1//===-- Timeout.h -----------------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLDB_UTILITY_TIMEOUT_H
10#define LLDB_UTILITY_TIMEOUT_H
11
12#include "llvm/ADT/Optional.h"
13#include "llvm/Support/Chrono.h"
14#include "llvm/Support/FormatProviders.h"
15
16namespace lldb_private {
17
18// A general purpose class for representing timeouts for various APIs. It's
19// basically an llvm::Optional<std::chrono::duration<int64_t, Ratio>>, but we
20// customize it a bit to enable the standard chrono implicit conversions (e.g.
21// from Timeout<std::milli> to Timeout<std::micro>.
22//
23// The intended meaning of the values is:
24// - llvm::None - no timeout, the call should wait forever - 0 - poll, only
25// complete the call if it will not block - >0 - wait for a given number of
26// units for the result
27template <typename Ratio>
28class Timeout : public llvm::Optional<std::chrono::duration<int64_t, Ratio>> {
29private:
30 template <typename Ratio2> using Dur = std::chrono::duration<int64_t, Ratio2>;
31 template <typename Rep2, typename Ratio2>
32 using EnableIf = std::enable_if<
33 std::is_convertible<std::chrono::duration<Rep2, Ratio2>,
34 std::chrono::duration<int64_t, Ratio>>::value>;
35
36 using Base = llvm::Optional<Dur<Ratio>>;
37
38public:
39 Timeout(llvm::NoneType none) : Base(none) {}
40 Timeout(const Timeout &other) = default;
41
42 template <typename Ratio2,
43 typename = typename EnableIf<int64_t, Ratio2>::type>
44 Timeout(const Timeout<Ratio2> &other)
45 : Base(other ? Base(Dur<Ratio>(*other)) : llvm::None) {}
46
47 template <typename Rep2, typename Ratio2,
48 typename = typename EnableIf<Rep2, Ratio2>::type>
49 Timeout(const std::chrono::duration<Rep2, Ratio2> &other)
50 : Base(Dur<Ratio>(other)) {}
51};
52
53} // namespace lldb_private
54
55namespace llvm {
56template<typename Ratio>
57struct format_provider<lldb_private::Timeout<Ratio>, void> {
58 static void format(const lldb_private::Timeout<Ratio> &timeout,
59 raw_ostream &OS, StringRef Options) {
60 typedef typename lldb_private::Timeout<Ratio>::value_type Dur;
61
62 if (!timeout)
63 OS << "<infinite>";
64 else
65 format_provider<Dur>::format(*timeout, OS, Options);
66 }
67};
68}
69
70#endif // LLDB_UTILITY_TIMEOUT_H
71