110 lines
3.0 KiB
C++
110 lines
3.0 KiB
C++
/*
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* Copyright (C) 2020 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "common/libs/fs/shared_fd_stream.h"
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#include <cstdio>
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#include <streambuf>
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#include "common/libs/fs/shared_buf.h"
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namespace cuttlefish {
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SharedFDStreambuf::SharedFDStreambuf(SharedFD shared_fd)
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: shared_fd_(shared_fd) {}
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int SharedFDStreambuf::underflow() {
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if (gptr() < egptr()) {
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return *gptr();
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}
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size_t unget_size = 0;
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constexpr size_t bytes_to_read = kBufferSize - kUngetSize;
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if (read_buffer_ == nullptr) {
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read_buffer_ = std::make_unique<char[]>(kBufferSize);
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} else {
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unget_size = std::min(gptr() - eback(), kUngetSize);
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std::memcpy(read_buffer_.get(),
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read_buffer_.get() + kBufferSize - unget_size,
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unget_size);
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}
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ssize_t bytes_read = ReadExact(shared_fd_,
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read_buffer_.get() + unget_size,
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bytes_to_read);
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setg(read_buffer_.get(),
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read_buffer_.get() + unget_size,
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read_buffer_.get() + unget_size + bytes_read);
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if (bytes_read <= 0 || in_avail() == 0) {
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return EOF;
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}
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return static_cast<int>(*gptr());
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}
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std::streamsize SharedFDStreambuf::xsgetn(char* dst, std::streamsize count) {
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std::streamsize bytes_read = 0;
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while (bytes_read < count) {
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if (in_avail() == 0) {
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if (underflow() == EOF) {
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break;
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}
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}
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std::streamsize buffer_count =
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std::min(static_cast<std::streamsize>(in_avail()), count - bytes_read);
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std::memcpy(dst + bytes_read, gptr(), buffer_count);
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gbump(buffer_count);
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bytes_read += buffer_count;
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}
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return bytes_read;
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}
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int SharedFDStreambuf::overflow(int c) {
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if (c != EOF) {
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char z = c;
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if (WriteAll(shared_fd_, &z, 1) != 1) {
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return EOF;
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}
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}
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return c;
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}
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std::streamsize SharedFDStreambuf::xsputn(const char* src,
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std::streamsize count) {
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return static_cast<std::streamsize>(
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WriteAll(shared_fd_, src, static_cast<std::size_t>(count)));
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}
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int SharedFDStreambuf::pbackfail(int c) {
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if (c != EOF) {
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if (gptr() != eback()) {
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gbump(-1);
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*(gptr()) = c;
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return c;
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}
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}
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return EOF;
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}
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SharedFDOstream::SharedFDOstream(SharedFD shared_fd)
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: std::ostream(nullptr), buf_(shared_fd) { rdbuf(&buf_); }
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SharedFDIstream::SharedFDIstream(SharedFD shared_fd)
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: std::istream(nullptr), buf_(shared_fd) { rdbuf(&buf_); }
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} // namespace cuttlefish
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