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// -*- c-basic-offset: 2 -*-
/*
* Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
* Copyright (C) 2003, 2006, 2007 Apple Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#ifndef KJS_lookup_h
#define KJS_lookup_h
#include "ExecState.h"
#include "function.h"
#include "identifier.h"
#include "JSGlobalObject.h"
#include "object.h"
#include <stdio.h>
#include <wtf/Assertions.h>
namespace KJS {
/**
* An entry in a hash table.
*/
struct HashEntry {
/**
* s is the key (e.g. a property name)
*/
const char* s;
/**
* value is the result value (enum value for properties and a function pointer to a constructor factory for functions)
*/
union {
intptr_t intValue;
PrototypeFunction::JSMemberFunction functionValue;
} value;
/**
* attr is a set for flags (e.g. the property flags, see object.h)
*/
unsigned char attr;
/**
* params is another number. For property hashtables, it is used to
* denote the number of argument of the function
*/
short int params;
/**
* next is the pointer to the next entry for the same hash value
*/
const HashEntry* next;
};
/**
* A hash table
* Usually the hashtable is generated by the create_hash_table script, from a .table file.
*
* The implementation uses an array of entries, "size" is the total size of that array.
* The entries between 0 and hashSize-1 are the entry points
* for each hash value, and the entries between hashSize and size-1
* are the overflow entries for the hash values that need one.
* The "next" pointer of the entry links entry points to overflow entries,
* and links overflow entries between them.
*/
struct HashTable {
/**
* type is a version number. Currently always 2
*/
int type;
/**
* size is the total number of entries in the hashtable, including the null entries,
* i.e. the size of the "entries" array.
* Used to iterate over all entries in the table
*/
int size;
/**
* pointer to the array of entries
* Mind that some entries in the array are null (0,0,0,0).
*/
const HashEntry* entries;
/**
* the maximum value for the hash minus 1. Always smaller than size.
*/
int hashSizeMask;
};
/**
* @short Fast keyword lookup.
*/
class Lookup {
public:
/**
* Find an entry in the table, and return its value (i.e. the value field of HashEntry)
*/
static int find(const struct HashTable*, const Identifier&);
static int find(const struct HashTable*, const UChar*, unsigned int len);
/**
* Find an entry in the table, and return the entry
* This variant gives access to the other attributes of the entry,
* especially the attr field.
*/
static const HashEntry* findEntry(const struct HashTable*, const Identifier&);
};
class ExecState;
class UString;
/**
* @internal
* Helper for getStaticFunctionSlot and getStaticPropertySlot
*/
inline JSValue* staticFunctionGetter(ExecState* exec, JSObject*, const Identifier& propertyName, const PropertySlot& slot)
{
// Look for cached value in dynamic map of properties (in JSObject)
JSObject* thisObj = slot.slotBase();
JSValue* cachedVal = thisObj->getDirect(propertyName);
if (cachedVal)
return cachedVal;
const HashEntry* entry = slot.staticEntry();
JSValue* val = new PrototypeFunction(exec, entry->params, propertyName, entry->value.functionValue);
thisObj->putDirect(propertyName, val, entry->attr);
return val;
}
/**
* @internal
* Helper for getStaticValueSlot and getStaticPropertySlot
*/
template <class ThisImp>
inline JSValue* staticValueGetter(ExecState* exec, JSObject*, const Identifier&, const PropertySlot& slot)
{
ThisImp* thisObj = static_cast<ThisImp*>(slot.slotBase());
const HashEntry* entry = slot.staticEntry();
return thisObj->getValueProperty(exec, entry->value.intValue);
}
/**
* Helper method for property lookups
*
* This method does it all (looking in the hashtable, checking for function
* overrides, creating the function or retrieving from cache, calling
* getValueProperty in case of a non-function property, forwarding to parent if
* unknown property).
*
* Template arguments:
* @param FuncImp the class which implements this object's functions
* @param ThisImp the class of "this". It must implement the getValueProperty(exec,token) method,
* for non-function properties.
* @param ParentImp the class of the parent, to propagate the lookup.
*
* Method arguments:
* @param exec execution state, as usual
* @param propertyName the property we're looking for
* @param table the static hashtable for this class
* @param thisObj "this"
*/
template <class ThisImp, class ParentImp>
inline bool getStaticPropertySlot(ExecState* exec, const HashTable* table,
ThisImp* thisObj, const Identifier& propertyName, PropertySlot& slot)
{
const HashEntry* entry = Lookup::findEntry(table, propertyName);
if (!entry) // not found, forward to parent
return thisObj->ParentImp::getOwnPropertySlot(exec, propertyName, slot);
if (entry->attr & Function)
slot.setStaticEntry(thisObj, entry, staticFunctionGetter);
else
slot.setStaticEntry(thisObj, entry, staticValueGetter<ThisImp>);
return true;
}
/**
* Simplified version of getStaticPropertySlot in case there are only functions.
* Using this instead of getStaticPropertySlot allows 'this' to avoid implementing
* a dummy getValueProperty.
*/
template <class ParentImp>
inline bool getStaticFunctionSlot(ExecState* exec, const HashTable* table,
JSObject* thisObj, const Identifier& propertyName, PropertySlot& slot)
{
const HashEntry* entry = Lookup::findEntry(table, propertyName);
if (!entry) // not found, forward to parent
return static_cast<ParentImp*>(thisObj)->ParentImp::getOwnPropertySlot(exec, propertyName, slot);
ASSERT(entry->attr & Function);
slot.setStaticEntry(thisObj, entry, staticFunctionGetter);
return true;
}
/**
* Simplified version of getStaticPropertySlot in case there are no functions, only "values".
* Using this instead of getStaticPropertySlot removes the need for a FuncImp class.
