Add C based module + lua based API code (WIP)

modules/sqlitedb.c

@@ -0,0 +1,125 @@
+#include <sqlite3.h>
+#include "lua/lualib.h"
+
+typedef sqlite3 *sqldb;
+
+static int l_getdb(lua_State *L)
+{
+    const char *file = luaL_checkstring(L, 1);
+    sqlite3 *db;
+    int rc = sqlite3_open(file, &db);
+    if (rc != SQLITE_OK)
+    {
+        lua_pushnil(L);
+        lua_pushstring(L,sqlite3_errmsg(db));
+        sqlite3_close(db);
+        return 2;
+    }
+    lua_pushlightuserdata(L, db);
+    return 1;
+}
+
+static int l_db_close(lua_State *L)
+{
+    sqldb db = (sqldb)lua_touserdata(L, 1);
+    if (db)
+    {
+            sqlite3_close(db);
+    }
+    db = NULL;
+    return 0;
+}
+static int l_db_exec(lua_State *L)
+{
+    sqldb db = (sqldb)lua_touserdata(L, 1);
+    const char *sql = luaL_checkstring(L, 2);
+    int r = 0;
+    if(!db)
+    {
+        lua_pushboolean(L, 0);
+        lua_pushstring(L,"Invalid database handle");
+        return 2;
+    }
+    
+    char *err_msg = 0;
+    sqlite3_mutex_enter(sqlite3_db_mutex(db));
+    int rc = sqlite3_exec(db, sql, NULL, 0, &err_msg);
+    sqlite3_mutex_leave(sqlite3_db_mutex(db));
+    if (rc != SQLITE_OK)
+    {
+        lua_pushboolean(L, 0);
+        lua_pushstring(L,err_msg);
+        sqlite3_free(err_msg);
+        return 2;
+    }
+
+    lua_pushboolean(L, 1);
+    return 1;
+}
+static int l_db_lastid(lua_State *L)
+{
+    sqldb db = (sqldb)lua_touserdata(L, 1);
+
+    int idx = -1;
+    if (db)
+        idx = sqlite3_last_insert_rowid(db);
+    lua_pushnumber(L, idx);
+    return 1;
+}
+static int l_db_query(lua_State *L)
+{
+    sqldb db = (sqldb)lua_touserdata(L, 1);
+    const char *query = luaL_checkstring(L, 2);
+    if (!db)
+    {
+        lua_pushnil(L);
+        return 1;
+    }
+
+    sqlite3_stmt *statement;
+
+    if (sqlite3_prepare_v2(db, query, -1, &statement, 0) == SQLITE_OK)
+    {
+        int cols = sqlite3_column_count(statement);
+        int result = 0;
+        int cnt = 1;
+        // new table for data
+        lua_newtable(L);
+        while ((result = sqlite3_step(statement)) == SQLITE_ROW)
+        {
+            lua_pushnumber(L, cnt);
+            lua_newtable(L);
+            for (int col = 0; col < cols; col++)
+            {
+                const char *value = (const char *)sqlite3_column_text(statement, col);
+                const char *name = sqlite3_column_name(statement, col);
+                lua_pushstring(L, name);
+                lua_pushstring(L, value);
+                lua_settable(L, -3);
+            }
+            lua_settable(L, -3);
+            cnt++;
+        }
+        sqlite3_finalize(statement);
+    }
+    else
+    {
+        lua_pushnil(L);
+        lua_pushstring(L, sqlite3_errmsg(db));
+        return 2;
+    }
+    return 1;
+}
+static const struct luaL_Reg sqlite[] = {
+    {"db", l_getdb},
+    {"dbclose", l_db_close},
+    {"query", l_db_query},
+    {"last_insert_id", l_db_lastid},
+    {"exec", l_db_exec},
+    {NULL, NULL}};
+
+int luaopen_sqlitedb(lua_State *L)
+{
+    luaL_newlib(L, sqlite);
+    return 1;
+}