Merge pull request #72 from mmzeeman/cleanup-connection-and-statement-types

Cleanup connection and statement types

c_src/esqlite3_nif.c

@@ -310,14 +310,17 @@ update_callback(void *arg, int sqlite_operation_type, char const *sqlite_databas
 }
 
 static ERL_NIF_TERM
-do_set_update_hook(ErlNifEnv *env, esqlite_connection *db, const ERL_NIF_TERM arg)
+do_set_update_hook(ErlNifEnv *env, esqlite_connection *conn, const ERL_NIF_TERM arg)
 {
-    if(!enif_get_local_pid(env, arg, &db->notification_pid))
-	    return make_error_tuple(env, "invalid_pid");
+    if(!enif_get_local_pid(env, arg, &conn->notification_pid)) {
+        return make_error_tuple(env, "invalid_pid");
+    }
 
-    sqlite3_update_hook(db->db, NULL, NULL);
-    if(sqlite3_update_hook(db->db, update_callback, db) != SQLITE_OK)
-        return make_error_tuple(env, "sqlite3_update_hook_fail");
+    if(!conn->db) {
+        return make_error_tuple(env, "closed");
+    }
+
+    sqlite3_update_hook(conn->db, update_callback, conn);
 
     return make_atom(env, "ok");
 }
@@ -331,12 +334,11 @@ do_exec(ErlNifEnv *env, esqlite_connection *conn, const ERL_NIF_TERM arg)
     int rc;
     ERL_NIF_TERM eos = enif_make_int(env, 0);
 
-    enif_inspect_iolist_as_binary(env,
-        enif_make_list2(env, arg, eos), &bin);
+    enif_inspect_iolist_as_binary(env, enif_make_list2(env, arg, eos), &bin);
 
     rc = sqlite3_exec(conn->db, (char *) bin.data, NULL, NULL, NULL);
     if(rc != SQLITE_OK)
-	    return make_sqlite3_error_tuple(env, rc, conn->db);
+        return make_sqlite3_error_tuple(env, rc, conn->db);
 
     return make_atom(env, "ok");
 }
@@ -347,6 +349,10 @@ do_exec(ErlNifEnv *env, esqlite_connection *conn, const ERL_NIF_TERM arg)
 static ERL_NIF_TERM
 do_changes(ErlNifEnv *env, esqlite_connection *conn, const ERL_NIF_TERM arg)
 {
+    if(!conn->db) {
+        return make_error_tuple(env, "closed");
+    }
+
     int changes = sqlite3_changes(conn->db);
 
     ERL_NIF_TERM changes_term = enif_make_int64(env, changes);
@@ -374,15 +380,24 @@ do_insert(ErlNifEnv *env, esqlite_connection *conn, const ERL_NIF_TERM arg)
     return make_ok_tuple(env, last_rowid_term);
 }
 
+/*
+ * Return the last inserted rowid
+ */
 static ERL_NIF_TERM
 do_last_insert_rowid(ErlNifEnv *env, esqlite_connection *conn)
 {
+    if(!conn->db) {
+        return make_error_tuple(env, "closed");
+    }
+
     sqlite3_int64 last_rowid = sqlite3_last_insert_rowid(conn->db);
     ERL_NIF_TERM last_rowid_term = enif_make_int64(env, last_rowid);
+
     return make_ok_tuple(env, last_rowid_term);
 }
 
 /*
+ * Compile a sql statement
  */
 static ERL_NIF_TERM
 do_prepare(ErlNifEnv *env, esqlite_connection *conn, const ERL_NIF_TERM arg)
@@ -503,11 +518,15 @@ do_bind(ErlNifEnv *env, sqlite3 *db, sqlite3_stmt *stmt, const ERL_NIF_TERM arg)
 static ERL_NIF_TERM
 do_get_autocommit(ErlNifEnv *env, esqlite_connection *conn)
 {
+    if(!conn->db) {
+        return make_error_tuple(env, "closed");
+    }
+
     if(sqlite3_get_autocommit(conn->db) != 0) {
         return make_atom(env, "true");
-    } else {
-        return make_atom(env, "false");
-    }
+    } 
+
+    return make_atom(env, "false");
 }
 
 static ERL_NIF_TERM
@@ -517,8 +536,8 @@ make_binary(ErlNifEnv *env, const void *bytes, unsigned int size)
     ERL_NIF_TERM term;
 
     if(!enif_alloc_binary(size, &blob)) {
-	    /* TODO: fix this */
-	    return make_atom(env, "error");
+        /* TODO: fix this */
+        return make_atom(env, "error");
     }
 
     memcpy(blob.data, bytes, size);
@@ -534,21 +553,21 @@ make_cell(ErlNifEnv *env, sqlite3_stmt *statement, unsigned int i)
     int type = sqlite3_column_type(statement, i);
 
     switch(type) {
-    case SQLITE_INTEGER:
-	    return enif_make_int64(env, sqlite3_column_int64(statement, i));
-    case SQLITE_FLOAT:
-	    return enif_make_double(env, sqlite3_column_double(statement, i));
-    case SQLITE_BLOB:
-        return enif_make_tuple2(env, make_atom(env, "blob"),
-            make_binary(env, sqlite3_column_blob(statement, i),
-                sqlite3_column_bytes(statement, i)));
-    case SQLITE_NULL:
-	    return make_atom(env, "undefined");
-    case SQLITE_TEXT:
-	    return make_binary(env, sqlite3_column_text(statement, i),
-            sqlite3_column_bytes(statement, i));
-    default:
-	    return make_atom(env, "should_not_happen");
+        case SQLITE_INTEGER:
+            return enif_make_int64(env, sqlite3_column_int64(statement, i));
+        case SQLITE_FLOAT:
+            return enif_make_double(env, sqlite3_column_double(statement, i));
+        case SQLITE_BLOB:
+            return enif_make_tuple2(env, make_atom(env, "blob"),
+                    make_binary(env, sqlite3_column_blob(statement, i),
+                        sqlite3_column_bytes(statement, i)));
+        case SQLITE_NULL:
+            return make_atom(env, "undefined");
+        case SQLITE_TEXT:
+            return make_binary(env, sqlite3_column_text(statement, i),
+                    sqlite3_column_bytes(statement, i));
+        default:
+            return make_atom(env, "should_not_happen");
     }
 }
 
