include/git2/tree.h

/*
 * 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_tree_h__
#define INCLUDE_git_tree_h__

#include "common.h"
#include "types.h"
#include "oid.h"
#include "object.h"

/**
 * @file git2/tree.h
 * @brief Git tree parsing, loading routines
 * @defgroup git_tree Git tree parsing, loading routines
 * @ingroup Git
 * @{
 */
GIT_BEGIN_DECL

/**
 * Lookup a tree object from the repository.
 *
 * @param out Pointer to the looked up tree
 * @param repo The repo to use when locating the tree.
 * @param id Identity of the tree to locate.
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_tree_lookup(
	git_tree **out, git_repository *repo, const git_oid *id);

/**
 * Lookup a tree object from the repository,
 * given a prefix of its identifier (short id).
 *
 * @see git_object_lookup_prefix
 *
 * @param out pointer to the looked up tree
 * @param repo the repo to use when locating the tree.
 * @param id identity of the tree to locate.
 * @param len the length of the short identifier
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_tree_lookup_prefix(
	git_tree **out,
	git_repository *repo,
	const git_oid *id,
	size_t len);

/**
 * Close an open tree
 *
 * You can no longer use the git_tree pointer after this call.
 *
 * IMPORTANT: You MUST call this method when you stop using a tree to
 * release memory. Failure to do so will cause a memory leak.
 *
 * @param tree The tree to close
 */
GIT_EXTERN(void) git_tree_free(git_tree *tree);

/**
 * Get the id of a tree.
 *
 * @param tree a previously loaded tree.
 * @return object identity for the tree.
 */
GIT_EXTERN(const git_oid *) git_tree_id(const git_tree *tree);

/**
 * Get the repository that contains the tree.
 *
 * @param tree A previously loaded tree.
 * @return Repository that contains this tree.
 */
GIT_EXTERN(git_repository *) git_tree_owner(const git_tree *tree);

/**
 * Get the number of entries listed in a tree
 *
 * @param tree a previously loaded tree.
 * @return the number of entries in the tree
 */
GIT_EXTERN(size_t) git_tree_entrycount(const git_tree *tree);

/**
 * Lookup a tree entry by its filename
 *
 * This returns a git_tree_entry that is owned by the git_tree.  You don't
 * have to free it, but you must not use it after the git_tree is released.
 *
 * @param tree a previously loaded tree.
 * @param filename the filename of the desired entry
 * @return the tree entry; NULL if not found
 */
GIT_EXTERN(const git_tree_entry *) git_tree_entry_byname(
	const git_tree *tree, const char *filename);

/**
 * Lookup a tree entry by its position in the tree
 *
 * This returns a git_tree_entry that is owned by the git_tree.  You don't
 * have to free it, but you must not use it after the git_tree is released.
 *
 * @param tree a previously loaded tree.
 * @param idx the position in the entry list
 * @return the tree entry; NULL if not found
 */
GIT_EXTERN(const git_tree_entry *) git_tree_entry_byindex(
	const git_tree *tree, size_t idx);

/**
 * Lookup a tree entry by SHA value.
 *
 * This returns a git_tree_entry that is owned by the git_tree.  You don't
 * have to free it, but you must not use it after the git_tree is released.
 *
 * Warning: this must examine every entry in the tree, so it is not fast.
 *
 * @param tree a previously loaded tree.
 * @param id the sha being looked for
 * @return the tree entry; NULL if not found
 */
GIT_EXTERN(const git_tree_entry *) git_tree_entry_byid(
	const git_tree *tree, const git_oid *id);

/**
 * Retrieve a tree entry contained in a tree or in any of its subtrees,
 * given its relative path.
 *
 * Unlike the other lookup functions, the returned tree entry is owned by
 * the user and must be freed explicitly with `git_tree_entry_free()`.
 *
 * @param out Pointer where to store the tree entry
 * @param root Previously loaded tree which is the root of the relative path
 * @param path Path to the contained entry
 * @return 0 on success; GIT_ENOTFOUND if the path does not exist
 */
GIT_EXTERN(int) git_tree_entry_bypath(
	git_tree_entry **out,
	const git_tree *root,
	const char *path);

/**
 * Duplicate a tree entry
 *
 * Create a copy of a tree entry. The returned copy is owned by the user,
 * and must be freed explicitly with `git_tree_entry_free()`.
 *
 * @param dest pointer where to store the copy
 * @param source tree entry to duplicate
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_tree_entry_dup(git_tree_entry **dest, const git_tree_entry *source);

/**
 * Free a user-owned tree entry
 *
 * IMPORTANT: This function is only needed for tree entries owned by the
 * user, such as the ones returned by `git_tree_entry_dup()` or
 * `git_tree_entry_bypath()`.
 *
 * @param entry The entry to free
 */
GIT_EXTERN(void) git_tree_entry_free(git_tree_entry *entry);

