Merge branch '2863-copy-file-range' into 'main'

gfile: Support copy_file_range() for file copies

Closes #2863

See merge request GNOME/glib!3328

3 files changed, 230 insertions, 10 deletions

diff --git a/gio/gfile.c b/gio/gfile.c
index 94786c84a..31da0b05e 100644
--- a/gio/gfile.c
+++ b/gio/gfile.c
@@ -2807,6 +2807,11 @@ g_file_build_attribute_list_for_copy (GFile                  *file,
   first = TRUE;
   s = g_string_new ("");
 
+  /* Always query the source file size, even though we can’t set that on the
+   * destination. This is useful for the copy functions. */
+  first = FALSE;
+  g_string_append (s, G_FILE_ATTRIBUTE_STANDARD_SIZE);
+
   if (attributes)
     {
       for (i = 0; i < attributes->n_infos; i++)
@@ -3002,6 +3007,122 @@ copy_stream_with_progress (GInputStream           *in,
   return res;
 }
 
+#ifdef HAVE_COPY_FILE_RANGE
+static gboolean
+do_copy_file_range (int      fd_in,
+                    loff_t  *off_in,
+                    int      fd_out,
+                    loff_t  *off_out,
+                    size_t   len,
+                    size_t  *bytes_transferred,
+                    GError **error)
+{
+  ssize_t result;
+
+  do
+    {
+      result = copy_file_range (fd_in, off_in, fd_out, off_out, len, 0);
+
+      if (result == -1)
+        {
+          int errsv = errno;
+
+          if (errsv == EINTR)
+            {
+              continue;
+            }
+          else if (errsv == ENOSYS || errsv == EINVAL || errsv == EOPNOTSUPP || errsv == EXDEV)
+            {
+              g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
+                                   _("Copy file range not supported"));
+            }
+          else
+            {
+              g_set_error (error, G_IO_ERROR,
+                           g_io_error_from_errno (errsv),
+                           _("Error splicing file: %s"),
+                           g_strerror (errsv));
+            }
+
+          return FALSE;
+        }
+    } while (result == -1);
+
+  g_assert (result >= 0);
+  *bytes_transferred = result;
+
+  return TRUE;
+}
+
+static gboolean
+copy_file_range_with_progress (GInputStream           *in,
+                               GFileInfo              *in_info,
+                               GOutputStream          *out,
+                               GCancellable           *cancellable,
+                               GFileProgressCallback   progress_callback,
+                               gpointer                progress_callback_data,
+                               GError                **error)
+{
+  goffset total_size, last_notified_size;
+  size_t copy_len;
+  loff_t offset_in;
+  loff_t offset_out;
+  int fd_in, fd_out;
+
+  fd_in = g_file_descriptor_based_get_fd (G_FILE_DESCRIPTOR_BASED (in));
+  fd_out = g_file_descriptor_based_get_fd (G_FILE_DESCRIPTOR_BASED (out));
+
+  g_assert (g_file_info_has_attribute (in_info, G_FILE_ATTRIBUTE_STANDARD_SIZE));
+  total_size = g_file_info_get_size (in_info);
+
+  /* Bail out if the reported size of the file is zero. It might be zero, but it
+   * might also just be a kernel file in /proc. They report their file size as
+   * zero, but then have data when you start reading. Go to the fallback code
+   * path for those. */
+  if (total_size == 0)
+    {
+      g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED,
+                   _("Copy file range not supported"));
+      return FALSE;
+    }
+
+  offset_in = offset_out = 0;
+  copy_len = total_size;
+  last_notified_size = 0;
+
+  /* Call copy_file_range() in a loop until the whole contents are copied. For
+   * smaller files, this loop will iterate only once. For larger files, the
+   * kernel (at least, kernel 6.1.6) will return after 2GB anyway, so that gives
+   * us more loop iterations and more progress reporting. */
+  while (copy_len > 0)
+    {
+      size_t n_copied;
+
+      if (g_cancellable_set_error_if_cancelled (cancellable, error) ||
+          !do_copy_file_range (fd_in, &offset_in, fd_out, &offset_out, copy_len, &n_copied, error))
+        return FALSE;
+
+      if (n_copied == 0)
+        break;
+
+      g_assert (n_copied <= copy_len);
+      copy_len -= n_copied;
+
+      if (progress_callback)
+        {
+          progress_callback (offset_in, total_size, progress_callback_data);
+          last_notified_size = total_size;
+        }
+    }
+
+  /* Make sure we send full copied size */
+  if (progress_callback && last_notified_size != total_size)
+    progress_callback (offset_in, total_size, progress_callback_data);
+
+  return TRUE;
+}
+#endif  /* HAVE_COPY_FILE_RANGE */
+
 #ifdef HAVE_SPLICE
 
