TObject

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http://hi.baidu.com/fefesoft/item/e08767f158725b08d89e72d9

TObject = class

//创建
constructor Create;
//释放
procedure Free;
//初始化实列
class function InitInstance(Instance: Pointer): TObject;
//清除实列
procedure CleanupInstance;
//获得类的类型
function ClassType: TClass;
//获得了的名称
class function ClassName: ShortString;
//判断类的名称
class function ClassNameIs(const Name: string): Boolean;
//类的父类
class function ClassParent: TClass;
//类的信息指针
class function ClassInfo: Pointer;
//当前类的实列大小
class function InstanceSize: Longint;
//判断是否从一个类继承下来
class function InheritsFrom(AClass: TClass): Boolean;
//根据方法的名称获得方法的地址
class function MethodAddress(const Name: ShortString): Pointer;
//根据地址或的方法的名称
class function MethodName(Address: Pointer): ShortString;
//根据名称获得属性的地址
function FieldAddress(const Name: ShortString): Pointer;
//查询接口
function GetInterface(const IID: TGUID; out Obj): Boolean;
//获得接口的入口
class function GetInterfaceEntry(const IID: TGUID): PInterfaceEntry;
//获得接口表
class function GetInterfaceTable: PInterfaceTable;
//安全调用例外
function SafeCallException(ExceptObject: TObject;
ExceptAddr: Pointer): HResult; virtual;
//创建之后的执行
procedure AfterConstruction; virtual;
//释放之前的执行
procedure BeforeDestruction; virtual;
//分派消息
procedure Dispatch(var Message); virtual;
//默认的句柄
procedure DefaultHandler(var Message); virtual;
//新的实列
class function NewInstance: TObject; virtual;
//释放实列
procedure FreeInstance; virtual;
//释放
destructor Destroy; virtual;
end;

//初始化实列
class function TObject.InitInstance(Instance: Pointer): TObject;
{$IFDEF PUREPASCAL}
var
IntfTable: PInterfaceTable;
ClassPtr: TClass;
I: Integer;
begin
//分配需要的内存的大小
FillChar(Instance^, InstanceSize, 0);
//实列化分配好的内存
PInteger(Instance)^ := Integer(Self);
ClassPtr := Self;
//如果成功
while ClassPtr <> nil do
begin
//获得接口表
IntfTable := ClassPtr.GetInterfaceTable;
//遍历接口
if IntfTable <> nil then
for I := 0 to IntfTable.EntryCount-1 do
//初始化每个接口函数的具体实现
with IntfTable.Entries[I] do
begin
if VTable <> nil then
PInteger(@PChar(Instance)[IOffset])^ := Integer(VTable);
end;
ClassPtr := ClassPtr.ClassParent;
end;
Result := Instance;
end;

//清除实列
procedure TObject.CleanupInstance;
{$IFDEF PUREPASCAL}
var
ClassPtr: TClass;
InitTable: Pointer;
begin
//获得当前的类型
ClassPtr := ClassType;
//获得初始化标的地址
InitTable := PPointer(Integer(ClassPtr) + vmtInitTable)^;
//如果当前类存在并且初始化表也存在
while (ClassPtr <> nil) and (InitTable <> nil) do
begin
//释放所有的信息
_FinalizeRecord(Self, InitTable);
//如果当前类有父类则清楚父类的信息
ClassPtr := ClassPtr.ClassParent;
if ClassPtr <> nil then
InitTable := PPointer(Integer(ClassPtr) + vmtInitTable)^;
end;
end;

//获得当前类的类型
function TObject.ClassType: TClass;
begin
//就是返回当前类的指针
Pointer(Result) := PPointer(Self)^;
end;

//获得当前类的类名
class function TObject.ClassName: ShortString;
{$IFDEF PUREPASCAL}
begin
//根据虚拟方发表返回指定的地址
Result := PShortString(PPointer(Integer(Self) + vmtClassName)^)^;
end;

// 判断当前类的类名
class function TObject.ClassNameIs(const Name: string): Boolean;
{$IFDEF PUREPASCAL}
var
Temp: ShortString;
I: Byte;
begin
Result := False;
//获得当前类的类名得指针
Temp := ClassName;
//根据字符串的长度比较每个字符区分大小写
for I := 0 to Byte(Temp[0]) do
if Temp[I] <> Name[I] then Exit;
Result := True;
end;

