree, &n, key_sha1);
	if (GET_PTR_TYPE(*p) == PTR_TYPE_NOTE) {
		struct leaf_node *l = (struct leaf_node *) CLR_PTR_TYPE(*p);
		if (!hashcmp(key_sha1, l->key_sha1))
			return l;
	}
	return NULL;
}

/* Create a new blob object by concatenating the two given blob objects */
static int concatenate_notes(unsigned char *cur_sha1,
		const unsigned char *new_sha1)
{
	char *cur_msg, *new_msg, *buf;
	unsigned long cur_len, new_len, buf_len;
	enum object_type cur_type, new_type;
	int ret;

	/* read in both note blob objects */
	new_msg = read_sha1_file(new_sha1, &new_type, &new_len);
	if (!new_msg || !new_len || new_type != OBJ_BLOB) {
		free(new_msg);
		return 0;
	}
	cur_msg = read_sha1_file(cur_sha1, &cur_type, &cur_len);
	if (!cur_msg || !cur_len || cur_type != OBJ_BLOB) {
		free(cur_msg);
		free(new_msg);
		hashcpy(cur_sha1, new_sha1);
		return 0;
	}

	/* we will separate the notes by a newline anyway */
	if (cur_msg[cur_len - 1] == '\n')
		cur_len--;

	/* concatenate cur_msg and new_msg into buf */
	buf_len = cur_len + 1 + new_len;
	buf = (char *) xmalloc(buf_len);
	memcpy(buf, cur_msg, cur_len);
	buf[cur_len] = '\n';
	memcpy(buf + cur_len + 1, new_msg, new_len);

	free(cur_msg);
	free(new_msg);

	/* create a new blob object from buf */
	ret = write_sha1_file(buf, buf_len, "blob", cur_sha1);
	free(buf);
	return ret;
}

/*
 * To insert a leaf_node:
 * Search to the tree location appropriate for the given leaf_node's key:
 * - If location is unused (NULL), store the tweaked pointer directly there
 * - If location holds a note entry that matches the note-to-be-inserted, then
 *   concatenate the two notes.
 * - If location holds a note entry that matches the subtree-to-be-inserted,
 *   then unpack the subtree-to-be-inserted into the location.
 * - If location holds a matching subtree entry, unpack the subtree at that
 *   location, and restart the insert operation from that level.
 * - Else, create a new int_node, holding both the node-at-location and the
 *   node-to-be-inserted, and store the new int_node into the location.
 */
static void note_tree_insert(struct int_node *tree, unsigned char n,
		struct leaf_node *entry, unsigned char type)
{
	struct int_node *new_node;
	struct leaf_node *l;
	void **p = note_tree_search(&tree, &n, entry->key_sha1);

	assert(GET_PTR_TYPE(entry) == 0); /* no type bits set */
	l = (struct leaf_node *) CLR_PTR_TYPE(*p);
	switch (GET_PTR_TYPE(*p)) {
	case PTR_TYPE_NULL:
		assert(!*p);
		*p = SET_PTR_TYPE(entry, type);
		return;
	case PTR_TYPE_NOTE:
		switch (type) {
		case PTR_TYPE_NOTE:
			if (!hashcmp(l->key_sha1, entry->key_sha1)) {
				/* skip concatenation if l == entry */
				if (!hashcmp(l->val_sha1, entry->val_sha1))
					return;

				if (concatenate_notes(l->val_sha1,
						entry->val_sha1))
					die("failed to concatenate note %s "
					    "into note %s for object %s",
					    sha1_to_hex(entry->val_sha1),
					    sha1_to_hex(l->val_sha1),
					    sha1_to_hex(l->key_sha1));
				free(entry);
				return;
			}
			break;
		case PTR_TYPE_SUBTREE:
			if (!SUBTREE_SHA1_PREFIXCMP(l->key_sha1,
						    entry->key_sha1)) {
				/* unpack 'entry' */
				load_subtree(entry, tree, n);
				free(entry);
				return;
			}
			break;
		}
		break;
	case PTR_TYPE_SUBTREE:
		if (!SUBTREE_SHA1_PREFIXCMP(entry->key_sha1, l->key_sha1)) {
			/* unpack 'l' and restart insert */
			*p = NULL;
			load_subtree(l, tree, n);
			free(l);
			note_tree_insert(tree, n, entry, type);
			return;
		}
		break;
	}

