BCCSP Factory support

This change-set introduces support for multiple BCCSP factories.
This way, it will be possible to have software-based as well as
hardware-based BCCSP implementations.
The fatory provides also access to a default BCCSP that represents the BCCSP
to be used by default as it is configured via viper.
Tests have been added to test the factories.
This change-set comes in the context of:
https://jira.hyperledger.org/browse/FAB-354

Change-Id: Ib83f1fc31fa0ac77daa76f97684563e4c6e53877
Signed-off-by: Angelo De Caro <adc@zurich.ibm.com>

core/crypto/bccsp/factory/factory.go

@@ -0,0 +1,127 @@
+/*
+Copyright IBM Corp. 2016 All Rights Reserved.
+
+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 factory
+
+import (
+	"errors"
+	"fmt"
+	"sync"
+
+	"github.com/hyperledger/fabric/core/crypto/bccsp"
+	"github.com/spf13/viper"
+)
+
+var (
+	// Default BCCSP
+	defaultBCCSP bccsp.BCCSP
+
+	// BCCSP Factories
+	factories map[string]BCCSPFactory
+
+	// factories' Sync on Initialization
+	factoriesInitOnce sync.Once
+
+	// Factories' Initialization Error
+	factoriesInitError error
+)
+
+// BCCSPFactory is used to get instances of the BCCSP interface.
+// A Factory has name used to address it.
+type BCCSPFactory interface {
+
+	// Name returns the name of this factory
+	Name() string
+
+	// Get returns an instance of BCCSP using opts.
+	Get(opts Opts) (bccsp.BCCSP, error)
+}
+
+// Opts  contains options for instantiating BCCSPs.
+type Opts interface {
+
+	// FactoryName returns the name of the factory to be used
+	FactoryName() string
+
+	// Ephemeral returns true if the BCCSP has to be ephemeral, false otherwise
+	Ephemeral() bool
+}
+
+// GetDefault returns a non-ephemeral (long-term) BCCSP
+func GetDefault() (bccsp.BCCSP, error) {
+	if err := initFactories(); err != nil {
+		return nil, err
+	}
+
+	return defaultBCCSP, nil
+}
+
+// GetBCCSP returns a BCCSP created according to the options passed in input.
+func GetBCCSP(opts Opts) (bccsp.BCCSP, error) {
+	if err := initFactories(); err != nil {
+		return nil, err
+	}
+
+	return getBCCSPInternal(opts)
+}
+
+func initFactories() error {
+	factoriesInitOnce.Do(func() {
+		// Initialize factories map
+		if factoriesInitError = initFactoriesMap(); factoriesInitError != nil {
+			return
+		}
+
+		// Create default non-ephemeral (long-term) BCCSP
+		defaultBCCSP, factoriesInitError = createDefaultBCCSP()
+		if factoriesInitError != nil {
+			return
+		}
+	})
+	return factoriesInitError
+}
+
+func initFactoriesMap() error {
+	factories = make(map[string]BCCSPFactory)
+
+	// Software-Based BCCSP
+	f := &SWFactory{}
+	factories[f.Name()] = f
+
+	return nil
+}
+
+func createDefaultBCCSP() (bccsp.BCCSP, error) {
+	defaultBCCSPFactoryName := viper.GetString("bccsp.default")
+	if defaultBCCSPFactoryName == "" {
+		defaultBCCSPFactoryName = SoftwareBasedFactoryName
+	}
+
+	return getBCCSPInternal(&DefaultOpts{defaultBCCSPFactoryName, false})
+}
+
+func getBCCSPInternal(opts Opts) (bccsp.BCCSP, error) {
+	// Validate arguments
+	if opts == nil {
+		return nil, errors.New("Cannot instantiate a factory with 'nil' Opts. A fully instantiated BCCSP Opts struct must be provided.")
+	}
+
+	f, ok := factories[opts.FactoryName()]
+	if ok {
+		return f.Get(opts)
+	}
+
+	return nil, fmt.Errorf("Factory [%s] does not exist.", opts.FactoryName())
+}

