mirror of
https://github.com/pocketpy/pocketpy
synced 2025-11-09 21:20:17 +00:00
Rollback vm.hpp
This commit is contained in:
parent
1adbc0d036
commit
8ba1a9d245
@ -98,6 +98,6 @@ QualifierAlignment: Custom
|
||||
QualifierOrder: ["constexpr", "const", "inline", "static", "type"]
|
||||
SortIncludes: Never
|
||||
SortUsingDeclarations: LexicographicNumeric
|
||||
IncludeBlocksStyle: Merge
|
||||
IncludeBlocks: Merge
|
||||
|
||||
WhitespaceSensitiveMacros: ["PK_PROTECTED"]
|
||||
|
||||
@ -1,13 +1,13 @@
|
||||
#pragma once
|
||||
|
||||
#include "pocketpy/objects/object.hpp"
|
||||
#include "pocketpy/interpreter/frame.hpp"
|
||||
#include "pocketpy/interpreter/gc.hpp"
|
||||
#include "pocketpy/interpreter/profiler.hpp"
|
||||
#include "pocketpy/objects/builtins.hpp"
|
||||
#include "pocketpy/objects/dict.hpp"
|
||||
#include "pocketpy/objects/error.hpp"
|
||||
#include "pocketpy/objects/object.hpp"
|
||||
#include "pocketpy/objects/stackmemory.hpp"
|
||||
#include "pocketpy/objects/builtins.hpp"
|
||||
#include "pocketpy/interpreter/gc.hpp"
|
||||
#include "pocketpy/interpreter/frame.hpp"
|
||||
#include "pocketpy/interpreter/profiler.hpp"
|
||||
|
||||
#include <stdexcept>
|
||||
|
||||
@ -226,42 +226,39 @@ public:
|
||||
const bool enable_os;
|
||||
VM(bool enable_os = true);
|
||||
|
||||
// clang-format off
|
||||
// clang-format off
|
||||
#if PK_REGION("Python Equivalents")
|
||||
Str py_str(PyVar obj); // x -> str(x)
|
||||
Str py_repr(PyVar obj); // x -> repr(x)
|
||||
Str py_json(PyVar obj); // x -> json.dumps(x)
|
||||
Str py_str(PyVar obj); // x -> str(x)
|
||||
Str py_repr(PyVar obj); // x -> repr(x)
|
||||
Str py_json(PyVar obj); // x -> json.dumps(x)
|
||||
|
||||
PyVar py_iter(PyVar obj); // x -> iter(x)
|
||||
PyVar py_next(PyVar); // x -> next(x)
|
||||
PyVar _py_next(const PyTypeInfo*, PyVar); // x -> next(x) with type info cache
|
||||
PyObject* py_import(Str path, bool throw_err = true); // x -> __import__(x)
|
||||
PyVar py_negate(PyVar obj); // x -> -x
|
||||
PyVar py_iter(PyVar obj); // x -> iter(x)
|
||||
PyVar py_next(PyVar); // x -> next(x)
|
||||
PyVar _py_next(const PyTypeInfo*, PyVar); // x -> next(x) with type info cache
|
||||
PyObject* py_import(Str path, bool throw_err=true); // x -> __import__(x)
|
||||
PyVar py_negate(PyVar obj); // x -> -x
|
||||
|
||||
List py_list(PyVar); // x -> list(x)
|
||||
bool py_callable(PyVar obj); // x -> callable(x)
|
||||
|
||||
bool py_bool(PyVar obj) { // x -> bool(x)
|
||||
if(obj.type == tp_bool) { return obj._0; }
|
||||
List py_list(PyVar); // x -> list(x)
|
||||
bool py_callable(PyVar obj); // x -> callable(x)
|
||||
bool py_bool(PyVar obj){ // x -> bool(x)
|
||||
if(obj.type == tp_bool) return obj._0;
|
||||
return __py_bool_non_trivial(obj);
|
||||
}
|
||||
i64 py_hash(PyVar obj); // x -> hash(x)
|
||||
|
||||
i64 py_hash(PyVar obj); // x -> hash(x)
|
||||
|
||||
bool py_eq(PyVar lhs, PyVar rhs); // (lhs, rhs) -> lhs == rhs
|
||||
bool py_lt(PyVar lhs, PyVar rhs); // (lhs, rhs) -> lhs < rhs
|
||||
bool py_le(PyVar lhs, PyVar rhs); // (lhs, rhs) -> lhs <= rhs
|
||||
bool py_gt(PyVar lhs, PyVar rhs); // (lhs, rhs) -> lhs > rhs
|
||||
bool py_ge(PyVar lhs, PyVar rhs); // (lhs, rhs) -> lhs >= rhs
|
||||
|
||||
bool py_ne(PyVar lhs, PyVar rhs) { // (lhs, rhs) -> lhs != rhs
