diff: refactor code to clarify memory ownership of prefixes

[git.git] / config.h

#ifndef CONFIG_H
#define CONFIG_H

#include "hashmap.h"
#include "string-list.h"
#include "repository.h"
#include "parse.h"

/**
 * The config API gives callers a way to access Git configuration files
 * (and files which have the same syntax).
 *
 * General Usage
 * -------------
 *
 * Config files are parsed linearly, and each variable found is passed to a
 * caller-provided callback function. The callback function is responsible
 * for any actions to be taken on the config option, and is free to ignore
 * some options. It is not uncommon for the configuration to be parsed
 * several times during the run of a Git program, with different callbacks
 * picking out different variables useful to themselves.
 */

struct object_id;

/* git_config_parse_key() returns these negated: */
#define CONFIG_INVALID_KEY 1
#define CONFIG_NO_SECTION_OR_NAME 2
/* git_config_set_gently(), git_config_set_multivar_gently() 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)

enum config_scope {
        CONFIG_SCOPE_UNKNOWN = 0,
        CONFIG_SCOPE_SYSTEM,
        CONFIG_SCOPE_GLOBAL,
        CONFIG_SCOPE_LOCAL,
        CONFIG_SCOPE_WORKTREE,
        CONFIG_SCOPE_COMMAND,
        CONFIG_SCOPE_SUBMODULE,
};
const char *config_scope_name(enum config_scope scope);

struct git_config_source {
        unsigned int use_stdin:1;
        const char *file;
        const char *blob;
        enum config_scope scope;
};

enum config_origin_type {
        CONFIG_ORIGIN_UNKNOWN = 0,
        CONFIG_ORIGIN_BLOB,
        CONFIG_ORIGIN_FILE,
        CONFIG_ORIGIN_STDIN,
        CONFIG_ORIGIN_SUBMODULE_BLOB,
        CONFIG_ORIGIN_CMDLINE
};

enum config_event_t {
        CONFIG_EVENT_SECTION,
        CONFIG_EVENT_ENTRY,
        CONFIG_EVENT_WHITESPACE,
        CONFIG_EVENT_COMMENT,
        CONFIG_EVENT_EOF,
        CONFIG_EVENT_ERROR
};

struct config_source;
/*
 * The parser event function (if not NULL) is called with the event type and
 * the begin/end offsets of the parsed elements.
 *
 * Note: for CONFIG_EVENT_ENTRY (i.e. config variables), the trailing newline
 * character is considered part of the element.
 */
typedef int (*config_parser_event_fn_t)(enum config_event_t type,
                                        size_t begin_offset, size_t end_offset,
                                        struct config_source *cs,
                                        void *event_fn_data);

struct config_options {
        unsigned int respect_includes : 1;
        unsigned int ignore_repo : 1;
        unsigned int ignore_worktree : 1;
        unsigned int ignore_cmdline : 1;
        unsigned int system_gently : 1;

        /*
         * For internal use. Include all includeif.hasremoteurl paths without
         * checking if the repo has that remote URL, and when doing so, verify
         * that files included in this way do not configure any remote URLs
         * themselves.
         */
        unsigned int unconditional_remote_url : 1;

        const char *commondir;
        const char *git_dir;
        /*
         * event_fn and event_fn_data are for internal use only. Handles events
         * emitted by the config parser.
         */
        config_parser_event_fn_t event_fn;
        void *event_fn_data;
        enum config_error_action {
                CONFIG_ERROR_UNSET = 0, /* use source-specific default */
                CONFIG_ERROR_DIE, /* die() on error */
                CONFIG_ERROR_ERROR, /* error() on error, return -1 */
                CONFIG_ERROR_SILENT, /* return -1 */
        } error_action;
};

