luadbi: comparison dbd/postgresql/statement.c

-:408291a6eb3e
+:c4f02fc67e5a
 #include "dbd_postgresql.h"
 #define MAX_PLACEHOLDERS	9999
 #define MAX_PLACEHOLDER_SIZE	(1+4) /* $\d{4} */
 static lua_push_type_t postgresql_to_lua_push(unsigned int postgresql_type) {
 lua_push_type_t lua_type;
 }
 return lua_type;
 }
+/*
+* replace '?' placeholders with $\d+ placeholders
+* to be compatible with PSQL API
+*/
 static char *replace_placeholders(lua_State *L, const char *sql) {
 size_t len = strlen(sql);
 int num_placeholders = 0;
 int extra_space = 0;
 int i;
 char *newsql;
 int newpos = 1;
 int ph_num = 1;
 int in_quote = 0;
+/*
+* dumb count of all '?'
+* this will match more placeholders than necessesary
+* but it's safer to allocate more placeholders at the
+* cost of a few bytes than risk a buffer overflow
+*/
 for (i = 1; i < len; i++) {
 	if (sql[i] == '?') {
 	    num_placeholders++;
 	}
 }
+/*
+* this is MAX_PLACEHOLDER_SIZE-1 because the '?' is
+* replaced with '$'
+*/
 extra_space = num_placeholders * (MAX_PLACEHOLDER_SIZE-1);
+/*
+* allocate a new string for the converted SQL statement
+*/
 newsql = malloc(sizeof(char) * (len+extra_space+1));
 memset(newsql, 0, sizeof(char) * (len+extra_space+1));
-/* copy first char */
+/*
+* copy first char. In valid SQL this cannot be a placeholder
+*/
 newsql[0] = sql[0];
+/*
+* only replace '?' not in a single quoted string
+*/
 for (i = 1; i < len; i++) {
+	/*
+	 * don't change the quote flag if the ''' is preceded
+	 * bt a '\' to account for escaping
+	 */
 	if (sql[i] == '\'' && sql[i-1] != '\\') {
 	    in_quote = !in_quote;
 	}
 	if (sql[i] == '?' && !in_quote) {
 	    newsql[newpos] = sql[i];
 	    newpos++;
 	}
 }
-/* terminate string on the last position */
+/*
+* terminate string on the last position
+*/
 newsql[newpos] = '\0';
 /* fprintf(stderr, "[%s]\n", newsql); */
 return newsql;
 }
+/*
+* success = statement:close()
+*/
 static int statement_close(lua_State *L) {
 statement_t *statement = (statement_t *)luaL_checkudata(L, 1, DBD_POSTGRESQL_STATEMENT);
 if (statement->result) {
 	PQclear(statement->result);
 }
 return 0;
 }
+/*
+* success = statement:execute(...)
+*/
 static int statement_execute(lua_State *L) {
 int n = lua_gettop(L);
 statement_t *statement = (statement_t *)luaL_checkudata(L, 1, DBD_POSTGRESQL_STATEMENT);
 int num_bind_params = n - 1;
 ExecStatusType status;
 statement->tuple = 0;
 params = malloc(num_bind_params * sizeof(params));
+/*
+* convert and copy parameters into a string array
+*/
 for (p = 2; p <= n; p++) {
 	int i = p - 2;
 	if (lua_isnil(L, p)) {
 	    params[i] = NULL;
 	NULL,
 NULL,
 0
 );
+/*
+* free string array
+*/
 for (p = 0; p < num_bind_params; p++) {
 	if (params[p]) {
 	    free(params[p]);
 	}
 }
 lua_pushboolean(L, 1);
 return 1;
 }
+/*
+* must be called after an execute
+*/
 static int statement_fetch_impl(lua_State *L, int named_columns) {
 statement_t *statement = (statement_t *)luaL_checkudata(L, 1, DBD_POSTGRESQL_STATEMENT);
 int tuple = statement->tuple++;
 int i;
 int num_columns;
 }
 	} else {
 	    const char *value = PQgetvalue(statement->result, tuple, i);
 	    lua_push_type_t lua_push = postgresql_to_lua_push(PQftype(statement->result, i));
+	    /*
+* data is returned as strings from PSQL
+*/
 if (lua_push == LUA_PUSH_NIL) {
 if (named_columns) {
 LUA_PUSH_ATTRIB_NIL(name);
 } else {
 LUA_PUSH_ARRAY_NIL(d);
 LUA_PUSH_ATTRIB_STRING(name, value);
 } else {
 LUA_PUSH_ARRAY_STRING(d, value);
 }
 } else if (lua_push == LUA_PUSH_BOOLEAN) {
+		/*
+* booleans are returned as a string
+* either 't' or 'f'
+*/
 int val = value[0] == 't' ? 1 : 0;
 if (named_columns) {
 LUA_PUSH_ATTRIB_BOOL(name, val);
 } else {
 }
 return 1;
 }
+/*
+* array = statement:fetch()
+*/
 static int statement_fetch(lua_State *L) {
 return statement_fetch_impl(L, 0);
 }
+/*
+* hashmap = statement:fetchtable()
+*/
 static int statement_fetchtable(lua_State *L) {
 return statement_fetch_impl(L, 1);
 }
+/*
+* __gc
+*/
 static int statement_gc(lua_State *L) {
 /* always free the handle */
 statement_close(L);
 return 0;
 }
-static const luaL_Reg statement_methods[] = {
-{"close", statement_close},
-{"execute", statement_execute},
-{"fetch", statement_fetch},
-{"fetchtable", statement_fetchtable},
-{NULL, NULL}
-};
-static const luaL_Reg statement_class_methods[] = {
-{NULL, NULL}
-};
 int dbd_postgresql_statement_create(lua_State *L, connection_t *conn, const char *sql_query) {
 statement_t *statement = NULL;
 ExecStatusType status;
 PGresult *result = NULL;
 char *new_sql;
 char name[IDLEN];
+/*
+* convert SQL string into a PSQL API compatible SQL statement
+*/
 new_sql = replace_placeholders(L, sql_query);
 snprintf(name, IDLEN, "%017u", ++conn->statement_id);
 result = PQprepare(conn->postgresql, name, new_sql, 0, NULL);
+/*
+* free converted statement after use
+*/
 free(new_sql);
 if (!result) {
 	luaL_error(L, "Unable to allocate prepare result handle");
 }
 return 1;
 }
 int dbd_postgresql_statement(lua_State *L) {
+static const luaL_Reg statement_methods[] = {
+	{"close", statement_close},
+	{"execute", statement_execute},
+	{"fetch", statement_fetch},
+	{"fetchtable", statement_fetchtable},
+	{NULL, NULL}
+};
+static const luaL_Reg statement_class_methods[] = {
+	{NULL, NULL}
+};
 luaL_newmetatable(L, DBD_POSTGRESQL_STATEMENT);
 luaL_register(L, 0, statement_methods);
 lua_pushvalue(L,-1);
 lua_setfield(L, -2, "__index");

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comparison: dbd/postgresql/statement.c

dbd/postgresql/statement.c