sousa-gecko/widget/windows/nsDataObjCollection.cpp

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include <shlobj.h>

#include "mozilla/CheckedInt.h"
#include "mozilla/ScopeExit.h"
#include "nsDataObjCollection.h"
#include "nsClipboard.h"
#include "IEnumFE.h"

#include <ole2.h>

// {25589C3E-1FAC-47b9-BF43-CAEA89B79533}
const IID IID_IDataObjCollection = {
    0x25589c3e,
    0x1fac,
    0x47b9,
    {0xbf, 0x43, 0xca, 0xea, 0x89, 0xb7, 0x95, 0x33}};

/*
 * Class nsDataObjCollection
 */

nsDataObjCollection::nsDataObjCollection() {}

nsDataObjCollection::~nsDataObjCollection() { mDataObjects.Clear(); }

// IUnknown interface methods - see iunknown.h for documentation
STDMETHODIMP nsDataObjCollection::QueryInterface(REFIID riid, void** ppv) {
  *ppv = nullptr;

  if ((IID_IUnknown == riid) || (IID_IDataObject == riid)) {
    *ppv = static_cast<IDataObject*>(this);
    AddRef();
    return NOERROR;
  }

  if (IID_IDataObjCollection == riid) {
    *ppv = static_cast<nsIDataObjCollection*>(this);
    AddRef();
    return NOERROR;
  }
  // offer to operate asynchronously (required by nsDragService)
  if (IID_IDataObjectAsyncCapability == riid) {
    *ppv = static_cast<IDataObjectAsyncCapability*>(this);
    AddRef();
    return NOERROR;
  }

  return E_NOINTERFACE;
}

STDMETHODIMP_(ULONG) nsDataObjCollection::AddRef() { return ++m_cRef; }

STDMETHODIMP_(ULONG) nsDataObjCollection::Release() {
  if (0 != --m_cRef) return m_cRef;

  delete this;

  return 0;
}

// IDataObject methods
STDMETHODIMP nsDataObjCollection::GetData(LPFORMATETC pFE, LPSTGMEDIUM pSTM) {
  static CLIPFORMAT fileDescriptorFlavorA =
      ::RegisterClipboardFormat(CFSTR_FILEDESCRIPTORA);
  static CLIPFORMAT fileDescriptorFlavorW =
      ::RegisterClipboardFormat(CFSTR_FILEDESCRIPTORW);
  static CLIPFORMAT fileFlavor = ::RegisterClipboardFormat(CFSTR_FILECONTENTS);

  switch (pFE->cfFormat) {
    case CF_TEXT:
      return GetText<char, nsAutoCString>(pFE, pSTM);
    case CF_UNICODETEXT:
      return GetText<char16_t, nsAutoString>(pFE, pSTM);
    case CF_HDROP:
      return GetFile(pFE, pSTM);
    default:
      if (pFE->cfFormat == fileDescriptorFlavorA ||
          pFE->cfFormat == fileDescriptorFlavorW) {
        return GetFileDescriptors(pFE, pSTM,
                                  pFE->cfFormat == fileDescriptorFlavorW);
      }
      if (pFE->cfFormat == fileFlavor) {
        return GetFileContents(pFE, pSTM);
      }
  }
  return GetFirstSupporting(pFE, pSTM);
}

STDMETHODIMP nsDataObjCollection::GetDataHere(LPFORMATETC pFE,
                                              LPSTGMEDIUM pSTM) {
  return E_FAIL;
}

// Other objects querying to see if we support a particular format
STDMETHODIMP nsDataObjCollection::QueryGetData(LPFORMATETC pFE) {
  UINT format = nsClipboard::GetFormat(MULTI_MIME);

  if (format == pFE->cfFormat) {
    return S_OK;
  }

  for (uint32_t i = 0; i < mDataObjects.Length(); ++i) {
    IDataObject* dataObj = mDataObjects.ElementAt(i);
    if (S_OK == dataObj->QueryGetData(pFE)) {
      return S_OK;
    }
  }

  return DV_E_FORMATETC;
}

STDMETHODIMP nsDataObjCollection::SetData(LPFORMATETC pFE, LPSTGMEDIUM pSTM,
                                          BOOL fRelease) {
  // Set arbitrary data formats on the first object in the collection and let
  // it handle the heavy lifting
  if (mDataObjects.Length() == 0) return E_FAIL;
  return mDataObjects.ElementAt(0)->SetData(pFE, pSTM, fRelease);
}

