分类： C/C++
2008-04-23 22:02:59
理解 COM 套间
; 汇编程序示例 data_seg segment ；定义数据段 n_i dw ? data_seg ends stack_seg segment ；定义堆栈 dw 128 dup(0) tos label word statck_seg ends code1 segment ；定义代码段 main proc far assume cs:ccode,ds;data,seg,ss:stack_seg start: move ax,stack_seg ；将定义的堆栈段的地址保存到ss mov ss,ax mov sp,offset tos ；将堆栈的最后地址保存到sp，堆栈是从下到上访问的 push ds ；保存旧的数据段 sub ax,ax push ax mov ax,data_seg ；将定义的数据段保存到ds mov ds,ax call fact ；调用子函数 ……. ；其它操作省略 ret ；返回到系统 main endp fact proc near ；子函数定义 …… ；具体操作省略 ret ；返回到调用处 fact endp code1 ends end start 示例1：汇编程序结构从以上程序我们看到，一个程序可以分为代码段，数据段，堆栈段等几部分。汇编编译器在编译的时候会将这些文件转化为成一个标准格式（在windows下被称为PE文件格式）的文件（很多时候可执行文件被命名为二进制文件，我不喜欢这个名字，我觉得它容易给人误解；事实上计算机上所有的文件都是0和1组成的，都是二进制文件；真正不同的就是处理这些文件的方式；EXE文件需要操作系统来调用，TXT文件需要写字本来打开；但其本质上并没有什么不同，只是在不同的组合上，二进制数有不同的意义）。该文件格式会把我们的代码按格式安放在不同的部分。程序必须在内存中，才可以执行。在程序运行前，操作系统会按照标准格式将这些内容加载到内存中。这些数据加载到内存中也需要按照一定的格式，CPU提供了DS,CS，SS等段寄存器，这样代码段的开始位置需要被CS指定，数据段的开始位置需要用DS来指定，SS需要指向堆栈的开始位置等。在DOS下，每次只能运行一个程序，这些内容基本构成了进程。但在Windows下，丰富了进程的内容，还包括一些数据结构用来维护我们程序中用到的图标，对话框等内容，以及线程。其实进程就是程序在内存中的组织形式，有了这样的组织形式，程序才可能运行。也就是说，当程序加载到内存中去后，就形成了一个进程。
…… mov eax，4 mov ebx，5 ……假如我们的程序运行到mov eax，4，那么EIP就会指向该句代码所在的内存的地址。当这行代码执行完毕之后，那么EIP会自动加一，那么它就会指向mov ebx，4。而程序的执行就是靠EIP的不断增加来完成的（跳转的话，EIP就变成了跳转到的地址）。在Windows系统下，进程并不拥有EIP，EAX，那么只有进程，一个程序就无法运行。而拥有这些寄存器的是线程，所以说进程是静态的。
//
// Context Frame
//
// This frame has a several purposes: 1) it is used as an argument to
// NtContinue, 2) is is used to constuct a call frame for APC delivery,
// and 3) it is used in the user level thread creation routines.
//
// The layout of the record conforms to a standard call frame.
//
typedef struct _CONTEXT {
//
// The flags values within this flag control the contents of
// a CONTEXT record.
//
// If the context record is used as an input parameter, then
// for each portion of the context record controlled by a flag
// whose value is set, it is assumed that that portion of the
// context record contains valid context. If the context record
// is being used to modify a threads context, then only that
// portion of the threads context will be modified.
//
// If the context record is used as an IN OUT parameter to capture
// the context of a thread, then only those portions of the thread''s
// context corresponding to set flags will be returned.
//
// The context record is never used as an OUT only parameter.
//
DWORD ContextFlags;
//
// This section is specified/returned if CONTEXT_DEBUG_REGISTERS is
// set in ContextFlags. Note that CONTEXT_DEBUG_REGISTERS is NOT
// included in CONTEXT_FULL.
//
DWORD Dr0;
DWORD Dr1;
DWORD Dr2;
DWORD Dr3;
DWORD Dr6;
DWORD Dr7;
//
// This section is specified/returned if the
// ContextFlags word contians the flag CONTEXT_FLOATING_POINT.
//
FLOATING_SAVE_AREA FloatSave;
//
// This section is specified/returned if the
// ContextFlags word contians the flag CONTEXT_SEGMENTS.
//
DWORD SegGs;
DWORD SegFs;
DWORD SegEs;
DWORD SegDs;
//
// This section is specified/returned if the
// ContextFlags word contians the flag CONTEXT_INTEGER.
