12284350326

Committed 11 Dec 2024 08:27PM UTC coverage: 57.485% (+7.9%) from 49.54%

Build # 12284350326

Build Type

Pull #9348

github

Committed by

ziggie1984

Commit Message

github: update goveralls tool

Pull Request Pull Request #9348: github: update goveralls tool

Run Details

101901 of 177264 relevant lines covered (57.49%)

24841.21 hits per line

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74.26

/invoices/modification_interceptor.go

package invoices

import (
        "errors"
        "fmt"
        "sync/atomic"

        "github.com/lightningnetwork/lnd/fn/v2"
)

var (
        // ErrInterceptorClientAlreadyConnected is an error that is returned
        // when a client tries to connect to the interceptor service while
        // another client is already connected.
        ErrInterceptorClientAlreadyConnected = errors.New(
                "interceptor client already connected",
        )

        // ErrInterceptorClientDisconnected is an error that is returned when
        // the client disconnects during an interceptor session.
        ErrInterceptorClientDisconnected = errors.New(
                "interceptor client disconnected",
        )
)

// safeCallback is a wrapper around a callback function that is safe for
// concurrent access.
type safeCallback struct {
        // callback is the actual callback function that is called when an
        // invoice is intercepted. This might be nil if no client is currently
        // connected.
        callback atomic.Pointer[HtlcModifyCallback]
}

// Set atomically sets the callback function. If a callback is already set, an
// error is returned. The returned function can be used to reset the callback to
// nil once the client is done.
func (s *safeCallback) Set(callback HtlcModifyCallback) (func(), error) {
        if !s.callback.CompareAndSwap(nil, &callback) {
                return nil, ErrInterceptorClientAlreadyConnected
        }

        return func() {
                s.callback.Store(nil)
        }, nil
}

// IsConnected returns true if a client is currently connected.
func (s *safeCallback) IsConnected() bool {
        return s.callback.Load() != nil
}

// Exec executes the callback function if it is set. If the callback is not set,
// an error is returned.
func (s *safeCallback) Exec(req HtlcModifyRequest) (*HtlcModifyResponse,
        error) {

        callback := s.callback.Load()
        if callback == nil {
                return nil, ErrInterceptorClientDisconnected
        }

        return (*callback)(req)
}

// HtlcModificationInterceptor is a service that intercepts HTLCs that aim to
// settle an invoice, enabling a subscribed client to modify certain aspects of
// those HTLCs.
type HtlcModificationInterceptor struct {
        started atomic.Bool
        stopped atomic.Bool

        // callback is the wrapped client callback function that is called when
        // an invoice is intercepted. This function gives the client the ability
        // to determine how the invoice should be settled.
        callback *safeCallback

        // quit is a channel that is closed when the interceptor is stopped.
        quit chan struct{}
}

// NewHtlcModificationInterceptor creates a new HtlcModificationInterceptor.
func NewHtlcModificationInterceptor() *HtlcModificationInterceptor {
        return &HtlcModificationInterceptor{
                callback: &safeCallback{},
                quit:     make(chan struct{}),
        }
}

// Intercept generates a new intercept session for the given invoice. The call
// blocks until the client has responded to the request or an error occurs. The
// response callback is only called if a session was created in the first place,
// which is only the case if a client is registered.
func (s *HtlcModificationInterceptor) Intercept(clientRequest HtlcModifyRequest,
        responseCallback func(HtlcModifyResponse)) error {

        // If there is no client callback set we will not handle the invoice
        // further.
        if !s.callback.IsConnected() {
                log.Debugf("Not intercepting invoice with circuit key %v, no "+
                        "intercept client connected",
                        clientRequest.ExitHtlcCircuitKey)

                return nil
        }

        // We'll block until the client has responded to the request or an error
        // occurs.
        var (
                responseChan = make(chan *HtlcModifyResponse, 1)
                errChan      = make(chan error, 1)
        )

        // The callback function will block at the client's discretion. We will
        // therefore execute it in a separate goroutine. We don't need a wait
        // group because we wait for the response directly below. The caller
        // needs to make sure they don't block indefinitely, by selecting on the
        // quit channel they receive when registering the callback.
        go func() {
                log.Debugf("Waiting for client response from invoice HTLC "+
                        "interceptor session with circuit key %v",
                        clientRequest.ExitHtlcCircuitKey)

                // By this point, we've already checked that the client callback
                // is set. However, if the client disconnected since that check
                // then Exec will return an error.
                result, err := s.callback.Exec(clientRequest)
                if err != nil {
                        _ = fn.SendOrQuit(errChan, err, s.quit)

                        return
                }

                _ = fn.SendOrQuit(responseChan, result, s.quit)
        }()