/* Config source metadata for a given config key-value pair */
struct key_value_info {
        const char *filename;
        int linenr;
        enum config_origin_type origin_type;
        enum config_scope scope;
        const char *path;
};
#define KVI_INIT { \
        .filename = NULL, \
        .linenr = -1, \
        .origin_type = CONFIG_ORIGIN_UNKNOWN, \
        .scope = CONFIG_SCOPE_UNKNOWN, \
        .path = NULL, \
}

/* Captures additional information that a config callback can use. */
struct config_context {
        /* Config source metadata for key and value. */
        const struct key_value_info *kvi;
};
#define CONFIG_CONTEXT_INIT { 0 }

/**
 * A config callback function takes four parameters:
 *
 * - the name of the parsed variable. This is in canonical "flat" form: the
 *   section, subsection, and variable segments will be separated by dots,
 *   and the section and variable segments will be all lowercase. E.g.,
 *   `core.ignorecase`, `diff.SomeType.textconv`.
 *
 * - the value of the found variable, as a string. If the variable had no
 *   value specified, the value will be NULL (typically this means it
 *   should be interpreted as boolean true).
 *
 * - the 'config context', that is, additional information about the config
 *   iteration operation provided by the config machinery. For example, this
 *   includes information about the config source being parsed (e.g. the
 *   filename).
 *
 * - a void pointer passed in by the caller of the config API; this can
 *   contain callback-specific data
 *
 * A config callback should return 0 for success, or -1 if the variable
 * could not be parsed properly.
 */
typedef int (*config_fn_t)(const char *, const char *,
                           const struct config_context *, void *);

int git_default_config(const char *, const char *,
                       const struct config_context *, void *);

/**
 * Read a specific file in git-config format.
 * This function takes the same callback and data parameters as `git_config`.
 *
 * Unlike git_config(), this function does not respect includes.
 */
int git_config_from_file(config_fn_t fn, const char *, void *);

int git_config_from_file_with_options(config_fn_t fn, const char *,
                                      void *, enum config_scope,
                                      const struct config_options *);
int git_config_from_mem(config_fn_t fn,
                        const enum config_origin_type,
                        const char *name,
                        const char *buf, size_t len,
                        void *data, enum config_scope scope,
                        const struct config_options *opts);
int git_config_from_blob_oid(config_fn_t fn, const char *name,
                             struct repository *repo,
                             const struct object_id *oid, void *data,
                             enum config_scope scope);
void git_config_push_parameter(const char *text);
void git_config_push_env(const char *spec);
int git_config_from_parameters(config_fn_t fn, void *data);
void read_early_config(config_fn_t cb, void *data);
void read_very_early_config(config_fn_t cb, void *data);

/**
 * Most programs will simply want to look up variables in all config files
 * that Git knows about, using the normal precedence rules. To do this,
 * call `git_config` with a callback function and void data pointer.
 *
 * `git_config` will read all config sources in order of increasing
 * priority. Thus a callback should typically overwrite previously-seen
 * entries with new ones (e.g., if both the user-wide `~/.gitconfig` and
 * repo-specific `.git/config` contain `color.ui`, the config machinery
 * will first feed the user-wide one to the callback, and then the
 * repo-specific one; by overwriting, the higher-priority repo-specific
 * value is left at the end).
 *
 * Unlike git_config_from_file(), this function respects includes.
 */
void git_config(config_fn_t fn, void *);

/**
 * Lets the caller examine config while adjusting some of the default
 * behavior of `git_config`. It should almost never be used by "regular"
 * Git code that is looking up configuration variables.
 * It is intended for advanced callers like `git-config`, which are
 * intentionally tweaking the normal config-lookup process.
 * It takes two extra parameters:
 *
 * - `config_source`
 * If this parameter is non-NULL, it specifies the source to parse for
 * configuration, rather than looking in the usual files. See `struct
 * git_config_source` in `config.h` for details. Regular `git_config` defaults
 * to `NULL`.
 *
 * - `opts`
 * Specify options to adjust the behavior of parsing config files. See `struct
 * config_options` in `config.h` for details. As an example: regular `git_config`
 * sets `opts.respect_includes` to `1` by default.
 */
int config_with_options(config_fn_t fn, void *,
                        struct git_config_source *config_source,
                        struct repository *repo,
                        const struct config_options *opts);

