New feature: Implement PickFolderMultiple

src/include/nfd.h

@@ -364,6 +364,55 @@ inline nfdresult_t NFD_PickFolderU8_With(nfdu8char_t** outPath, nfdpickfolderu8a
     return NFD_PickFolderU8_With_Impl(NFD_INTERFACE_VERSION, outPath, &args);
 }
 
+/** Select multiple folder dialog
+ *
+ *  It is the caller's responsibility to free `outPaths` via NFD_PathSet_FreeN() if this function
+ *  returns NFD_OKAY.
+ *  @param[out] outPaths
+ *  @param defaultPath If null, the operating system will decide. */
+NFD_API nfdresult_t NFD_PickFolderMultipleN(const nfdpathset_t** outPaths,
+                                            const nfdnchar_t* defaultPath);
+
+/** Select multiple folder dialog
+ *
+ *  It is the caller's responsibility to free `outPaths` via NFD_PathSet_FreeU8() if this function
+ *  returns NFD_OKAY.
+ *  @param[out] outPaths
+ *  @param defaultPath If null, the operating system will decide. */
+NFD_API nfdresult_t NFD_PickFolderMultipleU8(const nfdpathset_t** outPaths,
+                                             const nfdu8char_t* defaultPath);
+
+/** This function is a library implementation detail.  Please use NFD_PickFolderMultipleN_With()
+ * instead. */
+NFD_API nfdresult_t NFD_PickFolderMultipleN_With_Impl(nfdversion_t version,
+                                                      const nfdpathset_t** outPaths,
+                                                      const nfdpickfoldernargs_t* args);
+
+/** Select multiple folder dialog, with additional parameters.
+ *
+ *  It is the caller's responsibility to free `outPaths` via NFD_PathSet_FreeN() if this function
+ *  returns NFD_OKAY.  See documentation of nfdopendialogargs_t for details. */
+inline nfdresult_t NFD_PickFolderMultipleN_With(const nfdpathset_t** outPaths,
+                                                nfdpickfoldernargs_t args) {
+    return NFD_PickFolderMultipleN_With_Impl(NFD_INTERFACE_VERSION, outPaths, &args);
+}
+
+/** This function is a library implementation detail.  Please use NFD_PickFolderMultipleU8_With()
+ * instead.
+ */
+NFD_API nfdresult_t NFD_PickFolderMultipleU8_With_Impl(nfdversion_t version,
+                                                       const nfdpathset_t** outPaths,
+                                                       const nfdpickfolderu8args_t* args);
+
+/** Select multiple folder dialog, with additional parameters.
+ *
+ *  It is the caller's responsibility to free `outPaths` via NFD_PathSet_FreeU8() if this function
+ *  returns NFD_OKAY.  See documentation of nfdpickfolderargs_t for details. */
+inline nfdresult_t NFD_PickFolderMultipleU8_With(const nfdpathset_t** outPaths,
+                                                 nfdpickfolderu8args_t args) {
+    return NFD_PickFolderMultipleU8_With_Impl(NFD_INTERFACE_VERSION, outPaths, &args);
+}
+
 /** Get the last error
  *
  *  This is set when a function returns NFD_ERROR.

src/nfd_cocoa.m

@@ -426,6 +426,58 @@ nfdresult_t NFD_PickFolderU8_With_Impl(nfdversion_t version,
     return NFD_PickFolderN_With_Impl(version, outPath, args);
 }
 
