1 //===-- FileCache.cpp -----------------------------------------------------===//
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 #include "lldb/Host/FileCache.h"
10 
11 #include "lldb/Host/File.h"
12 #include "lldb/Host/FileSystem.h"
13 
14 using namespace lldb;
15 using namespace lldb_private;
16 
17 FileCache *FileCache::m_instance = nullptr;
18 
19 FileCache &FileCache::GetInstance() {
20   if (m_instance == nullptr)
21     m_instance = new FileCache();
22 
23   return *m_instance;
24 }
25 
26 lldb::user_id_t FileCache::OpenFile(const FileSpec &file_spec,
27                                     File::OpenOptions flags, uint32_t mode,
28                                     Status &error) {
29   if (!file_spec) {
30     error.SetErrorString("empty path");
31     return UINT64_MAX;
32   }
33   auto file = FileSystem::Instance().Open(file_spec, flags, mode);
34   if (!file) {
35     error = file.takeError();
36     return UINT64_MAX;
37   }
38   lldb::user_id_t fd = file.get()->GetDescriptor();
39   m_cache[fd] = std::move(file.get());
40   return fd;
41 }
42 
43 bool FileCache::CloseFile(lldb::user_id_t fd, Status &error) {
44   if (fd == UINT64_MAX) {
45     error.SetErrorString("invalid file descriptor");
46     return false;
47   }
48   FDToFileMap::iterator pos = m_cache.find(fd);
49   if (pos == m_cache.end()) {
50     error.SetErrorStringWithFormat("invalid host file descriptor %" PRIu64, fd);
51     return false;
52   }
53   FileUP &file_up = pos->second;
54   if (!file_up) {
55     error.SetErrorString("invalid host backing file");
56     return false;
57   }
58   error = file_up->Close();
59   m_cache.erase(pos);
60   return error.Success();
61 }
62 
63 uint64_t FileCache::WriteFile(lldb::user_id_t fd, uint64_t offset,
64                               const void *src, uint64_t src_len,
65                               Status &error) {
66   if (fd == UINT64_MAX) {
67     error.SetErrorString("invalid file descriptor");
68     return UINT64_MAX;
69   }
70   FDToFileMap::iterator pos = m_cache.find(fd);
71   if (pos == m_cache.end()) {
72     error.SetErrorStringWithFormat("invalid host file descriptor %" PRIu64, fd);
73     return false;
74   }
75   FileUP &file_up = pos->second;
76   if (!file_up) {
77     error.SetErrorString("invalid host backing file");
78     return UINT64_MAX;
79   }
80   if (static_cast<uint64_t>(file_up->SeekFromStart(offset, &error)) != offset ||
81       error.Fail())
82     return UINT64_MAX;
83   size_t bytes_written = src_len;
84   error = file_up->Write(src, bytes_written);
85   if (error.Fail())
86     return UINT64_MAX;
87   return bytes_written;
88 }
89 
90 uint64_t FileCache::ReadFile(lldb::user_id_t fd, uint64_t offset, void *dst,
91                              uint64_t dst_len, Status &error) {
92   if (fd == UINT64_MAX) {
93     error.SetErrorString("invalid file descriptor");
94     return UINT64_MAX;
95   }
96   FDToFileMap::iterator pos = m_cache.find(fd);
97   if (pos == m_cache.end()) {
98     error.SetErrorStringWithFormat("invalid host file descriptor %" PRIu64, fd);
99     return false;
100   }
101   FileUP &file_up = pos->second;
102   if (!file_up) {
103     error.SetErrorString("invalid host backing file");
104     return UINT64_MAX;
105   }
106   if (static_cast<uint64_t>(file_up->SeekFromStart(offset, &error)) != offset ||
107       error.Fail())
108     return UINT64_MAX;
109   size_t bytes_read = dst_len;
110   error = file_up->Read(dst, bytes_read);
111   if (error.Fail())
112     return UINT64_MAX;
113   return bytes_read;
114 }
115