/**
 * Value Parsing Helpers
 * ---------------------
 *
 * The following helper functions aid in parsing string values
 */

/**
 * Parse the string to an integer, including unit factors. Dies on error;
 * otherwise, returns the parsed result.
 */
int git_config_int(const char *, const char *, const struct key_value_info *);

int64_t git_config_int64(const char *, const char *,
                         const struct key_value_info *);

/**
 * Identical to `git_config_int`, but for unsigned longs.
 */
unsigned long git_config_ulong(const char *, const char *,
                               const struct key_value_info *);

ssize_t git_config_ssize_t(const char *, const char *,
                           const struct key_value_info *);

/**
 * Same as `git_config_bool`, except that integers are returned as-is, and
 * an `is_bool` flag is unset.
 */
int git_config_bool_or_int(const char *, const char *,
                           const struct key_value_info *, int *);

/**
 * Parse a string into a boolean value, respecting keywords like "true" and
 * "false". Integer values are converted into true/false values (when they
 * are non-zero or zero, respectively). Other values cause a die(). If
 * parsing is successful, the return value is the result.
 */
int git_config_bool(const char *, const char *);

/**
 * Allocates and copies the value string into the `dest` parameter; if no
 * string is given, prints an error message and returns -1.
 */
int git_config_string(const char **, const char *, const char *);

/**
 * Similar to `git_config_string`, but expands `~` or `~user` into the
 * user's home directory when found at the beginning of the path.
 */
int git_config_pathname(char **, const char *, const char *);

int git_config_expiry_date(timestamp_t *, const char *, const char *);
int git_config_color(char *, const char *, const char *);
int git_config_set_in_file_gently(const char *, const char *, const char *, const char *);

/**
 * write config values to a specific config file, takes a key/value pair as
 * parameter.
 */
void git_config_set_in_file(const char *, const char *, const char *);

int git_config_set_gently(const char *, const char *);

/**
 * Write a config value that should apply to the current worktree. If
 * extensions.worktreeConfig is enabled, then the write will happen in the
 * current worktree's config. Otherwise, write to the common config file.
 */
int repo_config_set_worktree_gently(struct repository *, const char *, const char *);

/**
 * write config values to `.git/config`, takes a key/value pair as parameter.
 */
void git_config_set(const char *, const char *);

int git_config_parse_key(const char *, char **, size_t *);

/*
 * The following macros specify flag bits that alter the behavior
 * of the git_config_set_multivar*() methods.
 */

/*
 * When CONFIG_FLAGS_MULTI_REPLACE is specified, all matching key/values
 * are removed before a single new pair is written. If the flag is not
 * present, then set operations replace only the first match.
 */
#define CONFIG_FLAGS_MULTI_REPLACE (1 << 0)

/*
 * When CONFIG_FLAGS_FIXED_VALUE is specified, match key/value pairs
 * by string comparison (not regex match) to the provided value_pattern
 * parameter.
 */
#define CONFIG_FLAGS_FIXED_VALUE (1 << 1)

int git_config_set_multivar_gently(const char *, const char *, const char *, unsigned);
void git_config_set_multivar(const char *, const char *, const char *, unsigned);
int repo_config_set_multivar_gently(struct repository *, const char *, const char *, const char *, unsigned);
int git_config_set_multivar_in_file_gently(const char *, const char *, const char *, const char *, const char *, unsigned);

char *git_config_prepare_comment_string(const char *);

