Initial commit for TizenHEADsubmit/2.0alpha/20130201.014617accepted/2.0alpha/20130201.0121062.0alpha

1 files changed, 452 insertions, 0 deletions

diff --git a/tree-walk.c b/tree-walk.c
new file mode 100644
index 0000000..67a9a0c
--- /dev/null
+++ b/tree-walk.c
@@ -0,0 +1,452 @@
+#include "cache.h"
+#include "tree-walk.h"
+#include "tree.h"
+
+static const char *get_mode(const char *str, unsigned int *modep)
+{
+	unsigned char c;
+	unsigned int mode = 0;
+
+	if (*str == ' ')
+		return NULL;
+
+	while ((c = *str++) != ' ') {
+		if (c < '0' || c > '7')
+			return NULL;
+		mode = (mode << 3) + (c - '0');
+	}
+	*modep = mode;
+	return str;
+}
+
+static void decode_tree_entry(struct tree_desc *desc, const char *buf, unsigned long size)
+{
+	const char *path;
+	unsigned int mode, len;
+
+	if (size < 24 || buf[size - 21])
+		die("corrupt tree file");
+
+	path = get_mode(buf, &mode);
+	if (!path || !*path)
+		die("corrupt tree file");
+	len = strlen(path) + 1;
+
+	/* Initialize the descriptor entry */
+	desc->entry.path = path;
+	desc->entry.mode = mode;
+	desc->entry.sha1 = (const unsigned char *)(path + len);
+}
+
+void init_tree_desc(struct tree_desc *desc, const void *buffer, unsigned long size)
+{
+	desc->buffer = buffer;
+	desc->size = size;
+	if (size)
+		decode_tree_entry(desc, buffer, size);
+}
+
+void *fill_tree_descriptor(struct tree_desc *desc, const unsigned char *sha1)
+{
+	unsigned long size = 0;
+	void *buf = NULL;
+
+	if (sha1) {
+		buf = read_object_with_reference(sha1, tree_type, &size, NULL);
+		if (!buf)
+			die("unable to read tree %s", sha1_to_hex(sha1));
+	}
+	init_tree_desc(desc, buf, size);
+	return buf;
+}
+
+static void entry_clear(struct name_entry *a)
+{
+	memset(a, 0, sizeof(*a));
+}
+
+static void entry_extract(struct tree_desc *t, struct name_entry *a)
+{
+	*a = t->entry;
+}
+
+void update_tree_entry(struct tree_desc *desc)
+{
+	const void *buf = desc->buffer;
+	const unsigned char *end = desc->entry.sha1 + 20;
+	unsigned long size = desc->size;
+	unsigned long len = end - (const unsigned char *)buf;
+
+	if (size < len)
+		die("corrupt tree file");
+	buf = end;
+	size -= len;
+	desc->buffer = buf;
+	desc->size = size;
+	if (size)
+		decode_tree_entry(desc, buf, size);
+}
+
+int tree_entry(struct tree_desc *desc, struct name_entry *entry)
+{
+	if (!desc->size)
+		return 0;
+
+	*entry = desc->entry;
+	update_tree_entry(desc);
+	return 1;
+}
+
+void setup_traverse_info(struct traverse_info *info, const char *base)
+{
+	int pathlen = strlen(base);
+	static struct traverse_info dummy;
+
+	memset(info, 0, sizeof(*info));
+	if (pathlen && base[pathlen-1] == '/')
+		pathlen--;
+	info->pathlen = pathlen ? pathlen + 1 : 0;
+	info->name.path = base;
+	info->name.sha1 = (void *)(base + pathlen + 1);
+	if (pathlen)
+		info->prev = &dummy;
+}
+
+char *make_traverse_path(char *path, const struct traverse_info *info, const struct name_entry *n)
+{
+	int len = tree_entry_len(n->path, n->sha1);
+	int pathlen = info->pathlen;
+
+	path[pathlen + len] = 0;
+	for (;;) {
+		memcpy(path + pathlen, n->path, len);
+		if (!pathlen)
+			break;
+		path[--pathlen] = '/';
+		n = &info->name;
+		len = tree_entry_len(n->path, n->sha1);
+		info = info->prev;
+		pathlen -= len;
+	}
+	return path;
+}
+
+struct tree_desc_skip {
+	struct tree_desc_skip *prev;
+	const void *ptr;
+};
+
+struct tree_desc_x {
+	struct tree_desc d;
+	struct tree_desc_skip *skip;
+};
+
+static int name_compare(const char *a, int a_len,
+			const char *b, int b_len)
+{
+	int len = (a_len < b_len) ? a_len : b_len;
+	int cmp = memcmp(a, b, len);
+	if (cmp)
+		return cmp;
+	return (a_len - b_len);
+}
+
+static int check_entry_match(const char *a, int a_len, const char *b, int b_len)
+{
+	/*
+	 * The caller wants to pick *a* from a tree or nothing.