@@ -590,25 +609,25 @@ do_multi_step(ErlNifEnv *env, sqlite3 *db, sqlite3_stmt *stmt, const ERL_NIF_TER
     }
 
     switch(rc) {
-    case SQLITE_ROW:
-        status = make_atom(env, "rows");
-        break;
-    case SQLITE_BUSY:
-        status = make_atom(env, "$busy");
-        break;
-    case SQLITE_DONE:
-        /*
-        * Automatically reset the statement after a done so
-        * column_names will work after the statement is done.
-        *
-        * Not resetting the statement can lead to vm crashes.
-        */
-        sqlite3_reset(stmt);
-        status = make_atom(env, "$done");
-        break;
-    default:
-        /* We use prepare_v2, so any error code can be returned. */
-        return make_sqlite3_error_tuple(env, rc, db);
+        case SQLITE_ROW:
+            status = make_atom(env, "rows");
+            break;
+        case SQLITE_BUSY:
+            status = make_atom(env, "$busy");
+            break;
+        case SQLITE_DONE:
+            /*
+             * Automatically reset the statement after a done so
+             * column_names will work after the statement is done.
+             *
+             * Not resetting the statement can lead to vm crashes.
+             */
+            sqlite3_reset(stmt);
+            status = make_atom(env, "$done");
+            break;
+        default:
+            /* We use prepare_v2, so any error code can be returned. */
+            return make_sqlite3_error_tuple(env, rc, db);
     }
 
     enif_free(rowBuffer);
@@ -698,7 +717,7 @@ do_close(ErlNifEnv *env, esqlite_connection *conn, const ERL_NIF_TERM arg)
 
     rc = sqlite3_close_v2(conn->db);
     if(rc != SQLITE_OK)
-	    return make_sqlite3_error_tuple(env, rc, conn->db);
+        return make_sqlite3_error_tuple(env, rc, conn->db);
 
     conn->db = NULL;
     return make_atom(env, "ok");
@@ -716,36 +735,36 @@ evaluate_command(esqlite_command *cmd, esqlite_connection *conn)
     }
 
     switch(cmd->type) {
-    case cmd_open:
-	    return do_open(cmd->env, conn, cmd->arg);
-    case cmd_update_hook_set:
-        return do_set_update_hook(cmd->env, conn, cmd->arg);
-    case cmd_exec:
-	    return do_exec(cmd->env, conn, cmd->arg);
-    case cmd_changes:
-	    return do_changes(cmd->env, conn, cmd->arg);
-    case cmd_prepare:
-	    return do_prepare(cmd->env, conn, cmd->arg);
-    case cmd_multi_step:
-        return do_multi_step(cmd->env, conn->db, stmt->statement, cmd->arg);
-    case cmd_reset:
-	    return do_reset(cmd->env, conn->db, stmt->statement);
-    case cmd_bind:
-	    return do_bind(cmd->env, conn->db, stmt->statement, cmd->arg);
-    case cmd_column_names:
-	    return do_column_names(cmd->env, stmt->statement);
-    case cmd_column_types:
-	    return do_column_types(cmd->env, stmt->statement);
-    case cmd_close:
-	    return do_close(cmd->env, conn, cmd->arg);
-	case cmd_insert:
-	    return do_insert(cmd->env, conn, cmd->arg);
-    case cmd_last_insert_rowid:
-        return do_last_insert_rowid(cmd->env, conn);
-    case cmd_get_autocommit:
-        return do_get_autocommit(cmd->env, conn);
-    default:
-	    return make_error_tuple(cmd->env, "invalid_command");
+        case cmd_open:
+            return do_open(cmd->env, conn, cmd->arg);
+        case cmd_update_hook_set:
+            return do_set_update_hook(cmd->env, conn, cmd->arg);
+        case cmd_exec:
+            return do_exec(cmd->env, conn, cmd->arg);
+        case cmd_changes:
+            return do_changes(cmd->env, conn, cmd->arg);
+        case cmd_prepare:
+            return do_prepare(cmd->env, conn, cmd->arg);
+        case cmd_multi_step:
+            return do_multi_step(cmd->env, conn->db, stmt->statement, cmd->arg);
+        case cmd_reset:
+            return do_reset(cmd->env, conn->db, stmt->statement);
+        case cmd_bind:
+            return do_bind(cmd->env, conn->db, stmt->statement, cmd->arg);
+        case cmd_column_names:
+            return do_column_names(cmd->env, stmt->statement);
+        case cmd_column_types:
+            return do_column_types(cmd->env, stmt->statement);
+        case cmd_close:
+            return do_close(cmd->env, conn, cmd->arg);
+        case cmd_last_insert_rowid:
+            return do_last_insert_rowid(cmd->env, conn);
+        case cmd_insert:
+            return do_insert(cmd->env, conn, cmd->arg);
+        case cmd_get_autocommit:
+            return do_get_autocommit(cmd->env, conn);
+        default:
+            return make_error_tuple(cmd->env, "invalid_command");
     }
 }
 
@@ -771,17 +790,17 @@ esqlite_connection_run(void *arg)
     int continue_running = 1;
 
     while(continue_running) {
-	    cmd = queue_pop(db->commands);
+        cmd = queue_pop(db->commands);
 
