/*
 * 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_git_index_h__
#define INCLUDE_git_index_h__

#include "common.h"
#include "indexer.h"
#include "types.h"
#include "oid.h"
#include "strarray.h"

/**
 * @file git2/index.h
 * @brief Index (aka "cache" aka "staging area")
 * @defgroup git_index Git index parsing and manipulation routines
 * @ingroup Git
 *
 * The index (or "cache", or "staging area") is the contents of the
 * next commit. In addition, the index stores other data, such as
 * conflicts that occurred during the last merge operation, and
 * the "treecache" to speed up various on-disk operations.
 * @{
 */
GIT_BEGIN_DECL

/** Time structure used in a git index entry */
typedef struct {
	int32_t seconds;
	/* nsec should not be stored as time_t compatible */
	uint32_t nanoseconds;
} git_index_time;

/**
 * In-memory representation of a file entry in the index.
 *
 * This is a public structure that represents a file entry in the index.
 * The meaning of the fields corresponds to core Git's documentation (in
 * "Documentation/technical/index-format.txt").
 *
 * The `flags` field consists of a number of bit fields which can be
 * accessed via the first set of `GIT_INDEX_ENTRY_...` bitmasks below.
 * These flags are all read from and persisted to disk.
 *
 * The `flags_extended` field also has a number of bit fields which can be
 * accessed via the later `GIT_INDEX_ENTRY_...` bitmasks below.  Some of
 * these flags are read from and written to disk, but some are set aside
 * for in-memory only reference.
 *
 * Note that the time and size fields are truncated to 32 bits. This
 * is enough to detect changes, which is enough for the index to
 * function as a cache, but it should not be taken as an authoritative
 * source for that data.
 */
typedef struct git_index_entry {
	git_index_time ctime;
	git_index_time mtime;

	uint32_t dev;
	uint32_t ino;
	uint32_t mode;
	uint32_t uid;
	uint32_t gid;
	uint32_t file_size;

	git_oid id;

	uint16_t flags;
	uint16_t flags_extended;

	const char *path;
} git_index_entry;

/**
 * Bitmasks for on-disk fields of `git_index_entry`'s `flags`
 *
 * These bitmasks match the four fields in the `git_index_entry` `flags`
 * value both in memory and on disk.  You can use them to interpret the
 * data in the `flags`.
 */

/** Mask for name length */
#define GIT_INDEX_ENTRY_NAMEMASK  (0x0fff)
/** Mask for index entry stage */
#define GIT_INDEX_ENTRY_STAGEMASK (0x3000)
/** Shift bits for index entry */
#define GIT_INDEX_ENTRY_STAGESHIFT 12

/**
 * Flags for index entries
 */
typedef enum {
	GIT_INDEX_ENTRY_EXTENDED  = (0x4000),
	GIT_INDEX_ENTRY_VALID     = (0x8000)
} git_index_entry_flag_t;

/**
 * Macro to get the stage value (0 for the "main index", or a conflict
 * value) from an index entry.
 */
#define GIT_INDEX_ENTRY_STAGE(E) \
	(((E)->flags & GIT_INDEX_ENTRY_STAGEMASK) >> GIT_INDEX_ENTRY_STAGESHIFT)

/**
 * Macro to set the stage value (0 for the "main index", or a conflict
 * value) for an index entry.
 */
#define GIT_INDEX_ENTRY_STAGE_SET(E,S) do { \
	(E)->flags = ((E)->flags & ~GIT_INDEX_ENTRY_STAGEMASK) | \
		(((S) & 0x03) << GIT_INDEX_ENTRY_STAGESHIFT); } while (0)

/**
 * Bitmasks for on-disk fields of `git_index_entry`'s `flags_extended`
 *
 * In memory, the `flags_extended` fields are divided into two parts: the
 * fields that are read from and written to disk, and other fields that
 * in-memory only and used by libgit2.  Only the flags in
 * `GIT_INDEX_ENTRY_EXTENDED_FLAGS` will get saved on-disk.
 *
 * Thee first three bitmasks match the three fields in the
 * `git_index_entry` `flags_extended` value that belong on disk.  You
 * can use them to interpret the data in the `flags_extended`.
 *
 * The rest of the bitmasks match the other fields in the `git_index_entry`
 * `flags_extended` value that are only used in-memory by libgit2.
 * You can use them to interpret the data in the `flags_extended`.
 *
 */
typedef enum {
	GIT_INDEX_ENTRY_INTENT_TO_ADD  =  (1 << 13),
	GIT_INDEX_ENTRY_SKIP_WORKTREE  =  (1 << 14),

