New feature: Implement PickFolderMultiple (#135)

We have OpenFile, OpenFileMultiple, and PickFolder. It's only reasonable to also add PickFolderMultiple, since all backends support it. It does the expected thing on all backends.

src/include/nfd.h

@@ -373,6 +373,55 @@ NFD_INLINE nfdresult_t NFD_PickFolderU8_With(nfdu8char_t** outPath,
     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. */
+NFD_INLINE nfdresult_t NFD_PickFolderMultipleN_With(const nfdpathset_t** outPaths,
+                                                    const 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. */
+NFD_INLINE nfdresult_t NFD_PickFolderMultipleU8_With(const nfdpathset_t** outPaths,
+                                                     const 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.
@@ -465,6 +514,7 @@ typedef nfdnfilteritem_t nfdfilteritem_t;
 #define NFD_OpenDialogMultiple NFD_OpenDialogMultipleN
 #define NFD_SaveDialog NFD_SaveDialogN
 #define NFD_PickFolder NFD_PickFolderN
+#define NFD_PickFolderMultiple NFD_PickFolderMultipleN
 #define NFD_PathSet_GetPath NFD_PathSet_GetPathN
 #define NFD_PathSet_FreePath NFD_PathSet_FreePathN
 #define NFD_PathSet_EnumNext NFD_PathSet_EnumNextN
@@ -476,6 +526,7 @@ typedef nfdu8filteritem_t nfdfilteritem_t;
 #define NFD_OpenDialogMultiple NFD_OpenDialogMultipleU8
 #define NFD_SaveDialog NFD_SaveDialogU8
 #define NFD_PickFolder NFD_PickFolderU8
+#define NFD_PickFolderMultiple NFD_PickFolderMultipleU8
 #define NFD_PathSet_GetPath NFD_PathSet_GetPathU8
 #define NFD_PathSet_FreePath NFD_PathSet_FreePathU8
 #define NFD_PathSet_EnumNext NFD_PathSet_EnumNextU8

src/include/nfd.hpp

@@ -65,6 +65,12 @@ inline nfdresult_t PickFolder(nfdnchar_t*& outPath,
     return ::NFD_PickFolderN_With(&outPath, &args);
 }
 
+inline nfdresult_t PickFolderMultiple(const nfdpathset_t*& outPaths,
+                                      const nfdnchar_t* defaultPath = nullptr) noexcept {
+    const nfdpickfoldernargs_t args{defaultPath};
+    return ::NFD_PickFolderMultipleN_With(&outPaths, &args);
+}
+
 inline const char* GetError() noexcept {
     return ::NFD_GetError();
 }
@@ -132,6 +138,12 @@ inline nfdresult_t PickFolder(nfdu8char_t*& outPath,
     return ::NFD_PickFolderU8_With(&outPath, &args);
 }
 
+inline nfdresult_t PickFolderMultiple(const nfdpathset_t*& outPaths,
+                                      const nfdu8char_t* defaultPath = nullptr) noexcept {
+    const nfdpickfolderu8args_t args{defaultPath};
+    return ::NFD_PickFolderMultipleU8_With(&outPaths, &args);
+}
+
 namespace PathSet {
 inline nfdresult_t GetPath(const nfdpathset_t* pathSet,
                            nfdpathsetsize_t index,
@@ -237,6 +249,16 @@ inline nfdresult_t PickFolder(UniquePathN& outPath,
     return res;
 }
 
+inline nfdresult_t PickFolderMultiple(UniquePathSet& outPaths,
+                                      const nfdnchar_t* defaultPath = nullptr) noexcept {
+    const nfdpathset_t* out;
+    nfdresult_t res = PickFolderMultiple(out, defaultPath);
+    if (res == NFD_OKAY) {
+        outPaths.reset(out);
+    }
+    return res;
+}
+
 #ifdef NFD_DIFFERENT_NATIVE_FUNCTIONS
 inline nfdresult_t OpenDialog(UniquePathU8& outPath,
                               const nfdu8filteritem_t* filterList = nullptr,
@@ -284,6 +306,16 @@ inline nfdresult_t PickFolder(UniquePathU8& outPath,
     }
     return res;
 }
+
+inline nfdresult_t PickFolderMultiple(UniquePathSet& outPaths,
+                                      const nfdu8char_t* defaultPath = nullptr) noexcept {
+    const nfdpathset_t* out;
+    nfdresult_t res = PickFolderMultiple(out, defaultPath);
+    if (res == NFD_OKAY) {
+        outPaths.reset(out);
+    }
+    return res;
+}
 #endif
 
 namespace PathSet {

src/nfd_cocoa.m

@@ -437,6 +437,59 @@ 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) {
+    nfdpickfoldernargs_t args = {0};
+    args.defaultPath = 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

@@ -622,7 +622,7 @@ 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",
@@ -655,6 +655,52 @@ 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) {
+    nfdpickfoldernargs_t args{};
+    args.defaultPath = 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
+        GSList* fileList = gtk_file_chooser_get_filenames(GTK_FILE_CHOOSER(widget));
+
+        *outPaths = static_cast<void*>(fileList);
+        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);
@@ -1547,8 +1552,6 @@ 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);
@@ -1593,6 +1596,61 @@ 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) {
+    nfdpickfoldernargs_t args{};
+    args.defaultPath = 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));