Add a hash table to cache all key-value pairs read from config files
(repo specific .git/config, user wide ~/.gitconfig and the global
/etc/gitconfig). Add two external functions `git_config_get_string` and
`git_config_get_string_multi` for querying in a non-callback manner from the
hash table.
Add a way to construct custom config sets which contain multiple config
files cached as hashmaps for value retrieval.
---
*NOTE*
Please ignore the commit message and the documentation. This is a WIP. This patch
implements the user facing API which was discussed thoroughly in discussion thread[1].
A more polished patch will land next week, this patch is just to give a feel for what
I inferred from the discussion.
API functions:
1. int git_config_get_value(char *k, char **v): The most generic function, traverses
the usual config functions for values. (internally uses the the_config_set struct)
2. int git_configset_get_value_from(const char *key, const char **value,
const char *filename, struct config_set *cs)
For usage of this function, see the example given below.
Most of the extra API functions will be constructed on the top of this patch.
Workflow for custom config_set works like this,
char *value;
struct config_set gm_config = {NULL, 0 ,0};
git_configset_add_file(".gitmodule", &gm_config);
/* Add other files similarly */
git_configset_get_value_from(key, &value, ".gitmodule", &gm_config);
/* Work on config values free the set when done */
git_configset_clear(&gm_config);
I have tested the workflow and it works fine. :)
Now, about helper functions, if I add new helper functions for get_ family like
git_config_get_string, git_config_get_int and similar, won't the helper functions
in config.c would become redundant. Is it really necessary to write new
helper functions for the non-callback code, instead of reusing the older ones?
[1]: http://marc.info/?t=140351850200001&r=1&w=2
Cheers,
Tanay Abhra.
Documentation/technical/api-config.txt | 26 +++++
cache.h | 2 +
config.c | 182 +++++++++++++++++++++++++++++++++
3 files changed, 210 insertions(+)
diff --git a/Documentation/technical/api-config.txt b/Documentation/technical/api-config.txt
index 230b3a0..13f3f40 100644
--- a/Documentation/technical/api-config.txt
+++ b/Documentation/technical/api-config.txt
@@ -77,6 +77,32 @@ 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_string`
+and `git_config_get_string_multi`.They both read values from an internal
+cache generated previously from reading the config files.
+
+`git_config_get_string` takes two parameters,
+
+- a key string in canonical flat form for which the corresponding value
+ with the highest priority (i.e. value in the repo config will be
+ preferred over value in user wide config for the same variable) will
+ be retrieved.
+
+- a pointer to a string which will point to the retrieved value.
+
+`git_config_get_string` returns 0 for success, or -1 for no value found.
+
+`git_config_get_string_multi` returns a `string_list` containing all the
+values for the key passed as parameter, sorted in order of increasing
+priority (Note: NULL values are flagged as 1, check `util` for each
+'string_list_item` for flag value).
+
+See test-config.c for usage examples.
+
Value Parsing Helpers
---------------------
diff --git a/cache.h b/cache.h
index cbe1935..fec0a63 100644
--- a/cache.h
+++ b/cache.h
@@ -1294,6 +1294,8 @@ extern int check_repository_format_version(const char *var, const char *value, v
extern int git_env_bool(const char *, int);
extern int git_config_system(void);
extern int config_error_nonbool(const char *);
+extern int git_config_get_string(const char *, const char **);
+extern const struct string_list *git_config_get_string_multi(const char *);
#if defined(__GNUC__)
#define config_error_nonbool(s) (config_error_nonbool(s), const_error())
#endif
diff --git a/config.c b/config.c
index a1aef1c..332d92e 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;
@@ -37,6 +39,180 @@ static struct config_source *cf;
static int zlib_compression_seen;
+struct config_hash_entry {
+ struct hashmap_entry ent;
+ char *key;
+ struct string_list value_list;
+};
+
+struct config_set {
+ struct config_set_item *item;
+ unsigned int nr, alloc;
+};
+
+struct config_set_item {
+ struct hashmap config_hash;
+ char *filename;
+ int hashmap_initialized;
+};
+
+static struct config_set_cb {
+ struct config_set *cs;
+ struct config_set_item *ct;
+};
+
+static struct config_set the_config_set;
+
+static int config_hash_add_value(const char *, const char *,
