source/blender/editors/interface/interface_drag.cc

@@ -64,7 +64,7 @@ void UI_but_drag_set_path(uiBut *but, const char *path)
   if (but->dragflag & UI_BUT_DRAGPOIN_FREE) {
     WM_drag_data_free(but->dragtype, but->dragpoin);
   }
-  but->dragpoin = WM_drag_create_path_data(path);
+  but->dragpoin = WM_drag_create_path_data(blender::Span(&path, 1));
   but->dragflag |= UI_BUT_DRAGPOIN_FREE;
 }
 

source/blender/editors/screen/screen_ops.cc

@@ -5944,7 +5944,7 @@ static bool blend_file_drop_poll(bContext * /*C*/, wmDrag *drag, const wmEvent *
 static void blend_file_drop_copy(bContext * /*C*/, wmDrag *drag, wmDropBox *drop)
 {
   /* copy drag path to properties */
-  RNA_string_set(drop->ptr, "filepath", WM_drag_get_path(drag));
+  RNA_string_set(drop->ptr, "filepath", WM_drag_get_single_path(drag));
 }
 
 void ED_keymap_screen(wmKeyConfig *keyconf)

source/blender/editors/space_clip/space_clip.cc

@@ -536,7 +536,7 @@ static void clip_drop_copy(bContext * /*C*/, wmDrag *drag, wmDropBox *drop)
   PointerRNA itemptr;
   char dir[FILE_MAX], file[FILE_MAX];
 
-  BLI_path_split_dir_file(WM_drag_get_path(drag), dir, sizeof(dir), file, sizeof(file));
+  BLI_path_split_dir_file(WM_drag_get_single_path(drag), dir, sizeof(dir), file, sizeof(file));
 
   RNA_string_set(drop->ptr, "directory", dir);
 

source/blender/editors/space_console/space_console.cc

@@ -174,7 +174,7 @@ static bool path_drop_poll(bContext * /*C*/, wmDrag *drag, const wmEvent * /*eve
 static void path_drop_copy(bContext * /*C*/, wmDrag *drag, wmDropBox *drop)
 {
   char pathname[FILE_MAX + 2];
-  SNPRINTF(pathname, "\"%s\"", WM_drag_get_path(drag));
+  SNPRINTF(pathname, "\"%s\"", WM_drag_get_single_path(drag));
   RNA_string_set(drop->ptr, "text", pathname);
 }
 

source/blender/editors/space_file/space_file.cc

@@ -797,7 +797,7 @@ static bool filepath_drop_poll(bContext *C, wmDrag *drag, const wmEvent * /*even
 
 static void filepath_drop_copy(bContext * /*C*/, wmDrag *drag, wmDropBox *drop)
 {
-  RNA_string_set(drop->ptr, "filepath", WM_drag_get_path(drag));
+  RNA_string_set(drop->ptr, "filepath", WM_drag_get_single_path(drag));
 }
 
 /* region dropbox definition */

source/blender/editors/space_image/space_image.cc

@@ -268,7 +268,7 @@ static bool image_drop_poll(bContext *C, wmDrag *drag, const wmEvent *event)
 static void image_drop_copy(bContext * /*C*/, wmDrag *drag, wmDropBox *drop)
 {
   /* copy drag path to properties */
-  RNA_string_set(drop->ptr, "filepath", WM_drag_get_path(drag));
+  RNA_string_set(drop->ptr, "filepath", WM_drag_get_single_path(drag));
 }
 
 /* area+region dropbox definition */

source/blender/editors/space_node/space_node.cc

@@ -897,7 +897,7 @@ static void node_id_path_drop_copy(bContext *C, wmDrag *drag, wmDropBox *drop)
     return;
   }
 
-  const char *path = WM_drag_get_path(drag);
+  const char *path = WM_drag_get_single_path(drag);
   if (path) {
     RNA_string_set(drop->ptr, "filepath", path);
     RNA_struct_property_unset(drop->ptr, "name");

source/blender/editors/space_sequencer/sequencer_drag_drop.cc

@@ -249,7 +249,7 @@ static void sequencer_drop_copy(bContext *C, wmDrag *drag, wmDropBox *drop)
     return;
   }
 
