FileManager: Factorize code to handle drag-and-drop

The treeview and the breadcrumbbar used to be on one side, sharing
drag-and-drop handling and on the other side the directory view had
its one logic.

This patch factorizes both versions, in the meantime upgrading the
version used by the treeview/breadcrumbbar that was left behind. It now
uses the copy dialog :^).

Userland/Applications/FileManager/DirectoryView.cpp

@@ -659,35 +659,11 @@ void DirectoryView::setup_actions()
 
 void DirectoryView::handle_drop(GUI::ModelIndex const& index, GUI::DropEvent const& event)
 {
-    if (!event.mime_data().has_urls())
-        return;
-    auto urls = event.mime_data().urls();
-    if (urls.is_empty()) {
-        dbgln("No files to drop");
-        return;
-    }
+    auto const& target_node = node(index);
 
-    auto& target_node = node(index);
-    if (!target_node.is_directory())
-        return;
+    bool const has_accepted_drop = ::FileManager::handle_drop(event, target_node.full_path(), window()).release_value_but_fixme_should_propagate_errors();
 
-    bool had_accepted_drop = false;
-    Vector<DeprecatedString> paths_to_copy;
-    for (auto& url_to_copy : urls) {
-        if (!url_to_copy.is_valid() || url_to_copy.path() == target_node.full_path())
-            continue;
-        auto new_path = DeprecatedString::formatted("{}/{}", target_node.full_path(), LexicalPath::basename(url_to_copy.path()));
-        if (url_to_copy.path() == new_path)
-            continue;
-
-        paths_to_copy.append(url_to_copy.path());
-        had_accepted_drop = true;
-    }
-
-    if (!paths_to_copy.is_empty())
-        MUST(run_file_operation(FileOperation::Copy, paths_to_copy, target_node.full_path(), window()));
-
-    if (had_accepted_drop && on_accepted_drop)
+    if (has_accepted_drop && on_accepted_drop)
         on_accepted_drop();
 }
 

Userland/Applications/FileManager/FileUtils.cpp

@@ -8,8 +8,11 @@
 #include "FileUtils.h"
 #include "FileOperationProgressWidget.h"
 #include <AK/LexicalPath.h>
+#include <LibCore/File.h>
+#include <LibCore/MimeData.h>
 #include <LibCore/Stream.h>
 #include <LibCore/System.h>
+#include <LibGUI/Event.h>
 #include <LibGUI/MessageBox.h>
 #include <unistd.h>
 
@@ -108,4 +111,39 @@ ErrorOr<void> run_file_operation(FileOperation operation, Vector<DeprecatedStrin
     return {};
 }
 
+ErrorOr<bool> handle_drop(GUI::DropEvent const& event, DeprecatedString const& destination, GUI::Window* window)
+{
+    bool has_accepted_drop = false;
+
+    if (!event.mime_data().has_urls())
+        return has_accepted_drop;
+    auto const urls = event.mime_data().urls();
+    if (urls.is_empty()) {
+        dbgln("No files to drop");
+        return has_accepted_drop;
+    }
+
+    auto const target = LexicalPath::canonicalized_path(destination);
+
+    if (!Core::File::is_directory(target))
+        return has_accepted_drop;
+
+    Vector<DeprecatedString> paths_to_copy;
+    for (auto& url_to_copy : urls) {
+        if (!url_to_copy.is_valid() || url_to_copy.path() == target)
+            continue;
+        auto new_path = DeprecatedString::formatted("{}/{}", target, LexicalPath::basename(url_to_copy.path()));
+        if (url_to_copy.path() == new_path)
+            continue;
+
+        paths_to_copy.append(url_to_copy.path());
+        has_accepted_drop = true;
+    }
+
+    if (!paths_to_copy.is_empty())
+        TRY(run_file_operation(FileOperation::Copy, paths_to_copy, target, window));
+
+    return has_accepted_drop;
+}
+
 }

Userland/Applications/FileManager/FileUtils.h

@@ -22,4 +22,5 @@ enum class FileOperation {
 void delete_paths(Vector<DeprecatedString> const&, bool should_confirm, GUI::Window*);
 
 ErrorOr<void> run_file_operation(FileOperation, Vector<DeprecatedString> const& sources, DeprecatedString const& destination, GUI::Window*);
+ErrorOr<bool> handle_drop(GUI::DropEvent const& event, DeprecatedString const& destination, GUI::Window* window);
 }

Userland/Applications/FileManager/main.cpp

@@ -1301,34 +1301,10 @@ ErrorOr<int> run_in_windowed_mode(DeprecatedString const& initial_location, Depr
         }
     };
 
-    auto copy_urls_to_directory = [&](Vector<URL> const& urls, DeprecatedString const& directory) {
-        if (urls.is_empty()) {
-            dbgln("No files to copy");
-            return;
-        }
-        bool had_accepted_copy = false;
-        for (auto& url_to_copy : urls) {
-            if (!url_to_copy.is_valid() || url_to_copy.path() == directory)
-                continue;
-            auto new_path = DeprecatedString::formatted("{}/{}", directory, LexicalPath::basename(url_to_copy.path()));
-            if (url_to_copy.path() == new_path)
-                continue;
-
-            if (auto result = Core::File::copy_file_or_directory(url_to_copy.path(), new_path); result.is_error()) {
-                auto error_message = DeprecatedString::formatted("Could not copy {} into {}:\n {}", url_to_copy.to_deprecated_string(), new_path, static_cast<Error const&>(result.error()));
-                GUI::MessageBox::show(window, error_message, "File Manager"sv, GUI::MessageBox::Type::Error);
-            } else {
-                had_accepted_copy = true;
-            }
-        }
-        if (had_accepted_copy)
-            refresh_tree_view();
-    };
-
     breadcrumbbar.on_segment_drop = [&](size_t segment_index, GUI::DropEvent const& event) {
-        if (!event.mime_data().has_urls())
-            return;
-        copy_urls_to_directory(event.mime_data().urls(), breadcrumbbar.segment_data(segment_index));
+        bool const has_accepted_drop = handle_drop(event, breadcrumbbar.segment_data(segment_index), window).release_value_but_fixme_should_propagate_errors();
+        if (has_accepted_drop)
+            refresh_tree_view();
     };
 
     breadcrumbbar.on_segment_drag_enter = [&](size_t, GUI::DragEvent& event) {
@@ -1341,13 +1317,12 @@ ErrorOr<int> run_in_windowed_mode(DeprecatedString const& initial_location, Depr
     };
 
     tree_view.on_drop = [&](GUI::ModelIndex const& index, GUI::DropEvent const& event) {
-        if (!event.mime_data().has_urls())
-            return;
-        auto& target_node = directories_model->node(index);
-        if (!target_node.is_directory())
-            return;
-        copy_urls_to_directory(event.mime_data().urls(), target_node.full_path());
-        const_cast<GUI::DropEvent&>(event).accept();
+        auto const& target_node = directories_model->node(index);
+        bool const has_accepted_drop = handle_drop(event, target_node.full_path(), window).release_value_but_fixme_should_propagate_errors();
+        if (has_accepted_drop) {
+            refresh_tree_view();
+            const_cast<GUI::DropEvent&>(event).accept();
+        }
     };
 
     directory_view->open(initial_location);