	/* non-matching leaf_node */
	assert(GET_PTR_TYPE(*p) == PTR_TYPE_NOTE ||
	       GET_PTR_TYPE(*p) == PTR_TYPE_SUBTREE);
	new_node = (struct int_node *) xcalloc(sizeof(struct int_node), 1);
	note_tree_insert(new_node, n + 1, l, GET_PTR_TYPE(*p));
	*p = SET_PTR_TYPE(new_node, PTR_TYPE_INTERNAL);
	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 object_sha1[20];
	unsigned int prefix_len;
	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(object_sha1, subtree->key_sha1, prefix_len);
	while (tree_entry(&desc, &entry)) {
		int len = get_sha1_hex_segment(entry.path, strlen(entry.path),
				object_sha1 + prefix_len, 20 - prefix_len);
		if (len < 0)
			continue; /* entry.path is not a SHA1 sum. Skip */
		len += prefix_len;

		/*
		 * If object SHA1 is complete (len == 20), assume note object
		 * If object 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, object_sha1);
			hashcpy(l->val_sha1, entry.sha1);
			if (len < 20) {
				if (!S_ISDIR(entry.mode))
					continue; /* entry cannot be subtree */
				l->key_sha1[19] = (unsigned char) len;
				type = PTR_TYPE_SUBTREE;
			}
			note_tree_insert(node, n, l, type);
		}
	}
	free(buf);
}

void init_notes(const char *notes_ref, int flags)
{
	unsigned char sha1[20], object_sha1[20];
	unsigned mode;
	struct leaf_node root_tree;

	assert(!initialized);
	initialized = 1;

	if (!notes_ref)
		notes_ref = getenv(GIT_NOTES_REF_ENVIRONMENT);
	if (!notes_ref)
		notes_ref = notes_ref_name; /* value of core.notesRef config */
	if (!notes_ref)
		notes_ref = GIT_NOTES_DEFAULT_REF;

	if (flags & NOTES_INIT_EMPTY || !notes_ref ||
	    read_ref(notes_ref, object_sha1))
		return;
	if (get_tree_entry(object_sha1, "", sha1, &mode))
		die("Failed to read notes tree referenced by %s (%s)",
		    notes_ref, object_sha1);

	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 *object_sha1)
{
	struct leaf_node *found = note_tree_find(&root_node, 0, object_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 format_note(const unsigned char *object_sha1, 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)
		init_notes(NULL, 0);