        // Wait for the client to respond or an error to occur.
        select {
        case response := <-responseChan:
                log.Debugf("Received invoice HTLC interceptor response: %v",
                        response)

                responseCallback(*response)

                return nil

        case err := <-errChan:
                log.Errorf("Error from invoice HTLC interceptor session: %v",
                        err)

                return err

        case <-s.quit:
                return ErrInterceptorClientDisconnected
        }
}

// RegisterInterceptor sets the client callback function that will be called
// when an invoice is intercepted. If a callback is already set, an error is
// returned. The returned function must be used to reset the callback to nil
// once the client is done or disconnects.
func (s *HtlcModificationInterceptor) RegisterInterceptor(
        callback HtlcModifyCallback) (func(), <-chan struct{}, error) {

        done, err := s.callback.Set(callback)
        return done, s.quit, err
}

// Start starts the service.
func (s *HtlcModificationInterceptor) Start() error {
        log.Info("HtlcModificationInterceptor starting...")

        if !s.started.CompareAndSwap(false, true) {
                return fmt.Errorf("HtlcModificationInterceptor started more" +
                        "than once")
        }

        log.Debugf("HtlcModificationInterceptor started")

        return nil
}

// Stop stops the service.
func (s *HtlcModificationInterceptor) Stop() error {
        log.Info("HtlcModificationInterceptor stopping...")

        if !s.stopped.CompareAndSwap(false, true) {
                return fmt.Errorf("HtlcModificationInterceptor stopped more" +
                        "than once")
        }

        close(s.quit)

        log.Debug("HtlcModificationInterceptor stopped")

        return nil
}

// Ensure that HtlcModificationInterceptor implements the HtlcInterceptor and
// HtlcModifier interfaces.
var _ HtlcInterceptor = (*HtlcModificationInterceptor)(nil)
var _ HtlcModifier = (*HtlcModificationInterceptor)(nil)

