ndr: avoid unnecessary searches of token list

When pulling complex structures like nt-acls, a long list of tokens
may be produced. This change means the token list won't be walked in the
buffers case if the switch value is not needed.

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>

1 files changed, 35 insertions, 14 deletions

diff --git a/pidl/lib/Parse/Pidl/Samba4/NDR/Parser.pm b/pidl/lib/Parse/Pidl/Samba4/NDR/Parser.pm
index f52d4b10f6d..c53ec4a8690 100644
--- a/pidl/lib/Parse/Pidl/Samba4/NDR/Parser.pm
+++ b/pidl/lib/Parse/Pidl/Samba4/NDR/Parser.pm
@@ -321,6 +321,25 @@ sub check_null_pointer($$$$)
 	}
 }
 
+sub is_deferred_switch_non_empty($)
+{
+	# 1 if there needs to be a deferred branch in an ndr_pull/push,
+	# 0 otherwise.
+	my ($e) = @_;
+	my $have_default = 0;
+	foreach my $el (@{$e->{ELEMENTS}}) {
+		if ($el->{CASE} eq "default") {
+			$have_default = 1;
+		}
+		if ($el->{TYPE} ne "EMPTY") {
+			if (ContainsDeferred($el, $el->{LEVELS}[0])) {
+				return 1;
+			}
+		}
+	}
+	return ! $have_default;
+}
+
 sub ParseArrayPullGetSize($$$$$$)
 {
 	my ($self,$e,$l,$ndr,$var_name,$env) = @_;
@@ -1923,11 +1942,13 @@ sub ParseUnionPush($$$$)
 	$self->ParseUnionPushPrimitives($e, $ndr, $varname);
 	$self->deindent;
 	$self->pidl("}");
-	$self->pidl("if (ndr_flags & NDR_BUFFERS) {");
-	$self->indent;
-	$self->ParseUnionPushDeferred($e, $ndr, $varname);
-	$self->deindent;
-	$self->pidl("}");
+        if (is_deferred_switch_non_empty($e)) {
+                $self->pidl("if (ndr_flags & NDR_BUFFERS) {");
+                $self->indent;
+                $self->ParseUnionPushDeferred($e, $ndr, $varname);
+                $self->deindent;
+                $self->pidl("}");
+        }
 	$self->end_flags($e, $ndr);
 }
 
@@ -2093,21 +2114,21 @@ sub ParseUnionPull($$$$)
 
 	$self->start_flags($e, $ndr);
 
-	$self->pidl("level = ndr_pull_get_switch_value($ndr, $varname);");
-
 	$self->pidl("NDR_PULL_CHECK_FLAGS(ndr, ndr_flags);");
 	$self->pidl("if (ndr_flags & NDR_SCALARS) {");
 	$self->indent;
+        $self->pidl("level = ndr_pull_get_switch_value($ndr, $varname);");
 	$self->ParseUnionPullPrimitives($e,$ndr,$varname,$switch_type);
 	$self->deindent;
 	$self->pidl("}");
-
-	$self->pidl("if (ndr_flags & NDR_BUFFERS) {");
-	$self->indent;
-	$self->ParseUnionPullDeferred($e,$ndr,$varname);
-	$self->deindent;
-	$self->pidl("}");
-
+        if (is_deferred_switch_non_empty($e)) {
+                $self->pidl("if (ndr_flags & NDR_BUFFERS) {");
+                $self->indent;
+                $self->pidl("level = ndr_pull_get_switch_value($ndr, $varname);");
+                $self->ParseUnionPullDeferred($e,$ndr,$varname);
+                $self->deindent;
+                $self->pidl("}");
+        }
 	$self->add_deferred();
 
 	$self->end_flags($e, $ndr);