# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1628270814 -7200
# Node ID 211abeb2a17edaf97406a5f426334a5e23071291
# Parent  84362bb6f6b93d09943588a4c1aa770eb81b785a
Moved pipe region initialisation into the pipe paging coordinator itself.

diff -r 84362bb6f6b9 -r 211abeb2a17e libfsserver/include/fsserver/pipe_paging.h
--- a/libfsserver/include/fsserver/pipe_paging.h	Fri Aug 06 19:24:56 2021 +0200
+++ b/libfsserver/include/fsserver/pipe_paging.h	Fri Aug 06 19:26:54 2021 +0200
@@ -59,6 +59,10 @@
 
     /* Common functionality. */
 
+    virtual PageMapper *_add_region();
+
+    virtual PageMapper *_next_region();
+
     virtual void discard_region(unsigned int i);
 
 public:
@@ -75,6 +79,8 @@
 
     virtual PageMapper *current_region();
 
+    virtual PageMapper *current_region(bool writing);
+
     virtual PageMapper *next_region();
 
     /* Access management. */
diff -r 84362bb6f6b9 -r 211abeb2a17e libfsserver/lib/pipes/pipe_opener_resource.cc
--- a/libfsserver/lib/pipes/pipe_opener_resource.cc	Fri Aug 06 19:24:56 2021 +0200
+++ b/libfsserver/lib/pipes/pipe_opener_resource.cc	Fri Aug 06 19:26:54 2021 +0200
@@ -84,14 +84,6 @@
 {
     PipePager *pager = new PipePager(paging, writing);
 
-    /* Initialise the first region. */
-
-    offset_t populated_size, region_size;
-    long err = pager->next_region(&populated_size, &region_size);
-
-    if (err)
-        return err;
-
     return ResourceServer(pager).start_thread(endpoint);
 }
 
diff -r 84362bb6f6b9 -r 211abeb2a17e libfsserver/lib/pipes/pipe_pager.cc
--- a/libfsserver/lib/pipes/pipe_pager.cc	Fri Aug 06 19:24:56 2021 +0200
+++ b/libfsserver/lib/pipes/pipe_pager.cc	Fri Aug 06 19:26:54 2021 +0200
@@ -35,6 +35,11 @@
     /* Initialise the size of the paged region. */
 
     _size = _paging->region_size();
+
+    /* Obtain any initial page mapper, this having been set up in the paging
+       coordinator. */
+
+    _mapper = _paging->current_region(_writing);
 }
 
 int PipePager::expected_items()
diff -r 84362bb6f6b9 -r 211abeb2a17e libfsserver/lib/pipes/pipe_paging.cc
--- a/libfsserver/lib/pipes/pipe_paging.cc	Fri Aug 06 19:24:56 2021 +0200
+++ b/libfsserver/lib/pipes/pipe_paging.cc	Fri Aug 06 19:26:54 2021 +0200
@@ -41,6 +41,11 @@
 
     for (unsigned int i = 0; i < 2; i++)
         _regions[i] = NULL;
+
+    /* Initialise a region accessible by reader and writer. */
+
+    _add_region();
+    _next_region();
 }
 
 /* Return whether one or more endpoints have detached. */
@@ -94,7 +99,7 @@
 
 /* Add a region to the sequence. */
 
-PageMapper *PipePaging::add_region()
+PageMapper *PipePaging::_add_region()
 {
     /* If the writer already accesses a different region to the reader, no new
        region is added. */
@@ -117,6 +122,15 @@
 
     _regions[_writing] = mapper;
 
+    /* Return the next region's mapper. */
+
+    return mapper;
+}
+
+PageMapper *PipePaging::add_region()
+{
+    PageMapper *mapper = _add_region();
+
     /* Let the writer notify the reader. */
 
     notify_others(PipePaging::WRITER, NOTIFY_CONTENT_AVAILABLE);
@@ -133,12 +147,19 @@
     return _regions[_reading];
 }
 
+/* Return the current region for reading or writing. */
+
+PageMapper *PipePaging::current_region(bool writing)
+{
+    return _regions[writing ? _writing : _reading];
+}
+
 /* Return the next region for the reader if the writer is using a different one.
    Otherwise, return NULL. */
 
-PageMapper *PipePaging::next_region()
+PageMapper *PipePaging::_next_region()
 {
-    /* If the reader already accesses the same region to the writer, no next
+    /* If the reader already accesses the same region as the writer, no next
        region can be obtained. */
 
     if (_reading == _writing)
@@ -152,13 +173,20 @@
 
     _reading = 1 - _reading;
 
-    /* Let the reader notify the writer. */
-
-    notify_others(PipePaging::READER, NOTIFY_SPACE_AVAILABLE);
-
     /* Return the next region's mapper. */
 
     return _regions[_reading];
 }
 
+PageMapper *PipePaging::next_region()
+{
+    PageMapper *mapper = _next_region();
+
+    /* Let the reader notify the writer. */
+
+    notify_others(PipePaging::READER, NOTIFY_SPACE_AVAILABLE);
+
+    return mapper;
+}
+
 // vim: tabstop=4 expandtab shiftwidth=4