box: introduce index layout option

It is intended to be used by `memcs` engine to specify the layout options.

Needed for tarantool/tarantool-ee#1089

NO_DOC=will be done EE
NO_CHANGELOG=does not work with CE engines

Author: Gumix

src/box/index_def.c

@@ -54,6 +54,7 @@ const struct index_opts index_opts_default = {
 	/* .hint                = */ INDEX_HINT_DEFAULT,
 	/* .covered_fields      = */ NULL,
 	/* .covered_field_count = */ 0,
+	/* .layout              = */ NULL,
 };
 
 /**
@@ -113,6 +114,24 @@ index_opts_parse_covered_fields(const char **data, void *opts,
 	return 0;
 }
 
+/** Parse index layout option given as MsgPack in `data' into `opts'. */
+static int
+index_opts_parse_layout(const char **data, void *opts, struct region *region)
+{
+	struct index_opts *index_opts = (struct index_opts *)opts;
+	if (mp_typeof(**data) != MP_STR) {
+		diag_set(IllegalParams, "'layout' must be string");
+		return -1;
+	}
+	uint32_t len = 0;
+	const char *str = mp_decode_str(data, &len);
+	if (len > 0) {
+		index_opts->layout = xregion_alloc(region, len + 1);
+		strlcpy(index_opts->layout, str, len + 1);
+	}
+	return 0;
+}
+
 const struct opt_def index_opts_reg[] = {
 	OPT_DEF("unique", OPT_BOOL, struct index_opts, is_unique),
 	OPT_DEF("dimension", OPT_INT64, struct index_opts, dimension),
@@ -128,6 +147,7 @@ const struct opt_def index_opts_reg[] = {
 	OPT_DEF_LEGACY("sql"),
 	OPT_DEF_CUSTOM("hint", index_opts_parse_hint),
 	OPT_DEF_CUSTOM("covers", index_opts_parse_covered_fields),
+	OPT_DEF_CUSTOM("layout", index_opts_parse_layout),
 	OPT_END,
 };
 
@@ -144,6 +164,9 @@ const struct opt_def index_opts_reg[] = {
 static void
 index_opts_normalize(struct index_opts *opts, const struct key_def *cmp_def)
 {
+	if (opts->layout != NULL)
+		opts->layout = xstrdup(opts->layout);
+
 	if (opts->covered_field_count == 0)
 		return;
 	uint32_t *fields = xmalloc(sizeof(*fields) * opts->covered_field_count);
@@ -213,6 +236,8 @@ index_opts_dup(const struct index_opts *opts, struct index_opts *dup)
 		       dup->covered_field_count *
 		       sizeof(*dup->covered_fields));
 	}
+	if (dup->layout != NULL)
+		dup->layout = xstrdup(dup->layout);
 }
 
 struct index_def *
@@ -235,7 +260,6 @@ index_def_dup(const struct index_def *def)
 void
 index_def_delete(struct index_def *index_def)
 {
-	free(index_def->opts.covered_fields);
 	index_opts_destroy(&index_def->opts);
 	free(index_def->name);
 	free(index_def->space_name);

src/box/index_def.h

@@ -120,6 +120,11 @@ struct index_opts {
 	 * Number of covered fields.
 	 */
 	uint32_t covered_field_count;
+	/**
+	 * Engine dependent. For engines supporting various layouts means a
+	 * string with the layout options.
+	 */
+	char *layout;
 };
 
 extern const struct index_opts index_opts_default;
@@ -140,6 +145,8 @@ index_opts_create(struct index_opts *opts)
 static inline void
 index_opts_destroy(struct index_opts *opts)
 {
+	free(opts->covered_fields);
+	free(opts->layout);
 	TRASH(opts);
 }
 
