From 3c8687a73eeffc21f5a0b3916d38e46ff985933d Mon Sep 17 00:00:00 2001 From: Tanay Abhra Date: Mon, 28 Jul 2014 03:10:38 -0700 Subject: add `config_set` API for caching config-like files Currently `git_config()` uses a callback mechanism and file rereads for config values. Due to this approach, it is not uncommon for the config files to be parsed several times during the run of a git program, with different callbacks picking out different variables useful to themselves. Add a `config_set`, that can be used to construct an in-memory cache for config-like files that the caller specifies (i.e., files like `.gitmodules`, `~/.gitconfig` etc.). Add two external functions `git_configset_get_value` and `git_configset_get_value_multi` for querying from the config sets. `git_configset_get_value` follows `last one wins` semantic (i.e. if there are multiple matches for the queried key in the files of the configset the value returned will be the last entry in `value_list`). `git_configset_get_value_multi` returns a list of values sorted in order of increasing priority (i.e. last match will be at the end of the list). Add type specific query functions like `git_configset_get_bool` and similar. Add a default `config_set`, `the_config_set` to cache all key-value pairs read from usual config files (repo specific .git/config, user wide ~/.gitconfig, XDG config and the global /etc/gitconfig). `the_config_set` is populated using `git_config()`. Add two external functions `git_config_get_value` and `git_config_get_value_multi` for querying in a non-callback manner from `the_config_set`. Also, add type specific query functions that are implemented as a thin wrapper around the `config_set` API. Signed-off-by: Matthieu Moy Signed-off-by: Tanay Abhra Signed-off-by: Junio C Hamano diff --git a/Documentation/technical/api-config.txt b/Documentation/technical/api-config.txt index 230b3a0..815c1ee 100644 --- a/Documentation/technical/api-config.txt +++ b/Documentation/technical/api-config.txt @@ -77,6 +77,86 @@ 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. + +See test-config.c for usage examples. + Value Parsing Helpers --------------------- @@ -134,6 +214,68 @@ 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 -------------------- diff --git a/cache.h b/cache.h index fcb511d..7292aef 100644 --- a/cache.h +++ b/cache.h @@ -1351,6 +1351,38 @@ extern int parse_config_key(const char *var, const char **subsection, int *subsection_len, const char **key); +struct config_set { + struct hashmap config_hash; + int hash_initialized; +}; + +extern void git_configset_init(struct config_set *cs); +extern int git_configset_add_file(struct config_set *cs, const char *filename); +extern int git_configset_get_value(struct config_set *cs, const char *key, const char **value); +extern const struct string_list *git_configset_get_value_multi(struct config_set *cs, const char *key); +extern void git_configset_clear(struct config_set *cs); +extern int git_configset_get_string_const(struct config_set *cs, const char *key, const char **dest); +extern int git_configset_get_string(struct config_set *cs, const char *key, char **dest); +extern int git_configset_get_int(struct config_set *cs, const char *key, int *dest); +extern int git_configset_get_ulong(struct config_set *cs, const char *key, unsigned long *dest); +extern int git_configset_get_bool(struct config_set *cs, const char *key, int *dest); +extern int git_configset_get_bool_or_int(struct config_set *cs, const char *key, int *is_bool, int *dest); +extern int git_configset_get_maybe_bool(struct config_set *cs, const char *key, int *dest); +extern int git_configset_get_pathname(struct config_set *cs, const char *key, const char **dest); + +extern int git_config_get_value(const char *key, const char **value); +extern const struct string_list *git_config_get_value_multi(const char *key); +extern void git_config_clear(void); +extern void git_config_iter(config_fn_t fn, void *data); +extern int git_config_get_string_const(const char *key, const char **dest); +extern int git_config_get_string(const char *key, char **dest); +extern int git_config_get_int(const char *key, int *dest); +extern int git_config_get_ulong(const char *key, unsigned long *dest); +extern int git_config_get_bool(const char *key, int *dest); +extern int git_config_get_bool_or_int(const char *key, int *is_bool, int *dest); +extern int git_config_get_maybe_bool(const char *key, int *dest); +extern