util: convenience utilities for fscrypt

This commit adds in the util package. This package provides
two functions for creating errors. These functions are:
	- InvalidInputErrorF - bad input from user or caller
	- SystemErrorF - low level failure

It also adds in a small function for converting Go byte slices into C
void pointers. This will be very useful for interoperating with C.

Change-Id: I87ad7946dd5fa26e28927590aff4bcc9fd5ce4f7

1 files changed, 60 insertions, 0 deletions

diff --git a/util/util_test.go b/util/util_test.go
new file mode 100644
index 0000000..65541b3
--- /dev/null
+++ b/util/util_test.go
@@ -0,0 +1,60 @@
+/*
+ * util_test.go - Tests the util package
+ *
+ * Copyright 2017 Google Inc.
+ * Author: Joe Richey (joerichey@google.com)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package util
+
+import (
+	"testing"
+)
+
+const offset = 3
+
+// Make sure the address behaves well under slicing
+func TestPtrOffset(t *testing.T) {
+	arr := []byte{'a', 'b', 'c', 'd'}
+	i1 := uintptr(Ptr(arr[offset:]))
+	i2 := uintptr(Ptr(arr))
+
+	if i1 != i2+offset {
+		t.Fatalf("pointers %v and %v do not have an offset of %v", i1, i2, offset)
+	}
+}
+
+// Make sure NeverError actually panics
+func TestNeverErrorPanic(t *testing.T) {
+	defer func() {
+		if r := recover(); r == nil {
+			t.Errorf("NeverError did not panic")
+		}
+	}()
+
+	err := SystemErrorF("Hello")
+	NeverError(err)
+}
+
+// Make sure NeverError doesn't panic on nil
+func TestNeverErrorNoPanic(t *testing.T) {
+	defer func() {
+		if r := recover(); r != nil {
+			t.Errorf("NeverError panicked")
+		}
+	}()
+
+	NeverError(nil)
+}