/**
 * takes four parameters:
 *
 * - the name of the file, as a string, to which key/value pairs will be written.
 *
 * - the name of key, as a string. This is in canonical "flat" form: the section,
 *   subsection, and variable segments will be separated by dots, and the section
 *   and variable segments will be all lowercase.
 *   E.g., `core.ignorecase`, `diff.SomeType.textconv`.
 *
 * - the value of the variable, as a string. If value is equal to NULL, it will
 *   remove the matching key from the config file.
 *
 * - the value regex, as a string. It will disregard key/value pairs where value
 *   does not match.
 *
 * - a flags value with bits corresponding to the CONFIG_FLAG_* macros.
 *
 * It returns 0 on success.
 */
void git_config_set_multivar_in_file(const char *config_filename,
                                     const char *key,
                                     const char *value,
                                     const char *value_pattern,
                                     unsigned flags);

/**
 * rename or remove sections in the config file
 * parameters `old_name` and `new_name`
 * If NULL is passed through `new_name` parameter,
 * the section will be removed from the config file.
 */
int git_config_rename_section(const char *, const char *);

int git_config_rename_section_in_file(const char *, const char *, const char *);
int git_config_copy_section(const char *, const char *);
int git_config_copy_section_in_file(const char *, const char *, const char *);
int git_config_system(void);
int config_error_nonbool(const char *);
#if defined(__GNUC__)
#define config_error_nonbool(s) (config_error_nonbool(s), const_error())
#endif

char *git_system_config(void);
char *git_global_config(void);
void git_global_config_paths(char **user, char **xdg);

int git_config_parse_parameter(const char *, config_fn_t fn, void *data);

const char *config_origin_type_name(enum config_origin_type type);
void kvi_from_param(struct key_value_info *out);

/*
 * 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).
 *
 * If the subsection pointer-to-pointer passed in is NULL, returns 0 only if
 * there is no subsection at all.
 */
int parse_config_key(const char *var,
                     const char *section,
                     const char **subsection, size_t *subsection_len,
                     const char **key);

/**
 * Custom Configsets
 * -----------------
 *
 * A `config_set` can be used to construct an in-memory cache for
 * config-like files that the caller specifies (i.e., files like `.gitmodules`,
 * `~/.gitconfig` etc.). For example,
 *
 * ----------------------------------------
 * struct config_set gm_config;
 * git_configset_init(&gm_config);
 * int b;
 * //we add config files to the config_set
 * git_configset_add_file(&gm_config, ".gitmodules");
 * git_configset_add_file(&gm_config, ".gitmodules_alt");
 *
 * if (!git_configset_get_bool(gm_config, "submodule.frotz.ignore", &b)) {
 * //hack hack hack
 * }
 *
 * when we are done with the configset:
 * git_configset_clear(&gm_config);
 * ----------------------------------------
 *
 * Configset API provides functions for the above mentioned work flow
 */

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;
};

/**
 * Initializes the config_set `cs`.
 */
void git_configset_init(struct config_set *cs);

/**
 * Parses the file and adds the variable-value pairs to the `config_set`,
 * dies if there is an error in parsing the file. Returns 0 on success, or
 * -1 if the file does not exist or is inaccessible. The caller decides
 * whether to free the incomplete configset or continue using it when
 * the function returns -1.
 */
int git_configset_add_file(struct config_set *cs, const char *filename);

/**
 * Finds and returns the value list, sorted in order of increasing priority
 * for the configuration variable `key` and config set `cs`. When the
 * configuration variable `key` is not found, returns 1 without touching
 * `value`.
 *
 * The key will be parsed for validity with git_config_parse_key(), on
 * error a negative value will be returned.
 *
 * The caller should not free or modify the returned pointer, as it is
 * owned by the cache.
 */
RESULT_MUST_BE_USED
int git_configset_get_value_multi(struct config_set *cs, const char *key,
                                  const struct string_list **dest);

/**
 * A validation wrapper for git_configset_get_value_multi() which does
 * for it what git_configset_get_string() does for
 * git_configset_get_value().
 *
 * The configuration syntax allows for "[section] key", which will
 * give us a NULL entry in the "struct string_list", as opposed to
 * "[section] key =" which is the empty string. Most users of the API
 * are not prepared to handle NULL in a "struct string_list".
 */
int git_configset_get_string_multi(struct config_set *cs, const char *key,
                                   const struct string_list **dest);