core/crypto/bccsp/factory/factory_opts.go

@@ -0,0 +1,32 @@
+/*
+Copyright IBM Corp. 2016 All Rights Reserved.
+
+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 factory
+
+// DefaultOpts offers a default implementation for Opts
+type DefaultOpts struct {
+	ProviderName  string
+	EphemeralFlag bool
+}
+
+// FactoryName returns the name of the provider
+func (o *DefaultOpts) FactoryName() string {
+	return o.ProviderName
+}
+
+// Ephemeral returns true if the CSP has to be ephemeral, false otherwise
+func (o *DefaultOpts) Ephemeral() bool {
+	return o.EphemeralFlag
+}

core/crypto/bccsp/factory/factory_test.go

@@ -0,0 +1,60 @@
+/*
+Copyright IBM Corp. 2016 All Rights Reserved.
+
+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 factory
+
+import "testing"
+
+func TestGetDefault(t *testing.T) {
+	bccsp, err := GetDefault()
+	if err != nil {
+		t.Fatalf("Failed getting default BCCSP [%s]", err)
+	}
+	if bccsp == nil {
+		t.Fatal("Failed getting default BCCSP. Nil instance.")
+	}
+}
+
+func TestGetBCCPEphemeral(t *testing.T) {
+	bccsp1, err := GetBCCSP(&SwOpts{EphemeralFlag: true})
+	if err != nil {
+		t.Fatalf("Failed getting ephemeral software-based BCCSP [%s]", err)
+	}
+
+	bccsp2, err := GetBCCSP(&SwOpts{EphemeralFlag: true})
+	if err != nil {
+		t.Fatalf("Failed getting ephemeral software-based BCCSP [%s]", err)
+	}
+
+	if bccsp1 == bccsp2 {
+		t.Fatal("Ephemeral BCCSPs should point to different instances")
+	}
+}
+
+func TestGetBCCP2Ephemeral(t *testing.T) {
+	bccsp1, err := GetBCCSP(&SwOpts{EphemeralFlag: false})
+	if err != nil {
+		t.Fatalf("Failed getting non-ephemeral software-based BCCSP [%s]", err)
+	}
+
+	bccsp2, err := GetBCCSP(&SwOpts{EphemeralFlag: false})
+	if err != nil {
+		t.Fatalf("Failed getting non-ephemeral software-based BCCSP [%s]", err)
+	}
+
+	if bccsp1 != bccsp2 {
+		t.Fatal("Non-ephemeral BCCSPs should point to the same instance")
+	}
+}

core/crypto/bccsp/factory/sw_factory.go

@@ -0,0 +1,79 @@
+/*
+Copyright IBM Corp. 2016 All Rights Reserved.
+
+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 factory
+
+import (
+	"errors"
+	"fmt"
+	"sync"
+
+	"github.com/hyperledger/fabric/core/crypto/bccsp"
+	"github.com/hyperledger/fabric/core/crypto/bccsp/sw"
+)
+
+const (
+	// SoftwareBasedFactoryName is the name of the factory of the software-based BCCSP implementation
+	SoftwareBasedFactoryName = "SW"
+)
+
+// SWFactory is the factory of the software-based BCCSP.
+type SWFactory struct {
+	initOnce sync.Once
+	bccsp    bccsp.BCCSP
+	err      error
+}
+
+// Name returns the name of this factory
+func (f *SWFactory) Name() string {
+	return SoftwareBasedFactoryName
+}
+
+// Get returns an instance of BCCSP using Opts.
+func (f *SWFactory) Get(opts Opts) (bccsp.BCCSP, error) {
+	// Validate arguments
+	if opts == nil {
+		return nil, errors.New("Invalid opts. It must not be nil.")
+	}
+
+	if opts.FactoryName() != f.Name() {
+		return nil, fmt.Errorf("Invalid Provider Name [%s]. Opts must refer to [%s].", opts.FactoryName(), f.Name())
+	}
+
+	if !opts.Ephemeral() {
+		f.initOnce.Do(func() {
+			f.bccsp, f.err = sw.New()
+			return
+		})
+		return f.bccsp, f.err
+	}
+
+	return sw.New()
+}
+
+// SwOpts contains options for the SWFactory
+type SwOpts struct {
+	EphemeralFlag bool
+}
+
+// FactoryName returns the name of the provider
+func (o *SwOpts) FactoryName() string {
+	return SoftwareBasedFactoryName
+}
+
+// Ephemeral returns true if the CSP has to be ephemeral, false otherwise
+func (o *SwOpts) Ephemeral() bool {
+	return o.EphemeralFlag
+}