// Registers a DataFlavor/FE pair
void nsDataObjCollection::AddDataFlavor(const char* aDataFlavor,
                                        LPFORMATETC aFE) {
  // Add the FormatEtc to our list if it's not already there.  We don't care
  // about the internal aDataFlavor because nsDataObj handles that.
  IEnumFORMATETC* ifEtc;
  FORMATETC fEtc;
  ULONG num;
  if (S_OK != this->EnumFormatEtc(DATADIR_GET, &ifEtc)) return;
  while (S_OK == ifEtc->Next(1, &fEtc, &num)) {
    NS_ASSERTION(
        1 == num,
        "Bit off more than we can chew in nsDataObjCollection::AddDataFlavor");
    if (FormatsMatch(fEtc, *aFE)) {
      ifEtc->Release();
      return;
    }
  }  // If we didn't find a matching format, add this one
  ifEtc->Release();
  m_enumFE->AddFormatEtc(aFE);
}

// We accept ownership of the nsDataObj which we free on destruction
void nsDataObjCollection::AddDataObject(IDataObject* aDataObj) {
  nsDataObj* dataObj = reinterpret_cast<nsDataObj*>(aDataObj);
  mDataObjects.AppendElement(dataObj);
}

// Methods for getting data
HRESULT nsDataObjCollection::GetFile(LPFORMATETC pFE, LPSTGMEDIUM pSTM) {
  STGMEDIUM workingmedium;
  FORMATETC fe = *pFE;
  HGLOBAL hGlobalMemory;
  HRESULT hr;
  // Make enough space for the header and the trailing null
  size_t buffersize = sizeof(DROPFILES) + sizeof(char16_t);
  char16_t* realbuffer;
  nsAutoString filename;

  hGlobalMemory = GlobalAlloc(GHND, buffersize);
  auto freeOnError =
      mozilla::MakeScopeExit([&]() { GlobalFree(hGlobalMemory); });

  for (uint32_t i = 0; i < mDataObjects.Length(); ++i) {
    nsDataObj* dataObj = mDataObjects.ElementAt(i);
    hr = dataObj->GetData(&fe, &workingmedium);
    if (hr != S_OK) {
      switch (hr) {
        case DV_E_FORMATETC:
          continue;
        default:
          return hr;
      }
    }
    // Now we need to pull out the filename
    char16_t* buffer = (char16_t*)GlobalLock(workingmedium.hGlobal);
    if (buffer == nullptr) {
      return E_FAIL;
    }
    buffer += sizeof(DROPFILES) / sizeof(char16_t);
    filename = buffer;
    GlobalUnlock(workingmedium.hGlobal);
    ReleaseStgMedium(&workingmedium);
    // Now put the filename into our buffer
    mozilla::CheckedInt<size_t> alloclen =
        mozilla::CheckedInt<size_t>(filename.Length() + 1) * sizeof(char16_t);
    mozilla::CheckedInt<size_t> totalsize = alloclen + buffersize;
    if (!totalsize.isValid()) {
      return E_FAIL;
    }
    MOZ_ASSERT(alloclen.isValid());
    HGLOBAL reallocedGlobalMemory =
        ::GlobalReAlloc(hGlobalMemory, totalsize.value(), GHND);
    if (reallocedGlobalMemory == nullptr) {
      // hGlobalMemory is still allocated but will be freed here.
      return E_FAIL;
    }
    hGlobalMemory = reallocedGlobalMemory;
    auto* tmemory = (char*)::GlobalLock(hGlobalMemory);
    if (!tmemory) {
      return E_FAIL;
    }
    realbuffer = reinterpret_cast<char16_t*>(tmemory + buffersize);
    realbuffer--;  // Overwrite the preceding null
    memcpy(realbuffer, filename.get(), alloclen.value());
    GlobalUnlock(hGlobalMemory);
    buffersize = totalsize.value();
  }
  // We get the last null (on the double null terminator) for free since we used
  // the zero memory flag when we allocated.  All we need to do is fill the
  // DROPFILES structure
  DROPFILES* df = (DROPFILES*)GlobalLock(hGlobalMemory);
  if (!df) {
    return E_FAIL;
  }
  df->pFiles = sizeof(DROPFILES);  // Offset to start of file name string
  df->fNC = 0;
  df->pt.x = 0;
  df->pt.y = 0;
  df->fWide = TRUE;  // utf-16 chars
  GlobalUnlock(hGlobalMemory);
  // Finally fill out the STGMEDIUM struct
  pSTM->tymed = TYMED_HGLOBAL;
  pSTM->pUnkForRelease = nullptr;  // Caller gets to free the data
  pSTM->hGlobal = hGlobalMemory;