-	    if(cmd->type == cmd_stop) {
-	        continue_running = 0;
+        if(cmd->type == cmd_stop) {
+            continue_running = 0;
         } else if(cmd->type == cmd_notification) {
             enif_send(NULL, &db->notification_pid, cmd->env, cmd->arg);
         } else {
-	        enif_send(NULL, &cmd->pid, cmd->env, make_answer(cmd, evaluate_command(cmd, db)));
+            enif_send(NULL, &cmd->pid, cmd->env, make_answer(cmd, evaluate_command(cmd, db)));
         }
 
-	    command_destroy(cmd);
+        command_destroy(cmd);
     }
 
     return NULL;
@@ -799,22 +818,22 @@ esqlite_start(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
     /* Initialize the resource */
     conn = enif_alloc_resource(esqlite_connection_type, sizeof(esqlite_connection));
     if(!conn)
-	    return make_error_tuple(env, "no_memory");
+        return make_error_tuple(env, "no_memory");
 
     conn->db = NULL;
 
     /* Create command queue */
     conn->commands = queue_create();
     if(!conn->commands) {
-	    enif_release_resource(conn);
-	    return make_error_tuple(env, "command_queue_create_failed");
+        enif_release_resource(conn);
+        return make_error_tuple(env, "command_queue_create_failed");
     }
 
     /* Start command processing thread */
     conn->opts = enif_thread_opts_create("esqldb_thread_opts");
     if(enif_thread_create("esqlite_connection", &conn->tid, esqlite_connection_run, conn, conn->opts) != 0) {
-	    enif_release_resource(conn);
-	    return make_error_tuple(env, "thread_create_failed");
+        enif_release_resource(conn);
+        return make_error_tuple(env, "thread_create_failed");
     }
 
     db_conn = enif_make_resource(env, conn);
@@ -834,21 +853,21 @@ esqlite_open(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
     ErlNifPid pid;
 
     if(argc != 4)
-	    return enif_make_badarg(env);
+        return enif_make_badarg(env);
     if(!enif_get_resource(env, argv[0], esqlite_connection_type, (void **) &db))
-	    return enif_make_badarg(env);
+        return enif_make_badarg(env);
     if(!enif_is_ref(env, argv[1]))
-	    return make_error_tuple(env, "invalid_ref");
+        return make_error_tuple(env, "invalid_ref");
     if(!enif_get_local_pid(env, argv[2], &pid))
-	    return make_error_tuple(env, "invalid_pid");
+        return make_error_tuple(env, "invalid_pid");
 
     if(!sqlite3_threadsafe())
-	    return make_error_tuple(env, "sqlite3 not thread safe.");
+        return make_error_tuple(env, "sqlite3 not thread safe.");
 
     /* Note, no check is made for the type of the argument */
     cmd = command_create();
     if(!cmd)
-	    return make_error_tuple(env, "command_create_failed");
+        return make_error_tuple(env, "command_create_failed");
 
     cmd->type = cmd_open;
     cmd->ref = enif_make_copy(cmd->env, argv[1]);
@@ -866,17 +885,17 @@ set_update_hook(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
     ErlNifPid pid;
 
     if(argc != 4)
-	    return enif_make_badarg(env);
+        return enif_make_badarg(env);
     if(!enif_get_resource(env, argv[0], esqlite_connection_type, (void **) &db))
-	    return enif_make_badarg(env);
+        return enif_make_badarg(env);
     if(!enif_is_ref(env, argv[1]))
-	    return make_error_tuple(env, "invalid_ref");
+        return make_error_tuple(env, "invalid_ref");
     if(!enif_get_local_pid(env, argv[2], &pid))
-	    return make_error_tuple(env, "invalid_pid");
+        return make_error_tuple(env, "invalid_pid");
 
     cmd = command_create();
     if(!cmd)
-	    return make_error_tuple(env, "command_create_failed");
+        return make_error_tuple(env, "command_create_failed");
 
     /* command */
     cmd->type = cmd_update_hook_set;
@@ -1046,17 +1065,17 @@ esqlite_prepare(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
     ErlNifPid pid;
 
     if(argc != 4)
-	    return enif_make_badarg(env);
+        return enif_make_badarg(env);
     if(!enif_get_resource(env, argv[0], esqlite_connection_type, (void **) &conn))
-	    return enif_make_badarg(env);
+        return enif_make_badarg(env);
     if(!enif_is_ref(env, argv[1]))
-	    return make_error_tuple(env, "invalid_ref");
+        return make_error_tuple(env, "invalid_ref");
     if(!enif_get_local_pid(env, argv[2], &pid))
-	    return make_error_tuple(env, "invalid_pid");
+        return make_error_tuple(env, "invalid_pid");
 
     cmd = command_create();
     if(!cmd)
-	    return make_error_tuple(env, "command_create_failed");
+        return make_error_tuple(env, "command_create_failed");
 
     cmd->type = cmd_prepare;
     cmd->ref = enif_make_copy(cmd->env, argv[1]);
@@ -1078,20 +1097,20 @@ esqlite_bind(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
     ErlNifPid pid;
 
     if(argc != 5)
-	    return enif_make_badarg(env);
+        return enif_make_badarg(env);
 
     if(!enif_get_resource(env, argv[0], esqlite_connection_type, (void **) &conn))
-	    return enif_make_badarg(env);
+        return enif_make_badarg(env);
     if(!enif_get_resource(env, argv[1], esqlite_statement_type, (void **) &stmt))
-	    return enif_make_badarg(env);
+        return enif_make_badarg(env);
     if(!enif_is_ref(env, argv[2]))
-	    return make_error_tuple(env, "invalid_ref");
+        return make_error_tuple(env, "invalid_ref");
     if(!enif_get_local_pid(env, argv[3], &pid))
-	    return make_error_tuple(env, "invalid_pid");
+        return make_error_tuple(env, "invalid_pid");
 
