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27 results

cache.h

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  • user avatar
    Junio C Hamano authored
    Apple's common crypto implementation of SHA1_Update() does not take
    more than 4GB at a time, and we now have a compile-time workaround
    for it.
    
    * ad/sha1-update-chunked:
      sha1: allow limiting the size of the data passed to SHA1_Update()
      sha1: provide another level of indirection for the SHA-1 functions
    b5d2d8ee
    History
    cache.h 60.43 KiB
    #ifndef CACHE_H
    #define CACHE_H
    
    #include "git-compat-util.h"
    #include "strbuf.h"
    #include "hashmap.h"
    #include "advice.h"
    #include "gettext.h"
    #include "convert.h"
    #include "trace.h"
    #include "string-list.h"
    
    #include SHA1_HEADER
    #ifndef platform_SHA_CTX
    /*
     * platform's underlying implementation of SHA-1; could be OpenSSL,
     * blk_SHA, Apple CommonCrypto, etc...  Note that including
     * SHA1_HEADER may have already defined platform_SHA_CTX for our
     * own implementations like block-sha1 and ppc-sha1, so we list
     * the default for OpenSSL compatible SHA-1 implementations here.
     */
    #define platform_SHA_CTX	SHA_CTX
    #define platform_SHA1_Init	SHA1_Init
    #define platform_SHA1_Update	SHA1_Update
    #define platform_SHA1_Final    	SHA1_Final
    #endif
    
    #define git_SHA_CTX		platform_SHA_CTX
    #define git_SHA1_Init		platform_SHA1_Init
    #define git_SHA1_Update		platform_SHA1_Update
    #define git_SHA1_Final		platform_SHA1_Final
    
    #ifdef SHA1_MAX_BLOCK_SIZE
    #include "compat/sha1-chunked.h"
    #undef git_SHA1_Update
    #define git_SHA1_Update		git_SHA1_Update_Chunked
    #endif
    
    #include <zlib.h>
    typedef struct git_zstream {
    	z_stream z;
    	unsigned long avail_in;
    	unsigned long avail_out;
    	unsigned long total_in;
    	unsigned long total_out;
    	unsigned char *next_in;
    	unsigned char *next_out;
    } git_zstream;
    
    void git_inflate_init(git_zstream *);
    void git_inflate_init_gzip_only(git_zstream *);
    void git_inflate_end(git_zstream *);
    int git_inflate(git_zstream *, int flush);
    
    void git_deflate_init(git_zstream *, int level);
    void git_deflate_init_gzip(git_zstream *, int level);
    void git_deflate_init_raw(git_zstream *, int level);
    void git_deflate_end(git_zstream *);
    int git_deflate_abort(git_zstream *);
    int git_deflate_end_gently(git_zstream *);
    int git_deflate(git_zstream *, int flush);
    unsigned long git_deflate_bound(git_zstream *, unsigned long);
    
    /* The length in bytes and in hex digits of an object name (SHA-1 value). */
    #define GIT_SHA1_RAWSZ 20
    #define GIT_SHA1_HEXSZ (2 * GIT_SHA1_RAWSZ)
    
    struct object_id {
    	unsigned char hash[GIT_SHA1_RAWSZ];
    };
    
    #if defined(DT_UNKNOWN) && !defined(NO_D_TYPE_IN_DIRENT)
    #define DTYPE(de)	((de)->d_type)
    #else
    #undef DT_UNKNOWN
    #undef DT_DIR
    #undef DT_REG
    #undef DT_LNK
    #define DT_UNKNOWN	0
    #define DT_DIR		1
    #define DT_REG		2
    #define DT_LNK		3
    #define DTYPE(de)	DT_UNKNOWN
    #endif
    
    /* unknown mode (impossible combination S_IFIFO|S_IFCHR) */
    #define S_IFINVALID     0030000
    
    /*
     * A "directory link" is a link to another git directory.
     *
     * The value 0160000 is not normally a valid mode, and
     * also just happens to be S_IFDIR + S_IFLNK
     */
    #define S_IFGITLINK	0160000
    #define S_ISGITLINK(m)	(((m) & S_IFMT) == S_IFGITLINK)
    
    /*
     * Some mode bits are also used internally for computations.
     *
     * They *must* not overlap with any valid modes, and they *must* not be emitted
     * to outside world - i.e. appear on disk or network. In other words, it's just
     * temporary fields, which we internally use, but they have to stay in-house.
     *
     * ( such approach is valid, as standard S_IF* fits into 16 bits, and in Git
     *   codebase mode is `unsigned int` which is assumed to be at least 32 bits )
     */
    
    /* used internally in tree-diff */
    #define S_DIFFTREE_IFXMIN_NEQ	0x80000000
    
    
    /*
     * Intensive research over the course of many years has shown that
     * port 9418 is totally unused by anything else. Or
     *
     *	Your search - "port 9418" - did not match any documents.
     *
     * as www.google.com puts it.
     *
     * This port has been properly assigned for git use by IANA:
     * git (Assigned-9418) [I06-050728-0001].
     *
     *	git  9418/tcp   git pack transfer service
     *	git  9418/udp   git pack transfer service
     *
     * with Linus Torvalds <torvalds@osdl.org> as the point of
     * contact. September 2005.
     *
     * See http://www.iana.org/assignments/port-numbers
     */
    #define DEFAULT_GIT_PORT 9418
    
    /*
     * Basic data structures for the directory cache
     */
    
    #define CACHE_SIGNATURE 0x44495243	/* "DIRC" */
    struct cache_header {
    	uint32_t hdr_signature;
    	uint32_t hdr_version;
    	uint32_t hdr_entries;
    };
    
    #define INDEX_FORMAT_LB 2
    #define INDEX_FORMAT_UB 4
    
    /*
     * The "cache_time" is just the low 32 bits of the
     * time. It doesn't matter if it overflows - we only
     * check it for equality in the 32 bits we save.
     */
    struct cache_time {
    	uint32_t sec;
    	uint32_t nsec;
    };
    
    struct stat_data {
    	struct cache_time sd_ctime;
    	struct cache_time sd_mtime;
    	unsigned int sd_dev;
    	unsigned int sd_ino;
    	unsigned int sd_uid;
    	unsigned int sd_gid;
    	unsigned int sd_size;
    };
    
    struct cache_entry {
    	struct hashmap_entry ent;
    	struct stat_data ce_stat_data;
    	unsigned int ce_mode;
    	unsigned int ce_flags;
    	unsigned int ce_namelen;
    	unsigned int index;	/* for link extension */
    	unsigned char sha1[20];
    	char name[FLEX_ARRAY]; /* more */
    };
    
    #define CE_STAGEMASK (0x3000)
    #define CE_EXTENDED  (0x4000)
    #define CE_VALID     (0x8000)
    #define CE_STAGESHIFT 12
    
    /*
     * Range 0xFFFF0FFF in ce_flags is divided into
     * two parts: in-memory flags and on-disk ones.
     * Flags in CE_EXTENDED_FLAGS will get saved on-disk
     * if you want to save a new flag, add it in
     * CE_EXTENDED_FLAGS
     *
     * In-memory only flags
     */
    #define CE_UPDATE            (1 << 16)
    #define CE_REMOVE            (1 << 17)
    #define CE_UPTODATE          (1 << 18)
    #define CE_ADDED             (1 << 19)
    
    #define CE_HASHED            (1 << 20)
    #define CE_WT_REMOVE         (1 << 22) /* remove in work directory */
    #define CE_CONFLICTED        (1 << 23)
    
    #define CE_UNPACKED          (1 << 24)
    #define CE_NEW_SKIP_WORKTREE (1 << 25)
    
    /* used to temporarily mark paths matched by pathspecs */
    #define CE_MATCHED           (1 << 26)
    
    #define CE_UPDATE_IN_BASE    (1 << 27)
    #define CE_STRIP_NAME        (1 << 28)
    
    /*
     * Extended on-disk flags
     */
    #define CE_INTENT_TO_ADD     (1 << 29)
    #define CE_SKIP_WORKTREE     (1 << 30)
    /* CE_EXTENDED2 is for future extension */
    #define CE_EXTENDED2         (1 << 31)
    
    #define CE_EXTENDED_FLAGS (CE_INTENT_TO_ADD | CE_SKIP_WORKTREE)
    
    /*
     * Safeguard to avoid saving wrong flags:
     *  - CE_EXTENDED2 won't get saved until its semantic is known
     *  - Bits in 0x0000FFFF have been saved in ce_flags already
     *  - Bits in 0x003F0000 are currently in-memory flags
     */
    #if CE_EXTENDED_FLAGS & 0x803FFFFF
    #error "CE_EXTENDED_FLAGS out of range"
    #endif
    
    struct pathspec;
    
    /*
     * Copy the sha1 and stat state of a cache entry from one to
     * another. But we never change the name, or the hash state!
     */
    static inline void copy_cache_entry(struct cache_entry *dst,
    				    const struct cache_entry *src)
    {
    	unsigned int state = dst->ce_flags & CE_HASHED;
    
