Libguestfs - Jul 2014 - Re: [PATCH] generator: Sort the structs.

Sort the structs when generating code.  Since the structs are
logically indepedent of each other, this should have no effect except
to make generated files list the structs in a different order.

However this also fixes the following build problem:

  File "convert_linux.ml", line 322, characters 43-50:
  Error: This expression has type G.stat = Guestfs.stat
    but an expression was expected of type G.dirent = Guestfs.dirent

It turns out the OCaml bindings don't like the fact that we have
two structs with a common field name (dirent.ino and stat.ino).

In OCaml < 4.01, this means that any attempt to reference stat.ino
would fail because dirent.ino appears second in the file, overriding
stat.ino.

In OCaml >= 4.01 the compiler now uses some disambiguation rules based
on the known types to resolve this problem.

See:

http://ocaml.org/releases/4.01.0.html
http://www.lexifi.com/blog/type-based-selection-label-and-constructors
http://www.lexifi.com/blog/ocaml-extensions-lexifi-overidding-record-labels-and-constructors
---
 generator/structs.ml |  8 ++++++--
 gobject/Makefile.inc | 48 ++++++++++++++++++++++++------------------------
 2 files changed, 30 insertions(+), 26 deletions(-)

diff --git a/generator/structs.ml b/generator/structs.ml
index 1bc6e08..65c78b2 100644
--- a/generator/structs.ml
+++ b/generator/structs.ml
@@ -382,6 +382,10 @@ let camel_name_of_struct name = (lookup_struct
name).s_camel_name
 
 let cols_of_struct name = (lookup_struct name).s_cols
 
-let external_structs = List.filter (fun x -> not x.s_internal) structs
+let compare_structs { s_name = n1 } { s_name = n2 } = compare n1 n2
 
-let internal_structs = List.filter (fun x -> x.s_internal) structs
+let external_structs +  List.sort compare_structs (List.filter (fun x -> not
x.s_internal) structs)
+
+let internal_structs +  List.sort compare_structs (List.filter (fun x ->
x.s_internal) structs)
diff --git a/gobject/Makefile.inc b/gobject/Makefile.inc
index 3b567a2..ed1ff3b 100644
--- a/gobject/Makefile.inc
+++ b/gobject/Makefile.inc
@@ -23,26 +23,26 @@ guestfs_gobject_headers= \
   include/guestfs-gobject.h \
   include/guestfs-gobject/session.h \
   include/guestfs-gobject/tristate.h \
+  include/guestfs-gobject/struct-application.h \
+  include/guestfs-gobject/struct-application2.h \
+  include/guestfs-gobject/struct-btrfssubvolume.h \
+  include/guestfs-gobject/struct-dirent.h \
+  include/guestfs-gobject/struct-hivex_node.h \
+  include/guestfs-gobject/struct-hivex_value.h \
+  include/guestfs-gobject/struct-inotify_event.h \
   include/guestfs-gobject/struct-int_bool.h \
+  include/guestfs-gobject/struct-isoinfo.h \
+  include/guestfs-gobject/struct-lvm_lv.h \
   include/guestfs-gobject/struct-lvm_pv.h \
   include/guestfs-gobject/struct-lvm_vg.h \
-  include/guestfs-gobject/struct-lvm_lv.h \
+  include/guestfs-gobject/struct-mdstat.h \
+  include/guestfs-gobject/struct-partition.h \
   include/guestfs-gobject/struct-stat.h \
   include/guestfs-gobject/struct-statvfs.h \
-  include/guestfs-gobject/struct-dirent.h \
+  include/guestfs-gobject/struct-utsname.h \
   include/guestfs-gobject/struct-version.h \
   include/guestfs-gobject/struct-xattr.h \
-  include/guestfs-gobject/struct-inotify_event.h \
-  include/guestfs-gobject/struct-partition.h \
-  include/guestfs-gobject/struct-application.h \
-  include/guestfs-gobject/struct-application2.h \
-  include/guestfs-gobject/struct-isoinfo.h \
-  include/guestfs-gobject/struct-mdstat.h \
-  include/guestfs-gobject/struct-btrfssubvolume.h \
   include/guestfs-gobject/struct-xfsinfo.h \
-  include/guestfs-gobject/struct-utsname.h \
-  include/guestfs-gobject/struct-hivex_node.h \
-  include/guestfs-gobject/struct-hivex_value.h \
   include/guestfs-gobject/optargs-add_domain.h \
   include/guestfs-gobject/optargs-add_drive.h \
   include/guestfs-gobject/optargs-add_drive_scratch.h \
@@ -100,26 +100,26 @@ guestfs_gobject_headers= \
 guestfs_gobject_sources= \
   src/session.c \
   src/tristate.c \
+  src/struct-application.c \
+  src/struct-application2.c \
+  src/struct-btrfssubvolume.c \
+  src/struct-dirent.c \
+  src/struct-hivex_node.c \
+  src/struct-hivex_value.c \
+  src/struct-inotify_event.c \
   src/struct-int_bool.c \
+  src/struct-isoinfo.c \
+  src/struct-lvm_lv.c \
   src/struct-lvm_pv.c \
   src/struct-lvm_vg.c \
-  src/struct-lvm_lv.c \
+  src/struct-mdstat.c \
+  src/struct-partition.c \
   src/struct-stat.c \
   src/struct-statvfs.c \
-  src/struct-dirent.c \
+  src/struct-utsname.c \
   src/struct-version.c \
   src/struct-xattr.c \
-  src/struct-inotify_event.c \
-  src/struct-partition.c \
-  src/struct-application.c \
-  src/struct-application2.c \
-  src/struct-isoinfo.c \
-  src/struct-mdstat.c \
-  src/struct-btrfssubvolume.c \
   src/struct-xfsinfo.c \
-  src/struct-utsname.c \
-  src/struct-hivex_node.c \
-  src/struct-hivex_value.c \
   src/optargs-add_domain.c \
   src/optargs-add_drive.c \
   src/optargs-add_drive_scratch.c \
-- 
1.9.0

