output.cc (2109B)
1 // Copyright 2017 The Abseil Authors. 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 // https://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 "absl/strings/internal/str_format/output.h" 16 17 #include <errno.h> 18 #include <cstring> 19 20 namespace absl { 21 ABSL_NAMESPACE_BEGIN 22 namespace str_format_internal { 23 24 namespace { 25 struct ClearErrnoGuard { 26 ClearErrnoGuard() : old_value(errno) { errno = 0; } 27 ~ClearErrnoGuard() { 28 if (!errno) errno = old_value; 29 } 30 int old_value; 31 }; 32 } // namespace 33 34 void BufferRawSink::Write(string_view v) { 35 size_t to_write = std::min(v.size(), size_); 36 if (to_write > 0) { 37 std::memcpy(buffer_, v.data(), to_write); 38 buffer_ += to_write; 39 size_ -= to_write; 40 } 41 total_written_ += v.size(); 42 } 43 44 void FILERawSink::Write(string_view v) { 45 while (!v.empty() && !error_) { 46 // Reset errno to zero in case the libc implementation doesn't set errno 47 // when a failure occurs. 48 ClearErrnoGuard guard; 49 50 if (size_t result = std::fwrite(v.data(), 1, v.size(), output_)) { 51 // Some progress was made. 52 count_ += result; 53 v.remove_prefix(result); 54 } else { 55 if (errno == EINTR) { 56 continue; 57 } else if (errno) { 58 error_ = errno; 59 } else if (std::ferror(output_)) { 60 // Non-POSIX compliant libc implementations may not set errno, so we 61 // have check the streams error indicator. 62 error_ = EBADF; 63 } else { 64 // We're likely on a non-POSIX system that encountered EINTR but had no 65 // way of reporting it. 66 continue; 67 } 68 } 69 } 70 } 71 72 } // namespace str_format_internal 73 ABSL_NAMESPACE_END 74 } // namespace absl