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// -*- c-basic-offset: 2 -*-
/*
* This file is part of the KDE libraries
* Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
* Copyright (C) 2003 Apple Computer, Inc.
*
* 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 _KJSLOOKUP_H_
#define _KJSLOOKUP_H_
#include "identifier.h"
#include "value.h"
#include "object.h"
#include "interpreter.h"
#include <stdio.h>
namespace KJS {
/**
* An entry in a hash table.
*/
struct HashEntry {
/**
* s is the offset to the string key (e.g. a property name)
*/
unsigned short soffset;
/**
* value is the result value (usually an enum value)
*/
short int 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
*/
unsigned char params;
/**
* next is the index to the next entry for the same hash value
*/
short 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 *const entries;
/**
* the maximum value for the hash. Always smaller than size.
*/
int hashSize;
/**
* pointer to the string table.
*/
const char* const sbase;
};
/**
* @short Fast keyword lookup.
*/
class KJS_EXPORT 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 *table, const Identifier &s);
static int find(const struct HashTable *table,
const UChar *c, 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 *table,
const Identifier &s);
static const HashEntry* findEntry(const struct HashTable *table,
const UChar *c, unsigned int len);
/**
* Calculate the hash value for a given key
*/
static unsigned int hash(const Identifier &key);
static unsigned int hash(const UChar *c, unsigned int len);
static unsigned int hash(const char *s);
};
class ExecState;
class UString;
/**
* @internal
* Helper for lookupFunction and lookupValueOrFunction
*/
template <class FuncImp>
inline Value lookupOrCreateFunction(ExecState *exec, const Identifier &propertyName,
const ObjectImp *thisObj, int token, int params, int attr)
{
// Look for cached value in dynamic map of properties (in ObjectImp)
ValueImp * cachedVal = thisObj->ObjectImp::getDirect(propertyName);
/*if (cachedVal)
fprintf(stderr, "lookupOrCreateFunction: Function -> looked up in ObjectImp, found type=%d\n", cachedVal->type());*/
if (cachedVal)
return Value(cachedVal);
ObjectImp* func = new FuncImp( exec, token, params );
Value val( func );
func->setFunctionName( propertyName );
ObjectImp *thatObj = const_cast<ObjectImp *>(thisObj);
thatObj->ObjectImp::put(exec, propertyName, val, attr);
return val;
}
/**
* 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:
* - @c FuncImp the class which implements this object's functions
* - @c ThisImp the class of "this". It must implement the
* getValueProperty(exec,token) method, for non-function properties.
* - @c 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 FuncImp, class ThisImp, class ParentImp>
inline Value lookupGet(ExecState *exec, const Identifier &propertyName,
const HashTable* table, const ThisImp* thisObj)
{
const HashEntry* entry = Lookup::findEntry(table, propertyName);
if (!entry) // not found, forward to parent
return thisObj->ParentImp::get(exec, propertyName);
//fprintf(stderr, "lookupGet: found value=%d attr=%d\n", entry->value, entry->attr);
if (entry->attr & Function)
return lookupOrCreateFunction<FuncImp>(exec, propertyName, thisObj, entry->value, entry->params, entry->attr);
return thisObj->getValueProperty(exec, entry->value);
}
/**
* Simplified version of lookupGet in case there are only functions.
* Using this instead of lookupGet prevents 'this' from implementing a dummy getValueProperty.
*/
template <class FuncImp, class ParentImp>
inline Value lookupGetFunction(ExecState *exec, const Identifier &propertyName,
const HashTable* table, const ObjectImp* thisObj)
{
const HashEntry* entry = Lookup::findEntry(table, propertyName);
if (!entry) // not found, forward to parent
return static_cast<const ParentImp *>(thisObj)->ParentImp::get(exec, propertyName);
if (entry->attr & Function)
return lookupOrCreateFunction<FuncImp>(exec, propertyName, thisObj, entry->value, entry->params, entry->attr);
fprintf(stderr, "Function bit not set! Shouldn't happen in lookupGetFunction!\n" );
return Undefined();
}
/**
* Simplified version of lookupGet in case there are no functions, only "values".
* Using this instead of lookupGet removes the need for a FuncImp class.
