Merge branch 'kn/cat-file-literally'

Add the "--allow-unknown-type" option to "cat-file" to allow
inspecting loose objects of an experimental or a broken type.

* kn/cat-file-literally:
  t1006: add tests for git cat-file --allow-unknown-type
  cat-file: teach cat-file a '--allow-unknown-type' option
  cat-file: make the options mutually exclusive
  sha1_file: support reading from a loose object of unknown type

1 files changed, 106 insertions, 22 deletions

diff --git a/sha1_file.c b/sha1_file.c
index 866021b..ccc6dac 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -1564,6 +1564,40 @@ int unpack_sha1_header(git_zstream *stream, unsigned char *map, unsigned long ma
 	return git_inflate(stream, 0);
 }
 
+static int unpack_sha1_header_to_strbuf(git_zstream *stream, unsigned char *map,
+					unsigned long mapsize, void *buffer,
+					unsigned long bufsiz, struct strbuf *header)
+{
+	int status;
+
+	status = unpack_sha1_header(stream, map, mapsize, buffer, bufsiz);
+
+	/*
+	 * Check if entire header is unpacked in the first iteration.
+	 */
+	if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
+		return 0;
+
+	/*
+	 * buffer[0..bufsiz] was not large enough.  Copy the partial
+	 * result out to header, and then append the result of further
+	 * reading the stream.
+	 */
+	strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
+	stream->next_out = buffer;
+	stream->avail_out = bufsiz;
+
+	do {
+		status = git_inflate(stream, 0);
+		strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
+		if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
+			return 0;
+		stream->next_out = buffer;
+		stream->avail_out = bufsiz;
+	} while (status != Z_STREAM_END);
+	return -1;
+}
+
 static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
 {
 	int bytes = strlen(buffer) + 1;
@@ -1614,27 +1648,38 @@ static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long s
  * too permissive for what we want to check. So do an anal
  * object header parse by hand.
  */
-int parse_sha1_header(const char *hdr, unsigned long *sizep)
+static int parse_sha1_header_extended(const char *hdr, struct object_info *oi,
+			       unsigned int flags)
 {
-	char type[10];
-	int i;
+	const char *type_buf = hdr;
 	unsigned long size;
+	int type, type_len = 0;
 
 	/*
-	 * The type can be at most ten bytes (including the
-	 * terminating '\0' that we add), and is followed by
+	 * The type can be of any size but is followed by
 	 * a space.
 	 */
-	i = 0;
 	for (;;) {
 		char c = *hdr++;
 		if (c == ' ')
 			break;
-		type[i++] = c;
-		if (i >= sizeof(type))
-			return -1;
+		type_len++;
 	}
-	type[i] = 0;
+
+	type = type_from_string_gently(type_buf, type_len, 1);
+	if (oi->typename)
+		strbuf_add(oi->typename, type_buf, type_len);
+	/*
+	 * Set type to 0 if its an unknown object and
+	 * we're obtaining the type using '--allow-unkown-type'
+	 * option.
+	 */
+	if ((flags & LOOKUP_UNKNOWN_OBJECT) && (type < 0))
+		type = 0;
+	else if (type < 0)
+		die("invalid object type");
+	if (oi->typep)
+		*oi->typep = type;
 
 	/*
 	 * The length must follow immediately, and be in canonical
@@ -1652,12 +1697,24 @@ int parse_sha1_header(const char *hdr, unsigned long *sizep)
 			size = size * 10 + c;
 		}
 	}
-	*sizep = size;
+
+	if (oi->sizep)
+		*oi->sizep = size;
 
 	/*
 	 * The length must be followed by a zero byte
 	 */
-	return *hdr ? -1 : type_from_string(type);
+	return *hdr ? -1 : type;
+}
+
+int parse_sha1_header(const char *hdr, unsigned long *sizep)
+{
+	struct object_info oi;
+
+	oi.sizep = sizep;
+	oi.typename = NULL;
+	oi.typep = NULL;
+	return parse_sha1_header_extended(hdr, &oi, LOOKUP_REPLACE_OBJECT);
 }
 
 static void *unpack_sha1_file(void *map, unsigned long mapsize, enum object_type *type, unsigned long *size, const unsigned char *sha1)
@@ -2522,13 +2579,15 @@ struct packed_git *find_sha1_pack(const unsigned char *sha1,
 }
 
