1 // Copyright 2017 Google LLC
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 #include "filesystem_for_testing.h"
16
17 #include <cassert>
18 #include <climits>
19 #include <cstdio>
20 #include <cstring>
21 #include <utility>
22
23 namespace cpu_features {
24
FakeFile(int file_descriptor,const char * content)25 FakeFile::FakeFile(int file_descriptor, const char* content)
26 : file_descriptor_(file_descriptor), content_(content) {}
27
~FakeFile()28 FakeFile::~FakeFile() { assert(!opened_); }
29
Open()30 void FakeFile::Open() {
31 assert(!opened_);
32 opened_ = true;
33 }
34
Close()35 void FakeFile::Close() {
36 assert(opened_);
37 opened_ = false;
38 }
39
Read(int fd,void * buf,size_t count)40 int FakeFile::Read(int fd, void* buf, size_t count) {
41 assert(count < INT_MAX);
42 assert(fd == file_descriptor_);
43 const size_t remainder = content_.size() - head_index_;
44 const size_t read = count > remainder ? remainder : count;
45 memcpy(buf, content_.data() + head_index_, read);
46 head_index_ += read;
47 assert(read < INT_MAX);
48 return (int)read;
49 }
50
Reset()51 void FakeFilesystem::Reset() { files_.clear(); }
52
CreateFile(const std::string & filename,const char * content)53 FakeFile* FakeFilesystem::CreateFile(const std::string& filename,
54 const char* content) {
55 auto& file = files_[filename];
56 file =
57 std::unique_ptr<FakeFile>(new FakeFile(next_file_descriptor_++, content));
58 return file.get();
59 }
60
FindFileOrNull(const std::string & filename) const61 FakeFile* FakeFilesystem::FindFileOrNull(const std::string& filename) const {
62 const auto itr = files_.find(filename);
63 return itr == files_.end() ? nullptr : itr->second.get();
64 }
65
FindFileOrDie(const int file_descriptor) const66 FakeFile* FakeFilesystem::FindFileOrDie(const int file_descriptor) const {
67 for (const auto& filename_file_pair : files_) {
68 FakeFile* const file_ptr = filename_file_pair.second.get();
69 if (file_ptr->GetFileDescriptor() == file_descriptor) {
70 return file_ptr;
71 }
72 }
73 assert(false);
74 return nullptr;
75 }
76
77 static FakeFilesystem* kFilesystem = new FakeFilesystem();
78
GetEmptyFilesystem()79 FakeFilesystem& GetEmptyFilesystem() {
80 kFilesystem->Reset();
81 return *kFilesystem;
82 }
83
CpuFeatures_OpenFile(const char * filename)84 extern "C" int CpuFeatures_OpenFile(const char* filename) {
85 auto* const file = kFilesystem->FindFileOrNull(filename);
86 if (file) {
87 file->Open();
88 return file->GetFileDescriptor();
89 }
90 return -1;
91 }
92
CpuFeatures_CloseFile(int file_descriptor)93 extern "C" void CpuFeatures_CloseFile(int file_descriptor) {
94 kFilesystem->FindFileOrDie(file_descriptor)->Close();
95 }
96
CpuFeatures_ReadFile(int file_descriptor,void * buffer,size_t buffer_size)97 extern "C" int CpuFeatures_ReadFile(int file_descriptor, void* buffer,
98 size_t buffer_size) {
99 return kFilesystem->FindFileOrDie(file_descriptor)
100 ->Read(file_descriptor, buffer, buffer_size);
101 }
102
103 } // namespace cpu_features
104