    	/* Don't copy hash chain and name */
    	memcpy(&dst->ce_stat_data, &src->ce_stat_data,
    			offsetof(struct cache_entry, name) -
    			offsetof(struct cache_entry, ce_stat_data));
    
    	/* Restore the hash state */
    	dst->ce_flags = (dst->ce_flags & ~CE_HASHED) | state;
    }
    
    static inline unsigned create_ce_flags(unsigned stage)
    {
    	return (stage << CE_STAGESHIFT);
    }
    
    #define ce_namelen(ce) ((ce)->ce_namelen)
    #define ce_size(ce) cache_entry_size(ce_namelen(ce))
    #define ce_stage(ce) ((CE_STAGEMASK & (ce)->ce_flags) >> CE_STAGESHIFT)
    #define ce_uptodate(ce) ((ce)->ce_flags & CE_UPTODATE)
    #define ce_skip_worktree(ce) ((ce)->ce_flags & CE_SKIP_WORKTREE)
    #define ce_mark_uptodate(ce) ((ce)->ce_flags |= CE_UPTODATE)
    
    #define ce_permissions(mode) (((mode) & 0100) ? 0755 : 0644)
    static inline unsigned int create_ce_mode(unsigned int mode)
    {
    	if (S_ISLNK(mode))
    		return S_IFLNK;
    	if (S_ISDIR(mode) || S_ISGITLINK(mode))
    		return S_IFGITLINK;
    	return S_IFREG | ce_permissions(mode);
    }
    static inline unsigned int ce_mode_from_stat(const struct cache_entry *ce,
    					     unsigned int mode)
    {
    	extern int trust_executable_bit, has_symlinks;
    	if (!has_symlinks && S_ISREG(mode) &&
    	    ce && S_ISLNK(ce->ce_mode))
    		return ce->ce_mode;
    	if (!trust_executable_bit && S_ISREG(mode)) {
    		if (ce && S_ISREG(ce->ce_mode))
    			return ce->ce_mode;
    		return create_ce_mode(0666);
    	}
    	return create_ce_mode(mode);
    }
    static inline int ce_to_dtype(const struct cache_entry *ce)
    {
    	unsigned ce_mode = ntohl(ce->ce_mode);
    	if (S_ISREG(ce_mode))
    		return DT_REG;
    	else if (S_ISDIR(ce_mode) || S_ISGITLINK(ce_mode))
    		return DT_DIR;
    	else if (S_ISLNK(ce_mode))
    		return DT_LNK;
    	else
    		return DT_UNKNOWN;
    }
    static inline unsigned int canon_mode(unsigned int mode)
    {
    	if (S_ISREG(mode))
    		return S_IFREG | ce_permissions(mode);
    	if (S_ISLNK(mode))
    		return S_IFLNK;
    	if (S_ISDIR(mode))
    		return S_IFDIR;
    	return S_IFGITLINK;
    }
    
    #define cache_entry_size(len) (offsetof(struct cache_entry,name) + (len) + 1)
    
    #define SOMETHING_CHANGED	(1 << 0) /* unclassified changes go here */
    #define CE_ENTRY_CHANGED	(1 << 1)
    #define CE_ENTRY_REMOVED	(1 << 2)
    #define CE_ENTRY_ADDED		(1 << 3)
    #define RESOLVE_UNDO_CHANGED	(1 << 4)
    #define CACHE_TREE_CHANGED	(1 << 5)
    #define SPLIT_INDEX_ORDERED	(1 << 6)
    #define UNTRACKED_CHANGED	(1 << 7)
    
    struct split_index;
    struct untracked_cache;
    
    struct index_state {
    	struct cache_entry **cache;
    	unsigned int version;
    	unsigned int cache_nr, cache_alloc, cache_changed;
    	struct string_list *resolve_undo;
    	struct cache_tree *cache_tree;
    	struct split_index *split_index;
    	struct cache_time timestamp;
    	unsigned name_hash_initialized : 1,
    		 initialized : 1;
    	struct hashmap name_hash;
    	struct hashmap dir_hash;
    	unsigned char sha1[20];
    	struct untracked_cache *untracked;
    };
    
    extern struct index_state the_index;
    
    /* Name hashing */
    extern void add_name_hash(struct index_state *istate, struct cache_entry *ce);
    extern void remove_name_hash(struct index_state *istate, struct cache_entry *ce);
    extern void free_name_hash(struct index_state *istate);
    
    
    #ifndef NO_THE_INDEX_COMPATIBILITY_MACROS
    #define active_cache (the_index.cache)
    #define active_nr (the_index.cache_nr)
    #define active_alloc (the_index.cache_alloc)
    #define active_cache_changed (the_index.cache_changed)
    #define active_cache_tree (the_index.cache_tree)
    
    #define read_cache() read_index(&the_index)
    #define read_cache_from(path) read_index_from(&the_index, (path))
    #define read_cache_preload(pathspec) read_index_preload(&the_index, (pathspec))
    #define is_cache_unborn() is_index_unborn(&the_index)
    #define read_cache_unmerged() read_index_unmerged(&the_index)
    #define discard_cache() discard_index(&the_index)
    #define unmerged_cache() unmerged_index(&the_index)
    #define cache_name_pos(name, namelen) index_name_pos(&the_index,(name),(namelen))
    #define add_cache_entry(ce, option) add_index_entry(&the_index, (ce), (option))
    #define rename_cache_entry_at(pos, new_name) rename_index_entry_at(&the_index, (pos), (new_name))
    #define remove_cache_entry_at(pos) remove_index_entry_at(&the_index, (pos))
    #define remove_file_from_cache(path) remove_file_from_index(&the_index, (path))
    #define add_to_cache(path, st, flags) add_to_index(&the_index, (path), (st), (flags))
    #define add_file_to_cache(path, flags) add_file_to_index(&the_index, (path), (flags))
    #define refresh_cache(flags) refresh_index(&the_index, (flags), NULL, NULL, NULL)
    #define ce_match_stat(ce, st, options) ie_match_stat(&the_index, (ce), (st), (options))
    #define ce_modified(ce, st, options) ie_modified(&the_index, (ce), (st), (options))
    #define cache_dir_exists(name, namelen) index_dir_exists(&the_index, (name), (namelen))
    #define cache_file_exists(name, namelen, igncase) index_file_exists(&the_index, (name), (namelen), (igncase))
    #define cache_name_is_other(name, namelen) index_name_is_other(&the_index, (name), (namelen))
    #define resolve_undo_clear() resolve_undo_clear_index(&the_index)
    #define unmerge_cache_entry_at(at) unmerge_index_entry_at(&the_index, at)
    #define unmerge_cache(pathspec) unmerge_index(&the_index, pathspec)
    #define read_blob_data_from_cache(path, sz) read_blob_data_from_index(&the_index, (path), (sz))
    #endif
    
    enum object_type {
    	OBJ_BAD = -1,
    	OBJ_NONE = 0,
    	OBJ_COMMIT = 1,
    	OBJ_TREE = 2,
    	OBJ_BLOB = 3,
    	OBJ_TAG = 4,
    	/* 5 for future expansion */
    	OBJ_OFS_DELTA = 6,
    	OBJ_REF_DELTA = 7,
    	OBJ_ANY,
    	OBJ_MAX
    };
    
    static inline enum object_type object_type(unsigned int mode)
    {
    	return S_ISDIR(mode) ? OBJ_TREE :
    		S_ISGITLINK(mode) ? OBJ_COMMIT :
    		OBJ_BLOB;
    }
    
    /* Double-check local_repo_env below if you add to this list. */
    #define GIT_DIR_ENVIRONMENT "GIT_DIR"
    #define GIT_COMMON_DIR_ENVIRONMENT "GIT_COMMON_DIR"
    #define GIT_NAMESPACE_ENVIRONMENT "GIT_NAMESPACE"
    #define GIT_WORK_TREE_ENVIRONMENT "GIT_WORK_TREE"
    #define GIT_PREFIX_ENVIRONMENT "GIT_PREFIX"
    #define DEFAULT_GIT_DIR_ENVIRONMENT ".git"
    #define DB_ENVIRONMENT "GIT_OBJECT_DIRECTORY"
    #define INDEX_ENVIRONMENT "GIT_INDEX_FILE"
    #define GRAFT_ENVIRONMENT "GIT_GRAFT_FILE"
    #define GIT_SHALLOW_FILE_ENVIRONMENT "GIT_SHALLOW_FILE"
    #define TEMPLATE_DIR_ENVIRONMENT "GIT_TEMPLATE_DIR"
    #define CONFIG_ENVIRONMENT "GIT_CONFIG"
    #define CONFIG_DATA_ENVIRONMENT "GIT_CONFIG_PARAMETERS"
    #define EXEC_PATH_ENVIRONMENT "GIT_EXEC_PATH"
    #define CEILING_DIRECTORIES_ENVIRONMENT "GIT_CEILING_DIRECTORIES"
    #define NO_REPLACE_OBJECTS_ENVIRONMENT "GIT_NO_REPLACE_OBJECTS"
    #define GIT_REPLACE_REF_BASE_ENVIRONMENT "GIT_REPLACE_REF_BASE"
    #define GITATTRIBUTES_FILE ".gitattributes"
    #define INFOATTRIBUTES_FILE "info/attributes"
    #define ATTRIBUTE_MACRO_PREFIX "[attr]"
    #define GIT_NOTES_REF_ENVIRONMENT "GIT_NOTES_REF"
    #define GIT_NOTES_DEFAULT_REF "refs/notes/commits"
    #define GIT_NOTES_DISPLAY_REF_ENVIRONMENT "GIT_NOTES_DISPLAY_REF"
    #define GIT_NOTES_REWRITE_REF_ENVIRONMENT "GIT_NOTES_REWRITE_REF"
    #define GIT_NOTES_REWRITE_MODE_ENVIRONMENT "GIT_NOTES_REWRITE_MODE"
    #define GIT_LITERAL_PATHSPECS_ENVIRONMENT "GIT_LITERAL_PATHSPECS"
    #define GIT_GLOB_PATHSPECS_ENVIRONMENT "GIT_GLOB_PATHSPECS"
    #define GIT_NOGLOB_PATHSPECS_ENVIRONMENT "GIT_NOGLOB_PATHSPECS"
    #define GIT_ICASE_PATHSPECS_ENVIRONMENT "GIT_ICASE_PATHSPECS"
    