//
DWORD Edi;
DWORD Esi;
DWORD Ebx;
DWORD Edx;
DWORD Ecx;
DWORD Eax;
//
// This section is specified/returned if the
// ContextFlags word contians the flag CONTEXT_CONTROL.
//
DWORD Ebp;
DWORD Eip;
DWORD SegCs; // MUST BE SANITIZED
DWORD EFlags; // MUST BE SANITIZED
DWORD Esp;
DWORD SegSs;
//
// This section is specified/returned if the ContextFlags word
// contains the flag CONTEXT_EXTENDED_REGISTERS.
// The format and contexts are processor specific
//
BYTE ExtendedRegisters[MAXIMUM_SUPPORTED_EXTENSION];
} CONTEXT;
好了，线程就先讲这么多了。如果对进程和线程的内容感兴趣，可以到Intel的网站下载PDF格式的电子书《IA-32 Intel Architecture Software Developer’s Manual》，纸版的书也可以在这儿预定（他们会免费邮寄给你）。通过这套书，你可以对CPU的结构有一个清晰的认识。另外可以找几本讲解Windows系统的书看看，不过这类的好书不多，最著名的是《Advance Windows》，不过也是偏向于实用，对系统结构的讲解不多。也是，要完全去了解这部分的细节，太困难了，毕竟微软没有给我们提供这部分的源码。幸好，其实我们理解它大致的原理就足够用了。
#include这段程序的本意是让全局变量累次加10，并打印出操作后的数值。但我们运行程序后的结果如下，可以看到程序的运行结果非我们所愿。打印出的结果是一串乱序的文字。#include int g_i = 10; //一个全局变量 DWORD WINAPI ThreadProc(LPVOID lpv) { g_i = 10; std::cout <<"In the Thread " << ::GetCurrentThreadId() << ",the first g_i is " << g_i << "!" << std::endl; Sleep(5000); //睡眠 g_i = 10; std::cout <<"In the Thread " << ::GetCurrentThreadId() << ",the secend g_i is " << g_i << "!" << std::endl; return 0; } int main(int argc, char* argv[]) { DWORD threadID[2]; HANDLE hThreads[2]; for(int i = 0; i <= 1; i ) //创建两个线程 hThreads[i] = ::CreateThread(NULL, 0, ThreadProc, NULL, 0, &threadID[i]); WaitForMultipleObjects(2,hThreads,TRUE,INFINITE); //等待线程结束 for(i = 0; i <= 1; i ) ::CloseHandle(hThreads[i]); //关闭线程句柄 system("pause"); return 0; } 示例程序2-多线程程序
#include再次运行，结果就是我们所需要的了。#include int g_i = 10; //一个全局变量 CRITICAL_SECTION cs; //一个临界区变量 DWORD WINAPI ThreadProc(LPVOID lpv) { EnterCriticalSection(&cs); //进入临界区 g_i = 10; std::cout <<"In the Thread " << ::GetCurrentThreadId() << ",the first g_i is " << g_i << "!" << std::endl; ::LeaveCriticalSection(&cs); Sleep(5000); //睡眠 EnterCriticalSection(&cs); g_i = 10; std::cout <<"In the Thread " << ::GetCurrentThreadId() << ",the secend g_i is " << g_i << "!" << std::endl; ::LeaveCriticalSection(&cs); return 0; } int main(int argc, char* argv[]) { DWORD threadID[2]; HANDLE hThreads[2]; InitializeCriticalSection(&cs); for(int i = 0; i <= 1; i ) //创建两个线程 hThreads[i] = ::CreateThread(NULL, 0, ThreadProc, NULL, 0, &threadID[i]); WaitForMultipleObjects(2,hThreads,TRUE,INFINITE); //等待线程结束 for(i = 0; i <= 1; i ) ::CloseHandle(hThreads[i]); //关闭线程句柄 system("pause"); return 0; }
#define _WIN32_WINNT 0x0400 #include该段程序将main中定义的ITestInterface1对象，通过指针传到了新建的线程中。运行该段程序，结果如下，又是一串乱序的文字串。也就是说我们需要在TestComObject1中对TestFunc1进行线程同步控制。但大多数人并不想这样做，因为我们开发的组件大多数情况下并不会在多线程执行。但为了避免低概率事件发生后的不良后果，套间出场了。#include #include "..\TestComObject1\TestComObject1_i.c" #include "..