1 /* 2 * Copyright (C) 2018 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include <sys/stat.h> 18 19 #include "perfetto/base/file_utils.h" 20 21 #include "perfetto/base/logging.h" 22 #include "perfetto/base/scoped_file.h" 23 24 namespace perfetto { 25 namespace base { 26 namespace { 27 constexpr size_t kBufSize = 2048; 28 } 29 30 bool ReadFile(const std::string& path, std::string* out) { 31 // Do not override existing data in string. 32 size_t i = out->size(); 33 34 base::ScopedFile fd = base::OpenFile(path.c_str(), O_RDONLY); 35 if (!fd) 36 return false; 37 38 struct stat buf {}; 39 if (fstat(*fd, &buf) != -1) { 40 if (buf.st_size > 0) 41 out->resize(i + static_cast<size_t>(buf.st_size)); 42 } 43 44 ssize_t bytes_read; 45 for (;;) { 46 if (out->size() < i + kBufSize) 47 out->resize(out->size() + kBufSize); 48 49 bytes_read = PERFETTO_EINTR(read(fd.get(), &((*out)[i]), kBufSize)); 50 if (bytes_read > 0) { 51 i += static_cast<size_t>(bytes_read); 52 } else { 53 out->resize(i); 54 return bytes_read == 0; 55 } 56 } 57 } 58 59 } // namespace base 60 } // namespace perfetto 61