 static gboolean
@@ -3042,6 +3163,7 @@ retry:
 
 static gboolean
 splice_stream_with_progress (GInputStream           *in,
+                             GFileInfo              *in_info,
                              GOutputStream          *out,
                              GCancellable           *cancellable,
                              GFileProgressCallback   progress_callback,
@@ -3085,10 +3207,8 @@ splice_stream_with_progress (GInputStream           *in,
   /* avoid performance impact of querying total size when it's not needed */
   if (progress_callback)
     {
-      struct stat sbuf;
-
-      if (fstat (fd_in, &sbuf) == 0)
-        total_size = sbuf.st_size;
+      g_assert (g_file_info_has_attribute (in_info, G_FILE_ATTRIBUTE_STANDARD_SIZE));
+      total_size = g_file_info_get_size (in_info);
     }
 
   if (total_size == -1)
@@ -3151,6 +3271,7 @@ splice_stream_with_progress (GInputStream           *in,
 #ifdef __linux__
 static gboolean
 btrfs_reflink_with_progress (GInputStream           *in,
+                             GFileInfo              *in_info,
                              GOutputStream          *out,
                              GFileInfo              *info,
                              GCancellable           *cancellable,
@@ -3169,10 +3290,8 @@ btrfs_reflink_with_progress (GInputStream           *in,
   /* avoid performance impact of querying total size when it's not needed */
   if (progress_callback)
     {
-      struct stat sbuf;
-
-      if (fstat (fd_in, &sbuf) == 0)
-        total_size = sbuf.st_size;
+      g_assert (g_file_info_has_attribute (in_info, G_FILE_ATTRIBUTE_STANDARD_SIZE));
+      total_size = g_file_info_get_size (in_info);
     }
 
   if (total_size == -1)
@@ -3376,7 +3495,7 @@ file_copy_fallback (GFile                  *source,
     {
       GError *reflink_err = NULL;
 
-      if (!btrfs_reflink_with_progress (in, out, info, cancellable,
+      if (!btrfs_reflink_with_progress (in, info, out, info, cancellable,
                                         progress_callback, progress_callback_data,
                                         &reflink_err))
         {
@@ -3398,12 +3517,36 @@ file_copy_fallback (GFile                  *source,
     }
 #endif
 
+#ifdef HAVE_COPY_FILE_RANGE
+  if (G_IS_FILE_DESCRIPTOR_BASED (in) && G_IS_FILE_DESCRIPTOR_BASED (out))
+    {
+      GError *copy_file_range_error = NULL;
+
+      if (copy_file_range_with_progress (in, info, out, cancellable,
+                                         progress_callback, progress_callback_data,
+                                         &copy_file_range_error))
+        {
+          ret = TRUE;
+          goto out;
+        }
+      else if (!g_error_matches (copy_file_range_error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED))
+        {
+          g_propagate_error (error, g_steal_pointer (&copy_file_range_error));
+          goto out;
+        }
+      else
+        {
+          g_clear_error (&copy_file_range_error);
+        }
+    }
+#endif  /* HAVE_COPY_FILE_RANGE */
+
 #ifdef HAVE_SPLICE
   if (G_IS_FILE_DESCRIPTOR_BASED (in) && G_IS_FILE_DESCRIPTOR_BASED (out))
     {
       GError *splice_err = NULL;
 
-      if (!splice_stream_with_progress (in, out, cancellable,
+      if (!splice_stream_with_progress (in, info, out, cancellable,
                                         progress_callback, progress_callback_data,
                                         &splice_err))
         {
diff --git a/gio/tests/file.c b/gio/tests/file.c
index 754c6c326..7fbb3ef0c 100644
--- a/gio/tests/file.c
+++ b/gio/tests/file.c
@@ -2513,6 +2513,80 @@ test_copy_preserve_mode (void)
 #endif
 }
 