|
||||
bool py_eq(PyVar lhs, PyVar rhs); // (lhs, rhs) -> lhs == rhs
|
||||
bool py_lt(PyVar lhs, PyVar rhs); // (lhs, rhs) -> lhs < rhs
|
||||
bool py_le(PyVar lhs, PyVar rhs); // (lhs, rhs) -> lhs <= rhs
|
||||
bool py_gt(PyVar lhs, PyVar rhs); // (lhs, rhs) -> lhs > rhs
|
||||
bool py_ge(PyVar lhs, PyVar rhs); // (lhs, rhs) -> lhs >= rhs
|
||||
bool py_ne(PyVar lhs, PyVar rhs){ // (lhs, rhs) -> lhs != rhs
|
||||
return !py_eq(lhs, rhs);
|
||||
}
|
||||
|
||||
PyVar py_op(std::string_view name); // (name) -> operator.name
|
||||
PyVar py_op(std::string_view name); // (name) -> operator.name
|
||||
|
||||
void py_exec(std::string_view, PyVar, PyVar); // exec(source, globals, locals)
|
||||
PyVar py_eval(std::string_view, PyVar, PyVar); // eval(source, globals, locals)
|
||||
void py_exec(std::string_view, PyVar, PyVar); // exec(source, globals, locals)
|
||||
PyVar py_eval(std::string_view, PyVar, PyVar); // eval(source, globals, locals)
|
||||
#endif
|
||||
|
||||
#if PK_REGION("Utility Methods")
|
||||
@ -270,69 +267,59 @@ public:
|
||||
i64 normalized_index(i64 index, int size);
|
||||
Str disassemble(CodeObject_ co);
|
||||
void parse_int_slice(const Slice& s, int length, int& start, int& stop, int& step);
|
||||
|
||||
void obj_gc_mark(PyVar obj) {
|
||||
if(obj.is_ptr) { __obj_gc_mark(obj.get()); }
|
||||
}
|
||||
|
||||
void obj_gc_mark(PyObject* p) {
|
||||
if(p) { __obj_gc_mark(p); }
|
||||
}
|
||||
void obj_gc_mark(PyVar obj) { if(obj.is_ptr) __obj_gc_mark(obj.get()); }
|
||||
void obj_gc_mark(PyObject* p) { if(p) __obj_gc_mark(p); }
|
||||
#endif
|
||||
|
||||
#if PK_REGION("Name Lookup Methods")
|
||||
PyVar* find_name_in_mro(Type cls, StrName name);
|
||||
PyVar get_unbound_method(PyVar obj, StrName name, PyVar* self, bool throw_err = true, bool fallback = false);
|
||||
PyVar getattr(PyVar obj, StrName name, bool throw_err = true);
|
||||
PyVar get_unbound_method(PyVar obj, StrName name, PyVar* self, bool throw_err=true, bool fallback=false);
|
||||
PyVar getattr(PyVar obj, StrName name, bool throw_err=true);
|
||||
void delattr(PyVar obj, StrName name);
|
||||
void setattr(PyVar obj, StrName name, PyVar value);
|
||||
#endif
|
||||
|
||||
#if PK_REGION("Source Execution Methods")
|
||||
CodeObject_
|
||||
compile(std::string_view source, const Str& filename, CompileMode mode, bool unknown_global_scope = false);
|
||||
CodeObject_ compile(std::string_view source, const Str& filename, CompileMode mode, bool unknown_global_scope=false);
|
||||
Str precompile(std::string_view source, const Str& filename, CompileMode mode);
|
||||
PyVar exec(std::string_view source, Str filename, CompileMode mode, PyObject* _module = nullptr);
|
||||
PyVar exec(std::string_view source, Str filename, CompileMode mode, PyObject* _module=nullptr);
|
||||
PyVar exec(std::string_view source);
|
||||
PyVar eval(std::string_view source);
|
||||
|
||||
template <typename... Args>
|
||||
PyVar _exec(Args&&... args) {
|
||||
template<typename ...Args>
|
||||
PyVar _exec(Args&&... args){
|
||||
callstack.emplace(s_data._sp, std::forward<Args>(args)...);
|
||||
return __run_top_frame();
|
||||
}
|
||||
#endif
|
||||
|
||||
#if PK_REGION("Invocation Methods")
|
||||
PyVar vectorcall(int ARGC, int KWARGC = 0, bool op_call = false);
|
||||
