config.c: remove current_config_kvi

Add ".config_kvi" to "struct config_reader" and replace
"current_config_kvi" with "the_reader.config_kvi", plumbing "struct
config_reader" where necesssary.

Also, introduce a setter function for ".config_kvi", which allows us to
enforce the contraint that only one of ".source" and ".config_kvi" can
be set at a time (as documented in the comments). Because of this
constraint, we know that "populate_remote_urls()" was never touching
"current_config_kvi" when iterating through config files, so it doesn't
need to store and restore that value.

Signed-off-by: Glen Choo <chooglen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

config.c

@@ -52,7 +52,24 @@ struct config_source {
 #define CONFIG_SOURCE_INIT { 0 }
 
 struct config_reader {
+	/*
+	 * These members record the "current" config source, which can be
+	 * accessed by parsing callbacks.
+	 *
+	 * The "source" variable will be non-NULL only when we are actually
+	 * parsing a real config source (file, blob, cmdline, etc).
+	 *
+	 * The "config_kvi" variable will be non-NULL only when we are feeding
+	 * cached config from a configset into a callback.
+	 *
+	 * They cannot be non-NULL at the same time. If they are both NULL, then
+	 * we aren't parsing anything (and depending on the function looking at
+	 * the variables, it's either a bug for it to be called in the first
+	 * place, or it's a function which can be reused for non-config
+	 * purposes, and should fall back to some sane behavior).
+	 */
 	struct config_source *source;
+	struct key_value_info *config_kvi;
 };
 /*
  * Where possible, prefer to accept "struct config_reader" as an arg than to use
@@ -61,27 +78,6 @@ struct config_reader {
  */
 static struct config_reader the_reader;
 
-/*
- * FIXME The comments are temporarily out of date since "cf_global" has been
- * moved to the_reader, but not current_*.
- *
- * These variables record the "current" config source, which
- * can be accessed by parsing callbacks.
- *
- * The "cf_global" variable will be non-NULL only when we are actually
- * parsing a real config source (file, blob, cmdline, etc).
- *
- * The "current_config_kvi" variable will be non-NULL only when we are feeding
- * cached config from a configset into a callback.
- *
- * They should generally never be non-NULL at the same time. If they are both
- * NULL, then we aren't parsing anything (and depending on the function looking
- * at the variables, it's either a bug for it to be called in the first place,
- * or it's a function which can be reused for non-config purposes, and should
- * fall back to some sane behavior).
- */
-static struct key_value_info *current_config_kvi;
-
 /*
  * Similar to the variables above, this gives access to the "scope" of the
  * current value (repo, global, etc). For cached values, it can be found via
@@ -95,6 +91,8 @@ static enum config_scope current_parsing_scope;
 static inline void config_reader_push_source(struct config_reader *reader,
 					     struct config_source *top)
 {
+	if (reader->config_kvi)
+		BUG("source should not be set while iterating a config set");
 	top->prev = reader->source;
 	reader->source = top;
 }
@@ -109,6 +107,14 @@ static inline struct config_source *config_reader_pop_source(struct config_reade
 	return ret;
 }
 
+static inline void config_reader_set_kvi(struct config_reader *reader,
+					 struct key_value_info *kvi)
+{
+	if (kvi && reader->source)
+		BUG("kvi should not be set while parsing a config source");
+	reader->config_kvi = kvi;
+}
+
 static int pack_compression_seen;
 static int zlib_compression_seen;
 
@@ -377,20 +383,17 @@ static void populate_remote_urls(struct config_include_data *inc)
 {
 	struct config_options opts;
 
-	struct key_value_info *store_kvi = current_config_kvi;
 	enum config_scope store_scope = current_parsing_scope;
 
 	opts = *inc->opts;
 	opts.unconditional_remote_url = 1;
 
-	current_config_kvi = NULL;
 	current_parsing_scope = 0;
 
 	inc->remote_urls = xmalloc(sizeof(*inc->remote_urls));
 	string_list_init_dup(inc->remote_urls);
 	config_with_options(add_remote_url, inc->remote_urls, inc->config_source, &opts);
 
-	current_config_kvi = store_kvi;
 	current_parsing_scope = store_scope;
 }
 
@@ -2257,7 +2260,8 @@ int config_with_options(config_fn_t fn, void *data,
 	return ret;
 }
 
-static void configset_iter(struct config_set *cs, config_fn_t fn, void *data)
+static void configset_iter(struct config_reader *reader, struct config_set *cs,
+			   config_fn_t fn, void *data)
 {
 	int i, value_index;
 	struct string_list *values;
@@ -2269,14 +2273,14 @@ static void configset_iter(struct config_set *cs, config_fn_t fn, void *data)
 		value_index = list->items[i].value_index;
 		values = &entry->value_list;
 
-		current_config_kvi = values->items[value_index].util;
+		config_reader_set_kvi(reader, values->items[value_index].util);
 
 		if (fn(entry->key, values->items[value_index].string, data) < 0)
 			git_die_config_linenr(entry->key,
-					      current_config_kvi->filename,
-					      current_config_kvi->linenr);
+					      reader->config_kvi->filename,
+					      reader->config_kvi->linenr);
 
-		current_config_kvi = NULL;
+		config_reader_set_kvi(reader, NULL);
 	}
 }
 
@@ -2614,7 +2618,7 @@ static void repo_config_clear(struct repository *repo)
 void repo_config(struct repository *repo, config_fn_t fn, void *data)
 {
 	git_config_check_init(repo);
-	configset_iter(repo->config, fn, data);
+	configset_iter(&the_reader, repo->config, fn, data);
 }
 
 int repo_config_get_value(struct repository *repo,
@@ -2720,7 +2724,7 @@ void git_protected_config(config_fn_t fn, void *data)
 {
 	if (!protected_config.hash_initialized)
 		read_protected_config();
-	configset_iter(&protected_config, fn, data);
+	configset_iter(&the_reader, &protected_config, fn, data);
 }
 
 /* Functions used historically to read configuration from 'the_repository' */
@@ -3827,8 +3831,8 @@ int parse_config_key(const char *var,
 const char *current_config_origin_type(void)
 {
 	int type;
-	if (current_config_kvi)
-		type = current_config_kvi->origin_type;
+	if (the_reader.config_kvi)
+		type = the_reader.config_kvi->origin_type;
 	else if(the_reader.source)
 		type = the_reader.source->origin_type;
 	else
@@ -3873,8 +3877,8 @@ const char *config_scope_name(enum config_scope scope)
 const char *current_config_name(void)
 {
 	const char *name;
-	if (current_config_kvi)
-		name = current_config_kvi->filename;
+	if (the_reader.config_kvi)
+		name = the_reader.config_kvi->filename;
 	else if (the_reader.source)
 		name = the_reader.source->name;
 	else
@@ -3884,16 +3888,16 @@ const char *current_config_name(void)
 
 enum config_scope current_config_scope(void)
 {
-	if (current_config_kvi)
-		return current_config_kvi->scope;
+	if (the_reader.config_kvi)
+		return the_reader.config_kvi->scope;
 	else
 		return current_parsing_scope;
 }
 
 int current_config_line(void)
 {
-	if (current_config_kvi)
-		return current_config_kvi->linenr;
+	if (the_reader.config_kvi)
+		return the_reader.config_kvi->linenr;
 	else
 		return the_reader.source->linenr;
 }