[PATCH 17/28] libxl: ocaml: add with_ctx helper function

[Rob Hoes <rob.hoes@citrix.com>]

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>
---
 tools/ocaml/libs/xl/xenlight.ml.in  |   15 +++++++++++++++
 tools/ocaml/libs/xl/xenlight.mli.in |    4 +++-
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/tools/ocaml/libs/xl/xenlight.ml.in b/tools/ocaml/libs/xl/xenlight.ml.in
index 3e83355..991b2bf 100644
--- a/tools/ocaml/libs/xl/xenlight.ml.in
+++ b/tools/ocaml/libs/xl/xenlight.ml.in
@@ -53,6 +53,21 @@ type ctx
 external ctx_alloc: Xentoollog.handle -> ctx = "stub_libxl_ctx_alloc"
 external ctx_free: ctx -> unit = "stub_libxl_ctx_free"
 
+let with_ctx ?logger f =
+	let logger' = match logger with
+		| None -> Xentoollog.create_stdio_logger (*~level:Xentoollog.Debug*) ()
+		| Some l -> l
+	in
+	let ctx = ctx_alloc logger' in
+	let res = try f ctx with exn ->
+		ctx_free ctx;
+		if logger = None then Xentoollog.destroy logger';
+		raise exn
+	in
+	ctx_free ctx;
+	if logger = None then Xentoollog.destroy logger';
+	res
+
 external test_raise_exception: unit -> unit = "stub_raise_exception"
 
 type domid = int
diff --git a/tools/ocaml/libs/xl/xenlight.mli.in b/tools/ocaml/libs/xl/xenlight.mli.in
index e562c4b..12568ca 100644
--- a/tools/ocaml/libs/xl/xenlight.mli.in
+++ b/tools/ocaml/libs/xl/xenlight.mli.in
@@ -38,7 +38,9 @@ type ctx
 external ctx_alloc: Xentoollog.handle -> ctx = "stub_libxl_ctx_alloc"
 external ctx_free: ctx -> unit = "stub_libxl_ctx_free"
 
-external test_raise_exception: unit = "stub_raise_exception"
+val with_ctx : ?logger:Xentoollog.handle -> (ctx -> 'a) -> 'a
+
+external test_raise_exception: unit -> unit = "stub_raise_exception"
 
 type domid = int
 type devid = int
-- 
1.7.10.4