    /*
     * This environment variable is expected to contain a boolean indicating
     * whether we should or should not treat:
     *
     *   GIT_DIR=foo.git git ...
     *
     * as if GIT_WORK_TREE=. was given. It's not expected that users will make use
     * of this, but we use it internally to communicate to sub-processes that we
     * are in a bare repo. If not set, defaults to true.
     */
    #define GIT_IMPLICIT_WORK_TREE_ENVIRONMENT "GIT_IMPLICIT_WORK_TREE"
    
    /*
     * Repository-local GIT_* environment variables; these will be cleared
     * when git spawns a sub-process that runs inside another repository.
     * The array is NULL-terminated, which makes it easy to pass in the "env"
     * parameter of a run-command invocation, or to do a simple walk.
     */
    extern const char * const local_repo_env[];
    
    extern int is_bare_repository_cfg;
    extern int is_bare_repository(void);
    extern int is_inside_git_dir(void);
    extern char *git_work_tree_cfg;
    extern int is_inside_work_tree(void);
    extern const char *get_git_dir(void);
    extern const char *get_git_common_dir(void);
    extern int is_git_directory(const char *path);
    extern char *get_object_directory(void);
    extern char *get_index_file(void);
    extern char *get_graft_file(void);
    extern int set_git_dir(const char *path);
    extern int get_common_dir_noenv(struct strbuf *sb, const char *gitdir);
    extern int get_common_dir(struct strbuf *sb, const char *gitdir);
    extern const char *get_git_namespace(void);
    extern const char *strip_namespace(const char *namespaced_ref);
    extern const char *get_git_work_tree(void);
    
    #define READ_GITFILE_ERR_STAT_FAILED 1
    #define READ_GITFILE_ERR_NOT_A_FILE 2
    #define READ_GITFILE_ERR_OPEN_FAILED 3
    #define READ_GITFILE_ERR_READ_FAILED 4
    #define READ_GITFILE_ERR_INVALID_FORMAT 5
    #define READ_GITFILE_ERR_NO_PATH 6
    #define READ_GITFILE_ERR_NOT_A_REPO 7
    #define READ_GITFILE_ERR_TOO_LARGE 8
    extern const char *read_gitfile_gently(const char *path, int *return_error_code);
    #define read_gitfile(path) read_gitfile_gently((path), NULL)
    extern const char *resolve_gitdir(const char *suspect);
    extern void set_git_work_tree(const char *tree);
    
    #define ALTERNATE_DB_ENVIRONMENT "GIT_ALTERNATE_OBJECT_DIRECTORIES"
    
    extern const char **get_pathspec(const char *prefix, const char **pathspec);
    extern void setup_work_tree(void);
    extern const char *setup_git_directory_gently(int *);
    extern const char *setup_git_directory(void);
    extern char *prefix_path(const char *prefix, int len, const char *path);
    extern char *prefix_path_gently(const char *prefix, int len, int *remaining, const char *path);
    extern const char *prefix_filename(const char *prefix, int len, const char *path);
    extern int check_filename(const char *prefix, const char *name);
    extern void verify_filename(const char *prefix,
    			    const char *name,
    			    int diagnose_misspelt_rev);
    extern void verify_non_filename(const char *prefix, const char *name);
    extern int path_inside_repo(const char *prefix, const char *path);
    
    #define INIT_DB_QUIET 0x0001
    
    extern int set_git_dir_init(const char *git_dir, const char *real_git_dir, int);
    extern int init_db(const char *template_dir, unsigned int flags);
    
    extern void sanitize_stdfds(void);
    extern int daemonize(void);
    
    #define alloc_nr(x) (((x)+16)*3/2)
    
    /*
     * Realloc the buffer pointed at by variable 'x' so that it can hold
     * at least 'nr' entries; the number of entries currently allocated
     * is 'alloc', using the standard growing factor alloc_nr() macro.
     *
     * DO NOT USE any expression with side-effect for 'x', 'nr', or 'alloc'.
     */
    #define ALLOC_GROW(x, nr, alloc) \
    	do { \
    		if ((nr) > alloc) { \
    			if (alloc_nr(alloc) < (nr)) \
    				alloc = (nr); \
    			else \
    				alloc = alloc_nr(alloc); \
    			REALLOC_ARRAY(x, alloc); \
    		} \
    	} while (0)
    
    /* Initialize and use the cache information */
    struct lock_file;
    extern int read_index(struct index_state *);
    extern int read_index_preload(struct index_state *, const struct pathspec *pathspec);
    extern int do_read_index(struct index_state *istate, const char *path,
    			 int must_exist); /* for testting only! */
    extern int read_index_from(struct index_state *, const char *path);
    extern int is_index_unborn(struct index_state *);
    extern int read_index_unmerged(struct index_state *);
    #define COMMIT_LOCK		(1 << 0)
    #define CLOSE_LOCK		(1 << 1)
    extern int write_locked_index(struct index_state *, struct lock_file *lock, unsigned flags);
    extern int discard_index(struct index_state *);
    extern int unmerged_index(const struct index_state *);
    extern int verify_path(const char *path);
    extern int index_dir_exists(struct index_state *istate, const char *name, int namelen);
    extern void adjust_dirname_case(struct index_state *istate, char *name);
    extern struct cache_entry *index_file_exists(struct index_state *istate, const char *name, int namelen, int igncase);
    extern int index_name_pos(const struct index_state *, const char *name, int namelen);
    #define ADD_CACHE_OK_TO_ADD 1		/* Ok to add */
    #define ADD_CACHE_OK_TO_REPLACE 2	/* Ok to replace file/directory */
    #define ADD_CACHE_SKIP_DFCHECK 4	/* Ok to skip DF conflict checks */
    #define ADD_CACHE_JUST_APPEND 8		/* Append only; tree.c::read_tree() */
    #define ADD_CACHE_NEW_ONLY 16		/* Do not replace existing ones */
    #define ADD_CACHE_KEEP_CACHE_TREE 32	/* Do not invalidate cache-tree */
    extern int add_index_entry(struct index_state *, struct cache_entry *ce, int option);
    extern void rename_index_entry_at(struct index_state *, int pos, const char *new_name);
    extern int remove_index_entry_at(struct index_state *, int pos);
    extern void remove_marked_cache_entries(struct index_state *istate);
    extern int remove_file_from_index(struct index_state *, const char *path);
    #define ADD_CACHE_VERBOSE 1
    #define ADD_CACHE_PRETEND 2
    #define ADD_CACHE_IGNORE_ERRORS	4
    #define ADD_CACHE_IGNORE_REMOVAL 8
    #define ADD_CACHE_INTENT 16
    extern int add_to_index(struct index_state *, const char *path, struct stat *, int flags);
    extern int add_file_to_index(struct index_state *, const char *path, int flags);
    extern struct cache_entry *make_cache_entry(unsigned int mode, const unsigned char *sha1, const char *path, int stage, unsigned int refresh_options);
    extern int ce_same_name(const struct cache_entry *a, const struct cache_entry *b);
    extern void set_object_name_for_intent_to_add_entry(struct cache_entry *ce);
    extern int index_name_is_other(const struct index_state *, const char *, int);
    extern void *read_blob_data_from_index(struct index_state *, const char *, unsigned long *);
    
    /* do stat comparison even if CE_VALID is true */
    #define CE_MATCH_IGNORE_VALID		01
    /* do not check the contents but report dirty on racily-clean entries */
    #define CE_MATCH_RACY_IS_DIRTY		02
    /* do stat comparison even if CE_SKIP_WORKTREE is true */
    #define CE_MATCH_IGNORE_SKIP_WORKTREE	04
    /* ignore non-existent files during stat update  */
    #define CE_MATCH_IGNORE_MISSING		0x08
    /* enable stat refresh */
    #define CE_MATCH_REFRESH		0x10
    extern int ie_match_stat(const struct index_state *, const struct cache_entry *, struct stat *, unsigned int);
    extern int ie_modified(const struct index_state *, const struct cache_entry *, struct stat *, unsigned int);
    
