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
11#if !defined(_WIN32)
12#include <sys/stat.h>
13#include <sys/types.h>
14#include <unistd.h>
15#endif
16
17#include <chrono>
18#include <fstream>
19#include <future>
20#include <optional>
21#include <thread>
22
23#include "llvm/Support/FileSystem.h"
24
25#include "lldb/lldb-defines.h"
26
27using namespace llvm;
28
29namespace lldb_dap {
30
31FifoFile::FifoFile(StringRef path) : m_path(path) {}
32
33FifoFile::~FifoFile() {
34#if !defined(_WIN32)
35 unlink(name: m_path.c_str());
36#endif
37}
38
39Expected<std::shared_ptr<FifoFile>> CreateFifoFile(StringRef path) {
40#if defined(_WIN32)
41 return createStringError(inconvertibleErrorCode(), "Unimplemented");
42#else
43 if (int err = mkfifo(path: path.data(), mode: 0600))
44 return createStringError(EC: std::error_code(err, std::generic_category()),
45 Fmt: "Couldn't create fifo file: %s", Vals: path.data());
46 return std::make_shared<FifoFile>(args&: path);
47#endif
48}
49
50FifoFileIO::FifoFileIO(StringRef fifo_file, StringRef other_endpoint_name)
51 : m_fifo_file(fifo_file), m_other_endpoint_name(other_endpoint_name) {}
52
53Expected<json::Value> FifoFileIO::ReadJSON(std::chrono::milliseconds timeout) {
54 // We use a pointer for this future, because otherwise its normal destructor
55 // would wait for the getline to end, rendering the timeout useless.
56 std::optional<std::string> line;
57 std::future<void> *future =
58 new std::future<void>(std::async(policy: std::launch::async, fn: [&]() {
59 std::ifstream reader(m_fifo_file, std::ifstream::in);
60 std::string buffer;
61 std::getline(is&: reader, str&: buffer);
62 if (!buffer.empty())
63 line = buffer;
64 }));
65 if (future->wait_for(rel: timeout) == std::future_status::timeout || !line)
66 // Indeed this is a leak, but it's intentional. "future" obj destructor
67 // will block on waiting for the worker thread to join. And the worker
68 // thread might be stuck in blocking I/O. Intentionally leaking the obj
69 // as a hack to avoid blocking main thread, and adding annotation to
70 // supress static code inspection warnings
71
72 // coverity[leaked_storage]
73 return createStringError(EC: inconvertibleErrorCode(),
74 S: "Timed out trying to get messages from the " +
75 m_other_endpoint_name);
76 delete future;
77 return json::parse(JSON: *line);
78}
79
80Error FifoFileIO::SendJSON(const json::Value &json,
81 std::chrono::milliseconds timeout) {
82 bool done = false;
83 std::future<void> *future =
84 new std::future<void>(std::async(policy: std::launch::async, fn: [&]() {
85 std::ofstream writer(m_fifo_file, std::ofstream::out);
86 writer << JSONToString(json) << std::endl;
87 done = true;
88 }));
89 if (future->wait_for(rel: timeout) == std::future_status::timeout || !done) {
90 // Indeed this is a leak, but it's intentional. "future" obj destructor will
91 // block on waiting for the worker thread to join. And the worker thread
92 // might be stuck in blocking I/O. Intentionally leaking the obj as a hack
93 // to avoid blocking main thread, and adding annotation to supress static
94 // code inspection warnings"
95
96 // coverity[leaked_storage]
97 return createStringError(EC: inconvertibleErrorCode(),
98 S: "Timed out trying to send messages to the " +
99 m_other_endpoint_name);
100 }
101 delete future;
102 return Error::success();
103}
104
105} // namespace lldb_dap
106

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