-  const char *path = WM_drag_get_path(drag);
+  const char *path = WM_drag_get_single_path(drag);
   /* Path dropped. */
   if (path) {
     if (RNA_struct_find_property(drop->ptr, "filepath")) {
@@ -335,7 +335,7 @@ static void get_drag_path(const bContext *C, wmDrag *drag, char r_path[FILE_MAX]
     BLI_path_abs(r_path, BKE_main_blendfile_path_from_global());
   }
   else {
-    BLI_strncpy(r_path, WM_drag_get_path(drag), FILE_MAX);
+    BLI_strncpy(r_path, WM_drag_get_single_path(drag), FILE_MAX);
   }
 }
 

source/blender/editors/space_text/space_text.cc

@@ -316,7 +316,7 @@ static bool text_drop_poll(bContext * /*C*/, wmDrag *drag, const wmEvent * /*eve
 static void text_drop_copy(bContext * /*C*/, wmDrag *drag, wmDropBox *drop)
 {
   /* copy drag path to properties */
-  RNA_string_set(drop->ptr, "filepath", WM_drag_get_path(drag));
+  RNA_string_set(drop->ptr, "filepath", WM_drag_get_single_path(drag));
 }
 
 static bool text_drop_paste_poll(bContext * /*C*/, wmDrag *drag, const wmEvent * /*event*/)

source/blender/editors/space_view3d/space_view3d.cc

@@ -893,7 +893,7 @@ static void view3d_id_path_drop_copy(bContext *C, wmDrag *drag, wmDropBox *drop)
     RNA_struct_property_unset(drop->ptr, "filepath");
     return;
   }
-  const char *path = WM_drag_get_path(drag);
+  const char *path = WM_drag_get_single_path(drag);
   if (path) {
     RNA_string_set(drop->ptr, "filepath", path);
     RNA_struct_property_unset(drop->ptr, "image");

source/blender/windowmanager/CMakeLists.txt

@@ -210,3 +210,11 @@ blender_add_lib_nolist(bf_windowmanager "${SRC}" "${INC}" "${INC_SYS}" "${LIB}")
 
 # RNA_prototypes.h
 add_dependencies(bf_windowmanager bf_rna)
+
+if(WITH_GTESTS)
+  set(TEST_SRC
+    intern/wm_dragdrop_test.cc
+  )
+  include(GTestTesting)
+  blender_add_test_lib(bf_wm_tests "${TEST_SRC}" "${INC};${TEST_INC}" "${INC_SYS}" "${LIB}")
+endif()

source/blender/windowmanager/WM_api.hh

@@ -1424,16 +1424,32 @@ const ListBase *WM_drag_asset_list_get(const wmDrag *drag);
 
 const char *WM_drag_get_item_name(wmDrag *drag);
 
-/* Path drag and drop. */
+/* Paths drag and drop. */
 /**
- * \param path: The path to drag. Value will be copied into the drag data so the passed string may
- *              be destructed.
+ * \param paths: The paths to drag. Values will be copied into the drag data so the passed strings
+ * may be destructed.
  */
-wmDragPath *WM_drag_create_path_data(const char *path);
-const char *WM_drag_get_path(const wmDrag *drag);
+wmDragPath *WM_drag_create_path_data(blender::Span<const char *> paths);
+/* If #drag contains path data, returns the first path int he path list. */
+const char *WM_drag_get_single_path(const wmDrag *drag);
+/* If #drag contains path data, returns the first path in the path list that maches a
+ * a `file_type`.*/
+/*
+ * \param drag: The drag that could contain drag path data.
+ * \param file_type: `eFileSel_File_Types` bit flag
+ */
+const char *WM_drag_get_single_path(const wmDrag *drag, int file_type);
+blender::Span<std::string> WM_drag_get_paths(const wmDrag *drag);
+/* If #drag contains path data, returns if any file path match a `file_type`.*/
+/*
+ * \param drag: The drag that could contain drag path data.
+ * \param file_type: `eFileSel_File_Types` bit flag
+ */
+bool WM_drag_has_path_file_type(const wmDrag *drag, int file_type);
 /**
  * Note that even though the enum return type uses bit-flags, this should never have multiple
- * type-bits set, so `ELEM()` like comparison is possible.
+ * type-bits set, so `ELEM()` like comparison is possible. To check all paths or to do a bit-flag
+ * check use `WM_drag_has_path_file_type(drag,file_type)` instead.
  */
 int /* eFileSel_File_Types */ WM_drag_get_path_file_type(const wmDrag *drag);
 

source/blender/windowmanager/WM_types.hh

@@ -111,6 +111,7 @@ struct wmWindowManager;
 