     cmd = command_create();
     if(!cmd)
-	    return make_error_tuple(env, "command_create_failed");
+        return make_error_tuple(env, "command_create_failed");
 
     cmd->type = cmd_bind;
     cmd->ref = enif_make_copy(cmd->env, argv[2]);
@@ -1160,21 +1179,21 @@ esqlite_reset(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
     ErlNifPid pid;
 
     if(argc != 4)
-	    return enif_make_badarg(env);
+        return enif_make_badarg(env);
     if(!enif_get_resource(env, argv[0], esqlite_connection_type, (void **) &conn))
-	    return enif_make_badarg(env);
+        return enif_make_badarg(env);
     if(!enif_get_resource(env, argv[1], esqlite_statement_type, (void **) &stmt))
-	    return enif_make_badarg(env);
+        return enif_make_badarg(env);
     if(!enif_is_ref(env, argv[2]))
-	    return make_error_tuple(env, "invalid_ref");
+        return make_error_tuple(env, "invalid_ref");
     if(!enif_get_local_pid(env, argv[3], &pid))
-	    return make_error_tuple(env, "invalid_pid");
+        return make_error_tuple(env, "invalid_pid");
     if(!stmt->statement)
-	    return make_error_tuple(env, "no_prepared_statement");
+        return make_error_tuple(env, "no_prepared_statement");
 
     cmd = command_create();
     if(!cmd)
-	   return make_error_tuple(env, "command_create_failed");
+        return make_error_tuple(env, "command_create_failed");
 
     cmd->type = cmd_reset;
     cmd->ref = enif_make_copy(cmd->env, argv[2]);
@@ -1196,21 +1215,21 @@ esqlite_column_names(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
     ErlNifPid pid;
 
     if(argc != 4)
-	    return enif_make_badarg(env);
+        return enif_make_badarg(env);
     if(!enif_get_resource(env, argv[0], esqlite_connection_type, (void **) &conn))
-	    return enif_make_badarg(env);
+        return enif_make_badarg(env);
     if(!enif_get_resource(env, argv[1], esqlite_statement_type, (void **) &stmt))
-	    return enif_make_badarg(env);
+        return enif_make_badarg(env);
     if(!enif_is_ref(env, argv[2]))
-	    return make_error_tuple(env, "invalid_ref");
+        return make_error_tuple(env, "invalid_ref");
     if(!enif_get_local_pid(env, argv[3], &pid))
-	    return make_error_tuple(env, "invalid_pid");
+        return make_error_tuple(env, "invalid_pid");
     if(!stmt->statement)
-	    return make_error_tuple(env, "no_prepared_statement");
+        return make_error_tuple(env, "no_prepared_statement");
 
     cmd = command_create();
     if(!cmd)
-	    return make_error_tuple(env, "command_create_failed");
+        return make_error_tuple(env, "command_create_failed");
 
     cmd->type = cmd_column_names;
     cmd->ref = enif_make_copy(cmd->env, argv[2]);
@@ -1235,20 +1254,20 @@ esqlite_column_types(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 	    return enif_make_badarg(env);
 
     if(!enif_get_resource(env, argv[0], esqlite_connection_type, (void **) &conn))
-	    return enif_make_badarg(env);
+        return enif_make_badarg(env);
     if(!enif_get_resource(env, argv[1], esqlite_statement_type, (void **) &stmt))
-	    return enif_make_badarg(env);
+        return enif_make_badarg(env);
     if(!enif_is_ref(env, argv[2]))
-	    return make_error_tuple(env, "invalid_ref");
+        return make_error_tuple(env, "invalid_ref");
     if(!enif_get_local_pid(env, argv[3], &pid))
-	    return make_error_tuple(env, "invalid_pid");
+        return make_error_tuple(env, "invalid_pid");
 
     if(!stmt->statement)
-	    return make_error_tuple(env, "no_prepared_statement");
+        return make_error_tuple(env, "no_prepared_statement");
 
     cmd = command_create();
     if(!cmd)
-	    return make_error_tuple(env, "command_create_failed");
+        return make_error_tuple(env, "command_create_failed");
 
     cmd->type = cmd_column_types;
     cmd->ref = enif_make_copy(cmd->env, argv[2]);
@@ -1287,15 +1306,15 @@ esqlite_close(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
     ErlNifPid pid;
 
     if(!enif_get_resource(env, argv[0], esqlite_connection_type, (void **) &conn))
-	    return enif_make_badarg(env);
+        return enif_make_badarg(env);
     if(!enif_is_ref(env, argv[1]))
-	    return make_error_tuple(env, "invalid_ref");
+        return make_error_tuple(env, "invalid_ref");
     if(!enif_get_local_pid(env, argv[2], &pid))
-	    return make_error_tuple(env, "invalid_pid");
+        return make_error_tuple(env, "invalid_pid");
 
     cmd = command_create();
     if(!cmd)
-	    return make_error_tuple(env, "command_create_failed");
+        return make_error_tuple(env, "command_create_failed");
 
     cmd->type = cmd_close;
     cmd->ref = enif_make_copy(cmd->env, argv[1]);
@@ -1313,15 +1332,15 @@ on_load(ErlNifEnv* env, void** priv, ERL_NIF_TERM info)
     ErlNifResourceType *rt;
 
     rt = enif_open_resource_type(env, "esqlite3_nif", "esqlite_connection_type",
-				destruct_esqlite_connection, ERL_NIF_RT_CREATE, NULL);
+            destruct_esqlite_connection, ERL_NIF_RT_CREATE, NULL);
     if(!rt)
-	    return -1;
+        return -1;
     esqlite_connection_type = rt;
 
