Implement moving of a single file system entry to the trash

This implements the operation for Windows, macOS, and Unix, for now
only as a private API (since QFileSystemEngine is private). This adds
the capability as a testable function; public API to be agreed on and
added in a separate commit.

The Unix implementation follows the freedesktop.org specification [1]
version 1.0.

[1] https://specifications.freedesktop.org/trash-spec/trashspec-1.0.html

On macOS and Windows, native APIs are used, with each having some
limitations:

* on macOS, the file in the trash won't have a "put back" option,
  as we don't use Finder automation, for the reasons provided in the
  comments
* on Windows, we might not be able to use the modern IFileOperation
  API, e.g. if Qt is built with mingw which doesn't seem to provide
  the interface definition; the fallback doesn't provide access to
  the file name in the trash

The test case creates files and directories, and moves them to the
trash. As part of the cleanup routine, it deletes all file system
entries created. If run on Windows without IFileOperations support,
this will add a file in the trash for each test run, filling up
hard drive space.

Task-number: QTBUG-47703
Change-Id: I5f5f4e578be2f45d7da84f70a03acbe1a12a1231
Reviewed-by: Vitaly Fanaskov <vitaly.fanaskov@qt.io>

1 files changed, 192 insertions, 0 deletions

diff --git a/src/corelib/io/qfilesystemengine_win.cpp b/src/corelib/io/qfilesystemengine_win.cpp
index 0579872f8d..71a0e36693 100644
--- a/src/corelib/io/qfilesystemengine_win.cpp
+++ b/src/corelib/io/qfilesystemengine_win.cpp
@@ -41,6 +41,7 @@
 #include "qoperatingsystemversion.h"
 #include "qplatformdefs.h"
 #include "qsysinfo.h"
+#include "qscopeguard.h"
 #include "private/qabstractfileengine_p.h"
 #include "private/qfsfileengine_p.h"
 #include <private/qsystemlibrary_p.h>
@@ -59,6 +60,8 @@
 #include <objbase.h>
 #ifndef Q_OS_WINRT
 #  include <shlobj.h>
+#  include <shobjidl.h>
+#  include <shellapi.h>
 #  include <lm.h>
 #  include <accctrl.h>
 #endif
@@ -422,6 +425,104 @@ static inline bool getFindData(QString path, WIN32_FIND_DATA &findData)
     return false;
 }
 
+#if defined(__IFileOperation_INTERFACE_DEFINED__)
+class FileOperationProgressSink : public IFileOperationProgressSink
+{
+public:
+    FileOperationProgressSink()
+    : ref(1)
+    {}
+    virtual ~FileOperationProgressSink() {}
+
+    ULONG STDMETHODCALLTYPE AddRef()
+    {
+        return ++ref;
+    }
+    ULONG STDMETHODCALLTYPE Release()
+    {
+        if (--ref == 0) {
+            delete this;
+            return 0;
+        }
+        return ref;
+    }
+    HRESULT STDMETHODCALLTYPE QueryInterface(REFIID iid, void **ppvObject)
+    {
+        if (!ppvObject)
+            return E_POINTER;
+
+        *ppvObject = nullptr;
+
+        if (iid == __uuidof(IUnknown)) {
+            *ppvObject = static_cast<IUnknown*>(this);
+        } else if (iid == __uuidof(IFileOperationProgressSink)) {
+            *ppvObject = static_cast<IFileOperationProgressSink*>(this);
+        }
+
+        if (*ppvObject) {
+            AddRef();
+            return S_OK;
+        }
+
+        return E_NOINTERFACE;
+    }
+
+    HRESULT STDMETHODCALLTYPE StartOperations()
+    { return S_OK; }
+    HRESULT STDMETHODCALLTYPE FinishOperations(HRESULT)
+    { return S_OK; }
+    HRESULT STDMETHODCALLTYPE PreRenameItem(DWORD, IShellItem *, LPCWSTR)
+    { return S_OK; }
+    HRESULT STDMETHODCALLTYPE PostRenameItem(DWORD, IShellItem *, LPCWSTR, HRESULT, IShellItem *)
+    { return S_OK; }
+    HRESULT STDMETHODCALLTYPE PreMoveItem(DWORD, IShellItem *, IShellItem *, LPCWSTR)
+    { return S_OK; }
+    HRESULT STDMETHODCALLTYPE PostMoveItem(DWORD, IShellItem *, IShellItem *, LPCWSTR, HRESULT,
+                                           IShellItem *)
+    { return S_OK; }
+    HRESULT STDMETHODCALLTYPE PreCopyItem(DWORD, IShellItem *, IShellItem *, LPCWSTR )
+    { return S_OK; }
+    HRESULT STDMETHODCALLTYPE PostCopyItem(DWORD, IShellItem *, IShellItem *, LPCWSTR, HRESULT,
+                                           IShellItem *)
+    { return S_OK; }
+    HRESULT STDMETHODCALLTYPE PreDeleteItem(DWORD dwFlags, IShellItem *)
+    {
+        // stop the operation if the file will be deleted rather than trashed
+        return (dwFlags & TSF_DELETE_RECYCLE_IF_POSSIBLE) ? S_OK : E_FAIL;
+    }
+    HRESULT STDMETHODCALLTYPE PostDeleteItem(DWORD /* dwFlags */, IShellItem * /* psiItem */,
+                                             HRESULT /* hrDelete */, IShellItem *psiNewlyCreated)
+    {
+        if (psiNewlyCreated) {
+            wchar_t *pszName = nullptr;
+            psiNewlyCreated->GetDisplayName(SIGDN_FILESYSPATH, &pszName);
+            if (pszName) {
+                targetPath = QString::fromWCharArray(pszName);
+                CoTaskMemFree(pszName);
+            }
+        }
+        return S_OK;
+    }
+    HRESULT STDMETHODCALLTYPE PreNewItem(DWORD, IShellItem *, LPCWSTR)
+    { return S_OK; }
+    HRESULT STDMETHODCALLTYPE PostNewItem(DWORD, IShellItem *, LPCWSTR, LPCWSTR, DWORD, HRESULT,
+                                          IShellItem *)
+    { return S_OK; }
+    HRESULT STDMETHODCALLTYPE UpdateProgress(UINT,UINT)
+    { return S_OK; }
+    HRESULT STDMETHODCALLTYPE ResetTimer()
+    { return S_OK; }
+    HRESULT STDMETHODCALLTYPE PauseTimer()
+    { return S_OK; }
+    HRESULT STDMETHODCALLTYPE ResumeTimer()
+    { return S_OK; }
+
+    QString targetPath;
+private:
+    ULONG ref;
+};
+#endif
+
 bool QFileSystemEngine::uncListSharesOnServer(const QString &server, QStringList *list)
 {
     DWORD res = ERROR_NOT_SUPPORTED;
@@ -1431,6 +1532,97 @@ bool QFileSystemEngine::removeFile(const QFileSystemEntry &entry, QSystemError &
     return ret;
 }
 