	GIT_INDEX_ENTRY_EXTENDED_FLAGS =  (GIT_INDEX_ENTRY_INTENT_TO_ADD | GIT_INDEX_ENTRY_SKIP_WORKTREE),

	GIT_INDEX_ENTRY_UPTODATE       =  (1 << 2)
} git_index_entry_extended_flag_t;

/** Capabilities of system that affect index actions. */
typedef enum {
	GIT_INDEX_CAPABILITY_IGNORE_CASE = 1,
	GIT_INDEX_CAPABILITY_NO_FILEMODE = 2,
	GIT_INDEX_CAPABILITY_NO_SYMLINKS = 4,
	GIT_INDEX_CAPABILITY_FROM_OWNER  = -1
} git_index_capability_t;


/**
 * Callback for APIs that add/remove/update files matching pathspec
 *
 * @param path the path
 * @param matched_pathspec the given pathspec
 * @param payload the user-specified payload
 * @return 0 to continue with the index operation, positive number to         skip this file for the index operation, negative number on failure
 */
typedef int GIT_CALLBACK(git_index_matched_path_cb)(
	const char *path, const char *matched_pathspec, void *payload);

/** Flags for APIs that add files matching pathspec */
typedef enum {
	GIT_INDEX_ADD_DEFAULT = 0,
	GIT_INDEX_ADD_FORCE = (1u << 0),
	GIT_INDEX_ADD_DISABLE_PATHSPEC_MATCH = (1u << 1),
	GIT_INDEX_ADD_CHECK_PATHSPEC = (1u << 2)
} git_index_add_option_t;

/** Git index stage states */
typedef enum {
	/**
	 * Match any index stage.
	 *
	 * Some index APIs take a stage to match; pass this value to match
	 * any entry matching the path regardless of stage.
	 */
	GIT_INDEX_STAGE_ANY = -1,

	/** A normal staged file in the index. */
	GIT_INDEX_STAGE_NORMAL = 0,

	/** The ancestor side of a conflict. */
	GIT_INDEX_STAGE_ANCESTOR = 1,

	/** The "ours" side of a conflict. */
	GIT_INDEX_STAGE_OURS = 2,

	/** The "theirs" side of a conflict. */
	GIT_INDEX_STAGE_THEIRS = 3
} git_index_stage_t;

#ifdef GIT_EXPERIMENTAL_SHA256

/**
 * The options for opening or creating an index.
 *
 * Initialize with `GIT_INDEX_OPTIONS_INIT`. Alternatively, you can
 * use `git_index_options_init`.
 *
 * @options[version] GIT_INDEX_OPTIONS_VERSION
 * @options[init_macro] GIT_INDEX_OPTIONS_INIT
 * @options[init_function] git_index_options_init
 */
typedef struct git_index_options {
	unsigned int version; /**< The version */

	/**
	 * The object ID type for the object IDs that exist in the index.
	 *
	 * If this is not specified, this defaults to `GIT_OID_SHA1`.
	 */
	git_oid_t oid_type;
} git_index_options;

/** Current version for the `git_index_options` structure */
#define GIT_INDEX_OPTIONS_VERSION 1

/** Static constructor for `git_index_options` */
#define GIT_INDEX_OPTIONS_INIT { GIT_INDEX_OPTIONS_VERSION }

/**
 * Initialize git_index_options structure
 *
 * Initializes a `git_index_options` with default values. Equivalent to creating
 * an instance with GIT_INDEX_OPTIONS_INIT.
 *
 * @param opts The `git_index_options` struct to initialize.
 * @param version The struct version; pass `GIT_INDEX_OPTIONS_VERSION`.
 * @return Zero on success; -1 on failure.
 */
GIT_EXTERN(int) git_index_options_init(
	git_index_options *opts,
	unsigned int version);

