refactor: use extensible design for fetching playlist from single file

2026-07-25 12:06:11 +08:00
parent 4ed491c78a
commit f55f8c731d
9 changed files with 146 additions and 76 deletions
@@ -0,0 +1,332 @@
+// SPDX-FileCopyrightText: 2026 yyc12345 <yyc12321@outlook.com>
+//
+// SPDX-License-Identifier: MIT
+
+#include "explorerscout.h"
+
+#ifdef Q_OS_WIN
+
+#include <QDir>
+#include <QDebug>
+#include <QFileInfo>
+#include <QRegularExpression>
+
+#include <optional>
+
+#include <exdisp.h>     // IShellWindows, CLSID_ShellWindows
+#include <servprov.h>   // IServiceProvider
+#include <shlguid.h>    // SID_STopLevelBrowser
+#include <shlobj.h>
+
+// YYC MARK:
+// We use custom RAII wrappers instead of existing COM smart pointers because the
+// project may be built with MinGW, which does not have good compatibility with
+// CComPtr and Microsoft's WRL ComPtr (<wrl/client.h>).
+// Furthermore, PIDLs are not COM objects (they are freed via ILFree, not Release),
+// so no standard smart pointer covers them regardless of compiler.
+
+/// RAII wrapper for COM initialization (CoInitialize / CoUninitialize).
+/// Must be declared before any COM objects (e.g., ComPtr, UniquePidl) so that
+/// CoUninitialize runs after all COM objects are released during scope exit.
+class ComGuard {
+public:
+    ComGuard() : m_hr(CoInitialize(nullptr)) {}
+    ~ComGuard() { if (SUCCEEDED(m_hr)) CoUninitialize(); }
+    ComGuard(const ComGuard&) = delete;
+    ComGuard& operator=(const ComGuard&) = delete;
+
+    bool IsInitialized() const { return SUCCEEDED(m_hr); }
+
+private:
+    HRESULT m_hr;
+};
+
+/// RAII wrapper for COM interface pointers.
+template <typename T>
+class ComPtr {
+public:
+    ComPtr() = default;
+    ComPtr(std::nullptr_t) {}
+    ~ComPtr() { Reset(); }
+    ComPtr(const ComPtr&) = delete;
+    ComPtr& operator=(const ComPtr&) = delete;
+    ComPtr(ComPtr&& other) noexcept : m_ptr(other.m_ptr) { other.m_ptr = nullptr; }
+    ComPtr& operator=(ComPtr&& other) noexcept {
+        if (this != &other) {
+            Reset();
+            m_ptr = other.m_ptr;
+            other.m_ptr = nullptr;
+        }
+        return *this;
+    }
+
+    T* operator->() const { return m_ptr; }
+    T* Get() const { return m_ptr; }
+    T** GetAddressOf() { return &m_ptr; }
+    explicit operator bool() const { return m_ptr != nullptr; }
+    void Reset() { if (m_ptr) { m_ptr->Release(); m_ptr = nullptr; } }
+
+private:
+    T* m_ptr = nullptr;
+};
+
+/// RAII wrapper for PIDL (Item ID List).
+class UniquePidl {
+public:
+    UniquePidl() = default;
+    explicit UniquePidl(LPITEMIDLIST pidl) : m_pidl(pidl) {}
+    ~UniquePidl() { Reset(); }
+    UniquePidl(const UniquePidl&) = delete;
+    UniquePidl& operator=(const UniquePidl&) = delete;
+    UniquePidl(UniquePidl&& other) noexcept : m_pidl(other.m_pidl) { other.m_pidl = nullptr; }
+    UniquePidl& operator=(UniquePidl&& other) noexcept {
+        if (this != &other) {
+            Reset();
+            m_pidl = other.m_pidl;
+            other.m_pidl = nullptr;
+        }
+        return *this;
+    }
+
+    LPCITEMIDLIST Get() const { return m_pidl; }
+    LPITEMIDLIST* GetAddressOf() { return &m_pidl; }
+    explicit operator bool() const { return m_pidl != nullptr; }
+    void Reset() { if (m_pidl) { ILFree(m_pidl); m_pidl = nullptr; } }
+
+private:
+    LPITEMIDLIST m_pidl = nullptr;
+};
+
+/// Outputs a diagnostic warning for debugging Windows Explorer integration failures.
+static void ReportError(const QString& detail)
+{
+    qWarning("Windows Explorer file list fetch error: %s",
+             qPrintable(detail));
+}
+
+/// Normalizes a Windows directory path for case-insensitive comparison:
+/// converts to native separators, lowercases, and ensures a trailing backslash.