+/*
+    If possible, we use the IFileOperation implementation, which allows us to determine
+    the location of the object in the trash.
+    If not (likely on mingw), we fall back to the old API, which won't allow us to know
+    that.
+*/
+//static
+bool QFileSystemEngine::moveFileToTrash(const QFileSystemEntry &source,
+                                        QFileSystemEntry &newLocation, QSystemError &error)
+{
+#ifndef Q_OS_WINRT
+    // we need the "display name" of the file, so can't use nativeFilePath
+    const QString sourcePath = QDir::toNativeSeparators(source.filePath());
+
+#  if defined(__IFileOperation_INTERFACE_DEFINED__)
+    CoInitialize(NULL);
+    IFileOperation *pfo = nullptr;
+    IShellItem *deleteItem = nullptr;
+    FileOperationProgressSink *sink = nullptr;
+    HRESULT hres = E_FAIL;
+
+    auto coUninitialize = qScopeGuard([&](){
+        if (sink)
+            sink->Release();
+        if (deleteItem)
+            deleteItem->Release();
+        if (pfo)
+            pfo->Release();
+        CoUninitialize();
+        if (!SUCCEEDED(hres))
+            error = QSystemError(hres, QSystemError::NativeError);
+    });
+
+    hres = CoCreateInstance(CLSID_FileOperation, nullptr, CLSCTX_ALL, IID_PPV_ARGS(&pfo));
+    if (!pfo)
+        return false;
+    pfo->SetOperationFlags(FOF_ALLOWUNDO | FOFX_RECYCLEONDELETE | FOF_NOCONFIRMATION
+                           | FOF_SILENT | FOF_NOERRORUI);
+    hres = SHCreateItemFromParsingName(reinterpret_cast<const wchar_t*>(sourcePath.utf16()),
+                                       nullptr, IID_PPV_ARGS(&deleteItem));
+    if (!deleteItem)
+        return false;
+    sink = new FileOperationProgressSink;
+    hres = pfo->DeleteItem(deleteItem, static_cast<IFileOperationProgressSink*>(sink));
+    if (!SUCCEEDED(hres))
+        return false;
+    hres = pfo->PerformOperations();
+    if (!SUCCEEDED(hres))
+        return false;
+    newLocation = QFileSystemEntry(sink->targetPath);
+
+#  else // no IFileOperation in SDK (mingw, likely) - fall back to SHFileOperation
+
+    // double null termination needed, so can't use QString::utf16
+    QVarLengthArray<wchar_t, MAX_PATH + 1> winFile(sourcePath.length() + 2);
+    sourcePath.toWCharArray(winFile.data());
+    winFile[sourcePath.length()] = wchar_t{};
+    winFile[sourcePath.length() + 1] = wchar_t{};
+
+    SHFILEOPSTRUCTW operation;
+    operation.hwnd = nullptr;
+    operation.wFunc = FO_DELETE;
+    operation.pFrom = winFile.constData();
+    operation.pTo = nullptr;
+    operation.fFlags = FOF_ALLOWUNDO | FOF_NO_UI;
+    operation.fAnyOperationsAborted = FALSE;
+    operation.hNameMappings = nullptr;
+    operation.lpszProgressTitle = nullptr;
+
+    int result = SHFileOperation(&operation);
+    if (result != 0) {
+        error = QSystemError(result, QSystemError::NativeError);
+        return false;
+    }
+    /*
+        This implementation doesn't let us know where the file ended up, even if
+        we would specify FOF_WANTMAPPINGHANDLE | FOF_RENAMEONCOLLISION, as
+        FOF_RENAMEONCOLLISION has no effect unless files are moved, copied, or renamed.
+    */
+    Q_UNUSED(newLocation);
+#  endif // IFileOperation fallback
+    return true;
+
+#else // Q_OS_WINRT
+    Q_UNUSED(source);
+    Q_UNUSED(newLocation);
+    Q_UNUSED(error);
+    return false;
+#endif
+}
+
 //static
 bool QFileSystemEngine::setPermissions(const QFileSystemEntry &entry, QFile::Permissions permissions, QSystemError &error,
                                        QFileSystemMetaData *data)