[PATCH 05/32] pack-write: add functions for creating simple packs

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

These are ripoffs from pack-objects and do not do deltas at all.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 pack-write.c |   87 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 pack.h       |   17 +++++++++++
 2 files changed, 104 insertions(+), 0 deletions(-)

diff --git a/pack-write.c b/pack-write.c
index cc7761e..2b71bd2 100644
--- a/pack-write.c
+++ b/pack-write.c
@@ -305,3 +305,90 @@ unsigned long compress_object(void **pptr, unsigned long size)
 
 	return stream.total_out;
 }
+
+int create_pack(struct simple_pack *pack)
+{
+	char tmpname[PATH_MAX];
+	struct pack_header hdr;
+
+	if (pack->fd <= 0) {
+		pack->fd = odb_mkstemp(tmpname, sizeof(tmpname), "pack/tmp_pack_XXXXXX");
+		pack->pack_tmp_name = xstrdup(tmpname);
+	}
+	pack->f = sha1fd(pack->fd, pack->pack_tmp_name ? pack->pack_tmp_name : "<unknown>");
+
+	if (pack->nr_objects) {
+		int pointer_size = sizeof(struct pack_idx_entry*) * pack->nr_objects;
+		int item_size = sizeof(struct pack_idx_entry) * pack->nr_objects;
+		void *buf = xmalloc(item_size + pointer_size);
+		pack->written_list = buf;
+		pack->written_items = (void*)(((char*)buf) + pointer_size);
+	}
+
+	hdr.hdr_signature = htonl(PACK_SIGNATURE);
+	hdr.hdr_version = htonl(PACK_VERSION);
+	hdr.hdr_entries = htonl(pack->nr_objects);
+	sha1write(pack->f, &hdr, sizeof(hdr));
+	if (pack->written_list)
+		pack->offset = sizeof(hdr);
+
+	return 0;
+}
+
+int write_object_to_pack(struct simple_pack *pack,
+			 const unsigned char *sha1,
+			 void *buf,
+			 unsigned long size,
+			 enum object_type type)
+{
+	unsigned long datalen;
+	unsigned hdrlen;
+	unsigned char header[10];
+
+	datalen = compress_object(&buf, size);
+	hdrlen = encode_in_pack_object_header(type, size, header);
+	if (pack->written_list)
+		crc32_begin(pack->f);
+	sha1write(pack->f, header, hdrlen);
+	sha1write(pack->f, buf, datalen);
+	free(buf);
+
+	if (pack->written_list) {
+		struct pack_idx_entry *e;
+
+		e = pack->written_list[pack->nr_written] = pack->written_items;
+		e->crc32 = crc32_end(pack->f);
+		hashcpy(e->sha1, sha1);
+		e->offset = pack->offset;
+		pack->offset += datalen+hdrlen;
+	}
+	pack->nr_written++;
+	pack->written_items++;
+
+	return 0;
+}
+
+int close_pack(struct simple_pack *pack)
+{
+	sha1close(pack->f, pack->sha1, CSUM_CLOSE);
+	if (pack->written_list) {
+		char tmpname[PATH_MAX];
+		const char *idx_tmp_name;
+
+		idx_tmp_name = write_idx_file(NULL, pack->written_list, pack->nr_written, pack->sha1);
+
+		snprintf(tmpname, sizeof(tmpname), "%s/pack/pack-%s.pack", get_object_directory(), sha1_to_hex(pack->sha1));
+		free_pack_by_name(tmpname);
+		if (adjust_shared_perm(pack->pack_tmp_name))
+			die_errno("unable to make temporary pack file readable");
+		if (rename(pack->pack_tmp_name, tmpname))
+			die_errno("unable to rename temporary pack file");
+		snprintf(tmpname, sizeof(tmpname), "%s/pack/pack-%s.idx", get_object_directory(), sha1_to_hex(pack->sha1));
+		if (rename(idx_tmp_name, tmpname))
+			die_errno("unable to rename temporary pack file");
+		free(pack->written_list);
+	}
+	if (pack->pack_tmp_name)
+		free(pack->pack_tmp_name);
+	return 0;
+}
diff --git a/pack.h b/pack.h
index 28a966b..a2e32c7 100644
--- a/pack.h
+++ b/pack.h
@@ -55,6 +55,19 @@ struct pack_idx_entry {
 	off_t offset;
 };
 
+struct simple_pack {
+	uint32_t nr_objects;
+	unsigned char sha1[20];
+
+	int fd;
+	struct sha1file *f;
+	uint32_t nr_written;
+	off_t offset;
+	char *pack_tmp_name;
+	struct pack_idx_entry **written_list;
+	struct pack_idx_entry *written_items;
+};
+
 extern const char *write_idx_file(const char *index_name, struct pack_idx_entry **objects, int nr_objects, unsigned char *sha1);
 extern int check_pack_crc(struct packed_git *p, struct pack_window **w_curs, off_t offset, off_t len, unsigned int nr);
 extern int verify_pack_index(struct packed_git *);
@@ -64,6 +77,10 @@ extern char *index_pack_lockfile(int fd);
 extern int encode_in_pack_object_header(enum object_type, uintmax_t, unsigned char *);
 extern unsigned long compress_object(void **, unsigned long size);
 
+extern int create_pack(struct simple_pack *);
+extern int write_object_to_pack(struct simple_pack *, const unsigned char *, void *, unsigned long, enum object_type);
+extern int close_pack(struct simple_pack *);
+
 #define PH_ERROR_EOF		(-1)
 #define PH_ERROR_PACK_SIGNATURE	(-2)
 #define PH_ERROR_PROTOCOL	(-3)
-- 
1.7.1.rc1.69.g24c2f7