gioerror: Rely on GFileError to compute GIOErrorEnum from errno

Avoid re defining cases for GIoErrorEnum when we already handle them
through GFileError, so remove code duplication and just rely on
g_file_error_from_errno() to compute the file error and then use
g_io_error_from_file_error() to get the possible IOError.

In case it's something not handled as GFileError, we can use the same
logic as before.

This is now a safe change to do as we have covered all the supported
cases in tests.

gio/gioerror.c

@@ -73,91 +73,23 @@ G_DEFINE_QUARK (g-io-error-quark, g_io_error)
 GIOErrorEnum
 g_io_error_from_errno (gint err_no)
 {
+  GFileError file_error;
+  GIOErrorEnum io_error;
+
+  file_error = g_file_error_from_errno (err_no);
+  io_error = g_io_error_from_file_error (file_error);
+
+  if (io_error != G_IO_ERROR_FAILED)
+    return io_error;
+
   switch (err_no)
     {
-#ifdef EEXIST
-    case EEXIST:
-      return G_IO_ERROR_EXISTS;
-      break;
-#endif
-
-#ifdef EISDIR
-    case EISDIR:
-      return G_IO_ERROR_IS_DIRECTORY;
-      break;
-#endif
-
-#ifdef EACCES
-    case EACCES:
-      return G_IO_ERROR_PERMISSION_DENIED;
-      break;
-#endif
-
-#ifdef ENAMETOOLONG
-    case ENAMETOOLONG:
-      return G_IO_ERROR_FILENAME_TOO_LONG;
-      break;
-#endif
-
-#ifdef ENOENT
-    case ENOENT:
-      return G_IO_ERROR_NOT_FOUND;
-      break;
-#endif
-
-#ifdef ENOTDIR
-    case ENOTDIR:
-      return G_IO_ERROR_NOT_DIRECTORY;
-      break;
-#endif
-
-#ifdef ENXIO
-    case ENXIO:
-      return G_IO_ERROR_NOT_REGULAR_FILE;
-      break;
-#endif
-
-#ifdef ENODEV
-    case ENODEV:
-      return G_IO_ERROR_NO_SUCH_DEVICE;
-#endif
-
-#ifdef EROFS
-    case EROFS:
-      return G_IO_ERROR_READ_ONLY;
-      break;
-#endif
-
 #ifdef EMLINK
     case EMLINK:
       return G_IO_ERROR_TOO_MANY_LINKS;
       break;
 #endif
 
-#ifdef ELOOP
-    case ELOOP:
-      return G_IO_ERROR_TOO_MANY_LINKS;
-      break;
-#endif
-
-#ifdef ENOSPC
-    case ENOSPC:
-      return G_IO_ERROR_NO_SPACE;
-      break;
-#endif
-
-#ifdef ENOMEM
-    case ENOMEM:
-      return G_IO_ERROR_NO_SPACE;
-      break;
-#endif
-      
-#ifdef EINVAL
-    case EINVAL:
-      return G_IO_ERROR_INVALID_ARGUMENT;
-      break;
-#endif
-
 #ifdef ENOMSG
     case ENOMSG:
       return G_IO_ERROR_INVALID_DATA;
@@ -176,12 +108,6 @@ g_io_error_from_errno (gint err_no)
       break;
 #endif
 
-#ifdef EPERM
-    case EPERM:
-      return G_IO_ERROR_PERMISSION_DENIED;
-      break;
-#endif
-
 #ifdef ECANCELED
     case ECANCELED:
       return G_IO_ERROR_CANCELLED;
@@ -232,12 +158,6 @@ g_io_error_from_errno (gint err_no)
       break;
 #endif
 
-#ifdef ENOSYS
-    case ENOSYS:
-      return G_IO_ERROR_NOT_SUPPORTED;
-      break;
-#endif
-
 #ifdef ETIMEDOUT
     case ETIMEDOUT:
       return G_IO_ERROR_TIMED_OUT;
@@ -250,12 +170,6 @@ g_io_error_from_errno (gint err_no)
       break;
 #endif
 
-#ifdef ETXTBSY
-    case ETXTBSY:
-      return G_IO_ERROR_BUSY;
-      break;
-#endif
-
 #ifdef EWOULDBLOCK
     case EWOULDBLOCK:
       return G_IO_ERROR_WOULD_BLOCK;
@@ -269,18 +183,6 @@ g_io_error_from_errno (gint err_no)
       break;
 #endif
 
-#ifdef EMFILE
-    case EMFILE:
-      return G_IO_ERROR_TOO_MANY_OPEN_FILES;
-      break;
-#endif
-
-#ifdef ENFILE
-    case ENFILE:
-      return G_IO_ERROR_TOO_MANY_OPEN_FILES;
-      break;
-#endif
-
 #ifdef EADDRINUSE
     case EADDRINUSE:
       return G_IO_ERROR_ADDRESS_IN_USE;
@@ -311,12 +213,6 @@ g_io_error_from_errno (gint err_no)
       break;
 #endif
 
-#ifdef EPIPE
-    case EPIPE:
-      return G_IO_ERROR_BROKEN_PIPE;
-      break;
-#endif
-
 #ifdef ECONNRESET
     case ECONNRESET:
       return G_IO_ERROR_CONNECTION_CLOSED;