1 // -*- c-basic-offset: 2 -*-
3 * This file is part of the KDE libraries
4 * Copyright (C) 1999-2001 Harri Porten (porten@kde.org)
5 * Copyright (C) 2001 Peter Kelly (pmk@post.com)
6 * Copyright (C) 2003, 2006 Apple Computer, Inc.
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Library General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Library General Public License for more details.
18 * You should have received a copy of the GNU Library General Public License
19 * along with this library; see the file COPYING.LIB. If not, write to
20 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
21 * Boston, MA 02110-1301, USA.
33 class FunctionBodyNode
;
36 * @short Execution context.
38 * Represents an execution context, as specified by section 10 of the ECMA
41 * An execution context contains information about the current state of the
42 * script - the scope for variable lookup, the value of "this", etc. A new
43 * execution context is entered whenever global code is executed (e.g. with
44 * Interpreter::evaluate()), a function is called (see
45 * Object::call()), or the builtin "eval" function is executed.
47 * Most inheritable functions in the KJS api take a ExecState pointer as
48 * their first parameter. This can be used to obtain a handle to the current
51 class KJS_EXPORT Context
{
53 Context(JSObject
* global
, Interpreter
*, JSObject
* thisV
,
54 FunctionBodyNode
* currentBody
, CodeType type
= GlobalCode
,
55 Context
* callingContext
= 0, FunctionImp
* function
= 0, const List
* args
= 0);
59 * Returns the scope chain for this execution context. This is used for
60 * variable lookup, with the list being searched from start to end until a
63 * @return The execution context's scope chain
65 const ScopeChain
& scopeChain() const { return scope
; }
68 * Returns the variable object for the execution context. This contains a
69 * property for each variable declared in the execution context.
71 * @return The execution context's variable object
73 JSObject
* variableObject() const { return m_variable
; }
74 void setVariableObject(JSObject
* v
) { m_variable
= v
; }
77 * Returns the "this" value for the execution context. This is the value
78 * returned when a script references the special variable "this". It should
79 * always be an Object, unless application-specific code has passed in a
82 * The object that is used as the "this" value depends on the type of
83 * execution context - for global contexts, the global object is used. For
84 * function objewcts, the value is given by the caller (e.g. in the case of
85 * obj.func(), obj would be the "this" value). For code executed by the
86 * built-in "eval" function, the this value is the same as the calling
89 * @return The execution context's "this" value
91 JSObject
* thisValue() const { return m_thisVal
; }
94 * Returns the context from which the current context was invoked. For
95 * global code this will be a null context (i.e. one for which
96 * isNull() returns true). You should check isNull() on the returned
97 * value before calling any of it's methods.
99 * @return The calling execution context
101 Context
* callingContext() { return m_callingContext
; }
103 JSObject
* activationObject() { return m_activation
; }
104 CodeType
codeType() { return m_codeType
; }
105 FunctionBodyNode
* currentBody() { return m_currentBody
; }
106 FunctionImp
* function() const { return m_function
; }
107 const List
* arguments() const { return m_arguments
; }
109 void pushScope(JSObject
* s
) { scope
.push(s
); }
110 void popScope() { scope
.pop(); }
115 // Contexts are always stack-allocated, and the garbage collector
116 // marks the stack, so we don't need to protect the objects below from GC.
118 Interpreter
* m_interpreter
;
119 Context
* m_callingContext
;
120 FunctionBodyNode
* m_currentBody
;
122 FunctionImp
* m_function
;
123 const List
* m_arguments
;
124 JSObject
* m_activation
;
127 JSObject
* m_variable
;