     rt =  enif_open_resource_type(env, "esqlite3_nif", "esqlite_statement_type",
-				   destruct_esqlite_statement, ERL_NIF_RT_CREATE, NULL);
+            destruct_esqlite_statement, ERL_NIF_RT_CREATE, NULL);
     if(!rt)
-	    return -1;
+        return -1;
     esqlite_statement_type = rt;
 
     atom_esqlite3 = make_atom(env, "esqlite3");

rebar.config.script

@@ -24,6 +24,9 @@ CFlags =
 
 [
     {require_min_otp_vsn, "21"},
+
+    {xref_checks, [undefined_function_calls]},
+
     {port_env, [
         %% Default darwin ldflags causes loading of system sqlite. Removed -bundle flag.
         {"darwin", "DRV_LDFLAGS",
@@ -46,5 +49,14 @@ CFlags =
     {provider_hooks,
         [{post,
         [{compile, {pc, compile}},
-            {clean, {pc, clean}}]}]}
+            {clean, {pc, clean}}]}]},
+
+    {dialyzer, [
+        {warnings, [
+            unmatched_returns,
+            error_handling,
+            race_conditions
+            % underspecs
+        ]}
+    ]}
 ].

src/esqlite3.erl

@@ -50,8 +50,17 @@
 
 %%
 
--type connection() :: {connection, reference(), term()}.
--type statement() :: {statement, term(), connection()}.
+-record(connection, {
+          raw_connection :: esqlite_nif:raw_connection()
+}).
+
+-record(statement, {
+          raw_statement :: esqlite_nif:raw_statement(),
+          raw_connection :: esqlite_nif:raw_connection()
+}).
+
+-type connection() :: #connection{}. 
+-type statement() :: #statement{}.
 -type sql() :: iodata().
 
 %% erlang -> sqlite type conversions
@@ -93,13 +102,13 @@ open(Filename) ->
 %%
 -spec open(string(), timeout()) -> {ok, connection()} | {error, _}.
 open(Filename, Timeout) ->
-    {ok, Connection} = esqlite3_nif:start(),
+    {ok, RawConnection} = esqlite3_nif:start(),
 
     Ref = make_ref(),
-    ok = esqlite3_nif:open(Connection, Ref, self(), Filename),
-    case receive_answer(Connection, Ref, Timeout) of
+    ok = esqlite3_nif:open(RawConnection, Ref, self(), Filename),
+    case receive_answer(RawConnection, Ref, Timeout) of
         ok ->
-            {ok, {connection, make_ref(), Connection}};
+            {ok, #connection{raw_connection=RawConnection}};
         {error, _Msg}=Error ->
             Error
     end.
@@ -119,10 +128,10 @@ set_update_hook(Pid, Connection) ->
 
 %% @doc Same as set_update_hook, but with an additional timeout parameter.
 -spec set_update_hook(pid(), connection(), timeout()) -> ok | {error, term()}.
-set_update_hook(Pid, {connection, _Ref, Connection}, Timeout) ->
+set_update_hook(Pid, #connection{raw_connection=RawConnection}, Timeout) ->
     Ref = make_ref(),
-    ok = esqlite3_nif:set_update_hook(Connection, Ref, self(), Pid),
-    receive_answer(Connection, Ref, Timeout).
+    ok = esqlite3_nif:set_update_hook(RawConnection, Ref, self(), Pid),
+    receive_answer(RawConnection, Ref, Timeout).
 
 %% @doc Execute a sql statement, returns a list with tuples.
 -spec q(sql(), connection()) -> list(tuple()) | {error, term()}.
@@ -341,20 +350,24 @@ exec(Sql, Connection) ->
     exec(Sql, [], Connection, ?DEFAULT_TIMEOUT).
 
 -spec exec(sql(), list(cell_type()) | connection(), connection() | timeout()) -> ok | {error, _}.
-exec(Sql, {connection, _,_}=Connection, Timeout) ->
+exec(Sql, #connection{}=Connection, Timeout) ->
     exec(Sql, [], Connection, Timeout);
-exec(Sql, Params, Connection) ->
+exec(Sql, Params, #connection{}=Connection) ->
     exec(Sql, Params, Connection, ?DEFAULT_TIMEOUT).
 
 -spec exec(sql(), list(cell_type()), connection(), timeout()) -> ok | {error, _}.
-exec(Sql, [], {connection, _Ref, Connection}, Timeout) ->
+exec(Sql, [], #connection{raw_connection=RawConnection}, Timeout) ->
     Ref = make_ref(),
-    ok = esqlite3_nif:exec(Connection, Ref, self(), Sql),
-    receive_answer(Connection, Ref, Timeout);
+    ok = esqlite3_nif:exec(RawConnection, Ref, self(), Sql),
+    receive_answer(RawConnection, Ref, Timeout);
 exec(Sql, Params, Connection, Timeout) ->
     {ok, Statement} = prepare(Sql, Connection, Timeout),
-    bind(Statement, Params),
-    step(Statement, Timeout).
+    case bind(Statement, Params) of
+        ok ->
+            step(Statement, Timeout);
+        {error, _}=Error ->
+            Error
+    end.
 
 
 %% @doc Return the number of affected rows of last statement.
@@ -363,10 +376,10 @@ changes(Connection) ->
     changes(Connection, ?DEFAULT_TIMEOUT).
 
 -spec changes(connection(), timeout()) -> non_neg_integer().
-changes({connection, _Ref, Connection}, Timeout) ->
+changes(#connection{raw_connection=RawConnection}, Timeout) ->
     Ref = make_ref(),
-    ok = esqlite3_nif:changes(Connection, Ref, self()),
-    receive_answer(Connection, Ref, Timeout).
+    ok = esqlite3_nif:changes(RawConnection, Ref, self()),
+    receive_answer(RawConnection, Ref, Timeout).
 
