1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
|
// Copyright 2025 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef REMOTING_HOST_BASE_LOGGABLE_H_
#define REMOTING_HOST_BASE_LOGGABLE_H_
#include <memory>
#include <ostream>
#include <string>
#include "base/location.h"
#include "base/types/expected.h"
namespace remoting {
// A class designed to be used as the error type for a base::expected value when
// a more structured error type is not useful or practical.
//
// Instances contain both an initial error message (e.g., "Input/output error")
// along with any additional context added by higher levels (e.g., "While
// reading configuration file: foo.conf").
//
// The resulting chain can be printed or logged using the stream insertion
// operator. E.g.,
//
// LOG(ERROR) << loggable;
class Loggable {
public:
// Constructs an empty loggable only suitable as an assignment target.
Loggable();
// Constructs a loggable with the given code location and message.
Loggable(base::Location from_here, std::string message);
// Copyable and movable.
Loggable(const Loggable&);
Loggable(Loggable&&);
Loggable& operator=(const Loggable&);
Loggable& operator=(Loggable&&);
~Loggable();
// Adds a context entry to this.
void AddContext(base::Location from_here, std::string context);
// Convenience method to add a context entry and wrap this as an unexpected
// value. Allows, e.g.,
//
// return std::move(result.error()).UnexpectedWithContext(
// FROM_HERE, "While doing foo");
base::unexpected<Loggable> UnexpectedWithContext(base::Location from_here,
std::string context) &&;
std::string ToString() const;
friend std::ostream& operator<<(std::ostream&, const Loggable&);
private:
// Storing the message and context out-of-line allows Loggable to be the size
// of a single pointer (keeping base::expected instances compact) at the
// expense of an additional indirection in the error case.
class Inner;
std::unique_ptr<Inner> inner_;
};
std::ostream& operator<<(std::ostream&, const Loggable&);
} // namespace remoting
#endif // REMOTING_HOST_BASE_LOGGABLE_H_
|
