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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 <Matthieu.Moy@imag.fr>
Signed-off-by: Tanay Abhra <tanayabh@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Tanay Abhra 2014-07-28 03:10:38 -07:00 committed by Junio C Hamano
parent 996b0fdbb4
commit 3c8687a73e
4 changed files with 457 additions and 0 deletions
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142
Documentation/technical/api-config.txt
View File

@ -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
--------------------

32
cache.h
View File

@ -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);

274
config.c
View File

@ -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);

9
setup.c
View File

@ -624,6 +624,15 @@ static const char *setup_git_directory_gently_1(int *nongit_ok)
dev_t current_device = 0;
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