1//===-- Progress.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_CORE_PROGRESS_H
10#define LLDB_CORE_PROGRESS_H
11
12#include "lldb/Utility/ConstString.h"
13#include "lldb/lldb-types.h"
14#include <atomic>
15#include <mutex>
16#include <optional>
17
18namespace lldb_private {
19
20/// A Progress indicator helper class.
21///
22/// Any potentially long running sections of code in LLDB should report
23/// progress so that clients are aware of delays that might appear during
24/// debugging. Delays commonly include indexing debug information, parsing
25/// symbol tables for object files, downloading symbols from remote
26/// repositories, and many more things.
27///
28/// The Progress class helps make sure that progress is correctly reported
29/// and will always send an initial progress update, updates when
30/// Progress::Increment() is called, and also will make sure that a progress
31/// completed update is reported even if the user doesn't explicitly cause one
32/// to be sent.
33///
34/// The progress is reported via a callback whose type is ProgressCallback:
35///
36///   typedef void (*ProgressCallback)(uint64_t progress_id,
37///                                    const char *message,
38///                                    uint64_t completed,
39///                                    uint64_t total,
40///                                    void *baton);
41///
42/// This callback will always initially be called with "completed" set to zero
43/// and "total" set to the total amount specified in the contructor. This is
44/// considered the progress start event. As Progress::Increment() is called,
45/// the callback will be called as long as the Progress::m_completed has not
46/// yet exceeded the Progress::m_total. When the callback is called with
47/// Progress::m_completed == Progress::m_total, that is considered a progress
48/// completed event. If Progress::m_completed is non-zero and less than
49/// Progress::m_total, then this is considered a progress update event.
50///
51/// This callback will be called in the destructor if Progress::m_completed is
52/// not equal to Progress::m_total with the "completed" set to
53/// Progress::m_total. This ensures we always send a progress completed update
54/// even if the user does not.
55
56class Progress {
57public:
58  /// Construct a progress object that will report information.
59  ///
60  /// The constructor will create a unique progress reporting object and
61  /// immediately send out a progress update by calling the installed callback
62  /// with completed set to zero out of the specified total.
63  ///
64  /// @param [in] title The title of this progress activity.
65  ///
66  /// @param [in] total The total units of work to be done if specified, if
67  /// set to std::nullopt then an indeterminate progress indicator should be
68  /// displayed.
69  ///
70  /// @param [in] debugger An optional debugger pointer to specify that this
71  /// progress is to be reported only to specific debuggers.
72  Progress(std::string title, std::string details = {},
73           std::optional<uint64_t> total = std::nullopt,
74           lldb_private::Debugger *debugger = nullptr);
75
76  /// Destroy the progress object.
77  ///
78  /// If the progress has not yet sent a completion update, the destructor
79  /// will send out a notification where the completed == m_total. This ensures
80  /// that we always send out a progress complete notification.
81  ~Progress();
82
83  /// Increment the progress and send a notification to the intalled callback.
84  ///
85  /// If incrementing ends up exceeding m_total, m_completed will be updated
86  /// to match m_total and no subsequent progress notifications will be sent.
87  /// If no total was specified in the constructor, this function will not do
88  /// anything nor send any progress updates.
89  ///
90  /// @param [in] amount The amount to increment m_completed by.
91  ///
92  /// @param [in] an optional message associated with this update.
93  void Increment(uint64_t amount = 1,
94                 std::optional<std::string> updated_detail = {});
95
96private:
97  void ReportProgress();
98  static std::atomic<uint64_t> g_id;
99  /// The title of the progress activity.
100  std::string m_title;
101  std::string m_details;
102  std::mutex m_mutex;
103  /// A unique integer identifier for progress reporting.
104  const uint64_t m_id;
105  /// How much work ([0...m_total]) that has been completed.
106  uint64_t m_completed;
107  /// Total amount of work, use a std::nullopt in the constructor for non
108  /// deterministic progress.
109  uint64_t m_total;
110  /// The optional debugger ID to report progress to. If this has no value then
111  /// all debuggers will receive this event.
112  std::optional<lldb::user_id_t> m_debugger_id;
113  /// Set to true when progress has been reported where m_completed == m_total
114  /// to ensure that we don't send progress updates after progress has
115  /// completed.
116  bool m_complete = false;
117};
118
119} // namespace lldb_private
120
121#endif // LLDB_CORE_PROGRESS_H
122