Wallpaper (macOS): add support

src/detection/wallpaper/wallpaper_apple.c

@@ -0,0 +1,31 @@
+#include "wallpaper.h"
+#include "common/settings.h"
+#include "util/apple/osascript.h"
+
+const char* ffDetectWallpaper(FF_MAYBE_UNUSED const FFinstance* instance, FFstrbuf* result)
+{
+    // https://stackoverflow.com/questions/301215/getting-desktop-background-on-mac
+
+    #ifdef FF_HAVE_SQLITE3
+
+    FF_STRBUF_AUTO_DESTROY path;
+    ffStrbufInitCopy(&path, &instance->state.platform.homeDir);
+    ffStrbufAppendS(&path, "Library/Application Support/Dock/desktoppicture.db");
+    if (ffSettingsGetSQLite3String(instance, path.chars,
+        "SELECT value\n"
+        "FROM preferences\n"
+        "JOIN data ON preferences.data_id=data.ROWID\n"
+        "JOIN pictures ON preferences.picture_id=pictures.ROWID\n"
+        "JOIN displays ON pictures.display_id=displays.ROWID\n"
+        "JOIN spaces ON pictures.space_id=spaces.ROWID\n"
+        "WHERE display_id=1 AND space_id=1 AND key=1", result)
+    )
+        return NULL;
+
+    #endif
+
+    if (!ffOsascript("tell application \"Finder\" to get POSIX path of (get desktop picture as alias)", result))
+        return "ffOsascript() failed";
+
+    return NULL;
+}