    #define HASH_WRITE_OBJECT 1
    #define HASH_FORMAT_CHECK 2
    extern int index_fd(unsigned char *sha1, int fd, struct stat *st, enum object_type type, const char *path, unsigned flags);
    extern int index_path(unsigned char *sha1, const char *path, struct stat *st, unsigned flags);
    
    /*
     * Record to sd the data from st that we use to check whether a file
     * might have changed.
     */
    extern void fill_stat_data(struct stat_data *sd, struct stat *st);
    
    /*
     * Return 0 if st is consistent with a file not having been changed
     * since sd was filled.  If there are differences, return a
     * combination of MTIME_CHANGED, CTIME_CHANGED, OWNER_CHANGED,
     * INODE_CHANGED, and DATA_CHANGED.
     */
    extern int match_stat_data(const struct stat_data *sd, struct stat *st);
    extern int match_stat_data_racy(const struct index_state *istate,
    				const struct stat_data *sd, struct stat *st);
    
    extern void fill_stat_cache_info(struct cache_entry *ce, struct stat *st);
    
    #define REFRESH_REALLY		0x0001	/* ignore_valid */
    #define REFRESH_UNMERGED	0x0002	/* allow unmerged */
    #define REFRESH_QUIET		0x0004	/* be quiet about it */
    #define REFRESH_IGNORE_MISSING	0x0008	/* ignore non-existent */
    #define REFRESH_IGNORE_SUBMODULES	0x0010	/* ignore submodules */
    #define REFRESH_IN_PORCELAIN	0x0020	/* user friendly output, not "needs update" */
    extern int refresh_index(struct index_state *, unsigned int flags, const struct pathspec *pathspec, char *seen, const char *header_msg);
    
    extern void update_index_if_able(struct index_state *, struct lock_file *);
    
    extern int hold_locked_index(struct lock_file *, int);
    extern void set_alternate_index_output(const char *);
    
    /* Environment bits from configuration mechanism */
    extern int trust_executable_bit;
    extern int trust_ctime;
    extern int check_stat;
    extern int quote_path_fully;
    extern int has_symlinks;
    extern int minimum_abbrev, default_abbrev;
    extern int ignore_case;
    extern int assume_unchanged;
    extern int prefer_symlink_refs;
    extern int log_all_ref_updates;
    extern int warn_ambiguous_refs;
    extern int warn_on_object_refname_ambiguity;
    extern int shared_repository;
    extern const char *apply_default_whitespace;
    extern const char *apply_default_ignorewhitespace;
    extern const char *git_attributes_file;
    extern int zlib_compression_level;
    extern int core_compression_level;
    extern int core_compression_seen;
    extern size_t packed_git_window_size;
    extern size_t packed_git_limit;
    extern size_t delta_base_cache_limit;
    extern unsigned long big_file_threshold;
    extern unsigned long pack_size_limit_cfg;
    
    /*
     * Do replace refs need to be checked this run?  This variable is
     * initialized to true unless --no-replace-object is used or
     * $GIT_NO_REPLACE_OBJECTS is set, but is set to false by some
     * commands that do not want replace references to be active.  As an
     * optimization it is also set to false if replace references have
     * been sought but there were none.
     */
    extern int check_replace_refs;
    extern char *git_replace_ref_base;
    
    extern int fsync_object_files;
    extern int core_preload_index;
    extern int core_apply_sparse_checkout;
    extern int precomposed_unicode;
    extern int protect_hfs;
    extern int protect_ntfs;
    extern int git_db_env, git_index_env, git_graft_env, git_common_dir_env;
    
    /*
     * Include broken refs in all ref iterations, which will
     * generally choke dangerous operations rather than letting
     * them silently proceed without taking the broken ref into
     * account.
     */
    extern int ref_paranoia;
    
    /*
     * The character that begins a commented line in user-editable file
     * that is subject to stripspace.
     */
    extern char comment_line_char;
    extern int auto_comment_line_char;
    
    enum branch_track {
    	BRANCH_TRACK_UNSPECIFIED = -1,
    	BRANCH_TRACK_NEVER = 0,
    	BRANCH_TRACK_REMOTE,
    	BRANCH_TRACK_ALWAYS,
    	BRANCH_TRACK_EXPLICIT,
    	BRANCH_TRACK_OVERRIDE
    };
    
    enum rebase_setup_type {
    	AUTOREBASE_NEVER = 0,
    	AUTOREBASE_LOCAL,
    	AUTOREBASE_REMOTE,
    	AUTOREBASE_ALWAYS
    };
    
    enum push_default_type {
    	PUSH_DEFAULT_NOTHING = 0,
    	PUSH_DEFAULT_MATCHING,
    	PUSH_DEFAULT_SIMPLE,
    	PUSH_DEFAULT_UPSTREAM,
    	PUSH_DEFAULT_CURRENT,
    	PUSH_DEFAULT_UNSPECIFIED
    };
    
    extern enum branch_track git_branch_track;
    extern enum rebase_setup_type autorebase;
    extern enum push_default_type push_default;
    
    enum object_creation_mode {
    	OBJECT_CREATION_USES_HARDLINKS = 0,
    	OBJECT_CREATION_USES_RENAMES = 1
    };
    
    extern enum object_creation_mode object_creation_mode;
    
    extern char *notes_ref_name;
    
    extern int grafts_replace_parents;
    
    /*
     * GIT_REPO_VERSION is the version we write by default. The
     * _READ variant is the highest number we know how to
     * handle.
     */
    #define GIT_REPO_VERSION 0
    #define GIT_REPO_VERSION_READ 1
    extern int repository_format_version;
    extern int repository_format_precious_objects;
    extern int check_repository_format(void);
    
    #define MTIME_CHANGED	0x0001
    #define CTIME_CHANGED	0x0002
    #define OWNER_CHANGED	0x0004
    #define MODE_CHANGED    0x0008
    #define INODE_CHANGED   0x0010
    #define DATA_CHANGED    0x0020
    #define TYPE_CHANGED    0x0040
    
    /*
     * Return a statically allocated filename, either generically (mkpath), in
     * the repository directory (git_path), or in a submodule's repository
     * directory (git_path_submodule). In all cases, note that the result
     * may be overwritten by another call to _any_ of the functions. Consider
     * using the safer "dup" or "strbuf" formats below (in some cases, the
     * unsafe versions have already been removed).
     */
    extern const char *mkpath(const char *fmt, ...) __attribute__((format (printf, 1, 2)));
    extern const char *git_path(const char *fmt, ...) __attribute__((format (printf, 1, 2)));
    
    extern char *mksnpath(char *buf, size_t n, const char *fmt, ...)
    	__attribute__((format (printf, 3, 4)));
    extern void strbuf_git_path(struct strbuf *sb, const char *fmt, ...)
    	__attribute__((format (printf, 2, 3)));
    extern void strbuf_git_path_submodule(struct strbuf *sb, const char *path,
    				      const char *fmt, ...)
    	__attribute__((format (printf, 3, 4)));
    extern char *git_pathdup(const char *fmt, ...)
    	__attribute__((format (printf, 1, 2)));
    extern char *mkpathdup(const char *fmt, ...)
    	__attribute__((format (printf, 1, 2)));
    extern char *git_pathdup_submodule(const char *path, const char *fmt, ...)
    	__attribute__((format (printf, 2, 3)));
    
    extern void report_linked_checkout_garbage(void);
    
    /*
     * You can define a static memoized git path like:
     *
     *    static GIT_PATH_FUNC(git_path_foo, "FOO");
     *
     * or use one of the global ones below.
     */
    #define GIT_PATH_FUNC(func, filename) \
    	const char *func(void) \
    	{ \
    		static char *ret; \
    		if (!ret) \
    			ret = git_pathdup(filename); \
    		return ret; \
    	}
    
    const char *git_path_cherry_pick_head(void);
    const char *git_path_revert_head(void);
    const char *git_path_squash_msg(void);
    const char *git_path_merge_msg(void);
    const char *git_path_merge_rr(void);
    const char *git_path_merge_mode(void);
    const char *git_path_merge_head(void);
    const char *git_path_fetch_head(void);
    const char *git_path_shallow(void);
    
    /*
     * Return the name of the file in the local object database that would
     * be used to store a loose object with the specified sha1.  The
     * return value is a pointer to a statically allocated buffer that is
     * overwritten each time the function is called.
     */
    extern const char *sha1_file_name(const unsigned char *sha1);
    
    /*
     * Return the name of the (local) packfile with the specified sha1 in
     * its name.  The return value is a pointer to memory that is
     * overwritten each time this function is called.
     */
    extern char *sha1_pack_name(const unsigned char *sha1);
    
