FT-274 Use ybt functions for descriptor memory management, which is

safer and more readable.

ft/ft-serialize.cc

@@ -153,15 +153,7 @@ deserialize_descriptor_from_rbuf(struct rbuf *rb, DESCRIPTOR desc, int layout_ve
     uint32_t size;
     bytevec data;
     rbuf_bytes(rb, &data, &size);
-    bytevec data_copy = data;
-    if (size > 0) {
-        data_copy = toku_memdup(data, size); //Cannot keep the reference from rbuf. Must copy.
-        lazy_assert(data_copy);
-    } else {
-        lazy_assert(size==0);
-        data_copy = NULL;
-    }
-    toku_fill_dbt(&desc->dbt, data_copy, size);
+    toku_memdup_dbt(&desc->dbt, data, size);
 }
 
 static int
@@ -194,12 +186,10 @@ deserialize_descriptor_from(int fd, BLOCK_TABLE bt, DESCRIPTOR desc, int layout_
                     goto exit;
                 }
             }
-            {
-                struct rbuf rb = {.buf = dbuf, .size = (unsigned int) size, .ndone = 0};
-                //Not temporary; must have a toku_memdup'd copy.
-                deserialize_descriptor_from_rbuf(&rb, desc, layout_version);
-            }
-            lazy_assert(deserialize_descriptor_size(desc, layout_version)+4 == size);
+
+            struct rbuf rb = { .buf = dbuf, .size = (unsigned int) size, .ndone = 0 };
+            deserialize_descriptor_from_rbuf(&rb, desc, layout_version);
+            lazy_assert(deserialize_descriptor_size(desc, layout_version) + 4 == size);
             toku_free(dbuf);
         }
     }
@@ -436,10 +426,10 @@ int deserialize_ft_versioned(int fd, struct rbuf *rb, FT *ftp, uint32_t version)
     if (r != 0) {
         goto exit;
     }
+
     // initialize for svn #4541
-    // TODO: use real dbt function
-    ft->cmp_descriptor.dbt.size = ft->descriptor.dbt.size;
-    ft->cmp_descriptor.dbt.data = toku_xmemdup(ft->descriptor.dbt.data, ft->descriptor.dbt.size);
+    toku_clone_dbt(&ft->cmp_descriptor.dbt, ft->descriptor.dbt);
+
     // Version 13 descriptors had an extra 4 bytes that we don't read
     // anymore.  Since the header is going to think it's the current
     // version if it gets written out, we need to write the descriptor in

ft/ft.cc

@@ -120,10 +120,8 @@ ft_destroy(FT ft) {
     assert(ft->h->type == FT_CURRENT);
     toku_blocktable_destroy(&ft->blocktable);
     ft->cmp.destroy();
-    // TODO: use real dbt function
-    if (ft->descriptor.dbt.data) toku_free(ft->descriptor.dbt.data);
-    // TODO: use real dbt function
-    if (ft->cmp_descriptor.dbt.data) toku_free(ft->cmp_descriptor.dbt.data);
+    toku_destroy_dbt(&ft->descriptor.dbt);
+    toku_destroy_dbt(&ft->cmp_descriptor.dbt);
     toku_ft_destroy_reflock(ft);
     toku_free(ft->h);
 }
@@ -913,26 +911,14 @@ toku_ft_update_descriptor_with_fd(FT ft, DESCRIPTOR desc, int fd) {
     toku_serialize_descriptor_contents_to_fd(fd, desc, offset);
 
     // cleanup the old descriptor and set the in-memory descriptor to the new one
-    // TODO: use real dbt function
-    if (ft->descriptor.dbt.data) {
-        toku_free(ft->descriptor.dbt.data);
-    }
-    // TODO: use real dbt function
-    ft->descriptor.dbt.size = desc->dbt.size;
-    ft->descriptor.dbt.data = toku_memdup(desc->dbt.data, desc->dbt.size);
+    toku_destroy_dbt(&ft->descriptor.dbt);
+    toku_clone_dbt(&ft->descriptor.dbt, desc->dbt);
 }
 
 void toku_ft_update_cmp_descriptor(FT ft) {
-    // TODO: use real dbt function
-    if (ft->cmp_descriptor.dbt.data != NULL) {
-        toku_free(ft->cmp_descriptor.dbt.data);
-    }
-    // TODO: use real dbt function
-    ft->cmp_descriptor.dbt.size = ft->descriptor.dbt.size;
-    ft->cmp_descriptor.dbt.data = toku_xmemdup(
-        ft->descriptor.dbt.data, 
-        ft->descriptor.dbt.size
-        );
+    // cleanup the old cmp descriptor and clone it as the in-memory descriptor
+    toku_destroy_dbt(&ft->cmp_descriptor.dbt);
+    toku_clone_dbt(&ft->cmp_descriptor.dbt, ft->descriptor.dbt);
 }
 
 DESCRIPTOR toku_ft_get_descriptor(FT_HANDLE ft_handle) {

src/ydb_db.cc

@@ -565,11 +565,12 @@ toku_db_change_descriptor(DB *db, DB_TXN* txn, const DBT* descriptor, uint32_t f
     HANDLE_DB_ILLEGAL_WORKING_PARENT_TXN(db, txn);
     int r = 0;
     TOKUTXN ttxn = txn ? db_txn_struct_i(txn)->tokutxn : NULL;
-    DBT old_descriptor;
     bool is_db_hot_index  = ((flags & DB_IS_HOT_INDEX) != 0);
     bool update_cmp_descriptor = ((flags & DB_UPDATE_CMP_DESCRIPTOR) != 0);
 
-    toku_init_dbt(&old_descriptor);
+    DBT old_descriptor_dbt;
+    toku_init_dbt(&old_descriptor_dbt);
+
     if (!db_opened(db) || !descriptor || (descriptor->size>0 && !descriptor->data)){
         r = EINVAL;
         goto cleanup;
@@ -582,23 +583,12 @@ toku_db_change_descriptor(DB *db, DB_TXN* txn, const DBT* descriptor, uint32_t f
         if (r != 0) { goto cleanup; }    
     }
 
-    // TODO: use toku_clone_dbt(&old-descriptor, db->descriptor);
-    old_descriptor.size = db->descriptor->dbt.size;
-    old_descriptor.data = toku_memdup(db->descriptor->dbt.data, db->descriptor->dbt.size);
-
-    toku_ft_change_descriptor(
-        db->i->ft_handle, 
-        &old_descriptor, 
-        descriptor, 
-        true, 
-        ttxn, 
-        update_cmp_descriptor
-        );
+    toku_clone_dbt(&old_descriptor_dbt, db->descriptor->dbt);
+    toku_ft_change_descriptor(db->i->ft_handle, &old_descriptor_dbt, descriptor, 
+                              true, ttxn, update_cmp_descriptor);
 
 cleanup:
-    if (old_descriptor.data) {
-        toku_free(old_descriptor.data);
-    }
+    toku_destroy_dbt(&old_descriptor_dbt);
     return r;
 }