/**
 * Clears `config_set` structure, removes all saved variable-value pairs.
 */
void git_configset_clear(struct config_set *cs);

/*
 * These functions return 1 if not found, and 0 if found, leaving the found
 * value in the 'dest' pointer.
 */

/**
 * git_configset_get() returns negative values on error, see
 * repo_config_get() below.
 */
RESULT_MUST_BE_USED
int git_configset_get(struct config_set *cs, const char *key);

/*
 * Finds the highest-priority value for the configuration variable `key`
 * and config set `cs`, stores the pointer to it in `value` and returns 0.
 * When the configuration variable `key` is not found, returns 1 without
 * touching `value`. The caller should not free or modify `value`, as it
 * is owned by the cache.
 */
int git_configset_get_value(struct config_set *cs, const char *key,
                            const char **dest, struct key_value_info *kvi);

int git_configset_get_string(struct config_set *cs, const char *key, char **dest);
int git_configset_get_int(struct config_set *cs, const char *key, int *dest);
int git_configset_get_ulong(struct config_set *cs, const char *key, unsigned long *dest);
int git_configset_get_bool(struct config_set *cs, const char *key, int *dest);
int git_configset_get_bool_or_int(struct config_set *cs, const char *key, int *is_bool, int *dest);
int git_configset_get_maybe_bool(struct config_set *cs, const char *key, int *dest);
int git_configset_get_pathname(struct config_set *cs, const char *key, char **dest);

/* Functions for reading a repository's config */
struct repository;
void repo_config(struct repository *repo, config_fn_t fn, void *data);

/**
 * Run only the discover part of the repo_config_get_*() functions
 * below, in addition to 1 if not found, returns negative values on
 * error (e.g. if the key itself is invalid).
 */
RESULT_MUST_BE_USED
int repo_config_get(struct repository *repo, const char *key);
int repo_config_get_value(struct repository *repo,
                          const char *key, const char **value);
RESULT_MUST_BE_USED
int repo_config_get_value_multi(struct repository *repo, const char *key,
                                const struct string_list **dest);
RESULT_MUST_BE_USED
int repo_config_get_string_multi(struct repository *repo, const char *key,
                                 const struct string_list **dest);
int repo_config_get_string(struct repository *repo,
                           const char *key, char **dest);
int repo_config_get_string_tmp(struct repository *repo,
                               const char *key, const char **dest);
int repo_config_get_int(struct repository *repo,
                        const char *key, int *dest);
int repo_config_get_ulong(struct repository *repo,
                          const char *key, unsigned long *dest);
int repo_config_get_bool(struct repository *repo,
                         const char *key, int *dest);
int repo_config_get_bool_or_int(struct repository *repo,
                                const char *key, int *is_bool, int *dest);
int repo_config_get_maybe_bool(struct repository *repo,
                               const char *key, int *dest);
int repo_config_get_pathname(struct repository *repo,
                             const char *key, char **dest);

/*
 * Functions for reading protected config. By definition, protected
 * config ignores repository config, so these do not take a `struct
 * repository` parameter.
 */
void git_protected_config(config_fn_t fn, void *data);

/**
 * Querying For Specific Variables
 * -------------------------------
 *
 * For programs wanting to query for specific variables in a non-callback
 * manner, the config API provides two functions `git_config_get_value`
 * and `git_config_get_value_multi`. They both read values from an internal
 * cache generated previously from reading the config files.
 *
 * For those git_config_get*() functions that aren't documented,
 * consult the corresponding repo_config_get*() function's
 * documentation.
 */

RESULT_MUST_BE_USED
int git_config_get(const char *key);

/**
 * Finds the highest-priority value for the configuration variable `key`,
 * stores the pointer to it in `value` and returns 0. When the
 * configuration variable `key` is not found, returns 1 without touching
 * `value`. The caller should not free or modify `value`, as it is owned
 * by the cache.
 */
int git_config_get_value(const char *key, const char **value);