    /*
     * Return the name of the (local) pack index file with the specified
     * sha1 in its name.  The return value is a pointer to memory that is
     * overwritten each time this function is called.
     */
    extern char *sha1_pack_index_name(const unsigned char *sha1);
    
    extern const char *find_unique_abbrev(const unsigned char *sha1, int);
    extern const unsigned char null_sha1[GIT_SHA1_RAWSZ];
    
    static inline int hashcmp(const unsigned char *sha1, const unsigned char *sha2)
    {
    	int i;
    
    	for (i = 0; i < GIT_SHA1_RAWSZ; i++, sha1++, sha2++) {
    		if (*sha1 != *sha2)
    			return *sha1 - *sha2;
    	}
    
    	return 0;
    }
    
    static inline int oidcmp(const struct object_id *oid1, const struct object_id *oid2)
    {
    	return hashcmp(oid1->hash, oid2->hash);
    }
    
    static inline int is_null_sha1(const unsigned char *sha1)
    {
    	return !hashcmp(sha1, null_sha1);
    }
    
    static inline int is_null_oid(const struct object_id *oid)
    {
    	return !hashcmp(oid->hash, null_sha1);
    }
    
    static inline void hashcpy(unsigned char *sha_dst, const unsigned char *sha_src)
    {
    	memcpy(sha_dst, sha_src, GIT_SHA1_RAWSZ);
    }
    
    static inline void oidcpy(struct object_id *dst, const struct object_id *src)
    {
    	hashcpy(dst->hash, src->hash);
    }
    
    static inline void hashclr(unsigned char *hash)
    {
    	memset(hash, 0, GIT_SHA1_RAWSZ);
    }
    
    static inline void oidclr(struct object_id *oid)
    {
    	hashclr(oid->hash);
    }
    
    
    #define EMPTY_TREE_SHA1_HEX \
    	"4b825dc642cb6eb9a060e54bf8d69288fbee4904"
    #define EMPTY_TREE_SHA1_BIN_LITERAL \
    	 "\x4b\x82\x5d\xc6\x42\xcb\x6e\xb9\xa0\x60" \
    	 "\xe5\x4b\xf8\xd6\x92\x88\xfb\xee\x49\x04"
    #define EMPTY_TREE_SHA1_BIN \
    	 ((const unsigned char *) EMPTY_TREE_SHA1_BIN_LITERAL)
    
    #define EMPTY_BLOB_SHA1_HEX \
    	"e69de29bb2d1d6434b8b29ae775ad8c2e48c5391"
    #define EMPTY_BLOB_SHA1_BIN_LITERAL \
    	"\xe6\x9d\xe2\x9b\xb2\xd1\xd6\x43\x4b\x8b" \
    	"\x29\xae\x77\x5a\xd8\xc2\xe4\x8c\x53\x91"
    #define EMPTY_BLOB_SHA1_BIN \
    	((const unsigned char *) EMPTY_BLOB_SHA1_BIN_LITERAL)
    
    static inline int is_empty_blob_sha1(const unsigned char *sha1)
    {
    	return !hashcmp(sha1, EMPTY_BLOB_SHA1_BIN);
    }
    
    int git_mkstemp(char *path, size_t n, const char *template);
    
    int git_mkstemps(char *path, size_t n, const char *template, int suffix_len);
    
    /* set default permissions by passing mode arguments to open(2) */
    int git_mkstemps_mode(char *pattern, int suffix_len, int mode);
    int git_mkstemp_mode(char *pattern, int mode);
    
    /*
     * NOTE NOTE NOTE!!
     *
     * PERM_UMASK, OLD_PERM_GROUP and OLD_PERM_EVERYBODY enumerations must
     * not be changed. Old repositories have core.sharedrepository written in
     * numeric format, and therefore these values are preserved for compatibility
     * reasons.
     */
    enum sharedrepo {
    	PERM_UMASK          = 0,
    	OLD_PERM_GROUP      = 1,
    	OLD_PERM_EVERYBODY  = 2,
    	PERM_GROUP          = 0660,
    	PERM_EVERYBODY      = 0664
    };
    int git_config_perm(const char *var, const char *value);
    int adjust_shared_perm(const char *path);
    
    /*
     * Create the directory containing the named path, using care to be
     * somewhat safe against races.  Return one of the scld_error values
     * to indicate success/failure.
     *
     * SCLD_VANISHED indicates that one of the ancestor directories of the
     * path existed at one point during the function call and then
     * suddenly vanished, probably because another process pruned the
     * directory while we were working.  To be robust against this kind of
     * race, callers might want to try invoking the function again when it
     * returns SCLD_VANISHED.
     */
    enum scld_error {
    	SCLD_OK = 0,
    	SCLD_FAILED = -1,
    	SCLD_PERMS = -2,
    	SCLD_EXISTS = -3,
    	SCLD_VANISHED = -4
    };
    enum scld_error safe_create_leading_directories(char *path);
    enum scld_error safe_create_leading_directories_const(const char *path);
    
    int mkdir_in_gitdir(const char *path);
    extern char *expand_user_path(const char *path);
    const char *enter_repo(const char *path, int strict);
    static inline int is_absolute_path(const char *path)
    {
    	return is_dir_sep(path[0]) || has_dos_drive_prefix(path);
    }
    int is_directory(const char *);
    const char *real_path(const char *path);
    const char *real_path_if_valid(const char *path);
    const char *absolute_path(const char *path);
    const char *remove_leading_path(const char *in, const char *prefix);
    const char *relative_path(const char *in, const char *prefix, struct strbuf *sb);
    int normalize_path_copy_len(char *dst, const char *src, int *prefix_len);
    int normalize_path_copy(char *dst, const char *src);
    int longest_ancestor_length(const char *path, struct string_list *prefixes);
    char *strip_path_suffix(const char *path, const char *suffix);
    int daemon_avoid_alias(const char *path);
    extern int is_ntfs_dotgit(const char *name);
    
    /**
     * Return a newly allocated string with the evaluation of
     * "$XDG_CONFIG_HOME/git/$filename" if $XDG_CONFIG_HOME is non-empty, otherwise
     * "$HOME/.config/git/$filename". Return NULL upon error.
     */
    extern char *xdg_config_home(const char *filename);
    
    /* object replacement */
    #define LOOKUP_REPLACE_OBJECT 1
    #define LOOKUP_UNKNOWN_OBJECT 2
    extern void *read_sha1_file_extended(const unsigned char *sha1, enum object_type *type, unsigned long *size, unsigned flag);
    static inline void *read_sha1_file(const unsigned char *sha1, enum object_type *type, unsigned long *size)
    {
    	return read_sha1_file_extended(sha1, type, size, LOOKUP_REPLACE_OBJECT);
    }
    
    /*
     * This internal function is only declared here for the benefit of
     * lookup_replace_object().  Please do not call it directly.
     */
    extern const unsigned char *do_lookup_replace_object(const unsigned char *sha1);
    
    /*
     * If object sha1 should be replaced, return the replacement object's
     * name (replaced recursively, if necessary).  The return value is
     * either sha1 or a pointer to a permanently-allocated value.  When
     * object replacement is suppressed, always return sha1.
     */
    static inline const unsigned char *lookup_replace_object(const unsigned char *sha1)
    {
    	if (!check_replace_refs)
    		return sha1;
    	return do_lookup_replace_object(sha1);
    }
    
    static inline const unsigned char *lookup_replace_object_extended(const unsigned char *sha1, unsigned flag)
    {
    	if (!(flag & LOOKUP_REPLACE_OBJECT))
    		return sha1;
    	return lookup_replace_object(sha1);
    }
    
    /* Read and unpack a sha1 file into memory, write memory to a sha1 file */
    extern int sha1_object_info(const unsigned char *, unsigned long *);
    extern int hash_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1);
    extern int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *return_sha1);
    extern int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type, unsigned char *sha1, unsigned flags);
    extern int pretend_sha1_file(void *, unsigned long, enum object_type, unsigned char *);
    extern int force_object_loose(const unsigned char *sha1, time_t mtime);
    extern int git_open_noatime(const char *name);
    extern void *map_sha1_file(const unsigned char *sha1, unsigned long *size);
    extern int unpack_sha1_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz);
    extern int parse_sha1_header(const char *hdr, unsigned long *sizep);
    
    /* global flag to enable extra checks when accessing packed objects */
    extern int do_check_packed_object_crc;
    
    extern int check_sha1_signature(const unsigned char *sha1, void *buf, unsigned long size, const char *type);
    
    extern int finalize_object_file(const char *tmpfile, const char *filename);
    
    extern int has_sha1_pack(const unsigned char *sha1);
    
    /*
     * Return true iff we have an object named sha1, whether local or in
     * an alternate object database, and whether packed or loose.  This
     * function does not respect replace references.
     *
     * If the QUICK flag is set, do not re-check the pack directory
     * when we cannot find the object (this means we may give a false
     * negative answer if another process is simultaneously repacking).
     */
    #define HAS_SHA1_QUICK 0x1
    extern int has_sha1_file_with_flags(const unsigned char *sha1, int flags);
    static inline int has_sha1_file(const unsigned char *sha1)
    {
    	return has_sha1_file_with_flags(sha1, 0);
    }
    
    /*
     * Return true iff an alternate object database has a loose object
     * with the specified name.  This function does not respect replace
     * references.
     */
    extern int has_loose_object_nonlocal(const unsigned char *sha1);
    
    extern int has_pack_index(const unsigned char *sha1);
    
    extern void assert_sha1_type(const unsigned char *sha1, enum object_type expect);
    
    extern const signed char hexval_table[256];
    static inline unsigned int hexval(unsigned char c)
    {
    	return hexval_table[c];
    }
    