+	 * We are looking at *b* in a tree.
+	 *
+	 * (0) If a and b are the same name, we are trivially happy.
+	 *
+	 * There are three possibilities where *a* could be hiding
+	 * behind *b*.
+	 *
+	 * (1) *a* == "t",   *b* == "ab"  i.e. *b* sorts earlier than *a* no
+	 *                                matter what.
+	 * (2) *a* == "t",   *b* == "t-2" and "t" is a subtree in the tree;
+	 * (3) *a* == "t-2", *b* == "t"   and "t-2" is a blob in the tree.
+	 *
+	 * Otherwise we know *a* won't appear in the tree without
+	 * scanning further.
+	 */
+
+	int cmp = name_compare(a, a_len, b, b_len);
+
+	/* Most common case first -- reading sync'd trees */
+	if (!cmp)
+		return cmp;
+
+	if (0 < cmp) {
+		/* a comes after b; it does not matter if it is case (3)
+		if (b_len < a_len && !memcmp(a, b, b_len) && a[b_len] < '/')
+			return 1;
+		*/
+		return 1; /* keep looking */
+	}
+
+	/* b comes after a; are we looking at case (2)? */
+	if (a_len < b_len && !memcmp(a, b, a_len) && b[a_len] < '/')
+		return 1; /* keep looking */
+
+	return -1; /* a cannot appear in the tree */
+}
+
+/*
+ * From the extended tree_desc, extract the first name entry, while
+ * paying attention to the candidate "first" name.  Most importantly,
+ * when looking for an entry, if there are entries that sorts earlier
+ * in the tree object representation than that name, skip them and
+ * process the named entry first.  We will remember that we haven't
+ * processed the first entry yet, and in the later call skip the
+ * entry we processed early when update_extended_entry() is called.
+ *
+ * E.g. if the underlying tree object has these entries:
+ *
+ *    blob    "t-1"
+ *    blob    "t-2"
+ *    tree    "t"
+ *    blob    "t=1"
+ *
+ * and the "first" asks for "t", remember that we still need to
+ * process "t-1" and "t-2" but extract "t".  After processing the
+ * entry "t" from this call, the caller will let us know by calling
+ * update_extended_entry() that we can remember "t" has been processed
+ * already.
+ */
+
+static void extended_entry_extract(struct tree_desc_x *t,
+				   struct name_entry *a,
+				   const char *first,
+				   int first_len)
+{
+	const char *path;
+	int len;
+	struct tree_desc probe;
+	struct tree_desc_skip *skip;
+
+	/*
+	 * Extract the first entry from the tree_desc, but skip the
+	 * ones that we already returned in earlier rounds.
+	 */
+	while (1) {
+		if (!t->d.size) {
+			entry_clear(a);
+			break; /* not found */
+		}
+		entry_extract(&t->d, a);
+		for (skip = t->skip; skip; skip = skip->prev)
+			if (a->path == skip->ptr)
+				break; /* found */
+		if (!skip)
+			break;
+		/* We have processed this entry already. */
+		update_tree_entry(&t->d);
+	}
+
+	if (!first || !a->path)
+		return;
+
+	/*
+	 * The caller wants "first" from this tree, or nothing.
+	 */
+	path = a->path;
+	len = tree_entry_len(a->path, a->sha1);
+	switch (check_entry_match(first, first_len, path, len)) {
+	case -1:
+		entry_clear(a);
+	case 0:
+		return;
+	default:
+		break;
+	}
+
+	/*
+	 * We need to look-ahead -- we suspect that a subtree whose
+	 * name is "first" may be hiding behind the current entry "path".
