1 | //===-- UserIDResolver.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_USERIDRESOLVER_H |
10 | #define LLDB_UTILITY_USERIDRESOLVER_H |
11 | |
12 | #include "llvm/ADT/DenseMap.h" |
13 | #include "llvm/ADT/StringRef.h" |
14 | #include <mutex> |
15 | #include <optional> |
16 | |
17 | namespace lldb_private { |
18 | |
19 | /// An abstract interface for things that know how to map numeric user/group IDs |
20 | /// into names. It caches the resolved names to avoid repeating expensive |
21 | /// queries. The cache is internally protected by a mutex, so concurrent queries |
22 | /// are safe. |
23 | class UserIDResolver { |
24 | public: |
25 | typedef uint32_t id_t; |
26 | virtual ~UserIDResolver(); // anchor |
27 | |
28 | std::optional<llvm::StringRef> GetUserName(id_t uid) { |
29 | return Get(id: uid, cache&: m_uid_cache, do_get: &UserIDResolver::DoGetUserName); |
30 | } |
31 | std::optional<llvm::StringRef> GetGroupName(id_t gid) { |
32 | return Get(id: gid, cache&: m_gid_cache, do_get: &UserIDResolver::DoGetGroupName); |
33 | } |
34 | |
35 | /// Returns a resolver which returns a failure value for each query. Useful as |
36 | /// a fallback value for the case when we know all lookups will fail. |
37 | static UserIDResolver &GetNoopResolver(); |
38 | |
39 | protected: |
40 | virtual std::optional<std::string> DoGetUserName(id_t uid) = 0; |
41 | virtual std::optional<std::string> DoGetGroupName(id_t gid) = 0; |
42 | |
43 | private: |
44 | using Map = llvm::DenseMap<id_t, std::optional<std::string>>; |
45 | |
46 | std::optional<llvm::StringRef> |
47 | Get(id_t id, Map &cache, |
48 | std::optional<std::string> (UserIDResolver::*do_get)(id_t)); |
49 | |
50 | std::mutex m_mutex; |
51 | Map m_uid_cache; |
52 | Map m_gid_cache; |
53 | }; |
54 | |
55 | } // namespace lldb_private |
56 | |
57 | #endif // LLDB_UTILITY_USERIDRESOLVER_H |
58 | |