 #include "BLI_compiler_attrs.h"
 #include "BLI_utildefines.h"
+#include "BLI_vector.hh"
 #include "DNA_listBase.h"
 #include "DNA_uuid_types.h"
 #include "DNA_vec_types.h"
@@ -1179,10 +1180,12 @@ struct wmDragAssetListItem {
 };
 
 struct wmDragPath {
-  char *path;
-  /* Note that even though the enum type uses bit-flags, this should never have multiple type-bits
-   * set, so `ELEM()` like comparison is possible. */
-  int file_type; /* eFileSel_File_Types */
+  blender::Vector<std::string> paths;
+  /* File type of each path in #paths. */
+  blender::Vector<int> file_types; /* eFileSel_File_Types */
+  /* Bit flag of file types in #paths. */
+  int file_types_bit_flag; /* eFileSel_File_Types */
+  std::string tooltip;
 };
 
 struct wmDragGreasePencilLayer {

source/blender/windowmanager/intern/wm_dragdrop.cc

@@ -60,6 +60,7 @@
 #include "wm_event_system.h"
 #include "wm_window.hh"
 
+#include <fmt/format.h>
 /* ****************************************************** */
 
 static ListBase dropboxes = {nullptr, nullptr};
@@ -762,29 +763,80 @@ const ListBase *WM_drag_asset_list_get(const wmDrag *drag)
   return &drag->asset_items;
 }
 
-wmDragPath *WM_drag_create_path_data(const char *path)
+wmDragPath *WM_drag_create_path_data(blender::Span<const char *> paths)
 {
+  BLI_assert(!paths.is_empty());
   wmDragPath *path_data = MEM_new<wmDragPath>("wmDragPath");
-  path_data->path = BLI_strdup(path);
-  path_data->file_type = ED_path_extension_type(path);
+
+  for (const char *path : paths) {
+    path_data->paths.append(path);
+    path_data->file_types_bit_flag |= ED_path_extension_type(path);
+    path_data->file_types.append(ED_path_extension_type(path));
+  }
+
+  path_data->tooltip = path_data->paths[0];
+
+  if (path_data->paths.size() > 1) {
+    std::string path_count = std::to_string(path_data->paths.size());
+    path_data->tooltip = fmt::format(TIP_("Dragging {} files"), path_count);
+  }
+
   return path_data;
 }
 
 static void wm_drag_free_path_data(wmDragPath **path_data)
 {
-  MEM_freeN((*path_data)->path);
   MEM_delete(*path_data);
   *path_data = nullptr;
 }
 
-const char *WM_drag_get_path(const wmDrag *drag)
+const char *WM_drag_get_single_path(const wmDrag *drag)
 {
   if (drag->type != WM_DRAG_PATH) {
     return nullptr;
   }
 
   const wmDragPath *path_data = static_cast<const wmDragPath *>(drag->poin);
-  return path_data->path;
+  return path_data->paths[0].c_str();
+}
+
+const char *WM_drag_get_single_path(const wmDrag *drag, int file_type)
+{
+  if (drag->type != WM_DRAG_PATH) {
+    return nullptr;
+  }
+  const wmDragPath *path_data = static_cast<const wmDragPath *>(drag->poin);
+  auto const file_types = path_data->file_types;
+
+  auto itr = std::find_if(
+      file_types.begin(), file_types.end(), [file_type](const int file_fype_test) {
+        return file_fype_test & file_type;
+      });
+
+  if (itr == file_types.end()) {
+    return nullptr;
+  }
+  const int index = itr - file_types.begin();
+  return path_data->paths[index].c_str();
+}
+
+bool WM_drag_has_path_file_type(const wmDrag *drag, int file_type)
+{
+  if (drag->type != WM_DRAG_PATH) {
+    return false;
+  }
+  const wmDragPath *path_data = static_cast<const wmDragPath *>(drag->poin);
+  return bool(path_data->file_types_bit_flag & file_type);
+}
+
+blender::Span<std::string> WM_drag_get_paths(const wmDrag *drag)
+{
+  if (drag->type != WM_DRAG_PATH) {
+    return blender::Span<std::string>();
+  }
+
+  const wmDragPath *path_data = static_cast<const wmDragPath *>(drag->poin);
+  return path_data->paths.as_span();
 }
 
 int WM_drag_get_path_file_type(const wmDrag *drag)
@@ -794,7 +846,7 @@ int WM_drag_get_path_file_type(const wmDrag *drag)
   }
 
   const wmDragPath *path_data = static_cast<const wmDragPath *>(drag->poin);
-  return path_data->file_type;
+  return path_data->file_types[0];
 }
 