+typedef struct
+{
+  goffset current_num_bytes;
+  goffset total_num_bytes;
+} CopyProgressData;
+
+static void
+file_copy_progress_cb (goffset  current_num_bytes,
+                       goffset  total_num_bytes,
+                       gpointer user_data)
+{
+  CopyProgressData *prev_data = user_data;
+
+  g_assert_cmpuint (total_num_bytes, ==, prev_data->total_num_bytes);
+  g_assert_cmpuint (current_num_bytes, >=, prev_data->current_num_bytes);
+
+  /* Update it for the next callback. */
+  prev_data->current_num_bytes = current_num_bytes;
+}
+
+static void
+test_copy_progress (void)
+{
+  GFile *src_tmpfile = NULL;
+  GFile *dest_tmpfile = NULL;
+  GFileIOStream *iostream;
+  GOutputStream *ostream;
+  GError *local_error = NULL;
+  const guint8 buffer[] = { 1, 2, 3, 4, 5 };
+  CopyProgressData progress_data;
+
+  src_tmpfile = g_file_new_tmp ("tmp-copy-progressXXXXXX",
+                                &iostream, &local_error);
+  g_assert_no_error (local_error);
+
+  /* Write some content to the file for testing. */
+  ostream = g_io_stream_get_output_stream (G_IO_STREAM (iostream));
+  g_output_stream_write (ostream, buffer, sizeof (buffer), NULL, &local_error);
+  g_assert_no_error (local_error);
+
+  g_io_stream_close ((GIOStream *) iostream, NULL, &local_error);
+  g_assert_no_error (local_error);
+  g_clear_object (&iostream);
+
+  /* Grab a unique destination filename. */
+  dest_tmpfile = g_file_new_tmp ("tmp-copy-progressXXXXXX",
+                                 &iostream, &local_error);
+  g_assert_no_error (local_error);
+  g_io_stream_close ((GIOStream *) iostream, NULL, &local_error);
+  g_assert_no_error (local_error);
+  g_clear_object (&iostream);
+
+  /* Set the progress data to an initial offset of zero. The callback will
+   * assert that progress is non-decreasing and reaches the total length of
+   * the file. */
+  progress_data.current_num_bytes = 0;
+  progress_data.total_num_bytes = sizeof (buffer);
+
+  /* Copy the file with progress reporting. */
+  g_file_copy (src_tmpfile, dest_tmpfile, G_FILE_COPY_OVERWRITE,
+               NULL, file_copy_progress_cb, &progress_data, &local_error);
+  g_assert_no_error (local_error);
+
+  g_assert_cmpuint (progress_data.current_num_bytes, ==, progress_data.total_num_bytes);
+  g_assert_cmpuint (progress_data.total_num_bytes, ==, sizeof (buffer));
+
+  /* Clean up. */
+  (void) g_file_delete (src_tmpfile, NULL, NULL);
+  (void) g_file_delete (dest_tmpfile, NULL, NULL);
+
+  g_clear_object (&src_tmpfile);
+  g_clear_object (&dest_tmpfile);
+}
+
 static void
 test_measure (void)
 {
@@ -3844,6 +3918,7 @@ main (int argc, char *argv[])
   g_test_add_func ("/file/async-delete", test_async_delete);
   g_test_add_func ("/file/async-make-symlink", test_async_make_symlink);
   g_test_add_func ("/file/copy-preserve-mode", test_copy_preserve_mode);
+  g_test_add_func ("/file/copy/progress", test_copy_progress);
   g_test_add_func ("/file/measure", test_measure);
   g_test_add_func ("/file/measure-async", test_measure_async);
   g_test_add_func ("/file/load-bytes", test_load_bytes);
@@ -3869,3 +3944,4 @@ main (int argc, char *argv[])
 
   return g_test_run ();
 }
+
diff --git a/meson.build b/meson.build
index 1d75a8be5..44284fc10 100644
--- a/meson.build
+++ b/meson.build
@@ -611,6 +611,7 @@ endif
 functions = [
   'accept4',
   'close_range',
+  'copy_file_range',
   'endmntent',
   'endservent',
   'epoll_create',