*/
template <class ThisImp, class ParentImp>
inline bool getStaticValueSlot(ExecState* exec, const HashTable* table,
ThisImp* thisObj, const Identifier& propertyName, PropertySlot& slot)
{
const HashEntry* entry = Lookup::findEntry(table, propertyName);
if (!entry) // not found, forward to parent
return thisObj->ParentImp::getOwnPropertySlot(exec, propertyName, slot);
ASSERT(!(entry->attr & Function));
slot.setStaticEntry(thisObj, entry, staticValueGetter<ThisImp>);
return true;
}
/**
* This one is for "put".
* It looks up a hash entry for the property to be set. If an entry
* is found it sets the value and returns true, else it returns false.
*/
template <class ThisImp>
inline bool lookupPut(ExecState* exec, const Identifier& propertyName,
JSValue* value, int attr,
const HashTable* table, ThisImp* thisObj)
{
const HashEntry* entry = Lookup::findEntry(table, propertyName);
if (!entry)
return false;
if (entry->attr & Function) // function: put as override property
thisObj->JSObject::put(exec, propertyName, value, attr);
else if (!(entry->attr & ReadOnly))
thisObj->putValueProperty(exec, entry->value.intValue, value, attr);
return true;
}
/**
* This one is for "put".
* It calls lookupPut<ThisImp>() to set the value. If that call
* returns false (meaning no entry in the hash table was found),
* then it calls put() on the ParentImp class.
*/
template <class ThisImp, class ParentImp>
inline void lookupPut(ExecState* exec, const Identifier& propertyName,
JSValue* value, int attr,
const HashTable* table, ThisImp* thisObj)
{
if (!lookupPut<ThisImp>(exec, propertyName, value, attr, table, thisObj))
thisObj->ParentImp::put(exec, propertyName, value, attr); // not found: forward to parent
}
/**
* This template method retrieves or create an object that is unique
* (for a given global object) The first time this is called (for a given
* property name), the Object will be constructed, and set as a property
* of the global object. Later calls will simply retrieve that cached object.
* Note that the object constructor must take 1 argument, exec.
*/
template <class ClassCtor>
inline JSObject* cacheGlobalObject(ExecState* exec, const Identifier& propertyName)
{
JSGlobalObject* globalObject = exec->lexicalGlobalObject();
JSValue* obj = globalObject->getDirect(propertyName);
if (obj) {
ASSERT(obj->isObject());
return static_cast<JSObject* >(obj);
}
JSObject* newObject = new ClassCtor(exec);
globalObject->putDirect(propertyName, newObject, Internal | DontEnum);
return newObject;
}
} // namespace
/**
* Helpers to define prototype objects (each of which simply implements
* the functions for a type of objects).
* Sorry for this not being very readable, but it actually saves much copy-n-paste.
* ParentPrototype is not our base class, it's the object we use as fallback.
* The reason for this is that there should only be ONE DOMNode.hasAttributes (e.g.),
* not one in each derived class. So we link the (unique) prototypes between them.
*
* Using those macros is very simple: define the hashtable (e.g. "DOMNodePrototypeTable"), then
* KJS_DEFINE_PROTOTYPE(DOMNodePrototype)
* KJS_IMPLEMENT_PROTOTYPE("DOMNode", DOMNodePrototype, DOMNodePrototypeFunction)
* and use DOMNodePrototype::self(exec) as prototype in the DOMNode constructor.
* If the prototype has a "parent prototype", e.g. DOMElementPrototype falls back on DOMNodePrototype,
* then the first line will use KJS_DEFINE_PROTOTYPE_WITH_PROTOTYPE, with DOMNodePrototype as the second argument.
*/
// These macros assume that a prototype's only properties are functions
#define KJS_DEFINE_PROTOTYPE(ClassPrototype) \
class ClassPrototype : public KJS::JSObject { \
public: \
static KJS::JSObject* self(KJS::ExecState* exec); \
virtual const KJS::ClassInfo* classInfo() const { return &info; } \
static const KJS::ClassInfo info; \
bool getOwnPropertySlot(KJS::ExecState* , const KJS::Identifier&, KJS::PropertySlot&); \
ClassPrototype(KJS::ExecState* exec) \
: KJS::JSObject(exec->lexicalGlobalObject()->objectPrototype()) { } \
\
};
#define KJS_DEFINE_PROTOTYPE_WITH_PROTOTYPE(ClassPrototype, ClassPrototypePrototype) \
class ClassPrototype : public KJS::JSObject { \
public: \
static KJS::JSObject* self(KJS::ExecState* exec); \
virtual const KJS::ClassInfo* classInfo() const { return &info; } \
static const KJS::ClassInfo info; \
bool getOwnPropertySlot(KJS::ExecState*, const KJS::Identifier&, KJS::PropertySlot&); \
ClassPrototype(KJS::ExecState* exec) \
: KJS::JSObject(ClassPrototypePrototype::self(exec)) { } \
\
};
#define KJS_IMPLEMENT_PROTOTYPE(ClassName, ClassPrototype) \
const ClassInfo ClassPrototype::info = { ClassName"Prototype", 0, &ClassPrototype##Table }; \
JSObject* ClassPrototype::self(ExecState* exec) \
{ \
static Identifier* prototypeIdentifier = new Identifier("[[" ClassName ".prototype]]"); \
return KJS::cacheGlobalObject<ClassPrototype>(exec, *prototypeIdentifier); \
} \
bool ClassPrototype::getOwnPropertySlot(ExecState* exec, const Identifier& propertyName, PropertySlot& slot) \
{ \
return getStaticFunctionSlot<JSObject>(exec, &ClassPrototype##Table, this, propertyName, slot); \
}
#endif // KJS_lookup_h