    /* Convert to/from hex/sha1 representation */
    #define MINIMUM_ABBREV minimum_abbrev
    #define DEFAULT_ABBREV default_abbrev
    
    struct object_context {
    	unsigned char tree[20];
    	char path[PATH_MAX];
    	unsigned mode;
    	/*
    	 * symlink_path is only used by get_tree_entry_follow_symlinks,
    	 * and only for symlinks that point outside the repository.
    	 */
    	struct strbuf symlink_path;
    };
    
    #define GET_SHA1_QUIETLY           01
    #define GET_SHA1_COMMIT            02
    #define GET_SHA1_COMMITTISH        04
    #define GET_SHA1_TREE             010
    #define GET_SHA1_TREEISH          020
    #define GET_SHA1_BLOB             040
    #define GET_SHA1_FOLLOW_SYMLINKS 0100
    #define GET_SHA1_ONLY_TO_DIE    04000
    
    extern int get_sha1(const char *str, unsigned char *sha1);
    extern int get_sha1_commit(const char *str, unsigned char *sha1);
    extern int get_sha1_committish(const char *str, unsigned char *sha1);
    extern int get_sha1_tree(const char *str, unsigned char *sha1);
    extern int get_sha1_treeish(const char *str, unsigned char *sha1);
    extern int get_sha1_blob(const char *str, unsigned char *sha1);
    extern void maybe_die_on_misspelt_object_name(const char *name, const char *prefix);
    extern int get_sha1_with_context(const char *str, unsigned flags, unsigned char *sha1, struct object_context *orc);
    
    typedef int each_abbrev_fn(const unsigned char *sha1, void *);
    extern int for_each_abbrev(const char *prefix, each_abbrev_fn, void *);
    
    /*
     * Try to read a SHA1 in hexadecimal format from the 40 characters
     * starting at hex.  Write the 20-byte result to sha1 in binary form.
     * Return 0 on success.  Reading stops if a NUL is encountered in the
     * input, so it is safe to pass this function an arbitrary
     * null-terminated string.
     */
    extern int get_sha1_hex(const char *hex, unsigned char *sha1);
    extern int get_oid_hex(const char *hex, struct object_id *sha1);
    
    extern char *sha1_to_hex(const unsigned char *sha1);	/* static buffer result! */
    extern char *oid_to_hex(const struct object_id *oid);	/* same static buffer as sha1_to_hex */
    
    extern int interpret_branch_name(const char *str, int len, struct strbuf *);
    extern int get_sha1_mb(const char *str, unsigned char *sha1);
    
    extern int validate_headref(const char *ref);
    
    extern int base_name_compare(const char *name1, int len1, int mode1, const char *name2, int len2, int mode2);
    extern int df_name_compare(const char *name1, int len1, int mode1, const char *name2, int len2, int mode2);
    extern int name_compare(const char *name1, size_t len1, const char *name2, size_t len2);
    extern int cache_name_stage_compare(const char *name1, int len1, int stage1, const char *name2, int len2, int stage2);
    
    extern void *read_object_with_reference(const unsigned char *sha1,
    					const char *required_type,
    					unsigned long *size,
    					unsigned char *sha1_ret);
    
    extern struct object *peel_to_type(const char *name, int namelen,
    				   struct object *o, enum object_type);
    
    struct date_mode {
    	enum date_mode_type {
    		DATE_NORMAL = 0,
    		DATE_RELATIVE,
    		DATE_SHORT,
    		DATE_LOCAL,
    		DATE_ISO8601,
    		DATE_ISO8601_STRICT,
    		DATE_RFC2822,
    		DATE_STRFTIME,
    		DATE_RAW
    	} type;
    	const char *strftime_fmt;
    };
    
    /*
     * Convenience helper for passing a constant type, like:
     *
     *   show_date(t, tz, DATE_MODE(NORMAL));
     */
    #define DATE_MODE(t) date_mode_from_type(DATE_##t)
    struct date_mode *date_mode_from_type(enum date_mode_type type);
    
    const char *show_date(unsigned long time, int timezone, const struct date_mode *mode);
    void show_date_relative(unsigned long time, int tz, const struct timeval *now,
    			struct strbuf *timebuf);
    int parse_date(const char *date, struct strbuf *out);
    int parse_date_basic(const char *date, unsigned long *timestamp, int *offset);
    int parse_expiry_date(const char *date, unsigned long *timestamp);
    void datestamp(struct strbuf *out);
    #define approxidate(s) approxidate_careful((s), NULL)
    unsigned long approxidate_careful(const char *, int *);
    unsigned long approxidate_relative(const char *date, const struct timeval *now);
    void parse_date_format(const char *format, struct date_mode *mode);
    int date_overflows(unsigned long date);
    
    #define IDENT_STRICT	       1
    #define IDENT_NO_DATE	       2
    #define IDENT_NO_NAME	       4
    extern const char *git_author_info(int);
    extern const char *git_committer_info(int);
    extern const char *fmt_ident(const char *name, const char *email, const char *date_str, int);
    extern const char *fmt_name(const char *name, const char *email);
    extern const char *ident_default_name(void);
    extern const char *ident_default_email(void);
    extern const char *git_editor(void);
    extern const char *git_pager(int stdout_is_tty);
    extern int git_ident_config(const char *, const char *, void *);
    
    struct ident_split {
    	const char *name_begin;
    	const char *name_end;
    	const char *mail_begin;
    	const char *mail_end;
    	const char *date_begin;
    	const char *date_end;
    	const char *tz_begin;
    	const char *tz_end;
    };
    /*
     * Signals an success with 0, but time part of the result may be NULL
     * if the input lacks timestamp and zone
     */
    extern int split_ident_line(struct ident_split *, const char *, int);
    
    /*
     * Like show_date, but pull the timestamp and tz parameters from
     * the ident_split. It will also sanity-check the values and produce
     * a well-known sentinel date if they appear bogus.
     */
    const char *show_ident_date(const struct ident_split *id,
    			    const struct date_mode *mode);
    
    /*
     * Compare split idents for equality or strict ordering. Note that we
     * compare only the ident part of the line, ignoring any timestamp.
     *
     * Because there are two fields, we must choose one as the primary key; we
     * currently arbitrarily pick the email.
     */
    extern int ident_cmp(const struct ident_split *, const struct ident_split *);
    
    struct checkout {
    	struct index_state *istate;
    	const char *base_dir;
    	int base_dir_len;
    	unsigned force:1,
    		 quiet:1,
    		 not_new:1,
    		 refresh_cache:1;
    };
    
    #define TEMPORARY_FILENAME_LENGTH 25
    extern int checkout_entry(struct cache_entry *ce, const struct checkout *state, char *topath);
    
    struct cache_def {
    	struct strbuf path;
    	int flags;
    	int track_flags;
    	int prefix_len_stat_func;
    };
    #define CACHE_DEF_INIT { STRBUF_INIT, 0, 0, 0 }
    static inline void cache_def_clear(struct cache_def *cache)
    {
    	strbuf_release(&cache->path);
    }
    
    extern int has_symlink_leading_path(const char *name, int len);
    extern int threaded_has_symlink_leading_path(struct cache_def *, const char *, int);
    extern int check_leading_path(const char *name, int len);
    extern int has_dirs_only_path(const char *name, int len, int prefix_len);
    extern void schedule_dir_for_removal(const char *name, int len);
    extern void remove_scheduled_dirs(void);
    
    extern struct alternate_object_database {
    	struct alternate_object_database *next;
    	char *name;
    	char base[FLEX_ARRAY]; /* more */
    } *alt_odb_list;
    extern void prepare_alt_odb(void);
    extern void read_info_alternates(const char * relative_base, int depth);
    extern void add_to_alternates_file(const char *reference);
    typedef int alt_odb_fn(struct alternate_object_database *, void *);
    extern int foreach_alt_odb(alt_odb_fn, void*);
    
    struct pack_window {
    	struct pack_window *next;
    	unsigned char *base;
    	off_t offset;
    	size_t len;
    	unsigned int last_used;
    	unsigned int inuse_cnt;
    };
    
    extern struct packed_git {
    	struct packed_git *next;
    	struct pack_window *windows;
    	off_t pack_size;
    	const void *index_data;
    	size_t index_size;
    	uint32_t num_objects;
    	uint32_t num_bad_objects;
    	unsigned char *bad_object_sha1;
    	int index_version;
    	time_t mtime;
    	int pack_fd;
    	unsigned pack_local:1,
    		 pack_keep:1,
    		 freshened:1,
    		 do_not_close:1;
    	unsigned char sha1[20];
    	/* something like ".git/objects/pack/xxxxx.pack" */
    	char pack_name[FLEX_ARRAY]; /* more */
    } *packed_git;
    
    struct pack_entry {
    	off_t offset;
    	unsigned char sha1[20];
    	struct packed_git *p;
    };
    
    extern struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path);
    