/**
 * Creates a new bare Git index object, without a repository to back
 * it. This index object is capable of storing SHA256 objects.
 *
 * @param index_out the pointer for the new index
 * @param index_path the path to the index file in disk
 * @param opts the options for opening the index, or NULL
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_open(
	git_index **index_out,
	const char *index_path,
	const git_index_options *opts);

/**
 * Create an in-memory index object.
 *
 * @param index_out the pointer for the new index
 * @param opts the options for opening the index, or NULL
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_new(git_index **index_out, const git_index_options *opts);

#else

/**
 * Create a new bare Git index object as a memory representation
 * of the Git index file in 'index_path', without a repository
 * to back it.
 *
 * Since there is no ODB or working directory behind this index,
 * any Index methods which rely on these (e.g. index_add_bypath)
 * will fail with the GIT_ERROR error code.
 *
 * If you need to access the index of an actual repository,
 * use the `git_repository_index` wrapper.
 *
 * The index must be freed once it's no longer in use.
 *
 * @param index_out the pointer for the new index
 * @param index_path the path to the index file in disk
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_open(git_index **index_out, const char *index_path);

/**
 * Create an in-memory index object.
 *
 * This index object cannot be read/written to the filesystem,
 * but may be used to perform in-memory index operations.
 *
 * The index must be freed once it's no longer in use.
 *
 * @param index_out the pointer for the new index
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_new(git_index **index_out);

#endif

/**
 * Free an existing index object.
 *
 * @param index an existing index object
 */
GIT_EXTERN(void) git_index_free(git_index *index);

/**
 * Get the repository this index relates to
 *
 * @param index The index
 * @return A pointer to the repository
 */
GIT_EXTERN(git_repository *) git_index_owner(const git_index *index);

/**
 * Read index capabilities flags.
 *
 * @param index An existing index object
 * @return A combination of GIT_INDEX_CAPABILITY values
 */
GIT_EXTERN(int) git_index_caps(const git_index *index);

/**
 * Set index capabilities flags.
 *
 * If you pass `GIT_INDEX_CAPABILITY_FROM_OWNER` for the caps, then
 * capabilities will be read from the config of the owner object,
 * looking at `core.ignorecase`, `core.filemode`, `core.symlinks`.
 *
 * @param index An existing index object
 * @param caps A combination of GIT_INDEX_CAPABILITY values
 * @return 0 on success, -1 on failure
 */
GIT_EXTERN(int) git_index_set_caps(git_index *index, int caps);

/**
 * Get index on-disk version.
 *
 * Valid return values are 2, 3, or 4.  If 3 is returned, an index
 * with version 2 may be written instead, if the extension data in
 * version 3 is not necessary.
 *
 * @param index An existing index object
 * @return the index version
 */
GIT_EXTERN(unsigned int) git_index_version(git_index *index);

/**
 * Set index on-disk version.
 *
 * Valid values are 2, 3, or 4.  If 2 is given, git_index_write may
 * write an index with version 3 instead, if necessary to accurately
 * represent the index.
 *
 * @param index An existing index object
 * @param version The new version number
 * @return 0 on success, -1 on failure
 */
GIT_EXTERN(int) git_index_set_version(git_index *index, unsigned int version);

/**
 * Update the contents of an existing index object in memory by reading
 * from the hard disk.
 *
 * If `force` is true, this performs a "hard" read that discards in-memory
 * changes and always reloads the on-disk index data.  If there is no
 * on-disk version, the index will be cleared.
 *
 * If `force` is false, this does a "soft" read that reloads the index
 * data from disk only if it has changed since the last time it was
 * loaded.  Purely in-memory index data will be untouched.  Be aware: if
 * there are changes on disk, unwritten in-memory changes are discarded.
 *
 * @param index an existing index object
 * @param force if true, always reload, vs. only read if file has changed
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_read(git_index *index, int force);

/**
 * Write an existing index object from memory back to disk
 * using an atomic file lock.
 *
 * @param index an existing index object
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_write(git_index *index);

/**
 * Get the full path to the index file on disk.
 *
 * @param index an existing index object
 * @return path to index file or NULL for in-memory index
 */
GIT_EXTERN(const char *) git_index_path(const git_index *index);