\TestComObject1\TestComObject1.h" DWORD WINAPI ThreadProc(LPVOID lpv) { HRESULT hr = CoInitializeEx(NULL, COINIT_APARTMENTTHREADED); if ( FAILED(hr) ) { std::cout << "CoinitializeEx failed!" << std::endl; return 0; } ITestInterface1 *pTest = NULL; hr = ::CoCreateInstance(CLSID_TestInterface1, 0, CLSCTX_INPROC, IID_ITestInterface1, (void**)&pTest); if ( FAILED(hr) ) { std::cout << "CoCreateInstance failed!" << std::endl; return 0; } hr = pTest->TestFunc1(); if ( FAILED(hr) ) { std::cout << "TestFunc1 failed!" << std::endl; return 0; } pTest->Release(); ::CoUninitialize(); return 0; } int main(int argc, char* argv[]) { HRESULT hr = CoInitializeEx(NULL, COINIT_APARTMENTTHREADED); if ( FAILED(hr) ) { std::cout << "CoinitializeEx failed!" << std::endl; return 0; } ITestInterface1 *pTest = NULL; hr = ::CoCreateInstance(CLSID_TestInterface1, 0, CLSCTX_INPROC, IID_ITestInterface1, (void**)&pTest); if ( FAILED(hr) ) { std::cout << "CoCreateInstance failed!" << std::endl; return 0; } DWORD threadID; HANDLE hThreads = ::CreateThread(NULL, //创建一个进程 0, ThreadProc, NULL, //将pTest作为一个参数传入新线程 0, &threadID); hr = pTest->TestFunc1(); if ( FAILED(hr) ) { std::cout << "TestFunc1 failed!" << std::endl; return 0; } ::WaitForSingleObject(hThreads,INFINITE); //等待线程结束 ::CloseHandle(hThreads); //关闭线程句柄 pTest->Release(); ::CoUninitialize(); system("pause"); return 0; }
STDMETHODIMP CTestInterface1::TestFunc1()
{
// TODO: Add your implementation code here
std::cout << "In the itestinferface1''s object, the thread''s id is " << ::GetCurrentThreadId() << std::endl;
return S_OK;
}
该方法非常简单，就是打印出该方法运行时，所在的线程的ID号。如果在不同的线程中调用同一个对象的时候，通过套间，发送消息，最终该对象只应该在一个线程中运行，所以它的线程ID号应该是相同的。我们将通过该ID值来验证套间的存在。
#define _WIN32_WINNT 0x0400 #include#include #include "..\TestComObject1\TestComObject1_i.c" #include "..\TestComObject1\TestComObject1.h" DWORD WINAPI ThreadProc(LPVOID lpv) { HRESULT hr = CoInitializeEx(NULL, COINIT_APARTMENTTHREADED); if ( FAILED(hr) ) { std::cout << "CoinitializeEx failed!" << std::endl; return 0; } ITestInterface1 *pTest = NULL; hr = ::CoCreateInstance(CLSID_TestInterface1, 0, CLSCTX_INPROC, IID_ITestInterface1, (void**)&pTest); if ( FAILED(hr) ) { std::cout << "CoCreateInstance failed!" << std::endl; return 0; } hr = pTest->TestFunc1(); if ( FAILED(hr) ) { std::cout << "TestFunc1 failed!" << std::endl; return 0; } pTest->Release(); ::CoUninitialize(); return 0; } int main(int argc, char* argv[]) { HRESULT hr = CoInitializeEx(NULL, COINIT_APARTMENTTHREADED); if ( FAILED(hr) ) { std::cout << "CoinitializeEx failed!" << std::endl; return 0; } ITestInterface1 *pTest = NULL; hr = ::CoCreateInstance(CLSID_TestInterface1, 0, CLSCTX_INPROC, IID_ITestInterface1, (void**)&pTest); if ( FAILED(hr) ) { std::cout << "CoCreateInstance failed!" << std::endl; return 0; } hr = pTest->TestFunc1(); if ( FAILED(hr) ) { std::cout << "TestFunc1 failed!" << std::endl; return 0; } DWORD threadID; HANDLE hThreads[1]; hThreads[0] = ::CreateThread(NULL, //创建一个进程 0, ThreadProc, (LPVOID)pTest, //将pTest作为一个参数传入新线程 0, &threadID); ::WaitForSingleObject(hThreads,INFINITE); //等待线程结束 ::CloseHandle(hThreads); //关闭线程句柄 pTest->Release(); ::CoUninitialize(); system("pause"); return 0; }
DWORD ApartMentMsgWaitForMultipleObject(HANDLE *hHandle,DWORD dwWaitCout, DWORD dwMilliseconds)