	sha1 = lookup_notes(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	1	#include "cache.h"
a97a7468	2	#include "notes.h"
a97a7468 JS	3	#include "utf8.h"
a97a7468 JS	4	#include "strbuf.h"
fd53c9eb JS	5	#include "tree-walk.h"
fd53c9eb JS	6
23123aec JH	7	/*
	8	* Use a non-balancing simple 16-tree structure with struct int_node as
	9	* internal nodes, and struct leaf_node as leaf nodes. Each int_node has a
	10	* 16-array of pointers to its children.
	11	* The bottom 2 bits of each pointer is used to identify the pointer type
	12	* - ptr & 3 == 0 - NULL pointer, assert(ptr == NULL)
	13	* - ptr & 3 == 1 - pointer to next internal node - cast to struct int_node *
	14	* - ptr & 3 == 2 - pointer to note entry - cast to struct leaf_node *
	15	* - ptr & 3 == 3 - pointer to subtree entry - cast to struct leaf_node *
	16	*
	17	* The root node is a statically allocated struct int_node.
	18	*/
	19	struct int_node {
	20	void *a[16];
fd53c9eb JS	21	};
fd53c9eb JS	22
23123aec JH	23	/*
	24	* Leaf nodes come in two variants, note entries and subtree entries,
	25	* distinguished by the LSb of the leaf node pointer (see above).
a7e7eff6	26	* As a note entry, the key is the SHA1 of the referenced object, and the
23123aec JH	27	* value is the SHA1 of the note object.
23123aec JH	28	* As a subtree entry, the key is the prefix SHA1 (w/trailing NULs) of the
a7e7eff6	29	* referenced object, using the last byte of the key to store the length of
23123aec JH	30	* the prefix. The value is the SHA1 of the tree object containing the notes
	31	* subtree.
	32	*/
	33	struct leaf_node {
	34	unsigned char key_sha1[20];
	35	unsigned char val_sha1[20];
fd53c9eb	36	};
a97a7468	37
23123aec JH	38	#define PTR_TYPE_NULL 0
	39	#define PTR_TYPE_INTERNAL 1
	40	#define PTR_TYPE_NOTE 2
	41	#define PTR_TYPE_SUBTREE 3
fd53c9eb	42
23123aec JH	43	#define GET_PTR_TYPE(ptr) ((uintptr_t) (ptr) & 3)
	44	#define CLR_PTR_TYPE(ptr) ((void *) ((uintptr_t) (ptr) & ~3))
	45	#define SET_PTR_TYPE(ptr, type) ((void *) ((uintptr_t) (ptr) \| (type)))
fd53c9eb	46
23123aec	47	#define GET_NIBBLE(n, sha1) (((sha1[n >> 1]) >> ((~n & 0x01) << 2)) & 0x0f)
fd53c9eb	48
23123aec JH	49	#define SUBTREE_SHA1_PREFIXCMP(key_sha1, subtree_sha1) \
23123aec JH	50	(memcmp(key_sha1, subtree_sha1, subtree_sha1[19]))
fd53c9eb	51
23123aec	52	static struct int_node root_node;
fd53c9eb	53
23123aec JH	54	static int initialized;
	55
	56	static void load_subtree(struct leaf_node subtree, struct int_node node,
	57	unsigned int n);
	58
	59	/*
ef8db638	60	* Search the tree until the appropriate location for the given key is found:
23123aec	61	* 1. Start at the root node, with n = 0
ef8db638 JH	62	* 2. If a[0] at the current level is a matching subtree entry, unpack that
	63	* subtree entry and remove it; restart search at the current level.
	64	* 3. Use the nth nibble of the key as an index into a:
	65	* - If a[n] is an int_node, recurse from #2 into that node and increment n
23123aec JH	66	* - If a matching subtree entry, unpack that subtree entry (and remove it);
23123aec JH	67	* restart search at the current level.
ef8db638 JH	68	* - Otherwise, we have found one of the following:
	69	* - a subtree entry which does not match the key
	70	* - a note entry which may or may not match the key
	71	* - an unused leaf node (NULL)
	72	* In any case, set tree and n, and return pointer to the tree location.
23123aec	73	*/
ef8db638 JH	74	static void note_tree_search(struct int_node tree,
ef8db638 JH	75	unsigned char n, const unsigned char key_sha1)
23123aec JH	76	{
23123aec JH	77	struct leaf_node *l;
ef8db638 JH	78	unsigned char i;
ef8db638 JH	79	void p = (tree)->a[0];
23123aec	80
ef8db638 JH	81	if (GET_PTR_TYPE(p) == PTR_TYPE_SUBTREE) {
	82	l = (struct leaf_node *) CLR_PTR_TYPE(p);
	83	if (!SUBTREE_SHA1_PREFIXCMP(key_sha1, l->key_sha1)) {
	84	/* unpack tree and resume search */
	85	(*tree)->a[0] = NULL;
	86	load_subtree(l, tree, n);
	87	free(l);
	88	return note_tree_search(tree, n, key_sha1);
	89	}
	90	}
	91
	92	i = GET_NIBBLE(*n, key_sha1);
	93	p = (*tree)->a[i];
0ab1faae	94	switch (GET_PTR_TYPE(p)) {
23123aec	95	case PTR_TYPE_INTERNAL:
ef8db638 JH	96	*tree = CLR_PTR_TYPE(p);
	97	(*n)++;
	98	return note_tree_search(tree, n, key_sha1);
23123aec JH	99	case PTR_TYPE_SUBTREE:
	100	l = (struct leaf_node *) CLR_PTR_TYPE(p);
	101	if (!SUBTREE_SHA1_PREFIXCMP(key_sha1, l->key_sha1)) {
	102	/* unpack tree and resume search */
ef8db638 JH	103	(*tree)->a[i] = NULL;
ef8db638 JH	104	load_subtree(l, tree, n);
23123aec	105	free(l);
ef8db638	106	return note_tree_search(tree, n, key_sha1);
23123aec	107	}
ef8db638	108	/* fall through */
23123aec	109	default:
ef8db638	110	return &((*tree)->a[i]);
fd53c9eb	111	}
ef8db638	112	}
23123aec	113
ef8db638 JH	114	/*
	115	* To find a leaf_node:
	116	* Search to the tree location appropriate for the given key:
	117	* If a note entry with matching key, return the note entry, else return NULL.
	118	*/
	119	static struct leaf_node note_tree_find(struct int_node tree, unsigned char n,
	120	const unsigned char *key_sha1)
	121	{
	122	void **p = note_tree_search(&tree, &n, key_sha1);
	123	if (GET_PTR_TYPE(*p) == PTR_TYPE_NOTE) {
	124	struct leaf_node l = (struct leaf_node ) CLR_PTR_TYPE(*p);
	125	if (!hashcmp(key_sha1, l->key_sha1))
	126	return l;
23123aec JH	127	}
23123aec JH	128	return NULL;
fd53c9eb JS	129	}
fd53c9eb JS	130
ef8db638 JH	131	/* Create a new blob object by concatenating the two given blob objects */
	132	static int concatenate_notes(unsigned char *cur_sha1,
	133	const unsigned char *new_sha1)
	134	{
	135	char cur_msg, new_msg, *buf;
	136	unsigned long cur_len, new_len, buf_len;
	137	enum object_type cur_type, new_type;
	138	int ret;
	139
	140	/* read in both note blob objects */
	141	new_msg = read_sha1_file(new_sha1, &new_type, &new_len);
	142	if (!new_msg \|\| !new_len \|\| new_type != OBJ_BLOB) {
	143	free(new_msg);
	144	return 0;
	145	}
	146	cur_msg = read_sha1_file(cur_sha1, &cur_type, &cur_len);
	147	if (!cur_msg \|\| !cur_len \|\| cur_type != OBJ_BLOB) {
	148	free(cur_msg);
	149	free(new_msg);
	150	hashcpy(cur_sha1, new_sha1);
	151	return 0;
	152	}
	153
	154	/* we will separate the notes by a newline anyway */
	155	if (cur_msg[cur_len - 1] == '\n')
	156	cur_len--;
	157
	158	/* concatenate cur_msg and new_msg into buf */
	159	buf_len = cur_len + 1 + new_len;
