--- /dev/null
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#ifndef INCLUDE_pack_h__
+#define INCLUDE_pack_h__
+
+#include "common.h"
+
+#include "git2/oid.h"
+
+#include "array.h"
+#include "map.h"
+#include "mwindow.h"
+#include "odb.h"
+#include "offmap.h"
+#include "oidmap.h"
+#include "zstream.h"
+#include "oid.h"
+
+/**
+ * Function type for callbacks from git_pack_foreach_entry_offset.
+ */
+typedef int git_pack_foreach_entry_offset_cb(
+ const git_oid *id,
+ off64_t offset,
+ void *payload);
+
+#define GIT_PACK_FILE_MODE 0444
+
+#define PACK_SIGNATURE 0x5041434b /* "PACK" */
+#define PACK_VERSION 2
+#define pack_version_ok(v) ((v) == htonl(2))
+struct git_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 git_pack_idx_header {
+ uint32_t idx_signature;
+ uint32_t idx_version;
+};
+
+typedef struct git_pack_cache_entry {
+ size_t last_usage; /* enough? */
+ git_atomic32 refcount;
+ git_rawobj raw;
+} git_pack_cache_entry;
+
+struct pack_chain_elem {
+ off64_t base_key;
+ off64_t offset;
+ size_t size;
+ git_object_t type;
+};
+
+typedef git_array_t(struct pack_chain_elem) git_dependency_chain;
+
+#define GIT_PACK_CACHE_MEMORY_LIMIT 16 * 1024 * 1024
+#define GIT_PACK_CACHE_SIZE_LIMIT 1024 * 1024 /* don't bother caching anything over 1MB */
+
+typedef struct {
+ size_t memory_used;
+ size_t memory_limit;
+ size_t use_ctr;
+ git_mutex lock;
+ git_offmap *entries;
+} git_pack_cache;
+
+struct git_pack_file {
+ git_mwindow_file mwf;
+ git_map index_map;
+ git_mutex lock; /* protect updates to index_map */
+ git_atomic32 refcount;
+
+ uint32_t num_objects;
+ uint32_t num_bad_objects;
+ git_oid *bad_object_sha1; /* array of git_oid */
+
+ int index_version;
+ git_time_t mtime;
+ unsigned pack_local:1, pack_keep:1, has_cache:1;
+ git_oidmap *idx_cache;
+ unsigned char **oids;
+
+ git_pack_cache bases; /* delta base cache */
+
+ time_t last_freshen; /* last time the packfile was freshened */
+
+ /* something like ".git/objects/pack/xxxxx.pack" */
+ char pack_name[GIT_FLEX_ARRAY]; /* more */
+};
+
+/**
+ * Return the position where an OID (or a prefix) would be inserted within the
+ * OID Lookup Table of an .idx file. This performs binary search between the lo
+ * and hi indices.
+ *
+ * The stride parameter is provided because .idx files version 1 store the OIDs
+ * interleaved with the 4-byte file offsets of the objects within the .pack
+ * file (stride = 24), whereas files with version 2 store them in a contiguous
+ * flat array (stride = 20).
+ */
+int git_pack__lookup_sha1(const void *oid_lookup_table, size_t stride, unsigned lo,
+ unsigned hi, const unsigned char *oid_prefix);
+
+struct git_pack_entry {
+ off64_t offset;
+ git_oid sha1;
+ struct git_pack_file *p;
+};
+
+typedef struct git_packfile_stream {
+ off64_t curpos;
+ int done;
+ git_zstream zstream;
+ struct git_pack_file *p;
+ git_mwindow *mw;
+} git_packfile_stream;
+
+int git_packfile__object_header(size_t *out, unsigned char *hdr, size_t size, git_object_t type);
+
+int git_packfile__name(char **out, const char *path);
+
+int git_packfile_unpack_header(
+ size_t *size_p,
+ git_object_t *type_p,
+ struct git_pack_file *p,
+ git_mwindow **w_curs,
+ off64_t *curpos);
+
+int git_packfile_resolve_header(
+ size_t *size_p,
+ git_object_t *type_p,
+ struct git_pack_file *p,
+ off64_t offset);
+
+int git_packfile_unpack(git_rawobj *obj, struct git_pack_file *p, off64_t *obj_offset);
+
+int git_packfile_stream_open(git_packfile_stream *obj, struct git_pack_file *p, off64_t curpos);
+ssize_t git_packfile_stream_read(git_packfile_stream *obj, void *buffer, size_t len);
+void git_packfile_stream_dispose(git_packfile_stream *obj);
+
+int get_delta_base(
+ off64_t *delta_base_out,
+ struct git_pack_file *p,
+ git_mwindow **w_curs,
+ off64_t *curpos,
+ git_object_t type,
+ off64_t delta_obj_offset);
+
+void git_packfile_free(struct git_pack_file *p, bool unlink_packfile);
+int git_packfile_alloc(struct git_pack_file **pack_out, const char *path);
+
+int git_pack_entry_find(
+ struct git_pack_entry *e,
+ struct git_pack_file *p,
+ const git_oid *short_oid,
+ size_t len);
+int git_pack_foreach_entry(
+ struct git_pack_file *p,
+ git_odb_foreach_cb cb,
+ void *data);
+/**
+ * Similar to git_pack_foreach_entry, but:
+ * - It also provides the offset of the object within the
+ * packfile.
+ * - It does not sort the objects in any order.
+ * - It retains the lock while invoking the callback.
+ */
+int git_pack_foreach_entry_offset(
+ struct git_pack_file *p,
+ git_pack_foreach_entry_offset_cb cb,
+ void *data);
+
+#endif
projects / libgit2.git / blobdiff