257 lines
7.3 KiB
Go
257 lines
7.3 KiB
Go
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// Copyright 2016 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package iam supports the resource-specific operations of Google Cloud
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// IAM (Identity and Access Management) for the Google Cloud Libraries.
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// See https://cloud.google.com/iam for more about IAM.
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//
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// Users of the Google Cloud Libraries will typically not use this package
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// directly. Instead they will begin with some resource that supports IAM, like
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// a pubsub topic, and call its IAM method to get a Handle for that resource.
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package iam
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import (
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"golang.org/x/net/context"
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pb "google.golang.org/genproto/googleapis/iam/v1"
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"google.golang.org/grpc"
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)
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// client abstracts the IAMPolicy API to allow multiple implementations.
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type client interface {
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Get(ctx context.Context, resource string) (*pb.Policy, error)
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Set(ctx context.Context, resource string, p *pb.Policy) error
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Test(ctx context.Context, resource string, perms []string) ([]string, error)
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}
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// grpcClient implements client for the standard gRPC-based IAMPolicy service.
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type grpcClient struct {
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c pb.IAMPolicyClient
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}
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func (g *grpcClient) Get(ctx context.Context, resource string) (*pb.Policy, error) {
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proto, err := g.c.GetIamPolicy(ctx, &pb.GetIamPolicyRequest{Resource: resource})
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if err != nil {
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return nil, err
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}
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return proto, nil
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}
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func (g *grpcClient) Set(ctx context.Context, resource string, p *pb.Policy) error {
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_, err := g.c.SetIamPolicy(ctx, &pb.SetIamPolicyRequest{
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Resource: resource,
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Policy: p,
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})
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return err
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}
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func (g *grpcClient) Test(ctx context.Context, resource string, perms []string) ([]string, error) {
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res, err := g.c.TestIamPermissions(ctx, &pb.TestIamPermissionsRequest{
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Resource: resource,
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Permissions: perms,
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})
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if err != nil {
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return nil, err
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}
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return res.Permissions, nil
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}
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// A Handle provides IAM operations for a resource.
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type Handle struct {
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c client
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resource string
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}
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// InternalNewHandle is for use by the Google Cloud Libraries only.
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//
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// InternalNewHandle returns a Handle for resource.
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// The conn parameter refers to a server that must support the IAMPolicy service.
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func InternalNewHandle(conn *grpc.ClientConn, resource string) *Handle {
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return InternalNewHandleClient(&grpcClient{c: pb.NewIAMPolicyClient(conn)}, resource)
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}
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// InternalNewHandleClient is for use by the Google Cloud Libraries only.
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//
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// InternalNewHandleClient returns a Handle for resource using the given
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// client implementation.
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func InternalNewHandleClient(c client, resource string) *Handle {
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return &Handle{
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c: c,
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resource: resource,
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}
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}
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// Policy retrieves the IAM policy for the resource.
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func (h *Handle) Policy(ctx context.Context) (*Policy, error) {
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proto, err := h.c.Get(ctx, h.resource)
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if err != nil {
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return nil, err
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}
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return &Policy{InternalProto: proto}, nil
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}
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// SetPolicy replaces the resource's current policy with the supplied Policy.
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//
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// If policy was created from a prior call to Get, then the modification will
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// only succeed if the policy has not changed since the Get.
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func (h *Handle) SetPolicy(ctx context.Context, policy *Policy) error {
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return h.c.Set(ctx, h.resource, policy.InternalProto)
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}
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// TestPermissions returns the subset of permissions that the caller has on the resource.
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func (h *Handle) TestPermissions(ctx context.Context, permissions []string) ([]string, error) {
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return h.c.Test(ctx, h.resource, permissions)
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}
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// A RoleName is a name representing a collection of permissions.
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type RoleName string
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// Common role names.
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const (
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Owner RoleName = "roles/owner"
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Editor RoleName = "roles/editor"
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Viewer RoleName = "roles/viewer"
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)
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const (
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// AllUsers is a special member that denotes all users, even unauthenticated ones.
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AllUsers = "allUsers"
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// AllAuthenticatedUsers is a special member that denotes all authenticated users.
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AllAuthenticatedUsers = "allAuthenticatedUsers"
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)
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// A Policy is a list of Bindings representing roles
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// granted to members.
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//
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// The zero Policy is a valid policy with no bindings.
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type Policy struct {
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// TODO(jba): when type aliases are available, put Policy into an internal package
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// and provide an exported alias here.
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// This field is exported for use by the Google Cloud Libraries only.
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// It may become unexported in a future release.
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InternalProto *pb.Policy
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}
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// Members returns the list of members with the supplied role.
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// The return value should not be modified. Use Add and Remove
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// to modify the members of a role.
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func (p *Policy) Members(r RoleName) []string {
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b := p.binding(r)
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if b == nil {
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return nil
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}
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return b.Members
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}
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// HasRole reports whether member has role r.
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func (p *Policy) HasRole(member string, r RoleName) bool {
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return memberIndex(member, p.binding(r)) >= 0
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}
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// Add adds member member to role r if it is not already present.
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// A new binding is created if there is no binding for the role.
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func (p *Policy) Add(member string, r RoleName) {
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b := p.binding(r)
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if b == nil {
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if p.InternalProto == nil {
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p.InternalProto = &pb.Policy{}
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}
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p.InternalProto.Bindings = append(p.InternalProto.Bindings, &pb.Binding{
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Role: string(r),
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Members: []string{member},
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})
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return
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}
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if memberIndex(member, b) < 0 {
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b.Members = append(b.Members, member)
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return
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}
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}
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// Remove removes member from role r if it is present.
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func (p *Policy) Remove(member string, r RoleName) {
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bi := p.bindingIndex(r)
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if bi < 0 {
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return
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}
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bindings := p.InternalProto.Bindings
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b := bindings[bi]
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mi := memberIndex(member, b)
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if mi < 0 {
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return
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}
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// Order doesn't matter for bindings or members, so to remove, move the last item
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// into the removed spot and shrink the slice.
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if len(b.Members) == 1 {
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// Remove binding.
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last := len(bindings) - 1
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bindings[bi] = bindings[last]
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bindings[last] = nil
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p.InternalProto.Bindings = bindings[:last]
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return
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}
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// Remove member.
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// TODO(jba): worry about multiple copies of m?
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last := len(b.Members) - 1
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b.Members[mi] = b.Members[last]
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b.Members[last] = ""
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b.Members = b.Members[:last]
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}
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// Roles returns the names of all the roles that appear in the Policy.
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func (p *Policy) Roles() []RoleName {
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if p.InternalProto == nil {
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return nil
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}
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var rns []RoleName
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for _, b := range p.InternalProto.Bindings {
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rns = append(rns, RoleName(b.Role))
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}
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return rns
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}
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// binding returns the Binding for the suppied role, or nil if there isn't one.
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func (p *Policy) binding(r RoleName) *pb.Binding {
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i := p.bindingIndex(r)
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if i < 0 {
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return nil
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}
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return p.InternalProto.Bindings[i]
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}
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func (p *Policy) bindingIndex(r RoleName) int {
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if p.InternalProto == nil {
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return -1
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}
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for i, b := range p.InternalProto.Bindings {
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if b.Role == string(r) {
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return i
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}
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}
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return -1
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}
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// memberIndex returns the index of m in b's Members, or -1 if not found.
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func memberIndex(m string, b *pb.Binding) int {
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if b == nil {
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return -1
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}
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for i, mm := range b.Members {
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if mm == m {
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return i
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}
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}
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return -1
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}
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