summaryrefslogtreecommitdiff
path: root/Libraries/LibJS/Interpreter.h
blob: 6c2beecd9ece71cd8309d9a3383bf67575415a98 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
/*
 * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#include <AK/HashMap.h>
#include <AK/String.h>
#include <AK/FlyString.h>
#include <AK/Vector.h>
#include <LibJS/Forward.h>
#include <LibJS/Heap/Heap.h>
#include <LibJS/Runtime/Value.h>

namespace JS {

enum class ScopeType {
    None,
    Function,
    Block,
    Try,
};

struct Variable {
    Value value;
    DeclarationType declaration_type;
};

struct ScopeFrame {
    ScopeType type;
    NonnullRefPtr<ScopeNode> scope_node;
    HashMap<FlyString, Variable> variables;
};

struct CallFrame {
    Value this_value;
    Vector<Value> arguments;
};

struct Argument {
    FlyString name;
    Value value;
};

class Interpreter {
public:
    Interpreter();
    ~Interpreter();

    Value run(const Statement&, Vector<Argument> = {}, ScopeType = ScopeType::Block);

    Object& global_object() { return *m_global_object; }
    const Object& global_object() const { return *m_global_object; }

    Heap& heap() { return m_heap; }

    void unwind(ScopeType type) { m_unwind_until = type; }

    Value get_variable(const FlyString& name);
    void set_variable(const FlyString& name, Value, bool first_assignment = false);
    void declare_variable(const FlyString& name, DeclarationType);

    void gather_roots(Badge<Heap>, HashTable<Cell*>&);

    void enter_scope(const ScopeNode&, Vector<Argument>, ScopeType);
    void exit_scope(const ScopeNode&);

    Value call(Function*, Value this_value, const Vector<Value>& arguments);

    CallFrame& push_call_frame()
    {
        m_call_stack.append({ js_undefined(), {} });
        return m_call_stack.last();
    }
    void pop_call_frame() { m_call_stack.take_last(); }
    Value this_value() const
    {
        if (m_call_stack.is_empty())
            return m_global_object;
        return m_call_stack.last().this_value;
    }

    Object* string_prototype() { return m_string_prototype; }
    Object* object_prototype() { return m_object_prototype; }
    Object* array_prototype() { return m_array_prototype; }
    Object* error_prototype() { return m_error_prototype; }

    Error* exception() { return m_exception; }
    void clear_exception() { m_exception = nullptr; }
    Value throw_exception(Error*);

private:
    Heap m_heap;

    Vector<ScopeFrame> m_scope_stack;
    Vector<CallFrame> m_call_stack;

    Object* m_global_object { nullptr };
    Object* m_string_prototype { nullptr };
    Object* m_object_prototype { nullptr };
    Object* m_array_prototype { nullptr };
    Object* m_error_prototype { nullptr };

    Error* m_exception { nullptr };

    ScopeType m_unwind_until { ScopeType::None };
};

}