6024e5c395
clang 20.0.0 (based on r547379) from build 12806354. Bug: http://b/379133546 Test: N/A Change-Id: I2eb8938af55d809de674be63cb30cf27e801862b Upstream-Commit: ad834e67b1105d15ef907f6255d4c96e8e733f57
106 lines
3.7 KiB
C++
106 lines
3.7 KiB
C++
//===-- MainLoopBase.h ------------------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLDB_HOST_MAINLOOPBASE_H
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#define LLDB_HOST_MAINLOOPBASE_H
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#include "lldb/Utility/IOObject.h"
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#include "lldb/Utility/Status.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/Support/ErrorHandling.h"
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#include <functional>
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#include <mutex>
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namespace lldb_private {
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// The purpose of this class is to enable multiplexed processing of data from
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// different sources without resorting to multi-threading. Clients can register
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// IOObjects, which will be monitored for readability, and when they become
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// ready, the specified callback will be invoked. Monitoring for writability is
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// not supported, but can be easily added if needed.
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//
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// The RegisterReadObject function return a handle, which controls the duration
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// of the monitoring. When this handle is destroyed, the callback is
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// deregistered.
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//
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// Since this class is primarily intended to be used for single-threaded
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// processing, it does not attempt to perform any internal synchronisation and
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// any concurrent accesses must be protected externally. However, it is
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// perfectly legitimate to have more than one instance of this class running on
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// separate threads, or even a single thread.
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class MainLoopBase {
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private:
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class ReadHandle;
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public:
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MainLoopBase() : m_terminate_request(false) {}
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virtual ~MainLoopBase() = default;
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typedef std::unique_ptr<ReadHandle> ReadHandleUP;
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typedef std::function<void(MainLoopBase &)> Callback;
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virtual ReadHandleUP RegisterReadObject(const lldb::IOObjectSP &object_sp,
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const Callback &callback,
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Status &error) = 0;
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// Add a pending callback that will be executed once after all the pending
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// events are processed. The callback will be executed even if termination
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// was requested.
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void AddPendingCallback(const Callback &callback);
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// Waits for registered events and invoke the proper callbacks. Returns when
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// all callbacks deregister themselves or when someone requests termination.
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virtual Status Run() { llvm_unreachable("Not implemented"); }
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// This should only be performed from a callback. Do not attempt to terminate
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// the processing from another thread.
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virtual void RequestTermination() { m_terminate_request = true; }
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protected:
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ReadHandleUP CreateReadHandle(const lldb::IOObjectSP &object_sp) {
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return ReadHandleUP(new ReadHandle(*this, object_sp->GetWaitableHandle()));
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}
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virtual void UnregisterReadObject(IOObject::WaitableHandle handle) = 0;
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// Interrupt the loop that is currently waiting for events and execute
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// the current pending callbacks immediately.
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virtual void TriggerPendingCallbacks() = 0;
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void ProcessPendingCallbacks();
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std::mutex m_callback_mutex;
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std::vector<Callback> m_pending_callbacks;
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bool m_terminate_request : 1;
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private:
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class ReadHandle {
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public:
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~ReadHandle() { m_mainloop.UnregisterReadObject(m_handle); }
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private:
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ReadHandle(MainLoopBase &mainloop, IOObject::WaitableHandle handle)
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: m_mainloop(mainloop), m_handle(handle) {}
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MainLoopBase &m_mainloop;
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IOObject::WaitableHandle m_handle;
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friend class MainLoopBase;
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ReadHandle(const ReadHandle &) = delete;
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const ReadHandle &operator=(const ReadHandle &) = delete;
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};
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MainLoopBase(const MainLoopBase &) = delete;
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const MainLoopBase &operator=(const MainLoopBase &) = delete;
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};
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} // namespace lldb_private
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#endif // LLDB_HOST_MAINLOOPBASE_H
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