kjs/ExecState.h

   1 // -*- mode: c++; c-basic-offset: 4 -*-
   2 /*
   3  *  Copyright (C) 1999-2001 Harri Porten (porten@kde.org)
   4  *  Copyright (C) 2001 Peter Kelly (pmk@post.com)
   5  *  Copyright (C) 2003, 2007, 2008 Apple Inc. All rights reserved.
   6  *
   7  *  This library is free software; you can redistribute it and/or
   8  *  modify it under the terms of the GNU Library General Public
   9  *  License as published by the Free Software Foundation; either
  10  *  version 2 of the License, or (at your option) any later version.
  11  *
  12  *  This library is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  *  Library General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU Library General Public License
  18  *  along with this library; see the file COPYING.LIB.  If not, write to
  19  *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20  *  Boston, MA 02110-1301, USA.
  21  *
  22  */
  23
  24 #ifndef ExecState_h
  25 #define ExecState_h
  26
  27 #include "LabelStack.h"
  28 #include "LocalStorage.h"
  29 #include "completion.h"
  30 #include "list.h"
  31 #include "scope_chain.h"
  32
  33 namespace KJS  {
  34
  35     class ActivationImp;
  36     class CommonIdentifiers;
  37     class EvalNode;
  38     class FunctionBodyNode;
  39     class FunctionImp;
  40     class GlobalFuncImp;
  41     class Interpreter;
  42     class JSGlobalObject;
  43     class JSVariableObject;
  44     class ProgramNode;
  45     class ScopeNode;
  46
  47     enum CodeType { GlobalCode, EvalCode, FunctionCode };
  48
  49     typedef Vector<ExecState*, 16> ExecStateStack;
  50
  51     // Represents the current state of script execution.
  52     // Passed as the first argument to most functions.
  53     class ExecState : Noncopyable {
  54     public:
  55         // Global object that was in scope when the current script started executing.
  56         JSGlobalObject* dynamicGlobalObject() const { return m_globalObject; }
  57
  58         // Global object that was in scope when the current body of code was defined.
  59         JSGlobalObject* lexicalGlobalObject() const;
  60
  61         void setException(JSValue* e) { m_exception = e; }
  62         void clearException() { m_exception = 0; }
  63         JSValue* exception() const { return m_exception; }
  64         JSValue** exceptionSlot() { return &m_exception; }
  65         bool hadException() const { return !!m_exception; }
  66
  67         const ScopeChain& scopeChain() const { return m_scopeChain; }
  68         void pushScope(JSObject* s) { m_scopeChain.push(s); }
  69         void popScope() { m_scopeChain.pop(); }
  70         void replaceScopeChainTop(JSObject* o) { m_scopeChain.replaceTop(o); }
  71
  72         JSVariableObject* variableObject() const { return m_variableObject; }
  73         void setVariableObject(JSVariableObject* v) { m_variableObject = v; }
  74
  75         JSObject* thisValue() const { return m_thisValue; }
  76
  77         ExecState* callingExecState() { return m_callingExec; }
  78
  79         ActivationImp* activationObject() { return m_activation; }
  80         void setActivationObject(ActivationImp* a) { m_activation = a; }
  81         CodeType codeType() { return m_codeType; }
  82         ScopeNode* scopeNode() { return m_scopeNode; }
  83         FunctionImp* function() const { return m_function; }
  84         const List* arguments() const { return m_arguments; }
  85
  86         LabelStack& seenLabels() { return m_labelStack; }
  87
  88         void pushIteration() { m_iterationDepth++; }
  89         void popIteration() { m_iterationDepth--; }
  90         bool inIteration() const { return (m_iterationDepth > 0); }
  91
  92         void pushSwitch() { m_switchDepth++; }
  93         void popSwitch() { m_switchDepth--; }
  94         bool inSwitch() const { return (m_switchDepth > 0); }
  95
  96         // These pointers are used to avoid accessing global variables for these,
  97         // to avoid taking PIC branches in Mach-O binaries.
  98         const CommonIdentifiers& propertyNames() const { return *m_propertyNames; }
  99         const List& emptyList() const { return *m_emptyList; }
 100
 101         LocalStorage& localStorage() { return *m_localStorage; }
 102         void setLocalStorage(LocalStorage* s) { m_localStorage = s; }
 103
 104         // These are only valid right after calling execute().
 105         ComplType completionType() const { return m_completionType; }
 106         const Identifier& breakOrContinueTarget() const
 107         {
 108             ASSERT(m_completionType == Break || m_completionType == Continue);
 109             return *m_breakOrContinueTarget;
 110         }
 111
 112         // Only for use in the implementation of execute().