+static QString NormalizePath(const QString& path)
+{
+    QString result = QDir::toNativeSeparators(path).toLower();
+    if (!result.endsWith(QChar('\\'))) {
+        result += QChar('\\');
+    }
+    return result;
+}
+
+/// Checks whether the Explorer window represented by the given IDispatch is
+/// displaying the target folder. Returns its IFolderView2 on match, or null.
+static ComPtr<IFolderView2> TryMatchWindow(IDispatch* dispatch, const QString& normalizedTarget)
+{
+    // Navigate: IDispatch -> IServiceProvider -> IShellBrowser.
+    ComPtr<IServiceProvider> serviceProvider;
+    if (FAILED(dispatch->QueryInterface(IID_PPV_ARGS(serviceProvider.GetAddressOf())))) {
+        return nullptr;
+    }
+
+    ComPtr<IShellBrowser> shellBrowser;
+    if (FAILED(serviceProvider->QueryService(SID_STopLevelBrowser,
+            IID_PPV_ARGS(shellBrowser.GetAddressOf())))) {
+        return nullptr;
+    }
+
+    // IShellBrowser -> active IShellView.
+    ComPtr<IShellView> shellView;
+    if (FAILED(shellBrowser->QueryActiveShellView(shellView.GetAddressOf()))) {
+        return nullptr;
+    }
+
+    // Retrieve the folder's path via IPersistIDList.
+    ComPtr<IPersistIDList> persistIdList;
+    if (FAILED(shellView->QueryInterface(IID_PPV_ARGS(persistIdList.GetAddressOf())))) {
+        return nullptr;
+    }
+
+    UniquePidl folderPidl;
+    if (FAILED(persistIdList->GetIDList(folderPidl.GetAddressOf()))) {
+        return nullptr;
+    }
+
+    PWSTR pathStr = nullptr;
+    if (FAILED(SHGetNameFromIDList(folderPidl.Get(), SIGDN_DESKTOPABSOLUTEPARSING, &pathStr))) {
+        return nullptr;
+    }
+
+    QString windowPath = NormalizePath(QString::fromWCharArray(pathStr));
+    CoTaskMemFree(pathStr);
+
+    if (windowPath != normalizedTarget) {
+        return nullptr;
+    }
+
+    // Path matches — query IFolderView2 from the ShellView.
+    ComPtr<IFolderView2> folderView2;
+    if (FAILED(shellView->QueryInterface(IID_PPV_ARGS(folderView2.GetAddressOf())))) {
+        return nullptr;
+    }
+    return folderView2;
+}
+
+/// Tries to find a live Explorer window that is currently displaying the given
+/// folder path. Returns the IFolderView2 from that window, or an empty ComPtr.
+///
+/// Explorer's sort order is stored only in the running Explorer process's memory.
+/// Creating a new shell view via IShellFolder::CreateViewObject yields a default
+/// sort (always by name), so we must find the actual live IFolderView2 instead.
+///
+/// Reference:
+/// - https://www.stephenli.ca/getting-windows-explorers-current-directory-sort-order
+/// - https://github.com/d2phap/ImageGlass/blob/75a296287f338edcf409eee3917531b25ff5d927/v9/Components/ImageGlass.Base/FileSystem/FileFinder.cs
+/// - NuGet Package: D2Phap.EggShell
+static ComPtr<IFolderView2> FindLiveFolderView(const QString& targetFolderPath)
+{
+    // Create the Shell windows collection (all open Explorer windows).
+    ComPtr<IShellWindows> shellWindows;
+    if (FAILED(CoCreateInstance(CLSID_ShellWindows, nullptr, CLSCTX_ALL,
+            IID_PPV_ARGS(shellWindows.GetAddressOf())))) {
+        ReportError("Failed to create IShellWindows instance");
+        return nullptr;
+    }
+
+    QString normalizedTarget = NormalizePath(targetFolderPath);
+
+    // 1. Try the Desktop window first — it may contain the file the user opened.
+    {
+        VARIANT varLoc;
+        VariantInit(&varLoc);
+        varLoc.vt = VT_I4;
+        varLoc.lVal = 0;
+
+        VARIANT varLocRoot;
+        VariantInit(&varLocRoot);
+
+        long desktopHwnd = 0;
+        ComPtr<IDispatch> desktopDispatch;
+        HRESULT findHr = shellWindows->FindWindowSW(
+            &varLoc, &varLocRoot, SWC_DESKTOP,
+            &desktopHwnd, SWFO_NEEDDISPATCH,
+            desktopDispatch.GetAddressOf());
+
+        VariantClear(&varLoc);
+        VariantClear(&varLocRoot);
+
+        if (SUCCEEDED(findHr) && desktopDispatch) {
+            ComPtr<IFolderView2> result = TryMatchWindow(desktopDispatch.Get(), normalizedTarget);
+            if (result) return result;
+        }
+    }
+
+    // 2. Iterate regular Explorer windows.