+	 */
+	probe = t->d;
+	while (probe.size) {
+		entry_extract(&probe, a);
+		path = a->path;
+		len = tree_entry_len(a->path, a->sha1);
+		switch (check_entry_match(first, first_len, path, len)) {
+		case -1:
+			entry_clear(a);
+		case 0:
+			return;
+		default:
+			update_tree_entry(&probe);
+			break;
+		}
+		/* keep looking */
+	}
+	entry_clear(a);
+}
+
+static void update_extended_entry(struct tree_desc_x *t, struct name_entry *a)
+{
+	if (t->d.entry.path == a->path) {
+		update_tree_entry(&t->d);
+	} else {
+		/* we have returned this entry early */
+		struct tree_desc_skip *skip = xmalloc(sizeof(*skip));
+		skip->ptr = a->path;
+		skip->prev = t->skip;
+		t->skip = skip;
+	}
+}
+
+static void free_extended_entry(struct tree_desc_x *t)
+{
+	struct tree_desc_skip *p, *s;
+
+	for (s = t->skip; s; s = p) {
+		p = s->prev;
+		free(s);
+	}
+}
+
+int traverse_trees(int n, struct tree_desc *t, struct traverse_info *info)
+{
+	int ret = 0;
+	struct name_entry *entry = xmalloc(n*sizeof(*entry));
+	int i;
+	struct tree_desc_x *tx = xcalloc(n, sizeof(*tx));
+
+	for (i = 0; i < n; i++)
+		tx[i].d = t[i];
+
+	for (;;) {
+		unsigned long mask, dirmask;
+		const char *first = NULL;
+		int first_len = 0;
+		struct name_entry *e;
+		int len;
+
+		for (i = 0; i < n; i++) {
+			e = entry + i;
+			extended_entry_extract(tx + i, e, NULL, 0);
+		}
+
+		/*
+		 * A tree may have "t-2" at the current location even
+		 * though it may have "t" that is a subtree behind it,
+		 * and another tree may return "t".  We want to grab
+		 * all "t" from all trees to match in such a case.
+		 */
+		for (i = 0; i < n; i++) {
+			e = entry + i;
+			if (!e->path)
+				continue;
+			len = tree_entry_len(e->path, e->sha1);
+			if (!first) {
+				first = e->path;
+				first_len = len;
+				continue;
+			}
+			if (name_compare(e->path, len, first, first_len) < 0) {
+				first = e->path;
+				first_len = len;
+			}
+		}
+
+		if (first) {
+			for (i = 0; i < n; i++) {
+				e = entry + i;
+				extended_entry_extract(tx + i, e, first, first_len);
+				/* Cull the ones that are not the earliest */
+				if (!e->path)
+					continue;
+				len = tree_entry_len(e->path, e->sha1);
+				if (name_compare(e->path, len, first, first_len))
+					entry_clear(e);
+			}
+		}
+
+		/* Now we have in entry[i] the earliest name from the trees */
+		mask = 0;
+		dirmask = 0;
+		for (i = 0; i < n; i++) {
+			if (!entry[i].path)
+				continue;
+			mask |= 1ul << i;
+			if (S_ISDIR(entry[i].mode))
+				dirmask |= 1ul << i;
+		}
+		if (!mask)
+			break;
+		ret = info->fn(n, mask, dirmask, entry, info);
+		if (ret < 0)
+			break;
+		mask &= ret;
+		ret = 0;
+		for (i = 0; i < n; i++)
+			if (mask & (1ul << i))
+				update_extended_entry(tx + i, entry + i);
+	}
+	free(entry);
+	for (i = 0; i < n; i++)
+		free_extended_entry(tx + i);
+	free(tx);
+	return ret;
+}
+
+static int find_tree_entry(struct tree_desc *t, const char *name, unsigned char *result, unsigned *mode)
+{
+	int namelen = strlen(name);
+	while (t->size) {
+		const char *entry;
+		const unsigned char *sha1;
+		int entrylen, cmp;
+
+		sha1 = tree_entry_extract(t, &entry, mode);
+		update_tree_entry(t);
+		entrylen = tree_entry_len(entry, sha1);
+		if (entrylen > namelen)
+			continue;
+		cmp = memcmp(name, entry, entrylen);
+		if (cmp > 0)
+			continue;
+		if (cmp < 0)
+			break;
+		if (entrylen == namelen) {
+			hashcpy(result, sha1);
+			return 0;
+		}
+		if (name[entrylen] != '/')
+			continue;
+		if (!S_ISDIR(*mode))
+			break;
+		if (++entrylen == namelen) {
+			hashcpy(result, sha1);
+			return 0;
+		}
+		return get_tree_entry(sha1, name + entrylen, result, mode);
+	}
+	return -1;
+}
+
+int get_tree_entry(const unsigned char *tree_sha1, const char *name, unsigned char *sha1, unsigned *mode)
+{
+	int retval;
+	void *tree;
+	unsigned long size;
+	struct tree_desc t;
+	unsigned char root[20];
+
+	tree = read_object_with_reference(tree_sha1, tree_type, &size, root);
+	if (!tree)
+		return -1;
+
+	if (name[0] == '\0') {
+		hashcpy(sha1, root);
+		free(tree);
+		return 0;
+	}
+
+	init_tree_desc(&t, tree, size);
+	retval = find_tree_entry(&t, name, sha1, mode);
+	free(tree);
+	return retval;
+}