#ifndef GIT_DEPRECATE_HARD
/**
 * Get the checksum of the index
 *
 * This checksum is the SHA-1 hash over the index file (except the
 * last 20 bytes which are the checksum itself). In cases where the
 * index does not exist on-disk, it will be zeroed out.
 *
 * @deprecated this function is deprecated with no replacement
 * @param index an existing index object
 * @return a pointer to the checksum of the index
 */
GIT_EXTERN(const git_oid *) git_index_checksum(git_index *index);
#endif

/**
 * Read a tree into the index file with stats
 *
 * The current index contents will be replaced by the specified tree.
 *
 * @param index an existing index object
 * @param tree tree to read
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_read_tree(git_index *index, const git_tree *tree);

/**
 * Write the index as a tree
 *
 * This method will scan the index and write a representation
 * of its current state back to disk; it recursively creates
 * tree objects for each of the subtrees stored in the index,
 * but only returns the OID of the root tree. This is the OID
 * that can be used e.g. to create a commit.
 *
 * The index instance cannot be bare, and needs to be associated
 * to an existing repository.
 *
 * The index must not contain any file in conflict.
 *
 * @param out Pointer where to store the OID of the written tree
 * @param index Index to write
 * @return 0 on success, GIT_EUNMERGED when the index is not clean
 * or an error code
 */
GIT_EXTERN(int) git_index_write_tree(git_oid *out, git_index *index);

/**
 * Write the index as a tree to the given repository
 *
 * This method will do the same as `git_index_write_tree`, but
 * letting the user choose the repository where the tree will
 * be written.
 *
 * The index must not contain any file in conflict.
 *
 * @param out Pointer where to store OID of the written tree
 * @param index Index to write
 * @param repo Repository where to write the tree
 * @return 0 on success, GIT_EUNMERGED when the index is not clean
 * or an error code
 */
GIT_EXTERN(int) git_index_write_tree_to(git_oid *out, git_index *index, git_repository *repo);

/**@}*/

/** @name Raw Index Entry Functions
 *
 * These functions work on index entries, and allow for raw manipulation
 * of the entries.
 */
/**@{*/

/* Index entry manipulation */

/**
 * Get the count of entries currently in the index
 *
 * @param index an existing index object
 * @return integer of count of current entries
 */
GIT_EXTERN(size_t) git_index_entrycount(const git_index *index);

/**
 * Clear the contents (all the entries) of an index object.
 *
 * This clears the index object in memory; changes must be explicitly
 * written to disk for them to take effect persistently.
 *
 * @param index an existing index object
 * @return 0 on success, error code < 0 on failure
 */
GIT_EXTERN(int) git_index_clear(git_index *index);

/**
 * Get a pointer to one of the entries in the index
 *
 * The entry is not modifiable and should not be freed.  Because the
 * `git_index_entry` struct is a publicly defined struct, you should
 * be able to make your own permanent copy of the data if necessary.
 *
 * @param index an existing index object
 * @param n the position of the entry
 * @return a pointer to the entry; NULL if out of bounds
 */
GIT_EXTERN(const git_index_entry *) git_index_get_byindex(
	git_index *index, size_t n);

/**
 * Get a pointer to one of the entries in the index
 *
 * The entry is not modifiable and should not be freed.  Because the
 * `git_index_entry` struct is a publicly defined struct, you should
 * be able to make your own permanent copy of the data if necessary.
 *
 * @param index an existing index object
 * @param path path to search
 * @param stage stage to search
 * @return a pointer to the entry; NULL if it was not found
 */
GIT_EXTERN(const git_index_entry *) git_index_get_bypath(
	git_index *index, const char *path, int stage);

/**
 * Remove an entry from the index
 *
 * @param index an existing index object
 * @param path path to search
 * @param stage stage to search
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_remove(git_index *index, const char *path, int stage);

/**
 * Remove all entries from the index under a given directory
 *
 * @param index an existing index object
 * @param dir container directory path
 * @param stage stage to search
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_remove_directory(
	git_index *index, const char *dir, int stage);

