Update

vendor/tailscale.com/util/syspolicy/policyclient/policyclient.go

@@ -0,0 +1,145 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Package policyclient contains the minimal syspolicy interface as needed by
+// client code using syspolicy. It's the part that's always linked in, even if the rest
+// of syspolicy is omitted from the build.
+package policyclient
+
+import (
+	"time"
+
+	"tailscale.com/util/syspolicy/pkey"
+	"tailscale.com/util/syspolicy/ptype"
+	"tailscale.com/util/testenv"
+)
+
+// Client is the interface between code making questions about the system policy
+// and the actual implementation.
+type Client interface {
+	// GetString returns a string policy setting with the specified key,
+	// or defaultValue (and a nil error) if it does not exist.
+	GetString(key pkey.Key, defaultValue string) (string, error)
+
+	// GetStringArray returns a string array policy setting with the specified key,
+	// or defaultValue (and a nil error) if it does not exist.
+	GetStringArray(key pkey.Key, defaultValue []string) ([]string, error)
+
+	// GetBoolean returns a boolean policy setting with the specified key,
+	// or defaultValue (and a nil error) if it does not exist.
+	GetBoolean(key pkey.Key, defaultValue bool) (bool, error)
+
+	// GetUint64 returns a numeric policy setting with the specified key,
+	// or defaultValue (and a nil error) if it does not exist.
+	GetUint64(key pkey.Key, defaultValue uint64) (uint64, error)
+
+	// GetDuration loads a policy from the registry that can be managed by an
+	// enterprise policy management system and describes a duration for some
+	// action. The registry value should be a string that time.ParseDuration
+	// understands. If the registry value is "" or can not be processed,
+	// defaultValue (and a nil error) is returned instead.
+	GetDuration(key pkey.Key, defaultValue time.Duration) (time.Duration, error)
+
+	// GetPreferenceOption loads a policy from the registry that can be
+	// managed by an enterprise policy management system and allows administrative
+	// overrides of users' choices in a way that we do not want tailcontrol to have
+	// the authority to set. It describes user-decides/always/never options, where
+	// "always" and "never" remove the user's ability to make a selection. If not
+	// present or set to a different value, defaultValue (and a nil error) is returned.
+	GetPreferenceOption(key pkey.Key, defaultValue ptype.PreferenceOption) (ptype.PreferenceOption, error)
+
+	// GetVisibility returns whether a UI element should be visible based on
+	// the system's configuration.
+	// If unconfigured, implementations should return [ptype.VisibleByPolicy]
+	// and a nil error.
+	GetVisibility(key pkey.Key) (ptype.Visibility, error)
+
+	// SetDebugLoggingEnabled enables or disables debug logging for the policy client.
+	SetDebugLoggingEnabled(enabled bool)
+
+	// HasAnyOf returns whether at least one of the specified policy settings is
+	// configured, or an error if no keys are provided or the check fails.
+	HasAnyOf(keys ...pkey.Key) (bool, error)
+
+	// RegisterChangeCallback registers a callback function that will be called
+	// whenever a policy change is detected. It returns a function to unregister
+	// the callback and an error if the registration fails.
+	RegisterChangeCallback(cb func(PolicyChange)) (unregister func(), err error)
+}
+
+// Get returns a non-nil [Client] implementation as a function of the
+// build tags. It returns a no-op implementation if the full syspolicy
+// package is omitted from the build, or in tests.
+func Get() Client {
+	if testenv.InTest() {
+		// This is a little redundant (the Windows implementation at least
+		// already does this) but it's here for redundancy and clarity, that we
+		// don't want to accidentally use the real system policy when running
+		// tests.
+		return NoPolicyClient{}
+	}
+	return client
+}
+
+// RegisterClientImpl registers a [Client] implementation to be returned by
+// [Get].
+func RegisterClientImpl(c Client) {
+	client = c
+}
+
+var client Client = NoPolicyClient{}
+
+// PolicyChange is the interface representing a change in policy settings.
+type PolicyChange interface {
+	// HasChanged reports whether the policy setting identified by the given key
+	// has changed.
+	HasChanged(pkey.Key) bool
+
+	// HasChangedAnyOf reports whether any of the provided policy settings
+	// changed in this change.
+	HasChangedAnyOf(keys ...pkey.Key) bool
+}
+
+// NoPolicyClient is a no-op implementation of [Client] that only
+// returns default values.
+type NoPolicyClient struct{}
+
+var _ Client = NoPolicyClient{}
+
+func (NoPolicyClient) GetBoolean(key pkey.Key, defaultValue bool) (bool, error) {
+	return defaultValue, nil
+}
+
+func (NoPolicyClient) GetString(key pkey.Key, defaultValue string) (string, error) {
+	return defaultValue, nil
+}
+
+func (NoPolicyClient) GetStringArray(key pkey.Key, defaultValue []string) ([]string, error) {
+	return defaultValue, nil
+}
+
+func (NoPolicyClient) GetUint64(key pkey.Key, defaultValue uint64) (uint64, error) {
+	return defaultValue, nil
+}
+
+func (NoPolicyClient) GetDuration(name pkey.Key, defaultValue time.Duration) (time.Duration, error) {
+	return defaultValue, nil
+}
+
+func (NoPolicyClient) GetPreferenceOption(name pkey.Key, defaultValue ptype.PreferenceOption) (ptype.PreferenceOption, error) {
+	return defaultValue, nil
+}
+
+func (NoPolicyClient) GetVisibility(name pkey.Key) (ptype.Visibility, error) {
+	return ptype.VisibleByPolicy, nil
+}
+
+func (NoPolicyClient) HasAnyOf(keys ...pkey.Key) (bool, error) {
+	return false, nil
+}
+
+func (NoPolicyClient) SetDebugLoggingEnabled(enabled bool) {}
+
+func (NoPolicyClient) RegisterChangeCallback(cb func(PolicyChange)) (unregister func(), err error) {
+	return func() {}, nil
+}