昨天写《用程序来模拟文件拖放》的时候，程序刚刚运行通过，测试用例是向 WordPad 也即写字板里面扔一个文件。今天把程序改了改，向真实案例继续靠近，往 360 加固助手里扔 apk 包，不出意外地失败了。我就说嘛，老天爷怎么会如此轻易放过老夫。
不过这个情况并不棘手。因为截至目前，已经证明拖放的支持基础是很坚实的。为什么 360 加固助手不能像预期那样正确接收投喂，几乎可以百分百确定是格式枚举部分的支持没有完成而导致的。还好有前人在这块儿做出过泽惠吾等的努力，实现过一个开箱即用的格式枚举辅助类，略作修改后投入使用，再测试，就一马平川了。
涉及到对上一篇文章中代码的改动有两处，一是加上 #include "enumfmt.h"，二是对 EnumFormatEtc 方法进行填充，在原有的一条返回语句前增加以下三行：
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FORMATETC fmt = { CF_HDROP, NULL, DVASPECT_CONTENT, -1, TYMED_HGLOBAL }; if(dwDirection == DATADIR_GET) return CEnumFormatEtc::Create(1, &fmt, ppEnumFormatEtc); |
此处附上 enumfmt.h 头文件的内容如下：
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#include <windows.h> class CEnumFormatEtc : public IEnumFORMATETC { static HRESULT CreateEnumFormatEtc(UINT nNumFormats, FORMATETC *pFormatEtc, IEnumFORMATETC **ppEnumFormatEtc) { if(nNumFormats == 0 || pFormatEtc == 0 || ppEnumFormatEtc == 0) return E_INVALIDARG; *ppEnumFormatEtc = new CEnumFormatEtc(pFormatEtc, nNumFormats); return (*ppEnumFormatEtc) ? S_OK : E_OUTOFMEMORY; } // Helper function to perform a "deep" copy of a FORMATETC static void DeepCopyFormatEtc(FORMATETC *dest, FORMATETC *source) { // copy the source FORMATETC into dest *dest = *source; if(source->ptd) { // allocate memory for the DVTARGETDEVICE if necessary dest->ptd = (DVTARGETDEVICE*)CoTaskMemAlloc(sizeof(DVTARGETDEVICE)); // copy the contents of the source DVTARGETDEVICE into dest->ptd *(dest->ptd) = *(source->ptd); } } public: // "Drop-in" replacement for SHCreateStdEnumFmtEtc. Called by CDataObject::EnumFormatEtc static HRESULT Create(UINT nNumFormats, FORMATETC *pFormatEtc, IEnumFORMATETC **ppEnumFormatEtc) { return CreateEnumFormatEtc(nNumFormats, pFormatEtc, ppEnumFormatEtc); } public: // // IUnknown members // HRESULT __stdcall QueryInterface (REFIID iid, void ** ppvObject) { // check to see what interface has been requested if(iid == IID_IEnumFORMATETC || iid == IID_IUnknown) { AddRef(); *ppvObject = this; return S_OK; } *ppvObject = 0; return E_NOINTERFACE; } ULONG __stdcall AddRef (void) { // increment object reference count return InterlockedIncrement(&m_lRefCount); } ULONG __stdcall Release (void) { // decrement object reference count LONG count = InterlockedDecrement(&m_lRefCount); if(count == 0) { delete this; return 0; } return count; } // // IEnumFormatEtc members // // If the returned FORMATETC structure contains a non-null "ptd" member, then // the caller must free this using CoTaskMemFree (stated in the COM documentation) // HRESULT __stdcall Next (ULONG celt, FORMATETC * rgelt, ULONG * pceltFetched) { // validate arguments if(celt == 0 || rgelt == 0) return E_INVALIDARG; // copy FORMATETC structures into caller's buffer ULONG copied = 0; while(m_nIndex < m_nNumFormats && copied < celt) { DeepCopyFormatEtc(&rgelt[copied], &m_pFormatEtc[m_nIndex]); copied++; m_nIndex++; } // store result if(pceltFetched != 0) *pceltFetched = copied; // did we copy all that was requested? return (copied == celt) ? S_OK : S_FALSE; } HRESULT __stdcall Skip (ULONG celt) { m_nIndex += celt; return (m_nIndex <= m_nNumFormats) ? S_OK : S_FALSE; } HRESULT __stdcall Reset (void) { m_nIndex = 0; return S_OK; } HRESULT __stdcall Clone (IEnumFORMATETC ** ppEnumFormatEtc) { // make a duplicate enumerator HRESULT hResult = CreateEnumFormatEtc(m_nNumFormats, m_pFormatEtc, ppEnumFormatEtc); if(hResult == S_OK) { // manually set the index state ((CEnumFormatEtc *) *ppEnumFormatEtc)->m_nIndex = m_nIndex; } return hResult; } // // Construction / Destruction // CEnumFormatEtc(FORMATETC *pFormatEtc, int nNumFormats) { m_lRefCount = 1; m_nIndex = 0; m_nNumFormats = nNumFormats; m_pFormatEtc = new FORMATETC[nNumFormats]; // copy the FORMATETC structures for(int i = 0; i < nNumFormats; i++) { DeepCopyFormatEtc(&m_pFormatEtc[i], &pFormatEtc[i]); } } ~CEnumFormatEtc() { if(m_pFormatEtc) { for(ULONG i = 0; i < m_nNumFormats; i++) { if(m_pFormatEtc[i].ptd) CoTaskMemFree(m_pFormatEtc[i].ptd); } delete[] m_pFormatEtc; } } private: LONG m_lRefCount; // Reference count for this COM interface ULONG m_nIndex; // current enumerator index ULONG m_nNumFormats; // number of FORMATETC members FORMATETC * m_pFormatEtc; // array of FORMATETC objects }; |