/**
 * Add or update an index entry from an in-memory struct
 *
 * If a previous index entry exists that has the same path and stage
 * as the given 'source_entry', it will be replaced.  Otherwise, the
 * 'source_entry' will be added.
 *
 * A full copy (including the 'path' string) of the given
 * 'source_entry' will be inserted on the index.
 *
 * @param index an existing index object
 * @param source_entry new entry object
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_add(git_index *index, const git_index_entry *source_entry);

/**
 * Return the stage number from a git index entry
 *
 * This entry is calculated from the entry's flag attribute like this:
 *
 *    (entry->flags & GIT_INDEX_ENTRY_STAGEMASK) >> GIT_INDEX_ENTRY_STAGESHIFT
 *
 * @param entry The entry
 * @return the stage number
 */
GIT_EXTERN(int) git_index_entry_stage(const git_index_entry *entry);

/**
 * Return whether the given index entry is a conflict (has a high stage
 * entry).  This is simply shorthand for `git_index_entry_stage > 0`.
 *
 * @param entry The entry
 * @return 1 if the entry is a conflict entry, 0 otherwise
 */
GIT_EXTERN(int) git_index_entry_is_conflict(const git_index_entry *entry);

/**@}*/

/** @name Index Entry Iteration Functions
 *
 * These functions provide an iterator for index entries.
 */
/**@{*/

/**
 * Create an iterator that will return every entry contained in the
 * index at the time of creation.  Entries are returned in order,
 * sorted by path.  This iterator is backed by a snapshot that allows
 * callers to modify the index while iterating without affecting the
 * iterator.
 *
 * @param iterator_out The newly created iterator
 * @param index The index to iterate
 * @return 0 or an error code.
 */
GIT_EXTERN(int) git_index_iterator_new(
	git_index_iterator **iterator_out,
	git_index *index);

/**
 * Return the next index entry in-order from the iterator.
 *
 * @param out Pointer to store the index entry in
 * @param iterator The iterator
 * @return 0, GIT_ITEROVER on iteration completion or an error code
 */
GIT_EXTERN(int) git_index_iterator_next(
	const git_index_entry **out,
	git_index_iterator *iterator);

/**
 * Free the index iterator
 *
 * @param iterator The iterator to free
 */
GIT_EXTERN(void) git_index_iterator_free(git_index_iterator *iterator);

/**@}*/

/** @name Workdir Index Entry Functions
 *
 * These functions work on index entries specifically in the working
 * directory (ie, stage 0).
 */
/**@{*/

/**
 * Add or update an index entry from a file on disk
 *
 * The file `path` must be relative to the repository's
 * working folder and must be readable.
 *
 * This method will fail in bare index instances.
 *
 * This forces the file to be added to the index, not looking
 * at gitignore rules.  Those rules can be evaluated through
 * the git_status APIs (in status.h) before calling this.
 *
 * If this file currently is the result of a merge conflict, this
 * file will no longer be marked as conflicting.  The data about
 * the conflict will be moved to the "resolve undo" (REUC) section.
 *
 * @param index an existing index object
 * @param path filename to add
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_add_bypath(git_index *index, const char *path);

/**
 * Add or update an index entry from a buffer in memory
 *
 * This method will create a blob in the repository that owns the
 * index and then add the index entry to the index.  The `path` of the
 * entry represents the position of the blob relative to the
 * repository's root folder.
 *
 * If a previous index entry exists that has the same path as the
 * given 'entry', it will be replaced.  Otherwise, the 'entry' will be
 * added.
 *
 * This forces the file to be added to the index, not looking
 * at gitignore rules.  Those rules can be evaluated through
 * the git_status APIs (in status.h) before calling this.
 *
 * If this file currently is the result of a merge conflict, this
 * file will no longer be marked as conflicting.  The data about
 * the conflict will be moved to the "resolve undo" (REUC) section.
 *
 * @param index an existing index object
 * @param entry filename to add
 * @param buffer data to be written into the blob
 * @param len length of the data
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_add_from_buffer(
	git_index *index,
	const git_index_entry *entry,
	const void *buffer, size_t len);