PyVar vectorcall(int ARGC, int KWARGC=0, bool op_call=false);
|
||||
|
||||
template <typename... Args>
|
||||
PyVar call(PyVar callable, Args&&... args) {
|
||||
PUSH(callable);
|
||||
PUSH(PY_NULL);
|
||||
template<typename... Args>
|
||||
PyVar call(PyVar callable, Args&&... args){
|
||||
PUSH(callable); PUSH(PY_NULL);
|
||||
__push_varargs(args...);
|
||||
return vectorcall(sizeof...(args));
|
||||
}
|
||||
|
||||
template <typename... Args>
|
||||
PyVar call_method(PyVar self, PyVar callable, Args&&... args) {
|
||||
PUSH(callable);
|
||||
PUSH(self);
|
||||
template<typename... Args>
|
||||
PyVar call_method(PyVar self, PyVar callable, Args&&... args){
|
||||
PUSH(callable); PUSH(self);
|
||||
__push_varargs(args...);
|
||||
return vectorcall(sizeof...(args));
|
||||
}
|
||||
|
||||
template <typename... Args>
|
||||
PyVar call_method(PyVar self, StrName name, Args&&... args) {
|
||||
template<typename... Args>
|
||||
PyVar call_method(PyVar self, StrName name, Args&&... args){
|
||||
PyVar callable = get_unbound_method(self, name, &self);
|
||||
return call_method(self, callable, args...);
|
||||
}
|
||||
#endif
|
||||
|
||||
#if PK_REGION("Logging Methods")
|
||||
virtual void stdout_write(const Str& s) { _stdout(s.data, s.size); }
|
||||
|
||||
virtual void stderr_write(const Str& s) { _stderr(s.data, s.size); }
|
||||
virtual void stdout_write(const Str& s){ _stdout(s.data, s.size); }
|
||||
virtual void stderr_write(const Str& s){ _stderr(s.data, s.size); }
|
||||
#endif
|
||||
|
||||
#if PK_REGION("Magic Bindings")
|
||||
@ -375,162 +362,106 @@ public:
|
||||
#endif
|
||||
|
||||
#if PK_REGION("General Bindings")
|
||||
PyObject* bind_func(PyObject* obj,
|
||||
StrName name,
|
||||
int argc,
|
||||
NativeFuncC fn,
|
||||
any userdata = {},
|
||||
BindType bt = BindType::DEFAULT);
|
||||
|
||||
PyObject* bind_func(Type type,
|
||||
StrName name,
|
||||
int argc,
|
||||
NativeFuncC fn,
|
||||
any userdata = {},
|
||||
BindType bt = BindType::DEFAULT) {
|
||||
PyObject* bind_func(PyObject* obj, StrName name, int argc, NativeFuncC fn, any userdata={}, BindType bt=BindType::DEFAULT);
|
||||
PyObject* bind_func(Type type, StrName name, int argc, NativeFuncC fn, any userdata={}, BindType bt=BindType::DEFAULT){
|
||||
return bind_func(_t(type), name, argc, fn, std::move(userdata), bt);
|
||||
}
|
||||
|
||||
PyObject* bind_property(PyObject*, const char*, NativeFuncC fget, NativeFuncC fset = nullptr);
|
||||
template <typename T, typename F, bool ReadOnly = false>
|
||||
PyObject* bind_property(PyObject*, const char*, NativeFuncC fget, NativeFuncC fset=nullptr);
|
||||
template<typename T, typename F, bool ReadOnly=false>
|
||||
PyObject* bind_field(PyObject*, const char*, F T::*);
|
||||
|
||||
PyObject* bind(PyObject*, const char*, NativeFuncC, any userdata = {}, BindType bt = BindType::DEFAULT);
|
||||
template <typename Ret, typename... Params>
|
||||
PyObject* bind(PyObject*, const char*, Ret (*)(Params...), BindType bt = BindType::DEFAULT);
|
||||
template <typename Ret, typename T, typename... Params>
|
||||
PyObject* bind(PyObject*, const char*, Ret (T::*)(Params...), BindType bt = BindType::DEFAULT);
|
||||
PyObject* bind(PyObject*, const char*, NativeFuncC, any userdata={}, BindType bt=BindType::DEFAULT);
|
||||
