Add database and statement readonly checks to sqlite in redbean (#914)

test/tool/net/sqlite_test.lua

@@ -0,0 +1,31 @@
+-- Copyright 2023 Justine Alexandra Roberts Tunney
+--
+-- Permission to use, copy, modify, and/or distribute this software for
+-- any purpose with or without fee is hereby granted, provided that the
+-- above copyright notice and this permission notice appear in all copies.
+--
+-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+-- WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+-- WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
+-- AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
+-- DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
+-- PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+-- TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+-- PERFORMANCE OF THIS SOFTWARE.
+
+local sqlite3 = require "lsqlite3"
+local db = assert(sqlite3.open("file:/memdb1?vfs=memdb&mode=ro",
+  sqlite3.OPEN_URI + sqlite3.OPEN_READWRITE + sqlite3.OPEN_CREATE))
+assert(db:readonly() == true)
+db = sqlite3.open("file:/memdb1?vfs=memdb",
+  sqlite3.OPEN_URI + sqlite3.OPEN_READWRITE + sqlite3.OPEN_CREATE)
+assert(db:readonly() == false)
+assert(db:readonly("main") == false)
+assert(db:readonly("foo") == nil)
+
+assert(db:exec("create table foo(a)") == 0)
+
+local st = assert(db:prepare("select * from foo"))
+assert(st:readonly() == true)
+st = assert(db:prepare("insert into foo (a) values (1)"))
+assert(st:readonly() == false)

tool/net/lsqlite3.c

@@ -234,6 +234,12 @@ static int dbvm_isopen(lua_State *L) {
     return 1;
 }
 
+static int dbvm_readonly(lua_State *L) {
+    sdb_vm *svm = lsqlite_checkvm(L, 1);
+    lua_pushboolean(L, sqlite3_stmt_readonly(svm->vm));
+    return 1;
+}
+
 static int dbvm_tostring(lua_State *L) {
     char buff[40];
     sdb_vm *svm = lsqlite_getvm(L, 1);
@@ -908,6 +914,21 @@ static int pusherr(lua_State *L, int rc) {
     return 2;
 }
 
+static int pusherrstr(lua_State *L, char *str) {
+    lua_pushnil(L);
+    lua_pushstring(L, str);
+    return 2;
+}
+
+static int db_readonly(lua_State *L) {
+    sdb *db = lsqlite_checkdb(L, 1);
+    const char *zDb = luaL_optstring(L, 2, "main");
+    int res = sqlite3_db_readonly(db->db, zDb);
+    if (res == -1) return pusherrstr(L, "unknown (not attached) database name");
+    lua_pushboolean(L, res);
+    return 1;
+}
+
 static int db_wal_checkpoint(lua_State *L) {
     sdb *db = lsqlite_checkdb(L, 1);
     int eMode = luaL_optinteger(L, 2, SQLITE_CHECKPOINT_PASSIVE);
@@ -1748,16 +1769,15 @@ static int db_gc(lua_State *L) {
     return 0;
 }
 
+#ifdef SQLITE_ENABLE_DESERIALIZE
+
 static int db_serialize(lua_State *L) {
-    sdb *db = lsqlite_getdb(L, 1);
+    sdb *db = lsqlite_checkdb(L, 1);
     sqlite_int64 size = 0;
 
-    if (db->db == NULL) /* ignore closed databases */
-        return 0;
-    
     char *buffer = (char *)sqlite3_serialize(db->db, "main", &size, 0);
-    if (buffer == NULL) /* ignore failed database serialization */
-        return 0;
+    if (buffer == NULL)
+        return pusherrstr(L, "failed to serialize");
 
     lua_pushlstring(L, buffer, size);
     free(buffer);
@@ -1765,15 +1785,12 @@ static int db_serialize(lua_State *L) {
 }
 
 static int db_deserialize(lua_State *L) {
-    sdb *db = lsqlite_getdb(L, 1);
+    sdb *db = lsqlite_checkdb(L, 1);
     size_t size = 0;
 
-    if (db->db == NULL) /* ignore closed databases */
-        return 0;
-
     const char *buffer = luaL_checklstring(L, 2, &size);
-    if (buffer == NULL || size == 0) /* ignore empty database content */
-        return 0;
+    if (buffer == NULL || size == 0)
+        return pusherrstr(L, "failed to deserialize");
 
     const char *sqlbuf = memcpy(sqlite3_malloc(size), buffer, size);
     sqlite3_deserialize(db->db, "main", (void *)sqlbuf, size, size,
@@ -1781,6 +1798,8 @@ static int db_deserialize(lua_State *L) {
     return 0;
 }
 
+#endif
+
 #ifdef SQLITE_ENABLE_SESSION
 
 /*
@@ -2602,6 +2621,7 @@ static const struct {
 
 static const luaL_Reg dblib[] = {
     {"isopen",              db_isopen               },
+    {"readonly",            db_readonly             },
     {"last_insert_rowid",   db_last_insert_rowid    },
     {"changes",             db_changes              },
     {"total_changes",       db_total_changes        },
@@ -2634,9 +2654,6 @@ static const luaL_Reg dblib[] = {
     {"close",               db_close                },
     {"close_vm",            db_close_vm             },
 
-    {"serialize",           db_serialize            },
-    {"deserialize",         db_deserialize          },
-
 #ifdef SQLITE_ENABLE_SESSION
     {"create_session",      db_create_session       },
     {"create_rebaser",      db_create_rebaser       },
@@ -2646,6 +2663,11 @@ static const luaL_Reg dblib[] = {
     {"iterate_changeset",   db_iterate_changeset    },
 #endif
 
+#ifdef SQLITE_ENABLE_DESERIALIZE
+    {"serialize",           db_serialize            },
+    {"deserialize",         db_deserialize          },
+#endif
+
     {"__tostring",          db_tostring             },
     {"__gc",                db_gc                   },
 
@@ -2654,6 +2676,7 @@ static const luaL_Reg dblib[] = {
 
 static const luaL_Reg vmlib[] = {
     {"isopen",              dbvm_isopen             },
+    {"readonly",            dbvm_readonly           },
 
     {"step",                dbvm_step               },
     {"reset",               dbvm_reset              },