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Diffstat (limited to 'Documentation/technical/api-config.txt')
| -rw-r--r-- | Documentation/technical/api-config.txt | 186 |
1 files changed, 185 insertions, 1 deletions
diff --git a/Documentation/technical/api-config.txt b/Documentation/technical/api-config.txt index 230b3a0..0d8b99b 100644 --- a/Documentation/technical/api-config.txt +++ b/Documentation/technical/api-config.txt @@ -77,6 +77,99 @@ To read a specific file in git-config format, use `git_config_from_file`. This takes the same callback and data parameters as `git_config`. +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. + +`int git_config_get_value(const char *key, const char **value)`:: + + 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. + +`const struct string_list *git_config_get_value_multi(const char *key)`:: + + 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 NULL. The caller should not free or modify + the returned pointer, as it is owned by the cache. + +`void git_config_clear(void)`:: + + Resets and invalidates the config cache. + +The config API also provides type specific API functions which do conversion +as well as retrieval for the queried variable, including: + +`int git_config_get_int(const char *key, int *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_ulong(const char *key, unsigned long *dest)`:: + + Similar to `git_config_get_int` but for unsigned longs. + +`int git_config_get_bool(const char *key, int *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_or_int(const char *key, int *is_bool, 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_maybe_bool(const char *key, int *dest)`:: + + Similar to `git_config_get_bool`, except that it returns -1 on error + rather than dying. + +`int git_config_get_string_const(const char *key, const char **dest)`:: + + 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_const`, except that retrieved value + copied into the `dest` parameter is a mutable string. + +`int git_config_get_pathname(const char *key, const char **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. + +`git_die_config(const char *key, const char *err, ...)`:: + + 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`. + +`void git_die_config_linenr(const char *key, const char *filename, int linenr)`:: + + 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. + +See test-config.c for usage examples. + Value Parsing Helpers --------------------- @@ -134,7 +227,98 @@ int read_file_with_include(const char *file, config_fn_t fn, void *data) `git_config` respects includes automatically. The lower-level `git_config_from_file` does not. +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, including: + +`void git_configset_init(struct config_set *cs)`:: + + Initializes the config_set `cs`. + +`int git_configset_add_file(struct config_set *cs, const char *filename)`:: + + 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 user has to decide + if he wants to free the incomplete configset or continue using it when + the function returns -1. + +`int git_configset_get_value(struct config_set *cs, const char *key, const char **value)`:: + + 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. + +`const struct string_list *git_configset_get_value_multi(struct config_set *cs, const char *key)`:: + + 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 NULL. The caller + should not free or modify the returned pointer, as it is owned by the cache. + +`void git_configset_clear(struct config_set *cs)`:: + + Clears `config_set` structure, removes all saved variable-value pairs. + +In addition to above functions, the `config_set` API provides type specific +functions in the vein of `git_config_get_int` and family but with an extra +parameter, pointer to struct `config_set`. +They all behave similarly to the `git_config_get*()` family described in +"Querying For Specific Variables" above. + Writing Config Files -------------------- -TODO +Git gives multiple entry points in the Config API to write config values to +files namely `git_config_set_in_file` and `git_config_set`, which write to +a specific config file or to `.git/config` respectively. They both take a +key/value pair as parameter. +In the end they both call `git_config_set_multivar_in_file` which 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 multi_replace value, as an int. If value is equal to zero, nothing or only + one matching key/value is replaced, else all matching key/values (regardless + how many) are removed, before the new pair is written. + +It returns 0 on success. + +Also, there are functions `git_config_rename_section` and +`git_config_rename_section_in_file` with parameters `old_name` and `new_name` +for renaming or removing sections in the config files. If NULL is passed +through `new_name` parameter, the section will be removed from the config file. |