    /* A hook to report invalid files in pack directory */
    #define PACKDIR_FILE_PACK 1
    #define PACKDIR_FILE_IDX 2
    #define PACKDIR_FILE_GARBAGE 4
    extern void (*report_garbage)(unsigned seen_bits, const char *path);
    
    extern void prepare_packed_git(void);
    extern void reprepare_packed_git(void);
    extern void install_packed_git(struct packed_git *pack);
    
    extern struct packed_git *find_sha1_pack(const unsigned char *sha1,
    					 struct packed_git *packs);
    
    extern void pack_report(void);
    
    /*
     * mmap the index file for the specified packfile (if it is not
     * already mmapped).  Return 0 on success.
     */
    extern int open_pack_index(struct packed_git *);
    
    /*
     * munmap the index file for the specified packfile (if it is
     * currently mmapped).
     */
    extern void close_pack_index(struct packed_git *);
    
    extern unsigned char *use_pack(struct packed_git *, struct pack_window **, off_t, unsigned long *);
    extern void close_pack_windows(struct packed_git *);
    extern void close_all_packs(void);
    extern void unuse_pack(struct pack_window **);
    extern void free_pack_by_name(const char *);
    extern void clear_delta_base_cache(void);
    extern struct packed_git *add_packed_git(const char *, int, int);
    
    /*
     * Return the SHA-1 of the nth object within the specified packfile.
     * Open the index if it is not already open.  The return value points
     * at the SHA-1 within the mmapped index.  Return NULL if there is an
     * error.
     */
    extern const unsigned char *nth_packed_object_sha1(struct packed_git *, uint32_t n);
    
    /*
     * Return the offset of the nth object within the specified packfile.
     * The index must already be opened.
     */
    extern off_t nth_packed_object_offset(const struct packed_git *, uint32_t n);
    
    /*
     * If the object named sha1 is present in the specified packfile,
     * return its offset within the packfile; otherwise, return 0.
     */
    extern off_t find_pack_entry_one(const unsigned char *sha1, struct packed_git *);
    
    extern int is_pack_valid(struct packed_git *);
    extern void *unpack_entry(struct packed_git *, off_t, enum object_type *, unsigned long *);
    extern unsigned long unpack_object_header_buffer(const unsigned char *buf, unsigned long len, enum object_type *type, unsigned long *sizep);
    extern unsigned long get_size_from_delta(struct packed_git *, struct pack_window **, off_t);
    extern int unpack_object_header(struct packed_git *, struct pack_window **, off_t *, unsigned long *);
    
    /*
     * Iterate over the files in the loose-object parts of the object
     * directory "path", triggering the following callbacks:
     *
     *  - loose_object is called for each loose object we find.
     *
     *  - loose_cruft is called for any files that do not appear to be
     *    loose objects. Note that we only look in the loose object
     *    directories "objects/[0-9a-f]{2}/", so we will not report
     *    "objects/foobar" as cruft.
     *
     *  - loose_subdir is called for each top-level hashed subdirectory
     *    of the object directory (e.g., "$OBJDIR/f0"). It is called
     *    after the objects in the directory are processed.
     *
     * Any callback that is NULL will be ignored. Callbacks returning non-zero
     * will end the iteration.
     *
     * In the "buf" variant, "path" is a strbuf which will also be used as a
     * scratch buffer, but restored to its original contents before
     * the function returns.
     */
    typedef int each_loose_object_fn(const unsigned char *sha1,
    				 const char *path,
    				 void *data);
    typedef int each_loose_cruft_fn(const char *basename,
    				const char *path,
    				void *data);
    typedef int each_loose_subdir_fn(int nr,
    				 const char *path,
    				 void *data);
    int for_each_loose_file_in_objdir(const char *path,
    				  each_loose_object_fn obj_cb,
    				  each_loose_cruft_fn cruft_cb,
    				  each_loose_subdir_fn subdir_cb,
    				  void *data);
    int for_each_loose_file_in_objdir_buf(struct strbuf *path,
    				      each_loose_object_fn obj_cb,
    				      each_loose_cruft_fn cruft_cb,
    				      each_loose_subdir_fn subdir_cb,
    				      void *data);
    
    /*
     * Iterate over loose and packed objects in both the local
     * repository and any alternates repositories (unless the
     * LOCAL_ONLY flag is set).
     */
    #define FOR_EACH_OBJECT_LOCAL_ONLY 0x1
    typedef int each_packed_object_fn(const unsigned char *sha1,
    				  struct packed_git *pack,
    				  uint32_t pos,
    				  void *data);
    extern int for_each_loose_object(each_loose_object_fn, void *, unsigned flags);
    extern int for_each_packed_object(each_packed_object_fn, void *, unsigned flags);
    
    struct object_info {
    	/* Request */
    	enum object_type *typep;
    	unsigned long *sizep;
    	unsigned long *disk_sizep;
    	unsigned char *delta_base_sha1;
    	struct strbuf *typename;
    
    	/* Response */
    	enum {
    		OI_CACHED,
    		OI_LOOSE,
    		OI_PACKED,
    		OI_DBCACHED
    	} whence;
    	union {
    		/*
    		 * struct {
    		 * 	... Nothing to expose in this case
    		 * } cached;
    		 * struct {
    		 * 	... Nothing to expose in this case
    		 * } loose;
    		 */
    		struct {
    			struct packed_git *pack;
    			off_t offset;
    			unsigned int is_delta;
    		} packed;
    	} u;
    };
    extern int sha1_object_info_extended(const unsigned char *, struct object_info *, unsigned flags);
    
    /* Dumb servers support */
    extern int update_server_info(int);
    
    /* git_config_parse_key() returns these negated: */
    #define CONFIG_INVALID_KEY 1
    #define CONFIG_NO_SECTION_OR_NAME 2
    /* git_config_set(), git_config_set_multivar() return the above or these: */
    #define CONFIG_NO_LOCK -1
    #define CONFIG_INVALID_FILE 3
    #define CONFIG_NO_WRITE 4
    #define CONFIG_NOTHING_SET 5
    #define CONFIG_INVALID_PATTERN 6
    #define CONFIG_GENERIC_ERROR 7
    
    #define CONFIG_REGEX_NONE ((void *)1)
    
    struct git_config_source {
    	unsigned int use_stdin:1;
    	const char *file;
    	const char *blob;
    };
    
    typedef int (*config_fn_t)(const char *, const char *, void *);
    extern int git_default_config(const char *, const char *, void *);
    extern int git_config_from_file(config_fn_t fn, const char *, void *);
    extern int git_config_from_buf(config_fn_t fn, const char *name,
    			       const char *buf, size_t len, void *data);
    extern void git_config_push_parameter(const char *text);
    extern int git_config_from_parameters(config_fn_t fn, void *data);
    extern void git_config(config_fn_t fn, void *);
    extern int git_config_with_options(config_fn_t fn, void *,
    				   struct git_config_source *config_source,
    				   int respect_includes);
    extern int git_config_early(config_fn_t fn, void *, const char *repo_config);
    extern int git_parse_ulong(const char *, unsigned long *);
    extern int git_parse_maybe_bool(const char *);
    extern int git_config_int(const char *, const char *);
    extern int64_t git_config_int64(const char *, const char *);
    extern unsigned long git_config_ulong(const char *, const char *);
    extern int git_config_bool_or_int(const char *, const char *, int *);
    extern int git_config_bool(const char *, const char *);
    extern int git_config_maybe_bool(const char *, const char *);
    extern int git_config_string(const char **, const char *, const char *);
    extern int git_config_pathname(const char **, const char *, const char *);
    extern int git_config_set_in_file(const char *, const char *, const char *);
    extern int git_config_set(const char *, const char *);
    extern int git_config_parse_key(const char *, char **, int *);
    extern int git_config_key_is_valid(const char *key);
    extern int git_config_set_multivar(const char *, const char *, const char *, int);
    extern int git_config_set_multivar_in_file(const char *, const char *, const char *, const char *, int);
    extern int git_config_rename_section(const char *, const char *);
    extern int git_config_rename_section_in_file(const char *, const char *, const char *);
    extern const char *git_etc_gitconfig(void);
    extern int check_repository_format_version(const char *var, const char *value, void *cb);
    extern int git_env_bool(const char *, int);
    extern unsigned long git_env_ulong(const char *, unsigned long);
    extern int git_config_system(void);
    extern int config_error_nonbool(const char *);
    #if defined(__GNUC__)
    #define config_error_nonbool(s) (config_error_nonbool(s), const_error())
    #endif
    extern const char *get_log_output_encoding(void);
    extern const char *get_commit_output_encoding(void);
    
    extern int git_config_parse_parameter(const char *, config_fn_t fn, void *data);
    
    struct config_include_data {
    	int depth;
    	config_fn_t fn;
    	void *data;
    };
    #define CONFIG_INCLUDE_INIT { 0 }
    extern int git_config_include(const char *name, const char *value, void *data);
    
    /*
     * Match and parse a config key of the form:
     *
     *   section.(subsection.)?key
     *
     * (i.e., what gets handed to a config_fn_t). The caller provides the section;
     * we return -1 if it does not match, 0 otherwise. The subsection and key
     * out-parameters are filled by the function (and subsection is NULL if it is
     * missing).
     */
    extern int parse_config_key(const char *var,
    			    const char *section,
    			    const char **subsection, int *subsection_len,
    			    const char **key);
    
    struct config_set_element {
    	struct hashmap_entry ent;
    	char *key;
    	struct string_list value_list;
    };
    
    struct configset_list_item {
    	struct config_set_element *e;
    	int value_index;
    };
    