/**
 * Remove an index entry corresponding to a file on disk
 *
 * The file `path` must be relative to the repository's
 * working folder.  It may exist.
 *
 * If this file currently is the result of a merge conflict, this
 * file will no longer be marked as conflicting.  The data about
 * the conflict will be moved to the "resolve undo" (REUC) section.
 *
 * @param index an existing index object
 * @param path filename to remove
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_remove_bypath(git_index *index, const char *path);

/**
 * Add or update index entries matching files in the working directory.
 *
 * This method will fail in bare index instances.
 *
 * The `pathspec` is a list of file names or shell glob patterns that will
 * be matched against files in the repository's working directory.  Each
 * file that matches will be added to the index (either updating an
 * existing entry or adding a new entry).  You can disable glob expansion
 * and force exact matching with the `GIT_INDEX_ADD_DISABLE_PATHSPEC_MATCH`
 * flag.
 *
 * Files that are ignored will be skipped (unlike `git_index_add_bypath`).
 * If a file is already tracked in the index, then it *will* be updated
 * even if it is ignored.  Pass the `GIT_INDEX_ADD_FORCE` flag to skip
 * the checking of ignore rules.
 *
 * To emulate `git add -A` and generate an error if the pathspec contains
 * the exact path of an ignored file (when not using FORCE), add the
 * `GIT_INDEX_ADD_CHECK_PATHSPEC` flag.  This checks that each entry
 * in the `pathspec` that is an exact match to a filename on disk is
 * either not ignored or already in the index.  If this check fails, the
 * function will return GIT_EINVALIDSPEC.
 *
 * To emulate `git add -A` with the "dry-run" option, just use a callback
 * function that always returns a positive value.  See below for details.
 *
 * If any files are currently the result of a merge conflict, those files
 * will no longer be marked as conflicting.  The data about the conflicts
 * will be moved to the "resolve undo" (REUC) section.
 *
 * If you provide a callback function, it will be invoked on each matching
 * item in the working directory immediately *before* it is added to /
 * updated in the index.  Returning zero will add the item to the index,
 * greater than zero will skip the item, and less than zero will abort the
 * scan and return that value to the caller.
 *
 * @param index an existing index object
 * @param pathspec array of path patterns
 * @param flags combination of git_index_add_option_t flags
 * @param callback notification callback for each added/updated path (also
 *                 gets index of matching pathspec entry); can be NULL;
 *                 return 0 to add, >0 to skip, <0 to abort scan.
 * @param payload payload passed through to callback function
 * @return 0 on success, negative callback return value, or error code
 */
GIT_EXTERN(int) git_index_add_all(
	git_index *index,
	const git_strarray *pathspec,
	unsigned int flags,
	git_index_matched_path_cb callback,
	void *payload);

/**
 * Remove all matching index entries.
 *
 * If you provide a callback function, it will be invoked on each matching
 * item in the index immediately *before* it is removed.  Return 0 to
 * remove the item, > 0 to skip the item, and < 0 to abort the scan.
 *
 * @param index An existing index object
 * @param pathspec array of path patterns
 * @param callback notification callback for each removed path (also
 *                 gets index of matching pathspec entry); can be NULL;
 *                 return 0 to add, >0 to skip, <0 to abort scan.
 * @param payload payload passed through to callback function
 * @return 0 on success, negative callback return value, or error code
 */
GIT_EXTERN(int) git_index_remove_all(
	git_index *index,
	const git_strarray *pathspec,
	git_index_matched_path_cb callback,
	void *payload);

/**
 * Update all index entries to match the working directory
 *
 * This method will fail in bare index instances.
 *
 * This scans the existing index entries and synchronizes them with the
 * working directory, deleting them if the corresponding working directory
 * file no longer exists otherwise updating the information (including
 * adding the latest version of file to the ODB if needed).
 *
 * If you provide a callback function, it will be invoked on each matching
 * item in the index immediately *before* it is updated (either refreshed
 * or removed depending on working directory state).  Return 0 to proceed
 * with updating the item, > 0 to skip the item, and < 0 to abort the scan.
 *
 * @param index An existing index object
 * @param pathspec array of path patterns
 * @param callback notification callback for each updated path (also
 *                 gets index of matching pathspec entry); can be NULL;
 *                 return 0 to add, >0 to skip, <0 to abort scan.
 * @param payload payload passed through to callback function
 * @return 0 on success, negative callback return value, or error code
 */
GIT_EXTERN(int) git_index_update_all(
	git_index *index,
	const git_strarray *pathspec,
	git_index_matched_path_cb callback,
	void *payload);