//获得当前类的父类
class function TObject.ClassParent: TClass;
{$IFDEF PUREPASCAL}
begin
//根据虚拟方法表或的父的地址指针
Pointer(Result) := PPointer(Integer(Self) + vmtParent)^;
//如果存在父类则返回
if Result <> nil then
Pointer(Result) := PPointer(Result)^;
end;
{$ELSE}
asm
MOV EAX,[EAX].vmtParent
TEST EAX,EAX
JE @@exit
MOV EAX,[EAX]
@@exit:
end;

//获得类型信息
class function TObject.ClassInfo: Pointer;
begin
Result := PPointer(Integer(Self) + vmtTypeInfo)^;
end;

//获得实列大小
class function TObject.InstanceSize: Longint;
begin
Result := PInteger(Integer(Self) + vmtInstanceSize)^;
end;

//判断是否从一个类继承下来
class function TObject.InheritsFrom(AClass: TClass): Boolean;
{$IFDEF PUREPASCAL}
var
ClassPtr: TClass;
begin
ClassPtr := Self;
//当前类是否存在并且和比较的类不等
while (ClassPtr <> nil) and (ClassPtr <> AClass) do
//获得这个类的父类
ClassPtr := PPointer(Integer(ClassPtr) + vmtParent)^;
Result := ClassPtr = AClass;
end;
{$ELSE}
asm
{ -> EAX Pointer to our class }
{ EDX Pointer to AClass }
{ <- AL Boolean result }
JMP @@haveVMT
@@loop:
MOV EAX,[EAX]
@@haveVMT:
CMP EAX,EDX
JE @@success
MOV EAX,[EAX].vmtParent
TEST EAX,EAX
JNE @@loop
JMP @@exit
@@success:
MOV AL,1
@@exit:
end;

//根据方法名称获得地址
class function TObject.MethodAddress(const Name: ShortString): Pointer;
asm
{ -> EAX Pointer to class }
{ EDX Pointer to name }
PUSH EBX
PUSH ESI
PUSH EDI
XOR ECX,ECX //清零
XOR EDI,EDI //清零
MOV BL,[EDX] //获得字符串的长度
JMP @@haveVMT //判断是否有虚拟方发表
@@outer: { upper 16 bits of ECX are 0 ! }
MOV EAX,[EAX]
@@haveVMT:
MOV ESI,[EAX].vmtMethodTable //获得虚拟方发表的地址
TEST ESI,ESI //是否存在
JE @@parent //如果不存在
MOV DI,[ESI] { EDI := method count }方法的数量
ADD ESI,2 // 开始
@@inner: { upper 16 bits of ECX are 0 ! }
MOV CL,[ESI+6] { compare length of strings } //获得名城的长度
CMP CL,BL //比较长度
JE @@cmpChar //如果相等就开始比较字符
@@cont: { upper 16 bits of ECX are 0 ! }
MOV CX,[ESI] { fetch length of method desc } //获得方法的长度 //长度两个字节指针4个字节 ///
ADD ESI,ECX { point ESI to next method } //指向下一个函数
DEC EDI
JNZ @@inner
@@parent: //获得父的方发表
MOV EAX,[EAX].vmtParent { fetch parent vmt }
TEST EAX,EAX //是否为0
JNE @@outer //不为零
JMP @@exit { return NIL } //已经到根

@@notEqual:
MOV BL,[EDX] { restore BL to length of name } //存储名字的长度
JMP @@cont //转移

@@cmpChar: { upper 16 bits of ECX are 0 ! }
MOV CH,0 { upper 24 bits of ECX are 0 ! } ///清空高位字节
@@cmpCharLoop:
MOV BL,[ESI+ECX+6] { case insensitive string cmp } //获得第一个字符
XOR BL,[EDX+ECX+0] { last char is compared first } //比较
AND BL,$DF //清空其他标志位
JNE @@notEqual
DEC ECX { ECX serves as counter } //比较下一个
JNZ @@cmpCharLoop //如果不为零进行下一个字符的比较

{ found it }
MOV EAX,[ESI+2] //找到并且得到指针 12 方法长度 3456 方法指针 7890 方法名称 7 方法名城的长度

@@exit:
POP EDI
POP ESI
POP EBX
end;

//根据字段名获得地址
function TObject.FieldAddress(const Name: ShortString): Pointer;
asm
{ -> EAX Pointer to instance }
{ EDX Pointer to name }
PUSH EBX
PUSH ESI
PUSH EDI
XOR ECX,ECX //清空Cx
XOR EDI,EDI //清空Edit
MOV BL,[EDX] //获得Name的长度

