src/script/cpp_api/s_async.cpp

   1 /*
   2 Minetest
   3 Copyright (C) 2013 sapier, <sapier AT gmx DOT net>
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU Lesser General Public License as published by
   7 the Free Software Foundation; either version 2.1 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU Lesser General Public License for more details.
  14
  15 You should have received a copy of the GNU Lesser General Public License along
  16 with this program; if not, write to the Free Software Foundation, Inc.,
  17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18 */
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22
  23 extern "C" {
  24 #include "lua.h"
  25 #include "lauxlib.h"
  26 #include "lualib.h"
  27 }
  28
  29 #include "server.h"
  30 #include "s_async.h"
  31 #include "log.h"
  32 #include "filesys.h"
  33 #include "porting.h"
  34 #include "common/c_internal.h"
  35
  36 /******************************************************************************/
  37 AsyncEngine::AsyncEngine() :
  38         initDone(false),
  39         jobIdCounter(0)
  40 {
  41 }
  42
  43 /******************************************************************************/
  44 AsyncEngine::~AsyncEngine()
  45 {
  46
  47         // Request all threads to stop
  48         for (std::vector<AsyncWorkerThread *>::iterator it = workerThreads.begin();
  49                         it != workerThreads.end(); it++) {
  50                 (*it)->stop();
  51         }
  52
  53
  54         // Wake up all threads
  55         for (std::vector<AsyncWorkerThread *>::iterator it = workerThreads.begin();
  56                         it != workerThreads.end(); it++) {
  57                 jobQueueCounter.post();
  58         }
  59
  60         // Wait for threads to finish
  61         for (std::vector<AsyncWorkerThread *>::iterator it = workerThreads.begin();
  62                         it != workerThreads.end(); it++) {
  63                 (*it)->wait();
  64         }
  65
  66         // Force kill all threads
  67         for (std::vector<AsyncWorkerThread *>::iterator it = workerThreads.begin();
  68                         it != workerThreads.end(); it++) {
  69                 delete *it;
  70         }
  71
  72         jobQueueMutex.lock();
  73         jobQueue.clear();
  74         jobQueueMutex.unlock();
  75         workerThreads.clear();
  76 }
  77
  78 /******************************************************************************/
  79 bool AsyncEngine::registerFunction(const char* name, lua_CFunction func)
  80 {
  81         if (initDone) {
  82                 return false;
  83         }
  84         functionList[name] = func;
  85         return true;
  86 }
  87
  88 /******************************************************************************/
  89 void AsyncEngine::initialize(unsigned int numEngines)
  90 {
  91         initDone = true;
  92
  93         for (unsigned int i = 0; i < numEngines; i++) {
  94                 AsyncWorkerThread *toAdd = new AsyncWorkerThread(this,
  95                         std::string("AsyncWorker-") + itos(i));
  96                 workerThreads.push_back(toAdd);
  97                 toAdd->start();
  98         }
  99 }
 100
 101 /******************************************************************************/
 102 unsigned int AsyncEngine::queueAsyncJob(std::string func, std::string params)
 103 {
 104         jobQueueMutex.lock();
 105         LuaJobInfo toAdd;
 106         toAdd.id = jobIdCounter++;
 107         toAdd.serializedFunction = func;
 108         toAdd.serializedParams = params;
 109
 110         jobQueue.push_back(toAdd);
 111
 112         jobQueueCounter.post();
 113
 114         jobQueueMutex.unlock();
 115
 116         return toAdd.id;
 117 }
 118
 119 /******************************************************************************/
 120 LuaJobInfo AsyncEngine::getJob()
 121 {
 122         jobQueueCounter.wait();
 123         jobQueueMutex.lock();
 124
 125         LuaJobInfo retval;
 126         retval.valid = false;
 127
 128         if (!jobQueue.empty()) {
 129                 retval = jobQueue.front();
 130                 jobQueue.pop_front();
 131                 retval.valid = true;
 132         }
 133         jobQueueMutex.unlock();
 134
 135         return retval;
 136 }
 137
 138 /******************************************************************************/
 139 void AsyncEngine::putJobResult(LuaJobInfo result)
 140 {
 141         resultQueueMutex.lock();
 142         resultQueue.push_back(result);
 143         resultQueueMutex.unlock();
 144 }
 145
 146 /******************************************************************************/
 147 void AsyncEngine::step(lua_State *L)
 148 {
 149         int error_handler = PUSH_ERROR_HANDLER(L);
 150         lua_getglobal(L, "core");
 151         resultQueueMutex.lock();
 152         while (!resultQueue.empty()) {
 153                 LuaJobInfo jobDone = resultQueue.front();
 154                 resultQueue.pop_front();
 155
 156                 lua_getfield(L, -1, "async_event_handler");
 157
 158                 if (lua_isnil(L, -1)) {
 159                         FATAL_ERROR("Async event handler does not exist!");
 160                 }
 161
 162                 luaL_checktype(L, -1, LUA_TFUNCTION);
 163
 164                 lua_pushinteger(L, jobDone.id);
 165                 lua_pushlstring(L, jobDone.serializedResult.data(),