 /* ************** draw ***************** */
@@ -848,7 +900,7 @@ const char *WM_drag_get_item_name(wmDrag *drag)
     }
     case WM_DRAG_PATH: {
       const wmDragPath *path_drag_data = static_cast<const wmDragPath *>(drag->poin);
-      return path_drag_data->path;
+      return path_drag_data->tooltip.c_str();
     }
     case WM_DRAG_NAME:
       return static_cast<const char *>(drag->poin);

source/blender/windowmanager/intern/wm_dragdrop_test.cc

@@ -0,0 +1,93 @@
+/* SPDX-FileCopyrightText: 2023 Blender Authors
+ *
+ * SPDX-License-Identifier: Apache-2.0 */
+
+#include "testing/testing.h"
+
+/* #eFileSel_File_Types. */
+#include "DNA_space_types.h"
+
+#include "WM_api.hh"
+#include "WM_types.hh"
+
+namespace blender::tests {
+
+TEST(wm_drag, wmDragPath)
+{
+  {
+    /**
+     * NOTE: `WM_drag_create_path_data` gets the `file_type` from the first path in `paths` and
+     * only needs its extension, so there is no need to describe a full path here that can have a
+     * different format on Windows or Linux. However callers must ensure that they are valid paths.
+     */
+    blender::Vector<const char *> paths{"text_file.txt"};
+    wmDragPath *path_data = WM_drag_create_path_data(paths);
+    blender::Vector<std::string> expected_file_paths{"text_file.txt"};
+
+    EXPECT_EQ(path_data->paths.size(), 1);
+    EXPECT_EQ(path_data->tooltip, "text_file.txt");
+    EXPECT_EQ(path_data->paths, expected_file_paths);
+
+    /** Test `wmDrag` path data getters. */
+    wmDrag drag;
+    drag.type = WM_DRAG_PATH;
+    drag.poin = path_data;
+    EXPECT_STREQ(WM_drag_get_single_path(&drag), "text_file.txt");
+    EXPECT_EQ(WM_drag_get_path_file_type(&drag), FILE_TYPE_TEXT);
+    EXPECT_EQ(WM_drag_get_paths(&drag), expected_file_paths.as_span());
+    EXPECT_STREQ(WM_drag_get_single_path(&drag, FILE_TYPE_TEXT), "text_file.txt");
+    EXPECT_EQ(WM_drag_get_single_path(&drag, FILE_TYPE_BLENDER), nullptr);
+    EXPECT_TRUE(
+        WM_drag_has_path_file_type(&drag, FILE_TYPE_BLENDER | FILE_TYPE_TEXT | FILE_TYPE_IMAGE));
+    EXPECT_FALSE(WM_drag_has_path_file_type(&drag, FILE_TYPE_BLENDER | FILE_TYPE_IMAGE));
+    MEM_delete(path_data);
+  }
+  {
+    blender::Vector<const char *> paths = {"blender.blend", "text_file.txt", "image.png"};
+    wmDragPath *path_data = WM_drag_create_path_data(paths);
+    blender::Vector<std::string> expected_file_paths = {
+        "blender.blend", "text_file.txt", "image.png"};
+
+    EXPECT_EQ(path_data->paths.size(), 3);
+    EXPECT_EQ(path_data->tooltip, "Dragging 3 files");
+    EXPECT_EQ(path_data->paths, expected_file_paths);
+
+    /** Test `wmDrag` path data getters. */
+    wmDrag drag;
+    drag.type = WM_DRAG_PATH;
+    drag.poin = path_data;
+    EXPECT_STREQ(WM_drag_get_single_path(&drag), "blender.blend");
+    EXPECT_EQ(WM_drag_get_path_file_type(&drag), FILE_TYPE_BLENDER);
+    EXPECT_EQ(WM_drag_get_paths(&drag), expected_file_paths.as_span());
+    EXPECT_STREQ(WM_drag_get_single_path(&drag, FILE_TYPE_BLENDER), "blender.blend");
+    EXPECT_STREQ(WM_drag_get_single_path(&drag, FILE_TYPE_IMAGE), "image.png");
+    EXPECT_STREQ(WM_drag_get_single_path(&drag, FILE_TYPE_TEXT), "text_file.txt");
+    EXPECT_STREQ(
+        WM_drag_get_single_path(&drag, FILE_TYPE_BLENDER | FILE_TYPE_TEXT | FILE_TYPE_IMAGE),
+        "blender.blend");
+    EXPECT_STREQ(WM_drag_get_single_path(&drag, FILE_TYPE_TEXT | FILE_TYPE_IMAGE),
+                 "text_file.txt");
+    EXPECT_EQ(WM_drag_get_single_path(&drag, FILE_TYPE_ASSET), nullptr);
+    EXPECT_TRUE(
+        WM_drag_has_path_file_type(&drag, FILE_TYPE_BLENDER | FILE_TYPE_TEXT | FILE_TYPE_IMAGE));
+    EXPECT_TRUE(WM_drag_has_path_file_type(&drag, FILE_TYPE_BLENDER | FILE_TYPE_IMAGE));
+    EXPECT_TRUE(WM_drag_has_path_file_type(&drag, FILE_TYPE_IMAGE));
+    EXPECT_FALSE(WM_drag_has_path_file_type(&drag, FILE_TYPE_ASSET));
+    MEM_delete(path_data);
+  }
+  {
+    /** Test `wmDrag` path data getters when the drag type is different to `WM_DRAG_PATH`. */
+    wmDrag drag;
+    drag.type = WM_DRAG_COLOR;
+    EXPECT_EQ(WM_drag_get_single_path(&drag), nullptr);
+    EXPECT_EQ(WM_drag_get_path_file_type(&drag), 0);
+    EXPECT_EQ(WM_drag_get_paths(&drag).size(), 0);
+    EXPECT_EQ(WM_drag_get_single_path(
+                  &drag, FILE_TYPE_BLENDER | FILE_TYPE_IMAGE | FILE_TYPE_TEXT | FILE_TYPE_ASSET),
+              nullptr);
+    EXPECT_FALSE(WM_drag_has_path_file_type(
+        &drag, FILE_TYPE_BLENDER | FILE_TYPE_IMAGE | FILE_TYPE_TEXT | FILE_TYPE_ASSET));
+  }
+}
+
+}  // namespace blender::tests