+    LONG count = 0;
+    shellWindows->get_Count(&count);
+
+    for (LONG i = 0; i < count; i++) {
+        VARIANT varIndex;
+        VariantInit(&varIndex);
+        varIndex.vt = VT_I4;
+        varIndex.lVal = i;
+
+        ComPtr<IDispatch> dispatch;
+        HRESULT itemHr = shellWindows->Item(varIndex, dispatch.GetAddressOf());
+        VariantClear(&varIndex);
+
+        if (FAILED(itemHr) || !dispatch) {
+            continue;
+        }
+
+        ComPtr<IFolderView2> result = TryMatchWindow(dispatch.Get(), normalizedTarget);
+        if (result) return result;
+    }
+
+    return nullptr;
+}
+
+std::optional<PlaylistScout::ScoutResult> PlaylistScout::Explorer::scout(
+    const QUrl &url, const QStringList &allowedSuffixes) {
+    PlaylistScout::ScoutResult rv;
+
+    QFileInfo info(url.toLocalFile());
+    QString folderPath = info.path();
+    QString currentFileName = info.fileName();
+
+    // Pre-compile wildcard suffix filters into regular expressions for performance.
+    QList<QRegularExpression> nameRegexps;
+    for (const QString &pattern : allowedSuffixes) {
+        nameRegexps.append(QRegularExpression(
+            QRegularExpression::wildcardToRegularExpression(pattern),
+            QRegularExpression::CaseInsensitiveOption));
+    }
+
+    // Initialize COM. The ComGuard must be declared before any COM objects
+    // below so that CoUninitialize runs after all of them are released.
+    ComGuard comGuard;
+    if (!comGuard.IsInitialized()) {
+        ReportError("COM initialization failed");
+        return std::nullopt;
+    }
+
+    // Find a live Explorer window that is currently displaying the target folder.
+    ComPtr<IFolderView2> folderView2 = FindLiveFolderView(folderPath);
+    if (!folderView2) {
+        ReportError("No open Explorer window matches the folder: " + folderPath);
+        return std::nullopt;
+    }
+
+    // Get items already sorted in Explorer's view order, as an IShellItemArray.
+    // SVGIO_ALLVIEW returns all items; SVGIO_FLAG_VIEWORDER respects the view's sort.
+    ComPtr<IShellItemArray> itemArray;
+    if (FAILED(folderView2->Items(SVGIO_ALLVIEW | SVGIO_FLAG_VIEWORDER,
+            IID_PPV_ARGS(itemArray.GetAddressOf())))) {
+        ReportError("IFolderView2::Items(SVGIO_ALLVIEW | SVGIO_FLAG_VIEWORDER) failed");
+        return std::nullopt;
+    }
+
+    DWORD itemCount = 0;
+    itemArray->GetCount(&itemCount);
+
+    // Enumerate sorted items, filter by pattern, and build the playlist.
+    for (DWORD i = 0; i < itemCount; i++) {
+        ComPtr<IShellItem> shellItem;
+        if (FAILED(itemArray->GetItemAt(i, shellItem.GetAddressOf()))) {
+            continue;
+        }
+
+        // Get the full parsing path of the item.
+        PWSTR pathStr = nullptr;
+        if (FAILED(shellItem->GetDisplayName(SIGDN_DESKTOPABSOLUTEPARSING, &pathStr)) || !pathStr) {
+            continue;
+        }
+        QString filePath = QString::fromWCharArray(pathStr);
+        CoTaskMemFree(pathStr);
+
+        // Skip directories — the view may include folders alongside files.
+        QFileInfo fileInfo(filePath);
+        if (!fileInfo.isFile()) {
+            continue;
+        }
+
+        QString fileName = fileInfo.fileName();
+
+        // Match against compiled wildcard patterns.
+        bool matches = nameRegexps.isEmpty();
+        for (const QRegularExpression &re : std::as_const(nameRegexps)) {
+            if (re.match(fileName).hasMatch()) {
+                matches = true;
+                break;
+            }
+        }
+        if (!matches) {
+            continue;
+        }
+
+        rv.playlist.append(QUrl::fromLocalFile(filePath));
+        if (fileName == currentFileName) {
+            rv.indexHint = rv.playlist.size() - 1;
+        }
+    }
+
+    return rv;
+}
+
+#endif // Q_OS_WIN