+nfdresult_t NFD_PickFolderMultipleN(const nfdpathset_t** outPaths, const nfdnchar_t* defaultPath) {
+    const nfdpickfoldernargs_t args = {defaultPath};
+    return NFD_PickFolderMultipleN_With_Impl(NFD_INTERFACE_VERSION, outPaths, &args);
+}
+
+nfdresult_t NFD_PickFolderMultipleN_With_Impl(nfdversion_t version,
+                                              const nfdpathset_t** outPaths,
+                                              const nfdpickfoldernargs_t* args) {
+    // We haven't needed to bump the interface version yet.
+    (void)version;
+
+    nfdresult_t result = NFD_CANCEL;
+    @autoreleasepool {
+        NSWindow* keyWindow = [[NSApplication sharedApplication] keyWindow];
+
+        NSOpenPanel* dialog = [NSOpenPanel openPanel];
+        [dialog setAllowsMultipleSelection:YES];
+        [dialog setCanChooseDirectories:YES];
+        [dialog setCanCreateDirectories:YES];
+        [dialog setCanChooseFiles:NO];
+
+        // Set the starting directory
+        SetDefaultPath(dialog, args->defaultPath);
+
+        if ([dialog runModal] == NSModalResponseOK) {
+            const NSArray* urls = [dialog URLs];
+
+            if ([urls count] > 0) {
+                // have at least one URL, we return this NSArray
+                [urls retain];
+                *outPaths = (const nfdpathset_t*)urls;
+                result = NFD_OKAY;
+            }
+        }
+
+        // return focus to the key window (i.e. main window)
+        [keyWindow makeKeyAndOrderFront:nil];
+    }
+    return result;
+}
+
+nfdresult_t NFD_PickFolderMultipleU8(const nfdpathset_t** outPaths,
+                                     const nfdu8char_t* defaultPath) {
+    return NFD_PickFolderMultipleN(outPaths, defaultPath);
+}
+
+nfdresult_t NFD_PickFolderMultipleU8_With_Impl(nfdversion_t version,
+                                               const nfdpathset_t** outPaths,
+                                               const nfdpickfolderu8args_t* args) {
+    return NFD_PickFolderMultipleN_With_Impl(version, outPaths, args);
+}
+
 nfdresult_t NFD_PathSet_GetCount(const nfdpathset_t* pathSet, nfdpathsetsize_t* count) {
     const NSArray* urls = (const NSArray*)pathSet;
     *count = [urls count];

src/nfd_gtk.cpp

@@ -611,7 +611,7 @@ nfdresult_t NFD_PickFolderN_With_Impl(nfdversion_t version,
     // We haven't needed to bump the interface version yet.
     (void)version;
 
-    GtkWidget* widget = gtk_file_chooser_dialog_new("Select folder",
+    GtkWidget* widget = gtk_file_chooser_dialog_new("Select Folder",
                                                     nullptr,
                                                     GTK_FILE_CHOOSER_ACTION_SELECT_FOLDER,
                                                     "_Cancel",
@@ -644,6 +644,50 @@ nfdresult_t NFD_PickFolderU8_With_Impl(nfdversion_t version,
                                        const nfdpickfolderu8args_t* args)
     __attribute__((alias("NFD_PickFolderN_With_Impl")));
 
+nfdresult_t NFD_PickFolderMultipleN(const nfdpathset_t** outPaths, const nfdnchar_t* defaultPath) {
+    const nfdpickfoldernargs_t args{defaultPath};
+    return NFD_PickFolderMultipleN_With_Impl(NFD_INTERFACE_VERSION, outPaths, &args);
+}
+
+nfdresult_t NFD_PickFolderMultipleN_With_Impl(nfdversion_t version,
+                                              const nfdpathset_t** outPaths,
+                                              const nfdpickfoldernargs_t* args) {
+    // We haven't needed to bump the interface version yet.
+    (void)version;
+
+    GtkWidget* widget = gtk_file_chooser_dialog_new("Select Folders",
+                                                    nullptr,
+                                                    GTK_FILE_CHOOSER_ACTION_SELECT_FOLDER,
+                                                    "_Cancel",
+                                                    GTK_RESPONSE_CANCEL,
+                                                    "_Select",
+                                                    GTK_RESPONSE_ACCEPT,
+                                                    nullptr);
+
+    // guard to destroy the widget when returning from this function
+    Widget_Guard widgetGuard(widget);
+
+    /* Set the default path */
+    SetDefaultPath(GTK_FILE_CHOOSER(widget), args->defaultPath);
+
+    if (RunDialogWithFocus(GTK_DIALOG(widget)) == GTK_RESPONSE_ACCEPT) {
+        // write out the file name
+        *outPath = gtk_file_chooser_get_filename(GTK_FILE_CHOOSER(widget));
+
+        return NFD_OKAY;
+    } else {
+        return NFD_CANCEL;
+    }
+}
+
+nfdresult_t NFD_PickFolderMultipleU8(const nfdpathset_t** outPaths, const nfdu8char_t* defaultPath)
+    __attribute__((alias("NFD_PickFolderMultipleN")));
+
+nfdresult_t NFD_PickFolderMultipleU8_With_Impl(nfdversion_t version,
+                                               const nfdpathset_t** outPaths,
+                                               const nfdpickfolderu8args_t* args)
+    __attribute__((alias("NFD_PickFolderMultipleN_With_Impl")));
+
 nfdresult_t NFD_PathSet_GetCount(const nfdpathset_t* pathSet, nfdpathsetsize_t* count) {
     assert(pathSet);
     // const_cast because methods on GSList aren't const, but it should act