	160	buf = (char *) xmalloc(buf_len);
	161	memcpy(buf, cur_msg, cur_len);
	162	buf[cur_len] = '\n';
	163	memcpy(buf + cur_len + 1, new_msg, new_len);
	164
	165	free(cur_msg);
	166	free(new_msg);
	167
	168	/* create a new blob object from buf */
	169	ret = write_sha1_file(buf, buf_len, "blob", cur_sha1);
	170	free(buf);
	171	return ret;
	172	}
	173
23123aec JH	174	/*
23123aec JH	175	* To insert a leaf_node:
ef8db638 JH	176	* Search to the tree location appropriate for the given leaf_node's key:
	177	* - If location is unused (NULL), store the tweaked pointer directly there
	178	* - If location holds a note entry that matches the note-to-be-inserted, then
	179	* concatenate the two notes.
	180	* - If location holds a note entry that matches the subtree-to-be-inserted,
	181	* then unpack the subtree-to-be-inserted into the location.
	182	* - If location holds a matching subtree entry, unpack the subtree at that
	183	* location, and restart the insert operation from that level.
	184	* - Else, create a new int_node, holding both the node-at-location and the
	185	* node-to-be-inserted, and store the new int_node into the location.
23123aec	186	*/
ef8db638 JH	187	static void note_tree_insert(struct int_node *tree, unsigned char n,
ef8db638 JH	188	struct leaf_node *entry, unsigned char type)
fd53c9eb	189	{
23123aec	190	struct int_node *new_node;
ef8db638 JH	191	struct leaf_node *l;
	192	void **p = note_tree_search(&tree, &n, entry->key_sha1);
	193
	194	assert(GET_PTR_TYPE(entry) == 0); /* no type bits set */
	195	l = (struct leaf_node ) CLR_PTR_TYPE(p);
0ab1faae	196	switch (GET_PTR_TYPE(*p)) {
23123aec	197	case PTR_TYPE_NULL:
ef8db638 JH	198	assert(!*p);
	199	*p = SET_PTR_TYPE(entry, type);
	200	return;
	201	case PTR_TYPE_NOTE:
	202	switch (type) {
	203	case PTR_TYPE_NOTE:
	204	if (!hashcmp(l->key_sha1, entry->key_sha1)) {
	205	/* skip concatenation if l == entry */
	206	if (!hashcmp(l->val_sha1, entry->val_sha1))
	207	return;
	208
	209	if (concatenate_notes(l->val_sha1,
	210	entry->val_sha1))
	211	die("failed to concatenate note %s "
a7e7eff6	212	"into note %s for object %s",
ef8db638 JH	213	sha1_to_hex(entry->val_sha1),
	214	sha1_to_hex(l->val_sha1),
	215	sha1_to_hex(l->key_sha1));
	216	free(entry);
	217	return;
	218	}
	219	break;
	220	case PTR_TYPE_SUBTREE:
	221	if (!SUBTREE_SHA1_PREFIXCMP(l->key_sha1,
	222	entry->key_sha1)) {
	223	/* unpack 'entry' */
	224	load_subtree(entry, tree, n);
	225	free(entry);
	226	return;
	227	}
	228	break;
	229	}
	230	break;
	231	case PTR_TYPE_SUBTREE:
	232	if (!SUBTREE_SHA1_PREFIXCMP(entry->key_sha1, l->key_sha1)) {
	233	/* unpack 'l' and restart insert */
	234	*p = NULL;
	235	load_subtree(l, tree, n);
	236	free(l);
	237	note_tree_insert(tree, n, entry, type);
	238	return;
23123aec	239	}
ef8db638	240	break;
fd53c9eb	241	}
ef8db638 JH	242
	243	/* non-matching leaf_node */
	244	assert(GET_PTR_TYPE(*p) == PTR_TYPE_NOTE \|\|
	245	GET_PTR_TYPE(*p) == PTR_TYPE_SUBTREE);
	246	new_node = (struct int_node *) xcalloc(sizeof(struct int_node), 1);
	247	note_tree_insert(new_node, n + 1, l, GET_PTR_TYPE(*p));
	248	*p = SET_PTR_TYPE(new_node, PTR_TYPE_INTERNAL);
	249	note_tree_insert(new_node, n + 1, entry, type);