 static int sha1_loose_object_info(const unsigned char *sha1,
-				  struct object_info *oi)
+				  struct object_info *oi,
+				  int flags)
 {
-	int status;
-	unsigned long mapsize, size;
+	int status = 0;
+	unsigned long mapsize;
 	void *map;
 	git_zstream stream;
 	char hdr[32];
+	struct strbuf hdrbuf = STRBUF_INIT;
 
 	if (oi->delta_base_sha1)
 		hashclr(oi->delta_base_sha1);
@@ -2541,7 +2600,7 @@ static int sha1_loose_object_info(const unsigned char *sha1,
 	 * return value implicitly indicates whether the
 	 * object even exists.
 	 */
-	if (!oi->typep && !oi->sizep) {
+	if (!oi->typep && !oi->typename && !oi->sizep) {
 		struct stat st;
 		if (stat_sha1_file(sha1, &st) < 0)
 			return -1;
@@ -2555,17 +2614,26 @@ static int sha1_loose_object_info(const unsigned char *sha1,
 		return -1;
 	if (oi->disk_sizep)
 		*oi->disk_sizep = mapsize;
-	if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
+	if ((flags & LOOKUP_UNKNOWN_OBJECT)) {
+		if (unpack_sha1_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
+			status = error("unable to unpack %s header with --allow-unknown-type",
+				       sha1_to_hex(sha1));
+	} else if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
 		status = error("unable to unpack %s header",
 			       sha1_to_hex(sha1));
-	else if ((status = parse_sha1_header(hdr, &size)) < 0)
+	if (status < 0)
+		; /* Do nothing */
+	else if (hdrbuf.len) {
+		if ((status = parse_sha1_header_extended(hdrbuf.buf, oi, flags)) < 0)
+			status = error("unable to parse %s header with --allow-unknown-type",
+				       sha1_to_hex(sha1));
+	} else if ((status = parse_sha1_header_extended(hdr, oi, flags)) < 0)
 		status = error("unable to parse %s header", sha1_to_hex(sha1));
-	else if (oi->sizep)
-		*oi->sizep = size;
 	git_inflate_end(&stream);
 	munmap(map, mapsize);
-	if (oi->typep)
+	if (status && oi->typep)
 		*oi->typep = status;
+	strbuf_release(&hdrbuf);
 	return 0;
 }
 
@@ -2574,6 +2642,7 @@ int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi,
 	struct cached_object *co;
 	struct pack_entry e;
 	int rtype;
+	enum object_type real_type;
 	const unsigned char *real = lookup_replace_object_extended(sha1, flags);
 
 	co = find_cached_object(real);
@@ -2586,13 +2655,15 @@ int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi,
 			*(oi->disk_sizep) = 0;
 		if (oi->delta_base_sha1)
 			hashclr(oi->delta_base_sha1);
+		if (oi->typename)
+			strbuf_addstr(oi->typename, typename(co->type));
 		oi->whence = OI_CACHED;
 		return 0;
 	}
 
 	if (!find_pack_entry(real, &e)) {
 		/* Most likely it's a loose object. */
-		if (!sha1_loose_object_info(real, oi)) {
+		if (!sha1_loose_object_info(real, oi, flags)) {
 			oi->whence = OI_LOOSE;
 			return 0;
 		}
@@ -2603,9 +2674,18 @@ int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi,
 			return -1;
 	}
 
+	/*
+	 * packed_object_info() does not follow the delta chain to
+	 * find out the real type, unless it is given oi->typep.
+	 */
+	if (oi->typename && !oi->typep)
+		oi->typep = &real_type;
+
 	rtype = packed_object_info(e.p, e.offset, oi);
 	if (rtype < 0) {
 		mark_bad_packed_object(e.p, real);
+		if (oi->typep == &real_type)
+			oi->typep = NULL;
 		return sha1_object_info_extended(real, oi, 0);
 	} else if (in_delta_base_cache(e.p, e.offset)) {
 		oi->whence = OI_DBCACHED;
@@ -2616,6 +2696,10 @@ int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi,
 		oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
 					 rtype == OBJ_OFS_DELTA);
 	}
+	if (oi->typename)
+		strbuf_addstr(oi->typename, typename(*oi->typep));
+	if (oi->typep == &real_type)
+		oi->typep = NULL;
 
 	return 0;
 }