  freeOnError.release();
  return S_OK;
}

template <typename CharT, typename StringT>
HRESULT nsDataObjCollection::GetText(LPFORMATETC pFE, LPSTGMEDIUM pSTM) {
  STGMEDIUM workingmedium;
  FORMATETC fe = *pFE;
  HGLOBAL hGlobalMemory;
  HRESULT hr;
  size_t buffersize = sizeof(CharT);

  hGlobalMemory = GlobalAlloc(GHND, buffersize);
  auto freeOnError =
      mozilla::MakeScopeExit([&]() { GlobalFree(hGlobalMemory); });

  StringT text;
  for (uint32_t i = 0; i < mDataObjects.Length(); ++i) {
    nsDataObj* dataObj = mDataObjects.ElementAt(i);
    hr = dataObj->GetData(&fe, &workingmedium);
    if (hr != S_OK) {
      switch (hr) {
        case DV_E_FORMATETC:
          continue;
        default:
          return hr;
      }
    }
    // Now we need to pull out the text
    CharT* buffer = static_cast<CharT*>(GlobalLock(workingmedium.hGlobal));
    if (buffer == nullptr) {
      return E_FAIL;
    }
    text = buffer;
    GlobalUnlock(workingmedium.hGlobal);
    ReleaseStgMedium(&workingmedium);
    // Now put the text into our buffer
    mozilla::CheckedInt<size_t> alloclen =
        mozilla::CheckedInt<size_t>(text.Length()) * sizeof(CharT);
    mozilla::CheckedInt<size_t> totalsize = alloclen + buffersize;
    if (!totalsize.isValid()) {
      return E_FAIL;
    }
    MOZ_ASSERT(alloclen.isValid());
    HGLOBAL reallocedGlobalMemory =
        ::GlobalReAlloc(hGlobalMemory, totalsize.value(), GHND);
    if (reallocedGlobalMemory == nullptr) {
      // hGlobalMemory is still allocated but will be freed here.
      return E_FAIL;
    }
    hGlobalMemory = reallocedGlobalMemory;
    auto* tmemory = (char*)::GlobalLock(hGlobalMemory);
    if (!tmemory) {
      return E_FAIL;
    }
    buffer = reinterpret_cast<CharT*>(tmemory + buffersize);
    buffer--;  // Overwrite the preceding null
    memcpy(buffer, text.get(), alloclen.value());
    GlobalUnlock(hGlobalMemory);
    buffersize = totalsize.value();
  }
  pSTM->tymed = TYMED_HGLOBAL;
  pSTM->pUnkForRelease = nullptr;  // Caller gets to free the data
  pSTM->hGlobal = hGlobalMemory;
  freeOnError.release();
  return S_OK;
}

