clipboard: add SDL_ClipboardMimeTypes

This function allows to retrieve the available mime types without doing any
synthesizing.

include/SDL3/SDL_clipboard.h

@@ -42,6 +42,20 @@ extern "C" {
 
 /* Function prototypes */
 
+/**
+ *  Retrieve the list of mime types available in the clipboard.
+ *
+ * \param num_mime_types a pointer filled with the number of mime types. May be NULL.
+ * \returns a null terminated array of strings with mime types, or NULL on
+ *          failure; call SDL_GetError() for more information. This should be
+ *          freed with SDL_free() when it is no longer needed.
+ *
+ * \since This function is available since SDL 3.0.0.
+ *
+ * \sa SDL_SetClipboardData
+ */
+extern SDL_DECLSPEC char ** SDLCALL SDL_GetClipboardMimeTypes(size_t *num_mime_types);
+
 /**
  * Put UTF-8 text into the clipboard.
  *

src/dynapi/SDL_dynapi.sym

@@ -248,6 +248,7 @@ SDL3_0.0.0 {
     SDL_GetCameraSupportedFormats;
     SDL_GetCameras;
     SDL_GetClipboardData;
+    SDL_GetClipboardMimeTypes;
     SDL_GetClipboardText;
     SDL_GetClosestFullscreenDisplayMode;
     SDL_GetCurrentAudioDriver;

src/dynapi/SDL_dynapi_overrides.h

@@ -273,6 +273,7 @@
 #define SDL_GetCameraSupportedFormats SDL_GetCameraSupportedFormats_REAL
 #define SDL_GetCameras SDL_GetCameras_REAL
 #define SDL_GetClipboardData SDL_GetClipboardData_REAL
+#define SDL_GetClipboardMimeTypes SDL_GetClipboardMimeTypes_REAL
 #define SDL_GetClipboardText SDL_GetClipboardText_REAL
 #define SDL_GetClosestFullscreenDisplayMode SDL_GetClosestFullscreenDisplayMode_REAL
 #define SDL_GetCurrentAudioDriver SDL_GetCurrentAudioDriver_REAL

src/dynapi/SDL_dynapi_procs.h

@@ -294,6 +294,7 @@ SDL_DYNAPI_PROC(SDL_PropertiesID,SDL_GetCameraProperties,(SDL_Camera *a),(a),ret
 SDL_DYNAPI_PROC(SDL_CameraSpec**,SDL_GetCameraSupportedFormats,(SDL_CameraID a, int *b),(a,b),return)
 SDL_DYNAPI_PROC(SDL_CameraID*,SDL_GetCameras,(int *a),(a),return)
 SDL_DYNAPI_PROC(void*,SDL_GetClipboardData,(const char *a, size_t *b),(a,b),return)
+SDL_DYNAPI_PROC(char **,SDL_GetClipboardMimeTypes,(size_t *a),(a),return)
 SDL_DYNAPI_PROC(char*,SDL_GetClipboardText,(void),(),return)
 SDL_DYNAPI_PROC(bool,SDL_GetClosestFullscreenDisplayMode,(SDL_DisplayID a, int b, int c, float d, bool e, SDL_DisplayMode *f),(a,b,c,d,e,f),return)
 SDL_DYNAPI_PROC(const char*,SDL_GetCurrentAudioDriver,(void),(),return)

src/video/SDL_clipboard.c

@@ -53,6 +53,46 @@ void SDL_CancelClipboardData(Uint32 sequence)
     _this->clipboard_userdata = NULL;
 }
 
+char **SDL_GetClipboardMimeTypes(size_t *num_mime_types)
+{
+    SDL_VideoDevice *_this = SDL_GetVideoDevice();
+    if (!_this) {
+        SDL_SetError("Video subsystem must be initialized to query clipboard mime types");
+        return NULL;
+    }
+
+    size_t allocSize = sizeof(char *);
+    for (size_t i = 0; i < _this->num_clipboard_mime_types; i++) {
+        allocSize += strlen(_this->clipboard_mime_types[i]) + 1 + sizeof(char *);
+    }
+
+    char *ret = SDL_malloc(allocSize);
+    if (!ret)
+        return NULL;
+
+    char **pointers = (char **)ret;
+    ret += (_this->num_clipboard_mime_types + 1) * sizeof(char *);
+
+    for (size_t i = 0; i < _this->num_clipboard_mime_types; i++) {
+        pointers[i] = ret;
+
+        char *mime_type = _this->clipboard_mime_types[i];
+        /* copy the whole string including the terminating null char */
+        char c;
+        do {
+            c = *mime_type;
+            *ret = c;
+            ret++;
+            mime_type++;
+        } while (c != 0);
+    }
+
+    pointers[_this->num_clipboard_mime_types] = NULL;
+    if (num_mime_types)
+        *num_mime_types = _this->num_clipboard_mime_types;
+    return pointers;
+}
+
 bool SDL_SetClipboardData(SDL_ClipboardDataCallback callback, SDL_ClipboardCleanupCallback cleanup, void *userdata, const char **mime_types, size_t num_mime_types)
 {
     SDL_VideoDevice *_this = SDL_GetVideoDevice();