*/
template <class ThisImp, class ParentImp>
inline Value lookupGetValue(ExecState *exec, const Identifier &propertyName,
const HashTable* table, const ThisImp* thisObj)
{
const HashEntry* entry = Lookup::findEntry(table, propertyName);
if (!entry) // not found, forward to parent
return thisObj->ParentImp::get(exec, propertyName);
if (entry->attr & Function)
fprintf(stderr, "Function bit set! Shouldn't happen in lookupGetValue! propertyName was %s\n", propertyName.ascii() );
return thisObj->getValueProperty(exec, entry->value);
}
/**
* This one is for "put".
* Lookup hash entry for property to be set, and set the value.
*/
template <class ThisImp, class ParentImp>
inline void lookupPut(ExecState *exec, const Identifier &propertyName,
const Value& value, int attr,
const HashTable* table, ThisImp* thisObj)
{
const HashEntry* entry = Lookup::findEntry(table, propertyName);
if (!entry) // not found: forward to parent
thisObj->ParentImp::put(exec, propertyName, value, attr);
else if (entry->attr & Function) // function: put as override property
thisObj->ObjectImp::put(exec, propertyName, value, attr);
else if (entry->attr & ReadOnly) // readonly! Can't put!
#ifdef KJS_VERBOSE
fprintf(stderr,"WARNING: Attempt to change value of readonly property '%s'\n",propertyName.ascii());
#else
; // do nothing
#endif
else
thisObj->putValueProperty(exec, entry->value, value, attr);
}
/**
* This template method retrieves or create an object that is unique
* (for a given interpreter) The first time this is called (for a given
* property name), the Object will be constructed, and set as a property
* of the interpreter's global object. Later calls will simply retrieve
* that cached object. Note that the object constructor must take 1 argument, exec.
*/
template <class ClassCtor>
inline KJS::Object cacheGlobalObject(ExecState *exec, const Identifier &propertyName)
{
ValueImp *obj = static_cast<KJS::ObjectImp*>(exec->interpreter()->globalObject().imp())->getDirect(propertyName);
if (obj)
return KJS::Object::dynamicCast(Value(obj));
else
{
KJS::Object newObject(new ClassCtor(exec));
exec->interpreter()->globalObject().put(exec, propertyName, newObject, Internal);
return newObject;
}
}
/**
* 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.
* ParentProto 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. "DOMNodeProtoTable"), then
* DEFINE_PROTOTYPE("DOMNode",DOMNodeProto)
* IMPLEMENT_PROTOFUNC(DOMNodeProtoFunc)
* IMPLEMENT_PROTOTYPE(DOMNodeProto,DOMNodeProtoFunc)
* and use DOMNodeProto::self(exec) as prototype in the DOMNode constructor.
* If the prototype has a "parent prototype", e.g. DOMElementProto falls back on DOMNodeProto,
* then the last line will use IMPLEMENT_PROTOTYPE_WITH_PARENT, with DOMNodeProto as last argument.
* PUBLIC_DEFINE_PROTOTYPE and PUBLIC_IMPLEMENT_PROTOTYPE are versions with support for separate compilation
*/
#define PUBLIC_DEFINE_PROTOTYPE(ClassName,ClassProto) \
namespace KJS { \
class ClassProto : public KJS::ObjectImp { \
friend KJS::Object cacheGlobalObject<ClassProto>(KJS::ExecState *exec, const KJS::Identifier &propertyName); \
public: \
static KJS::Object self(KJS::ExecState *exec) \
{ \
return cacheGlobalObject<ClassProto>( exec, "[[" ClassName ".prototype]]" ); \
} \
protected: \
ClassProto( KJS::ExecState *exec ) \
: KJS::ObjectImp( exec->interpreter()->builtinObjectPrototype() ) {} \
\
public: \
virtual const KJS::ClassInfo *classInfo() const { return &info; } \
static const KJS::ClassInfo info; \
KJS::Value get(KJS::ExecState *exec, const KJS::Identifier &propertyName) const; \
bool hasProperty(KJS::ExecState *exec, const KJS::Identifier &propertyName) const; \
}; \
}