23123aec	250	}
fd53c9eb	251
23123aec JH	252	/* Free the entire notes data contained in the given tree */
	253	static void note_tree_free(struct int_node *tree)
	254	{
	255	unsigned int i;
	256	for (i = 0; i < 16; i++) {
	257	void *p = tree->a[i];
0ab1faae	258	switch (GET_PTR_TYPE(p)) {
23123aec JH	259	case PTR_TYPE_INTERNAL:
	260	note_tree_free(CLR_PTR_TYPE(p));
	261	/* fall through */
	262	case PTR_TYPE_NOTE:
	263	case PTR_TYPE_SUBTREE:
	264	free(CLR_PTR_TYPE(p));
	265	}
fd53c9eb	266	}
23123aec	267	}
fd53c9eb	268
23123aec JH	269	/*
	270	* Convert a partial SHA1 hex string to the corresponding partial SHA1 value.
	271	* - hex - Partial SHA1 segment in ASCII hex format
	272	* - hex_len - Length of above segment. Must be multiple of 2 between 0 and 40
	273	* - sha1 - Partial SHA1 value is written here
	274	* - sha1_len - Max #bytes to store in sha1, Must be >= hex_len / 2, and < 20
0ab1faae	275	* Returns -1 on error (invalid arguments or invalid SHA1 (not in hex format)).
23123aec JH	276	* Otherwise, returns number of bytes written to sha1 (i.e. hex_len / 2).
	277	* Pads sha1 with NULs up to sha1_len (not included in returned length).
	278	*/
	279	static int get_sha1_hex_segment(const char *hex, unsigned int hex_len,
	280	unsigned char *sha1, unsigned int sha1_len)
	281	{
	282	unsigned int i, len = hex_len >> 1;
	283	if (hex_len % 2 != 0 \|\| len > sha1_len)
	284	return -1;
	285	for (i = 0; i < len; i++) {
	286	unsigned int val = (hexval(hex[0]) << 4) \| hexval(hex[1]);
	287	if (val & ~0xff)
	288	return -1;
	289	*sha1++ = val;
	290	hex += 2;
	291	}
	292	for (; i < sha1_len; i++)
	293	*sha1++ = 0;
	294	return len;
fd53c9eb JS	295	}
fd53c9eb JS	296
23123aec JH	297	static void load_subtree(struct leaf_node subtree, struct int_node node,
23123aec JH	298	unsigned int n)
fd53c9eb	299	{
a7e7eff6	300	unsigned char object_sha1[20];
23123aec	301	unsigned int prefix_len;
23123aec	302	void *buf;
fd53c9eb JS	303	struct tree_desc desc;
fd53c9eb JS	304	struct name_entry entry;
23123aec JH	305
	306	buf = fill_tree_descriptor(&desc, subtree->val_sha1);
	307	if (!buf)
	308	die("Could not read %s for notes-index",
	309	sha1_to_hex(subtree->val_sha1));
	310
	311	prefix_len = subtree->key_sha1[19];
	312	assert(prefix_len * 2 >= n);
a7e7eff6	313	memcpy(object_sha1, subtree->key_sha1, prefix_len);
23123aec JH	314	while (tree_entry(&desc, &entry)) {
23123aec JH	315	int len = get_sha1_hex_segment(entry.path, strlen(entry.path),
a7e7eff6	316	object_sha1 + prefix_len, 20 - prefix_len);
23123aec JH	317	if (len < 0)
	318	continue; /* entry.path is not a SHA1 sum. Skip */
	319	len += prefix_len;
	320
	321	/*
a7e7eff6 JH	322	* If object SHA1 is complete (len == 20), assume note object
a7e7eff6 JH	323	* If object SHA1 is incomplete (len < 20), assume note subtree
23123aec JH	324	*/
	325	if (len <= 20) {
	326	unsigned char type = PTR_TYPE_NOTE;
	327	struct leaf_node l = (struct leaf_node )
	328	xcalloc(sizeof(struct leaf_node), 1);
a7e7eff6	329	hashcpy(l->key_sha1, object_sha1);
23123aec JH	330	hashcpy(l->val_sha1, entry.sha1);
23123aec JH	331	if (len < 20) {
488bdf2e JH	332	if (!S_ISDIR(entry.mode))