    /*
     * the contents of the list are ordered according to their
     * position in the config files and order of parsing the files.
     * (i.e. key-value pair at the last position of .git/config will
     * be at the last item of the list)
     */
    struct configset_list {
    	struct configset_list_item *items;
    	unsigned int nr, alloc;
    };
    
    struct config_set {
    	struct hashmap config_hash;
    	int hash_initialized;
    	struct configset_list list;
    };
    
    extern void git_configset_init(struct config_set *cs);
    extern int git_configset_add_file(struct config_set *cs, const char *filename);
    extern int git_configset_get_value(struct config_set *cs, const char *key, const char **value);
    extern const struct string_list *git_configset_get_value_multi(struct config_set *cs, const char *key);
    extern void git_configset_clear(struct config_set *cs);
    extern int git_configset_get_string_const(struct config_set *cs, const char *key, const char **dest);
    extern int git_configset_get_string(struct config_set *cs, const char *key, char **dest);
    extern int git_configset_get_int(struct config_set *cs, const char *key, int *dest);
    extern int git_configset_get_ulong(struct config_set *cs, const char *key, unsigned long *dest);
    extern int git_configset_get_bool(struct config_set *cs, const char *key, int *dest);
    extern int git_configset_get_bool_or_int(struct config_set *cs, const char *key, int *is_bool, int *dest);
    extern int git_configset_get_maybe_bool(struct config_set *cs, const char *key, int *dest);
    extern int git_configset_get_pathname(struct config_set *cs, const char *key, const char **dest);
    
    extern int git_config_get_value(const char *key, const char **value);
    extern const struct string_list *git_config_get_value_multi(const char *key);
    extern void git_config_clear(void);
    extern void git_config_iter(config_fn_t fn, void *data);
    extern int git_config_get_string_const(const char *key, const char **dest);
    extern int git_config_get_string(const char *key, char **dest);
    extern int git_config_get_int(const char *key, int *dest);
    extern int git_config_get_ulong(const char *key, unsigned long *dest);
    extern int git_config_get_bool(const char *key, int *dest);
    extern int git_config_get_bool_or_int(const char *key, int *is_bool, int *dest);
    extern int git_config_get_maybe_bool(const char *key, int *dest);
    extern int git_config_get_pathname(const char *key, const char **dest);
    
    struct key_value_info {
    	const char *filename;
    	int linenr;
    };
    
    extern NORETURN void git_die_config(const char *key, const char *err, ...) __attribute__((format(printf, 2, 3)));
    extern NORETURN void git_die_config_linenr(const char *key, const char *filename, int linenr);
    
    extern int committer_ident_sufficiently_given(void);
    extern int author_ident_sufficiently_given(void);
    
    extern const char *git_commit_encoding;
    extern const char *git_log_output_encoding;
    extern const char *git_mailmap_file;
    extern const char *git_mailmap_blob;
    
    /* IO helper functions */
    extern void maybe_flush_or_die(FILE *, const char *);
    __attribute__((format (printf, 2, 3)))
    extern void fprintf_or_die(FILE *, const char *fmt, ...);
    
    #define COPY_READ_ERROR (-2)
    #define COPY_WRITE_ERROR (-3)
    extern int copy_fd(int ifd, int ofd);
    extern int copy_file(const char *dst, const char *src, int mode);
    extern int copy_file_with_time(const char *dst, const char *src, int mode);
    
    extern void write_or_die(int fd, const void *buf, size_t count);
    extern int write_or_whine(int fd, const void *buf, size_t count, const char *msg);
    extern int write_or_whine_pipe(int fd, const void *buf, size_t count, const char *msg);
    extern void fsync_or_die(int fd, const char *);
    
    extern ssize_t read_in_full(int fd, void *buf, size_t count);
    extern ssize_t write_in_full(int fd, const void *buf, size_t count);
    extern ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset);
    
    static inline ssize_t write_str_in_full(int fd, const char *str)
    {
    	return write_in_full(fd, str, strlen(str));
    }
    
    extern int write_file(const char *path, const char *fmt, ...);
    extern int write_file_gently(const char *path, const char *fmt, ...);
    
    /* pager.c */
    extern void setup_pager(void);
    extern const char *pager_program;
    extern int pager_in_use(void);
    extern int pager_use_color;
    extern int term_columns(void);
    extern int decimal_width(uintmax_t);
    extern int check_pager_config(const char *cmd);
    
    extern const char *editor_program;
    extern const char *askpass_program;
    extern const char *excludes_file;
    
    /* base85 */
    int decode_85(char *dst, const char *line, int linelen);
    void encode_85(char *buf, const unsigned char *data, int bytes);
    
    /* alloc.c */
    extern void *alloc_blob_node(void);
    extern void *alloc_tree_node(void);
    extern void *alloc_commit_node(void);
    extern void *alloc_tag_node(void);
    extern void *alloc_object_node(void);
    extern void alloc_report(void);
    extern unsigned int alloc_commit_index(void);
    
    /* pkt-line.c */
    void packet_trace_identity(const char *prog);
    
    /* add */
    /*
     * return 0 if success, 1 - if addition of a file failed and
     * ADD_FILES_IGNORE_ERRORS was specified in flags
     */
    int add_files_to_cache(const char *prefix, const struct pathspec *pathspec, int flags);
    
    /* diff.c */
    extern int diff_auto_refresh_index;
    
    /* match-trees.c */
    void shift_tree(const unsigned char *, const unsigned char *, unsigned char *, int);
    void shift_tree_by(const unsigned char *, const unsigned char *, unsigned char *, const char *);
    
    /*
     * whitespace rules.
     * used by both diff and apply
     * last two digits are tab width
     */
    #define WS_BLANK_AT_EOL         0100
    #define WS_SPACE_BEFORE_TAB     0200
    #define WS_INDENT_WITH_NON_TAB  0400
    #define WS_CR_AT_EOL           01000
    #define WS_BLANK_AT_EOF        02000
    #define WS_TAB_IN_INDENT       04000
    #define WS_TRAILING_SPACE      (WS_BLANK_AT_EOL|WS_BLANK_AT_EOF)
    #define WS_DEFAULT_RULE (WS_TRAILING_SPACE|WS_SPACE_BEFORE_TAB|8)
    #define WS_TAB_WIDTH_MASK        077
    extern unsigned whitespace_rule_cfg;
    extern unsigned whitespace_rule(const char *);
    extern unsigned parse_whitespace_rule(const char *);
    extern unsigned ws_check(const char *line, int len, unsigned ws_rule);
    extern void ws_check_emit(const char *line, int len, unsigned ws_rule, FILE *stream, const char *set, const char *reset, const char *ws);
    extern char *whitespace_error_string(unsigned ws);
    extern void ws_fix_copy(struct strbuf *, const char *, int, unsigned, int *);
    extern int ws_blank_line(const char *line, int len, unsigned ws_rule);
    #define ws_tab_width(rule)     ((rule) & WS_TAB_WIDTH_MASK)
    
    /* ls-files */
    void overlay_tree_on_cache(const char *tree_name, const char *prefix);
    
    char *alias_lookup(const char *alias);
    int split_cmdline(char *cmdline, const char ***argv);
    /* Takes a negative value returned by split_cmdline */
    const char *split_cmdline_strerror(int cmdline_errno);
    
    /* git.c */
    struct startup_info {
    	int have_repository;
    	const char *prefix;
    };
    extern struct startup_info *startup_info;
    
    /* merge.c */
    struct commit_list;
    int try_merge_command(const char *strategy, size_t xopts_nr,
    		const char **xopts, struct commit_list *common,
    		const char *head_arg, struct commit_list *remotes);
    int checkout_fast_forward(const unsigned char *from,
    			  const unsigned char *to,
    			  int overwrite_ignore);
    
    
    int sane_execvp(const char *file, char *const argv[]);
    
    /*
     * A struct to encapsulate the concept of whether a file has changed
     * since we last checked it. This uses criteria similar to those used
     * for the index.
     */
    struct stat_validity {
    	struct stat_data *sd;
    };
    
    void stat_validity_clear(struct stat_validity *sv);
    
    /*
     * Returns 1 if the path is a regular file (or a symlink to a regular
     * file) and matches the saved stat_validity, 0 otherwise.  A missing
     * or inaccessible file is considered a match if the struct was just
     * initialized, or if the previous update found an inaccessible file.
     */
    int stat_validity_check(struct stat_validity *sv, const char *path);
    
    /*
     * Update the stat_validity from a file opened at descriptor fd. If
     * the file is missing, inaccessible, or not a regular file, then
     * future calls to stat_validity_check will match iff one of those
     * conditions continues to be true.
     */
    void stat_validity_update(struct stat_validity *sv, int fd);
    
    int versioncmp(const char *s1, const char *s2);
    void sleep_millisec(int millisec);
    
    #endif /* CACHE_H */