src/nfd_portal.cpp

@@ -120,6 +120,7 @@ constexpr const char* STR_OPEN_FILE = "Open File";
 constexpr const char* STR_OPEN_FILES = "Open Files";
 constexpr const char* STR_SAVE_FILE = "Save File";
 constexpr const char* STR_SELECT_FOLDER = "Select Folder";
+constexpr const char* STR_SELECT_FOLDERS = "Select Folders";
 constexpr const char* STR_HANDLE_TOKEN = "handle_token";
 constexpr const char* STR_MULTIPLE = "multiple";
 constexpr const char* STR_DIRECTORY = "directory";
@@ -149,6 +150,10 @@ template <>
 void AppendOpenFileQueryTitle<false, true>(DBusMessageIter& iter) {
     dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING, &STR_SELECT_FOLDER);
 }
+template <>
+void AppendOpenFileQueryTitle<true, true>(DBusMessageIter& iter) {
+    dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING, &STR_SELECT_FOLDERS);
+}
 
 void AppendSaveFileQueryTitle(DBusMessageIter& iter) {
     dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING, &STR_SAVE_FILE);
@@ -1536,8 +1541,6 @@ nfdresult_t NFD_PickFolderN_With_Impl(nfdversion_t version,
     // We haven't needed to bump the interface version yet.
     (void)version;
 
-    (void)args;  // Default path not supported for portal backend
-
     {
         dbus_uint32_t version;
         const nfdresult_t res = NFD_DBus_GetVersion(version);
@@ -1582,6 +1585,60 @@ nfdresult_t NFD_PickFolderU8_With_Impl(nfdversion_t version,
                                        const nfdpickfolderu8args_t* args)
     __attribute__((alias("NFD_PickFolderN_With_Impl")));
 
+nfdresult_t NFD_PickFolderMultipleN(const nfdpathset_t** outPaths, const nfdnchar_t* defaultPath) {
+    const nfdpickfoldernargs_t args{defaultPath};
+    return NFD_PickFolderMultipleN_With_Impl(NFD_INTERFACE_VERSION, outPaths, &args);
+}
+
+nfdresult_t NFD_PickFolderMultipleN_With_Impl(nfdversion_t version,
+                                              const nfdpathset_t** outPaths,
+                                              const nfdpickfoldernargs_t* args) {
+    // We haven't needed to bump the interface version yet.
+    (void)version;
+
+    {
+        dbus_uint32_t version;
+        const nfdresult_t res = NFD_DBus_GetVersion(version);
+        if (res != NFD_OKAY) {
+            return res;
+        }
+        if (version < 3) {
+            NFDi_SetFormattedError(
+                "The xdg-desktop-portal installed on this system does not support a folder picker; "
+                "at least version 3 of the org.freedesktop.portal.FileChooser interface is "
+                "required but the installed interface version is %u.",
+                version);
+            return NFD_ERROR;
+        }
+    }
+
+    DBusMessage* msg;
+    {
+        const nfdresult_t res = NFD_DBus_OpenFile<true, true>(msg, nullptr, 0, args->defaultPath);
+        if (res != NFD_OKAY) {
+            return res;
+        }
+    }
+
+    DBusMessageIter uri_iter;
+    const nfdresult_t res = ReadResponseUris(msg, uri_iter);
+    if (res != NFD_OKAY) {
+        dbus_message_unref(msg);
+        return res;
+    }
+
+    *outPaths = msg;
+    return NFD_OKAY;
+}
+
+nfdresult_t NFD_PickFolderMultipleU8(const nfdpathset_t** outPaths, const nfdu8char_t* defaultPath)
+    __attribute__((alias("NFD_PickFolderMultipleN")));
+
+nfdresult_t NFD_PickFolderMultipleU8_With_Impl(nfdversion_t version,
+                                               const nfdpathset_t** outPaths,
+                                               const nfdpickfolderu8args_t* args)
+    __attribute__((alias("NFD_PickFolderMultipleN_With_Impl")));
+
 nfdresult_t NFD_PathSet_GetCount(const nfdpathset_t* pathSet, nfdpathsetsize_t* count) {
     assert(pathSet);
     DBusMessage* msg = const_cast<DBusMessage*>(static_cast<const DBusMessage*>(pathSet));

src/nfd_win.cpp

@@ -636,6 +636,63 @@ nfdresult_t NFD_PickFolderN_With_Impl(nfdversion_t version,
     return NFD_OKAY;
 }
 