@@ -172,6 +179,12 @@ index_opts_is_equal(const struct index_opts *o1, const struct index_opts *o2)
 		if (o1->covered_fields[i] != o2->covered_fields[i])
 			return false;
 	}
+	if (o1->layout != NULL && o2->layout != NULL) {
+		if (strcmp(o1->layout, o2->layout) != 0)
+			return false;
+	} else if (o1->layout != NULL || o2->layout != NULL) {
+		return false;
+	}
 	return true;
 }
 

src/box/lua/schema.lua

@@ -1571,6 +1571,7 @@ local index_options = {
     func = 'number, string',
     hint = 'boolean',
     covers = 'table',
+    layout = 'string',
 }
 
 local function jsonpaths_from_idx_parts(parts)
@@ -1746,6 +1747,7 @@ box.schema.index.create = atomic_wrapper(function(space_id, name, options)
             func = options.func,
             hint = options.hint,
             covers = options.covers,
+            layout = options.layout,
     }
     local field_type_aliases = {
         num = 'unsigned'; -- Deprecated since 1.7.2

src/box/lua/space.cc

@@ -639,6 +639,11 @@ lbox_fillspace(struct lua_State *L, struct space *space, int i)
 			lua_setfield(L, -2, "covers");
 		}
 
+		if (index_def->opts.layout != NULL) {
+			lua_pushstring(L, index_def->opts.layout);
+			lua_setfield(L, -2, "layout");
+		}
+
 		lua_pushstring(L, "sequence_id");
 		if (k == 0 && space->sequence != NULL) {
 			lua_pushnumber(L, space->sequence->def->id);

src/box/memtx_space.c

@@ -883,6 +883,11 @@ memtx_space_check_index_def(struct space *space, struct index_def *index_def)
 			 "covering index");
 		return -1;
 	}
+	if (index_def->opts.layout != NULL) {
+		diag_set(ClientError, ER_UNSUPPORTED, "memtx",
+			 "'layout' option");
+		return -1;
+	}
 	return 0;
 }
 

src/box/vinyl.c

@@ -699,6 +699,11 @@ vinyl_space_check_index_def(struct space *space, struct index_def *index_def)
 			 "covering index");
 		return -1;
 	}
+	if (index_def->opts.layout != NULL) {
+		diag_set(ClientError, ER_UNSUPPORTED, "vinyl",
+			 "'layout' option");
+		return -1;
+	}
 	return 0;
 }
 

test/box-luatest/index_layout_test.lua

@@ -0,0 +1,59 @@
+local server = require('luatest.server')
+local t = require('luatest')
+
+local g = t.group()
+
+g.before_all(function(cg)
+    cg.server = server:new()
+    cg.server:start()
+end)
+
+g.after_all(function(cg)
+    cg.server:drop()
+end)
+
+g.after_each(function(cg)
+    cg.server:exec(function()
+        if box.space.test ~= nil then
+            box.space.test:drop()
+        end
+    end)
+end)
+
+g.test_arg_check = function(cg)
+    cg.server:exec(function()
+        local s = box.schema.space.create('test')
+        t.assert_error_covers({
+            type = 'IllegalParams',
+            name = 'ILLEGAL_PARAMS',
+            message = "options parameter 'layout' should be of type string",
+        }, s.create_index, s, 'pk', {layout = 1234})
+
+        t.assert_error_covers({
+            type = 'ClientError',
+            name = 'WRONG_INDEX_OPTIONS',
+            message = "Wrong index options: 'layout' must be string",
+        }, box.space._index.insert, box.space._index, {
+            s.id, 0, 'pk', 'tree', {layout = 1234}, {{[0] = 'unsigned'}}
+        })
+    end)
+end
+
+g.test_unsupported = function(cg)
+    cg.server:exec(function()
+        local s = box.schema.space.create('test', {engine = 'memtx'})
+        t.assert_error_covers({
+            type = 'ClientError',
+            name = 'UNSUPPORTED',
+            message = "memtx does not support 'layout' option",
+        }, s.create_index, s, 'pk', {layout = 'test'})
+        s:drop()
+
+        s = box.schema.space.create('test', {engine = 'vinyl'})
+        t.assert_error_covers({
+            type = 'ClientError',
+            name = 'UNSUPPORTED',
+            message = "vinyl does not support 'layout' option",
+        }, s.create_index, s, 'pk', {layout = 'test'})
+    end)
+end