[tarantool-patches] [PATCH 6/7] Always store built-in collations in the cache

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

To be able to use collations out of box.cfg it is needed to be
sure, that they are available always. Else it can break non-box
collation usage. So when a built-in collation is deleted from
_collation (for example, on box.internal.bootstrap()), it is not
deleted from the cache. When a built-in collation is inserted
into _collation, it does not touch the cache (it already contains
all built-in collations).
---
 src/box/alter.cc | 14 ++++++++++++++
 src/coll_cache.c | 34 ++++++++++++++++++++++++++++++++++
 src/coll_def.c   |  7 +++++++
 src/coll_def.h   | 13 +++++++++++++
 4 files changed, 68 insertions(+)

diff --git a/src/box/alter.cc b/src/box/alter.cc
index be2ccc061..39fcc8de4 100644
--- a/src/box/alter.cc
+++ b/src/box/alter.cc
@@ -2429,6 +2429,13 @@ on_replace_dd_collation(struct trigger * /* trigger */, void *event)
 		/* TODO: Check that no index uses the collation */
 		int32_t old_id = tuple_field_u32_xc(old_tuple,
 						    BOX_COLLATION_FIELD_ID);
+		if (coll_is_system(old_id)) {
+			/*
+			 * Built-in collations can be deleted from
+			 * _collation, but not from the cache.
+			 */
+			return;
+		}
 		struct coll *old_coll = coll_by_id(old_id);
 		assert(old_coll != NULL);
 		access_check_ddl(old_coll->name, old_coll->owner_id,
@@ -2451,6 +2458,13 @@ on_replace_dd_collation(struct trigger * /* trigger */, void *event)
 		coll_def_new_from_tuple(new_tuple, &new_def);
 		access_check_ddl(new_def.name, new_def.owner_id, SC_COLLATION,
 				 PRIV_C, false);
+		if (coll_is_system(new_def.id)) {
+			/*
+			 * Built-in collation is in the cache
+			 * already.
+			 */
+			return;
+		}
 		/*
 		 * Set on_rollback before the collation is
 		 * inserted into the cache. Else if the trigger
diff --git a/src/coll_cache.c b/src/coll_cache.c
index b7eb3edb9..b7fce5aba 100644
--- a/src/coll_cache.c
+++ b/src/coll_cache.c
@@ -45,7 +45,41 @@ coll_cache_init()
 			 "coll_cache_id");
 		return -1;
 	}
+	struct coll *replaced, *unicode_coll, *unicode_ci_coll;
+	struct coll_def def;
+	memset(&def, 0, sizeof(def));
+	def.id = COLLATION_ID_UNICODE;
+	def.owner_id = 1;
+	def.name = "unicode";
+	def.name_len = strlen(def.name);
+	def.locale = "";
+	def.type = COLL_TYPE_ICU;
+	unicode_coll = coll_new(&def);
+	if (unicode_coll == NULL)
+		goto err_unicode;
+	if (coll_cache_replace(unicode_coll, &replaced) != 0)
+		goto err_unicode_replace;
+	assert(replaced == NULL);
+
+	def.id = COLLATION_ID_UNICODE_CI;
+	def.name = "unicode_ci";
+	def.name_len = strlen(def.name);
+	def.icu.strength = COLL_ICU_STRENGTH_PRIMARY;
+	unicode_ci_coll = coll_new(&def);
+	if (unicode_ci_coll == NULL)
+		goto err_unicode_ci;
+	if (coll_cache_replace(unicode_ci_coll, &replaced) != 0)
+		goto err_unicode_ci_replace;
 	return 0;
+err_unicode_ci_replace:
+	coll_delete(unicode_ci_coll);
+err_unicode_ci:
+	coll_cache_delete(unicode_coll);
+err_unicode_replace:
+	coll_delete(unicode_coll);
+err_unicode:
+	mh_i32ptr_delete(coll_cache_id);
+	return -1;
 }
 
 /** Delete global hash tables. */
diff --git a/src/coll_def.c b/src/coll_def.c
index f849845b3..0a0ead9a1 100644
--- a/src/coll_def.c
+++ b/src/coll_def.c
@@ -63,6 +63,13 @@ const char *coll_icu_strength_strs[] = {
 	"IDENTICAL"
 };
 
+bool
+coll_is_system(int coll_id)
+{
+	return coll_id == COLLATION_ID_UNICODE ||
+	       coll_id == COLLATION_ID_UNICODE_CI;
+}
+
 static int64_t
 icu_on_off_from_str(const char *str, uint32_t len)
 {
diff --git a/src/coll_def.h b/src/coll_def.h
index 7a1027a1e..e86c546e5 100644
--- a/src/coll_def.h
+++ b/src/coll_def.h
@@ -49,6 +49,19 @@ enum coll_type {
 
 extern const char *coll_type_strs[];
 
+/** Built-in collations. */
+enum {
+	COLLATION_ID_UNICODE = 1,
+	COLLATION_ID_UNICODE_CI = 2,
+};
+
+/**
+ * Check if a collation is system by its ID. System collations can
+ * not be deleted.
+ */
+bool
+coll_is_system(int coll_id);
+
 /*
  * ICU collation options. See
  * http://icu-project.org/apiref/icu4c/ucol_8h.html#a583fbe7fc4a850e2fcc692e766d2826c
-- 
2.15.1 (Apple Git-101)