 %% @doc Insert records, returns the last rowid.
 %%
@@ -376,10 +389,10 @@ insert(Sql, Connection) ->
 
 %% @doc Like insert/2, but with extra timeout parameter.
 -spec insert(sql(), connection(), timeout()) -> {ok, rowid()} |  {error, _}.
-insert(Sql, {connection, _Ref, Connection}, Timeout) ->
+insert(Sql, #connection{raw_connection=RawConnection}, Timeout) ->
     Ref = make_ref(),
-    ok = esqlite3_nif:insert(Connection, Ref, self(), Sql),
-    receive_answer(Connection, Ref, Timeout).
+    ok = esqlite3_nif:insert(RawConnection, Ref, self(), Sql),
+    receive_answer(RawConnection, Ref, Timeout).
 
 %% @doc Get the last insert rowid, using the default timeout.
 %%
@@ -389,11 +402,11 @@ last_insert_rowid(Connection) ->
 
 %% @doc Get the last insert rowid.
 %%
--spec last_insert_rowid(connection(), timeout()) -> {ok, integer()} | {error, _}.
-last_insert_rowid({connection, _Ref, Connection}, Timeout) ->
+-spec last_insert_rowid(connection(), timeout()) -> {ok, rowid()} | {error, _}.
+last_insert_rowid(#connection{raw_connection=RawConnection}, Timeout) ->
     Ref = make_ref(),
-    ok = esqlite3_nif:last_insert_rowid(Connection, Ref, self()),
-    receive_answer(Connection, Ref, Timeout).
+    ok = esqlite3_nif:last_insert_rowid(RawConnection, Ref, self()),
+    receive_answer(RawConnection, Ref, Timeout).
 
 %% @doc Get autocommit
 %% @doc Check if the connection is in auto-commit mode.
@@ -405,10 +418,10 @@ get_autocommit(Connection) ->
 
 %% @doc Like autocommit/1, but with an extra timeout attribute.
 -spec get_autocommit(connection(), timeout()) -> true | false.
-get_autocommit({connection, _Ref, Connection}, Timeout) ->
+get_autocommit(#connection{raw_connection=RawConnection}, Timeout) ->
     Ref = make_ref(),
-    ok = esqlite3_nif:get_autocommit(Connection, Ref, self()),
-    receive_answer(Connection, Ref, Timeout).
+    ok = esqlite3_nif:get_autocommit(RawConnection, Ref, self()),
+    receive_answer(RawConnection, Ref, Timeout).
 
 %% @doc Compile a SQL statement. Returns a cached compiled statement which can be used in
 %% queries.
@@ -419,12 +432,14 @@ prepare(Sql, Connection) ->
 
 %% @doc Like prepare/2, but with an extra timeout value.
 -spec prepare(sql(), connection(), timeout()) -> {ok, statement()} | {error, _}.
-prepare(Sql, {connection, _Ref, Connection}=C, Timeout) ->
+prepare(Sql, #connection{raw_connection=RawConnection}, Timeout) ->
     Ref = make_ref(),
-    ok = esqlite3_nif:prepare(Connection, Ref, self(), Sql),
-    case receive_answer(Connection, Ref, Timeout) of
-        {ok, Stmt} -> {ok, {statement, Stmt, C}};
-        Else -> Else
+    ok = esqlite3_nif:prepare(RawConnection, Ref, self(), Sql),
+    case receive_answer(RawConnection, Ref, Timeout) of
+        {ok, Stmt} ->
+            {ok, #statement{raw_statement=Stmt, raw_connection=RawConnection}};
+        Else ->
+            Else
     end.
 
 %% @doc Step
@@ -436,10 +451,10 @@ step(Stmt) ->
 %% @doc
 %%
 -spec step(statement(), timeout()) -> tuple() | '$busy' | '$done'.
-step({statement, Stmt, {connection, _, Conn}}, Timeout) ->
+step(#statement{raw_statement=RawStatement, raw_connection=RawConnection}, Timeout) ->
     Ref = make_ref(),
-    ok = esqlite3_nif:multi_step(Conn, Stmt, 1, Ref, self()),
-    case receive_answer(Conn, Ref, Timeout) of
+    ok = esqlite3_nif:multi_step(RawConnection, RawStatement, 1, Ref, self()),
+    case receive_answer(RawConnection, Ref, Timeout) of
         {rows, [Row | []]} -> {row, Row};
         {'$done', []} -> '$done';
         {'$busy', []} -> '$busy';
@@ -452,19 +467,19 @@ step({statement, Stmt, {connection, _, Conn}}, Timeout) ->
                 {rows, list(tuple())} |
                 {'$busy', list(tuple())} |
                 {'$done', list(tuple())} |
-                {error, term()}.
-multi_step({statement, Stmt, {connection, _, Conn}}, ChunkSize, Timeout) ->
+                {error, _}.
+multi_step(#statement{raw_statement=RawStatement, raw_connection=RawConnection}, ChunkSize, Timeout) ->
     Ref = make_ref(),
-    ok = esqlite3_nif:multi_step(Conn, Stmt, ChunkSize, Ref, self()),
-    receive_answer(Conn, Ref, Timeout).
+    ok = esqlite3_nif:multi_step(RawConnection, RawStatement, ChunkSize, Ref, self()),
+    receive_answer(RawConnection, Ref, Timeout).
 
 %% @doc Reset the prepared statement back to its initial state.
 %%
 -spec reset(statement()) -> ok | {error, _}.
-reset({statement, Stmt, {connection, _, Conn}}) ->
+reset(#statement{raw_statement=RawStatement, raw_connection=RawConnection}) ->
     Ref = make_ref(),
-    ok = esqlite3_nif:reset(Conn, Stmt, Ref, self()),
-    receive_answer(Conn, Ref, ?DEFAULT_TIMEOUT).
+    ok = esqlite3_nif:reset(RawConnection, RawStatement, Ref, self()),
+    receive_answer(RawConnection, Ref, ?DEFAULT_TIMEOUT).
 