On Tuesday 01 July 2014 16:16:18 Richard W.M. Jones
wrote:
> Sort the structs when generating code.  Since the structs are
> logically indepedent of each other, this should have no effect except
> to make generated files list the structs in a different order.
> 
> However this also fixes the following build problem:
> 
>   File "convert_linux.ml", line 322, characters 43-50:
>   Error: This expression has type G.stat = Guestfs.stat
>     but an expression was expected of type G.dirent = Guestfs.dirent
> 
> It turns out the OCaml bindings don't like the fact that we have
> two structs with a common field name (dirent.ino and stat.ino).
> 
> In OCaml < 4.01, this means that any attempt to reference stat.ino
> would fail because dirent.ino appears second in the file, overriding
> stat.ino.
So that means that with such OCaml versions both the .ino members cannot 
be used at the same time?
> In OCaml >= 4.01 the compiler now uses some disambiguation rules based
> on the known types to resolve this problem.
Patch seems good to me.

Thanks,
-- 
Pino Toscano

On Tue, Jul 01, 2014 at 05:27:42PM +0200, Pino Toscano
wrote:
> On Tuesday 01 July 2014 16:16:18 Richard W.M. Jones wrote:
> > Sort the structs when generating code.  Since the structs are
> > logically indepedent of each other, this should have no effect except
> > to make generated files list the structs in a different order.
> > 
> > However this also fixes the following build problem:
> > 
> >   File "convert_linux.ml", line 322, characters 43-50:
> >   Error: This expression has type G.stat = Guestfs.stat
> >     but an expression was expected of type G.dirent = Guestfs.dirent
> > 
> > It turns out the OCaml bindings don't like the fact that we have
> > two structs with a common field name (dirent.ino and stat.ino).
> > 
> > In OCaml < 4.01, this means that any attempt to reference stat.ino
> > would fail because dirent.ino appears second in the file, overriding
> > stat.ino.
> 
> So that means that with such OCaml versions both the .ino members cannot 
> be used at the same time?
Yup.  Luckily we don't use `dirent.ino'.
> > In OCaml >= 4.01 the compiler now uses some disambiguation rules
based
> > on the known types to resolve this problem.
> 
> Patch seems good to me.
Thanks - I will push it in a moment.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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