 166                                 jobDone.serializedResult.size());
 167
 168                 PCALL_RESL(L, lua_pcall(L, 2, 0, error_handler));
 169         }
 170         resultQueueMutex.unlock();
 171         lua_pop(L, 2); // Pop core and error handler
 172 }
 173
 174 /******************************************************************************/
 175 void AsyncEngine::pushFinishedJobs(lua_State* L) {
 176         // Result Table
 177         MutexAutoLock l(resultQueueMutex);
 178
 179         unsigned int index = 1;
 180         lua_createtable(L, resultQueue.size(), 0);
 181         int top = lua_gettop(L);
 182
 183         while (!resultQueue.empty()) {
 184                 LuaJobInfo jobDone = resultQueue.front();
 185                 resultQueue.pop_front();
 186
 187                 lua_createtable(L, 0, 2);  // Pre-allocate space for two map fields
 188                 int top_lvl2 = lua_gettop(L);
 189
 190                 lua_pushstring(L, "jobid");
 191                 lua_pushnumber(L, jobDone.id);
 192                 lua_settable(L, top_lvl2);
 193
 194                 lua_pushstring(L, "retval");
 195                 lua_pushlstring(L, jobDone.serializedResult.data(),
 196                         jobDone.serializedResult.size());
 197                 lua_settable(L, top_lvl2);
 198
 199                 lua_rawseti(L, top, index++);
 200         }
 201 }
 202
 203 /******************************************************************************/
 204 void AsyncEngine::prepareEnvironment(lua_State* L, int top)
 205 {
 206         for (std::map<std::string, lua_CFunction>::iterator it = functionList.begin();
 207                         it != functionList.end(); it++) {
 208                 lua_pushstring(L, it->first.c_str());
 209                 lua_pushcfunction(L, it->second);
 210                 lua_settable(L, top);
 211         }
 212 }
 213
 214 /******************************************************************************/
 215 AsyncWorkerThread::AsyncWorkerThread(AsyncEngine* jobDispatcher,
 216                 const std::string &name) :
 217         Thread(name),
 218         ScriptApiBase(),
 219         jobDispatcher(jobDispatcher)
 220 {
 221         lua_State *L = getStack();
 222
 223         // Prepare job lua environment
 224         lua_getglobal(L, "core");
 225         int top = lua_gettop(L);
 226
 227         // Push builtin initialization type
 228         lua_pushstring(L, "async");
 229         lua_setglobal(L, "INIT");
 230
 231         jobDispatcher->prepareEnvironment(L, top);
 232 }
 233
 234 /******************************************************************************/
 235 AsyncWorkerThread::~AsyncWorkerThread()
 236 {
 237         sanity_check(!isRunning());
 238 }
 239
 240 /******************************************************************************/
 241 void* AsyncWorkerThread::run()
 242 {
 243         lua_State *L = getStack();
 244
 245         std::string script = getServer()->getBuiltinLuaPath() + DIR_DELIM + "init.lua";
 246         try {
 247                 loadScript(script);
 248         } catch (const ModError &e) {
 249                 errorstream << "Execution of async base environment failed: "
 250                         << e.what() << std::endl;
 251                 FATAL_ERROR("Execution of async base environment failed");
 252         }
 253
 254         int error_handler = PUSH_ERROR_HANDLER(L);
 255
 256         lua_getglobal(L, "core");
 257         if (lua_isnil(L, -1)) {
 258                 FATAL_ERROR("Unable to find core within async environment!");
 259         }
 260
 261         // Main loop
 262         while (!stopRequested()) {
 263                 // Wait for job
 264                 LuaJobInfo toProcess = jobDispatcher->getJob();
 265
 266                 if (toProcess.valid == false || stopRequested()) {
 267                         continue;
 268                 }
 269
 270                 lua_getfield(L, -1, "job_processor");
 271                 if (lua_isnil(L, -1)) {
 272                         FATAL_ERROR("Unable to get async job processor!");
 273                 }
 274
 275                 luaL_checktype(L, -1, LUA_TFUNCTION);
 276
 277                 // Call it
 278                 lua_pushlstring(L,
 279                                 toProcess.serializedFunction.data(),
 280                                 toProcess.serializedFunction.size());
 281                 lua_pushlstring(L,
 282                                 toProcess.serializedParams.data(),
 283                                 toProcess.serializedParams.size());
 284
 285                 int result = lua_pcall(L, 2, 1, error_handler);
 286                 if (result) {
 287                         PCALL_RES(result);
 288                         toProcess.serializedResult = "";
 289                 } else {
 290                         // Fetch result
 291                         size_t length;
 292                         const char *retval = lua_tolstring(L, -1, &length);
 293                         toProcess.serializedResult = std::string(retval, length);
 294                 }
 295
 296                 lua_pop(L, 1);  // Pop retval
 297
 298                 // Put job result
 299                 jobDispatcher->putJobResult(toProcess);
 300         }
 301
 302         lua_pop(L, 2);  // Pop core and error handler
 303
 304         return 0;
 305 }
 306