1 files changed, 138 insertions, 0 deletions
diff --git a/Source/Compat/processpool.h b/Source/Compat/processpool.h
new file mode 100644
index 00000000..1d040a2a
--- /dev/null
+++ b/Source/Compat/processpool.h
@@ -0,0 +1,138 @@
+//-----------------------------------------------------------------------------
+//           Name: processpool.h
+//      Developer: Wolfire Games LLC
+//    Description: 
+//        License: Read below
+//-----------------------------------------------------------------------------
+//
+//   Copyright 2022 Wolfire Games LLC
+//
+//   Licensed under the Apache License, Version 2.0 (the "License");
+//   you may not use this file except in compliance with the License.
+//   You may obtain a copy of the License at
+//
+//       http://www.apache.org/licenses/LICENSE-2.0
+//
+//   Unless required by applicable law or agreed to in writing, software
+//   distributed under the License is distributed on an "AS IS" BASIS,
+//   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//   See the License for the specific language governing permissions and
+//   limitations under the License.
+//
+//-----------------------------------------------------------------------------
+#pragma once
+
+#include <Utility/disallow_copy_and_assign.h>
+
+#include <string>
+#include <vector>
+#include <queue>
+#include <map>
+
+using std::string;
+using std::map;
+using std::vector;
+using std::queue;
+
+#ifdef _WIN32
+#define NOMINMAX
+#include <windows.h>
+class OSProcess {
+    public:
+        OSProcess(const string &worker_path);
+        ~OSProcess();
+        
+        string WaitForChildMessage();
+        void SendMessageToChild(const string &msg);
+    private:
+    
+        HANDLE read_pipe_;
+        HANDLE write_pipe_;
+        PROCESS_INFORMATION process_info_;
+    
+        DISALLOW_COPY_AND_ASSIGN(OSProcess);
+};
+#else 
+#include <pthread.h>
+#include <unistd.h>
+class OSProcess {
+public:
+    OSProcess(const string &worker_path);
+    ~OSProcess();
+    
+    string WaitForChildMessage();
+    void SendMessageToChild(const string &msg);
+private:
+    int read_pipe_;
+    int write_pipe_;
+    int process_info_;
+    
+    DISALLOW_COPY_AND_ASSIGN(OSProcess);
+};
+#endif //_WIN32
+
+class ProcessPool;
+class ProcessHandle {
+public:
+    void Process(const string& task);
+    inline bool idle(){return idle_;}
+    void ProcessInBackground();
+    
+    ProcessHandle(const string &worker_path, ProcessPool* parent_process_pool);
+   
+private:
+    bool idle_;
+    OSProcess os_process_;
+    ProcessPool* parent_process_pool_;
+    
+    bool ProcessMessageFromChild(const string& msg);
+    DISALLOW_COPY_AND_ASSIGN(ProcessHandle);
+};
+
+
+class ProcessPool {
+public:
+    // Change number of process handlers
+    void Resize(int _size);
+    
+    typedef int (*JobFunctionPtr)(int argc, const char* argv[]);
+    typedef map<string, ProcessPool::JobFunctionPtr> JobMap;
+    enum Error{SUCCESS = 0,
+               NO_IDLE_PROCESS = -1,
+               NO_TASK_IN_QUEUE = -2};
+    static bool AmIAWorkerProcess( int argc, char* argv[] );
+    static int WorkerProcessMain(const JobMap &job_map);
+
+    void NotifyTaskComplete();
+    void Schedule(const string& task);
+    void WaitForTasksToComplete();
+    void ClearQueuedTasks();
+    int NumProcesses();
+    
+    ProcessPool(const string &worker_path, int size=0);
+    ~ProcessPool();
+private:
+    
+    // Attempts to start processing the first task in the queue in the first
+    // idle process. Can return SUCCESS, NO_IDLE_PROCESS or NO_TASK_IN_QUEUE. 
+    ProcessPool::Error ProcessFirstTaskInQueue();
+    
+    // Returns index of the first idle process in pool, or -1 if there
+    // are no idle processes
+    int GetIdleProcessIndex();
+    
+    string worker_path_;
+    vector<ProcessHandle*> processes_;
+    queue<string> tasks_;
+#ifdef _WIN32
+    HANDLE mutex_;
+    HANDLE idle_event_;
+#else
+    pthread_mutex_t mutex_;
+    pthread_mutex_t idle_event_mutex_;
+    pthread_cond_t idle_event_cond_;
+    bool idle_event_bool_;
+#endif
+    
+    DISALLOW_COPY_AND_ASSIGN(ProcessPool);
+};