/**
 * Get the filename of a tree entry
 *
 * @param entry a tree entry
 * @return the name of the file
 */
GIT_EXTERN(const char *) git_tree_entry_name(const git_tree_entry *entry);

/**
 * Get the id of the object pointed by the entry
 *
 * @param entry a tree entry
 * @return the oid of the object
 */
GIT_EXTERN(const git_oid *) git_tree_entry_id(const git_tree_entry *entry);

/**
 * Get the type of the object pointed by the entry
 *
 * @param entry a tree entry
 * @return the type of the pointed object
 */
GIT_EXTERN(git_otype) git_tree_entry_type(const git_tree_entry *entry);

/**
 * Get the UNIX file attributes of a tree entry
 *
 * @param entry a tree entry
 * @return filemode as an integer
 */
GIT_EXTERN(git_filemode_t) git_tree_entry_filemode(const git_tree_entry *entry);

/**
 * Get the raw UNIX file attributes of a tree entry
 *
 * This function does not perform any normalization and is only useful
 * if you need to be able to recreate the original tree object.
 *
 * @param entry a tree entry
 * @return filemode as an integer
 */

GIT_EXTERN(git_filemode_t) git_tree_entry_filemode_raw(const git_tree_entry *entry);
/**
 * Compare two tree entries
 *
 * @param e1 first tree entry
 * @param e2 second tree entry
 * @return <0 if e1 is before e2, 0 if e1 == e2, >0 if e1 is after e2
 */
GIT_EXTERN(int) git_tree_entry_cmp(const git_tree_entry *e1, const git_tree_entry *e2);

/**
 * Convert a tree entry to the git_object it points to.
 *
 * You must call `git_object_free()` on the object when you are done with it.
 *
 * @param object_out pointer to the converted object
 * @param repo repository where to lookup the pointed object
 * @param entry a tree entry
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_tree_entry_to_object(
	git_object **object_out,
	git_repository *repo,
	const git_tree_entry *entry);

/**
 * Create a new tree builder.
 *
 * The tree builder can be used to create or modify trees in memory and
 * write them as tree objects to the database.
 *
 * If the `source` parameter is not NULL, the tree builder will be
 * initialized with the entries of the given tree.
 *
 * If the `source` parameter is NULL, the tree builder will start with no
 * entries and will have to be filled manually.
 *
 * @param out Pointer where to store the tree builder
 * @param repo Repository in which to store the object
 * @param source Source tree to initialize the builder (optional)
 * @return 0 on success; error code otherwise
 */
GIT_EXTERN(int) git_treebuilder_new(
	git_treebuilder **out, git_repository *repo, const git_tree *source);

/**
 * Clear all the entires in the builder
 *
 * @param bld Builder to clear
 */
GIT_EXTERN(void) git_treebuilder_clear(git_treebuilder *bld);

/**
 * Get the number of entries listed in a treebuilder
 *
 * @param bld a previously loaded treebuilder.
 * @return the number of entries in the treebuilder
 */
GIT_EXTERN(unsigned int) git_treebuilder_entrycount(git_treebuilder *bld);

/**
 * Free a tree builder
 *
 * This will clear all the entries and free to builder.
 * Failing to free the builder after you're done using it
 * will result in a memory leak
 *
 * @param bld Builder to free
 */
GIT_EXTERN(void) git_treebuilder_free(git_treebuilder *bld);

/**
 * Get an entry from the builder from its filename
 *
 * The returned entry is owned by the builder and should
 * not be freed manually.
 *
 * @param bld Tree builder
 * @param filename Name of the entry
 * @return pointer to the entry; NULL if not found
 */
GIT_EXTERN(const git_tree_entry *) git_treebuilder_get(
	git_treebuilder *bld, const char *filename);

/**
 * Add or update an entry to the builder
 *
 * Insert a new entry for `filename` in the builder with the
 * given attributes.
 *
 * If an entry named `filename` already exists, its attributes
 * will be updated with the given ones.
 *
 * The optional pointer `out` can be used to retrieve a pointer to the
 * newly created/updated entry.  Pass NULL if you do not need it. The
 * pointer may not be valid past the next operation in this
 * builder. Duplicate the entry if you want to keep it.
 *
 * No attempt is being made to ensure that the provided oid points
 * to an existing git object in the object database, nor that the
 * attributes make sense regarding the type of the pointed at object.
 *
 * @param out Pointer to store the entry (optional)
 * @param bld Tree builder
 * @param filename Filename of the entry
 * @param id SHA1 oid of the entry
 * @param filemode Folder attributes of the entry. This parameter must
 *			be valued with one of the following entries: 0040000, 0100644,
 *			0100755, 0120000 or 0160000.
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_treebuilder_insert(
	const git_tree_entry **out,
	git_treebuilder *bld,
	const char *filename,
	const git_oid *id,
	git_filemode_t filemode);