HRESULT nsDataObjCollection::GetFileDescriptors(LPFORMATETC pFE,
                                                LPSTGMEDIUM pSTM,
                                                bool aIsWideChar) {
  STGMEDIUM workingmedium;
  FORMATETC fe = *pFE;
  HGLOBAL hGlobalMemory;
  HRESULT hr;
  size_t buffersize = sizeof(UINT);
  size_t alloclen =
      aIsWideChar ? sizeof(FILEDESCRIPTORW) : sizeof(FILEDESCRIPTORA);

  hGlobalMemory = GlobalAlloc(GHND, buffersize);
  auto freeOnError =
      mozilla::MakeScopeExit([&]() { GlobalFree(hGlobalMemory); });

  for (uint32_t i = 0; i < mDataObjects.Length(); ++i) {
    nsDataObj* dataObj = mDataObjects.ElementAt(i);
    hr = dataObj->GetData(&fe, &workingmedium);
    if (hr != S_OK) {
      switch (hr) {
        case DV_E_FORMATETC:
          continue;
        default:
          return hr;
      }
    }
    auto releaseStgMedium =
        mozilla::MakeScopeExit([&]() { ReleaseStgMedium(&workingmedium); });
    // Now we need to pull out the filedescriptor
    auto* tmemory = (char*)::GlobalLock(workingmedium.hGlobal);
    if (tmemory == nullptr) {
      return E_FAIL;
    }
    FILEDESCRIPTOR* buffer =
        reinterpret_cast<FILEDESCRIPTOR*>(tmemory + sizeof(UINT));
    auto unlockStgMedium =
        mozilla::MakeScopeExit([&]() { GlobalUnlock(workingmedium.hGlobal); });
    mozilla::CheckedInt<size_t> totalsize =
        mozilla::CheckedInt<size_t>(buffersize) + alloclen;
    if (!totalsize.isValid()) {
      return E_FAIL;
    }
    HGLOBAL reallocedGlobalMemory =
        ::GlobalReAlloc(hGlobalMemory, totalsize.value(), GHND);
    if (reallocedGlobalMemory == nullptr) {
      // hGlobalMemory is still allocated but will be freed here.
      return E_FAIL;
    }
    hGlobalMemory = reallocedGlobalMemory;
    FILEGROUPDESCRIPTOR* realbuffer =
        (FILEGROUPDESCRIPTOR*)GlobalLock(hGlobalMemory);
    if (!realbuffer) {
      return E_FAIL;
    }
    FILEDESCRIPTOR* copyloc = (FILEDESCRIPTOR*)((char*)realbuffer + buffersize);
    memcpy(copyloc, buffer, alloclen);
    realbuffer->cItems++;
    GlobalUnlock(hGlobalMemory);
    buffersize = totalsize.value();
  }
  pSTM->tymed = TYMED_HGLOBAL;
  pSTM->pUnkForRelease = nullptr;  // Caller gets to free the data
  pSTM->hGlobal = hGlobalMemory;
  freeOnError.release();
  return S_OK;
}

HRESULT nsDataObjCollection::GetFileContents(LPFORMATETC pFE,
                                             LPSTGMEDIUM pSTM) {
  ULONG num = 0;
  ULONG numwanted = (pFE->lindex == -1) ? 0 : pFE->lindex;
  FORMATETC fEtc = *pFE;
  fEtc.lindex = -1;  // We're lying to the data object so it thinks it's alone

  // The key for this data type is to figure out which data object the index
  // corresponds to and then just pass it along
  for (uint32_t i = 0; i < mDataObjects.Length(); ++i) {
    nsDataObj* dataObj = mDataObjects.ElementAt(i);
    if (dataObj->QueryGetData(&fEtc) != S_OK) continue;
    if (num == numwanted) return dataObj->GetData(pFE, pSTM);
    num++;
  }
  return DV_E_LINDEX;
}

HRESULT nsDataObjCollection::GetFirstSupporting(LPFORMATETC pFE,
                                                LPSTGMEDIUM pSTM) {
  // There is no way to pass more than one of this, so just find the first data
  // object that supports it and pass it along
  for (uint32_t i = 0; i < mDataObjects.Length(); ++i) {
    if (mDataObjects.ElementAt(i)->QueryGetData(pFE) == S_OK)
      return mDataObjects.ElementAt(i)->GetData(pFE, pSTM);
  }
  return DV_E_FORMATETC;
}