#define IMPLEMENT_CLASSINFO(ClassName,ClassProto) \
namespace KJS {\
const KJS::ClassInfo ClassProto::info = { ClassName, 0, &ClassProto##Table, 0 }; \
}
#define DEFINE_PROTOTYPE(ClassName,ClassProto) \
PUBLIC_DEFINE_PROTOTYPE(ClassName,ClassProto) \
IMPLEMENT_CLASSINFO(ClassName,ClassProto)
#define IMPLEMENT_PROTOTYPE(ClassProto,ClassFunc) \
KJS::Value KJS::ClassProto::get(KJS::ExecState *exec, const KJS::Identifier &propertyName) const \
{ \
/*fprintf( stderr, "%sProto::get(%s) [in macro, no parent]\n", info.className, propertyName.ascii());*/ \
return lookupGetFunction<ClassFunc,KJS::ObjectImp>(exec, propertyName, &ClassProto##Table, this ); \
} \
bool KJS::ClassProto::hasProperty(KJS::ExecState *exec, const KJS::Identifier &propertyName) const \
{ /*stupid but we need this to have a common macro for the declaration*/ \
return KJS::ObjectImp::hasProperty(exec, propertyName); \
}
#define PUBLIC_IMPLEMENT_PROTOTYPE(ClassProto,ClassName,ClassFunc) \
IMPLEMENT_PROTOTYPE(ClassProto,ClassFunc)\
IMPLEMENT_CLASSINFO(ClassName,ClassProto)
#define IMPLEMENT_PROTOTYPE_WITH_PARENT(ClassProto,ClassFunc,ParentProto) \
KJS::Value KJS::ClassProto::get(KJS::ExecState *exec, const KJS::Identifier &propertyName) const \
{ \
/*fprintf( stderr, "%sProto::get(%s) [in macro]\n", info.className, propertyName.ascii());*/ \
KJS::Value val = lookupGetFunction<ClassFunc,KJS::ObjectImp>(exec, propertyName, &ClassProto##Table, this ); \
if ( val.type() != UndefinedType ) return val; \
/* Not found -> forward request to "parent" prototype */ \
return ParentProto::self(exec).get( exec, propertyName ); \
} \
bool KJS::ClassProto::hasProperty(KJS::ExecState *exec, const KJS::Identifier &propertyName) const \
{ \
if (KJS::ObjectImp::hasProperty(exec, propertyName)) \
return true; \
return ParentProto::self(exec).hasProperty(exec, propertyName); \
}
#define PUBLIC_IMPLEMENT_PROTOTYPE_WITH_PARENT(ClassProto,ClassName,ClassFunc,ParentProto) \
IMPLEMENT_PROTOTYPE_WITH_PARENT(ClassProto,ClassFunc,ParentProto) \
IMPLEMENT_CLASSINFO(ClassName,ClassProto)
#define IMPLEMENT_PROTOFUNC(ClassFunc) \
namespace KJS { \
class ClassFunc : public ObjectImp { \
public: \
ClassFunc(KJS::ExecState *exec, int i, int len) \
: ObjectImp( /*proto? */ ), id(i) { \
KJS::Value protect(this); \
put(exec,lengthPropertyName,Number(len),DontDelete|ReadOnly|DontEnum); \
} \
virtual bool implementsCall() const { return true; } \
/** You need to implement that one */ \
virtual KJS::Value call(KJS::ExecState *exec, KJS::Object &thisObj, const KJS::List &args); \
private: \
int id; \
}; \
}
// To be used in all call() implementations, before casting the type of thisObj
#define KJS_CHECK_THIS( ClassName, theObj ) \
if (!theObj.isValid() || !theObj.inherits(&ClassName::info)) { \
KJS::UString errMsg = "Attempt at calling a function that expects a "; \
errMsg += ClassName::info.className; \
errMsg += " on a "; \
errMsg += thisObj.className(); \
KJS::Object err = KJS::Error::create(exec, KJS::TypeError, errMsg.ascii()); \
exec->setException(err); \
return err; \
}
/*
* List of things to do when porting an objectimp to the 'static hashtable' mechanism:
* - write the hashtable source, between @begin and @end
* - add a rule to build the .lut.h
* - include the .lut.h
* - mention the table in the classinfo (add a classinfo if necessary)
* - write/update the class enum (for the tokens)
* - turn get() into getValueProperty(), put() into putValueProperty(), using a switch and removing funcs
* - write get() and/or put() using a template method
* - cleanup old stuff (e.g. hasProperty)
* - compile, test, commit ;)
*/
} // namespace
#endif
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