{
BOOL bQuit = FALSE;
DWORD dwRet;
while(!bQuit)
{
int rc;
rc = ::MsgWaitForMultipleObjects
(
dwWaitCout, // 需要等待的对象数量
hHandle, // 对象树组
FALSE, //等待所有的对象
(DWORD)dwMilliseconds, // 等待的时间
(DWORD)(QS_ALLINPUT | QS_ALLPOSTMESSAGE) // 事件类型
);
//等待的事件激发
if( rc == WAIT_OBJECT_0 )
{
dwRet = rc;
bQuit = TRUE;
}
//其他windows消息
else if( rc == WAIT_OBJECT_0 dwWaitCout )
{
MSG msg;
while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
{
TranslateMessage (&msg);
DispatchMessage(&msg);
}
}
}
return dwRet;
}
该函数用来处理消息的同步，也够麻烦的，还需要自己写这段程序。这段程序的意思是如果等待的事件被激发，那么设置bQuit为TURE，那么退出消息循环。如果接收到其它的消息的话，再分发出去。好了，把我们的程序再改一下：
// ::WaitForSingleObject(hThreads,INFINITE); //等待线程结束 ApartMentMsgWaitForMultipleObject(hThreads,1,INFINITE);
#define _WIN32_WINNT 0x0400 #include我们通过CoGetInterfaceAndReleaseStream将main中的pTest变为pStream，然后将pStream作为参数传入到线程中，然后再通过CoGetInterfaceAndReleaseStream将pSteam变为接口指针。再来看看运行的结果：#include #include "..\TestComObject1\TestComObject1_i.c" #include "..\TestComObject1\TestComObject1.h" DWORD WINAPI ThreadProc(LPVOID lpv) { //HRESULT hr = CoInitializeEx(NULL, COINIT_APARTMENTTHREADED); HRESULT hr = CoInitializeEx(NULL, COINIT_MULTITHREADED); if ( FAILED(hr) ) { std::cout << "CoinitializeEx failed!" << std::endl; return 0; } IStream *pStream = (IStream*)lpv; ITestInterface1 *pTest = NULL; hr = ::CoGetInterfaceAndReleaseStream(pStream, IID_ITestInterface1, (void**)&pTest); if ( FAILED(hr) ) { std::cout << "CoGetInterfaceAndReleaseStream failed!" << std::endl; return 0; } hr = pTest->TestFunc1(); if ( FAILED(hr) ) { std::cout << "TestFunc1 failed!" << std::endl; return 0; } pTest->Release(); ::CoUninitialize(); return 0; } DWORD ApartMentMsgWaitForMultipleObject(HANDLE *hHandle,DWORD dwWaitCout, DWORD dwMilliseconds) { BOOL bQuit = FALSE; DWORD dwRet; while(!bQuit) { int rc; rc = ::MsgWaitForMultipleObjects ( dwWaitCout, // 需要等待的对象数量 hHandle, // 对象树组 FALSE, //等待所有的对象 (DWORD)dwMilliseconds, // 等待的时间 (DWORD)(QS_ALLINPUT | QS_ALLPOSTMESSAGE) // 事件类型 ); if( rc == WAIT_OBJECT_0 ) { dwRet = rc; bQuit = TRUE; } else if( rc == WAIT_OBJECT_0 dwWaitCout ) { MSG msg; while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) { TranslateMessage (&msg); DispatchMessage(&msg); } } } return dwRet; } int main(int argc, char* argv[]) { //HRESULT hr = CoInitializeEx(NULL, COINIT_APARTMENTTHREADED); HRESULT hr = CoInitializeEx(NULL, COINIT_MULTITHREADED); if ( FAILED(hr) ) { std::cout << "CoinitializeEx failed!" << std::endl; return 0; } ITestInterface1 *pTest = NULL; hr = ::CoCreateInstance(CLSID_TestInterface1, 0, CLSCTX_INPROC, IID_ITestInterface1, (void**)&pTest); if ( FAILED(hr) ) { std::cout << "CoCreateInstance failed!" << std::endl; return 0; } hr = pTest->TestFunc1(); if ( FAILED(hr) ) { std::cout << "TestFunc1 failed!" << std::endl; return 0; } IStream *pStream = NULL; hr = ::CoMarshalInterThreadInterfaceInStream(IID_ITestInterface1, pTest, &pStream); if ( FAILED(hr) ) { std::cout << "CoMarshalInterThreadInterfaceInStream failed!" << std::endl; return 0; } DWORD threadID; HANDLE hThreads[1]; hThreads[0] = ::CreateThread(NULL, //创建一个进程 0, ThreadProc, (LPVOID)pStream, //将pStream作为一个参数传入新线程 0, &threadID); ApartMentMsgWaitForMultipleObject(hThreads,1,INFINITE); ::CloseHandle(hThreads); //关闭线程句柄 pTest->Release(); ::CoUninitialize(); system("pause"); return 0; }