template<typename Ret, typename... Params>
|
||||
PyObject* bind(PyObject*, const char*, Ret(*)(Params...), BindType bt=BindType::DEFAULT);
|
||||
template<typename Ret, typename T, typename... Params>
|
||||
PyObject* bind(PyObject*, const char*, Ret(T::*)(Params...), BindType bt=BindType::DEFAULT);
|
||||
|
||||
PyObject*
|
||||
bind(PyObject*, const char*, const char*, NativeFuncC, any userdata = {}, BindType bt = BindType::DEFAULT);
|
||||
template <typename Ret, typename... Params>
|
||||
PyObject* bind(PyObject*, const char*, const char*, Ret (*)(Params...), BindType bt = BindType::DEFAULT);
|
||||
template <typename Ret, typename T, typename... Params>
|
||||
PyObject* bind(PyObject*, const char*, const char*, Ret (T::*)(Params...), BindType bt = BindType::DEFAULT);
|
||||
PyObject* bind(PyObject*, const char*, const char*, NativeFuncC, any userdata={}, BindType bt=BindType::DEFAULT);
|
||||
template<typename Ret, typename... Params>
|
||||
PyObject* bind(PyObject*, const char*, const char*, Ret(*)(Params...), BindType bt=BindType::DEFAULT);
|
||||
template<typename Ret, typename T, typename... Params>
|
||||
PyObject* bind(PyObject*, const char*, const char*, Ret(T::*)(Params...), BindType bt=BindType::DEFAULT);
|
||||
#endif
|
||||
|
||||
#if PK_REGION("Error Reporting Methods")
|
||||
[[noreturn]] void _error(PyVar);
|
||||
|
||||
[[noreturn]] void StackOverflowError() { __builtin_error("StackOverflowError"); }
|
||||
|
||||
[[noreturn]] void IOError(const Str& msg) { __builtin_error("IOError", msg); }
|
||||
|
||||
[[noreturn]] void NotImplementedError() { __builtin_error("NotImplementedError"); }
|
||||
|
||||
[[noreturn]] void TypeError(const Str& msg) { __builtin_error("TypeError", msg); }
|
||||
|
||||
[[noreturn]] void TypeError(Type expected, Type actual) {
|
||||
TypeError("expected " + _type_name(vm, expected).escape() + ", got " + _type_name(vm, actual).escape());
|
||||
}
|
||||
|
||||
[[noreturn]] void IndexError(const Str& msg) { __builtin_error("IndexError", msg); }
|
||||
|
||||
[[noreturn]] void ValueError(const Str& msg) { __builtin_error("ValueError", msg); }
|
||||
|
||||
[[noreturn]] void RuntimeError(const Str& msg) { __builtin_error("RuntimeError", msg); }
|
||||
|
||||
[[noreturn]] void ZeroDivisionError(const Str& msg) { __builtin_error("ZeroDivisionError", msg); }
|
||||
|
||||
[[noreturn]] void ZeroDivisionError() { __builtin_error("ZeroDivisionError", "division by zero"); }
|
||||
|
||||
[[noreturn]] void NameError(StrName name) {
|
||||
__builtin_error("NameError", _S("name ", name.escape() + " is not defined"));
|
||||
}
|
||||
|
||||
[[noreturn]] void UnboundLocalError(StrName name) {
|
||||
__builtin_error("UnboundLocalError", _S("local variable ", name.escape() + " referenced before assignment"));
|
||||
}
|
||||
|
||||
[[noreturn]] void KeyError(PyVar obj) { __builtin_error("KeyError", obj); }
|
||||
|
||||
[[noreturn]] void ImportError(const Str& msg) { __builtin_error("ImportError", msg); }
|
||||
|
||||
[[noreturn]] void AssertionError(const Str& msg) { __builtin_error("AssertionError", msg); }
|
||||
|
||||
[[noreturn]] void AssertionError() { __builtin_error("AssertionError"); }
|
||||
|
||||
[[noreturn]] void NotImplementedError(){ __builtin_error("NotImplementedError"); }
|
||||