488bdf2e JH	333	continue; /* entry cannot be subtree */
23123aec JH	334	l->key_sha1[19] = (unsigned char) len;
	335	type = PTR_TYPE_SUBTREE;
	336	}
ef8db638	337	note_tree_insert(node, n, l, type);
23123aec JH	338	}
	339	}
	340	free(buf);
	341	}
	342
709f79b0	343	void init_notes(const char *notes_ref, int flags)
23123aec	344	{
a7e7eff6	345	unsigned char sha1[20], object_sha1[20];
23123aec JH	346	unsigned mode;
23123aec JH	347	struct leaf_node root_tree;
fd53c9eb	348
709f79b0 JH	349	assert(!initialized);
	350	initialized = 1;
	351
	352	if (!notes_ref)
	353	notes_ref = getenv(GIT_NOTES_REF_ENVIRONMENT);
	354	if (!notes_ref)
	355	notes_ref = notes_ref_name; /* value of core.notesRef config */
	356	if (!notes_ref)
	357	notes_ref = GIT_NOTES_DEFAULT_REF;
	358
	359	if (flags & NOTES_INIT_EMPTY \|\| !notes_ref \|\|
	360	read_ref(notes_ref, object_sha1))
fd53c9eb	361	return;
709f79b0 JH	362	if (get_tree_entry(object_sha1, "", sha1, &mode))
	363	die("Failed to read notes tree referenced by %s (%s)",
	364	notes_ref, object_sha1);
fd53c9eb	365
23123aec JH	366	hashclr(root_tree.key_sha1);
	367	hashcpy(root_tree.val_sha1, sha1);
	368	load_subtree(&root_tree, &root_node, 0);
fd53c9eb JS	369	}
fd53c9eb JS	370
a7e7eff6	371	static unsigned char lookup_notes(const unsigned char object_sha1)
fd53c9eb	372	{
a7e7eff6	373	struct leaf_node *found = note_tree_find(&root_node, 0, object_sha1);
23123aec JH	374	if (found)
	375	return found->val_sha1;
	376	return NULL;
fd53c9eb	377	}
a97a7468	378
27d57564 JH	379	void free_notes(void)
27d57564 JH	380	{
23123aec JH	381	note_tree_free(&root_node);
23123aec JH	382	memset(&root_node, 0, sizeof(struct int_node));
27d57564 JH	383	initialized = 0;
	384	}
	385
a7e7eff6	386	void format_note(const unsigned char object_sha1, struct strbuf sb,
c56fcc89	387	const char *output_encoding, int flags)
a97a7468 JS	388	{
a97a7468 JS	389	static const char utf8[] = "utf-8";
fd53c9eb	390	unsigned char *sha1;
a97a7468 JS	391	char msg, msg_p;
	392	unsigned long linelen, msglen;
	393	enum object_type type;
	394
709f79b0 JH	395	if (!initialized)
709f79b0 JH	396	init_notes(NULL, 0);
a97a7468	397
a7e7eff6	398	sha1 = lookup_notes(object_sha1);
fd53c9eb	399	if (!sha1)
a97a7468 JS	400	return;
	401
	402	if (!(msg = read_sha1_file(sha1, &type, &msglen)) \|\| !msglen \|\|
	403	type != OBJ_BLOB) {
	404	free(msg);
	405	return;
	406	}
	407
	408	if (output_encoding && *output_encoding &&
	409	strcmp(utf8, output_encoding)) {
	410	char *reencoded = reencode_string(msg, output_encoding, utf8);
	411	if (reencoded) {
	412	free(msg);
	413	msg = reencoded;
	414	msglen = strlen(msg);
	415	}
	416	}
	417
	418	/* we will end the annotation by a newline anyway */
	419	if (msglen && msg[msglen - 1] == '\n')
	420	msglen--;
	421
c56fcc89 JH	422	if (flags & NOTES_SHOW_HEADER)
c56fcc89 JH	423	strbuf_addstr(sb, "\nNotes:\n");
a97a7468 JS	424
	425	for (msg_p = msg; msg_p < msg + msglen; msg_p += linelen + 1) {
	426	linelen = strchrnul(msg_p, '\n') - msg_p;
	427
c56fcc89 JH	428	if (flags & NOTES_INDENT)
c56fcc89 JH	429	strbuf_addstr(sb, " ");
a97a7468 JS	430	strbuf_add(sb, msg_p, linelen);
	431	strbuf_addch(sb, '\n');
	432	}
	433
	434	free(msg);
	435	}