86 lines
2.8 KiB
C++
86 lines
2.8 KiB
C++
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/*
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* Copyright 2017 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#include "ok.h"
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struct SerialEngine : Engine {
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static std::unique_ptr<Engine> Factory(Options) {
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SerialEngine engine;
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return move_unique(engine);
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}
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bool crashproof() override { return false; }
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std::future<Status> spawn(std::function<Status(void)> fn) override {
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return std::async(std::launch::deferred, fn);
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}
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};
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static Register serial("serial",
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"Run tasks serially on the main thread of a single process.",
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SerialEngine::Factory);
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struct ThreadEngine : Engine {
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static std::unique_ptr<Engine> Factory(Options) {
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ThreadEngine engine;
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return move_unique(engine);
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}
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bool crashproof() override { return false; }
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std::future<Status> spawn(std::function<Status(void)> fn) override {
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return std::async(std::launch::async, fn);
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}
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};
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static Register thread("thread",
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"Run each task on its own thread of a single process.",
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ThreadEngine::Factory);
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#if !defined(_MSC_VER)
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#include <sys/wait.h>
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#include <unistd.h>
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struct ForkEngine : Engine {
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static std::unique_ptr<Engine> Factory(Options) {
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ForkEngine engine;
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return move_unique(engine);
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}
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bool crashproof() override { return true; }
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std::future<Status> spawn(std::function<Status(void)> fn) override {
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switch (fork()) {
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case 0:
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// We are the spawned child process.
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// Run fn() and exit() with its Status as our return code.
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_exit((int)fn());
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case -1:
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// The OS won't let us fork() another process right now.
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// We'll need to wait for at least one live task to finish and try again.
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return std::future<Status>();
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default:
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// We succesfully spawned a child process!
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// This will wait for any spawned process to finish and return its Status.
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return std::async(std::launch::deferred, [] {
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do {
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int status;
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if (wait(&status) > 0) {
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return WIFEXITED(status) ? (Status)WEXITSTATUS(status)
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: Status::Crashed;
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}
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} while (errno == EINTR);
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return Status::None;
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});
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}
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}
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};
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static Register _fork("fork",
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"Run each task in an independent process with fork().",
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ForkEngine::Factory);
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#endif
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