| config API |
| ========== |
| |
| The config API gives callers a way to access Git configuration files |
| (and files which have the same syntax). See linkgit:git-config[1] for a |
| discussion of the config file 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. |
| |
| A config callback function takes three 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). |
| |
| - 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. |
| |
| Basic Config Querying |
| --------------------- |
| |
| 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). |
| |
| The `git_config_with_options` function 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: |
| |
| `filename`:: |
| If this parameter is non-NULL, it specifies the name of a file to |
| parse for configuration, rather than looking in the usual files. Regular |
| `git_config` defaults to `NULL`. |
| |
| `respect_includes`:: |
| Specify whether include directives should be followed in parsed files. |
| Regular `git_config` defaults to `1`. |
| |
| There is a special version of `git_config` called `git_config_early`. |
| This version takes an additional parameter to specify the repository |
| config, instead of having it looked up via `git_path`. This is useful |
| early in a Git program before the repository has been found. Unless |
| you're working with early setup code, you probably don't want to use |
| this. |
| |
| Reading Specific Files |
| ---------------------- |
| |
| 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 |
| --------------------- |
| |
| To aid in parsing string values, the config API provides callbacks with |
| a number of helper functions, including: |
| |
| `git_config_int`:: |
| Parse the string to an integer, including unit factors. Dies on error; |
| otherwise, returns the parsed result. |
| |
| `git_config_ulong`:: |
| Identical to `git_config_int`, but for unsigned longs. |
| |
| `git_config_bool`:: |
| 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. |
| |
| `git_config_bool_or_int`:: |
| Same as `git_config_bool`, except that integers are returned as-is, and |
| an `is_bool` flag is unset. |
| |
| `git_config_maybe_bool`:: |
| Same as `git_config_bool`, except that it returns -1 on error rather |
| than dying. |
| |
| `git_config_string`:: |
| Allocates and copies the value string into the `dest` parameter; if no |
| string is given, prints an error message and returns -1. |
| |
| `git_config_pathname`:: |
| Similar to `git_config_string`, but expands `~` or `~user` into the |
| user's home directory when found at the beginning of the path. |
| |
| Include Directives |
| ------------------ |
| |
| By default, the config parser does not respect include directives. |
| However, a caller can use the special `git_config_include` wrapper |
| callback to support them. To do so, you simply wrap your "real" callback |
| function and data pointer in a `struct config_include_data`, and pass |
| the wrapper to the regular config-reading functions. For example: |
| |
| ------------------------------------------- |
| int read_file_with_include(const char *file, config_fn_t fn, void *data) |
| { |
| struct config_include_data inc = CONFIG_INCLUDE_INIT; |
| inc.fn = fn; |
| inc.data = data; |
| return git_config_from_file(git_config_include, file, &inc); |
| } |
| ------------------------------------------- |
| |
| `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 |
| -------------------- |
| |
| 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. |