/**
 * Remove an entry from the builder by its filename
 *
 * @param bld Tree builder
 * @param filename Filename of the entry to remove
 */
GIT_EXTERN(int) git_treebuilder_remove(
	git_treebuilder *bld, const char *filename);

/**
 * Callback for git_treebuilder_filter
 *
 * The return value is treated as a boolean, with zero indicating that the
 * entry should be left alone and any non-zero value meaning that the
 * entry should be removed from the treebuilder list (i.e. filtered out).
 */
typedef int (*git_treebuilder_filter_cb)(
	const git_tree_entry *entry, void *payload);

/**
 * Selectively remove entries in the tree
 *
 * The `filter` callback will be called for each entry in the tree with a
 * pointer to the entry and the provided `payload`; if the callback returns
 * non-zero, the entry will be filtered (removed from the builder).
 *
 * @param bld Tree builder
 * @param filter Callback to filter entries
 * @param payload Extra data to pass to filter callback
 */
GIT_EXTERN(void) git_treebuilder_filter(
	git_treebuilder *bld,
	git_treebuilder_filter_cb filter,
	void *payload);

/**
 * Write the contents of the tree builder as a tree object
 *
 * The tree builder will be written to the given `repo`, and its
 * identifying SHA1 hash will be stored in the `id` pointer.
 *
 * @param id Pointer to store the OID of the newly written tree
 * @param bld Tree builder to write
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_treebuilder_write(
	git_oid *id, git_treebuilder *bld);

/**
 * Write the contents of the tree builder as a tree object
 * using a shared git_buf.
 *
 * @see git_treebuilder_write
 *
 * @param oid Pointer to store the OID of the newly written tree
 * @param bld Tree builder to write
 * @param tree Shared buffer for writing the tree. Will be grown as necessary.
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_treebuilder_write_with_buffer(
	git_oid *oid, git_treebuilder *bld, git_buf *tree);

/** Callback for the tree traversal method */
typedef int (*git_treewalk_cb)(
	const char *root, const git_tree_entry *entry, void *payload);

/** Tree traversal modes */
typedef enum {
	GIT_TREEWALK_PRE = 0, /* Pre-order */
	GIT_TREEWALK_POST = 1, /* Post-order */
} git_treewalk_mode;

/**
 * Traverse the entries in a tree and its subtrees in post or pre order.
 *
 * The entries will be traversed in the specified order, children subtrees
 * will be automatically loaded as required, and the `callback` will be
 * called once per entry with the current (relative) root for the entry and
 * the entry data itself.
 *
 * If the callback returns a positive value, the passed entry will be
 * skipped on the traversal (in pre mode). A negative value stops the walk.
 *
 * @param tree The tree to walk
 * @param mode Traversal mode (pre or post-order)
 * @param callback Function to call on each tree entry
 * @param payload Opaque pointer to be passed on each callback
 * @return 0 or an error code
 */
GIT_EXTERN(int) git_tree_walk(
	const git_tree *tree,
	git_treewalk_mode mode,
	git_treewalk_cb callback,
	void *payload);

/**
 * Create an in-memory copy of a tree. The copy must be explicitly
 * free'd or it will leak.
 *
 * @param out Pointer to store the copy of the tree
 * @param source Original tree to copy
 */
GIT_EXTERN(int) git_tree_dup(git_tree **out, git_tree *source);

/**
 * The kind of update to perform
 */
typedef enum {
	/** Update or insert an entry at the specified path */
	GIT_TREE_UPDATE_UPSERT,
	/** Remove an entry from the specified path */
	GIT_TREE_UPDATE_REMOVE,
} git_tree_update_t;

/**
 * An action to perform during the update of a tree
 */
typedef struct {
	/** Update action. If it's an removal, only the path is looked at */
	git_tree_update_t action;
	/** The entry's id */
	git_oid id;
	/** The filemode/kind of object */
	git_filemode_t filemode;
	/** The full path from the root tree */
	const char *path;
} git_tree_update;

/**
 * Create a tree based on another one with the specified modifications
 *
 * Given the `baseline` perform the changes described in the list of
 * `updates` and create a new tree.
 *
 * This function is optimized for common file/directory addition, removal and
 * replacement in trees. It is much more efficient than reading the tree into a
 * `git_index` and modifying that, but in exchange it is not as flexible.
 *
 * Deleting and adding the same entry is undefined behaviour, changing
 * a tree to a blob or viceversa is not supported.
 *
 * @param out id of the new tree
 * @param repo the repository in which to create the tree, must be the
 * same as for `baseline`
 * @param baseline the tree to base these changes on
 * @param nupdates the number of elements in the update list
 * @param updates the list of updates to perform
 */
GIT_EXTERN(int) git_tree_create_updated(git_oid *out, git_repository *repo, git_tree *baseline, size_t nupdates, const git_tree_update *updates);

/** @} */

GIT_END_DECL
#endif