+ struct config_set_item *, struct config_set *);
+
+static int config_hash_entry_cmp(const struct config_hash_entry *e1,
+ const struct config_hash_entry *e2, const void *unused)
+{
+ return strcmp(e1->key, e2->key);
+}
+
+static void config_hash_init(struct hashmap *config_hash)
+{
+ hashmap_init(config_hash, (hashmap_cmp_fn)config_hash_entry_cmp, 0);
+}
+
+static int config_hash_callback(const char *key, const char *value, void *cb)
+{
+ struct config_set_cb *c = cb;
+ config_hash_add_value(key, value, c->ct, c->cs);
+ return 0;
+}
+
+static struct hashmap *get_config_hash(const char *filename, struct config_set *cs)
+{
+ int i;
+ struct config_set_item *ct;
+ struct config_set_cb cb;
+ for(i = 0; i < cs->nr; i++) {
+ if (!strcmp(cs->item[i].filename, filename))
+ return &cs->item[i].config_hash;
+ }
+
+ ALLOC_GROW(cs->item, cs->nr + 1, cs->alloc);
+ ct = &cs->item[cs->nr++];
+ ct->filename = xstrdup(filename);
+ config_hash_init(&ct->config_hash);
+ ct->hashmap_initialized = 1;
+ cb.cs = cs;
+ cb.ct = ct;
+ /*
+ * When filename is "default", hashmap is constructed from the usual set of
+ * config files (i.e repo specific .git/config, user wide ~/.gitconfig and the
+ * global /etc/gitconfig)
+ */
+ if (!strcmp(filename, "default"))
+ git_config(config_hash_callback, &cb);
+ else
+ git_config_from_file(config_hash_callback, filename, &cb);
+
+ return &ct->config_hash;
+}
+
+static struct config_hash_entry *config_hash_find_entry(const char *key, const char* filename,
+ struct config_set *cs)
+{
+ struct hashmap *config_hash;
+ struct config_hash_entry k;
+ struct config_hash_entry *found_entry;
+ char *normalized_key;
+ int ret;
+ config_hash = get_config_hash(filename, cs);
+ 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(config_hash, &k, NULL);
+ free(normalized_key);
+ return found_entry;
+}
+
+static struct string_list *config_hash_get_value(const char *key, const char* filename,
+ struct config_set *cs)
+{
+ struct config_hash_entry *e = config_hash_find_entry(key, filename, cs);
+ return e ? &e->value_list : NULL;
+}
+
+static int config_hash_add_value(const char *key, const char *value,
+ struct config_set_item *ct, struct config_set *cs)
+{
+ struct hashmap *config_hash = &ct->config_hash;
+ struct config_hash_entry *e;
+ e = config_hash_find_entry(key, ct->filename, cs);
+
+ if (!e) {
+ e = xmalloc(sizeof(*e));
+ hashmap_entry_init(e, strhash(key));
+ e->key = xstrdup(key);
+ string_list_init_dup(&e->value_list);
+ hashmap_add(config_hash, e);
+ }
+ string_list_append_nodup(&e->value_list, value ? xstrdup(value) : NULL);
+
+ return 0;
+}
+
+int git_configset_get_value_from(const char *key, const char **value,
+ const char *filename, struct config_set *cs)
+{
+ struct string_list *values;
+ values = config_hash_get_value(key, filename, cs);
+ if (!values)
+ return -1;
+ assert(values->nr > 0);
+ *value = values->items[values->nr - 1].string;
+ return 0;
+}
+
+int git_config_get_value(const char *key, const char **value)
+{
+ return git_configset_get_value_from(key, value, "default", &the_config_set);
+}
+
+const struct string_list *git_config_get_value_multi(const char *key)
+{
+ return config_hash_get_value(key, "default", &the_config_set);
+}
+
+const struct string_list *git_configset_get_value_multi_from(const char *key, const char* filename,
+ struct config_set *cs)
+{
+ return config_hash_get_value(key, filename, cs);
+}
+
+void git_configset_add_file(char *filename, struct config_set *cs)
+{
+ get_config_hash(filename, cs);
+}
+
+void git_configset_clear(struct config_set *cs)
+{
+ int i;
+ struct hashmap *config_hash;
+ struct config_hash_entry *entry;
+ struct hashmap_iter iter;
+ for (i = 0; i < cs->nr; i++) {
+ config_hash = &cs->item[i].config_hash;
+ free(cs->item[i].filename);
+ cs->item[i].hashmap_initialized = 0;
+ hashmap_iter_init(config_hash, &iter);
+ while ((entry = hashmap_iter_next(&iter))) {
+ free(entry->key);
+ string_list_clear(&entry->value_list, 0);
+ }
+ hashmap_free(config_hash, 1);
+ }
+}
+
static int config_file_fgetc(struct config_source *conf)
{
return fgetc(conf->u.file);
@@ -1708,6 +1884,12 @@ int git_config_set_multivar_in_file(const char *config_filename,
lock = NULL;
ret = 0;
+ /*
+ * content of config file has changed, so invalidate the
+ * config cache used by non-callback based query functions.
+ */
+ git_configset_clear(&the_config_set);
+
out_free:
if (lock)
rollback_lock_file(lock);
--
1.9.0.GIT
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