PUSH EAX { save instance pointer } //保存当前实列指针

@@outer:
MOV EAX,[EAX] { fetch class pointer } //获得当前类的指针
MOV ESI,[EAX].vmtFieldTable //获得字段列表的地址
TEST ESI,ESI //是否存在
JE @@parent //如果不存在就到当前的父类查找
MOV DI,[ESI] { fetch count of fields } //获得字段的数量
ADD ESI,6 // 2 为数量 4 位指针
@@inner:
MOV CL,[ESI+6] { compare string lengths } //获得当前字段的长度
CMP CL,BL //比较长度
JE @@cmpChar //如果相等就开始比较字符
@@cont: ///LEA是取变量的地址
LEA ESI,[ESI+ECX+7] { point ESI to next field } //Esi指向下一个字段ESI 当前位子+ECX 长度+7 ？？？
DEC EDI //数量减一
JNZ @@inner //如果不等于零则继续比较
@@parent:
MOV EAX,[EAX].vmtParent { fetch parent VMT } //获得当前的父类地址
TEST EAX,EAX //是否存在
JNE @@outer //如果存在则准备获得字段数量
POP EDX { forget instance, return Nil } //否则恢复Edx 恢复实列返回nil 当前Eax为空
JMP @@exit //并且退出

@@notEqual:
MOV BL,[EDX] { restore BL to length of name } //获得目的字段名称的长度
MOV CL,[ESI+6] { ECX := length of field name } //获得源字段名城的长度
JMP @@cont

@@cmpChar:
MOV BL,[ESI+ECX+6] { case insensitive string cmp } //字符比较
XOR BL,[EDX+ECX+0] { starting with last char }
AND BL,$DF //标志位处理
JNE @@notEqual //如果不等
DEC ECX { ECX serves as counter } //字符长度减一
JNZ @@cmpChar //如果还有没有比较完的字符

{ found it }
MOV EAX,[ESI] { result is field offset plus ... } //获得当前的地址的偏移量
POP EDX //恢复当前实列到Edx
ADD EAX,EDX { instance pointer } //获得字段的偏移地址

@@exit:
POP EDI
POP ESI
POP EBX
end;

//

function TObject.GetInterface(const IID: TGUID; out Obj): Boolean;
var
InterfaceEntry: PInterfaceEntry;
begin
Pointer(Obj) := nil;
InterfaceEntry := GetInterfaceEntry(IID);
if InterfaceEntry <> nil then
begin
if InterfaceEntry^.IOffset <> 0 then
begin
Pointer(Obj) := Pointer(Integer(Self) + InterfaceEntry^.IOffset);
if Pointer(Obj) <> nil then IInterface(Obj)._AddRef;
end
else
IInterface(Obj) := InvokeImplGetter(Self, InterfaceEntry^.ImplGetter);
end;
Result := Pointer(Obj) <> nil;
end;

----------------------
一个实列的创建过程
s:=Tstrings.create ;
Mov Dl ,$01,
Mov Eax , [$00412564]; //？？
Call Tobject.create ;
{
Test dl,dl ;
Jz +$08 ///???
Add Esp,-$10;
Call @ClassCreate;
{
push Edx,
Push Ecx,
Push Ebx,
Test Dl,dl
jl +03
Call Dword Ptr[eax-$0c]
{
NewInStance
push Ebx
mov Ebx ,eax
mov Eax ,ebx
Call Tobject.instancesize
{
Add Eax,-$28
Mov Eax,[Eax]
Ret
}
Call @GetMem
{
push Ebx
Test Eax,Eax
jle +$15
Call Dword ptr [memoryManager]
Mov Ebx,Eax
Test Ebx,ebx
Jnz +$0B
mov Al,%01
Call Error
Xor Ebx,Ebx
pop Ebx
Ret
}
mov Edx,Eax
Mov Eax,Ebx,
call Tobject.initInstance
pop Ebx

}
Xor Edx,edx
Lea Ecx,[Esp+$10]
Mov Ebx,Fs:[Edx]
mov [Ecx],EDx
mov [Ecx+$08],ebx
mov [Ecx+$04],$0040340D
mov Fs:[Edx] , Ecx
pop Ebx
pop Ecx
pop Edx
}

}
Test dl,dl,
jz +0f
Call @AfterConStruction
pop Dword ptr Fs:[$00000000]
Add Esp ,$0c
}