IMAPI2:添加文件和文件夹失败

Question

我正试图通过IMAPI2创建一个光盘映像。代码非常简单：

#include <windows.h>
#include <iostream>
#include <fstream>
#include <shlwapi.h>
#include <cstdio>

#include <imapi.h>
#include <imapi2.h>
#include <imapi2fs.h>
#include <imapierror.h>
#include <imapi2error.h>
#include <imapi2fserror.h>

using namespace std;

int main() {
CoInitialize(NULL);

HRESULT res = 0;
IFileSystemImage* image = NULL;
IFileSystemImageResult* result = NULL;
IFsiDirectoryItem* root = NULL;
IStream* file = NULL;
IStream* r_i = NULL;

res = CoCreateInstance(CLSID_MsftFileSystemImage, NULL, CLSCTX_ALL, __uuidof(IFileSystemImage), (void**) &image);
printf("1 %08X\n", res);
res = image -> put_FileSystemsToCreate((FsiFileSystems)(FsiFileSystemJoliet | FsiFileSystemISO9660));
printf("2 %08X\n", res);
res = image -> put_VolumeName(L"Pictures");
printf("3 %08X\n", res);
res = image -> ChooseImageDefaultsForMediaType(IMAPI_MEDIA_TYPE_CDRW);
printf("4 %08X\n", res);

res = image -> get_Root(&root);
printf("5 %08X\n", res);
res = root -> AddTree(L"C:\\pictures", VARIANT_TRUE);
printf("6 %08X\n", res);
res = SHCreateStreamOnFileEx(L"C:\\main.cpp", STGM_READ | STGM_SHARE_DENY_NONE | STGM_DELETEONRELEASE, FILE_ATTRIBUTE_NORMAL, false, NULL, &file);
printf("7 %08X\n", res);
res = root -> AddFile(L"main.cpp", file);
printf("8 %08X\n", res);

res = image -> CreateResultImage(&result);
printf("9 %08X\n", res);
res = result -> get_ImageStream(&r_i);
printf("0 %08X\n", res);

STATSTG stg;
r_i -> Stat(&stg, 1);
char* data = new char[stg.cbSize.QuadPart];
ULONG junk;
r_i -> Read(data, stg.cbSize.QuadPart, &junk);

FILE* f = fopen("image.iso", "wb");
fwrite(data, stg.cbSize.QuadPart, 1, f);
fclose(f);

delete data;
r_i -> Release();
file -> Release();
root -> Release();
result -> Release();
image -> Release();

CoUninitialize();
printf("Completed.\n");
scanf("%d", &junk);
}

命令6和8对0xC0AAB101 (无效参数)失败。这发生在Win XP SP3和Win 7 Pro SP1 x32上。其余的工作正常，我得到了一个空的图像。我遗漏了什么？(P.S.上面的代码是受一款开源应用的启发。(它开箱即用，但有时当我在我的机器上重建它时，它就会开始失效。)

Answer 1

->AddTree (和大多数COM对象方法)期望一个BSTR字符串，您可以创建该字符串，并需要释放它以防止内存泄漏。你可以用一些东西比如..。

// allocate a bstr string
BSTR bstrPictures = SysAllocString(L"C:\\Pictures");

// use it
res = root -> AddTree(bstrPictures, VARIANT_TRUE);
printf("6 %08X\n", res);

// free the bstr string
SysFreeString(bstrPictures);

虽然BSTR可以代替“宽字符字符串”，但相反的情况并不总是正确的。BSTR在实际字符数据前面有额外的数据，因此需要对它们进行操作。

尽量不要养成这样使用它们的坏习惯.

res = root -> AddTree(SysAllocString(L"C:\\Pictures"), VARIANT_TRUE);

因为你会有一个内存泄漏。

玩得开心。