[[noreturn]] void TypeError(const Str& msg){ __builtin_error("TypeError", msg); }
|
||||
[[noreturn]] void TypeError(Type expected, Type actual) { TypeError("expected " + _type_name(vm, expected).escape() + ", got " + _type_name(vm, actual).escape()); }
|
||||
[[noreturn]] void IndexError(const Str& msg){ __builtin_error("IndexError", msg); }
|
||||
[[noreturn]] void ValueError(const Str& msg){ __builtin_error("ValueError", msg); }
|
||||
[[noreturn]] void RuntimeError(const Str& msg){ __builtin_error("RuntimeError", msg); }
|
||||
[[noreturn]] void ZeroDivisionError(const Str& msg){ __builtin_error("ZeroDivisionError", msg); }
|
||||
[[noreturn]] void ZeroDivisionError(){ __builtin_error("ZeroDivisionError", "division by zero"); }
|
||||
[[noreturn]] void NameError(StrName name){ __builtin_error("NameError", _S("name ", name.escape() + " is not defined")); }
|
||||
[[noreturn]] void UnboundLocalError(StrName name){ __builtin_error("UnboundLocalError", _S("local variable ", name.escape() + " referenced before assignment")); }
|
||||
[[noreturn]] void KeyError(PyVar obj){ __builtin_error("KeyError", obj); }
|
||||
[[noreturn]] void ImportError(const Str& msg){ __builtin_error("ImportError", msg); }
|
||||
[[noreturn]] void AssertionError(const Str& msg){ __builtin_error("AssertionError", msg); }
|
||||
[[noreturn]] void AssertionError(){ __builtin_error("AssertionError"); }
|
||||
[[noreturn]] void BinaryOptError(const char* op, PyVar _0, PyVar _1);
|
||||
[[noreturn]] void AttributeError(PyVar obj, StrName name);
|
||||
|
||||
[[noreturn]] void AttributeError(const Str& msg) { __builtin_error("AttributeError", msg); }
|
||||
[[noreturn]] void AttributeError(const Str& msg){ __builtin_error("AttributeError", msg); }
|
||||
#endif
|
||||
|
||||
#if PK_REGION("Type Checking Methods")
|
||||
bool isinstance(PyVar obj, Type base);
|
||||
bool issubclass(Type cls, Type base);
|
||||
void check_type(PyVar obj, Type type){ if(!is_type(obj, type)) TypeError(type, _tp(obj)); }
|
||||
void check_compatible_type(PyVar obj, Type type){ if(!isinstance(obj, type)) TypeError(type, _tp(obj)); }
|
||||
|
||||
void check_type(PyVar obj, Type type) {
|
||||
if(!is_type(obj, type)) { TypeError(type, _tp(obj)); }
|
||||
}
|
||||
|
||||
void check_compatible_type(PyVar obj, Type type) {
|
||||
if(!isinstance(obj, type)) { TypeError(type, _tp(obj)); }
|
||||
}
|
||||
|
||||
Type _tp(PyVar obj) { return obj.type; }
|
||||
|
||||
Type _tp(PyVar obj){ return obj.type; }
|
||||
const PyTypeInfo* _tp_info(PyVar obj) { return &_all_types[_tp(obj)]; }
|
||||
|
||||
const PyTypeInfo* _tp_info(Type type) { return &_all_types[type]; }
|
||||
|
||||
PyObject* _t(PyVar obj) { return _all_types[_tp(obj)].obj; }
|
||||
|
||||
PyObject* _t(Type type) { return _all_types[type].obj; }
|
||||
PyObject* _t(PyVar obj){ return _all_types[_tp(obj)].obj; }
|
||||
PyObject* _t(Type type){ return _all_types[type].obj; }
|
||||
|
||||
// equivalent to `obj == NotImplemented` but faster
|
||||
static bool is_not_implemented(PyVar obj) { return obj.type == tp_not_implemented; }
|
||||
static bool is_not_implemented(PyVar obj){ return obj.type == tp_not_implemented; }
|
||||
#endif
|
||||
|
||||
#if PK_REGION("User Type Registration")
|
||||
PyObject* new_module(Str name, Str package = "");
|
||||