int git_config_get_pathname(const char *key, const char **dest); + extern int committer_ident_sufficiently_given(void); extern int author_ident_sufficiently_given(void); diff --git a/config.c b/config.c index 9767c4b..d3ad661 100644 --- a/config.c +++ b/config.c @@ -9,6 +9,8 @@ #include "exec_cmd.h" #include "strbuf.h" #include "quote.h" +#include "hashmap.h" +#include "string-list.h" struct config_source { struct config_source *prev; @@ -33,10 +35,23 @@ struct config_source { long (*do_ftell)(struct config_source *c); }; +struct config_set_element { + struct hashmap_entry ent; + char *key; + struct string_list value_list; +}; + static struct config_source *cf; static int zlib_compression_seen; +/* + * Default config_set that contains key-value pairs from the usual set of config + * config files (i.e repo specific .git/config, user wide ~/.gitconfig, XDG + * config file and the global /etc/gitconfig) + */ +static struct config_set the_config_set; + static int config_file_fgetc(struct config_source *conf) { return fgetc(conf->u.file); @@ -1212,6 +1227,262 @@ int git_config(config_fn_t fn, void *data) return git_config_with_options(fn, data, NULL, 1); } +static struct config_set_element *configset_find_element(struct config_set *cs, const char *key) +{ + struct config_set_element k; + struct config_set_element *found_entry; + char *normalized_key; + int ret; + /* + * `key` may come from the user, so normalize it before using it + * for querying entries from the hashmap. + */ + ret = git_config_parse_key(key, &normalized_key, NULL); + + if (ret) + return NULL; + + hashmap_entry_init(&k, strhash(normalized_key)); + k.key = normalized_key; + found_entry = hashmap_get(&cs->config_hash, &k, NULL); + free(normalized_key); + return found_entry; +} + +static int configset_add_value(struct config_set *cs, const char *key, const char *value) +{ + struct config_set_element *e; + e = configset_find_element(cs, key); + /* + * Since the keys are being fed by git_config*() callback mechanism, they + * are already normalized. So simply add them without any further munging. + */ + if (!e) { + e = xmalloc(sizeof(*e)); + hashmap_entry_init(e, strhash(key)); + e->key = xstrdup(key); + string_list_init(&e->value_list, 1); + hashmap_add(&cs->config_hash, e); + } + string_list_append_nodup(&e->value_list, value ? xstrdup(value) : NULL); + + return 0; +} + +static int config_set_element_cmp(const struct config_set_element *e1, + const struct config_set_element *e2, const void *unused) +{ + return strcmp(e1->key, e2->key); +} + +void git_configset_init(struct config_set *cs) +{ + hashmap_init(&cs->config_hash, (hashmap_cmp_fn)config_set_element_cmp, 0); + cs->hash_initialized = 1; +} + +void git_configset_clear(struct config_set *cs) +{ + struct config_set_element *entry; + struct hashmap_iter iter; + if (!cs->hash_initialized) + return; + + hashmap_iter_init(&cs->config_hash, &iter); + while ((entry = hashmap_iter_next(&iter))) { + free(entry->key); + string_list_clear(&entry->value_list, 0); + } + hashmap_free(&cs->config_hash, 1); + cs->hash_initialized = 0; +} + +static int config_set_callback(const char *key, const char *value, void *cb) +{ + struct config_set *cs = cb; + configset_add_value(cs, key, value); + return 0; +} + +int git_configset_add_file(struct config_set *cs, const char *filename) +{ + return git_config_from_file(config_set_callback, filename, cs); +} + +int git_configset_get_value(struct config_set *cs, const char *key, const char **value) +{ + const struct string_list *values = NULL; + /* + * Follows "last one wins" semantic, i.e., if there are multiple matches for the + * queried key in the files of the configset, the value returned will be the last + * value in the value list for that key. + */ + values = git_configset_get_value_multi(cs, key); + + if (!values) + return 1; + assert(values->nr > 0); + *value = values->items[values->nr - 1].string; + return 0; +} + +const struct string_list *git_configset_get_value_multi(struct config_set *cs, const char *key) +{ + struct config_set_element *e = configset_find_element(cs, key); + return e ? &e->value_list : NULL; +} + +int git_configset_get_string_const(struct config_set *cs, const char *key, const char **dest) +{ + const char *value; + if (!git_configset_get_value(cs, key, &value)) + return git_config_string(dest, key, value); + else + return 1; +} + +int git_configset_get_string(struct config_set *cs, const char *key, char **dest) +{ + return git_configset_get_string_const(cs, key, (const char **)dest); +} + +int git_configset_get_int(struct config_set *cs, const char *key, int *dest) +{ + const char *value; + if (!git_configset_get_value(cs, key, &value)) { + *dest = git_config_int(key, value); + return 0; + } else + return 1; +} + +int git_configset_get_ulong(struct config_set *cs, const char *key, unsigned long *dest) +{ + const char *value; + if (!git_configset_get_value(cs, key, &value)) { + *dest = git_config_ulong(key, value); + return 0; + } else + return 1; +} + +int git_configset_get_bool(struct config_set *cs, const char *key, int *dest) +{ + const char *value; + if (!git_configset_get_value(cs, key, &value)) { + *dest = git_config_bool(key, value); + return 0; + } else + return 1; +} + +int git_configset_get_bool_or_int(struct config_set *cs, const char *key, + int *is_bool, int *dest) +{ + const char *value; + if (!git_configset_get_value(cs, key, &value)) { + *dest = git_config_bool_or_int(key, value, is_bool); + return 0; + } else + return 1; +} + +int git_configset_get_maybe_bool(struct config_set *cs, const char *key, int *dest) +{ + const char *value; + if (!git_configset_get_value(cs, key, &value)) { + *dest = git_config_maybe_bool(key, value); + if (*dest == -1) + return -1; + return 0; + } else + return 1; +} + +int git_configset_get_pathname(struct config_set *cs, const char *key, const char **dest) +{ + const char *value; + if (!git_configset_get_value(cs, key, &value)) + return git_config_pathname(dest, key, value); + else + return 1; +} + +static void git_config_check_init(void) +{ + if (the_config_set.hash_initialized) + return; + git_configset_init(&the_config_set); + git_config(config_set_callback, &the_config_set); +} + +void git_config_clear(void) +{ + if (!the_config_set.hash_initialized) + return; + git_configset_clear(&the_config_set); +} + +int git_config_get_value(const char *key, const char **value) +{ + git_config_check_init(); + return git_configset_get_value(&the_config_set, key, value); +} + +const struct string_list *git_config_get_value_multi(const char *key) +{ + git_config_check_init(); + return git_configset_get_value_multi(&the_config_set, key); +} + +int git_config_get_string_const(const char *key, const char **dest) +{ + git_config_check_init(); + return git_configset_get_string_const(&the_config_set, key, dest); +} + +int git_config_get_string(const char *key, char **dest) +{ + git_config_check_init(); + return git_config_get_string_const(key, (const char **)dest); +} + +int git_config_get_int(const char *key, int *dest) +{ + git_config_check_init(); + return git_configset_get_int(&the_config_set, key, dest); +} + +int git_config_get_ulong(const char *key, unsigned long *dest) +{ + git_config_check_init(); + return git_configset_get_ulong(&the_config_set, key, dest); +} + +int git_config_get_bool(const char *key, int *dest) +{ + git_config_check_init(); + return git_configset_get_bool(&the_config_set, key, dest); +} + +int git_config_get_bool_or_int(const char *key, int *is_bool, int *dest) +{ + git_config_check_init(); + return git_configset_get_bool_or_int(&the_config_set, key, is_bool, dest); +} + +int git_config_get_maybe_bool(const char *key, int *dest) +{ + git_config_check_init(); + return git_configset_get_maybe_bool(&the_config_set, key, dest); +} + +int git_config_get_pathname(const char *key, const char **dest) +{ + git_config_check_init(); + return git_configset_get_pathname(&the_config_set, key, dest); +} + /* * Find all the stuff for git_config_set() below. */ @@ -1707,6 +1978,9 @@ int git_config_set_multivar_in_file(const char *config_filename, lock = NULL; ret = 0; + /* Invalidate the config cache */ + git_config_clear(); + out_free: if (lock) rollback_lock_file(lock); diff --git a/setup.c b/setup.c index 0a22f8b..793369d 100644 --- a/setup.c +++ b/setup.c @@ -625,6 +625,15 @@ static const char *setup_git_directory_gently_1(int *nongit_ok) int one_filesystem = 1; /* + * We may have read an incomplete configuration before + * setting-up the git directory. If so, clear the cache so + * that the next queries to the configuration reload complete + * configuration (including the per-repo config file that we + * ignored previously). + */ + git_config_clear(); + + /* * Let's assume that we are in a git repository. * If it turns out later that we are somewhere else, the value will be * updated accordingly. -- cgit v0.10.2-6-g49f6