 113         void setCompletionType(ComplType type)
 114         {
 115             ASSERT(type != Break);
 116             ASSERT(type != Continue);
 117             m_completionType = type;
 118         }
 119         JSValue* setNormalCompletion()
 120         {
 121             ASSERT(!hadException());
 122             m_completionType = Normal;
 123             return 0;
 124         }
 125         JSValue* setNormalCompletion(JSValue* value)
 126         {
 127             ASSERT(!hadException());
 128             m_completionType = Normal;
 129             return value;
 130         }
 131         JSValue* setBreakCompletion(const Identifier* target)
 132         {
 133             ASSERT(!hadException());
 134             m_completionType = Break;
 135             m_breakOrContinueTarget = target;
 136             return 0;
 137         }
 138         JSValue* setContinueCompletion(const Identifier* target)
 139         {
 140             ASSERT(!hadException());
 141             m_completionType = Continue;
 142             m_breakOrContinueTarget = target;
 143             return 0;
 144         }
 145         JSValue* setReturnValueCompletion(JSValue* returnValue)
 146         {
 147             ASSERT(!hadException());
 148             ASSERT(returnValue);
 149             m_completionType = ReturnValue;
 150             return returnValue;
 151         }
 152         JSValue* setThrowCompletion(JSValue* exception)
 153         {
 154             ASSERT(!hadException());
 155             ASSERT(exception);
 156             m_completionType = Throw;
 157             return exception;
 158         }
 159         JSValue* setInterruptedCompletion()
 160         {
 161             ASSERT(!hadException());
 162             m_completionType = Interrupted;
 163             return 0;
 164         }
 165         JSValue* setInterruptedCompletion(JSValue* returnValue)
 166         {
 167             ASSERT(!hadException());
 168             ASSERT(returnValue);
 169             m_completionType = Interrupted;
 170             return returnValue;
 171         }
 172
 173         static void markActiveExecStates();
 174         static ExecStateStack& activeExecStates();
 175
 176     protected:
 177         ExecState(JSGlobalObject*);
 178         ExecState(JSGlobalObject*, JSObject* thisObject, ProgramNode*);
 179         ExecState(JSGlobalObject*, EvalNode*, ExecState* callingExecState);
 180         ExecState(JSGlobalObject*, JSObject* thisObject, FunctionBodyNode*,
 181             ExecState* callingExecState, FunctionImp*, const List& args);
 182         ~ExecState();
 183
 184         // ExecStates are always stack-allocated, and the garbage collector
 185         // marks the stack, so we don't need to protect the objects below from GC.
 186
 187         JSGlobalObject* m_globalObject;
 188         JSValue* m_exception;
 189         CommonIdentifiers* m_propertyNames;
 190         const List* m_emptyList;
 191
 192         ExecState* m_callingExec;
 193
 194         ScopeNode* m_scopeNode;
 195
 196         FunctionImp* m_function;
 197         const List* m_arguments;
 198         ActivationImp* m_activation;
 199         LocalStorage* m_localStorage;
 200
 201         ScopeChain m_scopeChain;
 202         JSVariableObject* m_variableObject;
 203         JSObject* m_thisValue;
 204
 205         LabelStack m_labelStack;
 206         int m_iterationDepth;
 207         int m_switchDepth;
 208         CodeType m_codeType;
 209
 210         ComplType m_completionType;
 211         const Identifier* m_breakOrContinueTarget;
 212     };
 213
 214     class GlobalExecState : public ExecState {
 215     public:
 216         GlobalExecState(JSGlobalObject*);
 217         ~GlobalExecState();
 218     };
 219
 220     class InterpreterExecState : public ExecState {
 221     public:
 222         InterpreterExecState(JSGlobalObject*, JSObject* thisObject, ProgramNode*);
 223         ~InterpreterExecState();
 224     };
 225
 226     class EvalExecState : public ExecState {
 227     public:
 228         EvalExecState(JSGlobalObject*, EvalNode*, ExecState* callingExecState);
 229         ~EvalExecState();
 230     };
 231
 232     class FunctionExecState : public ExecState {
 233     public:
 234         FunctionExecState(JSGlobalObject*, JSObject* thisObject, FunctionBodyNode*,
 235             ExecState* callingExecState, FunctionImp*, const List& args);
 236         ~FunctionExecState();
 237     };
 238
 239 } // namespace KJS
 240
 241 #endif // ExecState_h