PyObject* new_type_object(PyObject* mod, StrName name, Type base, bool subclass_enabled, PyTypeInfo::Vt vt = {});
|
||||
PyObject* new_module(Str name, Str package="");
|
||||
PyObject* new_type_object(PyObject* mod, StrName name, Type base, bool subclass_enabled, PyTypeInfo::Vt vt={});
|
||||
|
||||
template <typename T>
|
||||
PyObject* new_type_object(PyObject* mod, StrName name, Type base, bool subclass_enabled) {
|
||||
template<typename T>
|
||||
PyObject* new_type_object(PyObject* mod, StrName name, Type base, bool subclass_enabled){
|
||||
return new_type_object(mod, name, base, subclass_enabled, PyTypeInfo::Vt::get<T>());
|
||||
}
|
||||
|
||||
template <typename T>
|
||||
Type _tp_user() {
|
||||
return _find_type_in_cxx_typeid_map<T>();
|
||||
}
|
||||
template<typename T>
|
||||
Type _tp_user(){ return _find_type_in_cxx_typeid_map<T>(); }
|
||||
template<typename T>
|
||||
bool is_user_type(PyVar obj){ return _tp(obj) == _tp_user<T>(); }
|
||||
|
||||
template <typename T>
|
||||
bool is_user_type(PyVar obj) {
|
||||
return _tp(obj) == _tp_user<T>();
|
||||
}
|
||||
template<typename T>
|
||||
PyObject* register_user_class(PyObject*, StrName, RegisterFunc, Type base=tp_object, bool subclass_enabled=false);
|
||||
template<typename T>
|
||||
PyObject* register_user_class(PyObject*, StrName, Type base=tp_object, bool subclass_enabled=false);
|
||||
|
||||
template <typename T>
|
||||
PyObject*
|
||||
register_user_class(PyObject*, StrName, RegisterFunc, Type base = tp_object, bool subclass_enabled = false);
|
||||
template <typename T>
|
||||
PyObject* register_user_class(PyObject*, StrName, Type base = tp_object, bool subclass_enabled = false);
|
||||
|
||||
template <typename T, typename... Args>
|
||||
PyVar new_user_object(Args&&... args) {
|
||||
template<typename T, typename ...Args>
|
||||
PyVar new_user_object(Args&&... args){
|
||||
return new_object<T>(_tp_user<T>(), std::forward<Args>(args)...);
|
||||
}
|
||||
|
||||
template <typename T, typename... Args>
|
||||
PyVar new_object(Type type, Args&&... args) {
|
||||
if constexpr(is_sso_v<T>) {
|
||||
return PyVar(type, T(std::forward<Args>(args)...));
|
||||
} else {
|
||||
return heap.gcnew<T>(type, std::forward<Args>(args)...);
|
||||
}
|
||||
template<typename T, typename ...Args>
|
||||
PyVar new_object(Type type, Args&&... args){
|
||||
if constexpr(is_sso_v<T>) return PyVar(type, T(std::forward<Args>(args)...));
|
||||
else return heap.gcnew<T>(type, std::forward<Args>(args)...);
|
||||
}
|
||||
|
||||
template <typename T, typename... Args>
|
||||
void new_stack_object(Type type, Args&&... args) {
|
||||
template<typename T, typename ...Args>
|
||||
void new_stack_object(Type type, Args&&... args){
|
||||
static_assert(std::is_same_v<T, std::decay_t<T>>);
|
||||
static_assert(std::is_trivially_destructible_v<T>);
|
||||
PyObject* p = new (__stack_alloc(py_sizeof<T>)) PyObject(type);
|
||||
PyObject* p = new(__stack_alloc(py_sizeof<T>)) PyObject(type);
|
||||
p->placement_new<T>(std::forward<Args>(args)...);
|
||||
vm->s_data.emplace(p->type, p);
|
||||
}
|
||||
#endif
|
||||
// clang-format on
|
||||
// clang-format on
|
||||
|
||||
template <typename T>
|
||||
Type _find_type_in_cxx_typeid_map() {
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user