source/blender/windowmanager/intern/wm_window.cc

@@ -15,6 +15,8 @@
 #include <cstring>
 #include <thread>
 
+#include "CLG_log.h"
+
 #include "DNA_listBase.h"
 #include "DNA_screen_types.h"
 #include "DNA_windowmanager_types.h"
@@ -1649,14 +1651,17 @@ static bool ghost_event_proc(GHOST_EventHandle ghost_event, GHOST_TUserDataPtr C
       if (ddd->dataType == GHOST_kDragnDropTypeFilenames) {
         const GHOST_TStringArray *stra = static_cast<const GHOST_TStringArray *>(ddd->data);
 
-        for (int a = 0; a < stra->count; a++) {
-          printf("drop file %s\n", stra->strings[a]);
-          /* try to get icon type from extension */
-          int icon = ED_file_extension_icon((char *)stra->strings[a]);
-          wmDragPath *path_data = WM_drag_create_path_data((char *)stra->strings[a]);
+        if (stra->count) {
+          CLOG_INFO(WM_LOG_EVENTS, 1, "Drop %d files:", stra->count);
+          for (const char *path : blender::Span((char **)stra->strings, stra->count)) {
+            CLOG_INFO(WM_LOG_EVENTS, 1, "%s", path);
+          }
+          /* Try to get icon type from extension of the first path. */
+          int icon = ED_file_extension_icon((char *)stra->strings[0]);
+          wmDragPath *path_data = WM_drag_create_path_data(
+              blender::Span((char **)stra->strings, stra->count));
           WM_event_start_drag(C, icon, WM_DRAG_PATH, path_data, 0.0, WM_DRAG_NOP);
           /* Void pointer should point to string, it makes a copy. */
-          break; /* only one drop element supported now */
         }
       }