[PATCH 02/13] vinyl: embed index in vy_lsm

[Vladimir Davydov <vdavydov.dev@gmail.com>]

There's no point in having vinyl_engine and vinyl_index wrapper structs
to bind vy_env and vy_lsm to struct engine and index. Instead we can
simply embed engine and index in vy_env and vy_lsm. This will simplify
further development, e.g. this will allow us to move reference counting
from vy_lsm up to struct index so that it can be used in the generic
code.
---
 src/box/vinyl.c  | 39 ++++++++++++---------------------------
 src/box/vy_lsm.h |  3 ++-
 2 files changed, 14 insertions(+), 28 deletions(-)

diff --git a/src/box/vinyl.c b/src/box/vinyl.c
index 327d0c39..645e36ca 100644
--- a/src/box/vinyl.c
+++ b/src/box/vinyl.c
@@ -142,19 +142,6 @@ struct vy_env {
 	bool force_recovery;
 };
 
-struct vinyl_index {
-	struct index base;
-	/** LSM tree that stores index data. */
-	struct vy_lsm *lsm;
-};
-
-/** Extract vy_lsm from an index object. */
-struct vy_lsm *
-vy_lsm(struct index *index)
-{
-	return ((struct vinyl_index *)index)->lsm;
-}
-
 /** Mask passed to vy_gc(). */
 enum {
 	/** Delete incomplete runs. */
@@ -206,6 +193,14 @@ vy_env(struct engine *engine)
 	return (struct vy_env *)engine;
 }
 
+/** Extract vy_lsm from an index object. */
+struct vy_lsm *
+vy_lsm(struct index *index)
+{
+	assert(index->vtab == &vinyl_index_vtab);
+	return (struct vy_lsm *)index;
+}
+
 /**
  * A quick intro into Vinyl cosmology and file format
  * --------------------------------------------------
@@ -688,12 +683,6 @@ static struct index *
 vinyl_space_create_index(struct space *space, struct index_def *index_def)
 {
 	assert(index_def->type == TREE);
-	struct vinyl_index *index = calloc(1, sizeof(*index));
-	if (index == NULL) {
-		diag_set(OutOfMemory, sizeof(*index),
-			 "malloc", "struct vinyl_index");
-		return NULL;
-	}
 	struct vy_env *env = vy_env(space->engine);
 	struct vy_lsm *pk = NULL;
 	if (index_def->iid > 0) {
@@ -703,18 +692,15 @@ vinyl_space_create_index(struct space *space, struct index_def *index_def)
 	struct vy_lsm *lsm = vy_lsm_new(&env->lsm_env, &env->cache_env,
 					&env->mem_env, index_def, space->format,
 					pk, space_group_id(space));
-	if (lsm == NULL) {
-		free(index);
+	if (lsm == NULL)
 		return NULL;
-	}
-	if (index_create(&index->base, &env->base,
+
+	if (index_create(&lsm->base, &env->base,
 			 &vinyl_index_vtab, index_def) != 0) {
 		vy_lsm_delete(lsm);
-		free(index);
 		return NULL;
 	}
-	index->lsm = lsm;
-	return &index->base;
+	return &lsm->base;
 }
 
 static void
@@ -727,7 +713,6 @@ vinyl_index_destroy(struct index *index)
 	 * is gone.
 	 */
 	vy_lsm_unref(lsm);
-	free(index);
 }
 
 /**
diff --git a/src/box/vy_lsm.h b/src/box/vy_lsm.h
index d9e4b582..327a886b 100644
--- a/src/box/vy_lsm.h
+++ b/src/box/vy_lsm.h
@@ -37,6 +37,7 @@
 #include <small/mempool.h>
 #include <small/rlist.h>
 
+#include "index.h"
 #include "index_def.h"
 #define HEAP_FORWARD_DECLARATION
 #include "salad/heap.h"
@@ -51,7 +52,6 @@ extern "C" {
 #endif /* defined(__cplusplus) */
 
 struct histogram;
-struct index;
 struct tuple;
 struct tuple_format;
 struct vy_lsm;
@@ -179,6 +179,7 @@ vy_lsm_env_destroy(struct vy_lsm_env *env);
  *   secondary key, i.e. the tuple stored. This is key_def.
  */
 struct vy_lsm {
+	struct index base;
 	/** Common LSM tree environment. */
 	struct vy_lsm_env *env;
 	/**
-- 
2.20.1