[gnome-builder/wip/gtk4-port] libide/threading: add helper to merge with dest_fd check

[Christian Hergert <chergert src gnome org>]

commit 4a4e73411cc7203ff04ac36a2c8d42e470f97617
Author: Christian Hergert <chergert redhat com>
Date:   Fri Jun 17 01:01:34 2022 -0700

    libide/threading: add helper to merge with dest_fd check

 src/libide/threading/ide-unix-fd-map.c | 36 ++++++++++++++++++++++++++++++++++
 src/libide/threading/ide-unix-fd-map.h |  6 +++++-
 2 files changed, 41 insertions(+), 1 deletion(-)
---
diff --git a/src/libide/threading/ide-unix-fd-map.c b/src/libide/threading/ide-unix-fd-map.c
index 75946f4b7..de839480b 100644
--- a/src/libide/threading/ide-unix-fd-map.c
+++ b/src/libide/threading/ide-unix-fd-map.c
@@ -382,3 +382,39 @@ ide_unix_fd_map_open_file (IdeUnixFDMap  *self,
 
   return TRUE;
 }
+
+gboolean
+ide_unix_fd_map_steal_from (IdeUnixFDMap  *self,
+                            IdeUnixFDMap  *other,
+                            GError       **error)
+{
+  g_return_val_if_fail (IDE_IS_UNIX_FD_MAP (self), FALSE);
+  g_return_val_if_fail (IDE_IS_UNIX_FD_MAP (other), FALSE);
+
+  for (guint i = 0; i < other->map->len; i++)
+    {
+      IdeUnixFDMapItem *item = &g_array_index (other->map, IdeUnixFDMapItem, i);
+
+      if (item->source_fd != -1)
+        {
+          for (guint j = 0; j < self->map->len; j++)
+            {
+              IdeUnixFDMapItem *ele = &g_array_index (self->map, IdeUnixFDMapItem, j);
+
+              if (ele->dest_fd == item->dest_fd && ele->source_fd != -1)
+                {
+                  g_set_error (error,
+                               G_IO_ERROR,
+                               G_IO_ERROR_INVALID_ARGUMENT,
+                               "Attempt to merge overlapping destination FDs for %d",
+                               item->dest_fd);
+                  return FALSE;
+                }
+            }
+
+          ide_unix_fd_map_take (self, ide_steal_fd (&item->source_fd), item->dest_fd);
+        }
+    }
+
+  return TRUE;
+}
diff --git a/src/libide/threading/ide-unix-fd-map.h b/src/libide/threading/ide-unix-fd-map.h
index 1c13bdc07..c3c4f0e96 100644
--- a/src/libide/threading/ide-unix-fd-map.h
+++ b/src/libide/threading/ide-unix-fd-map.h
@@ -50,6 +50,10 @@ int           ide_unix_fd_map_steal_stdout    (IdeUnixFDMap  *self);
 IDE_AVAILABLE_IN_ALL
 int           ide_unix_fd_map_steal_stderr    (IdeUnixFDMap  *self);
 IDE_AVAILABLE_IN_ALL
+gboolean      ide_unix_fd_map_steal_from      (IdeUnixFDMap  *self,
+                                               IdeUnixFDMap  *other,
+                                               GError       **error);
+IDE_AVAILABLE_IN_ALL
 int           ide_unix_fd_map_peek            (IdeUnixFDMap  *self,
                                                guint          index,
                                                int           *dest_fd);
@@ -73,7 +77,7 @@ gboolean      ide_unix_fd_map_open_file       (IdeUnixFDMap  *self,
                                                int            dest_fd,
                                                GError       **error);
 IDE_AVAILABLE_IN_ALL
-int           ide_unix_fd_map_get_max_dest_fd (IdeUnixFDMap *self);
+int           ide_unix_fd_map_get_max_dest_fd (IdeUnixFDMap  *self);
 IDE_AVAILABLE_IN_ALL
 gboolean      ide_unix_fd_map_stdin_isatty    (IdeUnixFDMap  *self);
 IDE_AVAILABLE_IN_ALL