# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1620166151 -7200
# Node ID 13859678adc286f0dc46ed04c2c66cad415cb318
# Parent  6e84d8639c638ba2579a810d64f1e546aa6413c7
Somewhat reorganised and also renamed the internal flush/access function.

diff -r 6e84d8639c63 -r 13859678adc2 libfsclient/lib/src/client.cc
--- a/libfsclient/lib/src/client.cc	Tue May 04 00:19:19 2021 +0200
+++ b/libfsclient/lib/src/client.cc	Wed May 05 00:09:11 2021 +0200
@@ -108,42 +108,51 @@
 
 
 
-/* Flush data conditionally to the filesystem object. */
+/* Access the given position and synchronise state with the file object. */
 
-static long _flush(file_t *file, offset_t position)
+static long _access(file_t *file, offset_t position)
 {
   long err;
 
-  /* Where the position is outside the current region, re-map. */
+  if (file->can_mmap)
+  {
+    /* Where the position is outside the current region, re-map. */
 
-  if ((position < file->start_pos) || (position >= file->end_pos))
-  {
-    if (file->can_mmap)
+    if ((position < file->start_pos) || (position >= file->end_pos))
     {
       if (file_mmap(file, position, file_span(file)))
         return -L4_EIO;
     }
 
-    /* Strict conditions for region navigation in pipes. */
+    /* Otherwise, flush any written data in the current region and update the
+       file size details. */
 
     else
     {
-      if ((position != file->end_pos) || (client_next_region(file) == NULL))
-        return -L4_EIO;
-    }
-  }
-
-  /* Otherwise, flush any written data in the current region and update the
-     file size details. */
-
-  else
-  {
-    if (file->can_mmap)
-    {
       err = client_flush(file);
       if (err)
         return err;
     }
+  }
+  else
+  {
+    /* Strict conditions for region navigation in pipes. */
+
+    if ((position < file->start_pos) || (position > file->end_pos))
+    {
+      return -L4_EIO;
+    }
+
+    /* The next region is only available at the end of the mapped memory. */
+
+    else if (position == file->end_pos)
+    {
+      if (client_next_region(file) == NULL)
+        return -L4_EIO;
+    }
+
+    /* Within the current pipe region, synchronise with the pipe object. */
+
     else
     {
       if (client_current_region(file) == NULL)
@@ -257,7 +266,7 @@
       /* Flush any unwritten data, preparing to read from the file position at
          the end of the data, and returning if no new data is available. */
 
-      if (_flush(file, file_data_end_position(file)))
+      if (_access(file, file_data_end_position(file)))
         break;
 
       available = file_data_available(file);
@@ -354,7 +363,7 @@
 
   /* Handle unwritten data and reset the buffer for reading. */
 
-  _flush(file, position);
+  _access(file, position);
   return position;
 }
 
@@ -413,7 +422,7 @@
       /* Flush any unwritten data and continue writing from the current data
          position. */
 
-      if (_flush(file, file_data_current_position(file)))
+      if (_access(file, file_data_current_position(file)))
         break;
 
       space = file_data_space(file);