#define _WIN32_WINNT 0x0400 #include此部分代码与我们测试Apartment时的代码基本相同，只是新增了输出main和创建线程的ID的语句。好的，我们来运行程序，可以得到如下的结果：#include #include "..\TestComObject1\TestComObject1_i.c" #include "..\TestComObject1\TestComObject1.h" DWORD WINAPI ThreadProc(LPVOID lpv) { HRESULT hr = CoInitializeEx(NULL, COINIT_APARTMENTTHREADED); //HRESULT hr = CoInitializeEx(NULL, COINIT_MULTITHREADED); if ( FAILED(hr) ) { std::cout << "CoinitializeEx failed!" << std::endl; return 0; } IStream *pStream = (IStream*)lpv; ITestInterface1 *pTest = NULL; hr = ::CoGetInterfaceAndReleaseStream(pStream, IID_ITestInterface1, (void**)&pTest); if ( FAILED(hr) ) { std::cout << "CoGetInterfaceAndReleaseStream failed!" << std::endl; return 0; } std::cout << "ThradProc''s threadid is " << ::GetCurrentThreadId() << std::endl; //输出ThradProc的线程ID hr = pTest->TestFunc1(); if ( FAILED(hr) ) { std::cout << "TestFunc1 failed!" << std::endl; return 0; } pTest->Release(); ::CoUninitialize(); return 0; } DWORD ApartMentMsgWaitForMultipleObject(HANDLE *hHandle,DWORD dwWaitCout, DWORD dwMilliseconds) { BOOL bQuit = FALSE; DWORD dwRet; while(!bQuit) { int rc; rc = ::MsgWaitForMultipleObjects ( dwWaitCout, // 需要等待的对象数量 hHandle, // 对象树组 FALSE, //等待所有的对象 (DWORD)dwMilliseconds, // 等待的时间 (DWORD)(QS_ALLINPUT | QS_ALLPOSTMESSAGE) // 事件类型 ); if( rc == WAIT_OBJECT_0 ) { dwRet = rc; bQuit = TRUE; } else if( rc == WAIT_OBJECT_0 dwWaitCout ) { MSG msg; while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) { TranslateMessage (&msg); DispatchMessage(&msg); } } } return dwRet; } int main(int argc, char* argv[]) { HRESULT hr = CoInitializeEx(NULL, COINIT_APARTMENTTHREADED); //HRESULT hr = CoInitializeEx(NULL, COINIT_MULTITHREADED); if ( FAILED(hr) ) { std::cout << "CoinitializeEx failed!" << std::endl; return 0; } ITestInterface1 *pTest = NULL; hr = ::CoCreateInstance(CLSID_TestInterface1, 0, CLSCTX_INPROC, IID_ITestInterface1, (void**)&pTest); if ( FAILED(hr) ) { std::cout << "CoCreateInstance failed!" << std::endl; return 0; } std::cout << "main''s threadid is " << ::GetCurrentThreadId() << std::endl; //打印main的线程ID hr = pTest->TestFunc1(); if ( FAILED(hr) ) { std::cout << "TestFunc1 failed!" << std::endl; return 0; } IStream *pStream = NULL; hr = ::CoMarshalInterThreadInterfaceInStream(IID_ITestInterface1, pTest, &pStream); if ( FAILED(hr) ) { std::cout << "CoMarshalInterThreadInterfaceInStream failed!" << std::endl; return 0; } DWORD threadID; HANDLE hThreads[1]; hThreads[0] = ::CreateThread(NULL, //创建一个进程 0, ThreadProc, (LPVOID)pStream, //将pStream作为一个参数传入新线程 0, &threadID); ApartMentMsgWaitForMultipleObject(hThreads,1,INFINITE); ::CloseHandle(hThreads); //关闭线程句柄 pTest->Release(); ::CoUninitialize(); system("pause"); return 0; }
