[FAB-6071] Add application capabilities structures

Certain capabilities may be required of the peer which are completely
irrelevant to the other pieces of the system (such as the orderer).  For
instance, whether a peer may process side-DB transactions had no impact
on the orderer, because the orderer is left out of these transactions by
design.

This CR adds basic support for application/peer capabilities though none
are currently implemented.

Change-Id: I27fe1266b370b6d71791c5782bbe641c081e8f62
Signed-off-by: Jason Yellick <jyellick@us.ibm.com>

common/capabilities/application.go

@@ -0,0 +1,41 @@
+/*
+Copyright IBM Corp. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package capabilities
+
+import (
+	cb "github.com/hyperledger/fabric/protos/common"
+)
+
+const (
+	applicationTypeName = "Application"
+)
+
+// ApplicationProvider provides capabilities information for application level config.
+type ApplicationProvider struct {
+	*registry
+}
+
+// NewApplicationProvider creates a application capabilities provider.
+func NewApplicationProvider(capabilities map[string]*cb.Capability) *ApplicationProvider {
+	cp := &ApplicationProvider{}
+	cp.registry = newRegistry(cp, capabilities)
+	return cp
+}
+
+// Type returns a descriptive string for logging purposes.
+func (cp *ApplicationProvider) Type() string {
+	return applicationTypeName
+}
+
+// HasCapability returns true if the capability is supported by this binary.
+func (cp *ApplicationProvider) HasCapability(capability string) bool {
+	switch capability {
+	// Add new capability names here
+	default:
+		return false
+	}
+}

common/capabilities/capabilities_test.go

@@ -25,6 +25,7 @@ func TestSatisfied(t *testing.T) {
 		for _, provider := range []*registry{
 			NewChannelProvider(capsMap).registry,
 			NewOrdererProvider(capsMap).registry,
+			NewApplicationProvider(capsMap).registry,
 		} {
 			assert.Nil(t, provider.Supported())
 		}
@@ -42,6 +43,7 @@ func TestSatisfied(t *testing.T) {
 		for _, provider := range []*registry{
 			NewChannelProvider(capsMap).registry,
 			NewOrdererProvider(capsMap).registry,
+			NewApplicationProvider(capsMap).registry,
 		} {
 			assert.Nil(t, provider.Supported())
 		}
@@ -57,6 +59,7 @@ func TestNotSatisfied(t *testing.T) {
 	for _, provider := range []*registry{
 		NewChannelProvider(capsMap).registry,
 		NewOrdererProvider(capsMap).registry,
+		NewApplicationProvider(capsMap).registry,
 	} {
 		assert.Error(t, provider.Supported())
 	}