/**
 * Find the first position of any entries which point to given
 * path in the Git index.
 *
 * @param at_pos the address to which the position of the index entry is written (optional)
 * @param index an existing index object
 * @param path path to search
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_find(size_t *at_pos, git_index *index, const char *path);

/**
 * Find the first position of any entries matching a prefix. To find the first position
 * of a path inside a given folder, suffix the prefix with a '/'.
 *
 * @param at_pos the address to which the position of the index entry is written (optional)
 * @param index an existing index object
 * @param prefix the prefix to search for
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_find_prefix(size_t *at_pos, git_index *index, const char *prefix);

/**@}*/

/** @name Conflict Index Entry Functions
 *
 * These functions work on conflict index entries specifically (ie, stages 1-3)
 */
/**@{*/

/**
 * Add or update index entries to represent a conflict.  Any staged
 * entries that exist at the given paths will be removed.
 *
 * The entries are the entries from the tree included in the merge.  Any
 * entry may be null to indicate that that file was not present in the
 * trees during the merge.  For example, ancestor_entry may be NULL to
 * indicate that a file was added in both branches and must be resolved.
 *
 * @param index an existing index object
 * @param ancestor_entry the entry data for the ancestor of the conflict
 * @param our_entry the entry data for our side of the merge conflict
 * @param their_entry the entry data for their side of the merge conflict
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_conflict_add(
	git_index *index,
	const git_index_entry *ancestor_entry,
	const git_index_entry *our_entry,
	const git_index_entry *their_entry);

/**
 * Get the index entries that represent a conflict of a single file.
 *
 * The entries are not modifiable and should not be freed.  Because the
 * `git_index_entry` struct is a publicly defined struct, you should
 * be able to make your own permanent copy of the data if necessary.
 *
 * @param ancestor_out Pointer to store the ancestor entry
 * @param our_out Pointer to store the our entry
 * @param their_out Pointer to store the their entry
 * @param index an existing index object
 * @param path path to search
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_conflict_get(
	const git_index_entry **ancestor_out,
	const git_index_entry **our_out,
	const git_index_entry **their_out,
	git_index *index,
	const char *path);

/**
 * Removes the index entries that represent a conflict of a single file.
 *
 * @param index an existing index object
 * @param path path to remove conflicts for
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_conflict_remove(git_index *index, const char *path);

/**
 * Remove all conflicts in the index (entries with a stage greater than 0).
 *
 * @param index an existing index object
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_conflict_cleanup(git_index *index);

/**
 * Determine if the index contains entries representing file conflicts.
 *
 * @param index An existing index object.
 * @return 1 if at least one conflict is found, 0 otherwise.
 */
GIT_EXTERN(int) git_index_has_conflicts(const git_index *index);

/**
 * Create an iterator for the conflicts in the index.
 *
 * The index must not be modified while iterating; the results are undefined.
 *
 * @param iterator_out The newly created conflict iterator
 * @param index The index to scan
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_index_conflict_iterator_new(
	git_index_conflict_iterator **iterator_out,
	git_index *index);

/**
 * Returns the current conflict (ancestor, ours and theirs entry) and
 * advance the iterator internally to the next value.
 *
 * @param ancestor_out Pointer to store the ancestor side of the conflict
 * @param our_out Pointer to store our side of the conflict
 * @param their_out Pointer to store their side of the conflict
 * @param iterator The conflict iterator.
 * @return 0 (no error), GIT_ITEROVER (iteration is done) or an error code
 *         (negative value)
 */
GIT_EXTERN(int) git_index_conflict_next(
	const git_index_entry **ancestor_out,
	const git_index_entry **our_out,
	const git_index_entry **their_out,
	git_index_conflict_iterator *iterator);

/**
 * Frees a `git_index_conflict_iterator`.
 *
 * @param iterator pointer to the iterator
 */
GIT_EXTERN(void) git_index_conflict_iterator_free(
	git_index_conflict_iterator *iterator);

/** @} */
GIT_END_DECL

#endif