+nfdresult_t NFD_PickFolderMultipleN(const nfdpathset_t** outPaths, const nfdnchar_t* defaultPath) {
+    const nfdpickfoldernargs_t args{defaultPath};
+    return NFD_PickFolderMultipleN_With_Impl(NFD_INTERFACE_VERSION, outPaths, &args);
+}
+
+nfdresult_t NFD_PickFolderMultipleN_With_Impl(nfdversion_t version,
+                                              const nfdpathset_t** outPaths,
+                                              const nfdpickfoldernargs_t* args) {
+    // We haven't needed to bump the interface version yet.
+    (void)version;
+
+    ::IFileOpenDialog* fileOpenDialog;
+
+    // Create dialog
+    if (!SUCCEEDED(::CoCreateInstance(::CLSID_FileOpenDialog,
+                                      nullptr,
+                                      CLSCTX_ALL,
+                                      ::IID_IFileOpenDialog,
+                                      reinterpret_cast<void**>(&fileOpenDialog)))) {
+        NFDi_SetError("Could not create dialog.");
+        return NFD_ERROR;
+    }
+
+    Release_Guard<::IFileOpenDialog> fileOpenDialogGuard(fileOpenDialog);
+
+    // Set the default path
+    if (!SetDefaultPath(fileOpenDialog, args->defaultPath)) {
+        return NFD_ERROR;
+    }
+
+    // Allow multiple selection; only show items that are folders and on the file system
+    if (!AddOptions(fileOpenDialog,
+                    ::FOS_FORCEFILESYSTEM | ::FOS_PICKFOLDERS | ::FOS_ALLOWMULTISELECT)) {
+        return NFD_ERROR;
+    }
+
+    // Show the dialog.
+    const HRESULT result = fileOpenDialog->Show(nullptr);
+    if (SUCCEEDED(result)) {
+        ::IShellItemArray* shellItems;
+        if (!SUCCEEDED(fileOpenDialog->GetResults(&shellItems))) {
+            NFDi_SetError("Could not get shell items.");
+            return NFD_ERROR;
+        }
+
+        // save the path set to the output
+        *outPaths = static_cast<void*>(shellItems);
+
+        return NFD_OKAY;
+    } else if (result == HRESULT_FROM_WIN32(ERROR_CANCELLED)) {
+        return NFD_CANCEL;
+    } else {
+        NFDi_SetError("File dialog box show failed.");
+        return NFD_ERROR;
+    }
+}
+
 nfdresult_t NFD_PathSet_GetCount(const nfdpathset_t* pathSet, nfdpathsetsize_t* count) {
     assert(pathSet);
     // const_cast because methods on IShellItemArray aren't const, but it should act like const to
@@ -1012,6 +1069,31 @@ nfdresult_t NFD_PickFolderU8_With_Impl(nfdversion_t version,
     return res;
 }
 
+/* select multiple folders dialog */
+/* It is the caller's responsibility to free `outPaths` via NFD_PathSet_FreeU8() if this function
+ * returns NFD_OKAY. */
+nfdresult_t NFD_PickFolderMultipleU8(const nfdpathset_t** outPaths,
+                                     const nfdu8char_t* defaultPath) {
+    const nfdpickfolderu8args_t args{defaultPath};
+    return NFD_PickFolderMultipleU8_With_Impl(NFD_INTERFACE_VERSION, outPaths, &args);
+}
+
+nfdresult_t NFD_PickFolderMultipleU8_With_Impl(nfdversion_t version,
+                                               const nfdpathset_t** outPaths,
+                                               const nfdpickfolderu8args_t* args) {
+    // We haven't needed to bump the interface version yet.
+    (void)version;
+
+    // convert and normalize the default path, but only if it is not nullptr
+    FreeCheck_Guard<nfdnchar_t> defaultPathNGuard;
+    ConvertU8ToNative(args->defaultPath, defaultPathNGuard);
+    NormalizePathSeparator(defaultPathNGuard.data);
+
+    // call the native function
+    const nfdpickfoldernargs_t argsN{defaultPathNGuard.data};
+    return NFD_PickFolderMultipleN_With_Impl(NFD_INTERFACE_VERSION, outPaths, &argsN);
+}
+
 /* Get the UTF-8 path at offset index */
 /* It is the caller's responsibility to free `outPath` via NFD_FreePathU8() if this function returns
  * NFD_OKAY */