X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=sha1_name.c;h=bf8f0f0e1feef55ba6be764f60815d15036efa4e;hb=ee34518d629331dadd58b1a75294369d679eda8b;hp=4e9a052333dcbb538866766f68b4fe18f615fe4d;hpb=f51248eb482a7a0feacb04d02119c94d35845975;p=git.git

diff --git a/sha1_name.c b/sha1_name.c
index 4e9a0523..bf8f0f0e 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -1,5 +1,8 @@
 #include "cache.h"
+#include "tag.h"
 #include "commit.h"
+#include "tree.h"
+#include "blob.h"
 
 static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
 {
@@ -200,6 +203,31 @@ const char *find_unique_abbrev(const unsigned char *sha1, int len)
 	return NULL;
 }
 
+static int ambiguous_path(const char *path, int len)
+{
+	int slash = 1;
+	int cnt;
+
+	for (cnt = 0; cnt < len; cnt++) {
+		switch (*path++) {
+		case '\0':
+			break;
+		case '/':
+			if (slash)
+				break;
+			slash = 1;
+			continue;
+		case '.':
+			continue;
+		default:
+			slash = 0;
+			continue;
+		}
+		return slash;
+	}
+	return slash;
+}
+
 static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 {
 	static const char *prefix[] = {
@@ -210,17 +238,47 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 		NULL
 	};
 	const char **p;
+	int found = 0;
 
 	if (len == 40 && !get_sha1_hex(str, sha1))
 		return 0;
 
+	/* Accept only unambiguous ref paths. */
+	if (ambiguous_path(str, len))
+		return -1;
+
 	for (p = prefix; *p; p++) {
 		char *pathname = git_path("%s/%.*s", *p, len, str);
-		if (!read_ref(pathname, sha1))
-			return 0;
-	}
 
-	return -1;
+		if (!read_ref(pathname, sha1)) {
+			/* Must be unique; i.e. when heads/foo and
+			 * tags/foo are both present, reject "foo".
+			 */
+			if (1 < found++)
+				return -1;
+		}
+
+		/* We want to allow .git/description file and
+		 * "description" branch to exist at the same time.
+		 * "git-rev-parse description" should silently skip
+		 * .git/description file as a candidate for
+		 * get_sha1().  However, having garbage file anywhere
+		 * under refs/ is not OK, and we would not have caught
+		 * ambiguous heads and tags with the above test.
+		 */
+		else if (**p && !access(pathname, F_OK)) {
+			/* Garbage exists under .git/refs */
+			return error("garbage ref found '%s'", pathname);
+		}
+	}
+	switch (found) {
+	case 0:
+		return -1;
+	case 1:
+		return 0;
+	default:
+		return error("ambiguous refname '%.*s'", len, str);
+	}
 }
 
 static int get_sha1_1(const char *name, int len, unsigned char *sha1);
@@ -274,6 +332,84 @@ static int get_nth_ancestor(const char *name, int len,
 	return 0;
 }
 
+static int peel_onion(const char *name, int len, unsigned char *sha1)
+{
+	unsigned char outer[20];
+	const char *sp;
+	const char *type_string = NULL;
+	struct object *o;
+
+	/*
+	 * "ref^{type}" dereferences ref repeatedly until you cannot
+	 * dereference anymore, or you get an object of given type,
+	 * whichever comes first.  "ref^{}" means just dereference
+	 * tags until you get a non-tag.  "ref^0" is a shorthand for
+	 * "ref^{commit}".  "commit^{tree}" could be used to find the
+	 * top-level tree of the given commit.
+	 */
+	if (len < 4 || name[len-1] != '}')
+		return -1;
+
+	for (sp = name + len - 1; name <= sp; sp--) {
+		int ch = *sp;
+		if (ch == '{' && name < sp && sp[-1] == '^')
+			break;
+	}
+	if (sp <= name)
+		return -1;
+
+	sp++; /* beginning of type name, or closing brace for empty */
+	if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
+		type_string = commit_type;
+	else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
+		type_string = tree_type;
+	else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
+		type_string = blob_type;
+	else if (sp[0] == '}')
+		type_string = NULL;
+	else
+		return -1;
+
+	if (get_sha1_1(name, sp - name - 2, outer))
+		return -1;
+
+	o = parse_object(outer);
+	if (!o)
+		return -1;
+	if (!type_string) {
+		o = deref_tag(o, name, sp - name - 2);
+		if (!o || (!o->parsed && !parse_object(o->sha1)))
+			return -1;
+		memcpy(sha1, o->sha1, 20);
+	}
+	else {
+		/* At this point, the syntax look correct, so
+		 * if we do not get the needed object, we should
+		 * barf.
+		 */
+
+		while (1) {
+			if (!o || (!o->parsed && !parse_object(o->sha1)))
+				return -1;
+			if (o->type == type_string) {
+				memcpy(sha1, o->sha1, 20);
+				return 0;
+			}
+			if (o->type == tag_type)
+				o = ((struct tag*) o)->tagged;
+			else if (o->type == commit_type)
+				o = &(((struct commit *) o)->tree->object);
+			else
+				return error("%.*s: expected %s type, but the object dereferences to %s type",
+					     len, name, type_string,
+					     o->type);
+			if (!o->parsed)
+				parse_object(o->sha1);
+		}
+	}
+	return 0;
+}
+
 static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 {
 	int parent, ret;
@@ -315,6 +451,10 @@ static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 		return get_nth_ancestor(name, len1, sha1, parent);
 	}
 
+	ret = peel_onion(name, len, sha1);
+	if (!ret)
+		return 0;
+
 	ret = get_sha1_basic(name, len, sha1);
 	if (!ret)
 		return 0;