 %% @doc Bind values to prepared statements
 %%
@@ -474,10 +489,10 @@ bind(Stmt, Args) ->
 
 %% @doc Bind values to prepared statements
 -spec bind(statement(), list(cell_type()), timeout()) -> ok | {error, _}.
-bind({statement, Stmt, {connection, _, Conn}}, Args, Timeout) ->
+bind(#statement{raw_statement=RawStatement, raw_connection=RawConnection}, Args, Timeout) ->
     Ref = make_ref(),
-    ok = esqlite3_nif:bind(Conn, Stmt, Ref, self(), Args),
-    receive_answer(Conn, Ref, Timeout).
+    ok = esqlite3_nif:bind(RawConnection, RawStatement, Ref, self(), Args),
+    receive_answer(RawConnection, Ref, Timeout).
 
 %% @doc Return the column names of the prepared statement.
 %%
@@ -486,22 +501,22 @@ column_names(Stmt) ->
     column_names(Stmt, ?DEFAULT_TIMEOUT).
 
 -spec column_names(statement(), timeout()) -> {atom()}.
-column_names({statement, Stmt, {connection, _, Conn}}, Timeout) ->
+column_names(#statement{raw_statement=RawStatement, raw_connection=RawConnection}, Timeout) ->
     Ref = make_ref(),
-    ok = esqlite3_nif:column_names(Conn, Stmt, Ref, self()),
-    receive_answer(Conn, Ref, Timeout).
+    ok = esqlite3_nif:column_names(RawConnection, RawStatement, Ref, self()),
+    receive_answer(RawConnection, Ref, Timeout).
 
 %% @doc Return the column types of the prepared statement.
 %%
 -spec column_types(statement()) -> {atom()}.
-column_types(Stmt) ->
-    column_types(Stmt, ?DEFAULT_TIMEOUT).
+column_types(Statement) ->
+    column_types(Statement, ?DEFAULT_TIMEOUT).
 
 -spec column_types(statement(), timeout()) -> {atom()}.
-column_types({statement, Stmt, {connection, _, Conn}}, Timeout) ->
+column_types(#statement{raw_statement=RawStatement, raw_connection=RawConnection}, Timeout) ->
     Ref = make_ref(),
-    ok = esqlite3_nif:column_types(Conn, Stmt, Ref, self()),
-    receive_answer(Conn, Ref, Timeout).
+    ok = esqlite3_nif:column_types(RawConnection, RawStatement, Ref, self()),
+    receive_answer(RawConnection, Ref, Timeout).
 
 %% @doc Close the database
 -spec close(connection()) -> ok | {error, _}.
@@ -510,10 +525,10 @@ close(Connection) ->
 
 %% @doc Close the database
 -spec close(connection(), timeout()) -> ok | {error, _}.
-close({connection, _Ref, Connection}, Timeout) ->
+close(#connection{raw_connection=RawConnection}, Timeout) ->
     Ref = make_ref(),
-    ok = esqlite3_nif:close(Connection, Ref, self()),
-    receive_answer(Connection, Ref, Timeout).
+    ok = esqlite3_nif:close(RawConnection, Ref, self()),
+    receive_answer(RawConnection, Ref, Timeout).
 
 
 %% @doc Flush any stale answers left in the mailbox of the current process.
@@ -527,12 +542,12 @@ flush() ->
 
 %% Internal functions
 
-receive_answer(Connection, Ref, Timeout) ->
+receive_answer(RawConnection, Ref, Timeout) ->
     receive
         {esqlite3, Ref, Resp} -> Resp
     after
         Timeout ->
-            ok = esqlite3_nif:interrupt(Connection),
+            ok = esqlite3_nif:interrupt(RawConnection),
             throw({error, timeout, Ref})
     end.
 

src/esqlite3_nif.erl

@@ -40,6 +40,11 @@
          close/3
         ]).
 
+-type raw_connection() :: reference().
+-type raw_statement() :: reference().
+
+-export_type([raw_connection/0, raw_statement/0]).
+
 -on_load(init/0).
 
 init() ->
@@ -52,7 +57,7 @@ init() ->
 
 %% @doc Start a low level thread which will can handle sqlite3 calls.
 %%
--spec start() -> {ok, esqlite:connection()} | {error, any()}.
+-spec start() -> {ok, raw_connection()} | {error, _}.
 start() ->
     erlang:nif_error(nif_library_not_loaded).
 
@@ -61,10 +66,11 @@ start() ->
 %% Sends an asynchronous open command over the connection and returns
 %% ok immediately. When the database is opened
 %%
--spec open(esqlite:connection(), reference(), pid(), string()) -> ok | {error, any()}.
+-spec open(raw_connection(), reference(), pid(), string()) -> ok | {error, _}.
 open(_Db, _Ref, _Dest, _Filename) ->
     erlang:nif_error(nif_library_not_loaded).
 
+-spec set_update_hook(raw_connection(), reference(), pid(), pid()) -> ok | {error, _}.
 set_update_hook(_Db, _Ref, _Dest, _Pid) ->
     erlang:nif_error(nif_library_not_loaded).
 
@@ -76,7 +82,7 @@ set_update_hook(_Db, _Ref, _Dest, _Pid) ->
 %% When the statement is executed Dest will receive message {Ref, answer()}
 %% with answer() integer | {error, reason()}
 %%
--spec exec(esqlite:connection(), reference(), pid(), string()) -> ok | {error, any()}.
+-spec exec(raw_connection(), reference(), pid(), string()) -> ok | {error, _}.
 exec(_Db, _Ref, _Dest, _Sql) ->
     erlang:nif_error(nif_library_not_loaded).
 
