1//===-- FifoFiles.cpp -------------------------------------------*- C++ -*-===//
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 "FifoFiles.h"
10#include "JSONUtils.h"
11
12#if !defined(_WIN32)
13#include <sys/stat.h>
14#include <sys/types.h>
15#include <unistd.h>
16#endif
17
18#include <chrono>
19#include <fstream>
20#include <future>
21#include <optional>
22
23using namespace llvm;
24
25namespace lldb_dap {
26
27FifoFile::FifoFile(StringRef path) : m_path(path) {}
28
29FifoFile::~FifoFile() {
30#if !defined(_WIN32)
31 unlink(name: m_path.c_str());
32#endif
33}
34
35Expected<std::shared_ptr<FifoFile>> CreateFifoFile(StringRef path) {
36#if defined(_WIN32)
37 return createStringError(inconvertibleErrorCode(), "Unimplemented");
38#else
39 if (int err = mkfifo(path: path.data(), mode: 0600))
40 return createStringError(EC: std::error_code(err, std::generic_category()),
41 Fmt: "Couldn't create fifo file: %s", Vals: path.data());
42 return std::make_shared<FifoFile>(args&: path);
43#endif
44}
45
46FifoFileIO::FifoFileIO(StringRef fifo_file, StringRef other_endpoint_name)
47 : m_fifo_file(fifo_file), m_other_endpoint_name(other_endpoint_name) {}
48
49Expected<json::Value> FifoFileIO::ReadJSON(std::chrono::milliseconds timeout) {
50 // We use a pointer for this future, because otherwise its normal destructor
51 // would wait for the getline to end, rendering the timeout useless.
52 std::optional<std::string> line;
53 std::future<void> *future =
54 new std::future<void>(std::async(policy: std::launch::async, fn: [&]() {
55 std::ifstream reader(m_fifo_file, std::ifstream::in);
56 std::string buffer;
57 std::getline(is&: reader, str&: buffer);
58 if (!buffer.empty())
59 line = buffer;
60 }));
61 if (future->wait_for(rel: timeout) == std::future_status::timeout || !line)
62 // Indeed this is a leak, but it's intentional. "future" obj destructor
63 // will block on waiting for the worker thread to join. And the worker
64 // thread might be stuck in blocking I/O. Intentionally leaking the obj
65 // as a hack to avoid blocking main thread, and adding annotation to
66 // supress static code inspection warnings
67
68 // coverity[leaked_storage]
69 return createStringError(EC: inconvertibleErrorCode(),
70 S: "Timed out trying to get messages from the " +
71 m_other_endpoint_name);
72 delete future;
73 return json::parse(JSON: *line);
74}
75
76Error FifoFileIO::SendJSON(const json::Value &json,
77 std::chrono::milliseconds timeout) {
78 bool done = false;
79 std::future<void> *future =
80 new std::future<void>(std::async(policy: std::launch::async, fn: [&]() {
81 std::ofstream writer(m_fifo_file, std::ofstream::out);
82 writer << JSONToString(json) << std::endl;
83 done = true;
84 }));
85 if (future->wait_for(rel: timeout) == std::future_status::timeout || !done) {
86 // Indeed this is a leak, but it's intentional. "future" obj destructor will
87 // block on waiting for the worker thread to join. And the worker thread
88 // might be stuck in blocking I/O. Intentionally leaking the obj as a hack
89 // to avoid blocking main thread, and adding annotation to supress static
90 // code inspection warnings"
91
92 // coverity[leaked_storage]
93 return createStringError(EC: inconvertibleErrorCode(),
94 S: "Timed out trying to send messages to the " +
95 m_other_endpoint_name);
96 }
97 delete future;
98 return Error::success();
99}
100
101} // namespace lldb_dap
102

source code of lldb/tools/lldb-dap/FifoFiles.cpp