From 9ea34e9c8f4459ea477128ec8d62af91973406be Mon Sep 17 00:00:00 2001
From: Ethan Frey <ethanfrey@users.noreply.github.com>
Date: Wed, 12 Jul 2017 16:53:07 +0200
Subject: [PATCH] Add CheckHandler as a helper

---
 stack/helpers.go      | 60 ++++++++++++++++++++++++++++++++++++++++---
 stack/helpers_test.go | 35 +++++++++++++++++++++++++
 stack/helperware.go   |  4 +--
 3 files changed, 94 insertions(+), 5 deletions(-)

diff --git a/stack/helpers.go b/stack/helpers.go
index a3dd296e5f..a21c867fa3 100644
--- a/stack/helpers.go
+++ b/stack/helpers.go
@@ -18,14 +18,19 @@ const (
 
 //nolint
 const (
-	ByteRawTx  = 0x1
-	TypeRawTx  = "raw"
+	ByteRawTx   = 0xF0
+	ByteCheckTx = 0xF1
+
+	TypeRawTx   = "raw"
+	TypeCheckTx = NameCheck + "/tx"
+
 	rawMaxSize = 2000 * 1000
 )
 
 func init() {
 	basecoin.TxMapper.
-		RegisterImplementation(RawTx{}, TypeRawTx, ByteRawTx)
+		RegisterImplementation(RawTx{}, TypeRawTx, ByteRawTx).
+		RegisterImplementation(CheckTx{}, TypeCheckTx, ByteCheckTx)
 }
 
 // RawTx just contains bytes that can be hex-ified
@@ -49,6 +54,24 @@ func (r RawTx) ValidateBasic() error {
 	return nil
 }
 
+// CheckTx contains a list of permissions to be tested
+type CheckTx struct {
+	Required []basecoin.Actor
+}
+
+var _ basecoin.TxInner = CheckTx{}
+
+// nolint
+func NewCheckTx(req []basecoin.Actor) basecoin.Tx {
+	return CheckTx{req}.Wrap()
+}
+func (c CheckTx) Wrap() basecoin.Tx {
+	return basecoin.Tx{c}
+}
+func (CheckTx) ValidateBasic() error {
+	return nil
+}
+
 // OKHandler just used to return okay to everything
 type OKHandler struct {
 	Log string
@@ -148,3 +171,34 @@ func (p PanicHandler) DeliverTx(ctx basecoin.Context, store state.KVStore, tx ba
 	}
 	panic(p.Msg)
 }
+
+// CheckHandler accepts CheckTx and verifies the permissions
+type CheckHandler struct {
+	PassOption
+}
+
+// Name - return handler's name
+func (CheckHandler) Name() string {
+	return NameCheck
+}
+
+// CheckTx verifies the permissions
+func (c CheckHandler) CheckTx(ctx basecoin.Context, store state.KVStore, tx basecoin.Tx) (res basecoin.Result, err error) {
+	check, ok := tx.Unwrap().(CheckTx)
+	if !ok {
+		return res, errors.ErrUnknownTxType(tx)
+	}
+
+	for _, perm := range check.Required {
+		if !ctx.HasPermission(perm) {
+			return res, errors.ErrUnauthorized()
+		}
+	}
+	return res, nil
+}
+
+// DeliverTx verifies the permissions
+func (c CheckHandler) DeliverTx(ctx basecoin.Context, store state.KVStore, tx basecoin.Tx) (res basecoin.Result, err error) {
+	// until something changes, just do the same as check
+	return c.CheckTx(ctx, store, tx)
+}
diff --git a/stack/helpers_test.go b/stack/helpers_test.go
index 58748e054d..a45732c16b 100644
--- a/stack/helpers_test.go
+++ b/stack/helpers_test.go
@@ -62,3 +62,38 @@ func TestPanic(t *testing.T) {
 	assert.Panics(func() { fail.CheckTx(ctx, store, tx) })
 	assert.Panics(func() { fail.DeliverTx(ctx, store, tx) })
 }
+
+func TestCheck(t *testing.T) {
+	assert := assert.New(t)
+
+	ctx := MockContext("check-chain", 123)
+	store := state.NewMemKVStore()
+	h := CheckHandler{}
+
+	a := basecoin.Actor{App: "foo", Address: []byte("baz")}
+	b := basecoin.Actor{App: "si-ly", Address: []byte("bar")}
+
+	cases := []struct {
+		valid             bool
+		signers, required []basecoin.Actor
+	}{
+		{true, []basecoin.Actor{a}, []basecoin.Actor{a}},
+		{true, []basecoin.Actor{a, b}, []basecoin.Actor{a}},
+		{false, []basecoin.Actor{a}, []basecoin.Actor{a, b}},
+		{false, []basecoin.Actor{a}, []basecoin.Actor{b}},
+	}
+
+	for i, tc := range cases {
+		tx := CheckTx{tc.required}.Wrap()
+		myCtx := ctx.WithPermissions(tc.signers...)
+		_, err := h.CheckTx(myCtx, store, tx)
+		_, err2 := h.DeliverTx(myCtx, store, tx)
+		if tc.valid {
+			assert.Nil(err, "%d: %+v", i, err)
+			assert.Nil(err2, "%d: %+v", i, err2)
+		} else {
+			assert.NotNil(err, "%d", i)
+			assert.NotNil(err2, "%d", i)
+		}
+	}
+}
diff --git a/stack/helperware.go b/stack/helperware.go
index adca481c6d..46cdfaa8cc 100644
--- a/stack/helperware.go
+++ b/stack/helperware.go
@@ -8,8 +8,8 @@ import (
 )
 
 const (
-	NameCheck = "chck"
-	NameGrant = "grnt"
+	NameCheck = "check"
+	NameGrant = "grant"
 )
 
 // CheckMiddleware returns an error if the tx doesn't have auth of this