1	package invoices
2
3	import (
4	"errors"
5	"fmt"
6	"sync/atomic"
7
8	"github.com/lightningnetwork/lnd/fn/v2"
9	)
10
11	var (
12	// ErrInterceptorClientAlreadyConnected is an error that is returned
13	// when a client tries to connect to the interceptor service while
14	// another client is already connected.
15	ErrInterceptorClientAlreadyConnected = errors.New(
16	"interceptor client already connected",
17	)
18
19	// ErrInterceptorClientDisconnected is an error that is returned when
20	// the client disconnects during an interceptor session.
21	ErrInterceptorClientDisconnected = errors.New(
22	"interceptor client disconnected",
23	)
24	)
25
26	// safeCallback is a wrapper around a callback function that is safe for
27	// concurrent access.
28	type safeCallback struct {
29	// callback is the actual callback function that is called when an
30	// invoice is intercepted. This might be nil if no client is currently
31	// connected.
32	callback atomic.Pointer[HtlcModifyCallback]
33	}
34
35	// Set atomically sets the callback function. If a callback is already set, an
36	// error is returned. The returned function can be used to reset the callback to
37	// nil once the client is done.
38	func (s *safeCallback) Set(callback HtlcModifyCallback) (func(), error) {	3✔
39	if !s.callback.CompareAndSwap(nil, &callback) {	4✔
40	return nil, ErrInterceptorClientAlreadyConnected	1✔
41	}	1✔
42
43	return func() {	4✔
44	s.callback.Store(nil)	2✔
45	}, nil	2✔
46	}
47
48	// IsConnected returns true if a client is currently connected.
49	func (s *safeCallback) IsConnected() bool {	3✔
50	return s.callback.Load() != nil	3✔
51	}	3✔
52
53	// Exec executes the callback function if it is set. If the callback is not set,
54	// an error is returned.
55	func (s safeCallback) Exec(req HtlcModifyRequest) (HtlcModifyResponse,
56	error) {	2✔
57		2✔
58	callback := s.callback.Load()	2✔
59	if callback == nil {	2✔
60	return nil, ErrInterceptorClientDisconnected	×
61	}	×
62
63	return (*callback)(req)	2✔
64	}
65
66	// HtlcModificationInterceptor is a service that intercepts HTLCs that aim to
67	// settle an invoice, enabling a subscribed client to modify certain aspects of
68	// those HTLCs.
69	type HtlcModificationInterceptor struct {
70	started atomic.Bool
71	stopped atomic.Bool
72
73	// callback is the wrapped client callback function that is called when
74	// an invoice is intercepted. This function gives the client the ability
75	// to determine how the invoice should be settled.
76	callback *safeCallback
77
78	// quit is a channel that is closed when the interceptor is stopped.
79	quit chan struct{}
80	}
81
82	// NewHtlcModificationInterceptor creates a new HtlcModificationInterceptor.
83	func NewHtlcModificationInterceptor() *HtlcModificationInterceptor {	1✔
84	return &HtlcModificationInterceptor{	1✔
85	callback: &safeCallback{},	1✔
86	quit: make(chan struct{}),	1✔
87	}	1✔
88	}	1✔
89
90	// Intercept generates a new intercept session for the given invoice. The call
91	// blocks until the client has responded to the request or an error occurs. The
92	// response callback is only called if a session was created in the first place,
93	// which is only the case if a client is registered.
94	func (s *HtlcModificationInterceptor) Intercept(clientRequest HtlcModifyRequest,
95	responseCallback func(HtlcModifyResponse)) error {	3✔
96		3✔
97	// If there is no client callback set we will not handle the invoice	3✔
98	// further.	3✔
99	if !s.callback.IsConnected() {	4✔
100	log.Debugf("Not intercepting invoice with circuit key %v, no "+	1✔
101	"intercept client connected",	1✔
102	clientRequest.ExitHtlcCircuitKey)	1✔
103		1✔
104	return nil	1✔
105	}	1✔
106
107	// We'll block until the client has responded to the request or an error
108	// occurs.
109	var (	2✔
110	responseChan = make(chan *HtlcModifyResponse, 1)	2✔
111	errChan = make(chan error, 1)	2✔
112	)	2✔
113		2✔
114	// The callback function will block at the client's discretion. We will	2✔
115	// therefore execute it in a separate goroutine. We don't need a wait	2✔
116	// group because we wait for the response directly below. The caller	2✔
117	// needs to make sure they don't block indefinitely, by selecting on the	2✔
118	// quit channel they receive when registering the callback.	2✔
119	go func() {	4✔
120	log.Debugf("Waiting for client response from invoice HTLC "+	2✔
121	"interceptor session with circuit key %v",	2✔
122	clientRequest.ExitHtlcCircuitKey)	2✔
123		2✔
124	// By this point, we've already checked that the client callback	2✔
125	// is set. However, if the client disconnected since that check	2✔
126	// then Exec will return an error.	2✔
127	result, err := s.callback.Exec(clientRequest)	2✔
128	if err != nil {	3✔
129	_ = fn.SendOrQuit(errChan, err, s.quit)	1✔
130		1✔
131	return	1✔
132	}	1✔
133
134	_ = fn.SendOrQuit(responseChan, result, s.quit)	1✔
135	}()
136
137	// Wait for the client to respond or an error to occur.
138	select {	2✔
139	case response := <-responseChan:	1✔
140	log.Debugf("Received invoice HTLC interceptor response: %v",	1✔
141	response)	1✔
142		1✔
143	responseCallback(*response)	1✔
144		1✔
145	return nil	1✔
146
147	case err := <-errChan:	1✔
148	log.Errorf("Error from invoice HTLC interceptor session: %v",	1✔
149	err)	1✔
150		1✔
151	return err	1✔
152
153	case <-s.quit:	×
154	return ErrInterceptorClientDisconnected	×
155	}
156	}
157
158	// RegisterInterceptor sets the client callback function that will be called
159	// when an invoice is intercepted. If a callback is already set, an error is
160	// returned. The returned function must be used to reset the callback to nil
161	// once the client is done or disconnects.
162	func (s *HtlcModificationInterceptor) RegisterInterceptor(
163	callback HtlcModifyCallback) (func(), <-chan struct{}, error) {	3✔
164		3✔
165	done, err := s.callback.Set(callback)	3✔
166	return done, s.quit, err	3✔
167	}	3✔
168
169	// Start starts the service.
170	func (s *HtlcModificationInterceptor) Start() error {	×
171	log.Info("HtlcModificationInterceptor starting...")	×
172		×
173	if !s.started.CompareAndSwap(false, true) {	×
174	return fmt.Errorf("HtlcModificationInterceptor started more" +	×
175	"than once")	×
176	}	×
177
178	log.Debugf("HtlcModificationInterceptor started")	×
179		×
180	return nil	×
181	}
182
183	// Stop stops the service.
184	func (s *HtlcModificationInterceptor) Stop() error {	×
185	log.Info("HtlcModificationInterceptor stopping...")	×
186		×
187	if !s.stopped.CompareAndSwap(false, true) {	×
188	return fmt.Errorf("HtlcModificationInterceptor stopped more" +	×
189	"than once")	×
190	}	×
191
192	close(s.quit)	×
193		×
194	log.Debug("HtlcModificationInterceptor stopped")	×
195		×
196	return nil	×
197	}
198
199	// Ensure that HtlcModificationInterceptor implements the HtlcInterceptor and
200	// HtlcModifier interfaces.
201	var _ HtlcInterceptor = (*HtlcModificationInterceptor)(nil)
202	var _ HtlcModifier = (*HtlcModificationInterceptor)(nil)

lightningnetwork / lnd / 12284350326

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