/**
 * Finds and returns the value list, sorted in order of increasing priority
 * for the configuration variable `key`. When the configuration variable
 * `key` is not found, returns 1 without touching `value`.
 *
 * The caller should not free or modify the returned pointer, as it is
 * owned by the cache.
 */
RESULT_MUST_BE_USED
int git_config_get_value_multi(const char *key,
                               const struct string_list **dest);
RESULT_MUST_BE_USED
int git_config_get_string_multi(const char *key,
                                const struct string_list **dest);

/**
 * Resets and invalidates the config cache.
 */
void git_config_clear(void);

/**
 * Allocates and copies the retrieved string into the `dest` parameter for
 * the configuration variable `key`; if NULL string is given, prints an
 * error message and returns -1. When the configuration variable `key` is
 * not found, returns 1 without touching `dest`.
 */
int git_config_get_string(const char *key, char **dest);

/**
 * Similar to `git_config_get_string`, but does not allocate any new
 * memory; on success `dest` will point to memory owned by the config
 * machinery, which could be invalidated if it is discarded and reloaded.
 */
int git_config_get_string_tmp(const char *key, const char **dest);

/**
 * Finds and parses the value to an integer for the configuration variable
 * `key`. Dies on error; otherwise, stores the value of the parsed integer in
 * `dest` and returns 0. When the configuration variable `key` is not found,
 * returns 1 without touching `dest`.
 */
int git_config_get_int(const char *key, int *dest);

/**
 * Similar to `git_config_get_int` but for unsigned longs.
 */
int git_config_get_ulong(const char *key, unsigned long *dest);

/**
 * Finds and parses the value into a boolean value, for the configuration
 * variable `key` respecting keywords like "true" and "false". Integer
 * values are converted into true/false values (when they are non-zero or
 * zero, respectively). Other values cause a die(). If parsing is successful,
 * stores the value of the parsed result in `dest` and returns 0. When the
 * configuration variable `key` is not found, returns 1 without touching
 * `dest`.
 */
int git_config_get_bool(const char *key, int *dest);

/**
 * Similar to `git_config_get_bool`, except that integers are copied as-is,
 * and `is_bool` flag is unset.
 */
int git_config_get_bool_or_int(const char *key, int *is_bool, int *dest);

/**
 * Similar to `git_config_get_bool`, except that it returns -1 on error
 * rather than dying.
 */
int git_config_get_maybe_bool(const char *key, int *dest);

/**
 * Similar to `git_config_get_string`, but expands `~` or `~user` into
 * the user's home directory when found at the beginning of the path.
 */
int git_config_get_pathname(const char *key, char **dest);

int git_config_get_index_threads(int *dest);
int git_config_get_split_index(void);
int git_config_get_max_percent_split_change(void);

/* This dies if the configured or default date is in the future */
int git_config_get_expiry(const char *key, const char **output);

/* parse either "this many days" integer, or "5.days.ago" approxidate */
int git_config_get_expiry_in_days(const char *key, timestamp_t *, timestamp_t now);

/**
 * First prints the error message specified by the caller in `err` and then
 * dies printing the line number and the file name of the highest priority
 * value for the configuration variable `key`.
 */
NORETURN void git_die_config(const char *key, const char *err, ...) __attribute__((format(printf, 2, 3)));

/**
 * Helper function which formats the die error message according to the
 * parameters entered. Used by `git_die_config()`. It can be used by callers
 * handling `git_config_get_value_multi()` to print the correct error message
 * for the desired value.
 */
NORETURN void git_die_config_linenr(const char *key, const char *filename, int linenr);

#define LOOKUP_CONFIG(mapping, var) \
        lookup_config(mapping, ARRAY_SIZE(mapping), var)
int lookup_config(const char **mapping, int nr_mapping, const char *var);

#endif /* CONFIG_H */