Squashed 'third_party/git/' content from commit cb71568594

git-subtree-dir: third_party/git
git-subtree-split: cb715685942260375e1eb8153b0768a376e4ece7

1 files changed, 106 insertions, 0 deletions

diff --git a/pack.h b/pack.h
new file mode 100644
index 000000000000..9fc0945ac916
--- /dev/null
+++ b/pack.h
@@ -0,0 +1,106 @@
+#ifndef PACK_H
+#define PACK_H
+
+#include "object.h"
+#include "csum-file.h"
+
+struct repository;
+
+/*
+ * Packed object header
+ */
+#define PACK_SIGNATURE 0x5041434b	/* "PACK" */
+#define PACK_VERSION 2
+#define pack_version_ok(v) ((v) == htonl(2) || (v) == htonl(3))
+struct pack_header {
+	uint32_t hdr_signature;
+	uint32_t hdr_version;
+	uint32_t hdr_entries;
+};
+
+/*
+ * The first four bytes of index formats later than version 1 should
+ * start with this signature, as all older git binaries would find this
+ * value illegal and abort reading the file.
+ *
+ * This is the case because the number of objects in a packfile
+ * cannot exceed 1,431,660,000 as every object would need at least
+ * 3 bytes of data and the overall packfile cannot exceed 4 GiB with
+ * version 1 of the index file due to the offsets limited to 32 bits.
+ * Clearly the signature exceeds this maximum.
+ *
+ * Very old git binaries will also compare the first 4 bytes to the
+ * next 4 bytes in the index and abort with a "non-monotonic index"
+ * error if the second 4 byte word is smaller than the first 4
+ * byte word.  This would be true in the proposed future index
+ * format as idx_signature would be greater than idx_version.
+ */
+#define PACK_IDX_SIGNATURE 0xff744f63	/* "\377tOc" */
+
+struct pack_idx_option {
+	unsigned flags;
+	/* flag bits */
+#define WRITE_IDX_VERIFY 01 /* verify only, do not write the idx file */
+#define WRITE_IDX_STRICT 02
+
+	uint32_t version;
+	uint32_t off32_limit;
+
+	/*
+	 * List of offsets that would fit within off32_limit but
+	 * need to be written out as 64-bit entity for byte-for-byte
+	 * verification.
+	 */
+	int anomaly_alloc, anomaly_nr;
+	uint32_t *anomaly;
+};
+
+void reset_pack_idx_option(struct pack_idx_option *);
+
+/*
+ * Packed object index header
+ */
+struct pack_idx_header {
+	uint32_t idx_signature;
+	uint32_t idx_version;
+};
+
+/*
+ * Common part of object structure used for write_idx_file
+ */
+struct pack_idx_entry {
+	struct object_id oid;
+	uint32_t crc32;
+	off_t offset;
+};
+
+
+struct progress;
+/* Note, the data argument could be NULL if object type is blob */
+typedef int (*verify_fn)(const struct object_id *, enum object_type, unsigned long, void*, int*);
+
+const char *write_idx_file(const char *index_name, struct pack_idx_entry **objects, int nr_objects, const struct pack_idx_option *, const unsigned char *sha1);
+int check_pack_crc(struct packed_git *p, struct pack_window **w_curs, off_t offset, off_t len, unsigned int nr);
+int verify_pack_index(struct packed_git *);
+int verify_pack(struct repository *, struct packed_git *, verify_fn fn, struct progress *, uint32_t);
+off_t write_pack_header(struct hashfile *f, uint32_t);
+void fixup_pack_header_footer(int, unsigned char *, const char *, uint32_t, unsigned char *, off_t);
+char *index_pack_lockfile(int fd);
+
+/*
+ * The "hdr" output buffer should be at least this big, which will handle sizes
+ * up to 2^67.
+ */
+#define MAX_PACK_OBJECT_HEADER 10
+int encode_in_pack_object_header(unsigned char *hdr, int hdr_len,
+				 enum object_type, uintmax_t);
+
+#define PH_ERROR_EOF		(-1)
+#define PH_ERROR_PACK_SIGNATURE	(-2)
+#define PH_ERROR_PROTOCOL	(-3)
+int read_pack_header(int fd, struct pack_header *);
+
+struct hashfile *create_tmp_packfile(char **pack_tmp_name);
+void finish_tmp_packfile(struct strbuf *name_buffer, const char *pack_tmp_name, struct pack_idx_entry **written_list, uint32_t nr_written, struct pack_idx_option *pack_idx_opts, unsigned char sha1[]);
+
+#endif