@@ -84,76 +90,78 @@ exec(_Db, _Ref, _Dest, _Sql) ->
 %%
 %% When the statement is executed Dest will receive message {Ref, answer()}
 %% with answer() integer | {error, reason()}
-%%
+-spec changes(raw_connection(), reference(), pid()) -> ok | {error, _}.
 changes(_Db, _Ref, _Dest) ->
     erlang:nif_error(nif_library_not_loaded).
 
 %% @doc
 %%
--spec prepare(esqlite:connection(), reference(), pid(), string()) -> ok | {error, any()}.
+-spec prepare(raw_connection(), reference(), pid(), string()) -> ok | {error, _}.
 prepare(_Db, _Ref, _Dest, _Sql) ->
     erlang:nif_error(nif_library_not_loaded).
 
 %% @doc
 %%
--spec multi_step(esqlite:connection(), esqlite:statement(), pos_integer(), reference(), pid()) -> ok | {error, any()}.
+-spec multi_step(raw_connection(), raw_statement(), pos_integer(), reference(), pid()) -> ok | {error, _}.
 multi_step(_Db, _Stmt, _Chunk_Size, _Ref, _Dest) ->
     erlang:nif_error(nif_library_not_loaded).
 
 %% @doc
 %%
--spec reset(esqlite:connection(), esqlite:statement(), reference(), pid()) -> ok | {error, any()}.
+-spec reset(raw_connection(), raw_statement(), reference(), pid()) -> ok | {error, _}.
 reset(_Db, _Stmt, _Ref, _Dest) ->
     erlang:nif_error(nif_library_not_loaded).
 
 %% @doc
 %%
--spec finalize(esqlite:connection(), esqlite:statement(), reference(), pid()) -> ok | {error, any()}.
+-spec finalize(raw_connection(), raw_statement(), reference(), pid()) -> ok | {error, _}.
 finalize(_Db, _Stmt, _Ref, _Dest) ->
     erlang:nif_error(nif_library_not_loaded).
 
 %% @doc Bind parameters to a prepared statement.
 %%
--spec bind(esqlite:connection(), esqlite:statement(), reference(), pid(), list(any())) -> ok | {error, any()}.
+-spec bind(raw_connection(), raw_statement(), reference(), pid(), list(any())) -> ok | {error, _}.
 bind(_Db, _Stmt, _Ref, _Dest, _Args) ->
     erlang:nif_error(nif_library_not_loaded).
 
 %% @doc Retrieve the column names of the prepared statement
 %%
--spec column_names(esqlite:connection(), esqlite:statement(), reference(), pid()) -> ok | {error, any()}.
+-spec column_names(raw_connection(), raw_statement(), reference(), pid()) -> ok | {error, _}.
 column_names(_Db, _Stmt, _Ref, _Dest) ->
     erlang:nif_error(nif_library_not_loaded).
 
 %% @doc Retrieve the column types of the prepared statement
 %%
--spec column_types(esqlite:connection(), esqlite:statement(), reference(), pid()) -> ok | {error, any()}.
+-spec column_types(raw_connection(), raw_statement(), reference(), pid()) -> ok | {error, _}.
 column_types(_Db, _Stmt, _Ref, _Dest) ->
     erlang:nif_error(nif_library_not_loaded).
 
 %% @doc Interrupt all active queries.
+-spec interrupt(raw_connection()) -> ok.
 interrupt(_Db) ->
     erlang:nif_error(nif_library_not_loaded).
 
 %% @doc Close the connection.
 %%
--spec close(esqlite:connection(), reference(), pid()) -> ok | {error, any()}.
+-spec close(raw_connection(), reference(), pid()) -> ok | {error, _}.
 close(_Db, _Ref, _Dest) ->
     erlang:nif_error(nif_library_not_loaded).
 
 %% @doc Insert record
 %%
--spec insert(esqlite:connection(), reference(), pid(), esqlite:sql()) -> ok | {error, any()}.
+-spec insert(raw_connection(), reference(), pid(), esqlite:sql()) -> ok | {error, _}.
 insert(_Db, _Ref, _Dest, _Sql) ->
     erlang:nif_error(nif_library_not_loaded).
 
 %% @doc Get the last insert rowid.
 %%
-%% @spec insert(connection(), Ref::reference(), Dest::pid()) -> {ok, integer()} | {error, message()}
+-spec last_insert_rowid(raw_connection(), reference(), pid()) -> ok | {error, _}.
 last_insert_rowid(_Db, _Ref, _Dest) ->
     erlang:nif_error(nif_library_not_loaded).
 
 %% @doc Get automcommit
 %%
--spec get_autocommit(esqlite:connection(), reference(), pid()) -> ok | {error, any()}.
+-spec get_autocommit(raw_connection(), reference(), pid()) -> ok | {error, _}.
 get_autocommit(_Db, _Ref, _Dest) ->
     erlang:nif_error(nif_library_not_loaded).
+

test/esqlite_test.erl

@@ -10,6 +10,21 @@ open_single_database_test() ->
     {ok, _C1} = esqlite3:open("test.db"),
     ok.
 
+close_test() ->
+    %% Open and close the database immediately
+    {ok, C} = esqlite3:open(":memory:"),
+    ok = esqlite3:close(C),
+
+    %% Check if functions still return sensible values.
+    {error, closed} = esqlite3:set_update_hook(self(), C),
+    {error, closed} = esqlite3:changes(C),
+    {error, closed} = esqlite3:get_autocommit(C),
+    {error, closed} = esqlite3:last_insert_rowid(C),
+
+    {error, _} = esqlite3:exec("create table test(one, two, three)", C),
+
+    ok.
+
 open_multiple_same_databases_test() ->
     {ok, _C1} = esqlite3:open("test.db"),
     {ok, _C2} = esqlite3:open("test.db"),